Persistent Spatially-Driven Kinetic Waves in Pure Electron Plasmas

For the first time, high amplitude ($\Delta $n/n$\approx $40{\%}), high $Q $(up to 100,000) Bernstein, Greene, and Kruskal modes have been controllably excited in a non-neutral electron plasma with a spatially localized electrostatic drive. The modes are created by sweeping an excitation voltage downwards in frequency, thereby dragging a phase space ``bucket'' of low density into the bulk of the plasma velocity distribution. The modes have no linear limit and are instrinsically kinetic in nature. Preliminary experiments using a fixed-k drive for these waves and comparison with kinetic electrostatic electron waves investigated in neutral laser-plasma systems will be presented.