Department of Aerospace Engineering, Texas A&M University, College Station, Texas 77843, USA.
Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA.
Phys Rev E. 2017 May;95(5-1):053212. doi: 10.1103/PhysRevE.95.053212. Epub 2017 May 25.
The energy of plasma waves can be moved up and down the spectrum using chirped modulations of plasma parameters, which can be driven by external fields. Depending on whether the wave spectrum is discrete (bounded plasma) or continuous (boundless plasma), this phenomenon is called ladder climbing (LC) or autoresonant acceleration of plasmons. It was first proposed by Barth et al. [Phys. Rev. Lett. 115, 075001 (2015)PRLTAO0031-900710.1103/PhysRevLett.115.075001] based on a linear fluid model. In this paper, LC of electron plasma waves is investigated using fully nonlinear Vlasov-Poisson simulations of collisionless bounded plasma. It is shown that, in agreement with the basic theory, plasmons survive substantial transformations of the spectrum and are destroyed only when their wave numbers become large enough to trigger Landau damping. Since nonlinear effects decrease the damping rate, LC is even more efficient when practiced on structures like quasiperiodic Bernstein-Greene-Kruskal (BGK) waves rather than on Langmuir waves per se.
利用等离子体参数的啁啾调制，可以将等离子体波的能量在频谱上上下移动，这可以通过外部场来驱动。根据波谱是离散的（有界等离子体）还是连续的（无界等离子体），这种现象分别称为阶梯爬升（LC）或等离激元的自共振加速。这是由 Barth 等人首次提出的[Phys. Rev. Lett. 115, 075001 (2015)PRLTAO0031-900710.1103/PhysRevLett.115.075001]，基于线性流体模型。在本文中，通过对无碰撞有界等离子体的完全非线性的 Vlasov-Poisson 模拟，研究了电子等离子体波的 LC。结果表明，与基本理论一致，等离激元在频谱的实质性变换中幸存下来，只有当它们的波数变得足够大以引发 Landau 阻尼时才会被破坏。由于非线性效应降低了阻尼率，因此在类似准周期 Bernstein-Greene-Kruskal（BGK）波而不是本身的朗缪尔波的结构上进行 LC 甚至更有效。
