Atmospheric electricity

Research on Terrestrial Gamma-ray Flashes (TGFs), gamma-ray glows, and related high-energy atmospheric phenomena related to thunderclouds and lightning discharge.

The main questions we want to answer:

• how are TGFs produced?
• what is the relation between high-energy processes in the atmosphere and the lightning discharge?
• do TGFs and related high-energy phenomena have any impact on atmospheric chemistry and dynamics?

The tools we use:

• data from the Airborne Lightning Observatory for FEGS and TGFs (ALOFT) flight campaign
• data from the Atmosphere-Space Interactions Monitor (ASIM) mission onboard the International Space Station (ISS)
• data from the Astrorivelatore Gamma a Immagini LEggero (AGILE) mission
• dedicated laboratory experiments and modelling

 

High-energy astrophysics

Research on cosmic Gamma-Ray Bursts (GRB).

The main question we want to answer:

• how can we use timing information to extract properties of the GRB progenitors?
• can we exploit the timing and spectral performance of ASIM for GRB science?

The tools we use:

• data from the Atmosphere-Space Interactions Monitor (ASIM) mission onboard the International Space Station (ISS)

 

High-energy detectors and systems

• we have built the gamma-ray detector for the ALOFT flight campaign
• we are building the Electrical Ground Support Equipment (EGSE) for X- and Gamma-ray Imaging Sensor (XGIS) of the Transient High-Energy Sky and Early Universe Surveyor (THESEUS), a medium-class mission candidate for the European Space Agency, currently in Phase A.

The latest news on my research, on the University of Bergen Website (Feb. 2025) 

Our work published in Nature in October 2024 has been picked up by more than 160 international media.

I regularly contributed to the news posted on the website of the Birkeland Centre for Space Science (2013 - 2023):

• August 2021: news on the new project funded by NFR
• June 2021: news on the ongoing collaboration between Italy and Norway on TGF science
• August 2019: news on the first meeting of the ISSI Team I coordinated (2019 - 2022)
• May 2019: news on the TGF International Research School

I also prepared the text for the BCSS annual report in the years 2017-2020, concerning the section related to Hard Radiation from Thunderstorms (all Annual Reports available from the BCSS homepage)

In June 2021 I prepared the text (in Italian) for the news on the ongoing collaboration between Italy and Norway on TGF, which has been posted on the website of the Italian Embassy in Oslo and on its social media accounts, and on the website of the Italian Ministry of Foreign Affairs dedicated to scientific diplomacy.

I also contributed, both with text and interviews, to the preparation of news (in Italian) published on ‘Media INAF’, the online public outreach journal of the Italian National Institute for Astrophysics:

• December 2019: news with interview on the first published results from ASIM
• March 2018: news with interview on the ASIM mission close to launch
• November 2017: news on a recent detection of a TGF from ground
• September 2010: news on the first localization of TGFs in gamma-rays (I am first author of the paper)

 

Bachelor / Master course responsibilities:

• 2024 –          PHYS251 The Near Earth Space, department of Physics and Technology, University of Bergen, Norway (main course responsible, 10 ECTS)
• 2016 –           PHYS113 Mechanics II and Thermodynamics, department of Physics and Technology, University of Bergen, Norway (main course responsible, 10 ECTS)

 

Supervisor / co-supervisor of the following PhD Thesis:

• Ingrid Bjørge-Engeland, The connection between lightning currents, TGF intensities and Elves, University of Bergen, Norway, 2024.
• Chris A. Skeie, Aircraft and spacecraft observations of high-energy radiation associated with lightning leaders, University of Bergen, Norway, 2022.
• Anders Lindanger, Spectral Analysis of Terrestrial Gamma-ray Flashes and Their Connection to Lightning Discharges, University of Bergen, Norway, 2022.
• Carolina Maiorana, Characteristics and Meteorological Environment of Terrestrial Gamma-ray Flashes, University of Bergen, Norway, 2021.
• Alessandra Tiberia, High-energy radiation from thunderclouds: on the relationships between terrestrial gamma-ray flashes and cloud structure, University of Ferrara, Italy, 2019.
• Alessandro Ursi, Short-duration gamma-ray transients Detection of Short Hard Bursts and Terrestrial Gamma-ray Flashes by the AGILE satellite, Sapienza University of Rome, Italy, 2016.

