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Description
This paper demonstrates experimentally recorded peculiarities of a dynamical Z-pinch powered with the current from a magneto-cumulative generator. The overmass load represents a cylindrical multiwire array consisted of 680 tungsten wires of diameter d=11 µm and length l=1.5 cm (total mass M=4.14 mg). The wires were evenly located on a cylindrical surface of the radius R=3 cm. Maximum amplitude of a current passed through the load was I≈4.3 MA (current rise time τ ≈0.9 µs on a level of 0.1…0.9). That was significantly lower than the current of ~14 MA that was used in optimal implosion regime of arrays with such initial mass and radius.
In spite of significantly underpowering of the load, in the experiment we recorded soft x-ray radiation (SXR) pulse that have characteristic full width at a half maximum of ~10 ns and energy of several hundreds of kilojoules.
Two-dimensional magneto-hydrodynamic (MHD) code FLUX-rz (developed in RFNC-VNIIEF) was used for numerical simulation and analysis of the obtained results. The calculation-physical model includes the radiation transfer in a multi-group diffuse approximation [1]. The process of a substance ablation from the array wires under the influence of the conducting current is described in the model of prolonged plasma formation [2].
Performed simulation allowed to find a number of peculiarities of the overmass load implosion and reproduce the main SXR pulses parameters (implosion time, full width at a half maximum, irradiated energy) that were recorded with scintillation detectors, and derive the plasma temperature of the pinch.
References
[1]. B.G. Repin, A.P. Orlov, P.B. Repin, and V.D. Selemir // IEEE Trans. on Plasma Science, 2010, v.38, № 8, pp.1822-1827.
[2]. B.G. Repin, A.P. Orlov // Int. Conf. XII Khariton’s Topical Sci. Readings, Dig. Tech. Papers, Sarov, Russia, 2010, pp. 526–531.
