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The effect of direct electron‐positron pair production on relativistic feedback rates
Author(s) -
Vodopiyanov I. B.,
Dwyer J. R.,
Cramer E. S.,
Lucia R. J.,
Rassoul H. K.
Publication year - 2015
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
eISSN - 2169-9402
pISSN - 2169-9380
DOI - 10.1002/2014ja020415
Subject(s) - physics , positron , pair production , electron , electric field , atomic physics , gamma ray , production (economics) , field (mathematics) , nuclear physics , flux (metallurgy) , quantum mechanics , mathematics , pure mathematics , economics , macroeconomics , materials science , metallurgy
Runaway electron avalanches developing in thunderclouds in high electric field become self‐sustaining due to relativistic feedback via the production of backward propagating positrons and backscattered X‐rays. To date, only positrons created from pair production by gamma rays interacting with the air have been considered. In contrast, direct electron‐positron pair production, also known as “trident process,” occurs from the interaction of energetic runaway electrons with atomic nuclei, and so it does not require the generation of a gamma ray mediator. The positrons produced in this process contribute to relativistic feedback and become especially important when the feedback factor value approaches unity. Then the steady state flux of runaway electrons increases significantly. In certain cases, when the strong electrostatic field forms in a narrow area, the direct positrons become one of processes dominating relativistic feedback. Calculations of the direct positron production contribution to relativistic feedback are presented for different electric field configurations.