Improvements to the Ion Doppler Spectrometer Diagnostic on the HIT-SI Experiments

Hossack, Aaron; Chandra, Rian; Everson, Christopher; Jarboe, Thomas

doi:10.1063/1.4990432

Title: Improvements to the Ion Doppler Spectrometer Diagnostic on the HIT-SI Experiments

Journal Article · Fri Mar 09 00:00:00 EST 2018 · Review of Scientific Instruments

DOI:https://doi.org/10.1063/1.4990432· OSTI ID:1422696

^[1];

^[1]; Everson, Christopher ^[1];

^[1]

Univ. of Washington, Seattle, WA (United States)

An Ion Doppler Spectrometer diagnostic system measuring impurity ion temperature and velocity on the HIT-SI and HIT-SI3 spheromak devices has been improved with higher spatiotemporal resolution and lower error than previously described devices. Hardware and software improvements to the established technique have resulted in a record 6.9 µs temporal and <=2.8 cm spatial resolution in the midplane of each device. These allow C III and O II flow, displacement, and temperature profiles to be simultaneously observed. With 72 fused-silica fiber channels in two independent bundles, and an f/8.5 Czerny-Turner spectrometer coupled to video camera, frame-rates of up to ten times the imposed magnetic perturbation frequency of 14.5 kHz were achieved in HIT-SI, viewing the upper 1/2 of the midplane. In HIT-SI3 frame-rates of up to eight times the perturbation frequency were achieved viewing both halves of the midplane. Biorthogonal Decomposition is used as a novel filtering tool, reducing uncertainty in ion temperature from <=13 to <=5 eV (with an instrument temperature of 8-16 eV), and uncertainty in velocity from <=2 to <=1 km/s. Doppler shift and broadening is calculated via the Levenberg-Marquart algorithm, after which errors in velocity and temperature are uniquely specified. Axisymmetric temperature profiles on HIT-SI3 for C III peaked near the inboard current separatrix at approximately 40 eV are observed. Axisymmetric plasma displacement profiles have been measured on HIT-SI3, peaking at approximately 6 cm at the outboard separatrix. Both profiles agree with the upper half of the midplane observable by HIT-SI. With its complete midplane view, HIT-SI3 has unambiguously extracted axisymmetric, toroidal current dependent rotation of up to 3 km/s. Analysis of the temporal phase of the displacement uncovers a coherent structure, locked to the applied perturbation. Previously described diagnostic systems could not achieve such results.

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Research Organization:: Univ. of Washington, Seattle, WA (United States). HIT-Group

Sponsoring Organization:: USDOE Office of Science (SC), Fusion Energy Sciences (FES)

Grant/Contract Number:: FG02-96ER54361

OSTI ID:: 1422696

Alternate ID(s):: OSTI ID: 1425255

Journal Information:: Review of Scientific Instruments, Vol. 89, Issue 3; ISSN 0034-6748

Publisher:: American Institute of Physics (AIP)Copyright Statement

Country of Publication:: United States

Language:: English

References (30)

