We apply "rotating wall" electric fields to spin up a non-neutral plasma in a Penning-Malmberg trap, resulting in steady-state confinement (weeks) of up to 10 9 Mg 1 ions. The resulting ion columns can be near global thermal equilibrium, with near-uniform temperature and rotation frequency. The equilibrated plasma E 3 B rotation rate f E is observed to be somewhat less than the drive frequency f w , with slip Df ϵ f w 2 f E depending on temperature as Df~T 1͞2 for 0.05 & T & 5 eV. Dynamic measurements of applied torque versus slip frequency show plasma spin up and compression for Df. 0 and plasma slowing and expansion for Df , 0. By gradually increasing f w , density compression up to 20% of the Brillouin density limit has been achieved. Heating resonances and hysteresis in plasma parameters are also observed.

A “rotating wall” perturbation technique enables confinement of up to 3×109 electrons or 109 ions in Penning–Malmberg traps for periods of weeks. These rotating wall electric fields transfer torque to the particles by exciting Trivelpiece–Gould plasma modes with kz≠0 and mθ=1 or 2. Modes that rotate faster than the plasma column provide a positive torque that counteracts the background drags, resulting in radial plasma compression or steady-state confinement in near-thermal equilibrium states. Conversely, modes that rotate slower than the plasma provide a negative torque, and enhanced plasma expansion is observed. The observed Trivelpiece–Gould mode frequencies are well predicted by linear, infinite-length, guiding-center theory.

A "rotating wall" electric field is shown to give steady-state confinement of a column of 3 3 10 9 electrons in a Penning-Malmberg trap at 4 tesla. By increasing the frequency of the rotating drive, a central-density compression by a factor of 20 has been obtained. For both dipole and quadrupole drives (i.e., m u 1 and 2), the compression rate depends on drive frequency, exhibiting peaks associated with k z fi 0 Trivelpiece-Gould plasma modes. The drive also causes plasma heating, but cyclotron radiation cooling keeps the temperature low enough that background gas ionization is negligible.

Linear Landau damping and nonlinear wave-particle trapping oscillations are observed with standing plasma waves in a trapped pure electron plasma. For low wave amplitudes, the measured linear damping rate agrees quantitatively with linear Landau damping theory. At larger amplitudes, the wave initially damps at the Landau rate, then regrows and oscillates, approaching a steady state, as predicted by O'Neil in 1965 [Phys. Fluids 8, 2255 (1965)]]. This BGK equilibrium is observed to decay slowly due to external dissipation.

We measure the perpendicular-to-parallel collision rate nu perpendicular parallel in laser-cooled magnetized ion plasmas, spanning the uncorrelated to correlated regimes. In correlated regimes, we measure collision rates consistent with the "Salpeter correlation enhancement" of roughly exp(Gamma), for correlation parameters Gamma less, similar 4. This enhancement also applies to fusion in dense plasmas such as stars.