Influence of hydrometeors on relativistic runaway electron avalanches

TL;DR

This study investigates how hydrometeors in thunderclouds influence the development of relativistic runaway electron avalanches, revealing that their presence can significantly alter avalanche growth lengths, which is crucial for accurate atmospheric modeling.

Contribution

The paper introduces the first detailed simulation of RREA considering hydrometeors, demonstrating that modeling approaches significantly affect avalanche growth predictions.

Findings

Hydrometeors can reduce avalanche length by up to 20%.

Modeling hydrometeors as separate objects yields different results than as a modified material.

Accounting for hydrometeors is essential for realistic atmospheric physics simulations.

Abstract

Previously, all studies in this area of atmospheric physics, namely, avalanches of relativistic runaway electrons (RREA), were carried out without taking into account the presence of hydrometeors in thunderclouds, which could seriously affect the results and their correspondence to actually observed natural phenomena. This article takes into account hydrometeors in clouds. In this work, the distribution of RREA was simulated in GEANT4 was simulated taking into account various concentrations of ice particles. Modeling showed that accounting for the presence of hydrometeors cannot be simplified and reduced to a change in the main substance. Two methods are considered - modeling of volumetric hydrometeors as separate modeling objects and as a simple change in the components of a whole substance (adding water to air with a corresponding density). These methods show completely different results. Modeling by volumes of hydrometeors shows a decrease in the length of the avalanche by 20 %, on the other hand, when modeling with a modified material, the length changed only by 1 %. This suddenly proves that hydrometeors should be taken into account in research, as they can significantly change the growth length of an avalanche in real thunderstorm condition.