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Title: A heterodyne dispersion interferometer for wide bandwidth density measurements on DIII-D

Abstract

In order to improve both the density and particularly the temporal resolution beyond previous dispersion interferometers (DIs), a heterodyne technique based on an acousto-optic (AO) cell has been added to the DI. A 40 MHz drive frequency for the AO cell allows density fluctuation measurements into the MHz range. A CO 2 laser-based heterodyne DI (HDI) installed on DIII-D has demonstrated that the HDI is capable of tracking the density evolution throughout DIII-D discharges, including disruption events and other rapid transient phenomena. The data also show good agreement with independent density measurements obtained with the existing DIII-D two-color interferometer. The HDI line-integrated density resolution sampled over a 1 s interval is ~9 × 10 17 m -2. Density fluctuations induced by MHD instabilities are also successfully measured by the HDI.

Authors:
 [1];  [2];  [2]; ORCiD logo [2];  [2]; ORCiD logo [2];  [2];  [2];  [2];  [2];  [3];  [3];  [4]; ORCiD logo [4];  [4];  [5]
  1. National Inst. for Fusion Science, Gifu (Japan)
  2. General Atomics, San Diego, CA (United States)
  3. Palomar College, San Marcos, CA (United States)
  4. Univ. of California, Los Angeles, CA (United States)
  5. California State Univ., San Marcos, CA (United States)
Publication Date:
Research Org.:
General Atomics, San Diego, CA (United States); Tech-X Corporation, Boulder, CO (United States); Princeton Univ., NJ (United States)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
1609191
Alternate Identifier(s):
OSTI ID: 1461569
Grant/Contract Number:  
FC02-04ER54698; FC02-06ER54875; FC02-08ER54972; AC02-09CH11466
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:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; instruments & instrumentation; physics

Citation Formats

Akiyama, T., Van Zeeland, M. A., Boivin, R. L., Carlstrom, T. N., Chavez, J. A., Muscatello, C. M., O’Neill, R., Vasquez, J., Watkins, M., Martin, W., Colio, A., Finkenthal, D. K., Brower, D. L., Chen, J., Ding, W. X., and Perry, M. A heterodyne dispersion interferometer for wide bandwidth density measurements on DIII-D. United States: N. p., 2018. Web. doi:10.1063/1.5037997.
Akiyama, T., Van Zeeland, M. A., Boivin, R. L., Carlstrom, T. N., Chavez, J. A., Muscatello, C. M., O’Neill, R., Vasquez, J., Watkins, M., Martin, W., Colio, A., Finkenthal, D. K., Brower, D. L., Chen, J., Ding, W. X., & Perry, M. A heterodyne dispersion interferometer for wide bandwidth density measurements on DIII-D. United States. doi:10.1063/1.5037997.
Akiyama, T., Van Zeeland, M. A., Boivin, R. L., Carlstrom, T. N., Chavez, J. A., Muscatello, C. M., O’Neill, R., Vasquez, J., Watkins, M., Martin, W., Colio, A., Finkenthal, D. K., Brower, D. L., Chen, J., Ding, W. X., and Perry, M. Tue . "A heterodyne dispersion interferometer for wide bandwidth density measurements on DIII-D". United States. doi:10.1063/1.5037997. https://www.osti.gov/servlets/purl/1609191.
@article{osti_1609191,
title = {A heterodyne dispersion interferometer for wide bandwidth density measurements on DIII-D},
author = {Akiyama, T. and Van Zeeland, M. A. and Boivin, R. L. and Carlstrom, T. N. and Chavez, J. A. and Muscatello, C. M. and O’Neill, R. and Vasquez, J. and Watkins, M. and Martin, W. and Colio, A. and Finkenthal, D. K. and Brower, D. L. and Chen, J. and Ding, W. X. and Perry, M.},
abstractNote = {In order to improve both the density and particularly the temporal resolution beyond previous dispersion interferometers (DIs), a heterodyne technique based on an acousto-optic (AO) cell has been added to the DI. A 40 MHz drive frequency for the AO cell allows density fluctuation measurements into the MHz range. A CO2 laser-based heterodyne DI (HDI) installed on DIII-D has demonstrated that the HDI is capable of tracking the density evolution throughout DIII-D discharges, including disruption events and other rapid transient phenomena. The data also show good agreement with independent density measurements obtained with the existing DIII-D two-color interferometer. The HDI line-integrated density resolution sampled over a 1 s interval is ~9 × 1017 m-2. Density fluctuations induced by MHD instabilities are also successfully measured by the HDI.},
doi = {10.1063/1.5037997},
journal = {Review of Scientific Instruments},
number = 10,
volume = 89,
place = {United States},
year = {2018},
month = {7}
}

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