 

Supervisor of the following Master Thesis:

• Andreas Ramsli, Observation of cosmic Gamma-Ray Bursts with the ASIM mission onboard the International Space Station, University of Bergen, Norway, 2023.
• Anders Lindanger, Search for Terrestrial Gamma-ray Flashes in AGILE data by correlation with ground-based lightning measurements, University of Bergen, Norway, 2018.
• Alessandro Ursi, A search for Terrestrial Gamma-Ray Flashes in the BeppoSAX Gamma-Ray Burst Monitor data archive, University of Ferrara, Italy, 2013.

 

Contribution to research schools:

• 2024   invited teacher at the 1^st International School on Satellite Meteorology (ISSM), 2-6 Sep. 2024, Naples, Italy.
• 2019    Co-organizer and teacher at the Birkeland Centre Research School “Atmospheric Electricity and Hard Radiation from Thunderclouds”, University of Bergen, Norway

2025

• David Alexandre Stephan Sarria; Nikolai Østgaard; Ingrid Bjørge-Engeland et al. (2025). Spectral Analysis of Flickering Gamma-Ray Flashes Observed During the ALOFT 2023 Campaign. (external link)
• Martino Marisaldi (2025). What to do after ALOFT?. (external link)
• Martino Marisaldi (2025). Testing the hypothesis of lightning initiation by runaway air breakdown with ALOFT data. (external link)
• Vegard Gjerde; Martino Marisaldi; Kjellmar Oksavik et al. (2025). Mandatory retrieval test to incentivize retrieval practice of physics principles. (external link)
• Timothy J. Lang; Nikolai Østgaard; Martino Marisaldi et al. (2025). Hunting for Gamma Rays above Thunderstorms: The ALOFT Campaign. (external link)

2016

• A Ursi; Martino Marisaldi; M Tavani et al. (2016). Detection of multiple terrestrial gamma-ray flashes from thunderstorm systems. (external link)
• Fanchao Lyu; Steven A. Cummer; Michael Briggs et al. (2016). Ground detection of terrestrial gamma ray flashes from distant radio signals. (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 double RHESSI TGFs. (external link)
• Andrey Mezentsev; Nikolai Østgaard; Thomas Gjesteland et al. (2016). Radio emissions from double RHESSI TGFs. (external link)
• Nikolai Østgaard; Brant Edward Carlson; Ragnhild Schrøder Nisi et al. (2016). Relativistic electrons from sparks in the laboratory. (external link)
• Thomas Gjesteland; Nikolai Østgaard; Martino Marisaldi et al. (2016). Stereo Observations of Terrestrial Gamma-ray Flashes. (external link)

2023

• Martino Marisaldi (2023). The scientific payload of the ALOFT mission to chase Terrestrial Gamma-ray Flashes and gamma-ray glows. (external link)
• Martino Marisaldi (2023). Terrestrial Gamma-ray Flash observations by the ALOFT flight campaign. (external link)
• Lasse Skaaning Husbjerg; Torsten Neubert; Olivier Chanrion et al. (2023). Characterization of Thunderstorm Cells Producing Observable Terrestrial Gamma-Ray Flashes. (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)
• A. Coleman; J. Eser; E. Mayotte et al. (2023). Ultra high energy cosmic rays The intersection of the Cosmic and Energy Frontiers. (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)

2024

• Martino Marisaldi (2024). A novel view of gamma-ray glows from the ALOFT 2023 flight campaign. (external link)
• Nikolai Østgaard; Andrey Mezentsev; Martino Marisaldi et al. (2024). Flickering gamma-ray flashes, the missing link between gamma glows and TGFs. (external link)
• Martino Marisaldi (2024). Gamma-ray emission from thunderstorms. (external link)
• Ingrid Bjørge-Engeland; Nikolai Østgaard; David Alexandre Stephan Sarria et al. (2024). Evidence of a New Population of Weak Terrestrial Gamma-Ray Flashes Observed From Aircraft Altitude. (external link)
• Martino Marisaldi (2024). The Novel View of Gamma-Ray Active Thunderclouds from the ALOFT Flight Campaign. (external link)
• Martino Marisaldi; Nikolai Østgaard; Andrey Mezentsev et al. (2024). Highly dynamic gamma-ray emissions are common in tropical thunderclouds. (external link)
• Ingrid Bjørge-Engeland; Nikolai Østgaard; Martino Marisaldi et al. (2024). High Peak Current Lightning and the Production of Elves. (external link)
• Andrey Mezentsev; Nikolai Østgaard; Martino Marisaldi et al. (2024). Discerning TGF and Leader Current Pulse in ASIM Observation. (external link)

