AN OPTICAL PROBE FOR LOCAL MEASUREMENTS OF FAST PLASMA ION DYNAMICS

A novel insertable probe for local measurements of equilibrium and flu ctuating plasma ion flow velocity and temperature via Doppler spectros copy is described. Optical radiation is collected by two fused silica fiber optic bundles with perpendicular viewlines. Spatial resolution o f about 5 cm is achieved by terminating each view with an optical dump . The collected light is transported by the fiber bundles to a high-re solution spectrometer. Two components of the velocity are measured sim ultaneously-the radial along the insertion of the probe and a perpendi cular component (which can be varied by simply rotating the probe by 9 0 degrees). The accuracy of the velocity measurements is better than 1 km/s. The probe is armored by a boron nitride enclosure and is insert ed into a high temperature plasma to obtain radial profiles of the equ ilibrium and fluctuating plasma velocity. Initial measurements have be en done in Madison Symmetric Torus reversed field pinch. (C) 1998 Amer ican Institute of Physics.