An Algorithm for Least-Squares Estimation of Nonlinear Parameters Marquardt, Donald W. Journal of the Society for Industrial and Applied Mathematics, Vol. 11, Issue 2 https://doi.org/10.1137/0111030	journal	June 1963
Tomographic inversion techniques incorporating physical constraints for line integrated spectroscopy in stellarators and tokamaks Pablant, N. A.; Bell, R. E.; Bitter, M. Review of Scientific Instruments, Vol. 85, Issue 11 https://doi.org/10.1063/1.4891977	journal	November 2014
Overview of HIT-SI Diagnostic Systems O’Neill, R. G.; Smith, R. J.; Akcay, C. Journal of Fusion Energy, Vol. 26, Issue 1-2 https://doi.org/10.1007/s10894-006-9076-8	journal	December 2006
Combination of multichannel detection and fast time response in a multichord spectrometer Bamford, R. A.; Carolan, P. G.; Bunting, C. A. Review of Scientific Instruments, Vol. 63, Issue 10 https://doi.org/10.1063/1.1143512	journal	October 1992
Plasma response to sustainment with imposed-dynamo current drive in HIT-SI and HIT-SI3 Hossack, A. C.; Jarboe, T. R.; Chandra, R. N. Nuclear Fusion, Vol. 57, Issue 7 https://doi.org/10.1088/1741-4326/aa6ec7	journal	May 2017
2D electron cyclotron emission imaging at ASDEX Upgrade (invited) Classen, I. G. J.; Boom, J. E.; Suttrop, W. Review of Scientific Instruments, Vol. 81, Issue 10 https://doi.org/10.1063/1.3483214	journal	October 2010
A method for the solution of certain non-linear problems in least squares Levenberg, Kenneth Quarterly of Applied Mathematics, Vol. 2, Issue 2 https://doi.org/10.1090/qam/10666	journal	January 1944
Real-time analysis of charge-exchange spectroscopy data at JET Heesterman, P. J. L.; Sall, I.; Giraud, C. Review of Scientific Instruments, Vol. 74, Issue 3 https://doi.org/10.1063/1.1534406	journal	March 2003
The biorthogonal decomposition as a tool for investigating fluctuations in plasmas Dudok de Wit, T.; Pecquet, A. ‐L.; Vallet, J. ‐C. Physics of Plasmas, Vol. 1, Issue 10 https://doi.org/10.1063/1.870481	journal	October 1994
The role of a fast ion component on the heating of the plasma bulk Rapisarda, D.; Zurro, B.; Tribaldos, V. Plasma Physics and Controlled Fusion, Vol. 49, Issue 3 https://doi.org/10.1088/0741-3335/49/3/009	journal	February 2007
Deconvolution of plasma broadened non-hydrogenic neutral atom lines Nikolić, D.; Mijatović, Z.; Djurović, S. Journal of Quantitative Spectroscopy and Radiative Transfer, Vol. 70, Issue 1 https://doi.org/10.1016/S0022-4073(00)00123-0	journal	July 2001
A multi-channel spectroscopic system for measuring impurity ion temperatures and poloidal rotation velocities in TJ-II Baciero, A.; Zurro, B.; McCarthy, K. J. Review of Scientific Instruments, Vol. 72, Issue 1 https://doi.org/10.1063/1.1326008	journal	January 2001
Magnetic analysis of non-circular cross-section tokamaks Luxon, J. L.; Brown, B. B. Nuclear Fusion, Vol. 22, Issue 6 https://doi.org/10.1088/0029-5515/22/6/009	journal	June 1982
Experimental Stark Widths and Shifts for Spectral Lines of Neutral and Ionized Atoms (A Critical Review of Selected Data for the Period 1989 Through 2000) Konjević, N.; Lesage, A.; Fuhr, J. R. Journal of Physical and Chemical Reference Data, Vol. 31, Issue 3 https://doi.org/10.1063/1.1486456	journal	September 2002
Fast high resolution echelle spectroscopy of a laboratory plasma Cothran, C. D.; Fung, J.; Brown, M. R. Review of Scientific Instruments, Vol. 77, Issue 6 https://doi.org/10.1063/1.2212405	journal	June 2006
Determination of plasma-ion velocity distribution via charge-exchange recombination spectroscopy Fonck, R. J.; Darrow, D. S.; Jaehnig, K. P. Physical Review A, Vol. 29, Issue 6 https://doi.org/10.1103/physreva.29.3288	journal	June 1984
