| For the first time, high amplitude (deltan/n ≈ 40%), high stability (Q ≈ 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 differ markedly from plasma waves and Trivelpiece-Gould modes. Excitation behavior responds predictably to tailoring of the electron plasma distribution function, and the multiple-mode structure of excitations can be probed and controlled through spatial and temporal drive configuration. |
