On production of gamma rays and Relativistic Runaway Electron Avalanches from Martian dust storms

TL;DR

This study uses Monte Carlo simulations to demonstrate that Martian dust storms can generate relativistic electron avalanches and gamma rays, similar to Earth's terrestrial gamma ray flashes, which could be observed by instruments on Mars.

Contribution

First theoretical prediction of gamma ray production and electron avalanches in Martian dust storms using simulations and electric field estimates.

Findings

Martian dust storms can produce energetic electron avalanches.

Gamma ray fluxes on Mars could be comparable to terrestrial gamma ray flashes.

Potential for observation by ground-based or satellite instruments.

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.