Academic article

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• Kristian Snekvik; Rumi Nakamura; Nikolai Østgaard et al. (2008). The Hall current system revealed as a statistical significant pattern during fast flows. (external link)
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• Jone Peter Reistad; Karl Magnus Laundal; Nikolai Østgaard et al. (2021). Quantifying the Lobe Reconnection Rate During Dominant IMF By Periods and Different Dipole Tilt Orientations. (external link)
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• C.J. Farrugia; Per Even Sandholt; R. B. Torbert et al. (2004). Temporal and spatial aspects of the cusp inferred from local and global ground- and space-based observations in a case study. (external link)
• David Alexandre Stephan Sarria; Nikolai Østgaard; Pavlo Kochkin et al. (2021). Constraining Spectral Models of a Terrestrial Gamma-Ray Flash From a Terrestrial Electron Beam Observation by the Atmosphere-Space Interactions Monitor. (external link)
• Kristian Snekvik; Nikolai Østgaard; Paul Tenfjord et al. (2017). Dayside and nightside magnetic field responses at 780 km altitude to dayside reconnection. (external link)
• Camilla Sætre; Johan Stadsnes; H Nesse et al. (2004). Energetic electron precipitation and the NO abundance in the upper atmosphere: A direct comparison during a geomagnetic storm. (external link)
• Anil Bhardwaj; G. Randall Gladstone; Ronald F. Elsner et al. (2007). First terrestrial soft X-ray auroral observation by the Chandra X-ray Observatory. (external link)
• Nikolai Lehtinen; Nikolai Østgaard (2018). X-ray Emissions in a Multiscale Fluid Model of a Streamer Discharge. (external link)
• Paul Tenfjord; Nikolai Østgaard; Kristian Snekvik et al. (2015). How the IMF By induces a By component in the closed magnetosphere and how it leads to asymmetric currents and convection patternsin the two hemispheres. (external link)
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• Karl Magnus Laundal; Nikolai Østgaard; H. U. Frey et al. (2010). Seasonal and interplanetary magnetic field-dependent polar cap contraction during substorm expansion phase. (external link)
• Stein Haaland; Bjørn Lybekk; Lukas Maes et al. (2017). North-south asymmetries in cold plasma density in the magnetotail lobes: Cluster observations. (external link)
• David Sarria; Pavlo Kochkin; Nikolai Østgaard et al. (2019). The First Terrestrial Electron Beam Observed by the Atmosphere-Space Interactions Monitor. (external link)
• Francisco J. Pérez-Invernón; Francisco J. Gordillo-Vázquez; María Passas-Varo et al. (2022). Multispectral Optical Diagnostics of Lightning from Space. (external link)
• Dongshuai Li; Torsten Neubert; Lasse Skaaning Husbjerg et al. (2023). Observation of Blue Corona Discharges and Cloud Microphysics in the Top of Thunderstorm Cells in Cyclone Fani. (external link)
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• Jone Peter Reistad; Nikolai Østgaard; Paul Tenfjord et al. (2016). Dynamic effects of restoring footpoint symmetry on closed magnetic field lines. (external link)
• Anders Ohma; Nikolai Østgaard; Jone Peter Reistad et al. (2019). Observations of asymmetric lobe convection for weak and strong tail activity. (external link)
• Brant Edward Carlson; Thomas Gjesteland; Nikolai Østgaard (2011). Terrestrial gamma-ray flash electron beam geometry, fluence, and detection frequency. (external link)
• Brant Edward Carlson; Thomas Gjesteland; Nikolai Østgaard (2012). Connecting the terrestrial gamma-ray flash source strength and observed fluence distributions. (external link)
• Liisa Juusola; Nikolai Østgaard; Eija Irene Tanskanen (2011). Statistics of plasma sheet convection. (external link)
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• Ragnhild Schrøder Hansen; Nikolai Østgaard; Thomas Gjesteland et al. (2013). How simulated fluence of photons from terrestrial gamma ray flashes at aircraft and balloon altitudes depends on initial parameters. (external link)
• Dongshuai Li; Alejandro Luque; F.J. Gordillo-Vazquez et al. (2023). Different Types of Corona Discharges Associated With High-Altitude Positive Narrow Bipolar Events Nearby Cloud Top. (external link)
• Thomas Gjesteland; Nikolai Østgaard; Paul H. Connell et al. (2010). Effects of dead time losses on terrestrial gamma ray flash measurements with the Burst and Transient Source Experiment. (external link)
• M.D. Caballero-García; E. Göǧüş; J. Navarro-González et al. (2025). X-ray and gamma-ray timing of GRB 180720B, GRB 181222B, GRB 211211A, and GRB 220910A observed with Fermi and ASIM. (external link)
• Nikolai Østgaard; Thomas Gjesteland; Brant Edward Carlson et al. (2013). Simultaneous observations of optical lightning and terrestrial gamma ray flash from space. (external link)
• Nikolai Østgaard; Karl Magnus Laundal; Liisa Juusola et al. (2012). Correction to 'Interhemispherical asymmetry of substorm onset locations and the Interplanetary Magnetic Field.'. (external link)
• Yngve Skogseide; Linga Reddy Cenkeramaddi; Georgi Genov et al. (2012). BGO front-end electronics and signal processing in the MXGS instrument for the ASIM mission. (external link)
• Arne Åsnes; Johan Stadsnes; J. Bjordal et al. (2004). Pi2-pulsations observed in energetic electron precipitation and magnetic field in association with a substorm surge. (external link)
• A. Kozlovsky; V. Safargaleev; Nikolai Østgaard et al. (2005). On the motion of dayside auroras caused by a solar wind pressure pulse. (external link)
• Nikolai Østgaard; S.B. Mende; H.U. Frey et al. (2004). Interplanetary magnetic field control of the location of substorm onset and auroral features in the conjugate hemispheres. (external link)
• H.U. Frey; G. Haerendel; S.B. Mende et al. (2004). Sub-auroral morning proton spots (SAMPS) as a result of plasmapause-ring current interaction. (external link)
• Oscar A. van der Velde; Javier Navarro-González; Ferran Fabró et al. (2024). Imaging of 3 bright terrestrial gamma-ray flashes by the atmosphere-space interactions monitor and their parent thunderstorms. (external link)
• H. U. Frey; O. Amm; C. C. Chaston et al. (2010). Small and meso-scale properties of a substorm onset auroral arc. (external link)
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• Dongshuai Li; Alejandro Luque; F.J. Gordillo-Vázquez et al. (2021). Blue Flashes as Counterparts to Narrow Bipolar Events: The Optical Signal of Shallow In-Cloud Discharges. (external link)
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• T. Stubbs; Richard R. Vondrak; Nikolai Østgaard et al. (2005). Simultaneous observations of the auroral oval in both hemispheres under varying conditions. (external link)
• Thomas Gjesteland; Nikolai Østgaard; Andrew B. Collier et al. (2012). A new method reveals more TGFs in the RHESSI data. (external link)
• H.U. Frey; Nikolai Østgaard; T.J. Immel et al. (2004). Seasonal dependence of localized, High Latitude Dayside Aurora (HiLDA). (external link)
• C.J. Farrugia; P.E. Sandholt; R.B. Torbert et al. (2004). Temporal and spatial aspects of the cusp inferred from local and global ground- and space-based observations in a case study. (external link)
• Jone Peter Reistad; Karl Magnus Laundal; Nikolai Østgaard et al. (2019). Separation and quantification of ionospheric convection sources: 1. A new technique. (external link)
• Jesús A. López; Joan Montanyà; Oscar van der Velde et al. (2022). Initiation of lightning flashes simultaneously observed from space and the ground: Narrow bipolar events. (external link)
• Matthias Heumesser; Olivier Chanrion; Torsten Neubert et al. (2021). Spectral Observations of Optical Emissions Associated With Terrestrial Gamma-Ray Flashes. (external link)
• Chris Alexander Skeie; Nikolai Østgaard; Nikolai Lehtinen et al. (2020). Constraints on Recoil Leader Properties Estimated from X-ray Emissions in Aircraft-Triggered Discharges. (external link)
• Kjetil Albrechtsen; Nikolai Østgaard; Nini Berge et al. (2018). Observationally Weak TGFs in the RHESSI Data. (external link)
• Karl Magnus Laundal; Jesper Gjerløv; Nikolai Østgaard et al. (2016). The impact of sunlight on high-latitude equivalent currents. (external link)
• Andrey Mezentsev; Nikolai Lehtinen; Nikolai Østgaard et al. (2018). Spectral Characteristics of VLF Sferics Associated With RHESSI TGFs. (external link)
