On production of gamma rays and relativistic runaway electron avalanches from Martian dust storms

Abstract

Production of runaway electron avalanches and gamma rays originating inside Martian dust storms are studied using Monte Carlo simulations. In the absence of in situ measurements, we use theoretical predictions of electric fields inside dust storms. Electrons are produced through the relativistic runaway electron avalanches process, and energetic photons are results of the bremsstrahlung scattering of the electrons with the air. Characteristic lengths of the runaway electron avalanche for different electric fields and the energy spectrum of electrons are derived and compared to their terrestrial counterparts. It is found that it is possible for Martian dust storms to develop energetic electron avalanches and produce large fluxes of gamma ray photons similar to terrestrial gamma ray flashes from Earth's thunderstorms. The phenomenon could be called Martian gamma ray flash, and due to the very thin atmosphere on Mars, it can be observed by both ground‐based instruments or satellites orbiting the planet.

Runaway electrons in diffuse gas discharges

“…Runaway electrons are a fundamental physical phenomenon in natural [1][2][3][4][5][6] and laboratory discharges [7][8][9][10][11][12][13][14], including sparks over meter gaps [15][16][17][18], and in systems for controlled thermonuclear fusion [19][20][21]. The fact that runaway electrons do exist in discharges in the upper atmosphere was predicted by С.Т.R.…”

“…Reasoning that the maximum cross section of inelastic collisions falls on the electron energy ∼100 eV and decreases gradually as the energy increases to 1 MeV [2,15,22], each next collision with gas particles can provide a lower energy loss and the electron energy can increase up to eU m , where e is the electron charge and U m is the maximum gap voltage. The phenomenon of electron runaway has been studied by theorists since the last century [1][2][3][4][5][6][23][24][25][26] till now [27][28][29][30].…”

“…Some data on these studies can be found elsewhere [51][52][53]. By now, thousands of research papers are available on runaway electrons and x rays in different conditions, including those at low pressures and voltages [51][52][53], in meter gaps [15][16][17][18] and shorter [54][55][56][57][58], in different atmospheric discharges [2][3][4][5][6], and in systems for controlled thermonuclear fusion like Tokamak [19][20][21]. Providing a complete coverage of all in one review is impossible, and so we focus only on those data which allow the reader to understand the role of runaway electrons in gas discharges in an inhomogeneous electric field at a pressure of 0.01-1.2 MPa.…”

Chemical, Thermal, and Radiation Resistance of an Iron Porphyrin: A Model Study of Biosignature Stability

“…On planets, this type of radiation is produced during radioactive decay, as secondary radiation, and in terrestrial thunderstorms (Dwyer et al , 2008 ). Martian dust storms are also believed to produce gamma and X-rays (Arabshahi et al ., 2017 ).…”