The Effect of Uniform and Non-uniform Electron Density Models for Determining Shock Speed of a Type II Solar Radio Burst

TL;DR

This study compares uniform and non-uniform electron density models to estimate shock speeds of type II solar radio bursts, finding the non-uniform model yields more realistic lower shock speed estimates in active solar regions.

Contribution

It introduces the use of non-uniform electron density models for more accurate shock speed estimation of type II solar radio bursts.

Findings

Uniform model estimates shock speed at 2131 km/s.

Non-uniform model estimates shock speed at 766 km/s.

Non-uniform model is more appropriate for active solar regions.

Abstract

Solar flare is one of the most important solar activities which emit all electromagnetic waves in gigantic burst. The radio emission can be used to determine the physical properties of the solar flares. The e-CALLISTO worldwide network is designed to detect the radio emission of the solar flares and this study used the spectroscopic data from the e-CALLISTO system. Among the five types of solar radio bursts, this study was focused on type II radio bursts. The spectroscopic analysis estimated the shock speed of type II radio bursts using the uniform electron density model and the nonuniform electron density model of the sun. The shock speed is proportional to the electron density (Ne) and inversely proportional to the rate of change in electron density with altitude (dNe/dr). The determined shock speed at the altitude of one solar radius is 2131 km/s for uniform model and 766 km/s for non-uniform model. Although the uniform electron density model is widely used we attempted the non-uniform electron density since in the active region of the sun, the electron densities are non-uniform. The estimated shock speeds of uniform density model is relatively high so that it is reasonable to use non-uniform electron density model for shock speed estimation of type II radio bursts.