The Wave-Driver System of the Off-Disk Coronal Wave 17 January 2010

TL;DR

This study combines EUV observations and an analytic model to analyze the 2010 solar event, revealing a wave-driver system with a weak shock driven by CME expansion, providing insights into coronal wave dynamics.

Contribution

It introduces a combined observational and modeling approach to characterize the wave-driver system in a specific solar event, highlighting the wave's evolution and shock properties.

Findings

The wave signature is dome-shaped with on-disk and off-disk components.

The off-disk wave involves intensity enhancements linked to CME expansion.

The shock standoff distance increases rapidly near the Sun, indicating lateral CME expansion.

Abstract

We study the 17 January 2010 flare-CME-wave event by using STEREO/SECCHI EUVI and COR1 data. The observational study is combined with an analytic model which simulates the evolution of the coronal-wave phenomenon associated with the event. From EUV observations, the wave signature appears to be dome shaped having a component propagating on the solar surface (v~280 km s-1) as well as off-disk (v~600 km s-1) away from the Sun. The off-disk dome of the wave consists of two enhancements in intensity, which conjointly develop and can be followed up to white-light coronagraph images. Applying an analytic model, we derive that these intensity variations belong to a wave-driver system with a weakly shocked wave, initially driven by expanding loops, which are indicative of the early evolution phase of the accompanying CME. We obtain the shock standoff distance between wave and driver from observations as well as from model results. The shock standoff distance close to the Sun (<0.3 Rs above the solar surface) is found to rapidly increase with values of ~0.03-0.09 Rs which give evidence of an initial lateral (over-)expansion of the CME. The kinematical evolution of the on-disk wave could be modeled using input parameters which require a more impulsive driver (t=90 s, a=1.7 km s-2) compared to the off-disk component (t=340 s, a=1.5 km s-2).