Decoupled recovery of energy and momentum with correction of n = 2 error fields
Abstract
Experiments applying known n = 2 “proxy” error fields (EFs) find that the rotation braking introduced by the proxy EF cannot be completely alleviated through optimal n = 2 correction with poorly matched poloidal spectra. This imperfect performance recovery demonstrates the importance of correcting multiple components of the n = 2 field spectrum and is in contrast to previous results with n = 1 EFs despite similar execution. Measured optimal n = 2 proxy EF correction currents are consistent with those required to null dominant mode coupling to the resonant surfaces and minimize the neoclassical toroidal viscosity (NTV) torque, calculated using ideal MHD plasma response computation. Unlike rotation braking, density pumpout can be fully corrected despite poorly matched spectra, indicating density pumpout is driven only by a single component proportional to the resonant coupling. Through precise n = 2 spectral control density pumpout and rotation braking can thus be decoupled. Rotation braking with n = 2 fields is also found to be proportional to the level of concurrent toroidal rotation, consistent with NTV theory. Lastly, plasmas with modest countercurrent rotation are insensitive to the n = 2 field with neither rotation braking nor density pumpout observed.
- Authors:
-
- General Atomics, San Diego, CA (United States)
- Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
- Columbia Univ., New York, NY (United States)
- Publication Date:
- Research Org.:
- General Atomics, San Diego, CA (United States); Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
- Sponsoring Org.:
- USDOE Office of Science (SC), Fusion Energy Sciences (FES); USDOE Advanced Research Projects Agency - Energy (ARPA-E)
- OSTI Identifier:
- 1350065
- Alternate Identifier(s):
- OSTI ID: 1238921; OSTI ID: 1260743; OSTI ID: 1345402
- Grant/Contract Number:
- AC02-09CH11466; AC05-00OR22725; AC05-06OR23100; FC02-04ER54698; FG02-04ER54761; SC0001961
- Resource Type:
- Accepted Manuscript
- Journal Name:
- Nuclear Fusion
- Additional Journal Information:
- Journal Volume: 55; Journal Issue: 8; Journal ID: ISSN 0029-5515
- Publisher:
- IOP Science
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 70 PLASMA PHYSICS AND FUSION TECHNOLOGY; error fields; plasma response; resonant; magnetic perturbations; neoclassical toroidal viscosity; density pumpout; resonant magnetic perturbations
Citation Formats
Paz-Soldan, Carlos A., Logan, Nikolas C., Lanctot, Matthew J., Hanson, Jeremy M., King, Josh D., La Haye, Robert J., Nazikian, Raffi, Park, Jong -K., and Strait, Edward J. Decoupled recovery of energy and momentum with correction of n = 2 error fields. United States: N. p., 2015.
Web. doi:10.1088/0029-5515/55/8/083012.
Paz-Soldan, Carlos A., Logan, Nikolas C., Lanctot, Matthew J., Hanson, Jeremy M., King, Josh D., La Haye, Robert J., Nazikian, Raffi, Park, Jong -K., & Strait, Edward J. Decoupled recovery of energy and momentum with correction of n = 2 error fields. United States. https://doi.org/10.1088/0029-5515/55/8/083012
Paz-Soldan, Carlos A., Logan, Nikolas C., Lanctot, Matthew J., Hanson, Jeremy M., King, Josh D., La Haye, Robert J., Nazikian, Raffi, Park, Jong -K., and Strait, Edward J. Mon .
"Decoupled recovery of energy and momentum with correction of n = 2 error fields". United States. https://doi.org/10.1088/0029-5515/55/8/083012. https://www.osti.gov/servlets/purl/1350065.
@article{osti_1350065,
title = {Decoupled recovery of energy and momentum with correction of n = 2 error fields},
author = {Paz-Soldan, Carlos A. and Logan, Nikolas C. and Lanctot, Matthew J. and Hanson, Jeremy M. and King, Josh D. and La Haye, Robert J. and Nazikian, Raffi and Park, Jong -K. and Strait, Edward J.},
abstractNote = {Experiments applying known n = 2 “proxy” error fields (EFs) find that the rotation braking introduced by the proxy EF cannot be completely alleviated through optimal n = 2 correction with poorly matched poloidal spectra. This imperfect performance recovery demonstrates the importance of correcting multiple components of the n = 2 field spectrum and is in contrast to previous results with n = 1 EFs despite similar execution. Measured optimal n = 2 proxy EF correction currents are consistent with those required to null dominant mode coupling to the resonant surfaces and minimize the neoclassical toroidal viscosity (NTV) torque, calculated using ideal MHD plasma response computation. Unlike rotation braking, density pumpout can be fully corrected despite poorly matched spectra, indicating density pumpout is driven only by a single component proportional to the resonant coupling. Through precise n = 2 spectral control density pumpout and rotation braking can thus be decoupled. Rotation braking with n = 2 fields is also found to be proportional to the level of concurrent toroidal rotation, consistent with NTV theory. Lastly, plasmas with modest countercurrent rotation are insensitive to the n = 2 field with neither rotation braking nor density pumpout observed.},
doi = {10.1088/0029-5515/55/8/083012},
journal = {Nuclear Fusion},
number = 8,
volume = 55,
place = {United States},
year = {Mon Jul 06 00:00:00 EDT 2015},
month = {Mon Jul 06 00:00:00 EDT 2015}
}
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