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• Anders Lindanger; Chris Alexander Kallevik Skeie; Martino Marisaldi et al. (2022). Production of Terrestrial Gamma-Ray Flashes During the Early Stages of Lightning Flashes. (external link)
• Thomas Gjesteland; Nikolai Østgaard; A. B. Collier et al. (2011). Confining the angular distribution of terrestrial gamma ray flash emission. (external link)
• Andrew B. Collier; Thomas Gjesteland; Nikolai Østgaard (2011). Assessing the power law distribution of TGFs. (external link)
• Karl Magnus Laundal; Nikolai Østgaard; Kristian Snekvik et al. (2010). Interhemispheric observations of emerging polar cap asymmetries. (external link)
• M.D. Caballero-García; Rahul Gupta; S.B. Pandey et al. (2023). Multiwavelength study of the luminous GRB 210619B observed with Fermi and ASIM. (external link)
• Camilla Sætre; Charles A. Barth; Johan Stadsnes et al. (2007). Thermospheric nitric oxide at higher latitudes: Model calculations with auroral energy input. (external link)
• David Alexandre Stephan Sarria; Nikolai Østgaard; Martino Marisaldi et al. (2023). Library of Simulated Gamma-Ray Glows and Application to Previous Airborne Observations. (external link)
• Pavlo Kochkin; David Alexandre Stephan Sarria; Nikolai Grigorievich Lehtinen et al. (2021). A Rapid Gamma-Ray Glow Flux Reduction Observed From 20 km Altitude. (external link)
• Casper Rutjes; David Sarria; Alexander Broberg Skeltved et al. (2016). Evaluation of monte carlo tools for high energy atmospheric physics. (external link)
• Stephen Eric Milan; Jennifer Alyson Carter; Harneet Sangha et al. (2018). Timescales of dayside and nightside field-aligned current response to changes in solar wind-magnetosphere coupling. (external link)
• Thomas Gjesteland; Nikolai Østgaard; Sante Laviola et al. (2015). Observation of intrinsically bright terrestrial gamma ray flashes from the Mediterranean basin. (external link)
• Arve Aksnes; Johan Stadsnes; Nikolai Østgaard et al. (2006). Height profiles of the ionospheric electron density derived using space-based remote sensing of UV and X ray emissions and EISCAT radar data: A ground-truth experiment. (external link)
• Jon Bjordal; L.P. Borovkov; I.A. Kornilov et al. (2000). Structure of polar aurora over Kola Peninsula and of X-Ray oval measured by PIXIE/POLAR on February 9, 1997. (external link)
• Nikolai Østgaard; Johan Stadsnes; Jon Bjordal et al. (2000). Cause of the localized maximum of X-ray emission in the morning sector: A comparison with electron measurements. (external link)
• Nikolai Østgaard; Johan Stadsnes; Jon Bjordal et al. (2000). Global X-ray emission during an isolated substorm - a case study. (external link)
• S.A. Cummer; RR Vondrak; Nikolai Østgaard et al. (2000). Global Multispectral Auroral Imaging of an Isolated Substorm. (external link)
• Anders Ohma; Nikolai Østgaard; Jone Peter Reistad et al. (2018). Evolution of Asymmetrically Displaced Footpoints During Substorms. (external link)
• S. Soler; F.J. Gordillo-Vázquez; F. J. Pérez-Invernón et al. (2021). Global Frequency and Geographical Distribution of Nighttime Streamer Corona Discharges (BLUEs) in Thunderclouds. (external link)
• Nikolai Østgaard; Kjetil Albrechtsen; Thomas Gjesteland et al. (2015). A new population of terrestrial gamma-ray flashes in the RHESSI data. (external link)
• M Berthomier; Andrew N. Fazakerley; C Forsyth et al. (2012). Alfven: magnetosphere-ionosphere connection explorers. (external link)
• Nikolai Østgaard; Brant Edward Carlson; Ragnhild Schrøder Nisi et al. (2016). Relativistic electrons from sparks in the laboratory. (external link)
• Anders Lindanger; Martino Marisaldi; David Alexandre Stephan Sarria et al. (2021). Spectral Analysis of Individual Terrestrial Gamma-ray Flashes Detected by ASIM. (external link)
• Karl Magnus Laundal; Nikolai Østgaard (2008). Persistent global proton aurora caused by high solar wind dynamic pressure. (external link)
• Sergio Soler; Francisco J. Gordillo-Vázquez; Francisco J. Pérez-Invernón et al. (2024). Parameterizations for global thundercloud corona discharge distributions. (external link)
• Nikolai Østgaard; Jone Peter Reistad; Paul Arne Riksheim Tenfjord et al. (2016). Mechanisms that Produce Auroral Asymmetries in Conjugate Hemispheres. (external link)
• Nikolai Østgaard; Glynn A. Germany; Johan Stadsnes et al. (2002). Energy analysis of substorms based on remote sensing techniques, solar wind measurements and geomagnetic indices. (external link)
• Martino Marisaldi; Marcello Galli; C. Labanti et al. (2019). On the high-energy spectral component and fine time structure of terrestrial gamma ray flashes. (external link)
• Paul Tenfjord; Nikolai Østgaard (2013). Energy transfer and flow in the solar wind-magnetosphere-ionosphere system: A new coupling function. (external link)
• Andrey Mezentsev; Nikolai Østgaard; Martino Marisaldi et al. (2024). Discerning TGF and Leader Current Pulse in ASIM Observation. (external link)
• Feifan Liu; Torsten Neubert; Olivier Chanrion et al. (2025). Ionospheric Elves Powered by Corona Discharges in Overshooting Thunderclouds. (external link)
• Chris Alexander Kallevik Skeie; Nikolai Østgaard; Andrey Mezentsev et al. (2022). The Temporal Relationship Between Terrestrial Gamma-Ray Flashes and Associated Optical Pulses From Lightning. (external link)
• Nikolai Østgaard; S.A. Cummer; Andrey Mezentsev et al. (2021). Simultaneous Observations of EIP, TGF, Elve, and Optical Lightning. (external link)
• Paul Arne Riksheim Tenfjord; Nikolai Østgaard; Robert J. Strangeway et al. (2016). Magnetospheric response and reconfiguration times following IMF By reversals. (external link)
• Kristian Snekvik; Liisa Juusola; Nikolai Østgaard et al. (2009). Reconnection Hall current system observed in the magnetotail and in the ionosphere. (external link)
• Lasse Skaaning Husbjerg; Torsten Neubert; Olivier Chanrion et al. (2022). Observations of Blue Corona Discharges in Thunderclouds. (external link)
• Pavlo Kochkin; A.P.J. van Deursen; Martino Marisaldi et al. (2017). In-Flight Observation of Gamma Ray Glows by ILDAS. (external link)
• Jone Peter Reistad; Nikolai Østgaard; Karl Magnus Laundal et al. (2013). On the non-conjugacy of nightside aurora and their generator mechanisms. (external link)
• Olaf Amm; Arve Aksnes; Johan Stadsnes et al. (2005). Mesoscale ionospheric electrodynamics of omega bands determined from ground-based electromagnetic and satellite optical observation. (external link)
• Arve Aksnes; Johan Stadsnes; Gang Lu et al. (2004). Effects of energetic electrons on the electrodynamics in the ionosphere. (external link)
• Arve Aksnes; Olaf Amm; Johan Stadsnes et al. (2005). Ionospheric conductances derived from satellite measurements of auroral UV and X-ray emissions, and ground-based electromagnetic data: A comparison. (external link)
• Carolina Maiorana; M. Marisaldi; Martin Füllekrug et al. (2021). Observation of Terrestrial Gamma-Ray Flashes at Mid Latitude. (external link)
• Jone Peter Reistad; Nikolai Østgaard; Karl Magnus Laundal et al. (2018). Observations of asymmetries in ionospheric return flow during different levels of geomagnetic activity. (external link)
• Alexander Broberg Skeltved; Nikolai Østgaard; Andrey Mezentsev et al. (2017). Constraints to do realisticmodeling of the electric field ahead of the tip of a lightning leader. (external link)
• Nikolai Østgaard; Hugh J. Christian; J. Eric Grove et al. (2019). Gamma Ray Glow Observations at 20-km Altitude. (external link)
• Anjing Huang; Steven A. Cummer; Yunjiao Pu et al. (2022). Transition in Optical and Radio Features During the Early Development of Negative Intracloud Leader. (external link)
• Nikolai Østgaard; Stephen B. Mende; Harald U. Frey et al. (2007). Auroral conjugacy studies based on global imaging. (external link)
• Anne Borg; N Ostgaard; Nikolai Østgaard et al. (2007). Simultaneous observations of magnetotail reconnection and bright X-ray aurora on 2 October 2002. (external link)
• Brant Edward Carlson; Nikolai Østgaard; Pavlo Kochkin et al. (2015). Meter-scale spark X-ray spectrum statistics. (external link)
• Stein Haaland; Anders Eriksson; Erik Engwall et al. (2012). Estimating the capture and loss of cold plasma from ionospheric outflow. (external link)
• N Ostgaard; Nikolai Østgaard; Kristian Snekvik et al. (2009). Can magnetotail reconnection produce the auroral intensities observed in the conjugate ionosphere?. (external link)

