LIF and absorption in a high electron density plasma

摘要

Laser Induced Fluorescence (LIF) and absorption on the hydrogen Balmer-a line are studied in the magnetized, high electron density (～10~(20) m~(-3)) hydrogen plasma of Pilot-PSI. This plasma generator produces plasma conditions similar to those expected in the diverter of ITER. Experimental yields of the two diagnostics as a function of electron density are compared to a collisional radiative model. At high electron densities, laser induced fluorescence encounters serious competition from electron de-excitation and fluctuations in background emission. A LIF signal could be detected up to an electron density of 1.5.10~(19) m~(-3). Absorption is found to give useful velocity and temperature information over a wide range of electron densities.