CRD Annual report 2021 /main achievements, directions of research/

Last decade the research in high-energy physics in the atmosphere (HEAP) was mostly concentrated on measuring the particle fluxes from the electrified atmosphere (thunderstorm ground enhancements, TGEs, and Terrestrial gamma flashes, TGFs) and revealing their origin. Afterward, in 2021 started the research of the atmospheric electric fields with particle fluxes traversing thunderstorms and registering on the earth’s surface with particle spectrometers, i.e., we use particle fluxes for screening of thunderous atmosphere (like X-ray screening). The new approach gives very interesting results, sometimes contradicting the common knowledge on the vertical profile of atmospheric electric field, however, supported by the exact methods of particle physics and well-established theories of the electromagnetic interactions.

First of all, it was establishing of a working model of electron acceleration in the strong atmospheric electric fields [1-3]. Comparison of measured on Aragats and simulated fluxes of electrons and gamma rays (of course with simplified models of the vertical electric field profile) demonstrates that relativistic runaway electron avalanches can originate TGEs with rather a broad diapason of parameters. Then using the largest TGEs obtained on Aragats and Lomnicky Stit we estimated the maximum achievable potential drop (voltage) on these summits to be consequently 300 and 500 MV [4,5]. Afterward, we use the modulation of the “muon beams” by strong atmospheric electric fields to investigate how discovered “muon stopping effect” can be used for describing the disturbances of the atmospheric electric field [6]. Finally, profiting from the 24/7 operation of the Aragats Solar neutron spectrometer (ASNT), we develop a methodology to estimate the vertical profile of electric fields in thunderclouds [7]. The correlation analysis of the TGEs and the distances to the lightning discharges allows deducing that the TGE particle flux is much higher than was anticipated. Many species of elementary particles are born in the terrestrial atmosphere by high-energy protons and fully-stripped nuclei accelerated at exotic galactic sources. During thunderstorms, to this more-or-less constant flux are added electrons and gamma rays from the most powerful natural electron accelerator operated in the electrifying atmosphere.

The particle flux in the thunderous atmosphere, most of which reach the earth’s surface comprises ≈1018 particles with energies above 100 keV per second [8]. This abundant radiation can influence terrestrial claymate and global change issues. The synergy of cosmic ray and atmospheric physics, which can become a leading direction in atmospheric physics research allows explaining all particle types of particle bursts within one framework, i.e., as consequences of extensive air showers fluxes [9]. Spectra measured 2019-2021, allows to discovery very large electric field (up to 200 kV/m) nearby the earth’s surface (50-150m), which can have crucial consequences on the safety of launching rockets and operation of the aircraft during thunderstorms.

The operation of the SEVAN network in 2021 reveals brings new exciting results. The SEVAN detector on Lomnicky Sˇtít (Slovakia) on September 12 measured in 2021 a 500% enhancement of low energy thunderstorm ground enhancements (TGE) particle flux. The world-largest TGE, with particle fluxes exceeding the background 100-times, also was measured by the Slovakian SEVAN in 2017. As we mentioned already, using measured by SEVAN modules fluxes of muon and gamma rays, the maximum values of the potential difference in thunderclouds were estimated, and the muon deficit effect was confirmed; a new method to determine the charge structure in thunderclouds was established. Croatian SEVAN detector was used in the study of a relationship between the heliospheric magnetic field, atmospheric electric field, lightning activity, and secondary cosmic ray’s flux. There was mentioned the superiority of the SEVAN detector due to its ability to distinguish between different particles and threshold energies. Obtained results were reported on the International Cosmic Ray Conference (ICRC, Berlin, 2021) and European Geophysical Union (EGU, Vienna, 2021), and other meetings.

Fluxes of electrons, photons, and muons and also weather parameters are continuously monitored at all sites (different latitudes, longitudes, altitudes) and entered the CRD databases. Physicists from all countries can use the multivariate visualization and correlation analyses (provided by the ADEI platform at CRD servers) for their own and collaborating work. A new type of accumulated TGE data (Mendeley datasets) was introduced in 2021, allowing the HEPA community to use TGE databases for using particle beams for the investigation of a wide variety of atmospheric physics problems [10-13].

