The Broken Lane of a Type II Radio Burst Caused by Collision of a Coronal Shock with a Flare Current Sheet

TL;DR

This study analyzes a peculiar solar radio burst with a broken lane caused by a coronal shock colliding with a current sheet, combining multi-wavelength data to understand the event and estimate the current sheet's thickness.

Contribution

It provides a detailed multi-wavelength analysis of a broken lane type II radio burst and estimates the current sheet thickness from radio data, linking shock dynamics with solar structures.

Findings

The broken lane was caused by the shock-current sheet collision.

The current sheet thickness estimate aligns with previous measurements.

The shock passed through the current sheet, restoring the radio burst lane.

Abstract

We investigated a peculiar metric type II solar radio burst with a broken lane structure, which was observed on November 13, 2012. In addition to the radio data, we also studied the data in the other wavelengths. The bursts were associated with two CMEs and two flares that originated from active region AR 11613. A long current sheet was developed in the first CME, and the second CME collided with the current sheet first and then merged with the first one. Combing information revealed by the multi-wavelength data indicated that a coronal shock accounting for the type II radio burst, and that the collision of this shock with the current sheet resulted in the broken lane of the type II radio burst. The type II burst lane resumed after the shock passed through the current sheet. We further estimated the thickness of the current sheet according to the gap on the lane of the type II burst, and found that the result is consistent with previous ones obtained for various events observed in different wavelengths by different instruments. In addition, the regular type II burst associated with the first CME/flare was also studied, and the magnetic field in each source region of the two type II bursts was further deduced in different way.