Novel analysis technique for measuring edge density fluctuation profiles with reflectometry in the Large Helical Device
Abstract
A new method for measuring density fluctuation profiles near the edge of plasmas in the Large Helical Device (LHD) has been developed utilizing reflectometry combined with pellet-induced fast density scans. Reflectometer cutoff location was calculated by proportionally scaling the cutoff location calculated with fast far infrared laser interferometer (FIR) density profiles to match the slower time resolution results of the ray-tracing code LHD-GAUSS. Plasma velocity profile peaks generated with this reflectometer mapping were checked against velocity measurements made with charge exchange spectroscopy (CXS) and were found to agree within experimental uncertainty once diagnostic differences were accounted for. Measured density fluctuation profiles were found to peak strongly near the edge of the plasma, as is the case in most tokamaks. These measurements can be used in the future to inform inversion methods of phase contrast imaging (PCI) measurements. This result was confirmed with both a fixed frequency reflectometer and calibrated data from a multi-frequency comb reflectometer, and this method was applied successfully to a series of discharges. The full width at half maximum of the turbulence layer near the edge of the plasma was found to be only 1.5–3 cm on a series of LHD discharges, less than 5% of themore »
- Authors:
-
[1];
[2];
- Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States). Plasma Science and Fusion Center
- National Inst. for Fusion Science, Toki, Gifu (Japan)
- Australian National Univ., Canberra, ACT (Australia). Plasma Research Lab.
- Publication Date:
- Research Org.:
- Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)
- Sponsoring Org.:
- USDOE Office of Science (SC)
- OSTI Identifier:
- 1474379
- Alternate Identifier(s):
- OSTI ID: 1371794
- Grant/Contract Number:
- SC0006419
- Resource Type:
- Accepted Manuscript
- Journal Name:
- Review of Scientific Instruments
- Additional Journal Information:
- Journal Volume: 88; Journal Issue: 7; Journal ID: ISSN 0034-6748
- Publisher:
- American Institute of Physics (AIP)
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 70 PLASMA PHYSICS AND FUSION TECHNOLOGY; 47 OTHER INSTRUMENTATION
Citation Formats
Creely, A. J., Ida, K., Yoshinuma, M., Tokuzawa, T., Tsujimura, T., Akiyama, T., Sakamoto, R., Emoto, M., Tanaka, K., and Michael, C. A. Novel analysis technique for measuring edge density fluctuation profiles with reflectometry in the Large Helical Device. United States: N. p., 2017.
Web. doi:10.1063/1.4993437.
Creely, A. J., Ida, K., Yoshinuma, M., Tokuzawa, T., Tsujimura, T., Akiyama, T., Sakamoto, R., Emoto, M., Tanaka, K., & Michael, C. A. Novel analysis technique for measuring edge density fluctuation profiles with reflectometry in the Large Helical Device. United States. https://doi.org/10.1063/1.4993437
Creely, A. J., Ida, K., Yoshinuma, M., Tokuzawa, T., Tsujimura, T., Akiyama, T., Sakamoto, R., Emoto, M., Tanaka, K., and Michael, C. A. Wed .
"Novel analysis technique for measuring edge density fluctuation profiles with reflectometry in the Large Helical Device". United States. https://doi.org/10.1063/1.4993437. https://www.osti.gov/servlets/purl/1474379.
