OBSERVATIONAL SIGNATURES OF THE CORONAL KINK INSTABILITY WITH THERMAL CONDUCTION
OBSERVATIONAL SIGNATURES OF THE CORONAL KINK INSTABILITY WITH THERMAL CONDUCTION
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DOI：
10.1088/0004-637x/745/1/53
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发表时间：
2012-01-20
影响因子：
4.9
通讯作者：
Srivastava, Abhishek K.
中科院分区：
文献类型：
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作者：
Botha, G. J. J.;Arber, T. D.;Srivastava, Abhishek K.
数值模拟结果表明，沿沿着磁力线的热传导对日冕环扭结不稳定性的演化起着重要的作用。这项研究提出了观测签名的扭结不稳定性在长日冕环路时，平行的热传导。通过数值求解三维非线性磁流体动力学方程组，模拟了初始处于不稳定平衡状态的日冕环的演化过程。该环的长度为80 μ m，宽度为8 μ m，初始最大扭曲为Φ = 11.5 π，其中F是半径的函数。初始环参数是从过渡区和日冕探测器（TRACE）171埃波段观察到的高度扭曲环中获得的。从数据中生成合成观测值。这些观测量包括空间和时间平均值，以说明TRACE图像的分辨率和曝光时间。平行热传导将最大局部温度降低多达一个数量级。这意味着形成不同的光谱线，并且在包括或不包括热传导的情况下，不同的内部回路结构是可见的。然而，响应函数对宽范围的温度进行采样。结果是，包含平行热导率对观测特征的影响并不像最高温度的数量级降低所暗示的那样大;净效应是模糊了环结构的内部特征。
It is known from numerical simulations that thermal conduction along magnetic field lines plays an important role in the evolution of the kink instability in coronal loops. This study presents the observational signatures of the kink instability in long coronal loops when parallel thermal conduction is included. The three-dimensional nonlinear magnetohydrodynamic equations are solved numerically to simulate the evolution of a coronal loop that is initially in an unstable equilibrium. The loop has length 80 Mm, width 8 Mm, and an initial maximum twist of Phi = 11.5 pi, where F is a function of the radius. The initial loop parameters are obtained from a highly twisted loop observed in the Transition Region and Coronal Explorer (TRACE) 171 angstrom wave band. Synthetic observables are generated from the data. These observables include spatial and temporal averaging to account for the resolution and exposure times of TRACE images. Parallel thermal conduction reduces the maximum local temperature by up to an order of magnitude. This means that different spectral lines are formed and different internal loop structures are visible with or without the inclusion of thermal conduction. However, the response functions sample a broad range of temperatures. The result is that the inclusion of parallel thermal conductivity does not have as large an impact on observational signatures as the order of magnitude reduction in the maximum temperature would suggest; the net effect is a blurring of internal features of the loop structure.