Numerical Evaluations of Different Mechanisms to Produce Large-Scale Waves in the Solar Chromosphere

Abstract

In this work we examine the capability of two models to produce a Moreton wave, a type of large-scale wave which travels on the solar chromosphere at speeds of the order of fast magnetosonic waves. The first model consists in a blast-wave scenario associated with a flare event, which produces a very large release of energy in the form of a pressure pulse whose expansion causes a shock wave travelling in the solar corona. The second model consists in a flux rope rise produced by a coronal mass ejection (CME), whose movement generates a bow-shock ascending in the corona. The effect of the bowshock flanks on the chromosphere is believed by some authors to be responsible for the Moreton wave generation. The goal of this work is to analyze whether these models are capable of producing largescale waves phenomena in the solar atmosphere. For this purpose we implement numerical simulation of each model using adequate parameters to represent the solar environment. The results are numerically obtained by the use of the FLASH code, a powerful magnetohydrodynamics simulation tool capable of handling general compressible flow problems in many astrophysical environments, allowing for adaptive mesh refinement (AMR) and efficient parallel computing. The numerical results are compared with observations of an actual Moreton event in order to evaluate if the local density enhancements on the chromosphere produced by each model are large enough to be captured by solar telescopes.