Validity of quasilinear theory: refutations and new numerical confirmation
Validity of quasilinear theory: refutations and new numerical confirmation
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DOI：
10.1088/0741-3335/53/2/025012
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发表时间：
2011-02
影响因子：
2.2
通讯作者：
N. Besse;Y. Elskens;D. Escande;P. Bertrand
中科院分区：
文献类型：
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作者：
N. Besse;Y. Elskens;D. Escande;P. Bertrand
近几十年来，描述弱温束-等离子体不稳定性的准线性（QL）理论的有效性一直是一个有争议的话题。这个问题是重新解决，无论是分析和数值模拟，受益于现代计算机的力量，并在过去十年的发展，弗拉索夫代码赋予的准确性和弱数值扩散。自洽的数值模拟内的Vlasov波的描述表明，QL理论仍然有效的强混沌扩散制度。然而，有一个非QL政权之前饱和，这证实了以前的分析工作和数值模拟，但矛盾的另一个分析工作。我们分析了模式耦合的情况下，在饱和制度的不稳定性，高原是存在于尾部的粒子分布函数。这使一些试图证明或反驳QL理论在弱温束-等离子体不稳定性的强非线性区域中的有效性的分析工作失效。
The validity of quasilinear (QL) theory describing the weak warm beam–plasma instability has been a controversial topic for several decades. This issue is tackled anew, both analytically and by numerical simulations which benefit from the power of modern computers and from the development in the last decade of Vlasov codes endowed with both accuracy and weak numerical diffusion. Self-consistent numerical simulations within the Vlasov-wave description show that QL theory remains valid in the strong chaotic diffusion regime. However, there is a non-QL regime before saturation, which confirms previous analytical work and numerical simulation, but contradicts another analytical work. We show analytically the absence of mode coupling in the saturation regime of the instability where a plateau is present in the tail of the particle distribution function. This invalidates several analytical works trying to prove or to contradict the validity of QL theory in the strongly nonlinear regime of the weak warm beam–plasma instability.