Broadband radio frequency plasma generation in a Penning-Malmberg trap

Plasma generation is observed in a cylindrical Penning-Malmberg trap in the ultra-high vacuum pressure regime for a large bandwidth of low-power radio frequency (RF) excitations. The process of plasma formation is investigated by measuring the density profiles and a simplified model is developed to characterize the electron heating mechanism. The total charge confined at equilibrium is systematically studied for RF drives in the 0.1-20 MHz range and with different geometrical configurations. With electron densities of some 106 cm-3 at least, the scheme represents an alternative source of non-neutral plasmas for Penning-Malmberg traps.