skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Polarization separated Zeeman spectra from magnetic dipole transitions in highly charged argon in the large helical device

Abstract

Visible spectral emission lines from magnetic dipole transitions in Ar X, Ar XI, Ar XIV, and Ar XV are observed from plasmas heated with neutral-beam injection (NBI) in the Large Helical Device [O. Motojima et al., Phys. Plasmas 6, 1843 (1999)]. Orthogonal linearly polarized components of the emission line profiles are observed with a polarization separation optical system and high-resolution spectrometer. Zeeman split profiles reveal polarization characteristics of magnetic dipole transitions. Ion temperatures and emission locations are estimated from the profiles with the magnetic field information on the lines of sight (LOS). The spatially resolved emissions are observed by the array of absolutely calibrated views. The time histories of line profiles and emission intensities at the poloidal view are presented. The observed line profiles and the intensity distribution at the poloidal view indicate the localization of these charge states in the edge region just inside the last closed flux surface. The emission line of Ar X in the tangential observation indicates Doppler shifts of the Zeeman split profiles. The velocity components of Ar X ion flow along the LOS at the tangential view are 7.7 and 2.0 km/s at the outer and inner edge plasmas, respectively, in the opposite directionmore » to the NBI.« less

Authors:
; ; ; ; ;  [1];  [2];  [2]
  1. Department of Mechanical Engineering and Science, Graduate School of Engineering, Kyoto University, Kyoto, 606-8501 (Japan)
  2. (Japan)
Publication Date:
OSTI Identifier:
20974933
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Plasmas; Journal Volume: 14; Journal Issue: 4; Other Information: DOI: 10.1063/1.2714506; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; ARGON; CHARGE STATES; DOPPLER EFFECT; ELECTRON TEMPERATURE; EMISSION; ION TEMPERATURE; LHD DEVICE; M1-TRANSITIONS; MAGNETIC SURFACES; OPTICAL SYSTEMS; PLASMA; PLASMA BEAM INJECTION; PLASMA CONFINEMENT; PLASMA DIAGNOSTICS; POLARIZATION; SPECTRA; SPECTROMETERS; STELLARATORS; ZEEMAN EFFECT

