7 research outputs found
Design of a 3rd harmonic electron cyclotron emission diagnostic for ballooning mode fluctuations in PBX-M
A third harmonic electron cyclotron emission diagnostic using ultrawide bandwidth ( = 40 GHz) heterodyne receivers centered on 120 GHz with 14 channels per radial view is describecj for localized, long wavelength (5 % X s 50 cm), fast time response ( = 1 ps) fluctuation studies in the PBX-M tokamak. The optically gray emission signal will have a y ie/ne + (3/0)Te/Te dependence on temperature and density fluctuations where y S 1 and 1 _ P: 3 depending on local optical depth. Electron temperature fluctuation sensitivity is estimated to be 0.2 % se ' Te/Te s 2.9 % depending on local optical depth and fluctuation frequency in the 0.1-1 MHz range. Spatial resolution of approximately 3 cm radially and 5 cm vertically are estimated for 2 keV plasmas with low suprathermal electron emission