Study of electron temperature profiles in GDT during neutral beam heating by Thomson scattering system

Thomson scattering system based on a ruby laser was applied in the GDT to m easure the electron temperature during intense neutral beam injection. The system is capable of measuring the radial profile of electron temperature i n the midplane over plasma radii varying from 0 to 12 cm. For this purpose the focusing lens is moved from shot to shot along the laser beam. The scat tered light condenser with the polychromator is correspondingly rotated. An gle of scattering is in the range of 86 - 97 degrees. Thomson scattering sy stem enables measurement of the electron temperature at minimal plasma dens ity of similar to 10(13) cm(-3). The time between shots (about 3 minutes) i s long enough to collect, store the data and subsequently calculate the ele ctron temperature. In the paper, the data on radial profiles and temporal b ehaviour of electron temperature during neutral beam heating at GDT are pre sented. In the experiments, electron temperatures of the target exceeding 1 00 eV was observed.