Millimeter-wave interferometry and far-forward scattering for density fluctuation measurements on LTX-β
Abstract
The λ ≈ 1 mm (f = 288 GHz) interferometer for the Lithium Tokamak Experiment-β (LTX-β) will use a chirped-frequency source and a centerstack-mounted retro-reflector mirror to provide electron line density measurements along a single radial chord at the midplane. The interferometer is unique in the use of a single source (narrow-band chirped-frequency interferometry) and a single beam splitter for separating and recombining the probe and reference beams. The current work provides a documentation of the interferometry hardware and evaluates the capabilities of the system as a far-forward collective scattering diagnostic. As such, the current optical setup is estimated to have a detection range of 0.4 ≲ k⊥ ≲ 1.7 cm–1, while an improved layout will extend the upper k⊥ limit to ~3 cm–1. Measurements with the diagnostic on LTX are presented, showing interferometry results and scattered signal data. Furthermore, these diagnostics are expected to provide routine measurements on LTX-β for high frequency coherent density oscillations (e.g., Alfvénic modes during neutral beam injection) as well as for broadband turbulence.
- Authors:
-
- Univ. of California, Los Angeles, CA (United States)
- Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
- Publication Date:
- Research Org.:
- Princeton Plasma Physics Laboratory (PPPL), Princeton, NJ (United States)
- Sponsoring Org.:
- USDOE
- OSTI Identifier:
- 1484244
- Alternate Identifier(s):
- OSTI ID: 1470793
- Grant/Contract Number:
- AC02-09CH11466; FG02-99ER54527
- Resource Type:
- Accepted Manuscript
- Journal Name:
- Review of Scientific Instruments
- Additional Journal Information:
- Journal Volume: 89; Journal Issue: 10; Journal ID: ISSN 0034-6748
- Publisher:
- American Institute of Physics (AIP)
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 47 OTHER INSTRUMENTATION
Citation Formats
Kubota, S., Majeski, R., Boyle, D. P., Kaita, R., Kozub, T., Lantsov, R., Merino, E., Nguyen, X. V., Peebles, W. A., and Rhodes, T. L. Millimeter-wave interferometry and far-forward scattering for density fluctuation measurements on LTX-β. United States: N. p., 2018.
Web. doi:10.1063/1.5039418.
Kubota, S., Majeski, R., Boyle, D. P., Kaita, R., Kozub, T., Lantsov, R., Merino, E., Nguyen, X. V., Peebles, W. A., & Rhodes, T. L. Millimeter-wave interferometry and far-forward scattering for density fluctuation measurements on LTX-β. United States. https://doi.org/10.1063/1.5039418
Kubota, S., Majeski, R., Boyle, D. P., Kaita, R., Kozub, T., Lantsov, R., Merino, E., Nguyen, X. V., Peebles, W. A., and Rhodes, T. L. Fri .
"Millimeter-wave interferometry and far-forward scattering for density fluctuation measurements on LTX-β". United States. https://doi.org/10.1063/1.5039418. https://www.osti.gov/servlets/purl/1484244.
@article{osti_1484244,
title = {Millimeter-wave interferometry and far-forward scattering for density fluctuation measurements on LTX-β},
author = {Kubota, S. and Majeski, R. and Boyle, D. P. and Kaita, R. and Kozub, T. and Lantsov, R. and Merino, E. and Nguyen, X. V. and Peebles, W. A. and Rhodes, T. L.},
abstractNote = {The λ ≈ 1 mm (f = 288 GHz) interferometer for the Lithium Tokamak Experiment-β (LTX-β) will use a chirped-frequency source and a centerstack-mounted retro-reflector mirror to provide electron line density measurements along a single radial chord at the midplane. The interferometer is unique in the use of a single source (narrow-band chirped-frequency interferometry) and a single beam splitter for separating and recombining the probe and reference beams. The current work provides a documentation of the interferometry hardware and evaluates the capabilities of the system as a far-forward collective scattering diagnostic. As such, the current optical setup is estimated to have a detection range of 0.4 ≲ k⊥ ≲ 1.7 cm–1, while an improved layout will extend the upper k⊥ limit to ~3 cm–1. Measurements with the diagnostic on LTX are presented, showing interferometry results and scattered signal data. Furthermore, these diagnostics are expected to provide routine measurements on LTX-β for high frequency coherent density oscillations (e.g., Alfvénic modes during neutral beam injection) as well as for broadband turbulence.},
doi = {10.1063/1.5039418},
journal = {Review of Scientific Instruments},
number = 10,
volume = 89,
place = {United States},
year = {Fri Sep 14 00:00:00 EDT 2018},
month = {Fri Sep 14 00:00:00 EDT 2018}
}
Web of Science
Works referenced in this record:
Performance projections for the lithium tokamak experiment (LTX)
journal, April 2009
- Majeski, R.; Berzak, L.; Gray, T.