Conference lecture

• Øystein Håvard Færder; Nikolai Grigorievich Lehtinen; David Alexandre Stephan Sarria et al. (2025). A parameter-space exploration of the Relativistic Discharge Model mapping for which conditions ALOFT’s Flickering Gamma-ray Flashes are produced. (external link)
• Arve Aksnes; Johan Stadsnes; Jon Bjordal et al. (2000). Global Conductivity Maps Derived From Polar PIXIE Observations. (external link)
• Stein Håland; Nikolai Østgaard; Johan Stadsnes et al. (2000). Comparison of energy spectra in the ionosphere and in the central plasma sheet during a magnetospheric substorm. (external link)
• Stein Håland; Nikolai Østgaard; Jon Bjordal et al. (2000). Energetic Particle Signatures of Reconnection and Plasmoid Formation in the Magnetotail. (external link)
• Thomas Gjesteland; Nikolai Østgaard; Andrew B. Collier et al. (2011). Confining the angular distribution of TGF emission. (external link)
• Jone Peter Reistad; Nikolai Østgaard; Karl Magnus Laundal et al. (2014). Hemispheric differences in solar wind – magnetosphere interactions. (external link)
• Thomas Gjesteland; Nikolai Østgaard; Andrew B. Collier (2011). Constrains on the Terrestrial Gamma-ray Flashes Emission Cone by Spectral Analysis of Geolocated Events. EGU. (external link)
• Jone Peter Reistad; Nikolai Østgaard; Karl Magnus Laundal et al. (2014). Comparison of solar wind driving of the aurora in the two hemispheres due to the solar wind dynamo. (external link)
• Thomas Gjesteland; Nikolai Østgaard; Andrew B. Collier et al. (2011). Are there more TGFs in the RHESSI data. (external link)
• Brant Edward Carlson; Thomas Gjesteland; Nikolai Østgaard (2011). The frequency of terrestrial gamma-ray flash electron beam observations. (external link)
• Nikolai Østgaard; S.B. Mende; H.U. Frey et al. (2005). Global imaging of Auroral Phenomena in the Conjugate Hemispheres. (external link)
• Arve Aksnes; Johan Stadsnes; Nikolai Østgaard et al. (2005). Ionospheric global conductance maps from remote sensing of UV and X-ray emissions. (external link)
• A. Bhardwaj; R.F. Elsner; G.r. Gladstone et al. (2005). A Comparative View of X-rays from the Solar System. (external link)
• Nikolai Østgaard; Johan Stadsnes (2005). Production altitude effects on the X-ray spectrum from TGFs. (external link)
• Arve Aksnes; Johan Stadsnes; Asgeir Brekke et al. (2005). Height profiles of the ionospheric electron density derived from remote sensing of UV- and X-ray emissions and measured by EISCAT radar. (external link)
• Nikolai Østgaard; Johan Stadsnes; J. Moen et al. (2005). A double spacecraft imaging mission to study reconnection and ion outflow. (external link)
• Nikolai Østgaard; S.B. Mende; H.U. Frey et al. (2006). ICESTAR: Auroral conjugacy studies. (external link)
• Nikolai Østgaard; S.B. Mende; H.U. Frey et al. (2006). Auroral conjugacy studies based on global imaging. (external link)
• Nikolai Østgaard; S.B. Mende; H.U. Frey et al. (2006). Hemispherical asymmetries derived from conjugate auroral imaging. (external link)
• T Neubert; C Budzt-Jørgensen; I Kuvvetli et al. (2006). The Atmosphere-Space Interactions Monitor (ASIM) for the International Space Station. (external link)
• Nikolai Østgaard; S.B. Mende; H.U. Frey et al. (2006). Auroral conjugacy studies. (external link)
• Nikolai Østgaard; S.B. Mende; H.U. Frey et al. (2006). Simulaneous imaging of the reconnection spot in the opposite hemispheres during northward IMF. (external link)
• Nikolai Østgaard; S.B. Mende; H.U. Frey et al. (2006). Substorm onset asymmetries derived from conjugate auroral imaging. (external link)
• Nikolai Østgaard (2006). Remote sensing of X rays to study characteristics of electron precipitation. (external link)
• Nikolai Østgaard; S.B. Mende; H.U. Frey et al. (2006). Conjugate imaging of substorms. (external link)
• Jone Peter Reistad; Nikolai Østgaard; Karl Magnus Laundal et al. (2013). Intensity asymmetries between the northern and southern auroral ovals associated with the x-component of the Interplanetary Magnetic Field. (external link)
• Jone Peter Reistad; Stein Haaland; Nikolai Østgaard et al. (2013). Investigation of the role of IMF Bx on magnetopause characteristic past the terminator. (external link)
• Kjartan Olafsson; Nikolai Østgaard; Eija Irene Tanskanen (2007). The Spce Suitcase - instruments for exploring the near-Earth space from the classroom. (external link)
• Nikolai Østgaard (2007). IPY-ICESTAR. (external link)
• Hilde Nesse; Johan Stadsnes; Larry Paxton et al. (2005). Effects on the O/N2-ratio caused by ionospheric heating during geomagnetic storms. (external link)
• A. L Borg; Nikolai Østgaard; A. Pedersen (2005). Studies of an X-line passage 2 October 2002 using multipoint Cluster and Polar imaging data,. (external link)
• Nikolai Østgaard; A.L. Borg; Arne Åsnes et al. (2007). What are the ionospheric signatures of magnetotail reconnection?. (external link)
• A. Bhardwaj; Nikolai Østgaard (2007). olar System X-rays: Relationship with Solar X-rays and Solar Wind. (external link)
• Nikolai Østgaard; S.B. Mende; H.U. Frey et al. (2005). Auroral signatures of lobe reconnection observed simultaneously in the conjugate hemispheres. (external link)
• Nikolai Østgaard (2007). Conjugate studies. (external link)
• Thomas Gjesteland; Nikolai Østgaard; Johan Stadsnes et al. (2007). Monte Carlo simulation of the temporal behavior of Terrestrial Gamma ray Flashes. (external link)
• Nikolai Østgaard (2005). Conjugate auroral observations, Now and in the future. (external link)
• Nikolai Østgaard; Johan Stadsnes (2005). Production altitude effects on the X-ray spectrum from TGFs. (external link)
• A. Pedersen; A. Balogh; A.L. Borg et al. (2004). Electric and magnetic field and particle observations on Cluster combined with ground-based observations during substorms. (external link)
• A. Kozlovsky; A. Koustov; V. Safargaleev et al. (2004). Response of magnetospheric electric fields and dayside auroras to a solar wind pressure pulse. (external link)
• Nikolai Østgaard; S.B. Mende; H.U. Frey et al. (2004). IMF control of auroral phenomena in the conjugate hemispheres. (external link)
• Nikolai Østgaard; S.B. Mende; H.U. Frey et al. (2004). IMF control of the aurora in the conjugate hemispheres. (external link)
• Nikolai Østgaard; Johan Stadsnes (2006). X-ray spectra measured by MXGS can reveal the production altitude of TGFs. (external link)
• Nikolai Østgaard; Johan Stadsnes; T Gjesteland et al. (2006). TGF production altitude - revisiting the BATSE spectra in view of upcoming missions. (external link)
• T.J. Immel; Nikolai Østgaard; D.J. Strickland et al. (2004). IMAGE-FUV observations of the October-November 2003 flare and magnetic storm effects on Earth. (external link)
• H.U. Frey; G. Haerendel; S.B. Mende et al. (2004). Sub-Auroral Morning Proton Spots (SAMPS) as a result of plasmapause-ring-current interaction. (external link)
• Nikolai Østgaard (2006). Imaging the upper atmopshere from space. (external link)
• Nikolai Østgaard; K Kauristi; A.T. Weatherwax (2006). ICESTAR A connection between IHY and IPY. (external link)
• Nikolai Østgaard; T.J. Immel (2006). Global imaging to predict space weather. (external link)
• Jone Peter Reistad; Stein Haaland; Nikolai Østgaard et al. (2013). Investigation of a possible IMF Bx influence on magnetopause characteristic. (external link)
• Nikolai Østgaard; A.L. Borg; Arne Åsnes et al. (2007). What are the ionospheric signatures of magnetotail reconnection?. (external link)
• Nikolai Østgaard (2007). Conjugate studies. (external link)
• Karl Magnus Laundal; Nikolai Østgaard (2007). Solar wind pressure as a cause for persistent proton precipitation. (external link)
• Anders Groth Helland; Nikolai Østgaard; Kjetil Ullaland et al. (2007). ASIM. (external link)
• Astrid Orr; Nikolai Østgaard (2007). ESA's Atmosphere-Space Interactions Monitor (ASIM) for the ISS. (external link)
