Localized density clumps generated in a magnetized nonneutral plasma

The final, nonlinear, saturated state of the diocotron instability is investigated experimentally in a magnetized, annular, non-neutral plasma. As the wave grows to large amplitude, the plasma is organized into vortices. In the limit of high magnetic fields, and moderate central conductor biases, the diocotron modes compress the plasma into dense (n ∝ 3.5n0) localized clumps. Two-dimensional particle-in-cell computer simulations confirm the physical picture of vortex formation by resonant particle trapping. (orig.)