The energy partitioning of non-thermal particles in a plasma: the Coulomb logarithm revisited
The energy partitioning of non-thermal particles in a plasma: the Coulomb logarithm revisited
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DOI：
10.1088/0741-3335/50/12/124016
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发表时间：
2008-05
影响因子：
2.2
通讯作者：
R. Singleton;L. Brown
中科院分区：
文献类型：
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作者：
R. Singleton;L. Brown
Brown、Preston 和 Singleton (BPS) 已精确计算出高度电离和弱耦合至中度耦合等离子体中的带电粒子阻止本领，其等离子体密度处于领先和次领先的精度。由于 BPS 的计算技术可能对某些人来说不熟悉，并且由于相同的方法也可以用于其他能量传输现象，因此我们将回顾计算背后的主要思想。 BPS 使用他们的阻止本领计算来推导福克-普朗克方程，该方程也精确到前导和次前导阶，我们也将对此进行回顾。我们使用福克-普朗克方程来计算穿过等离子体的带电粒子的电子-离子能量分配。该应用的动机是惯性约束聚变的点火——传递给离子的能量越多意味着点火的机会越大，反之亦然。因此，尽可能准确地计算电子和离子的能量损失部分非常重要。计算穿过等离子体的带电粒子的电子-离子能量分裂的一种方法涉及对阻止本领 dE/dx 进行积分。然而，当带电粒子减速并热化到背景等离子体中时，这种计算电子-离子能量分裂的方法就失效了。因此，它会遭受可能与 T/E0 一样大的系统误差，其中 T 是等离子体温度，E0 是带电粒子的初始能量。这里提出的形式是为了解释热化过程而设计的，它提供了近乎精确的结果。
The charged particle stopping power in a highly ionized and weakly to moderately coupled plasma has been calculated exactly to leading and next-to-leading accuracy in the plasma density by Brown, Preston and Singleton (BPS). Since the calculational techniques of BPS might be unfamiliar to some, and since the same methodology can also be used for other energy transport phenomena, we will review the main ideas behind the calculation. BPS used their stopping power calculation to derive a Fokker–Planck equation, also accurate to leading and next-to-leading orders, and we will also review this. We use this Fokker–Planck equation to compute the electron–ion energy partitioning of a charged particle traversing a plasma. The motivation for this application is ignition for inertial confinement fusion—more energy delivered to the ions means a better chance of ignition, and conversely. It is therefore important to calculate the fractional energy loss to electrons and ions as accurately as possible. One method by which one calculates the electron–ion energy splitting of a charged particle traversing a plasma involves integrating the stopping power dE/dx. However, as the charged particle slows down and becomes thermalized into the background plasma, this method of calculating the electron–ion energy splitting breaks down. As a result, it suffers a systematic error that may be as large as T/E0, where T is the plasma temperature and E0 is the initial energy of the charged particle. The formalism presented here is designed to account for the thermalization process and it provides results that are near-exact.