The measurement of ion acoustic turbulence and reduced thermal conductivity caused by a large temperature gradient in a laser heated plasma
The measurement of ion acoustic turbulence and reduced thermal conductivity caused by a large temperature gradient in a laser heated plasma
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激光加热等离子体中大温度梯度引起的离子声湍流和热导率降低的测量
DOI：
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发表时间：
1980
期刊：
影响因子：
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通讯作者：
J. Kilkenny
中科院分区：
文献类型：
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作者：
D. R. Gray;J. Kilkenny
给出了密度为6×1016 cm-3的均匀预制等离子体被聚焦于1011W cm-2的10.6微米辐射加热的实验结果。红宝石激光散射给出了合成密度和温度的空间和时间分辨测量，显示出高达λe mod Delta T mod/T=0.5的大温度梯度。观测到了增强的低频湍流。与一维计算机程序相比，观察到的温度梯度表明，热流被限制在自由流动极限的4+或-2%，但吸收是经典逆韧致辐射吸收速率的1.1+或-0.5倍。观测到的Te/Ti和λe mod Delta T mod/T足以激发热流驱动的离子声学湍流，这解释了观测到的低频湍流。这一湍流水平被证明足够大，足以解释观测到的导热系数。
An extensive account is given of experiments in which an homogeneous preformed plasma of density 6*1016 cm-3 was heated by 10.6 mu m radiation focused on 1011 W cm-2. Ruby laser scattering gave space and time resolved measurements of the resultant density and temperature, showing large temperature gradients up to lambda e mod Delta T mod /T=0.5. Enhanced low frequency turbulence was observed. When compared with a one dimensional computer code, the observed temperature gradients imply that the heat flux was limited to 4+or-2% of the free streaming limit but that the absorption was 1.1+or-0.5 times the classical inverse bremsstrahlung absorption rate. The observed Te/Ti and lambda e mod Delta T mod /T were sufficient to excite heat flux driven ion acoustic turbulence, which explains the observed low frequency turbulence. This turbulence level is shown to be large enough to account for the observed thermal conductivity.