LIF diagnostics for low temperature and fusion plasmas

Laser induced fluorescence (LIF) techniques allow the measurement of many plasma properties with a high degree of spatial and temporal resolution. The LIF process involves laser excitation of a transition from the ground or a metastable level of an atom, ion or molecule and observation of the subsequent fluorescence from a transition which may be directly or indirectly connected to the excited level. The radiation source is usually a tunable dye laser; cw dye lasers provide very high spectral resolution while pulsed dye lasers achieve high temporal resolution with lesser spectral resolution. The plasma parameters which can be measured using LIF include relative species density, species velocity and electric field. This talk will present results of recent LIF measurements of hydrogen atom temperature in a microwave discharge, ion velocity in a presheath, and electric field in a sheath. The proposed use of LIF to measure electric fields in the H-1 Heliac is also be discussed. (author)