A NOVEL SCHEME OF LASER INTERFEROMETER-REFRACTOMETER WITH HIGH SPATIAL AND TEMPORAL RESOLUTIONS

A novel scheme combining interferometer and refractometer for simultan eous plasma density and plasma density gradient measurements is descri bed. The scheme employs a ribbon laser beam obtained from one-dimensio nal laser beam expansion by a pair of cylindrical lenses. This beam sh ape allows measurements at several spatial locations simultaneously. T he beam deflection measurements give additional important information on the spatial distribution of plasma density gradient in the directio n perpendicular to the major axis of the expanded beam. Fast pin photo diodes are used as light detectors for temporal resolution better than 1 ns. The high power (700 mW) of the argon ion laser allows 0.1 degre es phase resolution and simultaneously 0.1 mrad refractional deflectio n angle resolution. (C) 1997 American Institute of Physics.