Competition between shock and turbulent heating in coronal loop system
Competition between shock and turbulent heating in coronal loop system
复制标题
日冕环路系统中激波与湍流加热的竞争
DOI：
10.1093/mnras/stw2032
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发表时间：
2016
影响因子：
4.8
通讯作者：
Takuma Matsumoto
中科院分区：
文献类型：
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作者：
Matsumoto Takuma;Takuma Matsumoto
为了区分日冕加热问题的竞争模型，在高空间分辨率下进行了2.5维磁流体动力学（MHD）模拟。一个由在光球中激发的阿尔夫萨芬波驱动的单一日冕环是本研究的目标。在我们的模拟中，日冕结构作为阿尔夫萨曼波传输和耗散的自然结果再现。此外，当空间分辨率从25 km变化到3 km时，日冕结构保持不变，尽管环顶温度随着空间分辨率的增加而增加。在4 Mm高度处，加热机制在整个磁冠层上逐渐变化，在磁冠层以下，激波和MHD湍流是主要的加热过程。在磁冠层上方，激波加热速率降低到总加热速率的10%以下，而MHD湍流提供了显著的能量来平衡辐射冷却和热传导的损失或增益。本研究显示的可压缩性的重要性将对太阳色球层MHD湍流理论的成功前景产生重大影响。
2.5-dimensional magnetohydrodynamic (MHD) simulations are performed with high spatial resolution in order to distinguish between competing models of the coronal heating problem. A single coronal loop powered by Alfvén waves excited in the photosphere is the target of this study. The coronal structure is reproduced in our simulations as a natural consequence of the transportation and dissipation of Alfvén waves. Further, the coronal structure is maintained as the spatial resolution is changed from 25 to 3 km, although the temperature at the loop top increases with the spatial resolution. The heating mechanisms change gradually across the magnetic canopy at a height of 4 Mm. Below the magnetic canopy, both the shock and the MHD turbulence are dominant heating processes. Above the magnetic canopy, the shock heating rate reduces to less than 10 per cent of the total heating rate while the MHD turbulence provides significant energy to balance the radiative cooling and thermal conduction loss or gain. The importance of compressibility shown in this study would significantly impact on the prospects of successful MHD turbulence theory in the solar chromosphere.