APPLICATION OF MAXIMUM-ENTROPY METHOD TO DENSITY PROFILE MEASUREMENT VIA MICROWAVE REFLECTOMETRY ON GAMMA-10

The electron density profile has been analysed using the maximum entro py method (MEM) in signal processing of the X-mode microwave reflectom etry carried out in the GAMMA 10 tandem mirror. Although the detected reflectometry signals included the noise components due to density flu ctuations in addition to signal components, the signal components were spectrally separated from the noise components using MEM. Reconstruct ed density profiles are consistent with that obtained from the millime tre wave interferometry measurements assuming a parabolic profile. The present MEM analysis will also be applicable to microwave reflectomet ry experiments on tokamaks or stellarators where signal levels were si gnificantly affected by plasma movement or density perturbations.