Development of validation metrics using biorthogonal decomposition for the comparison of magnetic field measurements Victor, B. S.; Akcay, C.; Hansen, C. J. Plasma Physics and Controlled Fusion, Vol. 57, Issue 4 https://doi.org/10.1088/0741-3335/57/4/045010	journal	March 2015
2D turbulence imaging in DIII-D via beam emission spectroscopy Fenzi, C.; Fonck, R. J.; Jakubowski, M. Review of Scientific Instruments, Vol. 72, Issue 1 https://doi.org/10.1063/1.1321739	journal	January 2001
Imposed-dynamo current drive Jarboe, T. R.; Victor, B. S.; Nelson, B. A. Nuclear Fusion, Vol. 52, Issue 8 https://doi.org/10.1088/0029-5515/52/8/083017	journal	July 2012
Three-dimensional equilibrium reconstruction on the DIII-D device Lazerson, S. A. Nuclear Fusion, Vol. 55, Issue 2 https://doi.org/10.1088/0029-5515/55/2/023009	journal	January 2015
Reduction of plasma density in the Helicity Injected Torus with Steady Inductance experiment by using a helicon pre-ionization source Hossack, Aaron C.; Firman, Taylor; Jarboe, Thomas R. Review of Scientific Instruments, Vol. 84, Issue 10 https://doi.org/10.1063/1.4824707	journal	October 2013
Oxygen ion impurity in the TEXTOR tokamak boundary plasma observed and analysed by Zeeman spectroscopy Hey, J. D.; Chu, C. C.; Brezinsek, S. Journal of Physics B: Atomic, Molecular and Optical Physics, Vol. 35, Issue 6 https://doi.org/10.1088/0953-4075/35/6/309	journal	March 2002
A fast spectroscopic diagnostic for the measurement of plasma impurity ion dynamics Den Hartog, D. J.; Fonck, R. J. Review of Scientific Instruments, Vol. 65, Issue 10 https://doi.org/10.1063/1.1144557	journal	October 1994
Initial studies of steady inductive helicity injection on the HIT-SI experiment Sieck, P. E.; Hamp, W. T.; Izzo, V. A. IEEE Transactions on Plasma Science, Vol. 33, Issue 2 https://doi.org/10.1109/tps.2005.845303	journal	April 2005
X-ray imaging crystal spectroscopy for use in plasma transport research Reinke, M. L.; Podpaly, Y. A.; Bitter, M. Review of Scientific Instruments, Vol. 83, Issue 11 https://doi.org/10.1063/1.4758281	journal	November 2012
The Optimal Hard Threshold for Singular Values is <inline-formula> <tex-math notation="TeX">\(4/\sqrt {3}\) </tex-math></inline-formula> Gavish, Matan; Donoho, David L. IEEE Transactions on Information Theory, Vol. 60, Issue 8 https://doi.org/10.1109/tit.2014.2323359	journal	August 2014
CXRS measurements of ion temperature in NBI discharges on Globus-M spherical tokamak Avdeeva, G. F.; Miroshnikov, I. V.; Bakharev, N. N. Journal of Physics: Conference Series, Vol. 666 https://doi.org/10.1088/1742-6596/666/1/012002	journal	January 2016
Validation of single-fluid and two-fluid magnetohydrodynamic models of the helicity injected torus spheromak experiment with the NIMROD code Akcay, Cihan; Kim, Charlson C.; Victor, Brian S. Physics of Plasmas, Vol. 20, Issue 8 https://doi.org/10.1063/1.4817951	journal	August 2013
Datasets of seed mucilage traits for Arabidopsis thaliana natural accessions with atypical outer mucilage Cambert, Mireille; Berger, Adeline; Sallé, Christine Scientific Data, Vol. 8, Issue 1 https://doi.org/10.1038/s41597-021-00857-3	journal	March 2021
Experimental Stark Widths and Shifts for Spectral Lines of Neutral and Ionized Atoms (A Critical Review of Selected Data for the Period 1989 through 2000) Wiese, Wolfgang L. SPECTRAL LINE SHAPES, AIP Conference Proceedings https://doi.org/10.1063/1.1525443	conference	January 2002