Potential of Electron Cyclotron Emission as Diagnostic Tool on Reversed-Field Pinch

Abstract

Electron cyclotron emission (ECE) is explored as a diagnostic tool for a reversed-field pinch (RFP). There is a sheared magnetic field configuration generated in the RFP because the average poloidal magnetic field is comparable to the average toroidal magnetic field. A theory of electromagnetic wave propagation in plasma confined with a uniform sheared magnetic field is used. A linearly polarized electromagnetic wave undergoes rotation when it propagates through this medium. The plasma anisotropy condition essentially decides the rotation of the electromagnetic wave. The weak plasma anisotropy condition leads to negligible rotation of the propagated wave and the wave preserves the local information. The RFP plasma parameters, for which the very weak anisotropy condition is satisfied, have been determined. These plasma parameters are necessary for the application of ECE as a diagnostic method. The calculation for cyclotron emission intensity is presented. The cyclotron intensity measurement instrumentation is briefly described for the reversed-field experiment (RFX). A calculation to determine the tolerable percentage error generated due to mode scrambling is presented.