Title: Effect of the axial magnetic field on a radiating z-pinch plasma
Abstract: Summary form only given. Effect of the axial magnetic field B <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">z</sub> on z-pinch implosion was reported earlier in the Ref. [1-4]. The present research focuses on a systematic study of the effect of the B <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">z</sub> on the total radiation of a bismuth z-pinch and the evolution of the z-pinch instabilities. The experimental setup employs a z-pinch configuration with a preembedded, nearly uniform axial magnetic field of up to 1.35 T. The implosion is driven by a capacitive pulse generator (V=70 kV, C=3.2 μF) capable of storing 7.84 kJ of energy and producing a load current up to 450 kA with a rise time of 450 ns. To judge the stability of the shell implosion, we performed 3-ns time-gated imaging of the visible pinch radiation. A Bi-metal-puff jet [5,6] is injected into a 10-mm anode-cathode gap through a 5-mm diameter collimator. Start diameter of the current sheath exceeds 3 cm. The Bi-metal-puff has a near-normal density distribution. We speculated that the RT instabilities are mitigated with the help of mechanism described in Ref. [7,8]. Note, that the pinch compression has not a strong axisymmetric instabilities during the implosion phase owing to the large start current layer diameter. During the stagnation phase, at B <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">z</sub> =0 we observed the strong MHD instabilities, the maximal pinch radiation was equal to 1.9 kJ (bolometer). At B <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">z</sub> =0.3 T the amplitude of the MHD instabilities decreases slightly during the stagnation phase. While the radiation energy peaked at B <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">z</sub> =0.3 T and it is equal to 2.8 kJ (36 % from the storage energy). At B <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">z</sub> =1.35 T the radiation falls up to 0.25 kJ; the plasma column has the diameter about 0.5 cm and it was stable during the stagnation phase. We compared our data with the results of the 1D RMHD simulation.
Publication Year: 2015
Publication Date: 2015-05-01
Language: en
Type: article
Indexed In: ['crossref']
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