Effect of a central barrier potential on asymmetry-induced transport in a coaxial Malmberg–Penning trap

Abstract

Experiments are presented measuring the radial particle flux produced when a central barrier potential is applied to the central ring of a coaxial Malmberg–Penning trap at the same time as the voltages producing the main asymmetry potential ϕ1(r) cos (kz) cos (lθ−ωt). When a negative DC voltage is applied to the entire central ring, the peak flux produced by the main asymmetry is reduced by a factor e(Veff/1.2), where Veff is the effective applied potential in volts. This barrier potential also increases the frequency of this peak flux. When asymmetric ± voltages are applied to the two azimuthally divided halves of the central ring, DC voltages increase the radial flux while AC voltages decrease it. It is shown that these asymmetric barrier voltages produce their own transport and that the resulting modification of the plasma may be a factor in changing the observed flux.