Local Measurement of the Magnetic-Field Direction in a Laboratory Plasma Using the Optical Mixing of Two Microwave Beams

In a magnetized laboratory plasma, the study of the level of electrostatic electron waves excited by the nonlinear coupling of two microwave beams when the direction of the excited wave vector is varied, allows the orientation of the magnetic field inside the interaction region to be obtained. The waves are detected in situ by probes and the measured accuracy is of 1.5 degrees, using 70 GHz pump sources.