Self-similar expansion of finite-size non-quasi-neutral plasmas into vacuum: Relation to the problem of ion acceleration
Self-similar expansion of finite-size non-quasi-neutral plasmas into vacuum: Relation to the problem of ion acceleration
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DOI：
10.1063/1.2162527
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发表时间：
2006-01-01
影响因子：
2.2
通讯作者：
Basko, MM
中科院分区：
文献类型：
--
作者：
Murakami, M;Basko, MM
提出了一种新的自相似解，它描述了有限等离子体质量向真空的非相对论膨胀，并充分考虑了电荷分离效应。仅当等离子体标尺长度 R 与德拜长度 lambda(D) 之比 Lambda=R/lambda(D) 不变时，即在 T-e(t) 与 [n(e)(t)](1-2/nu) 成比例的条件下，存在解，其中 nu=1、2 和 3 分别对应于平面、圆柱和球面几何形状。对于 Lambda >> 1，通过分析计算离子前沿的位置和加速离子的最大能量 E-i,E-max：特别是，对于 nu=3，可以发现 E-i,E-max=2ZT(e0)W(Lambda(2)/2)，其中 T-e0 是初始电子温度，Z 是离子电荷，W 是朗伯 W 函数。有人认为，当正确表述时，E-i,E-max 的结果可以比自相似解本身更广泛地应用。推广到双温电子系统揭示了加速离子的高能尾部仅由热电子群体决定的条件。 (c) 2006 年美国物理研究所。
A new self-similar solution is presented which describes nonrelativistic expansion of a finite plasma mass into vacuum with a full account of charge separation effects. The solution exists only when the ratio Lambda=R/lambda(D) of the plasma scale length R to the Debye length lambda(D) is invariant, i.e., under the condition T-e(t)proportional to[n(e)(t)](1-2/nu), where nu=1, 2, and 3 corresponds, respectively, to the planar, cylindrical, and spherical geometries. For Lambda >> 1 the position of the ion front and the maximum energy E-i,E-max of accelerated ions are calculated analytically: in particular, for nu=3 one finds E-i,E-max=2ZT(e0)W(Lambda(2)/2), where T-e0 is the initial electron temperature, Z is the ion charge, and W is the Lambert W function. It is argued that, when properly formulated, the results for E-i,E-max can be applied more generally than the self-similar solution itself. Generalization to a two-temperature electron system reveals the conditions under which the high-energy tail of accelerated ions is determined solely by the hot-electron population. (c) 2006 American Institute of Physics.