Olshansky V. Parametric kinetic instability and plasma turbulence in gas discharges and thermonuclear devices.

In the dissertation the linear and nonlinear stages of ion-sound instability of plasma are investigated. The levels of instability saturation due to induced scattering of ion-sound waves on ions are determined and the rate of turbulent heating of electrons and the effective frequency of electron collisions with ion-sound waves are found. It is shown that turbulent heating of electrons due to ion-sound turbulence can be one of the dominant mechanisms of energy absorption of the pump wave in the helicon plasma source. It is shown that the high efficiency of helicon plasma sources can be associated with the development of both short-wave kinetic ion-sound parametric instability and long-wave. For the first time, implicit physical and numerical models and corresponding computer codes have been developed for self-consistent kinetic modeling of low-pressure plasma discharges in electrostatic and electromagnetic fields. An original numerically stable model for the calculation of electromagnetic fields in the plasma of axisymmetric open traps without taking into account slow waves has been developed. Performed in experiments on the plasma production and heating on a torsatron Uragan-3M (Kharkov, Ukraine) probe measurements of plasma density revealed fluctuations in plasma density with frequencies equal to ion cyclotron harmonics. The penetration of external helical perturbations into the tokamak plasma is investigated. Helical perturbations are used to control the transfer processes at the plasma edge of tokamaks. In the dissertation it is proved that the most dangerous from the point of view of plasma confinement in tokamaks are instabilities of external helical modes, i.e. modes, the resonant surface of which lies outside the plasma. In the dissertation the process of charging of dust grains in low - temperature helicon plasma of low pressure during development of parametric ion - sound instability is investigated for the first time. The behavior of surface electromagnetic waves in the plasma in a magnetic field directed at an angle to the plasma surface has been studied. It is shown for the first time that at nonzero angle of inclination of the magnetic field to the plasma surface, the dispersion curves are significantly deformed.