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X-ray observations of tungsten wire array Z-pinch implosions on QiangGuang-1 facility
Zhang Fa-Qiang, Li Zheng-Hong, Xu Ze-Ping, Xu Rong-Kun, Yang Jian-Lun, Guo Cun, Xia Guang-Xin, Chen Jin-Chuan, Song Feng-Jun, Ning Jia-Min, Wang Zhen, Xue Fei-Biao, Li Lin-Bo, Qin Yi, Ying Chun-Tong,
2006, 15 (9):
2058-2064.
doi: 10.1088/1009-1963/15/9/028
Abstract
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PDF (728KB)
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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 1.5MA in 80ns. 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 5×106cm/s and 2.4×107cm/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 1.7×107cm/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.
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