Coronal Shock Waves, EUV waves, and their Relation to CMEs. II. Modeling MHD Shock Wave Propagation Along the Solar Surface, Using Nonlinear Geometrical Acoustics

TL;DR

This paper models the propagation of coronal shock waves and EUV waves along the solar surface using nonlinear geometrical acoustics, revealing deceleration and lengthening effects not seen in linear models.

Contribution

It introduces a nonlinear geometrical acoustics method based on WKB to simulate shock wave propagation on the solar surface, accounting for nonlinear effects.

Findings

Shock waves decelerate and lengthen during propagation.

Linear approximation predicts constant length and slight acceleration.

Model captures nonlinear wave behaviors observed in the solar corona.

Abstract

We model the propagation of a coronal shock wave, using nonlinear geometrical acoustics. The method is based on the Wentzel-Kramers-Brillouin (WKB) approach and takes into account the main properties of nonlinear waves: i) dependence of the wave front velocity on the wave amplitude, ii) nonlinear dissipation of the wave energy, and iii) progressive increase in the duration of solitary shock waves. We address the method in detail and present results of the modeling of the propagation of shock-associated extreme-ultraviolet (EUV) waves as well as Moreton waves along the solar surface in the simplest solar corona model. The calculations reveal deceleration and lengthening of the waves. In contrast, waves considered in the linear approximation keep their length unchanged and slightly accelerate.