Simulation of the motional Stark effect diagnostic gas-filled torus calibration

Many motional Stark effect diagnostics around the world make use of a calibration procedure in which the observed neutral beam is injected into a gas-filled torus with known vacuum fields. The instrument is calibrated by reconciling measured angles with vacuum magnetic reconstructions through a rang...

Full description

Saved in:
Bibliographic Details
Published in:Review of scientific instruments 2008-10, Vol.79 (10), p.10F523-10F523-4
Main Authors: Yuh, Howard Y., Levinton, F. M., Scott, S. D., Ko, J.
Format: Article
Language:English
Subjects:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY
BEAMS
BIREFRINGENCE
CALIBRATION
DOPPLER EFFECT
ELECTRIC POTENTIAL
GEOMETRY
MAGNETIC RECONNECTION
NSTX DEVICE
PLASMA BEAM INJECTION
PLASMA DIAGNOSTICS
PLASMA SIMULATION
POLARIMETERS
POLARIZATION
STARK EFFECT
STRESSES
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Many motional Stark effect diagnostics around the world make use of a calibration procedure in which the observed neutral beam is injected into a gas-filled torus with known vacuum fields. The instrument is calibrated by reconciling measured angles with vacuum magnetic reconstructions through a range of pitch angles. This in situ gas-filled torus calibration most closely approximates the working conditions of the diagnostic and includes effects such as beam and viewing geometries, beam voltages, Faraday and stress induced birefringence (in most cases) of the transmissive optics, as well as the polarimeter response. However, secondary neutrals, produced after ionization then reneutralization of a beam neutral, have been found to contaminate measured angles by emitting Balmer alpha with similar Doppler shifts and Stark polarizations as beam neutrals, but with different polarization angles. Simulation results that show spectral and angle behavior versus calibration parameters such as fill gas pressure will be presented. Data from NSTX and C-Mod will be compared to simulations results.
ISSN:0034-6748
1089-7623
DOI:10.1063/1.2969419