Academic article

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• Sætre, Camilla; Stadsnes, Johan; Nesse, H et al. (2004). Energetic electron precipitation and the NO abundance in the upper atmosphere: A direct comparison during a geomagnetic storm. (external link)
• Åsnes, Arne; Stadsnes, Johan; Bjordal, J. et al. (2004). Pi2-pulsations observed in energetic electron precipitation and magnetic field in association with a substorm surge. (external link)
• Østgaard, Nikolai; Mende, S.B.; Frey, H.U. et al. (2004). Interplanetary magnetic field control of the location of substorm onset and auroral features in the conjugate hemispheres. (external link)
• Frey, H.U.; Haerendel, G.; Mende, S.B. et al. (2004). Sub-auroral morning proton spots (SAMPS) as a result of plasmapause-ring current interaction. (external link)
• Frey, H.U.; Østgaard, Nikolai; Immel, T.J. et al. (2004). Seasonal dependence of localized, High Latitude Dayside Aurora (HiLDA). (external link)
• Farrugia, C.J.; Sandholt, P.E.; Torbert, R.B. 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)
• Aksnes, Arve; Stadsnes, Johan; Lu, Gang et al. (2004). Effects of energetic electrons on the electrodynamics in the ionosphere. (external link)
• Østgaard, Nikolai; Germany, Glynn A.; Stadsnes, Johan et al. (2002). Energy analysis of substorms based on remote sensing techniques, solar wind measurements and geomagnetic indices. (external link)
• Bjordal, Jon; Borovkov, L.P.; Kornilov, I.A. 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)
• Østgaard, Nikolai; Stadsnes, Johan; Bjordal, Jon et al. (2000). Cause of the localized maximum of X-ray emission in the morning sector: A comparison with electron measurements. (external link)
• Østgaard, Nikolai; Stadsnes, Johan; Bjordal, Jon et al. (2000). Global X-ray emission during an isolated substorm - a case study. (external link)
• Cummer, S.A.; Vondrak, RR; Østgaard, Nikolai et al. (2000). Global Multispectral Auroral Imaging of an Isolated Substorm. (external link)
• Østgaard, Nikolai; Stadsnes, Johan; Aarsnes, Kjell et al. (1998). Simultaneous measurements of x-rays and electrons during a pulsating aurora. (external link)

Academic literature review

• Sembay, S.; Cheney, A.; Hampson, R. et al. (2025). The Soft X-ray Imager (SXI) on the SMILE Mission. (external link)
• Østgaard, Nikolai; Balling, Jan E.; Bjørnsen, Thomas Riis et al. (2019). The modular X- and gamma-ray sensor (MXGS) of the ASIM Payload on the International Space Station. (external link)
• Neubert, Torsten; Østgaard, Nikolai; Reglero, Victor et al. (2019). The ASIM mission on the international space station. (external link)

Poster

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

Academic lecture

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

Chapter

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

Errata

• Neubert, Torsten; Chanrion, Olivier; Heumesser, Matthias 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)
• Østgaard, Nikolai; Laundal, Karl Magnus; Humberset, Beate Krøvel (2013). Correction to 'Evolution of auroral asymmetries in the conjugate hemispheres during two substorms.'. (external link)

Doctoral dissertation

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

Interview

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

Lecture

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

Academic chapter/article/Conference paper

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

Popular scientific chapter/article

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

Masters thesis

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

Feature article

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

Report

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

See a complete overview of publications in Cristin.