Anomalous Currents to an Electrode in a Magnetoplasma

An electrode pulsed to a large positive potential ($V>>\frac{k{T}_e}{e}$) in a collisionless magnetoplasma is observed to draw currents far in excess (10×) of the field-aligned electron saturation current prescribed by probe theory. The large currents are inferred to be due to anomalous cross-field transport caused by current-driven instabilities. Electric fields due to space-charge separation and anomalous conductivity lead in time to ion expulsion from the current channel and hence to density depletion and current collapse.