Plasma-probe self detection of resonance cones

The near-field resonance cones that extend outward from a small antenna or probe in a magnetoplasma have been detected at a second probe by utilising the nonlinear rectification properties of the probe¿plasma interface. Seen from the point of view of plasma diagnostics, this constitutes a very simple procedure for laboratory measurement of the electron plasma frequency when the electron gyrofrequency is known.