Plasma spectroscopy for magnetically confined fusion plasma

An emission line of neutral helium {lambda}667.8 nm (21P-31D) is observed with a set of line of sights which covers an entire poloidal cross section of LHD, a heliotron-type fusion experimental device. From the observed Zeeman splittings and the well-known magnetic field structure in the plasma, the...

Full description

Saved in:
Bibliographic Details
Main Authors: Goto, M., Morita, S.
Format: Conference Proceeding
Language:English
Subjects:
CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS
CROSS SECTIONS
ELECTRON DENSITY
ELECTRON TEMPERATURE
ELECTRONS
EMISSION SPECTRA
EMISSION SPECTROSCOPY
HELIOTRON
HELIUM
HYDROGEN
LHD DEVICE
LINE BROADENING
MAGNETIC CONFINEMENT
MAGNETIC FIELDS
PHOTON EMISSION
PLASMA
PLASMA DIAGNOSTICS
ZEEMAN EFFECT
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:An emission line of neutral helium {lambda}667.8 nm (21P-31D) is observed with a set of line of sights which covers an entire poloidal cross section of LHD, a heliotron-type fusion experimental device. From the observed Zeeman splittings and the well-known magnetic field structure in the plasma, the emission locations on the line of sight are precisely determined. The distribution of line emissions over the observed poloidal cross section is derived from the results of all the line of sights through a tomographic analysis.Balmer series lines of neutral hydrogen are measured for the rotating radiation body in the Serpens mode [J. Miyazawa et al., Nucl. Fusion 46, 532 (2006)]. The electron temperature and density are derived from the observed spectra with the help of calculations with the collisional-radiative (CR) model. The derived electron density is confirmed with the Stark broadening of several lines from n = 7 to 16 levels, where n is the principal quantum number.We have developed a CR model code for neutral helium based on recently calculated cross section data of electron impact. Six emission lines of neutral helium for the transitions from n = 3 to n = 2 levels are measured for various discharges in LHD and an estimation of the electron temperature and density is attempted from the intensity ratios among three lines, {lambda}667.7 nm (21P-31D), {lambda}706.5 nm (23P-33S), and {lambda}728.1 nm (21P-31S), out of the six lines. Intensities of other three lines, {lambda}388.9 nm (23S-33P), {lambda}501.6 nm (21S-31P), and {lambda}587.6 nm (23P-33D), are calculated with the derived plasma parameters and the agreement with the measured line intensities is found satisfactory.
ISSN:0094-243X
1551-7616
DOI:10.1063/1.2727356