TOMOGRAPHY BY THE MAXIMUM-ENTROPY METHOD FOR THE W7-AS AND W7-X MULTICHANNEL BOLOMETER SYSTEMS

A maximum entropy approach has been applied to the tomographic inversi on of the line integrated measurements of radiation power flux by a mu ltichannel bolometer system. This method was applied to an I-I-mode di scharge in the W7-AS stellarator, with increasing radiation from the p lasma core after the transition being observed. Also, a neutral beam i njection discharge was investigated, and the time evolution of a marfe was documented. This method has also been applied to the preliminary design of a multicamera system for full tomographic reconstruction in the W7-X stellarator. In addition, measurements with wire mesh shielde d metal foil bolometers have been carried out and the shielding of the se bolometers from microwaves produced by the 140 GHz gyrotrons used f or electron cyclotron heating has been demonstrated. (C) 1997 American Institute of Physics.