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

Abstract

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 II burst. No models were assumed for the coronal electron density (N(r)) we used in the estimation. The results obtained with these two independent methods correspond to different heliocentric distances (r) in the range ≈ 2.5 – 4.5 R , but they show excellent consistency and could be fit with a single power-law distribution of the type B(r) = 5.7r−2.6 G, which is applicable in that distance range. The power-law index (i.e. −2.6) is in good agreement with the results obtained in previous studies by different methods.