Strength of the Solar Coronal Magnetic field - A Comparison of Independent Estimates Using Contemporaneous Radio and White-light Observations

TL;DR

This study compares two independent methods to estimate the coronal magnetic field during a CME event, finding consistent results that follow a power-law distribution, enhancing understanding of solar magnetic structures.

Contribution

It introduces a model-independent approach to estimate the coronal magnetic field using white-light and radio observations, confirming a power-law distribution with previous findings.

Findings

Both methods yield consistent magnetic field estimates.

The magnetic field follows a power-law distribution with index -2.6.

Results align with previous studies using different techniques.

Abstract

We estimated the coronal magnetic field strength ($B$) during the 23 July 2016 coronal mass ejection (CME) event using i) the flux rope structure of the CME in the whitelight coronagraph images and ii) the band splitting in the associated type {\sc II} burst. No models were assumed for the coronal electron density ($N(r)$) used in the estimation.The results obtained using the above two independent methods correspond to different heliocentric distances ($r$) in the range $\approx$\,2.5\,--\,4.5$\rm R_{\odot}$, but they show excellent consistency and could be fitted with a single power-law distribution of the type $B(r)=5.7r^{-2.6}$ \textrm{G}, which is applicable in the aforementioned distance range. The power law index i.e. $-2.6$) is in good agreement with the results obtained in previous studies by different methods.