@article{osti_1474379,
title = {Novel analysis technique for measuring edge density fluctuation profiles with reflectometry in the Large Helical Device},
author = {Creely, A. J. and Ida, K. and Yoshinuma, M. and Tokuzawa, T. and Tsujimura, T. and Akiyama, T. and Sakamoto, R. and Emoto, M. and Tanaka, K. and Michael, C. A.},
abstractNote = {A new method for measuring density fluctuation profiles near the edge of plasmas in the Large Helical Device (LHD) has been developed utilizing reflectometry combined with pellet-induced fast density scans. Reflectometer cutoff location was calculated by proportionally scaling the cutoff location calculated with fast far infrared laser interferometer (FIR) density profiles to match the slower time resolution results of the ray-tracing code LHD-GAUSS. Plasma velocity profile peaks generated with this reflectometer mapping were checked against velocity measurements made with charge exchange spectroscopy (CXS) and were found to agree within experimental uncertainty once diagnostic differences were accounted for. Measured density fluctuation profiles were found to peak strongly near the edge of the plasma, as is the case in most tokamaks. These measurements can be used in the future to inform inversion methods of phase contrast imaging (PCI) measurements. This result was confirmed with both a fixed frequency reflectometer and calibrated data from a multi-frequency comb reflectometer, and this method was applied successfully to a series of discharges. The full width at half maximum of the turbulence layer near the edge of the plasma was found to be only 1.5–3 cm on a series of LHD discharges, less than 5% of the normalized minor radius.},
doi = {10.1063/1.4993437},
journal = {Review of Scientific Instruments},
number = 7,
volume = 88,
place = {United States},
year = {Wed Jul 19 00:00:00 EDT 2017},
month = {Wed Jul 19 00:00:00 EDT 2017}
}
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Works referenced in this record:
Improved understanding of physics processes in pedestal structure, leading to improved predictive capability for ITER
journal, August 2013
- Groebner, R. J.; Chang, C. S.; Hughes, J. W.
- Nuclear Fusion, Vol. 53, Issue 9
<i>Ka</i>-band Microwave Frequency Comb Doppler Reflectometer System for the Large Helical Device
journal, January 2014
- Tokuzawa, Tokihiko; Inagaki, Shigeru; Ejiri, Akira
- Plasma and Fusion Research, Vol. 9, Issue 0
Beam emission spectroscopy as a comprehensive plasma diagnostic tool
journal, October 1993
- Mandl, W.; Wolf, R. C.; Hellermann, M. G. von
- Plasma Physics and Controlled Fusion, Vol. 35, Issue 10
The phase-contrast technique as an imaging diagnostic for plasma density fluctuations
journal, May 1985
- Weisen, H.
- Infrared Physics, Vol. 25, Issue 3
Two-dimensional phase contrast imaging for local turbulence measurements in large helical device (invited)
journal, October 2008
- Tanaka, K.; Michael, C. A.; Vyacheslavov, L. N.
- Review of Scientific Instruments, Vol. 79, Issue 10
Development and application of a ray-tracing code integrating with 3D equilibrium mapping in LHD ECH experiments
journal, November 2015
- Ii Tsujimura, T.; Kubo, S.; Takahashi, H.
- Nuclear Fusion, Vol. 55, Issue 12
ECH Power Deposition Study in the Collisionless Plasma of LHD
conference, January 2003
- Kubo, S.
- PLASMA PHYSICS: 11th International Congress on Plasma Physics: ICPP2002, AIP Conference Proceedings
Measurements of poloidal rotation velocity using charge exchange spectroscopy in a large helical device
journal, June 2000
- Ida, K.; Kado, S.; Liang, Y.
- Review of Scientific Instruments, Vol. 71, Issue 6
Doppler reflectometry for the investigation of propagating density perturbations
journal, October 2001
- Hirsch, M.; Holzhauer, E.; Baldzuhn, J.
- Plasma Physics and Controlled Fusion, Vol. 43, Issue 12
Microwave Doppler reflectometer system in LHD
journal, October 2012
- Tokuzawa, T.; Ejiri, A.; Kawahata, K.
- Review of Scientific Instruments, Vol. 83, Issue 10
Characteristics of edge plasma turbulence on the ATF torsatron
journal, April 1991
- Uckan, T.; Hidalgo, C.; Bell, J. D.
- Physics of Fluids B: Plasma Physics, Vol. 3, Issue 4
Measurements of Micro-Turbulence in High Beta and High Density Regimes of LHD and Comparison with Resistive G-Mode Scaling
journal, January 2008
- Michael, Clive; Tanaka, Kenji; Vyacheslavov, Leonid
- Plasma and Fusion Research, Vol. 3, Issue 0
Quantitative predictions of tokamak energy confinement from first‐principles simulations with kinetic effects
journal, June 1995
- Kotschenreuther, M.; Dorland, W.; Beer, M. A.
