Advancing local helicity injection for non-solenoidal tokamak startup
Abstract
Experiments on the A ~ 1 PEGASUS ST are advancing the physics and technology basis of Local Helicity Injection (LHI). LHI injects helicity with relatively intense electron current sources in the plasma edge. It creates high toroidal current, toroidally-averaged tokamak-like plasmas that have been efficiently transitioned to Ohmically driven tokamak plasmas. Tradeoffs between physics and engineering goals are tested with LHI systems on the low-field-side and the high-field-side of PEGASUS, producing plasmas predominantly driven by non-solenoidal induction and DC helicity drive, respectively. An extensive LHI source development campaign comparing active arc sources, passive and gas-effused electrode sources lead to the selection of active arc sources for present and next-step LHI deployments. LHI plasmas with net toroidal current Ip=0.225 MA, Te>100 eV, and ne ~ 1019 m-3 are attained to date. A predictive 0D power-balance model describes experimental Ip (t) and partitions the active current drive sources. High-frequency MHD activity is found to be present during LHI current drive, in addition to n=1 modes previously found in NIMROD simulation and experiment. A new system of reduced MHD activity was detected where n=1 activity is suppressed, LHI CD efficiency improves, and long-pulse plasmas are sustained with VIND ~ 0.
- Authors:
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[1];
[1];
[1];
[1];
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[1]
- Univ. of Wisconsin, Madison, WI (United States)
- Publication Date:
- Research Org.:
- Univ. of Wisconsin, Madison, WI (United States)
- Sponsoring Org.:
- USDOE Office of Science (SC), Fusion Energy Sciences (FES)
- OSTI Identifier:
- 1515411
- Grant/Contract Number:
- FG02-96ER54375
- Resource Type:
- Accepted Manuscript
- Journal Name:
- Nuclear Fusion
- Additional Journal Information:
- Journal Volume: 59; Journal Issue: 7; Related Information: M.W. Bongard, G.M. Bodner, M.G. Burke, R.J. Fonck, J.L. Pachicano, J.M. Perry, C. Pierren, J.A. Reusch, A.T. Rhodes, N.J. Richner, C. Rodriguez Sanchez, C.E. Schaefer, and J.D. Weberski, "Public Data Set: Advancing Local Helicity Injection for Non-Solenoidal Tokamak Startup," DOI: 10.18138/1489772; Journal ID: ISSN 0029-5515
- Publisher:
- IOP Science
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 70 PLASMA PHYSICS AND FUSION TECHNOLOGY; helicity injection; tokamak startup; spherical tokamak; current source; magnetohydrodynamics
Citation Formats
Bongard, Michael W., Bodner, Grant M., Burke, Marcus G., Fonck, Raymond J., Pachicano, Jessica L., Perry, Justin M., Pierren, Christopher, Reusch, Joshua A., Rhodes, Alexander T., Richner, Nathan J., Rodriguez Sanchez, Cuauhtemoc, Schaefer, Carolyn E., and Weberski, Justin D. Advancing local helicity injection for non-solenoidal tokamak startup. United States: N. p., 2019.
Web. doi:10.1088/1741-4326/ab17e3.
Bongard, Michael W., Bodner, Grant M., Burke, Marcus G., Fonck, Raymond J., Pachicano, Jessica L., Perry, Justin M., Pierren, Christopher, Reusch, Joshua A., Rhodes, Alexander T., Richner, Nathan J., Rodriguez Sanchez, Cuauhtemoc, Schaefer, Carolyn E., & Weberski, Justin D. Advancing local helicity injection for non-solenoidal tokamak startup. United States. https://doi.org/10.1088/1741-4326/ab17e3
Bongard, Michael W., Bodner, Grant M., Burke, Marcus G., Fonck, Raymond J., Pachicano, Jessica L., Perry, Justin M., Pierren, Christopher, Reusch, Joshua A., Rhodes, Alexander T., Richner, Nathan J., Rodriguez Sanchez, Cuauhtemoc, Schaefer, Carolyn E., and Weberski, Justin D. Wed .
"Advancing local helicity injection for non-solenoidal tokamak startup". United States. https://doi.org/10.1088/1741-4326/ab17e3. https://www.osti.gov/servlets/purl/1515411.
@article{osti_1515411,
title = {Advancing local helicity injection for non-solenoidal tokamak startup},
author = {Bongard, Michael W. and Bodner, Grant M. and Burke, Marcus G. and Fonck, Raymond J. and Pachicano, Jessica L. and Perry, Justin M. and Pierren, Christopher and Reusch, Joshua A. and Rhodes, Alexander T. and Richner, Nathan J. and Rodriguez Sanchez, Cuauhtemoc and Schaefer, Carolyn E. and Weberski, Justin D.},
abstractNote = {Experiments on the A ~ 1 PEGASUS ST are advancing the physics and technology basis of Local Helicity Injection (LHI). LHI injects helicity with relatively intense electron current sources in the plasma edge. It creates high toroidal current, toroidally-averaged tokamak-like plasmas that have been efficiently transitioned to Ohmically driven tokamak plasmas. Tradeoffs between physics and engineering goals are tested with LHI systems on the low-field-side and the high-field-side of PEGASUS, producing plasmas predominantly driven by non-solenoidal induction and DC helicity drive, respectively. An extensive LHI source development campaign comparing active arc sources, passive and gas-effused electrode sources lead to the selection of active arc sources for present and next-step LHI deployments. LHI plasmas with net toroidal current Ip=0.225 MA, Te>100 eV, and ne ~ 1019 m-3 are attained to date. A predictive 0D power-balance model describes experimental Ip (t) and partitions the active current drive sources. High-frequency MHD activity is found to be present during LHI current drive, in addition to n=1 modes previously found in NIMROD simulation and experiment. A new system of reduced MHD activity was detected where n=1 activity is suppressed, LHI CD efficiency improves, and long-pulse plasmas are sustained with VIND ~ 0.},
doi = {10.1088/1741-4326/ab17e3},
journal = {Nuclear Fusion},
number = 7,
volume = 59,
place = {United States},
year = {Wed May 22 00:00:00 EDT 2019},
month = {Wed May 22 00:00:00 EDT 2019}
}
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Noninductively Driven Tokamak Plasmas at Near-Unity Toroidal Beta
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- Bongard, Michael; Bodner, Grant; Burke, Marcus
- University of Wisconsin-Madison
Works referencing / citing this record:
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Public Data Set: Advancing Local Helicity Injection for Non-Solenoidal Tokamak Startup
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- Bongard, Michael; Bodner, Grant; Burke, Marcus
- University of Wisconsin-Madison