DIAGNOSTIC SYSTEM FOR DETERMINING THE INTERNAL STRUCTURE OF A FIELD REVERSED CONFIGURATION

A set of diagnostics has been developed to determine the structure and internal density profile of a field reversed configuration (FRC) in a nonperturbing manner. The primary diagnostic is a 50-channel tomographic array which uses bremsstrahlung radiation from the FRC in either the visible or near infrared. End-on imaging in both the visible and soft x-ray regions are used to improve inversion accuracy by providing additional information in the form of constraints. A five-channel interferometer will be used as a baseline check on the imaging diagnostic, and provide information on the basic symmetry of the FRC. Up to 80 BΘ probes, with the application of a diagnostic axial current, will be used to detect external changes in separatrix shape. Comparison of diagnostic signals with signals calculated from 3-D MHD simulations will provide for additional determination of internal mode activity.