Effects of collisional ion orbit loss on neoclassical tokamak radial electric fields

Zhu, Hongxuan; Stoltzfus-Dueck, T.; Hager, R.; Ku, S.; Chang, C. S.

doi:10.1088/1741-4326/ac5b8a

Effects of collisional ion orbit loss on neoclassical tokamak radial electric fields

Journal Article · Tue Apr 05 00:00:00 EDT 2022 · Nuclear Fusion

DOI:https://doi.org/10.1088/1741-4326/ac5b8a· OSTI ID:1856202

^[1]; ^[1]; Hager, R. ^[1]; Ku, S. ^[1]; Chang, C. S. ^[1]

Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)

We report that ion orbit loss is considered important for generating the radially inward electric field E_r in a tokamak edge plasma. In particular, this effect is emphasized in diverted tokamaks with a magnetic X point. In neoclassical equilibria, Coulomb collisions can scatter ions onto loss orbits and generate a radially outward current, which in steady state is balanced by the radially inward current from viscosity. To quantitatively measure this loss-orbit current in an edge pedestal, an ion-orbit-flux diagnostic has been implemented in the axisymmetric version of the gyrokinetic particle-in-cell code XGC. As the first application of this diagnostic, a neoclassical DIII-D H-mode plasma is studied using gyrokinetic ions and adiabatic electrons. The validity of the diagnostic is demonstrated by studying the collisional relaxation of E_r in the core. After this demonstration, the loss-orbit current is numerically measured in the edge pedestal in quasisteady state. In this plasma, it is found that the radial electric force on ions from E_r approximately balances the ion radial pressure gradient in the edge pedestal, with the radial force from the plasma flow term being a minor component. The effect of orbit loss on E_r is found to be only mild.

View Accepted Manuscript (DOE)

Research Organization:: Princeton Plasma Physics Laboratory (PPPL), Princeton, NJ (United States)

Sponsoring Organization:: USDOE Office of Science (SC); SciDAC-4

Grant/Contract Number:: AC02-09CH11466; AC02-05CH11231

OSTI ID:: 1856202

Journal Information:: Nuclear Fusion, Journal Name: Nuclear Fusion Journal Issue: 6 Vol. 62; ISSN 0029-5515

Publisher:: IOP ScienceCopyright Statement

Country of Publication:: United States

Language:: English

References (49)

