Investigation of the mechanism of effective collisionless ion beam-plasma interaction in a transverse magnetic field

Excitation of longitudinal oscillations of the low-hybrid branch in a plasma by an ion beam injected across a magnetic field has been studied. The spectrum and increments of the excited oscillations and their effect of the beam velocity distribution function have been examined under the following conditions: plasma density from 109 to 1010 cm-3, electron temperature about 10 eV, ion temperature about 1 eV, monoenergetic beam current from 1 to 2 mA, energy from 0 to 500 eV, magnetic field up to 300 Oe and flight length 10 cm. The optimum conditions instability development correspond to the plasma density and magnetic field with the ratio of cyclotron electron frequency to plasma electron one being ωsub(He)/ωsub(pe) < or approximately 1. In nonlinear regions the beam ion velocity spectrum becomes plateau-like, i.e. thermalization of the beam in the plasma is practically achieved. Such effects may occur in thermonuclear traps with external injection