Initial development of ponderomotive filaments in plasma from intense hot spots produced by a random phase plate
Initial development of ponderomotive filaments in plasma from intense hot spots produced by a random phase plate
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随机相位板产生的强热点等离子体中有质动力丝的初步发展
DOI：
10.1063/1.860629
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发表时间：
1993
期刊：
影响因子：
--
通讯作者：
D. Dubois
中科院分区：
文献类型：
--
作者：
H. Rose;D. Dubois
激光束中的局部强度峰值（热点）可能会引发自聚焦，而不是线性不稳定性。如果热点功率P包含临界功率Pc的数倍，并且如果等离子体密度n与临界密度nc相比较小，则在小于穿过热点半径的声学渡越时间τia的时间尺度上，热点塌陷，捕获初始热点功率的阶数单位。塌缩时间被确定为P/Pc和τia的普适函数。聚焦区域以最初的超音速向激光移动，并且随着其传播而减速。该后向传播焦点的功率单调减小，直到达到临界功率。这种限制性的、最浅的焦点在比τia长的时间尺度上发展，并且对应于在具有电响应离子的模型中获得的焦点。对于低密度等离子体，非线性离子效应终止崩溃和瞬态强度放大的约束作为一个普遍的…
Local intensity peaks, hot spots, in laser beams may initiate self‐focusing, in lieu of linear instabilities. If the hot spot power, P, contains several times the critical power, Pc, and if the plasma density, n, is small compared to the critical density, nc, then on a time scale less than an acoustic transit time across the hot spot radius, τia, the hot spot collapses, capturing order unity of the initial hot spot power. The collapse time is determined as a universal function of P/Pc and τia. The focal region moves towards the laser with an initially supersonic speed, and decelerates as it propagates. The power of this back propagating focus decreases monotonically until the critical power is reached. This limiting, shallowest, focus develops on a time scale long compared to τia and corresponds to the focus obtained in a model with adiabatically responding ions. For low‐density plasma nonlinear ion effects terminate collapse and a bound on the transient intensity amplification is obtained as a universal ...