Data Report on Material Ablation and Shock Pressure Measurements at ZBL

Lawrence Livermore National Laboratory

关键词: ABLATION;    ALUMINIUM;    ATTENUATION;    CABLES;    HOT SPOTS;    LASERS;    PRESSURE MEASUREMENT;    QUARTZ;    SCHEDULES;    STRESSES;    VALIDATION;   

DOI  :  10.2172/900044
RP-ID  :  UCRL-TR-227274
PID  :  OSTI ID: 900044
Others  :  TRN: US200709%%519

美国|英语

来源: SciTech Connect

【 摘 要 】

A series of tests were conducted on Z-Beamlet Laser (ZBL) to provide data that can be used to determine the laser coupling coefficient and validate code capabilities. The gauges and cables in the chamber were shielded with conduit and resulted in high fidelity signals. The stress measurements show a clear trend of peak stress attenuation with propagation distance, as would be expected. The aluminum sample stresses measured were in the 4 to 8 Kbar range. This constitutes a good data set for model validation. VISAR was considered as a diagnostic for this test series but predicted stress levels were uncertain and we had good success previously with PVDF at this test facility; plus, the aggressive test schedule and limited number of shots left little opportunity to set up this diagnostic. Shock profile measurements were made with both PVDF and Quartz gauges. The PVDF gauge and the Quartz gauge measured very similar shock pulses transmitted through 1.5-mm thick 2024-T3 samples at a nominal fluence of 400 J/cm{sup 2}. The similarity in the two profiles indicates good correlation between measurement techniques and the differences between the sensor areas allow one to evaluate different parts of the beam. The laser beam ablated the front surfaces of the samples. Surface profile measurements of the ablated surface were used to estimate the depth of material removed. Ablated sample surface and crater formation indicate a non-uniform hot spot in the center of the sample.