Experimental study of plasma focusing in erosion plasma accelerators. V. Mechanism of plasma focusing in a magnetoplasma compressor
Experimental results are reported from a study of the dynamics, microscopic structure, and stability of successive developmental stages of high-current plasmodynamic discharges in magnetoplasma compressors of the erosion type under conditions of intense radiation transport. Particular attention was given to the transient stage of plasma focusing behind the cutoff of the accelerating channel, and to secondary pinching processes in the second half-period of the discharge current and methods for analyzing them when limited diagnostic facilities are available. It is shown that thermal instabilities, which dominate during the stages of formation and quasisteady flow in the compressed zone, do not cause the nonideal discharge plasma to have anomalous thermodynamic and transport properties; the accelerated plasma, which is thermalized in the compressed zone, is macroscopically stable when the current shell interacts with the relatively cold vapor (this interaction is accompanied by development of an intense shock-wave structure and power instabilities in various modes). It is demonstrated that either an inertial + Hall mechanism of plasma focusing or two-stage inertial compression of the plasma is possible, regardless of the chemical composition and ionization state of the electric discharge plasma. In the two-stage method of plasma compression, the plasma is compressed toward the central anode in the accelerating channel by the Hall effect and as a result of additional pinching in the outgoing Z currents; when energy is input to the MHD compression zone in a self-consistent manner, this makes it possible to control the dimensions and the dynamic and energy characteristics of the plasma stream.
- Research Organization:
- N. E. Bauman Higher Technical Institute, Moscow
- OSTI ID:
- 6300547
- Journal Information:
- Sov. Phys. - Tech. Phys. (Engl. Transl.); (United States), Vol. 27:8
- Country of Publication:
- United States
- Language:
- English
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