• Johan Stadsnes; Jon Bjordal; Nikolai Østgaard et al. (2000). Temporal and Spatial Features of the Energetic Electron Precipitation During Substorms. (external link)
• Johan Stadsnes; Jon Bjordal; Nikolai Østgaard et al. (2000). Temporal and Spatial Features of the Energetic Electron Precipitation During Substroms. (external link)
• G.r. Gladstone; R.F. Elsner; A. Bhardwaj et al. (2004). Chandra observations of soft X-ray emissions from Earth and Jupiter. (external link)
• H.U. Frey; S.B. Mende; T.J. Immel et al. (2004). The combination of auroral imaging and spacecraft in-situ measurements for M-I coupling research. (external link)
• A. Kozlovsky; A. Koustov; V. Safargaleev et al. (2004). Response of dayside auroras and ionospheric plasma flows to a solar wind pressure pulse. (external link)
• A. Bhardwaj; R.F. Elsner; G.r. Gladstone et al. (2004). First terrestrial soft X-ray aurora observations by Chandra. (external link)
• T. Stubbs; Richard R. Vondrak; Nikolai Østgaard et al. (2004). Simultaneous observations of the auroral oval in both hemispheres under various conditions. (external link)
• H.U. Frey; Nikolai Østgaard; T.J. Immel et al. (2004). Seasonal dependence of localized, High Latitude Dayside Aurora (HiLDA). (external link)
• Nikolai Østgaard; Johan Stadsnes; Jon Bjordal et al. (2000). Global energy input derived from UVI and PIXIE. (external link)
• Nikolai Østgaard; Johan Stadsnes; Jon Bjordal et al. (2000). Global energy input derived from UVI and PIXIE. (external link)
• Anders Ohma; Nikolai Østgaard; Jone Peter Reistad et al. (2019). How asymmetries in Geospace evolve during increased tail reconnection. (external link)
• Jone Peter Reistad; Karl Magnus Laundal; Nikolai Østgaard et al. (2018). Plasma circulation inside the polar cap and lobe reconnection. (external link)
• Nikolai Østgaard; Johan Stadsnes; G. Germany et al. (2000). Energy Analysis of an Isolated Substorm Based on Remote Sensing Techniques. (external link)
• Anders Ohma; Nikolai Østgaard; Jone Peter Reistad et al. (2020). How tail reconnection affects the asymmetric state of the magnetosphere in the LFM model. (external link)
• Johan Stadsnes; Jon Bjordal; Nikolai Østgaard et al. (2000). Temporal and Spatial Features of the Energetic Electron Precipitation During Substorms. (external link)
• Brant Edward Carlson; Z Scherre; K Webere et al. (2013). Spatial Correlations and Distributions in Energetic Electron Production by Meter­Scale Sparks. (external link)
• Nikolai Østgaard (2023). The ALOFT mission: a flight campaign for TGF and gamma-ray glow observations over Central America and the Caribbean in July 2023. (external link)
• J. Montanya; F Fabro; O van der Velde et al. (2014). Lightning activity and radar for a TGF case in Colombia. (external link)
• Nikolai Østgaard (2023). Results from the ALOFT mission: a flight campaign for TGF and gamma-ray glow observations over Central America and the Caribbean in July 2023. (external link)
• Nikolai Østgaard (2024). TGF and gamma-ray glow highlights from the ALOFT 2023 flight campaign. (external link)
• Nikolai Østgaard (2013). UV and X-ray imaging of aurora and other atmospheric phenomena. (external link)
• Nikolai Østgaard; Brant Edward Carlson; Øystein Grøndahl et al. (2014). Search for X-rays and relativistic electrons in laboratory discharge experiments. (external link)
• N. A. Kelley; David M. Smith; G. S. Bowers et al. (2014). Recent Results from ADELE and RHESSI. (external link)
• Nikolai Østgaard; Jone Peter Reistad; Paul Tenfjord et al. (2013). What are the mechanisms that produce auroral asymmetries in the conjugate hemispheres?. (external link)
• Nikolai Østgaard (2014). TGF observations. (external link)
• Nikolai Østgaard; Thomas Gjesteland; Brant Edward Carlson et al. (2014). First simultaneous observations of optical lightning and terrestrial gamma flash from space. (external link)
• N. A. Kelley; David M. Smith; G. S. Bowers et al. (2013). Recent Results from ADELE and RHESSI. (external link)
• Stein Haaland; Karl Magnus Laundal; Bjørn Lybekk et al. (2017). North-south asymmetries in lobe density: Cluster observations. (external link)
• Stein Haaland; Bjørn Lybekk; Lukas Maes et al. (2017). North-South asymmetries in cold plasma density. (external link)
• Stein Haaland; Lisa Baddeley; Kjartan Olafsson et al. (2017). Looking South for the Northern Lights:Substorm Physics as University Curriculum. (external link)
• David M. Smith; P Buzbee; A Infanger et al. (2013). Results from the third RHESSI catalog of Terrestrial Gamma-ray Flashes. (external link)
• Vegard Aamodt; Nikolai Østgaard; Thomas Gjesteland et al. (2015). Search for Terrestrial Electron Beams (TEBs) in SAMPEX data. (external link)
• Thomas Gjesteland; Hugh Christian; Nikolai Østgaard (2015). An observation of a TGF from the convective core of a thundercloud. (external link)
• Stein Egil Håland; Finn Søraas; P. Daly et al. (2011). Determination of polar cap size and shape using energetic particles. (external link)
• Karl Magnus Laundal; Matthias Förster; Kristian Snekvik et al. (2015). Effects of electric field component representation on estimated cross polar cap potential - Implications for interhemispheric asymmetries. (external link)
• Andrew Infanger; David M. Smith; Thomas Gjesteland et al. (2014). Toward an optimized Third Catalog of RHESSI TGFs. (external link)
• Paul Tenfjord; Kristian Snekvik; Nikolai Østgaard et al. (2015). Generation of Birkeland Currents during IMF By; Mechanisms and theory. (external link)
• Andrew Mezentsev; Nikolai Østgaard; Thomas Gjesteland et al. (2015). VLF sferics associated with TGFs. (external link)
• Kristian Snekvik; Eija Irene Tanskanen; Nikolai Østgaard (2011). Flux cloaure during magnetotail reconnection. (external link)
• Nikolai Østgaard (2011). Auroral asymmetries in the conjugate hemispheres. (external link)
• Andrew B. Collier; Thomas Gjesteland; Nikolai Østgaard (2011). Terrestrial Gamma-ray Flash Intensity Distribution. (external link)
• Nikolai Østgaard (2011). Auroral asymmetries in the conjugate hemispheres. (external link)
• J-B Renard; J. Pincon; Nikolai Østgaard et al. (2011). Imapct of recent results About TGFs and TLEs to the scientific return OF the cobrat project. (external link)
• Liisa Juusola; Nikolai Østgaard; Eija Irene Tanskanen (2011). Statistics of Plasma Sheet Convection. (external link)
• Kristian Snekvik; Karl Magnus Laundal; Nikolai Østgaard et al. (2015). Magnetic field patterns near the polar cap boundary. (external link)
• Alexander Broberg Skeltved; Nikolai Østgaard; Thomas Gjesteland et al. (2015). Modeling the production and acceleration of runaway electrons in strong inhomogeneous electric fields with GEANT4. (external link)
• Nikolai Lehtinen; Nikolai Østgaard (2015). Dimension of a fractal streamer structure. (external link)
• Nikolai Østgaard (2011). The global auroral response to solar wind - Earth magnetosphere coupling. (external link)
• Y. Khotyaintsev; A Retino; Andris Vaivads et al. (2011). Particle Acceleration During Solar Flares and Magnetospheric Substorms. (external link)
• Brant Edward Carlson; Thomas Gjesteland; Nikolai Østgaard (2011). The TGF source luminosity distribution. (external link)
• Nikolai Østgaard; Karl Magnus Laundal; Johan Stadsnes (2011). Auroral asymmetries in the conjugate hemispheres. (external link)
• Nikolai Østgaard; Ragnhild Schrøder Hansen; Thomas Gjesteland et al. (2011). Occurence frequency and fluence of TGFs. (external link)
• Brant Edward Carlson; G Fishman; M. S. Briggs et al. (2011). Modeling TGF electron beams and constraints on the TGF source. (external link)
• Nikolai Østgaard; Brant Edward Carlson; Ragnhild Schrøder Hansen et al. (2011). The true distribution of TGF fluence measured from space. (external link)
• Siri M. Vaktdal; Nikolai Østgaard; Thomas Gjesteland et al. (2011). TGF dependence on magnetic latitude and solar zenith angle. (external link)
