Resistive-Wall Destabilization of Diocotron Waves

The growth of the negative-energy $l=1\mathrm{}$ diocotron wave has been studied on a column of pure electron plasma. An external $\mathrm{RC}$ circuit connecting sectors of the bounding wall is used to induce growth of the wave, which is otherwise essentially neutrally stable. Such a circuit also causes small shifts in the real part of the wave frequency. The experimentally measured growth rates and frequency shifts are in close agreement with the predictions of theory over a wide range of experimental parameters.