Three-dimensional reconstruction of CME-driven shock-streamer interaction from radio and EUV observations: a different take on the diagnostics of coronal magnetic fields

Abstract

On 2014 October 30, a band-splitted type II radio burst associated with a coronal mass ejection (CME) observed by the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamic Observatory (SDO) occurred over the southeast limb of the Sun. The fast expansion in all directions of the plasma front acted as a piston and drove a spherical fast shock ahead of it, whose outward progression was traced by simultaneous images obtained with the Nançay Radioheliograph (NRH). The geometry of the CME/shock event was recovered through 3D modeling, given the absence of concomitant stereoscopic observations, and assuming that the band-splitted type II burst was emitted at the intersection of the shock surface with two adjacent low-Alfven speed coronal streamers. From the derived spatiotemporal evolution of the standoff distance between shock and CME leading edge, we were finally able to infer the magnetic field strength $B$ in the inner corona. A simple radial profile of the form $B(r)=(12.6\pm 2.5)r^{-4}$ nicely fits our results, together with previous estimates, in the range $r=1.1-2.0$ solar radii.

Accepted for publication in Astronomy & Astrophysics Letters

References in corpus (1)

• Measuring coronal magnetic fields with remote sensing observations of shock waves

Cited by in corpus (4)

• The Solar Orbiter mission -- Science overview
• Evolution of the Alfvén Mach number associated with a coronal mass ejection shock
• First Observation of a Type II Solar Radio Burst Transitioning Between a Stationary and Drifting State
• Using radio triangulation to understand the origin of two subsequent type II radio bursts