Institute of Laser Engineering, Osaka University, Suita, Osaka 565-0871, Japan.
Graduate School for the Creation of New Photonics Industries, Hamamatsu, Shizuoka 431-1202, Japan.
Phys Rev E. 2017 Oct;96(4-1):043209. doi: 10.1103/PhysRevE.96.043209. Epub 2017 Oct 16.
The interaction of dense plasmas with an intense laser under a strong external magnetic field has been investigated. When the cyclotron frequency for the ambient magnetic field is higher than the laser frequency, the laser's electromagnetic field is converted to the whistler mode that propagates along the field line. Because of the nature of the whistler wave, the laser light penetrates into dense plasmas with no cutoff density, and produces superthermal electrons through cyclotron resonance. It is found that the cyclotron resonance absorption occurs effectively under the broadened conditions, or a wider range of the external field, which is caused by the presence of relativistic electrons accelerated by the laser field. The upper limit of the ambient field for the resonance increases in proportion to the square root of the relativistic laser intensity. The propagation of a large-amplitude whistler wave could raise the possibility for plasma heating and particle acceleration deep inside dense plasmas.
强磁场下稠密等离子体与强激光的相互作用已经过研究。当环境磁场的回旋频率高于激光频率时，激光的电磁场将转换为沿场线传播的哨声波模式。由于哨声波的性质，激光可以无截止密度地穿透稠密等离子体，并通过回旋共振产生超热电子。研究发现，在扩展条件下，或者由于激光场加速的相对论电子的存在，外部场的更宽范围会使回旋共振吸收有效地发生。共振的环境场上限与相对论激光强度的平方根成正比增加。大振幅哨声波的传播有可能增加稠密等离子体内部的等离子体加热和粒子加速的可能性。
