Status of GAMMA 10/PDX-Thomson scattering system

Abstract

In the tandem mirror GAMMA 10/PDX, a neodymium-doped, yttrium-aluminium-garnet (Nd:YAG) Thomson scattering (TS) system have been constructed for electron temperature and density radial profile measurements. We can successfully measure the radial profiles of electron temperature and density in the central cell of GAMMA 10/PDX by using the YAG-TS system in a single laser shot. By using high speed oscilloscopes and their data collection program, we can measure time dependent electron temperatures and densities every 100 ms in a single plasma shot. Moreover, in order to increase the TS signal intensities, we have constructed a multi-pass TS system of the polarization based system with image relaying optics. The clear multi-pass TS scattering signals from first to eighth passing lasers through the plasma were successfully obtained. The five times larger TS signal intensity were indicated. The multi-pass TS system improves the measurement resolution and time resolution.