¹ Scientific-Research Institute of Radiophysics at St.Petersburg State University

² Scientific-Research Institute of Physics at St.Petersburg State University
 
 

The experience of plasma investigations shows that passing to non-equilibrium conditions generally results in extension of the range of its properties and in complication of processes. These circumstances impose higher requirements on arsenal of methods and technical facilities for plasma diagnostics. Random character of some non-stationary and heavily non-linear processes in high pressure plasma, for an adequate description of which simultaneous measurement of spatial-temporal distributions of several parameters is necessary, makes the problem of their diagnostics very complicated.

In the frameworks of this type processes it is very interesting, for practical applications and for searching of new physical phenomena as well, to construct a plasma-based device for storage of energy in non-thermal form with relative stability, and to provide conditions for effective supply of it from one channel and for controlled drop of energy in another one. This interest is connected not only with necessity of perfecting of electromagnetic radiation sources but also (and especially) with the problem of ball lightning and is accounted for high energy content of plasma which greatly surpasses possibilities of chemistry-based sources. However solution of the indicated problem in frameworks only of plasma physics is complicated by contradiction of combination of high energy density and low rate of its relaxation.

Since standard diagnostic capabilities have appeared insufficiently informative, long attempts of reproduction of ball lightning in laboratory and of its theoretical understanding only last decades have resulted in outcomes giving hopes for success. These outcomes, based on achievements of science as a whole, determine a circle of phenomena constituting the supposed physical nature of the ball lightning phenomenon and are on the junction of a number of areas of physics, above all of plasma physics and physics of condensed state. According to the available data the basis of the ball lightning is the metastable substance with the energy typical for heavily ionized plasma, while its metastability is determined by relative stability of charges separation characteristic for condensed state of the matter. Such substance should have a low density and exist only at sufficiently low temperature in the form of metal (Manykin E.A. and co-authors) or dielectric (Bychkov V.L.). To the present time the existence of the metastable substance in simplest forms is confirmed experimentally, however, the attained parameters are yet far from the desired and allow to reproduce only some properties of the naturally arising objects. Nevertheless, the analysis of effects observed in experiment is indispensable for further advance of researches.

A considerable part of the obtained results is connected with plasma containing condensed phase. The main method of its creation is erosive electrical discharge of different types. In this paper we present a series of effects which bring to light characteristic features of such plasma, making clear some properties and physical conditions of formation of metastable substance. They demonstrate that the erosive plasma, created in the most non-equilibrium modes, contains metallic, dielectric and metal-dielectric particles binding separated positive and negative charges with high concentration and that mobility of electrons is rather low. In these conditions the role of radiation in energy transfer processes is increased and the plasma is approaching in its properties to metastable substance - dielectric.

A remarkable feature of such plasma is highly expressed switching effect. The erosive radially-slotted discharge is capable to commute the electric currents of high magnitude under the voltages used at the high-voltage lines. It leads us to studying the possibility of creation on the basis of this discharge of a device for lightning protection and of its application in networks of Lenenergo.