Atmospheric ionization induced by precipitating electrons: Comparison of CRAC:EPII model with parametrization model

TL;DR

This paper introduces the CRAC:EPII model, a Monte Carlo simulation tool for atmospheric ionization caused by precipitating electrons, and compares its results with an analytical parametrization, validating its accuracy with observational data.

Contribution

The paper presents a new Monte Carlo based model, CRAC:EPII, for simulating atmospheric ionization from precipitating electrons, incorporating detailed physical processes and validated against existing parametrization and measurements.

Findings

CRAC:EPII shows good agreement with analytical parametrization.

The model accurately estimates ion production rates using balloon data.

Physical processes like Bremsstrahlung and positron annihilation are explicitly included.

Abstract

A new model CRAC:EPII (Cosmic Ray Atmospheric Cascade: Electron Precipitation Induced Ionization) is presented. The CRAC:EPII is based on Monte Carlo simulation of precipitating electrons propagation and interaction with matter in the Earth atmosphere. It explicitly considers energy deposit: ionization, pair production, Compton scattering, generation of Bremsstrahlung high energy photons, photo-ionization and annihilation of positrons, multiple scattering as physical processes accordingly. The propagation of precipitating electrons and their interactions with atmospheric molecules is carried out with the GEANT4 simulation tool PLANETOCOSMICS code using NRLMSISE 00 atmospheric model. The ionization yields is compared with an analytical parametrization for various energies of incident precipitating electron, using a flux of mono-energetic particles. A good agreement between the two models is achieved. Subsequently, on the basis of balloon-born measured spectra of precipitating electrons at 30.10.2002 and 07.01.2004, the ion production rate in the middle and upper atmosphere is estimated using the CRAC:EPII model