• Karl Magnus Laundal; Matthias Förster; Stein Haaland et al. (2015). Effects of electric field component representation on estimated cross polar cap potential - Implications for interhemispheric asymmetries. (external link)
• Michael Hesse; M Kuznetsova; Yi-Hsin Liu et al. (2017). The roles of IMF By, dipole tilt, and conductance differences in establishing nonconjugate auroral features. (external link)
• H.U. Frey; C Chaston; S Fu et al. (2009). Auroral Small-and Meso-Scale Structures, Origin and Function. (external link)
• Michael Hesse; Eigil Friis-Christensen; T Moretto et al. (2017). Does the Magnetosphere go to Sleep?. (external link)
• Mike Liemohn; Pontus Brandt; Mike Denton et al. (2009). Go With the Flow: The Reductionist View of Geospace at the System Level. (external link)
• Nikolai Østgaard; Beate Krøvel Humberset; Liisa Juusola et al. (2011). Asymmetries of substorm onset location and the dynamic behavior of auroral substorms during expansion phase. (external link)
• Andrew B. Collier; Thomas Gjesteland; Nikolai Østgaard (2011). Terrestrial Gamma-Ray Flash Intensity Distribution. (external link)
• Anders Ohma; Nikolai Østgaard; Jone Peter Reistad et al. (2019). Cluster EDI Observations of the Asymmetric Plasma Convection in the Magnetotail Lobes During Different Levels of Tail Reconnection Rate. (external link)
• Olaf Amm; Arve Aksnes; Johan Stadsnes et al. (2004). Observations and analysis of ionospheric electrodynamics during a substorm recovery phase using the MIRACLE network. (external link)
• Paul Tenfjord; Nikolai Østgaard; Stein Haaland et al. (2013). Inter-hemispheric currents in the ring current region. (external link)
• Nikolai Østgaard; Ragnhild Schrøder Hansen; Thomas Gjesteland et al. (2011). Occurence frequency and fluence of TGFs. (external link)
• Nikolai Østgaard (2015). How is Earth coupled to space?. (external link)
• Nikolai Østgaard; Brant Edward Carlson; Thomas Gjesteland et al. (2015). Search for relativistic electrons in laboratory discharge experiments. (external link)
• Karl Magnus Laundal; N Olsen; C Finlay et al. (2015). Statistical maps of Birkeland currents from Swarm magnetometer measurements. (external link)
• Theresa Rexer; Nikolai Østgaard; Jone Peter Reistad et al. (2015). Current systems associated with Non-Conjugate Aurora. (external link)
• Nikolai Østgaard; Beate Krøvel Humberset; Karl Magnus Laundal et al. (2011). Auroral asymmetries in the conjugate hemispheres during substorm onset and expansion phase. (external link)
• Paul Tenfjord; Nikolai Østgaard; Stein Haaland et al. (2015). On which timescales are By induced in the closed magnetosphere?. (external link)
• Thomas Gjesteland; Nikolai Østgaard; Martino Marisaldi et al. (2013). Terrestrial Gamma ray Flashes observed over low clod tops. (external link)
• Nikolai Østgaard; Thomas Gjesteland; Brant Edward Carlson et al. (2015). Simultaneous observations of optical lightning and terrestrial gamma flash from space and radio signals on ground. (external link)
• Linga Reddy Cenkeramaddi; Georgi Genov; Anja Kohfeldt et al. (2012). Low-energy CZT detector array for the ASIM mission. (external link)
• Nikolai Østgaard (2017). Norwegian contributions to SCOSTEP/VarSITI. (external link)
• Yngve Skogseide; Linga Reddy Cenkeramaddi; Georgi Genov et al. (2012). BGO front-end electronics and signal processing in the MXGS instrument for the ASIM mission. (external link)
• Kristian Snekvik; Nikolai Østgaard; Paul Tenfjord et al. (2017). Dayside and nightside magnetic field responses at 780 km altitude to dayside reconnection.. (external link)
• Nikolai Østgaard (2017). Conjugate auroral imaging: How asymmetric can geospace be ? Magnetic storm 17 aug 2001. (external link)
• Karl Magnus Laundal; Nikolai Østgaard (2009). IMF Bx Effects on Interhemispheric Polar Cap Asymmetries Inferred From Conjugate Auroral Imaging. (external link)
• Nikolai Østgaard; Thomas Gjesteland; Paul H. Connell et al. (2009). Analysis of a subset of BATSE TGFs that do not suffer from instrumental limitations. (external link)
• Nikolai Østgaard; Thomas Gjesteland; Paul H. Connell et al. (2009). Production altitude, initial distributions and time delays for TGFs when instrumental deadtime effects are treated properly. (external link)
• Thomas Gjesteland; Nikolai Østgaard; Paul H. Connell et al. (2009). Analysis of BATSE TGFs taking instrumental limitations into account. (external link)
• Karl Magnus Laundal; Nikolai Østgaard (2009). IPY-ICESTAR Arctic Frontiers. (external link)
• Jone Peter Reistad; Nikolai Østgaard; Paul Tenfjord et al. (2015). Are there auroral signatures related to asymmetric generation of field-aligned currents in the tail due to an IMF By induced twist?. (external link)
• Johan Stadsnes; Arve Aksnes; Camilla Sætre et al. (2006). Satellite remote mapping of the precipitation of energetic electrons and their effects on the Earth's upper atmosphere. (external link)
• Arve Aksnes; Johan Stadsnes; Nikolai Østgaard et al. (2005). Height profiles of the ionospheric electron density derived from remote sensing of UV and X-ray emissions and measurements by the EISCAT radar: A comparison. (external link)
• Jone Peter Reistad; Nikolai Østgaard; Karl Magnus Laundal et al. (2017). The influence of plasma flows bringing the magnetotail back to a more symmetric configuration. (external link)
• Nikolai Østgaard; Martino Marisaldi; Kjetil Albrechtsen et al. (2017). A Synergic Approach to the Study of TGFs and Energetic Radiation from Thunderstorms. (external link)
• Johan Stadsnes; Nikolai Østgaard; Camilla Sætre et al. (2006). Global observations of the dynamics of energetic electron precipitation during substorms. (external link)
• Camilla Sætre; Johan Stadsnes; Nikolai Østgaard et al. (2005). Chemical effects of electron precipitation: Nitric Oxide in the lower thermosphere. (external link)
• Karl Magnus Laundal; Nikolai Østgaard (2008). Conjugate imaging of substorms. (external link)
• Nikolai Østgaard; Yngve Skogseide; Kjetil Ullaland et al. (2009). An X- and gamma-ray detector for observing terrestrial gamma flashes from the International Space Station. (external link)
• Paul Tenfjord; Stein Haaland; Karl Magnus Laundal et al. (2017). How the IMF By induces a By-component on closed field lines during northward IMF Bz. (external link)
• Karl Magnus Laundal; Christopher C. Finlay; NIls Olsen et al. (2017). Characterizing external influence on the large-scale polar ionospheric current system. (external link)
• Karl Magnus Laundal; Christopher C. Finlay; NIls Olsen et al. (2017). North-south asymmetries in polar ionospheric currents - effects of asymmetries in the main magnetic field. (external link)
• Karl Magnus Laundal; Nikolai Østgaard (2017). Norwegian contributions to the ISWI program. (external link)
• Karl Magnus Laundal; Nikolai Østgaard (2008). Conjugate observations of substorm onset and expansion in the two hemispheres. (external link)
• Camilla Sætre; Johan Stadsnes; Nikolai Østgaard (2005). Kjemiske effekter av elektronnedbør i den lavere termosfæren. (external link)
• Mike Liemohn; Nikolai Østgaard; Jone Peter Reistad et al. (2013). Defining and Resolving Current Systems in Geospace. (external link)
• Nikolai Østgaard (2013). Terrestrial gamma ray flashes, the most energetic photon phenomenon in our atmosphere. (external link)
• Nikolai Østgaard (2013). Nye fenomener i romforskning - gammaglimt, blå jetter og røde ånder. (external link)
• Thomas Gjesteland; Nikolai Østgaard; Martino Marisaldi et al. (2013). Unusual bright TGF from low cloud tops over the Mediterranean sea. (external link)
• Karl Magnus Laundal; Jone Peter Reistad; Paul Tenfjord et al. (2017). Seasonal and IMF-controlled variations in the large-scale true horizontal ionospheric current. (external link)
• Jone Peter Reistad; Nikolai Østgaard; Karl Magnus Laundal et al. (2014). Conjugate and non-conjugate aspects of the aurora. (external link)
