Statistical Survey of Type III Radio Bursts at Long Wavelengths Observed by the Solar TErrestrial RElations Observatory (STEREO)/Waves Instruments: Radio Flux Density Variations with Frequency

TL;DR

This study analyzes 152 Type III radio bursts observed by STEREO/Waves, examining flux density variations across frequencies and proposing a simplified model to explain propagation effects.

Contribution

It provides a comprehensive statistical analysis of Type III radio bursts at long wavelengths and introduces a simplified analytical model of flux density as a function of radial distance.

Findings

Maximum flux density occurs at 1 MHz on both spacecraft.

High- and low-frequency cutoffs observed in 60% of events, indicating propagation effects.

The analytical model aligns with observed flux density variations.

Abstract

We have performed a statistical study of $152$ Type III radio bursts observed by Solar TErrestrial RElations Observatory (STEREO)/Waves between May 2007 and February 2013. We have investigated the flux density between $125$kHz and $16$MHz. Both high- and low-frequency cutoffs have been observed in $60\,%$ of events suggesting an important role of propagation. As already reported by previous authors, we observed that the maximum flux density occurs at $1$MHz on both spacecraft. We have developed a simplified analytical model of the flux density as a function of radial distance and compared it to the STEREO/Waves data.