- Nuclear Fusion, Vol. 49, Issue 5
Density fluctuation measurements by far-forward collective scattering in the MST reversed-field pinch
journal, October 2012
- Ding, W. X.; Lin, L.; Duff, J. R.
- Review of Scientific Instruments, Vol. 83, Issue 10
Compatibility of lithium plasma-facing surfaces with high edge temperatures in the Lithium Tokamak Experiment
journal, May 2017
- Majeski, R.; Bell, R. E.; Boyle, D. P.
- Physics of Plasmas, Vol. 24, Issue 5
Study of density fluctuations in plasmas by small-angle CO2 laser scattering
journal, January 1980
- Slusher, R. E.; Surko, C. M.
- Physics of Fluids, Vol. 23, Issue 3
Beam tracing in inhomogeneous anisotropic plasmas
journal, October 1998
- Pereverzev, G. V.
- Physics of Plasmas, Vol. 5, Issue 10
Assessment of microwave power flow for reflectometry measurements in tokamak plasmas
journal, January 2008
- Gourdain, P-A; Peebles, W. A.
- Plasma Physics and Controlled Fusion, Vol. 50, Issue 2
Far-forward collective scattering measurements of density fluctuations in the helically symmetric experiment stellarator
journal, October 2010
- Deng, C. B.; Brower, D. L.
- Review of Scientific Instruments, Vol. 81, Issue 10
Exploration of spherical torus physics in the NSTX device
journal, March 2000
- Ono, M.; Kaye, S. M.; Peng, Y. -K. M.
- Nuclear Fusion, Vol. 40, Issue 3Y
Far infrared laser polarimetry and far forward scattering diagnostics for the C-2 field reversed configuration plasmas
journal, November 2014
- Deng, B. H.; Kinley, J. S.; Knapp, K.
- Review of Scientific Instruments, Vol. 85, Issue 11
Observation of Flat Electron Temperature Profiles in the Lithium Tokamak Experiment
journal, July 2017
- Boyle, D. P.; Majeski, R.; Schmitt, J. C.
- Physical Review Letters, Vol. 119, Issue 1
A frequency-modulated continuous-wave reflectometer for the Lithium Tokamak Experiment
journal, May 2017
- Kubota, S.; Majeski, R.; Peebles, W. A.
- Review of Scientific Instruments, Vol. 88, Issue 5
Fourier optics approach to far forward scattering and related refractive index phenomena in laboratory plasmas
journal, July 1982
- Evans, D. E.; Hellermann, M. von; Holzhauer, E.
- Plasma Physics, Vol. 24, Issue 7
Characterization of a Dual-Mode Horn for Submillimeter Wavelengths (Short Papers)
journal, August 1984
- Pickett, H. M.; Hardy, J. C.; Farhoomand, J.
- IEEE Transactions on Microwave Theory and Techniques, Vol. 32, Issue 8
Diffraction of a Gaussian beam at an aperture
journal, January 1990
- Ediss, G. A.
- IEE Proceedings H Microwaves, Antennas and Propagation, Vol. 137, Issue 3
Far-forward collective scattering measurements by FIR polarimeter-interferometer on J-TEXT tokamak
journal, August 2016
- Shi, P.; Chen, J.; Gao, L.
- Review of Scientific Instruments, Vol. 87, Issue 11
Applications of the Fraunhofer-diffraction method for plasma-wave measurements
journal, October 1983
- Sonoda, Y.; Suetsugu, Y.; Muraoka, K.
- Plasma Physics, Vol. 25, Issue 10
Design and operation of a low cost, reliable millimeter-wave interferometer
journal, January 1999
- Porte, L.; Rettig, C. L.; Peebles, W. A.
- Review of Scientific Instruments, Vol. 70, Issue 1
Multichannel interferometer system for the helically symmetric experiment
journal, January 2001
- Brower, D. L.; Deng, C.; Ding, W. X.
- Review of Scientific Instruments, Vol. 72, Issue 1