Magnetic selfinsulation in vacuum coaxial lines

A quasistationary and wave regimes of energy propagation in vacuum coaxial lines intended for electromagnetic pulse transport from the place of its generation to the target, where a thermonuclear reaction is initiated, are considered. In the quasistationary case are used both a kinetic approach taking into account real particle trajectories and a hydrodynamic one when equations for an averaged electron velocity are utilised. It is shown for the kinetic motion model that in the case of one trajectory type in a real cylindrical geometry with an inner cathode there is no equilibrium in the layer and it can appear only on taking into account several types of trajectories, the induction electric field, the cathode electric field not equal to zero and on neglecting cylindricity effects. In the hydrodynamic approach the equations describing both stationary and nonstationary two-dimensional configurations mainly on neglecting the electron pressure, when the Brillouin approximation is true, are obtained. The behavior of the electron layer in the coaxial waveguide in the framework of the one-dimensional Brillouin approximation is studied. The wave motion in vacuum transmission lines is considered and expressions for the wave front velocity of magnetic selfinsulation, leakage currents and front energy losses in the hydrodynamic model are obtained. The approximate approach to the analysis of the nonlinear wave front structure and the possibility of reflection of magnetic selfinsulation from the coaxial line end are briefly considered. The calculations and experiment show that the transport efficiency in the quasistationary regime is close to 100%, and in the wave regime it is not less than 80%