2019

• Alessandro Ursi; Martino Marisaldi; Marco Tavani (2019). Detection of terrestrial gamma-ray flashes with the AGILE/MCAL. (external link)
• Alessandro Ursi; Marco Tavani; Francesco Verrecchia et al. (2019). A New AGILE MCAL Configuration to Detect Gamma-Ray Bursts and Sub-threshold Events in the Multimessenger Era. (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)
• Alessandro Ursi; Martino Marisaldi; Stefano Dietrich et al. (2019). Analysis of Thunderstorms Producing Terrestrial Gamma Ray Flashes With the Meteosat Second Generation. (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)
• Nikolai Østgaard; Torsten Neubert; Victor Reglero et al. (2019). First 10 Months of TGF Observations by ASIM. (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)
• Alessandra Tiberia; Stefano Dietrich; Federico Porcu et al. (2019). Gamma ray storms: preliminary meteorological analysis of AGILE TGFs: Meteorology of AGILE TGF observations. (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; Hugh J. Christian; J. Eric Grove et al. (2019). Gamma Ray Glow Observations at 20-km Altitude. (external link)

2021

• Anders Lindanger; Martino Marisaldi; David Alexandre Stephan Sarria et al. (2021). Spectral Analysis of Individual Terrestrial Gamma-ray Flashes Detected by ASIM. (external link)
• A.J. Castro-Tirado; Nikolai Østgaard; E. Göǧüş et al. (2021). Very-high-frequency oscillations in the main peak of a magnetar giant flare. (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)
• Nikolai Østgaard; S.A. Cummer; Andrey Mezentsev et al. (2021). Simultaneous Observations of EIP, TGF, Elve, and Optical Lightning. (external link)
• Marco Tavani; C. Casentini; Alessandro Ursi et al. (2021). An X-ray burst from a magnetar enlightening the mechanism of fast radio bursts. (external link)
• Alessandra Tiberia; F. Porcú; Martino Marisaldi et al. (2021). GPM-DPR Observations on TGFs Producing Storms. (external link)
• Alessandra Tiberia; Alessandra Mascitelli; Leo Pio D’adderio et al. (2021). Time evolution of storms producing terrestrial gamma-ray flashes using era5 reanalysis data, gps, lightning and geo-stationary satellite 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)
• Carolina Maiorana; M. Marisaldi; Martin Füllekrug et al. (2021). Observation of Terrestrial Gamma-Ray Flashes at Mid Latitude. (external link)

2020

• C. Casentini; F. Verrecchia; Marco Tavani et al. (2020). AGILE Observations of Two Repeating Fast Radio Bursts with Low Intrinsic Dispersion Measures. (external link)
• Torsten Neubert; Nikolai Østgaard; Victor Reglero et al. (2020). A terrestrial gamma-ray flash and ionospheric ultraviolet emissions powered by lightning. (external link)
• Anders Lindanger; Martino Marisaldi; Carolina Maiorana et al. (2020). The 3rd AGILE Terrestrial Gamma Ray Flash Catalog. Part I: Association to Lightning Sferics. (external link)
• A. Ursi; M. Tavani; D.D. Frederiks et al. (2020). AGILE and Konus-Wind Observations of GRB 190114C: The Remarkable Prompt and Early Afterglow Phases. (external link)
• V. Fioretti; A. Bulgarelli; M. Tavani et al. (2020). AGILESim: Monte Carlo Simulation of the AGILE Gamma-Ray Telescope. (external link)
• Carolina Maiorana; Martino Marisaldi; Anders Lindanger et al. (2020). The 3rd AGILE Terrestrial Gamma-ray Flashes Catalog. Part II: Optimized Selection Criteria and Characteristics of the New Sample. (external link)