• Alexander Broberg Skeltved; Nikolai Østgaard; Brant Edward Carlson et al. (2013). A study of the relativistiv runaway electron avalanche and the feedback theories to explain terrestrial gammaray production. (external link)
• Nikolai Østgaard (2013). Terrestrial Gamma-ray Flashes - the most energetic photon phenomenon in our atmosphere. (external link)
• Thomas Gjesteland; Nikolai Østgaard; Martino Marisaldi et al. (2016). Stereo Observations of Terrestrial Gamma-ray Flashes. (external link)
• T Neubert; V Reglero; Nikolai Østgaard et al. (2009). The ASIM Mission for Studies of Severe Thunderstorms,. (external link)
• Nikolai Østgaard; Karl Magnus Laundal (2009). Asymmetric aurora detected in the two hemispheres simultaneously. (external link)
• Nikolai Østgaard (2013). Terrestrial gamma ray flashes, the most energetic photon phenomenon in our atmosphere. (external link)
• Nikolai Østgaard; Karl Magnus Laundal (2009). Asymmetric aurora detected in the two hemispheres simultaneously. (external link)
• Karl Magnus Laundal; Nikolai Østgaard (2009). Conjugate aurora observations of substorms IAGA meeting. (external link)
• Nikolai Østgaard; Thomas Gjesteland; Paul H. Connell et al. (2008). Analysis of a subset of BATSE TGFs that do not suffer from instrumental limitations. (external link)
• Kjartan Olafsson; Nikolai Østgaard (2008). The Space Science Suitcase Instruments for Exploring Space Weather From the Classroom. (external link)
• Thomas Gjesteland; Nikolai Østgaard; Paul H. Connell et al. (2008). Monte Carlo simulation of the temporal behavior of Terrestrial Gamma ray Flashes. (external link)
• Nikolai Østgaard; Thomas Gjesteland; Johan Stadsnes et al. (2008). The production altitude and time delays of the terrestrial gamma flashes - revisiting the BATSE spectra. (external link)
• Jone Peter Reistad; Karl Magnus Laundal; Anders Ohma et al. (2019). A new way to identify and quantify the sources of ionospheric convection. (external link)
• Kristian Snekvik; Liisa Juusola; Olaf Amm et al. (2009). Reconnection Hall current system observed in the magnetotail and in the ionosphere. (external link)
• Nikolai Østgaard; Beate Krøvel Humberset; Karl Magnus Laundal et al. (2009). Substorm auroral asymmetries in the conjugate hemispheres during onset and expansion phase. (external link)
• Karl Magnus Laundal; Nikolai Østgaard (2009). Asymmetric aurora detected in the two hemispheres simultaneously. (external link)
• Nikolai Østgaard (2014). Birkeland Centre for Space Science. (external link)
• Alexander Broberg Skeltved; Nikolai Østgaard; Brant Edward Carlson et al. (2014). A study of the runaway relativistic electron avalanche and the feedback theory using GEANT4. (external link)
• Nikolai Østgaard; Brant Edward Carlson; Øystein Grøndahl et al. (2014). Search for X-rays and relativistic electrons in laboratory discharge experiments. (external link)
• Jone Peter Reistad; Nikolai Østgaard; Karl Magnus Laundal et al. (2014). Comparison of solar wind driving of the aurora in the two hemispheres due to solar wind dynamo. (external link)
• Nikolai Lehtinen; Umran S. Inan; Nikolai Østgaard (2014). On the spatial scale of streamers. (external link)
• Jone Peter Reistad; Stein Haaland; Nikolai Østgaard et al. (2013). Investigation of a possible IMF Bx influence on magnetopause characteristics. (external link)
• Nikolai Østgaard; Karl Magnus Laundal (2008). Auroral conjugacy studies. (external link)
• Nikolai Østgaard; Thomas Gjesteland; Johan Stadsnes et al. (2008). The production altitude and time delays of the terrestrial gamma flashes - revisiting the BATSE spectra. (external link)
• Nikolai Østgaard; Arne Åsnes; A. Pedersen et al. (2008). What are the ionospheric signatures of magnetotail reconnection?. (external link)
• Thomas Gjesteland; Nikolai Østgaard; Paul H. Connell et al. (2008). Monte Carlo simulation of the temporal behavior of Terrestrial Gamma ray Flashes and analysis of the BATSE measurements. (external link)
• Thomas Gjesteland; Nikolai Østgaard; Johan Stadsnes et al. (2008). The production altitude and time delays of the terrestrial gamma flashes - revisiting the BATSE spectra. (external link)
• Marianne Daae; Nikolai Østgaard; W Lewis (2008). Undulations on the equatorial edge of the auroral oval in the dusk sector. (external link)
• Nikolai Lehtinen; Umran S. Inan; Nikolai Østgaard (2014). On the Spatial Scale of Streamers. (external link)
• Nikolai Lehtinen; Nikolai Østgaard; Umran S. Inan (2014). Dynamics of a streamer structure. (external link)
• Ragnhild Schrøder Nisi; Nikolai Østgaard; Thomas Gjesteland (2014). An altitude and distance correction to the initial fluence distribution of TGF. (external link)
• Vegard Aamodt; Nikolai Østgaard; Thomas Gjesteland et al. (2014). Search for Terrestrial Electron Beams (TEB) in SAMPEX data. (external link)
• Thomas Gjesteland; Nikolai Østgaard; Ragnhild Schrøder Nisi et al. (2014). Twelve Years of RHESSI TGFs - The second RHESSI TGF catalog. (external link)
• Alexander Broberg Skeltved; Nikolai Østgaard; Thomas Gjesteland et al. (2014). Modelling the runaway electron avalanche and the feedback mechanism with GEANT4. (external link)
• Nikolai Østgaard (2013). Scientific Programme of Birkeland Centre in Space Physics. (external link)
• Nikolai Østgaard; Thomas Gjesteland; Hugh Christian et al. (2015). The sequence of events in a lightning stroke: terrestrial gamma ray flash, radio signal and optical lightning.. (external link)
• Anders Ohma; Nikolai Østgaard; Jone Peter Reistad et al. (2019). Observations of Asymmetric Lobe Convection for Weak and Strong Tail Reconnection. (external link)
• David Sarria; Nikolai Østgaard; Pavlo Kochkin et al. (2019). The First Terrestrial Electron Beam Observed by the Atmosphere‐Space Interactions Monitor (ASIM), EGU 2019 Presentation.. (external link)
• Nikolai Østgaard (2013). Terrestrial Gamma-ray Flashes - the most energetic photon phenomenon in our atmosphere. (external link)
• Camilla Sætre; Johan Stadsnes; Arve Aksnes et al. (2004). The impact of energetic electron precipitation on nitric oxide in the upper atmosphere - Including neutral wind effects. (external link)
• Karl Magnus Laundal; Nikolai Østgaard; Jone Peter Reistad et al. (2013). Non-Conjugate Features in the Auroral Ovals in the two Hemispheres. (external link)
• Thomas Gjesteland; Nikolai Østgaard; Andrew B. Collier et al. (2013). Terrestrial Gamma ray Flashes observed over low clod tops. (external link)
• Nikolai Østgaard; Thomas Gjesteland; Brant Edward Carlson et al. (2013). First simultaneous observations of optical lightning and terrestrial gamma flash from space. (external link)
• Andrew B. Collier; Thomas Gjesteland; Nikolai Østgaard (2013). Intensity of Lightning Associated with TGFs. (external link)
• Anders Ohma; Nikolai Østgaard; Jone Peter Reistad et al. (2019). How Asymmetries in Geospace Evolve During Substorms. (external link)
• Jone Peter Reistad; Nikolai Østgaard; Karl Magnus Laundal et al. (2013). Simultaneous global imaging as a tracer of true conjugate regions. (external link)
• Johan Stadsnes; Arve Aksnes; Camilla Sætre et al. (2008). Observations of energetic particle precipitation and effects on the mesosphere and lower thermosphere. (external link)
• Nikolai Østgaard (2024). TGF and gamma-ray glow highlights from the ALOFT 2023 flight campaign. (external link)
• Nikolai Østgaard; Thomas Gjesteland; Brant Edward Carlson et al. (2015). Simultaneous observations of optical lightning and terrestrial gamma flash and radio signals on ground. (external link)
• Hilde Nesse; Johan Stadsnes; Larry Paxton et al. (2004). Effects on the O/N2-ratio caused by energetic electron precipitation during storms. (external link)
• Jone Peter Reistad; Nikolai Østgaard; Karl Magnus Laundal et al. (2014). Asymmetric Solar Wind dynamo efficiency and IMF Bx. (external link)

