Neoclassical effects in the annular Penning trap

Neoclassical transport has been investigated with a modified Malmberg-Penni ng trap which has conductors along the axis to create an azimuthal magnetic field. The axial bounce motion of the electrons is accompanied by a radial drift which changes sign at the ends of the device causing drift orbits of finite radial extent. Analysis and numerical simulations show that the tra nsport is neoclassical with mobility and diffusion coefficients depending u pon the axial magnetic field alone rather than the absolute value of the ma gnetic field. Experiments with added helium gas to create electron-neutral collisions show that the electron mobility from an applied radial electric field and the Ware drift from an azimuthal electric field both have neoclas sical values over a wide range of magnetic fields and collision frequencies . (C) 2001 American Institute of Physics.