Assessing the spectral characteristics of band splitting type II radio bursts observed by CALLISTO spectrometers

TL;DR

This study analyzes the spectral properties of band-splitting type II radio bursts observed by CALLISTO, revealing their correlation with solar cycle dynamics, CME speeds, and plasma conditions, thereby enhancing space weather prediction capabilities.

Contribution

It provides a comprehensive analysis of the spectral characteristics of band-splitting type II radio bursts and their association with solar cycle parameters and CME properties.

Findings

Type II burst frequency shows bimodal distribution with peaks in 2012 and 2015.

Strong correlation (R=0.87) between CME shock speeds from spectra and SOHO-LASCO data.

60% of bursts originate from western longitudes, indicating spatial distribution patterns.

Abstract

Metric type II radio bursts are usually early indicators of CME-driven shocks and other space weather phenomena in the solar corona. This paper presents a detailed investigation of the spectral properties of band-splitting type II radio bursts and their association with sunspot number. Using type II radio bursts in a frequency range 20 to 200MHz observed by CALLISTO from 2010 to 2017, it was discovered that the analyzed type II shock height, magnetic field strength, CME shock speed, and Alfven speed synchronize with the trajectory of the solar cycle 24. Also, the study revealed that the onset of the declining phase of solar cycle 24 has the highest electron density. The analysis ascertained that the frequency of type II bursts depicts a bimodal distribution during the study period, with peaks in 2012 and 2015. Further, a good correlation(with correlation factor R=0.87) was obtained between the estimated CME shock speeds from the dynamic spectra, and the associated CME speeds from SOHO-LASCO. Moreover, the study confirmed a significant correlation(R=0.8) between the absolute drift rates and the plasma frequency. Additionally, the study explored that 60% of the type II radio bursts considered in this study emanated from the western longitudes. Hence, these findings emphasize that the temporal dynamics of the physical conditions of band-splitting type II radio are essential parameters in space weather monitoring and forecasting.