Conference poster

• Øystein Håvard Færder; Nikolai Grigorievich Lehtinen; David Alexandre Stephan Sarria et al. (2025). Systematic reproduction of hard radiation from thunderclouds including ALOFT’s Flickering Gamma-ray Flashes using an ODE model resembling a Lotka-Volterra predator-prey system. (external link)
• Nikolai Østgaard (2025). The difference between multiple TGFs and FGFs. (external link)
• David Alexandre Stephan Sarria; Nikolai Østgaard; Ingrid Bjørge-Engeland et al. (2025). Evidence of gamma-ray glows observed in the relativistic feedback regime during the ALOFT 2023 flight campaign. (external link)
• Paul Tenfjord; Nikolai Østgaard; Jone Peter Reistad et al. (2014). Generation of Field Aligned Currents during IMF By: Mechanisms and theory. (external link)
• Nikolai Lehtinen; Pavlo Kochkin; Nikolai Østgaard (2016). X-ray Production in a Laboratory Streamer Discharge. (external link)
• Beate Krøvel Humberset; Nikolai Østgaard; Karl Magnus Laundal (2009). A case study of auroral conjugacy based on global imaging. (external link)
• Jone Peter Reistad; Karl Magnus Laundal; Anders Ohma et al. (2019). A new way to identify and quantify the sources of ionospheric convection. (external link)
• Ragnhild Schrøder Nisi; Nikolai Østgaard; Brant Edward Carlson et al. (2013). Modeling of the Bremsstrahlung process in connection to Terrestrial gamma-ray flashes. (external link)
• Martino Marisaldi; M Galli; A Ursi et al. (2017). On the high-energy spectral component of TGFs detected by AGILE. (external link)
• Kjartan Olafsson; Nikolai Østgaard; Eija Irene Tanskanen (2007). The Space Science Suitcase - instruments for exploring near-Earth space from the classroom. (external link)
• Paul Tenfjord; Nikolai Østgaard; Jone Peter Reistad et al. (2018). How the IMF BY induces a BY component on closed field lines during northward IMF Bz and characteristic timescales. (external link)
• Jone Peter Reistad; Nikolai Østgaard; Karl Magnus Laundal et al. (2013). Auroral intensity asymmetries associated with the x-component of the interplanetary magnetic field in the two polar hemispheres. (external link)
• Jone Peter Reistad; Karl Magnus Laundal; Nikolai Østgaard et al. (2019). Quantifying the dipole tilt influence on reverse convection cells during northward IMF using spherical elementary functions. (external link)
• Karl Magnus Laundal; Stein Haaland; Nikolai Østgaard et al. (2015). Birkeland Current Effects on High-Latitude Ground Magnetic Field Perturbations. (external link)
• Karl Magnus Laundal; Nikolai Østgaard; Jone Peter Reistad (2013). Solar wind dynamic pressure effect on global auroral intensity. (external link)
• Nikolai Østgaard; S.B. Mende; H.U. Frey et al. (2004). The Cusp Aurora in the Conjugate Hemispheres of the Earth. (external link)
• Kristian Snekvik; Nikolai Østgaard; Rumi Nakamura et al. (2008). Field aligned currents detected during fats flows in the magnetotail. (external link)
• Marianne Daae; Nikolai Østgaard; W Lewis (2008). Undulations on the Equatorial Edge of the Auroral Oval. (external link)
• Kristian Snekvik; Rumi Nakamura; Stein Haaland et al. (2008). A statistical study of the current sheet structure associated with fast flows in the magnetotail. (external link)
• Olaf Amm; Arve Aksnes; Johan Stadsnes et al. (2004). Observations and analysis of ionospheric electrodynamics during a substorm recovery phase using the MIRACLE network. (external link)
• Arve Aksnes; Johan Stadsnes; Asgeir Brekke et al. (2004). Comparing height profiles of the ionospheric electron density derived from remote sensing of UV- and X-ray emissions and from EISCAT radar data. (external link)
• Arne Åsnes; R. Friedel; M. Thomsen et al. (2004). Statistical pitch angle properties of substorm injected electron clouds and their relation to dawnside energetic electron precipitation. (external link)
• Anders Ohma; Nikolai Østgaard; Jone Peter Reistad et al. (2018). Evolution of asymmetrically displaced footpoints during substorms. (external link)
• Arve Aksnes; Olaf Amm; Johan Stadsnes et al. (2004). Ionospheric conductances derived from satellite measurements of auroral UV and X-ray emissions, and ground-based electromagnetic data: A comparison. (external link)
• Martino Marisaldi; Nikolai Østgaard; Kjetil Albrechtsen et al. (2017). A Synergic Approach to the Study of TGFs and Energetic Radiation from Thunderstorms. (external link)
• Karl Magnus Laundal; Nikolai Østgaard (2008). Auroral asymmetries in the conjugate hemispheres during strong IMF Bx. (external link)
• Paul Tenfjord; Nikolai Østgaard; Stein Haaland et al. (2015). The Impact of IMF By on the Magnetosphere-Ionosphere System. (external link)
• Camilla Sætre; Johan Stadsnes; Nikolai Østgaard et al. (2006). Chemical effects of electron precipitation - Modeled thermospheric nitric oxide. (external link)
• Camilla Sætre; Johan Stadsnes; Nikolai Østgaard et al. (2006). Electron precipitation - Energy deposition and chemical effects in the lower thermosphere. (external link)
• Andrey Mezentsev; Nikolai Lehtinen; Nikolai Østgaard et al. (2017). Spectral characteristics of VLF sferics associated with TGFs. (external link)
• Anders Ohma; Nikolai Østgaard; Jone Peter Reistad et al. (2017). Evolution of asymmetrically displaced footpoints during substorms. (external link)
• Anders Ohma; Nikolai Østgaard; Jone Peter Reistad et al. (2017). Evolution of asymmetrically displaced footpoints during substorms. (external link)
• Jone Peter Reistad; Nikolai Østgaard; Paul Tenfjord et al. (2015). On the importance of magnetotail untwisting. (external link)
• Nikolai Lehtinen; Pavlo Kochkin; Nikolai Østgaard (2017). Mechanisms of X-ray production in laboratory streamers. (external link)
• Andrey Mezentsev; Nikolai Lehtinen; Nikolai Østgaard et al. (2016). Spectral characteristics of VLF sferics associated with TGFs. (external link)
• Andrey Mezentsev; Nikolai Østgaard; Thomas Gjesteland et al. (2016). Radio emissions from RHESSI TGFs. (external link)
• Andrey Mezentsev; Nikolai Østgaard; Thomas Gjesteland et al. (2016). Radio emissions from RHESSI TGFs. (external link)
• Nikolai Østgaard; Martino Marisaldi; Pavlo Kochkin et al. (2017). How should we define terrestrial gamma-ray flashes?. (external link)
• Nikolai Lehtinen; Brant Edward Carlson; Pavlo Kochkin et al. (2017). Mechanisms important to later stages of streamer system development. (external link)
• Ninni Berge; Nikolai Østgaard; Kjetil Albrechtsen (2017). Optimization of Selection Criteria for Weak Signal TGFs. (external link)
• Nikolai Østgaard; Jone Peter Reistad; Paul Tenfjord et al. (2017). The asymmetric geospace - the most common state of the system. (external link)
• Roger Torkelsen; Nikolai Østgaard; Pavlo Kochkin (2017). Fourier analysis of high-frequency current oscillations measured in high-voltage electrical discharge experiments in the laboratory. (external link)
• Camilla Sætre; Daniel N. Baker; Charles A. Barth et al. (2004). Direct comparisons of energetic electron precipitation and nitric oxide in the upper atmosphere during geomagnetic storms. (external link)
• Alexander Broberg Skeltved; Nikolai Østgaard; Andrey Mezentsev et al. (2017). Constraints to do realistic modeling of the electric field at the tip of a lightning leader. (external link)
• Nikolai Østgaard; Hugh J. Christian; Eric Grove et al. (2017). Gamma-ray observations at 20 km altitude above thunderstorms. (external link)
• Paul Tenfjord; Stein Haaland; Karl Magnus Laundal et al. (2017). How the IMF By induces a By-component on closed field lines during northward IMF Bz. (external link)
• Kjetil Albrechtsen; Nikolai Østgaard; Martino Marisaldi et al. (2017). Estimating the global production rate of TGFs. (external link)
• Kjetil Albrechtsen; Nikolai Østgaard (2017). Assessment of the cutoff of a broken power law fitted to RHESSI data. (external link)
• Jone Peter Reistad; Nikolai Østgaard; Karl Magnus Laundal et al. (2014). Hemispheric asymmetries in the global aurora and IMF Bx. (external link)
• David Sarria; Nikolai Østgaard; Pavlo Kochkin (2017). Modeling the 511 keV background enhancements observed by aircrafts in thunderstorms. (external link)
• Ragnhild Schrøder Hansen; Nikolai Østgaard; Thomas Gjesteland et al. (2012). Fluence of photons from Terrestrial Gamma ray flashes in aircraft and balloon altitudes - dependence of initial parameters in simulations. (external link)
• Jone Peter Reistad; Nikolai Østgaard; Karl Magnus Laundal et al. (2015). On the importance of magnetotail untwist. (external link)
• Camilla Sætre; Charles A. Barth; Johan Stadsnes et al. (2005). Comparisons of electron energy flux derived from X-ray bremsstrahlung measurements and from a photochemical model for nitric oxide. (external link)
• Jone Peter Reistad; Nikolai Østgaard; Karl Magnus Laundal et al. (2017). When and where is the process of restoring symmetry important?. (external link)
• Jone Peter Reistad; Nikolai Østgaard; Paul Arne Riksheim Tenfjord et al. (2016). Dynamic effects of restoring footpoint symmetry on closed magnetic field-lines: Asymmetric Birkeland currents. (external link)
• Jone Peter Reistad; Nikolai Østgaard; Karl Magnus Laundal et al. (2013). How IMF Bx affects the two hemispheres differently. (external link)
• Jone Peter Reistad; Nikolai Østgaard; Kjellmar Oksavik (2012). How the solar wind dynamo affects the two polar regions differently. (external link)
• David Sarria; Pavlo Kochkin; Nikolai Østgaard et al. (2019). Observation of a Terrestrial Electron Beam during the tropical cyclone Joaninha in March 2019. (external link)
• Jone Peter Reistad; Nikolai Østgaard; Kjellmar Oksavik et al. (2012). Asymmetric field-aligned currents in the conjugate hemispheres. (external link)
• Paul Tenfjord; Nikolai Østgaard; Jone Peter Reistad et al. (2013). Inter-hemispheric currents in the ring current region as seen by the Cluster spacecraft. (external link)
• Paul Tenfjord; Nikolai Østgaard (2013). Energy transfer and flow in the solar wind-magnetosphere-ionosphere system: A new coupling function. (external link)
• Pavlo Kochkin; A.P.J. van Deursen; Alte de Boer et al. (2017). In-flight observation of long duration gamma-ray glows by aircraft. (external link)
• Paul Tenfjord; Nikolai Østgaard (2013). Energy transfer and flow in the solar wind-magnetosphere-ionosphere system: A new coupling function. (external link)
• Jone Peter Reistad; Nikolai Østgaard; Karl Magnus Laundal et al. (2013). How IMF Bx affects the two polar hemispheres differently. (external link)
• Paul Arne Riksheim Tenfjord; Nikolai Østgaard; Stein Haaland et al. (2016). How the IMF By induces a By component on closed field lines during northward IMF Bz. (external link)
• Kristian Snekvik; Paul Tenfjord; Nikolai Østgaard et al. (2015). Solar wind coupling times from the dayside to the nightside as observed by AMPERE. (external link)
• Lindis Merete Bjoland; Nikolai Østgaard; Kjellmar Oksavik et al. (2012). Ionospheric Signatures Associated with the 21 February 2008 Svalbard Earthquake. (external link)
• Jone Peter Reistad; Nikolai Østgaard; Karl Magnus Laundal et al. (2012). Non-conjugate aurora and inter hemispheric currents. (external link)
• Nikolai Lehtinen; Nikolai Østgaard; Pavlo Kochkin (2015). Modeling of the laboratory streamer discharge. (external link)
• Kjetil Albrechtsen; Nikolai Østgaard; Thomas Gjesteland et al. (2015). Do all lightning produce TGFs? Approaching this question using data from RHESSI and WWLLN. (external link)

