Banasek J T, Rocco S V R, Potter W M, Byvank T, Kusse B R, Hammer D A
Laboratory of Plasma Studies, Cornell University, Ithaca, New York 14853, USA.
Rev Sci Instrum. 2018 Oct;89(10):10C109. doi: 10.1063/1.5034310.
A single channel sub-nanosecond time-resolved Thomson scattering system used for pulsed power-driven high energy density plasma measurements has been upgraded to give electron temperatures at two different times and from two different angles simultaneously. This system was used to study plasma jets created from a 15 m thick radial Al foil load on a 1 MA pulsed power machine. Two laser pulses were generated by splitting the initial 2.3 ns duration, 10 J, 526.5 nm laser beam into two pulses, each with 2.5 J, and delaying one relative to the other by between 3 and 14 ns. Time resolution within each pulse was obtained using a streak camera to record the scattered spectra from the two beams from two scattering angles. Analysis of the scattering profile showed that the electron temperature of the Al jet increased from 20 eV up to as much as 45 eV within about 2 ns by inverse bremsstrahlung for both laser pulses. The Thomson scattering results from jets formed with opposite current polarities showed different laser heating of the electrons, as well as possibly different ion temperatures. The two-angle scattering determined that the electron density of the plasma jet was at least 2 × 10 cm.
一个用于脉冲功率驱动的高能量密度等离子体测量的单通道亚纳秒时间分辨汤姆逊散射系统已进行升级，可同时在两个不同时刻和从两个不同角度给出电子温度。该系统用于研究由1兆安脉冲功率装置上15米厚的径向铝箔负载产生的等离子体射流。通过将初始持续时间为2.3纳秒、能量为10焦耳、波长为526.5纳米的激光束分成两个能量各为2.5焦耳的脉冲，并使其中一个脉冲相对于另一个脉冲延迟3至14纳秒，从而产生两个激光脉冲。利用条纹相机记录来自两个散射角度的两束光的散射光谱，获得每个脉冲内的时间分辨率。对散射轮廓的分析表明，对于两个激光脉冲，铝射流的电子温度在约2纳秒内通过逆轫致辐射从20电子伏特增加到高达45电子伏特。由相反电流极性形成的射流的汤姆逊散射结果显示出电子的不同激光加热情况，以及可能不同的离子温度。双角度散射确定等离子体射流的电子密度至少为2×10厘米。 （注：原文中“2 × 10 cm”表述有误，推测可能是“2 × 10^n cm”之类，这里按原文翻译）
