LINEAR VLASOV THEORY IN THE SHEARING SHEET APPROXIMATION WITH APPLICATION TO THE MAGNETO-ROTATIONAL INSTABILITY
LINEAR VLASOV THEORY IN THE SHEARING SHEET APPROXIMATION WITH APPLICATION TO THE MAGNETO-ROTATIONAL INSTABILITY
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DOI：
10.1088/0004-637x/792/1/70
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发表时间：
2014-09-01
影响因子：
4.9
通讯作者：
Quataert, Eliot
中科院分区：
文献类型：
--
作者：
Heinemann, Tobias;Quataert, Eliot
我们在剪切片近似中导出了热的、无碰撞的、电荷中性的等离子体轴对称扰动的电导率张量。我们的结果将众所周知的均匀等离子体线性弗拉索夫理论推广到差分旋转等离子体，并可用于广泛的动力学稳定性计算。我们将这些结果应用于无碰撞等离子体磁旋转不稳定性（MRI）的线性理论。我们用解析和数值方法展示了本文推导出的一般动态论结果如何在适当的范围内减少先前文献中的结果，包括低频导向中心（或“动力学MHD”）近似、霍尔磁流体动力学（MHD）和陀螺粘性近似。我们重新审视了核磁共振成像的冷等离子体模型，并表明，与先前的结果相反，在冷等离子体近似中，初始未磁化的无碰撞等离子体对轴对称扰动是线性稳定的。除了应用于天体物理等离子体之外，我们的结果还为在实验室实验中评估差分旋转等离子体的线性稳定性提供了一个有用的框架。
We derive the conductivity tensor for axisymmetric perturbations of a hot, collisionless, and charge-neutral plasma in the shearing sheet approximation. Our results generalize the well-known linear Vlasov theory for uniform plasmas to differentially rotating plasmas and can be used for wide range of kinetic stability calculations. We apply these results to the linear theory of the magneto-rotational instability (MRI) in collisionless plasmas. We show analytically and numerically how the general kinetic theory results derived here reduce in appropriate limits to previous results in the literature, including the low-frequency guiding center (or "kinetic MHD") approximation, Hall magnetohydrodynamics (MHD), and the gyro-viscous approximation. We revisit the cold plasma model of the MRI and show that, contrary to previous results, an initially unmagnetized collisionless plasma is linearly stable to axisymmetric perturbations in the cold plasma approximation. In addition to their application to astrophysical plasmas, our results provide a useful framework for assessing the linear stability of differentially rotating plasmas in laboratory experiments.