Excitation of an electron Bernstein wave in a magnetized plasma by the optical mixing of two microwave beams

The first experimental evidence of the excitation of an electron Bernstein wave by the nonlinear coupling of two microwave beams in a magnetized plasma is reported. The dependence of the excited wave on the electron density and magnetic field is found in excellent agreement with the dispersion relation of the Bernstein wave. The level measured with an electric probe is typically 3.10^-16 W for a mean incident power of 10 W. This value is about 10 dB below the theoretical value, but still within the uncertainty limit. The resonance width is consistent with the theory.