Nonuniformly driven two-plasmon-decay instability in direct-drive implosions.
Nonuniformly driven two-plasmon-decay instability in direct-drive implosions.
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DOI：
10.1103/physrevlett.112.145001
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发表时间：
2014-04
影响因子：
8.6
通讯作者：
W. Seka;J. Myatt;R. Short;D. Froula;J. Katz;V. Goncharov;I. Igumenshchev
中科院分区：
文献类型：
--
作者：
W. Seka;J. Myatt;R. Short;D. Froula;J. Katz;V. Goncharov;I. Igumenshchev
半谐波发射光谱和直接驱动内爆期间拍摄的图像表明，双等离激元衰变（TPD）不稳定性在目标表面上不均匀地驱动，并且多束效应主导了这种不稳定性。图像显示了 TPD 不稳定性在空间上的有限程度。显着的光谱特征用于确定日冕中的电子温度。接近阈值时，温度与一维流体动力学预测一致，但超出 TPD 阈值约 10%。二维流体动力学模拟表明，激光强度的很大一部分（~20%）必须被 TPD 不稳定性局部吸收（即通过电子等离子体波的碰撞阻尼）以维持这些温度岛。
Half-harmonic emission spectra and images taken during directly driven implosions show that the two-plasmon decay (TPD) instability is driven nonuniformly over the target surface and that multibeam effects dominate this instability. The images show a spatially limited extent of the TPD instability. A prominent spectral feature is used to determine the electron temperature in the corona. Near threshold the temperatures agree with one-dimensional hydrodynamic predictions but exceed them by ∼10% above the TPD threshold. Two-dimensional hydrodynamic simulations indicate that a significant part (∼20%) of the laser intensity must be locally absorbed by the TPD instability (i.e., by collisional damping of the electron plasma waves) to maintain these temperature islands.