On heat conduction in an irregular magnetic field. Part 1
On heat conduction in an irregular magnetic field. Part 1
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关于不规则磁场中的热传导。
DOI：
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发表时间：
2022
影响因子：
2.5
通讯作者：
E. Paul
中科院分区：
文献类型：
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作者：
P. Helander;S. Hudson;E. Paul
本文讨论了嵌入在不规则磁场中的等离子体中的各向异性热传导问题。如果碰撞平均自由程超过电子回旋半径，则热传导率沿场线的沿着比穿过场线的大得多，这增强了穿过不存在良好通量表面的区域的传输。认识到，各向异性热传导可能会被铸造在一个变分的形式，并通过构建越来越复杂的审判功能，是基于不变的和几乎不变的结构下的磁场线流，边界上推导出这种增强和温度变化沿着磁场。通过这种方式，即使在温度的解受磁场线的分形结构支配时的小的非线性扩散极限中，也可以在不求解扩散方程的情况下快速构造温度的非常精确的近似。
Anisotropic heat conduction in a plasma embedded in a magnetic field with irregular, possibly chaotic, field lines is discussed. If the collisional mean free path exceeds the electron gyroradius, the heat conductivity is much larger along the field lines than across them, and this enhances the transport across a domain where good flux surfaces do not exist. Recognising that anisotropic heat conduction may be cast in a variational form, and by constructing increasingly sophisticated trial functions that are based on invariant and almost-invariant structures under the magnetic field-line flow, bounds are derived on this enhancement and on the temperature variation along the magnetic field. In this way, remarkably accurate approximations for the temperature can be rapidly constructed without solving the diffusion equation, even in the small perpendicular-diffusion limit when the solution for the temperature is dominated by the fractal structure the magnetic field lines.