Modelling the Propagation of a Weak Fast-Mode MHD Shock Wave near a 2D Magnetic Null Point Using Nonlinear Geometrical Acoustics

被引：15

作者：

Afanasyev, A. N. ^{[1
]}

Uralov, A. M. ^{[1
]}

机构：

[1] Inst Solar Terr Phys SB RAS, Irkutsk 664033, Russia

来源：

SOLAR PHYSICS | 2012年 / 280卷 / 02期

关键词：

Magnetohydrodynamics; Waves; propagation; shock; Heating; coronal; MAGNETOHYDRODYNAMIC OSCILLATIONS; NEIGHBORHOOD; SOLAR; RECONNECTION;

D O I：

10.1007/s11207-012-0022-9

中图分类号：

P1 [天文学];

学科分类号：

0704 ;

摘要：

We present the results of analytical modelling of fast-mode magnetohydrodynamic wave propagation near a 2D magnetic null point. We consider both a linear wave and a weak shock and analyse their behaviour in cold and warm plasmas. We apply the nonlinear geometrical acoustics method based on the Wentzel-Kramers-Brillouin approximation. We calculate the wave amplitude, using the ray approximation and the laws of solitary shock wave damping. We find that a complex caustic is formed around the null point. Plasma heating is distributed in space and occurs at a caustic as well as near the null point due to substantial nonlinear damping of the shock wave. The shock wave passes through the null point even in a cold plasma. The complex shape of the wave front can be explained by the caustic pattern.

引用

页码：561 / 574

页数：14

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