Centre for Plasma Physics, The Queens University of Belfast, Belfast BT7 1NN, United Kingdom.
Phys Rev Lett. 2011 Jul 8;107(2):025003. doi: 10.1103/PhysRevLett.107.025003. Epub 2011 Jul 6.
A two-dimensional numerical study of the expansion of a dense plasma through a more rarefied one is reported. The electrostatic ion-acoustic shock, which is generated during the expansion, accelerates the electrons of the rarefied plasma inducing a superthermal population which reduces electron thermal anisotropy. The Weibel instability is therefore not triggered and no self-generated magnetic fields are observed, in contrast with published theoretical results dealing with plasma expansion into vacuum. The shock front develops a filamentary structure which is interpreted as the consequence of the electrostatic ion-ion instability, consistently with published analytical models and experimental results.
本文报道了稠密等离子体通过稀薄等离子体膨胀的二维数值研究。在膨胀过程中产生的静电离子声激波会加速稀薄等离子体的电子，导致电子产生热各向异性降低的超热成分。因此，不会触发 Weibel 不稳定性，也不会观察到自生磁场，这与处理等离子体向真空中膨胀的已发表理论结果形成对比。激波前沿呈现出丝状结构，这被解释为静电离子-离子不稳定性的结果，与已发表的分析模型和实验结果一致。
