The experimental observation and theoretical description of a previously unrecognized mechanism for generating electromagnetic emissions and anomalous resistivity from a beam‐plasma interaction which is characteristic of Penning discharges is reported. Very clear emissions were observed from electric field‐dominated bumpy torus plasma near the geometric mean plasma frequency. These emissions are inconsistent with familiar physical mechanisms, and occurred in excellent agreement with the theoretical frequency &ohgr;gm= 0.537(&ohgr;pe&ohgr;pi)1/2. This frequency was derived from a theory based on the interaction of two opposite, interpenetrating electron beams with a heavy ion plasma. The anomalous resistivity associated with this interaction is predicted to several hundred times that of the familiar Buneman or ’’turbulent’’ resistivity. A perturbation procedure is used to obtain analytic expressions for the emission frequency and the anomalous resistivity in the zero temperature case. These results are extended to include the effects of finite ion temperatures on the dispersive properties of the plasma.