Electric fields in solar magnetic structures due to gradient driven instabilities: heating and acceleration of particles
Electric fields in solar magnetic structures due to gradient driven instabilities: heating and acceleration of particles
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由于梯度驱动的不稳定性而导致的太阳磁结构中的电场：粒子的加热和加速
DOI：
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发表时间：
2009
期刊：
影响因子：
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通讯作者：
S. Poedts
中科院分区：
文献类型：
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作者：
J. Vranjes;S. Poedts
讨论了由密度梯度、温度梯度和磁场梯度驱动的静电不稳定性在太阳磁结构中的应用。强增长模式被发现的一些典型的等离子体参数。这些不稳定性（i）意味着电场的存在，可以在相对于磁场矢量的垂直和平行方向上加速等离子体粒子，以及（ii）可以随机加热离子。垂直加速度是由E × B漂移对离子和电子的同等作用决定的，而平行加速度对电子最有效。实验证实的随机加热示出主要在垂直于磁场矢量的方向上起作用，并且对较重的离子起作用更强。能量释放率和加热可能超过几个数量级的值，被认为是太阳日冕中自我持续加热所必需的。用于加速和加热的能量源存储在所述背景梯度中。
The electrostatic instabilities driven by the gradients of the density, temperature and magnetic field are discussed in their application to solar magnetic structures. Strongly growing modes are found for some typical plasma parameters. These instabilities (i) imply the presence of electric fields that can accelerate the plasma particles in both perpendicular and parallel directions with respect to the magnetic field vector, and (ii) can stochastically heat ions. The perpendicular acceleration is to the leading order determined by the E × B drift acting equally on both ions and electrons, while the parallel acceleration is most effective on electrons. The experimentally confirmed stochastic heating is shown to act mainly in the direction perpendicular to the magnetic field vector and acts stronger on heavier ions. The energy release rate and heating may exceed for several orders of magnitude the value accepted as necessary for a self-sustained heating in the solar corona. The energy source for both the acceleration and the heating is stored in the mentioned background gradients.