Kinetic simulations of scrape-off layer physics in the DIII-D tokamak
Abstract
Simulations using the fully kinetic code XGCa were undertaken to explore the impact of kinetic effects on scrape-o ff layer (SOL) physics in DIII-D H-mode plasmas. XGCa is a total-f, gyrokinetic code which self-consistently calculates the axisymmetric electrostatic potential and plasma dynamics, and includes modules for Monte Carlo neutral transport. Fluid simulations are normally used to simulate the SOL, due to its high collisionality. However, depending on plasma conditions, a number of discrepancies have been observed between experiment and leading SOL fluid codes (e.g. SOLPS),including underestimating outer target temperatures, radial electric field in the SOL, parallel ion SOL flows at the low field side, and impurity radiation. Many of these discrepancies may be linked to the fluid treatment, and might be resolved by including kinetic effects in SOL simulations. The XGCa simulation of the DIII-D tokamak in a nominally sheath-limited regime show many noteworthy features in the SOL. The density and ion temperature are higher at the low- field side, indicative of ion orbit loss. The SOL ion Mach flows are at experimentally relevant levels (Mi 0:5), with similar shapes and poloidal variation as observed in various tokamaks. Surprisingly, the ion Mach flows close to the sheath edge remain subsonic,more »
- Authors:
- Publication Date:
- Research Org.:
- Princeton Plasma Physics Laboratory (PPPL), Princeton, NJ (United States); General Atomics, San Diego, CA (United States)
- Sponsoring Org.:
- USDOE Office of Science (SC), Fusion Energy Sciences (FES)
- OSTI Identifier:
- 1337533
- Alternate Identifier(s):
- OSTI ID: 1349224; OSTI ID: 1373945
- Grant/Contract Number:
- AC02-09CH11466; AC05-00OR22725; FC02-04ER54698
- Resource Type:
- Published Article
- Journal Name:
- Nuclear Materials and Energy
- Additional Journal Information:
- Journal Name: Nuclear Materials and Energy Journal Volume: 12 Journal Issue: C; Journal ID: ISSN 2352-1791
- Publisher:
- Elsevier
- Country of Publication:
- Netherlands
- Language:
- English
- Subject:
- 70 PLASMA PHYSICS AND FUSION TECHNOLOGY
Citation Formats
Churchill, R. M., Canik, J. M., Chang, C. S., Hager, R., Leonard, A. W., Maingi, R., Nazikian, R., and Stotler, D. P. Kinetic simulations of scrape-off layer physics in the DIII-D tokamak. Netherlands: N. p., 2017.
Web. doi:10.1016/j.nme.2016.12.013.
Churchill, R. M., Canik, J. M., Chang, C. S., Hager, R., Leonard, A. W., Maingi, R., Nazikian, R., & Stotler, D. P. Kinetic simulations of scrape-off layer physics in the DIII-D tokamak. Netherlands. https://doi.org/10.1016/j.nme.2016.12.013
Churchill, R. M., Canik, J. M., Chang, C. S., Hager, R., Leonard, A. W., Maingi, R., Nazikian, R., and Stotler, D. P. Tue .
"Kinetic simulations of scrape-off layer physics in the DIII-D tokamak". Netherlands. https://doi.org/10.1016/j.nme.2016.12.013.
@article{osti_1337533,
title = {Kinetic simulations of scrape-off layer physics in the DIII-D tokamak},
author = {Churchill, R. M. and Canik, J. M. and Chang, C. S. and Hager, R. and Leonard, A. W. and Maingi, R. and Nazikian, R. and Stotler, D. P.},
abstractNote = {Simulations using the fully kinetic code XGCa were undertaken to explore the impact of kinetic effects on scrape-o ff layer (SOL) physics in DIII-D H-mode plasmas. XGCa is a total-f, gyrokinetic code which self-consistently calculates the axisymmetric electrostatic potential and plasma dynamics, and includes modules for Monte Carlo neutral transport. Fluid simulations are normally used to simulate the SOL, due to its high collisionality. However, depending on plasma conditions, a number of discrepancies have been observed between experiment and leading SOL fluid codes (e.g. SOLPS),including underestimating outer target temperatures, radial electric field in the SOL, parallel ion SOL flows at the low field side, and impurity radiation. Many of these discrepancies may be linked to the fluid treatment, and might be resolved by including kinetic effects in SOL simulations. The XGCa simulation of the DIII-D tokamak in a nominally sheath-limited regime show many noteworthy features in the SOL. The density and ion temperature are higher at the low- field side, indicative of ion orbit loss. The SOL ion Mach flows are at experimentally relevant levels (Mi 0:5), with similar shapes and poloidal variation as observed in various tokamaks. Surprisingly, the ion Mach flows close to the sheath edge remain subsonic, in contrast to the typical fluid Bohm criterion requiring ion flows to be above sonic at the sheath edge. Related to this are the presence of elevated sheath potentials, eΔΦ=Te 3 > 4, over most of the SOL, with regions in the near-SOL close to the separatrix having eΔΦ =Te > 4. These two results at the sheath edge are a consequence of non-Maxwellian features in the ions and electrons there.},
doi = {10.1016/j.nme.2016.12.013},
journal = {Nuclear Materials and Energy},
number = C,
volume = 12,
place = {Netherlands},
year = {Tue Aug 01 00:00:00 EDT 2017},
month = {Tue Aug 01 00:00:00 EDT 2017}
}
https://doi.org/10.1016/j.nme.2016.12.013
Search WorldCat to find libraries that may hold this journalWeb of Science
Works referencing / citing this record:
Gyrokinetic continuum simulation of turbulence in a straight open-field-line plasma
journal, May 2017
- Shi, E. L.; Hammett, G. W.; Stoltzfus-Dueck, T.
- Journal of Plasma Physics, Vol. 83, Issue 3
Verification of Doppler coherence imaging for 2D ion velocity measurements on DIII-D
journal, September 2018
- Samuell, C. M.; Allen, S. L.; Meyer, W. H.
- Review of Scientific Instruments, Vol. 89, Issue 9
Pressure balance in a lower collisionality, attached tokamak scrape-off layer
journal, July 2019
- Churchill, R. M.; Chang, C. S.; Ku, S.
- Nuclear Fusion, Vol. 59, Issue 9