2017

• A Ursi; P Sano; D Casella et al. (2017). A pipeline to link meteorological information and TGFs detected by AGILE. (external link)
• F. Verrecchia; M Tavani; I. Donnarumma et al. (2017). AGILE Observations of the Gravitational-wave Source GW170817: Constraining Gamma-Ray Emission from an NS-NS Coalescence. (external link)
• Francesco Verrecchia; Marco Tavani; Alessandro Ursi et al. (2017). AGILE observations of the gravitational-wave source GW170104. (external link)
• Alessandro Ursi; Cristiano Guidorzi; Martino Marisaldi et al. (2017). Terrestrial gamma-ray flashes in the BeppoSAX data archive. (external link)
• Martino Marisaldi; M Galli; A Ursi et al. (2017). On the high-energy spectral component of TGFs detected by AGILE. (external link)
• Benjamin P. Abbott; R Abbott; TD Abbott et al. (2017). Multi-messenger observations of a binary neutron star merger. (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)
• Martino Marisaldi; Nikolai Østgaard; Kjetil Albrechtsen et al. (2017). A Synergic Approach to the Study of TGFs and Energetic Radiation from Thunderstorms. (external link)
• Kevin C. Hurley; Rafail L. Aptekar; Sergey V. Golenetskii et al. (2017). The interplanetary network supplement to the Second Fermi GBM catalog of cosmic gamma-ray bursts. (external link)
• Kjetil Albrechtsen; Nikolai Østgaard; Martino Marisaldi et al. (2017). Estimating the global production rate of TGFs. (external link)
• A De Angelis; V Tatischeff; M Tavani et al. (2017). The e-ASTROGAM mission Exploring the extreme Universe with gamma rays in the MeV - GeV range. (external link)
• A Ursi; Martino Marisaldi; Marco Tavani et al. (2017). Detection of terrestrial gamma-ray flashes with the AGILE satellite. (external link)
• Nikolai Østgaard; Martino Marisaldi; Pavlo Kochkin et al. (2017). How should we define terrestrial gamma-ray flashes?. (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)
• Nikolai Østgaard; Hugh J. Christian; Eric Grove et al. (2017). Gamma-ray observations at 20 km altitude above thunderstorms. (external link)

2018

• PW Cattaneo; A Rappoldi; A Argan et al. (2018). Calibration of AGILE-GRID with On-ground Data and Monte Carlo Simulations. (external link)
• Alessandro De Angelis; Vincent Tatischeff; Isabelle A. Grenier et al. (2018). Science with e-ASTROGAM: A space mission for MeV–GeV gamma-ray astrophysics. (external link)
• Vincent Tatischeff; Alessandro De Angelis; Marco Tàvani et al. (2018). The e-ASTROGAM gamma-ray space observatory for the multimessenger astronomy of the 2030s. (external link)
• Lorenzo Amati; Paul O'Brien; Diego Gotz et al. (2018). The THESEUS space mission concept: science case, design and expected performances. (external link)

2013

• Thomas Gjesteland; Nikolai Østgaard; Martino Marisaldi et al. (2013). Terrestrial Gamma ray Flashes observed over low clod tops. (external link)
• Thomas Gjesteland; Nikolai Østgaard; Martino Marisaldi et al. (2013). Unusual bright TGF from low cloud tops over the Mediterranean sea. (external link)

2022

• A. Ursi; M. Romani; G. Piano et al. (2022). AGILE Observations of GRB 220101A: A "new Year's Burst" with an Exceptionally Huge Energy Release. (external link)
• D.S. Svinkin; K. Hurley; A.V. Ridnaia et al. (2022). The Second Catalog of Interplanetary Network Localizations of Konus Short-duration Gamma-Ray Bursts. (external link)
• Michael J. Peterson; Timothy J. Lang; Timothy Logan et al. (2022). New WMO Certified Megaflash Lightning Extremes for Flash Distance and Duration Recorded from Space. (external link)
• Ingrid Bjørge-Engeland; Nikolai Østgaard; Andrey Mezentsev et al. (2022). Terrestrial Gamma-Ray Flashes With Accompanying Elves Detected by ASIM. (external link)
• A. Ursi; M. Romani; F. Verrecchia et al. (2022). The Second AGILE MCAL Gamma-Ray Burst Catalog: 13 yr of Observations. (external link)
• 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)
• 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)

2026

• Øystein Håvard Færder; Nikolai Grigorievich Lehtinen; D. Sarria et al. (2026). Numerical Parameter‐Space Studies of Various Types of Thundercloud Gamma‐Ray Emissions. (external link)

2014

• Martino Marisaldi; Fabio Fuschino; Marco Tàvani et al. (2014). Properties of terrestrial gamma ray flashes detected by AGILE MCAL below 30 MeV. (external link)

2015

• Martino Marisaldi; Andrea Argan; Alessandro Ursi et al. (2015). Enhanced detection of terrestrial gamma-ray flashes by AGILE. (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)
• Ferran Fabró; Joan Montanyà; Martino Marisaldi et al. (2015). Analysis of global Terrestrial Gamma Ray Flashes distribution and special focus on AGILE detections over South America. (external link)

See a complete overview of publications in Cristin.