References 2021

1. А.Chilingarian, High Energy Physics in the Earth’s Atmosphere, Природа 3, 11, 2021.
2. Ashot Chilingarian, Progress of High-Energy Physics in Atmosphere achieved with the implementation of particle physics and nuclear spectroscopy methods, 2021, 37th International Cosmic Ray Conference, DOI: 10.22323/1.395.0366
3. A. Chilingarian, G. Hovsepyan, E. Svechnikova, and M. Zazyan, Electrical structure of the thundercloud and operation of the electron accelerator inside it, Astroparticle Physics 132 (2021) 102615
4. A.Chilingarian, G. Hovsepyan, G.Karapetyan, and M.Zazyan, Stopping muon effect and estimation of intracloud electric field, Astroparticle Physics 124 (2021) 102505.
5. A.Chilingarian, T.Karapetyan, H.Hovsepyan, et. al., Maximum strength of the atmospheric electric field, PRD, 2021, 103, 043021 (2021).
6. Chilingarian, A., Hovsepyan, G., & Zazyan, M. (2021). Muon tomography of charged structures in the atmospheric electric field. Geophysical Research Letters, 48, e2021GL094594.
7. A.Chilingarian, G. Hovsepyan, and M. Zazyan, Measurement of TGE particle energy spectra: An insight in the cloud charge structure, Europhysics letters (2021), 134 (2021) 6901, 5075/ac0dfa
8. A. Chilingarian, G. Hovsepyan, Synergy of the Cosmic Ray and High Energy Atmospheric Physics, arXiv:2111.12053 [hep-ex], submitted to PRD
9. A.Chilingarian, G. Hovsepyan, M.Zazyan, Atmospheric electricity and thunderstorm ground enhancements, arXiv:2112.08721 [], submitted to EPL.
10. Soghomonyan, Suren; Chilingarian, Ashot ; Khanikyants, Yeghia (2021), “Dataset for Thunderstorm Ground Enhancements terminated by lightning discharges”, Mendeley Data, V1, doi: 10.17632/p25bb7jrfp.1
11. Soghomonyan, Suren; Chilingarian, Ashot (2021), “Thunderstorm ground enhancements abruptly terminated by a lightning flash registered both by WWLLN and local network of EFM-100 electric mills.”, Mendeley Data, V1, doi: 10.17632/ygvjzdx3w3.1
12. Chilingarian, Ashot, Hovsepyan, Gagik, Dataset for 16 parameters of ten thunderstorm ground enhancements (TGEs) allowing recovery of electron energy spectra and estimation the structure of the electric field above earth’s surface, Mendeley Data, V1, doi: 10.17632/tvbn6wdf85.2
13. Soghomonyan, Suren; Chilingarian, Ashot; Pokhsraryan, David (2021), “Extensive Air Shower (EAS) registration by the measurements of the multiplicity of neutron monitor signal”, Mendeley Data, V1, doi: 10.17632/43ndcktj3z.1
14. A. Chilingarian, D. Aslanyan, B. Sargsyan, On the origin of particle flux enhancements during winter months at Aragats, Physics Letters A 399 (2021) 127296
15. Svechnikova E.K., Ilin N.V., Mareev E.A., Chilingarian A., Characteristic features of the clouds producing thunderstorm ground enhancements, JGR Atmosphere, 2021, 126, e2019JD030895, doi:10.1029/2019JD030895.
16. A. Chilingarian, G.Hovsepyan, D.Aslanyan, T.Karapetyan, Y.Khanikyanc, L.Kozliner, B. Sargsyan, S.Soghomonyan, S.Chilingaryan and M.Zazyan, Thunderstorm Ground Enhancements: Multivariate analysis of 12 years observations, submitted to Phys. Rev. D, 2021.

Conferences 2021

European Geophysical Union meeting, EGU 21 Dates: 19-30 April 2021 Location: Göttingen, Germany, (vEGU21: Gather Online). Website Poster: Davit Aslanyan, et al., Catalog of TGEs observed at Aragats during 2008-2020
COST Action CA15211, Belgrade (hybrid meeting, at Geographical Institute “Jovan Cvijić” SASA, and remote via ZOOM). Dates: 1-3 March 2021 Website: Talk: Ashot Chilingarian: Circulation of radon progeny in the terrestrial atmosphere during thunderstorms
International Cosmic Ray Conference ICRC 37, Berlin Dates July 9-23 Website Tlak: A.Chilingarian, The progress of High-Energy Physics in Atmosphere (HEPA) achieved with particle physics and nuclear spectroscopy methods