THE INSTABILITY AND NON-EXISTENCE OF MULTI-STRANDED LOOPS WHEN DRIVEN BY TRANSVERSE WAVES

被引:31
|
作者
Magyar, N. [1 ]
Van Doorsselaere, T. [1 ]
机构
[1] Katholieke Univ Leuven, Ctr Math Plasma Astrophys CmPA, 200B Bus 2400, B-3001 Louvain, Belgium
来源
ASTROPHYSICAL JOURNAL | 2016年 / 823卷 / 02期
关键词
magnetohydrodynamics (MHD); Sun: corona; waves; KELVIN-HELMHOLTZ INSTABILITY; SOLAR CORONAL LOOPS; RESONANTLY DAMPED OSCILLATIONS; EMISSION-MEASURE PROFILES; STAGGERED MESH SCHEME; MAGNETIC-FLUX TUBES; KINK OSCILLATIONS; ACTIVE-REGION; ALFVEN WAVES; THERMAL STRUCTURE;
D O I
10.3847/0004-637X/823/2/82
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
In recent years, omni-present transverse waves have been observed in all layers of the solar atmosphere. Coronal loops are often modeled as a collection of individual strands in order to explain their thermal behavior and appearance. We perform three-dimensional (3D) ideal magnetohydrodynamics simulations to study the effect of a continuous small amplitude transverse footpoint driving on the internal structure of a coronal loop composed of strands. The output is also converted into synthetic images, corresponding to the AIA 171 and 193 angstrom passbands, using FoMo. We show that the multi-stranded loop ceases to exist in the traditional sense of the word, because the plasma is efficiently mixed perpendicularly to the magnetic field, with the Kelvin-Helmholtz instability acting as the main mechanism. The final product of our simulation is a mixed loop with density structures on a large range of scales, resembling a power-law. Thus, multi-stranded loops are unstable to driving by transverse waves, and this raises strong doubts on the usability and applicability of coronal loop models consisting of independent strands.
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页数:8
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