he problem of how lightning is initiated inside thunderclouds is probably one of the biggest mysteries in the atmospheric sciences. Recently established high energy processes in the atmosphere, i.e. Terrestrial Gamma Flashes (TGF) – brief bursts of gamma rays observed by orbiting gamma ray observatories and Thunderstorm Ground Enhancements (TGEs) – sizable long-lasting fluxes of electrons, gamma rays and neutrons detected on Earth’s surface are correlated with thunderstorms.

However, the relationship among thundercloud electrification, lightning activity, and wideband radio emission and enhanced particle fluxes have not been yet unambiguously established. One of the most intriguing opportunities opened by the observation of the high-energy processes in the atmosphere is their relation to lightning initiation and propagation.

With the objective to discuss these high-energy phenomena, the 5 th annual conference on Thunderstorms and Elementary Particle Acceleration (TEPA) was held at the Nor Amberd International Conference Center of the Yerevan Physics Institute (YerPhI) in Armenia. The Cosmic Ray Division of the YerPhI and Skobeltsyn Institute of Nuclear Physics of Moscow State University organized the workshop; YerPhI and the Armenian State Committee of Science sponsored it. Thirty scientists and students from the United States, Japan, France, Germany, Israel, Russia, and Armenia attended.

Presentations focused on observations and models of high-energy emissions in thunderclouds; on the termination of particle fluxes by lightning; multivariate observations of thunderstorms from the Earth’s surface and from space; radio emissions produced by atmospheric discharges and particle fluxes; the influence of the Extensive Air Showers (EASes) on lightning initiation and others.

In March, 2016 the Proceedings of symposium has been printed by the TIGRAN METS printing house. The online version of the manual can be found at http://www.yerphi.am/images/tepa-2015-21march-low.pdf

More details can be found in the supplemental information in the symposia sitehttp://crd.yerphi.am/Conferences/tepa2015/presentation The next TEPA-2016 symposium is scheduled on October 3-7 in Nor Amberd international conference center.