Three-dimensional numerical simulations of impulsively generated MHD waves in solar coronal loops

¹ Institute of Physics, UMCS, ul. Radziszewskiego 10, 20-031 Lublin, Poland e-mail: mselwa@kft.umcs.lublin.pl
² Astronomical Observatory, Jagiellonian University, ul. Orla 171, 30-244 Kraków, Poland

Received: 21 January 2004
Accepted: 26 March 2004

Abstract

Impulsively generated magnetohydrodynamic waves in a typical EUV solar coronal loop are studied numerically using a three-dimensional FLASH code. Our results reveal several 3D effects such as distinctive time signatures which are collected at a detection point inside the loop. A slow magnetosonic wave generates a significant variation in the mass density profile with a time scale of the order of 40 s. A fast kink wave affects the mass density, too, but its magnitude is much lower than in the case of a slow wave. Time scales which are associated with the fast kink wave are generally shorter than in the case of a slow wave; the former are in the range of a dozen or so seconds. Temporal signatures of a fast sausage wave reveal ∼5-s oscillations in the quasi-periodic phase. Impulses which are launched outside the loop excite several-second oscillations in the mass density. Time signatures depend on the position of the detection point; they are usually more complex further away from the exciter.