Simulations of focusing optics in the McPherson 207 monochromator with the OSLO ray tracing program

Abstract

According to the neoclassical theory, the plasma must rotate in the poloidal and toroidal directions with velocities of the order of 10(5) - 10(6) and 10(6) - 10(7) cm/s, respectively. The poloidal rotation velocity is directly connected to the confinement of energy and particles, whereas the toroidal rotation can contribute to the MHD activity stabilization, in particular the wall resistive modes stabilization, if a certain level of toroidal velocity is achieved. In the Laboratory of Plasma Physics of the IFUSP, a diagnostic based on the Doppler shift of the spectral lines was constructed to estimate the rotation velocity of plasma in the tokamak TCABR. According to [1], both the signal-to-noise ratio of the measured signal and the uncertainty in the velocity measurements are directly related to the linear dispersion of the monochromator used in these measurements. In this project, we intend to use the OSLO ray tracing program to design a new focusing optic for the McPherson 207 monochromator used in the rotation diagnostic. Also is expected that this new focusing optic will reduce the linear dispersion of the monochromator from 12.4 Å / mm to 6.2 Å / mm. (AU)