Citation Formats

Iwamae, A., Atake, M., Sakaue, A., Katai, R., Goto, M., Morita, S., Department of Fusion Science, Graduate University for Advanced Studies, Toki, 509-5292, and National Institute for Fusion Science, Toki, 509-5292. Polarization separated Zeeman spectra from magnetic dipole transitions in highly charged argon in the large helical device. United States: N. p., 2007. Web. doi:10.1063/1.2714506.
Iwamae, A., Atake, M., Sakaue, A., Katai, R., Goto, M., Morita, S., Department of Fusion Science, Graduate University for Advanced Studies, Toki, 509-5292, & National Institute for Fusion Science, Toki, 509-5292. Polarization separated Zeeman spectra from magnetic dipole transitions in highly charged argon in the large helical device. United States. doi:10.1063/1.2714506.
Iwamae, A., Atake, M., Sakaue, A., Katai, R., Goto, M., Morita, S., Department of Fusion Science, Graduate University for Advanced Studies, Toki, 509-5292, and National Institute for Fusion Science, Toki, 509-5292. Sun . "Polarization separated Zeeman spectra from magnetic dipole transitions in highly charged argon in the large helical device". United States. doi:10.1063/1.2714506.
@article{osti_20974933,
title = {Polarization separated Zeeman spectra from magnetic dipole transitions in highly charged argon in the large helical device},
author = {Iwamae, A. and Atake, M. and Sakaue, A. and Katai, R. and Goto, M. and Morita, S. and Department of Fusion Science, Graduate University for Advanced Studies, Toki, 509-5292 and National Institute for Fusion Science, Toki, 509-5292},
abstractNote = {Visible spectral emission lines from magnetic dipole transitions in Ar X, Ar XI, Ar XIV, and Ar XV are observed from plasmas heated with neutral-beam injection (NBI) in the Large Helical Device [O. Motojima et al., Phys. Plasmas 6, 1843 (1999)]. Orthogonal linearly polarized components of the emission line profiles are observed with a polarization separation optical system and high-resolution spectrometer. Zeeman split profiles reveal polarization characteristics of magnetic dipole transitions. Ion temperatures and emission locations are estimated from the profiles with the magnetic field information on the lines of sight (LOS). The spatially resolved emissions are observed by the array of absolutely calibrated views. The time histories of line profiles and emission intensities at the poloidal view are presented. The observed line profiles and the intensity distribution at the poloidal view indicate the localization of these charge states in the edge region just inside the last closed flux surface. The emission line of Ar X in the tangential observation indicates Doppler shifts of the Zeeman split profiles. The velocity components of Ar X ion flow along the LOS at the tangential view are 7.7 and 2.0 km/s at the outer and inner edge plasmas, respectively, in the opposite direction to the NBI.},
doi = {10.1063/1.2714506},
journal = {Physics of Plasmas},
number = 4,
volume = 14,
place = {United States},
year = {Sun Apr 15 00:00:00 EDT 2007},
month = {Sun Apr 15 00:00:00 EDT 2007}
}
  • Spectral profiles of the H{sub {alpha}} line emitted from the large helical device plasma [O. Motojima et al., Phys. Plasmas 6, 1843 (1999)] have been measured with polarization-separation optics and a high-resolution spectrometer. Besides the underlying high-temperature component, which probably arises from charge-exchange recombination, the profiles are interpreted as superpositions of Zeeman profiles for two different magnetic field strengths. The emission locations are thus identified on the magnetic field map; the emissions are localized in the inner and outer regions just outside the ergodic layer, and each field-strength contribution to the overall Zeeman profile represents two radiator temperatures, and inwardmore » atom flow velocities in the range of (1-7)x10{sup 3} m/s.« less
  • We have observed an unusual transition which is predicted to result in visible and near-uv emission from very highly charged titaniumlike ions spanning the entire upper half of the periodic table. Measurements of the wavelengths of the 3[ital d][sup 4][ital D][sub 2]-[sup 5][ital D][sub 3] transitions in Ba[sup +34] and Xe[sup +32] are in surprisingly poor agreement with [ital ab] [ital initio] calculations. This work was carried out in an electron beam ion trap and demonstrates that such a device can be an important tool for visible spectroscopy of highly charged ions.
  • The velocity spectra of the negative-ion-(H{sup -}) based neutral beams are studied in high-performance large-area ion sources during injection into large helical device fusion plasmas. We are conducting systematic observations in standard neutral beam injection to correlate beam spectra with source operating conditions. Almost all of the transmitted beam power was at full acceleration energy ({approx}170 keV). The small stripping beam component which was produced in the extraction gap was evaluated to be about 9%-22% by amplitude of the measured spectra for the sources in beam lines 1 and 2. H{sup -} production uniformity from the spectrum profile was 86%-90%more » for three sources. For the longest pulse injection during 74 and 128 s, a full energy component tended to decrease with time, while the accelerator gap stripping tail tended to increase slightly with time, which is attributed to beam-induced outgassing in the accelerator. A higher conductance multislot ground grid accelerator appeared to show little growth in the accelerator gap beam stripping during long pulses compared to the conventional multiaperture ground grid. The beam uniformity appeared to vary in part with the Cs uniformity on the plasma grid.« less
  • Polarization spectroscopy of x-ray lines represents a diagnostic tool to ascertain the presence of electron beams in high-temperature plasmas. Making use of the Livermore electron beam ion trap, which optimizes the linear x-ray line polarization by exciting highly charged ions with a monoenergetic electron beam, we have begun to develop polarization diagnostics and test theoretical models. Our measurement relies on the sensitivity of crystal spectrometers to the linear polarization of x-ray lines which depends on the value of the Bragg angle. We employed two spectrometers with differing analyzing crystals and simultaneously recorded the K-shell emission from heliumlike Fe{sup 24+} andmore » lithiumlike Fe{sup 23+} ions at two different Bragg angles. A clear difference in the relative intensities of the dominant transitions is observed, which is attributed to the amount of linear polarization of the individual lines. {copyright} {ital 1997 American Institute of Physics.}« less
  • Using a pure j-j spherical shell model of beryllium-9, the photoneutron polarization for unpolarized gamma rays is obtained from the E1 + M1 magnetic dipole transition approximation. The result is compared with recent experiment and theoretical models. (C.E.S.)