PLASMA ACCELERATION USING A HIGH FREQUENCY FIELD AND A STATIC MAGNETIC FIELD

The acceleration of a plasma by an intense electromagnetic field and an inhomogeneous static magnetic field was studied. Numerical calculations based on simplified plasma models showed that plasma ions can be accelerated up to 100 keV along the magnetic axis by the use of 1 MW of microwave power and an accelerating structure such as a resonant cavity having a Q-value of 100. Experiments were performed using a 2 MW S-band magnetron, resonant and nonresonant accelerating structures and an external plasma source. In the case of low plasma density (n < 1010 cm-3), the electrons only were accelerated to 100 keV or higher in the neighbourhood of the electron cyclotron resonance. In the case of high plasma density (n similar 10 12-1013 cm-3), ions were accelerated together with electrons and the maximum energy exceeded 100 keV. The dependence of ion energy on the static magnetic field intensity disagreed, however, with the theoretical prediction that the acceleration is most effective in the electron cyclotron resonance region.