Faraday Rotation of a Far-Infrared Laser Beam by a Small Theta-Pinch Plasma

Abstract

Faraday rotation measurements have been made on a small theta-pinch plasma using the 337, 128, 119, and 79 μm wavelength radiation of the HCN and H2O gas lasers. Rotation angles of up to 50 deg have been measured with an accuracy, set mainly by the laser source, estimated to be better than 10%. Enhancement or attenuation of the transmitted signal produced by density gradients in the plasma has been measured simultaneously to correct the rotation measurements. The Faraday rotation measurement confirms that a magnetic probe placed in the plasma perturbs the actual field present.