Calculation Characteristics of the Electron Beam Injected into the Plasma of the Open Magnetic Trap GDT

Abstract

In the Institute of Nuclear Physics, SB RAS, experiments are carried out on injection of electron beam into open magnetic trap GDT. The trap is a mirror cell with a large mirror ratio filled with deuterium plasma with subthermonuclear parameters. Two expanders are attached to both sides of the trap. There are volumes with a diverging magnetic field, used to reduce longitudinal losses from the trap. The source of the electron beam is located in the expander, in the region of a weak magnetic field and is exposed to a supersonic plasma ion stream emerging from the trap. The source of a diode-type operates with a thermionic cathode and a hollow metal anode. The plasma from the trap enters the diode through the anode liner and stops by the potential of the cathode, forming an anode electrode. Its surface and the metal surfaces of the electrodes determine the electron-optical characteristics of the diode and the beam formed in it. The paper presents the results of two-dimensional numerical simulation of the beam source and calculated electron beam angular characteristics. The numerical model uses the plasma flow parameters measured in the experiment and results of solving the one-dimensional Poisson equation for the Debye layer on the surface of the anode plasma.