Effects of collisional ion orbit loss on neoclassical tokamak radial electric fields Zhu, Hongxuan; Stoltzfus-Dueck, T.; Hager, R. Princeton Plasma Physics Laboratory (PPPL), Princeton, NJ (United States) https://doi.org/10.11578/1888260	dataset	January 2022
Mesh generation for confined fusion plasma simulation Zhang, Fan; Hager, Robert; Ku, Seung-Hoe Engineering with Computers, Vol. 32, Issue 2 https://doi.org/10.1007/s00366-015-0417-y	journal	September 2015
A new hybrid-Lagrangian numerical scheme for gyrokinetic simulation of tokamak edge plasma Ku, S.; Hager, R.; Chang, C. S. Journal of Computational Physics, Vol. 315 https://doi.org/10.1016/j.jcp.2016.03.062	journal	June 2016
A fully non-linear multi-species Fokker–Planck–Landau collision operator for simulation of fusion plasma Hager, Robert; Yoon, E. S.; Ku, S. Journal of Computational Physics, Vol. 315 https://doi.org/10.1016/j.jcp.2016.03.064	journal	June 2016
Direction of ion ∇B drift and power threshold in high confinement mode in diverted tokamaks Shaing, K. C. Physics of Plasmas, Vol. 9, Issue 1 https://doi.org/10.1063/1.1428326	journal	January 2002
X-transport: A baseline nonambipolar transport in a diverted tokamak plasma edge Chang, C. S.; Kue, Seunghoe; Weitzner, H. Physics of Plasmas, Vol. 9, Issue 9 https://doi.org/10.1063/1.1490348	journal	September 2002
Some Toroidal Equilibria for Plasma under Magnetoelectric Confinement Stix, Thomas H. Physics of Fluids, Vol. 14, Issue 3 https://doi.org/10.1063/1.1693490	journal	January 1971
Transport properties of a toroidal plasma at low-to-intermediate collision frequencies Hinton, F. L. Physics of Fluids, Vol. 16, Issue 6 https://doi.org/10.1063/1.1694436	journal	January 1973
Rotation of a toroidally confined, collisional plasma Hazeltine, R. D. Physics of Fluids, Vol. 17, Issue 5 https://doi.org/10.1063/1.1694838	journal	January 1974
Numerical study of neoclassical plasma pedestal in a tokamak geometry Chang, C. S.; Ku, Seunghoe; Weitzner, H. Physics of Plasmas, Vol. 11, Issue 5 https://doi.org/10.1063/1.1707024	journal	May 2004
Property of an X-point generated velocity-space hole in a diverted tokamak plasma edge Ku, Seunghoe; Baek, Hoyul; Chang, C. S. Physics of Plasmas, Vol. 11, Issue 12 https://doi.org/10.1063/1.1812273	journal	December 2004
Spontaneous rotation sources in a quiescent tokamak edge plasma Chang, C. S.; Ku, S. Physics of Plasmas, Vol. 15, Issue 6 https://doi.org/10.1063/1.2937116	journal	June 2008
Energetic consistency and momentum conservation in the gyrokinetic description of tokamak plasmas Scott, B.; Smirnov, J. Physics of Plasmas, Vol. 17, Issue 11 https://doi.org/10.1063/1.3507920	journal	November 2010
Intrinsic rotation generation in ELM-free H-mode plasmas in the DIII-D tokamak—Experimental observations Müller, S. H.; Boedo, J. A.; Burrell, K. H. Physics of Plasmas, Vol. 18, Issue 7 https://doi.org/10.1063/1.3605041	journal	July 2011
The effect of ion orbit loss and X-loss on the interpretation of ion energy and particle transport in the DIII-D edge plasma Stacey, Weston M. Physics of Plasmas, Vol. 18, Issue 10 https://doi.org/10.1063/1.3640506	journal	October 2011
A Fokker-Planck-Landau collision equation solver on two-dimensional velocity grid and its application to particle-in-cell simulation Yoon, E. S.; Chang, C. S. Physics of Plasmas, Vol. 21, Issue 3 https://doi.org/10.1063/1.4867359	journal	March 2014
Kinetic neoclassical transport in the H-mode pedestal Battaglia, D. J.; Burrell, K. H.; Chang, C. S. Physics of Plasmas, Vol. 21, Issue 7 https://doi.org/10.1063/1.4886803	journal	July 2014
