Case Study of Four Homologous Large-Scale Coronal Waves Observed on 2010 April 28 and 29

TL;DR

This study analyzes four homologous large-scale coronal waves observed over two days, revealing their consistent propagation characteristics, correlation with magnetic energy buildup, and supporting their classification as nonlinear fast-mode magnetosonic waves.

Contribution

It provides detailed observational evidence linking wave velocities, Mach numbers, and magnetic energy buildup, supporting the nonlinear fast-mode magnetosonic wave interpretation.

Findings

All waves propagated at constant velocities between 220-340 km/s.

The strongest wave had a velocity of 337 km/s and a Mach number of ~1.09.

Magnetosonic Mach numbers and velocities are correlated.

Abstract

On 2010 April 28 and 29, the Solar TErrestrial Relations Observatory B/Extreme Ultraviolet Imager observed four homologous large-scale coronal waves, the so-called EIT-waves, within 8 hr. All waves emerged from the same source active region, were accompanied by weak flares and faint coronal mass ejections, and propagated into the same direction at constant velocities in the range of ~220-340 km s-1. The last of these four coronal wave events was the strongest and fastest, with a velocity of 337 +/- 31 km s-1 and a peak perturbation amplitude of ~1.24, corresponding to a magnetosonic Mach number of Mms ~ 1.09. The magnetosonic Mach numbers and velocities of the four waves are distinctly correlated, suggestive of the nonlinear fast-mode magnetosonic wave nature of the events. We also found a correlation between the magnetic energy buildup times and the velocity and magnetosonic Mach number.