Center for High Energy Density Science, The University of Texas, Austin, Texas 78712, USA.
Institute for Fusion Studies, The University of Texas, Austin, Texas 78712, USA.
Phys Rev Lett. 2014 Jan 31;112(4):045002. doi: 10.1103/PhysRevLett.112.045002. Epub 2014 Jan 28.
We present experimental evidence supported by simulations of a relativistic ionization wave launched into a surrounding gas by the sheath field of a plasma filament with high energy electrons. Such a filament is created by irradiating a clustering gas jet with a short pulse laser (115 fs) at a peak intensity of 5×10(17) W/cm2. We observe an ionization wave propagating radially through the gas for about 2 ps at 0.2-0.5 c after the laser has passed, doubling the initial radius of the filament. The gas is ionized by the sheath field, while the longevity of the wave is explained by a moving field structure that traps the high energy electrons near the boundary, maintaining a strong sheath field despite the significant expansion of the plasma.
我们提出了实验证据，并通过模拟来支持这一证据，即在由具有高能电子的等离子体细丝鞘场驱动的周围气体中，引发相对论性电离波。这种细丝是通过用短脉冲激光（115fs）以 5×10(17)W/cm2 的峰值强度辐照聚类气体射流而产生的。我们观察到，在激光通过后约 2ps 的时间内，在 0.2-0.5c 的情况下，电离波通过气体径向传播，使细丝的初始半径扩大一倍。气体是由鞘场电离的，而波的持续时间则可以通过一个移动的场结构来解释，该结构将高能电子捕获在边界附近，从而在等离子体显著膨胀的情况下保持较强的鞘场。