Intrinsic momentum generation by a combined neoclassical and turbulence mechanism in diverted DIII-D plasma edge Seo, Janghoon; Chang, C. S.; Ku, S. Physics of Plasmas, Vol. 21, Issue 9 https://doi.org/10.1063/1.4894242	journal	September 2014
Thermal ion orbit loss and radial electric field in DIII-D deGrassie, J. S.; Boedo, J. A.; Grierson, B. A. Physics of Plasmas, Vol. 22, Issue 8 https://doi.org/10.1063/1.4928558	journal	August 2015
Experimental evidence of edge intrinsic momentum source driven by kinetic ion loss and edge radial electric fields in tokamaks Boedo, J. A.; deGrassie, J. S.; Grierson, B. Physics of Plasmas, Vol. 23, Issue 9 https://doi.org/10.1063/1.4962683	journal	September 2016
A fast low-to-high confinement mode bifurcation dynamics in the boundary-plasma gyrokinetic code XGC1 Ku, S.; Chang, C. S.; Hager, R. Physics of Plasmas, Vol. 25, Issue 5 https://doi.org/10.1063/1.5020792	journal	May 2018
A geometric model of ion orbit loss under the influence of a radial electric field Brzozowski, Robert W.; Jenko, Frank; Bilato, Roberto Physics of Plasmas, Vol. 26, Issue 4 https://doi.org/10.1063/1.5075613	journal	April 2019
Relaxation rate of poloidal rotation in the banana regime in tokamaks Shaing, K. C.; Hirshman, S. P. Physics of Fluids B: Plasma Physics, Vol. 1, Issue 3 https://doi.org/10.1063/1.859134	journal	March 1989
An estimate of the ion orbit loss rate in tokamaks Shaing, K. C. Physics of Fluids B: Plasma Physics, Vol. 4, Issue 10 https://doi.org/10.1063/1.860385	journal	October 1992
Ion orbit loss and poloidal plasma rotation in tokamaks Shaing, K. C. Physics of Fluids B: Plasma Physics, Vol. 4, Issue 1 https://doi.org/10.1063/1.860430	journal	January 1992
Neoclassical rotation of tokamak plasmas in the plateau regime Novakovskii, S. V.; Galeev, A. A.; Liu, C. S. Physics of Plasmas, Vol. 2, Issue 10 https://doi.org/10.1063/1.871054	journal	October 1995
Plateau regime dynamics of the relaxation of poloidal rotation in tokamak plasmas Lebedev, V. B.; Yushmanov, P. N.; Diamond, P. H. Physics of Plasmas, Vol. 3, Issue 8 https://doi.org/10.1063/1.871638	journal	August 1996
The neoclassical theory of poloidal flow damping in a tokamak Morris, R. C.; Haines, M. G.; Hastie, R. J. Physics of Plasmas, Vol. 3, Issue 12 https://doi.org/10.1063/1.872068	journal	December 1996
Constructing a new predictive scaling formula for ITER's divertor heat-load width informed by a simulation-anchored machine learning Chang, C. S.; Ku, S.; Hager, R. Physics of Plasmas, Vol. 28, Issue 2 https://doi.org/10.1063/5.0027637	journal	February 2021
The ambipolarity paradox in toroidal diffusion, revisited Hirshman, S. P. Nuclear Fusion, Vol. 18, Issue 7 https://doi.org/10.1088/0029-5515/18/7/004	journal	July 1978
Neoclassical transport of impurities in tokamak plasmas Hirshman, S. P.; Sigmar, D. J. Nuclear Fusion, Vol. 21, Issue 9 https://doi.org/10.1088/0029-5515/21/9/003	journal	September 1981
Loss ion orbits at the tokamak edge Chankin, A. V.; McCracken, G. M. Nuclear Fusion, Vol. 33, Issue 10 https://doi.org/10.1088/0029-5515/33/10/i05	journal	October 1993
Direct ion orbit loss near the plasma edge of a divertor tokamak in the presence of a radial electric field Miyamoto, K. Nuclear Fusion, Vol. 36, Issue 7 https://doi.org/10.1088/0029-5515/36/7/i09	journal	July 1996
Intrinsic toroidal velocity near the edge of DIII-D H-mode plasmas deGrassie, J. S.; Groebner, R. J.; Burrell, K. H. Nuclear Fusion, Vol. 49, Issue 8 https://doi.org/10.1088/0029-5515/49/8/085020	journal	July 2009