- Physics of Plasmas, Vol. 2, Issue 6
Current status of the LHD Thomson scattering system
journal, May 2012
- Yamada, I.; Narihara, K.; Funaba, H.
- Journal of Instrumentation, Vol. 7, Issue 05
Charge-Exchange Spectroscopy with Pitch-Controlled Double-Slit Fiber Bundle on LHD
journal, August 2010
- Yoshinuma, M.; Ida, K.; Yokoyama, M.
- Fusion Science and Technology, Vol. 58, Issue 1
Multifrequency channel microwave reflectometer with frequency hopping operation for density fluctuation measurements in Large Helical Device
journal, October 2010
- Tokuzawa, T.; Ejiri, A.; Kawahata, K.
- Review of Scientific Instruments, Vol. 81, Issue 10
Design and construction of a far infrared laser interferometer for the LHD
journal, March 1997
- Kawahata, K.; Ejiri, A.; Tanaka, K.
- Fusion Engineering and Design, Vol. 34-35
Development and application of real-time magnetic coordinate mapping system in the Large Helical Device
journal, December 2012
- Suzuki, C.; Ida, K.; Suzuki, Y.
- Plasma Physics and Controlled Fusion, Vol. 55, Issue 1
Recent advances in the LHD experiment
journal, December 2003
- Motojima, O.; Ohyabu, N.; Komori, A.
- Nuclear Fusion, Vol. 43, Issue 12
Spatial distribution of turbulence in the Wendelstein 7-AS stellarator
journal, August 2002
- Basse, N. P.; Michelsen, P. K.; Zoletnik, S.
- Plasma Sources Science and Technology, Vol. 11, Issue 3A
Density fluctuation measurements in ATF using correlation reflectometry
journal, September 1992
- Hanson, G. R.; Harris, J. H.; Wilgen, J. B.
- Nuclear Fusion, Vol. 32, Issue 9
Phase contrast imaging interferometer for edge density fluctuation measurements on LHD
journal, March 2003
- Tanaka, K.; Vyacheslavov, L. N.; Akiyama, T.
- Review of Scientific Instruments, Vol. 74, Issue 3
Two-dimensional wave-number spectral analysis techniques for phase contrast imaging turbulence imaging data on large helical device
journal, September 2015
- Michael, C. A.; Tanaka, K.; Vyacheslavov, L.
- Review of Scientific Instruments, Vol. 86, Issue 9
Recent results on turbulence and MHD activity achieved by reflectometry
journal, November 2006
- Sabot, R.; Clairet, F.; Conway, G. D.
- Plasma Physics and Controlled Fusion, Vol. 48, Issue 12B
Plasma rotation profile measurements using Doppler reflectometry
journal, April 2004
- Conway, G. D.; Schirmer, J.; Klenge, S.
- Plasma Physics and Controlled Fusion, Vol. 46, Issue 6
CO2 laser based two-volume collective scattering instrument for spatially localized turbulence measurements
journal, June 2001
- Saffman, M.; Zoletnik, S.; Basse, N. P.
- Review of Scientific Instruments, Vol. 72, Issue 6
Overview of LHD experiments
journal, October 2001
- Fujiwara, M.; Kawahata, K.; Ohyabu, N.
- Nuclear Fusion, Vol. 41, Issue 10
Works referencing / citing this record:
Spatial structure of low-frequency fluctuations throughout the transition of poloidal flow velocity in edge plasmas of LHD
journal, September 2019
- Moon, C.; Kobayashi, T.; Ida, K.
- Physics of Plasmas, Vol. 26, Issue 9
On the interplay between MHD instabilities and turbulent transport in magnetically confined plasmas
journal, October 2019
- Ida, K.
- Plasma Physics and Controlled Fusion, Vol. 62, Issue 1
Exhaust of turbulence cloud at the tongue shaped deformation event
journal, October 2018
- Ida, K.; Kobayashi, T.; Tokuzawa, T.
- Nuclear Fusion, Vol. 58, Issue 11