MEASUREMENT OF RAYLEIGH-TAYLOR INSTABILITY IN A LASER-ACCELERATED TARGET
MEASUREMENT OF RAYLEIGH-TAYLOR INSTABILITY IN A LASER-ACCELERATED TARGET
复制标题
DOI：
10.1038/299329a0
复制
发表时间：
1982-01-01
期刊：
影响因子：
64.8
通讯作者：
KEY, MH
中科院分区：
文献类型：
--
作者：
COLE, AJ;KILKENNY, JD;KEY, MH
在重力场中支持高密度流体的流体的经典瑞利-泰勒(R-T)不稳定性预计将在激光驱动的压缩中发生。激光产生的高压等离子体加速了Δ厚度的高密度固体壳体。有效引力加速度A将使波数的壳层扰动以R-T速率γ=(Ka)1/2增长。然而，烧蚀效应3-5预计会抑制短波长模，导致最大生长速率atk∼1/Δrand，这意味着对于稳定的内爆有最大的长径比/Δr.在这里，我们提供了第一个明确的实验证据，证明了激光加速的平面靶中R-T不稳定性的增长。这些结果是通过一种新的技术获得的，该技术使用的是初始波纹为Knownk的目标。条纹X射线照相技术可以直接测量由这种初始扰动引起的靶内质量调制的增长。测得外加扰动的时间平均增长率为(0.3±0.05)×(Ka)1/2，与数值模拟结果基本一致。
The classical Rayleigh–Taylor (R–T) instability of a fluid supporting a higher-density fluid1,2in a gravitational field is expected to occur in laser-driven compression3. A laser produces a high-pressure plasma that accelerates a higher-density solid shell of thickness Δrat a ratea. The effective gravitational acceleration–awould cause shell perturbations of wavenumberkto grow at the R–T rateγ= (ka)½. However, ablation effects3–5are predicted to damp short-wavelength modes, giving rise to a maximum growth rate atk∼ 1/Δrand implying a maximum aspect ratior/Δrfor a stable implosion. We present here the first clear experimental evidence for the growth of the R–T instability in a laser-accelerated plane target. These results were obtained by a novel technique using a target with an initial corrugation of knownk. Streak X-ray radiography allows direct measurement of the growth of mass modulations in the target caused by this initial perturbation. The time-averaged growth rate of an imposed perturbation is measured as (0.3±0.05) × (ka)½, in close agreement with a numerical simulation.