Academic literature review

• Christoph Köhn; Torsten Neubert; Martin Füllekrug et al. (2025). Recent Results on Science and Innovation Related to Electrical Processes of Thunderstorms. (external link)
• S. Sembay; A. Cheney; R. Hampson et al. (2025). The Soft X-ray Imager (SXI) on the SMILE Mission. (external link)
• Nikolai Østgaard; Jan E. Balling; Thomas Riis Bjørnsen et al. (2019). The modular X- and gamma-ray sensor (MXGS) of the ASIM Payload on the International Space Station. (external link)
• Torsten Neubert; Nikolai Østgaard; Victor Reglero et al. (2019). The ASIM mission on the international space station. (external link)

Lecture

• Pavlo Kochkin; A.P.J. van Deursen; Alte de Boer et al. (2017). In-flight measurement of high-energy lightning-related atmospheric phenomena. (external link)
• Pavlo Kochkin; David Sarria; A.P.J. van Deursen et al. (2017). Positron annihilation in thunderstorms observed by ILDAS.. (external link)
• Pavlo Kochkin; A.P.J. van Deursen; Alte de Boer et al. (2017). Thunderstorm high-energy radiation measured in-flight. (external link)
• Nikolai Lehtinen; Nikolai Østgaard; Pavlo Kochkin (2016). Modeling of laboratory streamer discharge features leading to x-ray emissions. (external link)
• Nikolai Lehtinen; Pavlo Kochkin; Nikolai Østgaard (2016). Modeling of laboratory streamer discharge features associated with observations of x-ray emissions. (external link)
• Karl Magnus Laundal; Nikolai Østgaard; Jone Peter Reistad et al. (2014). Seasonal differences in ionospheric current rise and decay times. (external link)
• Pavlo Kochkin; Nikolai Lehtinen; Joan Montanyà et al. (2016). Neutron bursts from long laboratory sparks. (external link)
• Pavlo Kochkin; Alexander P.J. Van Deursen; Nikolai Østgaard (2016). High energy radiation from aircraft-triggered lightning and thunderstorm.. (external link)
• Nikolai Østgaard (2013). Jakten på jordiske gammaglimt. (external link)
• Andrey Mezentsev; Nikolai Østgaard; Thomas Gjesteland et al. (2016). Radio emissions from double RHESSI TGFs. (external link)
• Nikolai Østgaard (2007). De mystiske tvillingene - Nordlys og Sørlys. (external link)
• Nikolai Østgaard (2013). Jakten på jordiske gammaglimt. (external link)
• Nikolai Østgaard (2015). How is Earth coupled to Space?. (external link)
• Nikolai Østgaard (2015). How is Earth coupled to Space?. (external link)

Media interview

• Nikolai Østgaard; Per Barth Lilje; Unni Eikeseth (2011). Belte av antimaterie omgir jorda. (external link)
• Nikolai Østgaard; Ingeborg Kristvik (2011). Bergensk jakt på superenergi. (external link)
• Nikolai Østgaard (2007). Radio intevju om IPY i P2. (external link)
• Nikolai Østgaard (2007). intervju om IPY til forskning.no. (external link)
• Nikolai Østgaard (2007). Intervju om tiltredelse som redaktør i GRL i BT. (external link)
• Nikolai Østgaard; Roy Hilmar Svendsen; Charlotte Haarvik Sanden (2011). Spektakulært lysshow over hele Nord-Europa. (external link)
• Randi Elisabeth Taxt; Nikolai Østgaard; Jarl Giske et al. (2012). Rådyre tidsskrifter kveler økonomien til universiteter og høyskoler. (external link)
• Kjetil Ullaland; Nikolai Østgaard (2019). Dropp paraplyen og stå med bena samlet. Her er ni gode råd om lyn.. (external link)
• Nikolai Østgaard (2006). Ånder, jetter og blå alver på himmelen. (external link)
• Kjetil Ullaland; Nikolai Østgaard; Rolf-Birger Pedersen et al. (2007). SIR-2, Chandrayaan. (external link)
• Nikolai Østgaard (2006). Ånder. jetter og blå alver på himmelen. (external link)

Non-fiction book chapter

• Stein Egil Haaland; Bjørn Lybekk; Lukas Maes et al. (2021). Ion Outflow and Lobe Density: Interhemispheric Asymmetries. (external link)

Doctoral thesis (PhD)

• Camilla Sætre; Johan Stadsnes; Nikolai Østgaard (2006). The effect of energetic precipitation on the nitric oxide density in the lower thermosphere. (external link)
• Anders Ohma; Nikolai Østgaard (2019). How Asymmetries in Geospace Evolve During Increased Tail Reconnection. (external link)
• Paul Tenfjord; Nikolai Østgaard (2017). Solar wind energy transfer and the asymmetric geospace. (external link)
• Alexander Broberg Skeltved; Nikolai Østgaard (2018). Evaluating production scenarios of terrestrial gamma-ray flashes. (external link)
• Karl Magnus Laundal; Nikolai Østgaard (2010). Auroral imaging as a tracer of global magnetospheric dynamics. (external link)
• Kristian Snekvik; Nikolai Østgaard (2009). Observations of field aligned currents in the plasma sheet. (external link)
• Jone Peter Reistad; Nikolai Østgaard; Kjellmar Oksavik (2016). Mechanisms responsible for asymmetric aurora between the conjugate hemispheres. (external link)

Academic book chapter

• Anil Bhardwaj; Ronald F. Elsner; G. Randall Gladstone et al. (2009). X-ray emission from planets and comets:Relationship with SOLAR X-RAYS and SOLAR WIND. (external link)
• William Longley; Patricia Reiff; Jone Peter Reistad et al. (2017). Magnetospheric Model Performance during Conjugate Aurora. (external link)

Master’s thesis

• Beate Krøvel Humberset; Nikolai Østgaard (2009). The location and relative intensity of the aurora in the conjugate hemispheres. (external link)
• Karl Magnus Laundal; Nikolai Østgaard (2007). Storm Time Observations of the Global Proton Aurora. (external link)
• Ragnhild Schrøder Hansen; Nikolai Østgaard (2010). Observations of terrestrial Gamma-ray Flashes by high-altitude aircrafts and balloons : constraints and opportunities. (external link)
• Jill Renate Flatjord; Nikolai Østgaard (2007). The characteristics of theta aurora and implications for its production mechanisms. (external link)
• Sigurd Karlsen; Nikolai Østgaard (2007). Sammenheng mellom gjennomsnitsenergien til elektronnedbør og forskjellige emisjonslinjer i nordlyset målt med allsky kamera på Andøya. (external link)
• Thomas Gjesteland; Nikolai Østgaard (2007). Terrestrial Gamma ray Flash - En Monte Carlo-simulering for å forstå deres fysiske egenskaper. (external link)

Journal corrigendum

• Nikolai Østgaard; Karl Magnus Laundal; Beate Krøvel Humberset (2013). Correction to 'Evolution of auroral asymmetries in the conjugate hemispheres during two substorms.'. (external link)
• Torsten Neubert; Olivier Chanrion; Matthias Heumesser et al. (2021). Author Correction: Observation of the onset of a blue jet into the stratosphere (Nature, (2021), 589, 7842, (371-375), 10.1038/s41586-020-03122-6). (external link)

Research report

• Nikolai Østgaard; Johan Stadsnes; Jon Bjordal (2000). PIXIE measurements compared with directly measured electrons. (external link)
• Stein Håland; Nikolai Østgaard (2000). Multi-spacecraft study of a megnetospheric substorm. (external link)

Media feature article

• Nikolai Østgaard; Arve Aksnes (2005). Været i vårt nære verdensrom. (external link)
• Nikolai Østgaard; Arve Aksnes (2005). Romværet i vårt nære verdensrom. (external link)

Popular science book chapter

• Pål Gunnar Ellingsen; Lisa Baddeley; Dag Arne Lorentzen et al. (2016). Auroral research and the total solar eclipse.. (external link)

See a complete overview of publications in NVA.