Михаил Зелёный

Relativistic runaway electron avalanches (RREAs) are generally accepted as a source of thunderstorms gamma ray radiation. Avalanches can multiply in the electric field via the relativistic feedback mechanism based on processes with gamma rays and positrons. This study shows that a non-uniform electric field geometry can lead to the new RREAs multiplication mechanism—“reactor feedback,” due to the exchange of high-energy particles between different accelerating regions within a thundercloud. A new method for the numerical simulation of RREA dynamics within heterogeneous electric field structures is proposed. Under the assumption that reactor feedback can produce a terrestrial gamma ray flash (TGF), necessary conditions for TGF occurrence in the system with the reactor feedback are derived using the developed analytical description and the numerical simulation. Observable properties of TGFs influenced by the proposed mechanism are discussed.