Altitude distribution of electron concentration in ionospheric D-region in presence of time-varying solar radiation flux

TL;DR

This study investigates how solar flares affect electron concentration in the Earth's ionospheric D-region by analyzing VLF radio wave data and satellite observations, highlighting the roles of photo-ionization and recombination processes.

Contribution

It provides a detailed analysis of the altitude distribution of electron concentration changes during solar flare events, incorporating real-time VLF data and satellite measurements.

Findings

Electron concentration increases around 70 km altitude during solar flares.

Photo-ionization dominates electron gain during flare events.

Recombination processes counteract ionization at certain altitudes.

Abstract

In this paper, we study the influence of solar flares on electron concentration in the terrestrial ionospheric D-region by analyzing the amplitude and phase time variations of very low frequency (VLF) radio waves emitted by DHO transmitter (Germany) and recorded by the AWESOME receiver in Belgrade (Serbia) in real time. The rise of photo-ionization rate in the ionospheric D-region is a typical consequence of solar flare activity as recorded by GOES-15 satellite for the event on March 24, 2011 between 12:01 UT and 12:11 UT. At altitudes around 70 km, the photo-ionization and recombination are the dominant electron gain and electron loss processes, respectively. We analyze the relative contribution of each of these two processes in the resulting electron concentration variation in perturbed ionosphere.