Direct Excitation of High-Amplitude Chirped Bucket-Bgk Modes

Summary form only given. For the first time, high amplitude (Deltan/nap40%), 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 differ markedly from plasma waves and Trivelpiece-Gould modes. Excitation behavior responds predictably to tailoring of the electron plasma distribution function. Preliminary experiments using a fixed-k drive will be discussed.