2023-10-24 06:31:51

Fifteen years of research in High-energy Physics in the Atmosphere: the number of citations to the first 2 HEPA publications reached 400

Mt. Aragats, located 3200 meters above sea level, near the southern peak on the beach of the large Kari Lake, is home to one of the world's biggest high-altitude cosmic-ray research stations. Physicists have been studying cosmic ray fluxes on Mt. Aragats since 1942 using various particle detectors such as mass spectrometers, calorimeters, transition radiation detectors, and particle detector arrays detecting particle cascades initiated by protons and nuclei accelerated in most explosions in the galaxy. The latest research at Mt. Aragats focuses on the origin and acceleration mechanisms of the galactic cosmic rays, space weather, and solar proton accelerators. In 2008, after finishing experiments with galactic and solar cosmic rays High-energy physics in the atmosphere (HEPA) became the main topic of CRD research. Since 2008, particle detectors of the Aragats Space Environmental Center (ASEC) have continuously registered fluxes of charged and neutral particles using various particle detectors located on the slopes of Aragats. Thunderstorm activity on Aragats is extreme in May - June. Thunderclouds are usually below the southern peak (i.e., not higher than 500 m above ground level) and sometimes only 25–50 m above the station. As a result, the most energetic TGEs can contain many avalanche electrons, allowing recovery of the electron energy spectrum. The primary research goal, TGE research, was established with continuous monitoring of cosmic rays for 15 years, and just the first papers published by CRD scientists in 2010 and 2011 already contain valuable information on new physical phenomena, with a number of citations reaching now 400 (according to Google Scholar). The main results of CRD physicists in HEPA include:

  • Registration of more than 600 TGEs minute-long fluxes of electrons, gamma rays, and rarely neutrons [3].
  • Measurement of energy spectra of electrons and gamma rays [4,5]
  • Discovery of Radon circulation, muon-stopping, and positron acceleration effects.
  • Revealing the charge structure of the thundercloud, estimating the maximum potential drop above Aragats and
Lomnicky Stit research stations, and clarifying the horizontal extent of atmospheric electric fields
  • Revealing the cloud charge structure and the role of lightning discharges on particle fluxes.
  • Performing simulations of runaway process, verifying it with recovered energy spectra and count rates of ASEC detectors.  
  • Clarifying the influence of atmospheric electric fields on estimating the energy of galactic cosmic rays by large surface arrays.
  • Performing the first TGE registration campaign on the highest mountain tops of Eastern Europe, Germany,
and Armenia by SEVAN detectors network. 
These and other results, published in 80 papers, have helped to understand the mechanism of TGE origination
in strong atmospheric electric fields establishing the HEPA scientific discipline.

Aragats research station of Yerevan Physics Institute near Kare Lake and South peak of Aragats


  1. Chilingarian, A. Daryan, K. Arakelyan, A. Hovhannisyan, B. Mailyan, L. Melkumyan, G. Hovsepyan, S. Chilingaryan,
A. Reymers, and L. Vanyan, Ground-based observations of thunderstorm-correlated fluxes of high-energy electrons, gamma rays, and neutrons, Phys. Rev. D 82, 043009 (2010). 
  1. Chilingarian A., Hovsepyan G., and Hovhannisyan A., Particle bursts from thunderclouds: Natural particle accelerators above our heads, Physical Review D 83, 062001 (2011).
  2. Chilingarian, G. Hovsepyan, D. Aslanyan, T. Karapetyan, Y. Khanikyanc, L.Kozliner, B. Sargsyan, S.Soghomonyan, S.Chilingaryan, D.Pokhsraryan,
and M.Zazyan (2022) Thunderstorm Ground Enhancements: Multivariate analysis of 12 years of observations, Physical Review D 106, 082004 (2022). 
  1. Chilingarian, G. Hovsepyan, T. Karapetyan, D. Aslanyan, S. Chilingaryan, and B. Sargsyan, Genesis of thunderstorm ground enhancements, Physical Review D 107, 102003 (2023).
  2. Chilingarian, A., Hovsepyan, G., Aslanyan, D., Karapetyan, T., Sargsyan, B., & Zazyan, M. (2023).
TGE electron energy spectra: Comment on “Radar diagnosis of the thundercloud electron accelerator” by E. Williams et al. (2022). Journal of Geophysical Research: Atmospheres, 128, e2022JD037309