Ion acceleration by plasma waves excited with a smoothly accelerated electron beam

A principle of exciting a plasma wave with controlled phase velocity capable to capture the considerable number of plasma ions and to accelerate them is studied. The heart of the principle is that in a plasma a group of transverse-hot electrons is formed by external high-frequency pumping on the parametric electron-cyclotron resonance (ECR); the electrons are smoothly accelerated by a longitudinal magnetic field, producing in a plasma an electron beam with increasing phase velocity. Such a beam excites the plasma wave, which at the initial acceleration stage captures considerable part of plasma ions, since the phase velocity for the stage is low, and then accelerates the captured ions. Argon plasma at n=4x109 cm-3 was used in the experiments; the pumping was carried out by TE011 cylindrical standing mode with 2375 MHz frequency, corresponding to the parametric ECR of fundamental mode ω=2 ωsub(ce). It is shown, that the smoothly accelerated electron beam with 1.5 MA current excites a drift wave with the longitudinal velocity up to 1x107 cm/s, forming in a plasma the ion beam with 0.23 MA current and 1 keV ion energy