Inhibition of electron thermal conduction by electromagnetic instabilities. [in stellar coronas
Inhibition of electron thermal conduction by electromagnetic instabilities. [in stellar coronas
复制标题
电磁不稳定性对电子热传导的抑制。
DOI：
10.1086/171072
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发表时间：
1992
期刊：
影响因子：
--
通讯作者：
D. Eichler
中科院分区：
文献类型：
--
作者：
A. Levinson;D. Eichler
研究了热磁化等离子体中电磁不稳定性对热流的抑制作用。由于电子分布函数的各向异性，低频电磁波变得不稳定。由此产生的混沌磁场以特定的有效平均自由程散射电子。考虑了由波波相互作用、非线性散射、波传播和碰撞阻尼引起的不稳定性饱和。利用一个简单的模型来估计饱和水平和散射，发现有效平均自由程是自一致的，并且随着温度梯度的长度而减小。结果，仅限于模型的假设，应用于天体物理系统。对于一些星际云来说，不稳定性是很重要的。碰撞阻尼稳定等离子体，热传导可以由超热电子控制。
Heat flux inhibition by electromagnetic instabilities in a hot magnetized plasma is investigated. Low-frequency electromagnetic waves become unstable due to anisotropy of the electron distribution function. The chaotic magnetic field thus generated scatters the electrons with a specific effective mean free path. Saturation of the instability due to wave-wave interaction, nonlinear scattering, wave propagation, and collisional damping is considered. The effective mean free path is found self-consistently, using a simple model to estimate saturation level and scattering, and is shown to decrease with the temperature gradient length. The results, limited to the assumptions of the model, are applied to astrophysical systems. For some interstellar clouds the instability is found to be important. Collisional damping stabilizes the plasma, and the heat conduction can be dominated by superthermal electrons.