Density jump in helicon discharges

Helicon discharges characteristically exhibit a sharp jump from low to high density as the radiofrequency power is raised. This is usually explained by the transition from an inductively coupled plasma mode to a helicon mode when the dispersion relation for helicon wave propagation is satisfied at a critical power or magnetic field. Experiments have suggested a different mechanism for the sudden jump, a mechanism that depends on overcoming the parasitic circuit losses. This effect is analysed computationally, and agreement with measurements is obtained.