I am coauthor of 142 refereed publications, with an H-Index of 40 (Web of Science, accessed 12/09/2024).

My top research publications are the following

1. M. Marisaldi, N. Østgaard, A. Mezentsev, et al. (2024), Highly dynamic gamma-ray emissions are common in tropical thunderclouds, Nature, 634, 57, DOI: 10.1038/s41586-024-07936-6.
2. N. Østgaard, A. Mezentsev, M. Marisaldi, et al. (2024), Flickering Gamma-Ray Flashes, the Missing Link between Gamma Glows and TGFs, Nature, 634, 53, DOI: 10.1038/s41586-024-07893-0.
3. A. Castro-Tirado, N. Østgaard, E. Gögüs, et al. (2021), Very-high-frequency oscillations in the main peak of a magnetar giant flare, Nature 600, https://doi.org/10.1038/s41586-021-04101-1 
4. M. Marisaldi, et al. (2019), On the high-energy spectral component and fine time structure of terrestrial gamma-ray flashes, J. Geophys. Res. (Atmospheres), 124. https://doi.org/10.1029/2019JD030554 
5. M. Marisaldi, et al. (2015), Enhanced detection of terrestrial gamma-ray flashes by agile. Geophys. Res. Lett., 42(21):9481–9487, https://doi.org/10.1002/2015GL066100 
6. M. Marisaldi, F. Fuschino, M. Tavani, et al. (2014) Properties of terrestrial gamma ray flashes detected by AGILE MCAL below 30 MeV. J. Geophys. Res. (Space Physics), 119:1337–1355, https://doi.org/10.1002/2013JA019301 
7. M. Tavani, M. Marisaldi, C. Labanti, et al. (2011), Terrestrial Gamma-Ray Flashes as Powerful Particle Accelerators. Physical Review Letters, 106(1):018501, https://doi.org/10.1103/PhysRevLett.106.018501 
8. M. Marisaldi, et al. (2010), Gamma-Ray Localization of Terrestrial Gamma-Ray Flashes. Physical Review Letters, 105(12):128501, https://doi.org/10.1103/PhysRevLett.105.128501 
9. M. Marisaldi, et al. (2010), Detection of terrestrial gamma ray flashes up to 40 MeV by the AGILE satellite. J. Geophys. Res. (Space Physics), 115:0, https://doi.org/10.1029/2009JA014502
10. C. Labanti, M. Marisaldi, et al. (2009), Design and construction of the Mini-Calorimeter of the AGILE satellite. Nucl. Instrum. and Meth. in Phys. Res. A, 598:470–479, https://doi.org/10.1016/j.nima.2008.09.021 

 

A complete list of my publications with metrics can be retrieved from the Astrophysics Data System (ADS). 

Below are my publications listed in the CRIStin database.

 

Active projects:

• 2024 – 2026 Principal Investigator, Conceptual design and prototyping of the Electrical Ground Support Equipment for THESEUS XGIS. Funding: European Space Agency. 
• 2023 – 2025 Principal Investigator, From lightning to the dawn of time: study of the timing structure of cosmic Gamma-Ray Bursts with the Atmosphere-Space Interactions Monitor. Funding: Peder Sather Center for Advanced Study. Collaboration project with the Astronomy Department at the University of Berkeley, USA. 
• 2021 – 2026 Principal Investigator, TGF Airborne Observatory (TAO): Understanding the link between lightning, terrestrial gamma-ray flashes and gamma-ray glows. Funding: Research Council of Norway. Partly funding the ALOFT flight campaign. 

 

Past projects as Principal Investigator:

• 2019 - 2022. Principal Investigator of the International Team 'Understanding the properties of the Terrestrial Gamma-ray Flash population' at the International Space Science Institute (ISSI), Bern, Switzerland.
• 2015 – 2016 International fellowship: Fulbright Research Scholar (6 months) at Duke University, Department of Electrical and Computing Engineering, NC, USA. 
• 2012 – 2014 Principal Investigator, ‘PICO: Picosecond Cherenkov Observatory’. Funder: National Institute for Astrophysics (INAF), Italy. R&D project for the exploitation of ultra-fast solid-state detectors for high-energy astrophysics in the TeV band.