- 1University of Bergen, Birkeland Centre for Space Science, Hard Radiation group , Bergen, Norway (david.sarria.89@gmail.com)
- 2NASA Marshall Space Flight Center, Huntsville, USA
- 3New Mexico Institute of Mining and Technology, USA
- *A full list of authors appears at the end of the abstract
In July 2023, the ALOFT flight campaign deployed an ER-2 research aircraft that flew at 20 km altitude above thunderstorms, carrying an extensive suite of instruments. The campaign observed numerous gamma-ray glows exhibiting complex and highly dynamic morphologies (Marisaldi et al. 2024). This study focuses on two specific glow events recorded on July 29th, 2023, between 20:30:20 and 20:31:40 UTC over Florida. By combining Monte Carlo simulations with observations from hard-radiation instruments and ground-based interferometers, we can estimate the multiplication factor required, based on cosmic-ray secondary electrons, to produce gamma-ray glows of the observed magnitude (exceeding 7 times the background level on the ALOFT-BGO detector).
Our analysis reveals multiplication factors of seed electrons (cosmic-ray secondaries) significantly exceeding a factor 5000, occurring multiple times and persisting for periods of several seconds. According to previous studies (Dwyer et al. 2007; Kelley et al. 2015), such high multiplication factors indicate substantial contribution from the Relativistic Feedback Discharge mechanism. Using the methodology established by Kelley et al. (2015), we estimated that the discharge currents resulting from the relativistic process during high-intensity phases of the glow could range in the tens to hundreds of amperes. These values substantially exceed those previously reported by Kelley et al. (2015) and could be large enough to significantly influence the thunderstorm's charging rate.
This study provides evidence that the Relativistic Runaway Electron Avalanche process, amplified by the relativistic feedback mechanism, could compete with conventional discharge mechanisms in certain thunderstorm conditions.
References:
- Marisaldi, M., Østgaard, N., Mezentsev, A., Lang, T., Grove, J. E., Shy, D., Heymsfield, G. M., Krehbiel, P., Thomas, R. J., Stanley, M., Sarria, D., Schultz, C., Blakeslee, R., Quick, M. G., Christian, H., Adams, I., Kroodsma, R., Lehtinen, N., Ullaland, K., Yang, S., Qureshi, B. H., Søndergaard, J., Husa, B., Walker, D., et al. (2024). Highly dynamic gamma-ray emissions are common in tropical thunderclouds. Nature. https://doi.org/10.1038/s41586-024-07936-6
- Kelley, N. A., Smith, D. M., Dwyer, J. R., Splitt, M., Lazarus, S., Martinez-McKinney, F., Hazelton, B., Grefenstette, B., Lowell, A., & Rassoul, H. K. (2015). Relativistic electron avalanches as a thunderstorm discharge competing with lightning. Nature Communications. https://doi.org/10.1038/ncomms8845
- Dwyer, J. R. (2007). Relativistic breakdown in planetary atmospheres. Physics of Plasmas. https://doi.org/10.1063/1.2709652
Adams, Ian S. ian.s.adams@nasa.gov Bitzer, Phillip M. bitzerp@uah.edu Blakeslee, Richard rich.blakeslee@nasa.gov Christian, Hugh hugh.christian@gmail.com Cohen, Morris B. mcohen@gatech.edu Cummer, Steve cummer@duke.edu Engeland, Ingrid ingrid.engeland@uib.no Fuglestad, Anders anders.fuglestad@student.uib.no Fullekrug, Martin eesmf@bath.ac.uk Grove, J. Eric eric.grove@nrl.navy.mil Heymsfield, Gerald M. gerald.m.heymsfield@nasa.gov Krehbiel, Paul krehbiel@ibis.nmt.edu Kroodsma, Rachael A. rachael.a.kroodsma@nasa.gov Lang, Timothy J. timothy.j.lang@nasa.gov Lehtinen, Nikolai nikolai.lehtinen@uib.no Longenbaugh, Randy S. rslonge@sandia.gov Marisaldi, Martino martino.marisaldi@uib.no Mezentsev, Andrey andrey.mezentsev@uib.no Montaña Puig, Joan joan.montanya@upc.edu Østgaard, Nikolai nikolai.ostgaard@uib.no Pazos, Marni marni@unam.mx Pu, Yunjiao yunjiao.pu@duke.edu Qureshi, Bilal Hasan bilal.qureshi@uib.no Sarria, David david.sarria@uib.no Schultz, Christopher J. christopher.j.schultz@nasa.gov Shy, Daniel daniel.shy.ctr@nrl.navy.mil Søndergaard, Jens jens.sondergaard@uib.no Søndergaard, Jens jls@stmas.no Stanley, Mark A. sparky@mark-stanley.name Quick, Mason mason.quick@nasa.gov Ullaland, Kjetil kjetil.ullaland@uib.no Van Der Velde, Oscar oscar.van.der.velde@upc.edu Velosa, Camilo Younes cyounesv@unal.edu.co Yang, Shiming shiming.yang@uib.no
How to cite: Sarria, D., Østgaard, N., Marisaldi, M., Mezentsev, A., Lehtinen, N., Bjørge-Engeland, I., Fuglestad, A., Lang, T. J., and Stanley, M. A. and the The ALOFT Team: Evidence of gamma-ray glows observed in the relativistic feedback regime during the ALOFT 2023 flight campaign, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-16240, https://doi.org/10.5194/egusphere-egu25-16240, 2025.
