Chapter 3 – High Frequency and Microwave Discharges

An experiment is described in which an electromagnetic wave (extraordinary mode) is propagated across a magnetized plasma and second harmonic generation is detected. The generation of the plasma and the second harmonic wave is associated with resonant conditions of electron cyclotron resonance and upper hybrid resonance. By adjusting the intensity of axial magnetic field, the second harmonic generation can be made solely due to the electron cyclotron resonance, the upper hybrid resonance or both. The experiment is qualitatively in agreement with previous similar experiments and can be explained in terms of the spatial variations of the magnetic field intensity and the electron number density. A technique for diagnosing peak number density is developed from the observed second harmonic power characteristics.

Second harmonic generation in a cyclotron and upper hybrid resonant plasma

An Experimental Investigation of Second Harmonic Generation in a Cyclotron and Upper Hybrid Resonant Plasma

Harmonic generation of an incident extraordinary wave at the upper hybrid and cyclotron frequency in a homogeneous plasma located in a uniform magnetic field was investigated. In the experimental configuration the incident microwave propagated along the density gradient in the direction of decreasing magnetic field such that the harmonic emission was spatially localised.

B. Zanfagna

Papers

Harmonic generation in an inhomogeneous and non-uniformly magnetized plasma.