Kline J L, Widmann K, Warrick A, Olson R E, Thomas C A, Moore A S, Suter L J, Landen O, Callahan D, Azevedo S, Liebman J, Glenzer S H, Conder A, Dixit S N, Torres P, Tran V, Dewald E L, Kamperschroer J, Atherton L J, Beeler R, Berzins L, Celeste J, Haynam C, Hsing W, Larson D, MacGowan B J, Hinkel D, Kalantar D, Kauffman R, Kilkenny J, Meezan N, Rosen M D, Schneider M, Williams E A, Vernon S, Wallace R J, Van Wonterghem B, Young B K
Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
Rev Sci Instrum. 2010 Oct;81(10):10E321. doi: 10.1063/1.3491032.
The first 96 and 192 beam vacuum Hohlraum target experiments have been fielded at the National Ignition Facility demonstrating radiation temperatures up to 340 eV and fluxes of 20 TW/sr as viewed by DANTE representing an ∼20 times flux increase over NOVA/Omega scale Hohlraums. The vacuum Hohlraums were irradiated with 2 ns square laser pulses with energies between 150 and 635 kJ. They produced nearly Planckian spectra with about 30±10% more flux than predicted by the preshot radiation hydrodynamic simulations. To validate these results, careful verification of all component calibrations, cable deconvolution, and software analysis routines has been conducted. In addition, a half Hohlraum experiment was conducted using a single 2 ns long axial quad with an irradiance of ∼2×10(15) W/cm(2) for comparison with NIF Early Light experiments completed in 2004. We have also completed a conversion efficiency test using a 128-beam nearly uniformly illuminated gold sphere with intensities kept low (at 1×10(14) W/cm(2) over 5 ns) to avoid sensitivity to modeling uncertainties for nonlocal heat conduction and nonlinear absorption mechanisms, to compare with similar intensity, 3 ns OMEGA sphere results. The 2004 and 2009 NIF half-Hohlraums agreed to 10% in flux, but more importantly, the 2006 OMEGA Au Sphere, the 2009 NIF Au sphere, and the calculated Au conversion efficiency agree to ±5% in flux, which is estimated to be the absolute calibration accuracy of the DANTEs. Hence we conclude that the 30±10% higher than expected radiation fluxes from the 96 and 192 beam vacuum Hohlraums are attributable to differences in physics of the larger Hohlraums.
首批96束和192束束流真空黑腔靶实验已在国家点火装置上开展，实验表明，通过DANTE观测到的辐射温度高达340电子伏特，通量为20太瓦/球面度，相较于新星/欧米茄规模的黑腔，通量增加了约20倍。真空黑腔由能量在150至635千焦之间的2纳秒方波激光脉冲辐照。它们产生了近乎普朗克光谱，通量比预实验辐射流体动力学模拟预测的多约30±10%。为验证这些结果，已对所有组件校准、电缆去卷积和软件分析程序进行了仔细核查。此外，还开展了一次半黑腔实验，使用单个2纳秒长的轴向四极装置，辐照度约为2×10¹⁵瓦/平方厘米，以便与2004年完成的国家点火装置早期光实验进行比较。我们还完成了一次转换效率测试，使用一个128束流近乎均匀照明的金球，强度保持较低（在5纳秒内为1×10¹⁴瓦/平方厘米），以避免对非局部热传导和非线性吸收机制的建模不确定性敏感，从而与类似强度的3纳秒欧米茄球实验结果进行比较。2004年和2009年国家点火装置的半黑腔在通量上相差10%，但更重要的是，2006年欧米茄金球实验、2009年国家点火装置金球实验以及计算得出的金转换效率在通量上相差±5%，据估计这就是DANTE的绝对校准精度。因此，我们得出结论，96束和192束束流真空黑腔产生的比预期高30±10%的辐射通量，是由于更大尺寸黑腔物理特性的差异所致。
