Fesenko S. The properties of thermal plasma of electric arc discharge between composite Cu-C electrodes.

Thesis is devoted to experimental studies of the physical peculiarities of thermal plasma of the electric arc discharge between composite Cu-C electrodes. To measure the electric field of the positive plasma column of the arc discharge, it is proposed to use modulation of the interelectrode gap. The method for obtaining radial distributions of electrical conductivity and electron density has been improved and applied for the first time. It is based on the solution of the Elenbaas-Heller equation with the addition of the experimentally obtained electric field of the plasma of the positive column and the temperature distribution. The technique for solving of the nonlinear equations system to obtain the equilibrium plasma composition with account of air components (namely, N2, O2, N, O, NO, N2+, O2+, NO+) is proposed. Based on it, the equilibrium plasma composition of the arc discharge between composite Cu-C and Ag-C electrodes is calculated. It is proposed, the solutions of the equations system, in calculation of the component composition with different sets of experimental input data, can be used to detect a non-equilibrium in plasma and estimate the spatial limit of equilibrium. Nitric oxide molecules with relatively low ionization energies have been found to be important for providing plasma electrical conductivity in the peripheral zone of the arc discharge, where their maximum density is observed. The expansion of the discharge channel between copper-graphite electrodes in comparison with similar discharges between the melting, in particular, one-component copper electrodes is revealed. It is found, that the cause of this phenomenon is the special mechanism of the electrode material erosion in the arc discharge, which is due to the structure of this composite.