L- to H-mode transitions at low density in ASDEX Upgrade Sauter, P.; Pütterich, T.; Ryter, F. Nuclear Fusion, Vol. 52, Issue 1 https://doi.org/10.1088/0029-5515/52/1/012001	journal	December 2011
High-accuracy characterization of the edge radial electric field at ASDEX Upgrade Viezzer, E.; Pütterich, T.; Conway, G. D. Nuclear Fusion, Vol. 53, Issue 5 https://doi.org/10.1088/0029-5515/53/5/053005	journal	April 2013
Evidence for the neoclassical nature of the radial electric field in the edge transport barrier of ASDEX Upgrade Viezzer, E.; Pütterich, T.; Angioni, C. Nuclear Fusion, Vol. 54, Issue 1 https://doi.org/10.1088/0029-5515/54/1/012003	journal	December 2013
Co-current rotation of the bulk ions due to the ion orbit loss at the edge of a tokamak plasma Pan, Chengkang; Wang, Shaojie; Ou, Jing Nuclear Fusion, Vol. 54, Issue 10 https://doi.org/10.1088/0029-5515/54/10/103003	journal	September 2014
Relaxation rate of poloidal rotation in the banana regime Taguchi, M. Plasma Physics and Controlled Fusion, Vol. 33, Issue 7 https://doi.org/10.1088/0741-3335/33/7/008	journal	July 1991
A review of theories of the L-H transition Connor, J. W.; Wilson, H. R. Plasma Physics and Controlled Fusion, Vol. 42, Issue 1 https://doi.org/10.1088/0741-3335/42/1/201	journal	December 1999
Orbit-modulated transport and sources in time-dependent plasmas Stoltzfus-Dueck, T.; Zhu, Hongxuan Plasma Physics and Controlled Fusion, Vol. 63, Issue 11 https://doi.org/10.1088/1361-6587/ac2034	journal	September 2021
Momentum flux parasitic to free-energy transfer Stoltzfus-Dueck, T.; Scott, B. Nuclear Fusion, Vol. 57, Issue 8 https://doi.org/10.1088/1741-4326/aa7289	journal	July 2017
Orbit-modulated plasma transport and sources Stoltzfus-Dueck, T. Nuclear Fusion, Vol. 60, Issue 1 https://doi.org/10.1088/1741-4326/ab5339	journal	December 2019
The physics of the mean and oscillating radial electric field in the L–H transition: the driving nature and turbulent transport suppression mechanism Kobayashi, T. Nuclear Fusion, Vol. 60, Issue 9 https://doi.org/10.1088/1741-4326/ab7a67	journal	July 2020
Experimental Investigation of the Role of Fluid Turbulent Stresses and Edge Plasma Flows for Intrinsic Rotation Generation in DIII-D H -Mode Plasmas Müller, S. H.; Boedo, J. A.; Burrell, K. H. Physical Review Letters, Vol. 106, Issue 11 https://doi.org/10.1103/physrevlett.106.115001	journal	March 2011
Transport-Driven Toroidal Rotation in the Tokamak Edge Stoltzfus-Dueck, T. Physical Review Letters, Vol. 108, Issue 6 https://doi.org/10.1103/physrevlett.108.065002	journal	February 2012
Fast Low-to-High Confinement Mode Bifurcation Dynamics in a Tokamak Edge Plasma Gyrokinetic Simulation Chang, C. S.; Ku, S.; Tynan, G. R. Physical Review Letters, Vol. 118, Issue 17 https://doi.org/10.1103/physrevlett.118.175001	journal	April 2017
Model of L to H -Mode Transition in Tokamak Itoh, Sanae-I.; Itoh, Kimitaka Physical Review Letters, Vol. 60, Issue 22 https://doi.org/10.1103/physrevlett.60.2276	journal	May 1988
Bifurcation theory of poloidal rotation in tokamaks: A model for L-H transition Shaing, K.; Crume, E. Physical Review Letters, Vol. 63, Issue 21 https://doi.org/10.1103/physrevlett.63.2369	journal	November 1989

Cited By (1)

Effects of collisional ion orbit loss on neoclassical tokamak radial electric fields Zhu, Hongxuan; Stoltzfus-Dueck, T.; Hager, R. Princeton Plasma Physics Laboratory (PPPL), Princeton, NJ (United States) https://doi.org/10.11578/1888260	dataset	January 2022