X-ray observations of tungsten wire array Z-pinch implosions on QiangGuang-1 facility

• 来源期刊: 中国物理（英文版）
• 关键词: Z-pinch x-ray wire array R - T instability
• 年，卷（期）: 2006,（9）
• 页码范围: 2058-2064
• 页数: 7页
• 语种: 英文

摘要

Z-pinch experiments with two arrays consisting, respectively, of 32 4-μm- and 6-μm-diameter tungsten wires have been carried out on QiangGuang-1 facility with a current rising up to 1.5 MA in 80 ns. At early time of implosion,x-ray framing images show that the initial emission comes from the central part of arrays, and double clear emission rings, drifting to the anode and the cathode at 5×106 cm/s and 2.4×107 cm/s respectively, are often produced near the electrodes. Later, in a 4-μm-diameter tungsten wire array, filamentation caused by ohmic heating is prominent,and more than ten filaments have been observed. A radial inward shift of arrays starts at about 30 ns earlier than the occurrence of the x-ray peak power for both kinds of arrays, and the shrinkage rate of emission region is as high as 1.7×107 cm/s in a 4-μm-diameter tungsten wire array, which is two times higher than that in a 6-μm one. Emission from precursor plasmas is observed in implosion of 6-μm-diameter tungsten wire arrays, but not in implosion of a 4-μm-diameter tungsten wire array. Whereas, in a 4-μm-diameter tungsten wire array, the soft x-ray emission shows the growth of m=1 instability in the plasma column, which is caused by current. The reasons for the discrepancy between implosions of 4-μm- and 6-μm-diameter tungsten wire arrays are explained.