One possibility of H-F sealing of magnetic trap with cusped field

Abstract

The paper analyzes the behaviour of plasma in the region of cusped fields where the magnetostatic field near to the plane of symmetry can be regarded as homogeneous. The case is studied when the motion of the plasma along the lines of force of the magnetostatic field is limited by the effect of the h.f. field of a simple mode. The dynamics of electron and ion gas is studied in the one-particle and linear approximation and it is shown that in the neighbourhood of the plasma-vacuum boundary the plasma particles perform oscillations with limited amplitude only for some values of the parameters of the plasma and external fields. When the gradients of the h.f. field are large these regions of stationary oscillations of plasma are relatively narrow and the interaction between the h.f. field and the plasma is apparent rather as the non-stationary acceleration of plasma. The paper then deals with resonance phenomena. The stability of a plasma-vacuum boundary for the case of stationary equilibrium between the plasma and the h.f. field is investigated on the basis of the MHD approximation. It is seen for the model of a plane boundary that in the case in question, when the lines of force of the magnetostatic field are perpendicular to the plasma boundary, the stability conditions in the first approximation agree with the case when the magnetostatic field is parallel to the boundary. In order to obtain a more exact description of the interaction the paper analyzes the dispersion relation obtained by linearization of the MHD equations for the plasma boundary in the form of an infinitely long cylinder.