Fast Neutral Pressure Measurements in NSTX
Authors: R. Raman, H.W. Kugel, T. Provost, R. Gernhardt, T.R. Jarboe, and M.G. Bell
Date of PPPL Report: August 2002
Presented at: the Fourteenth Topical Conference on High Temperature Plasma Diagnostics, 8-11 July 2002, Madison, Wisconsin, USA. Published in Review of Scientific Instruments 74 No. 3 (March 2003) 1900-1904.
Several fast neutral pressure gauges have been installed on NSTX [National Spherical Torus Experiment] to measure the vessel and divertor pressure during inductive and coaxial helicity injected (CHI) plasma operations. Modified, PDX [Poloidal Divertor Experiment]-type Penning gauges have been installed on the upper and lower divertors. Neutral pressure measurements during plasma operations from these and from two shielded fast Micro ion gauges at different toroidal locations on the vessel mid-plane are described. A new unshielded ion gauge, referred to as the In-vessel Neutral Pressure (INP) gauge is under development.