Correlation Reflectometry for Turbulence and Magnetic Field Measurements in Fusion Plasmas
Authors: G.J. Kramer, R. Nazikian, and E. Valeo
Date of PPPL Report: July 2002
Presented at: the Fourteenth Topical Conference on High Temperature Plasma Diagnostics, 8 -11 July 2002, Madison, Wisconsin, USA. Proceedings published in Review of Scientific Instruments 74 No. 3 (March 2003) 1421-1425.
For the interpretation of correlation reflectometry data a fast two-dimensional full wave code has been developed in which realistic plasma geometries are used. Results of this code are compared with experiments and turbulence correlation lengths and fluctuation levels are extracted with statistical optics methods. It is shown that in general the measured reflectometer correlation length is not equal to the turbulence correlation length. The code is also used to study the possibility of O-X correlation reflectometry in FIRE for the determination of the local magnetic field strength. It was found that this is only possible at very low fluctuation levels.