Energetic particle optimization of quasi-axisymmetric stellarator equilibria

LeViness, Alexandra; Schmitt, John C.; Lazerson, Samuel A.; Bader, Aaron; Faber, Benjamin J.; Hammond, Kenneth C.; Gates, David A.

doi:10.1088/1741-4326/aca4e3

Energetic particle optimization of quasi-axisymmetric stellarator equilibria

Journal Article · Sun Dec 11 23:00:00 EST 2022 · Nuclear Fusion

DOI:https://doi.org/10.1088/1741-4326/aca4e3· OSTI ID:1903396

; ; ; ; ; ;

Abstract

An important goal of stellarator optimization is to achieve good confinement of energetic particles such as, in the case of a reactor, alphas created by deuterium–tritium fusion. In this work, a fixed-boundary stellarator equilibrium was re-optimized for energetic particle confinement via a two-step process: first, by minimizing deviations from quasi-axisymmetry (QA) on a single flux surface near the mid-radius, and secondly by maintaining this improved QA while minimizing the analytical quantity $Γ_{C}$ , which represents the angle between magnetic flux surfaces and contours of $J_{| |}$ , the second adiabatic invariant. This was performed multiple times, resulting in a group of equilibria with significantly reduced energetic particle losses, as evaluated by Monte Carlo simulations of alpha particles in scaled-up versions of the equilibria. This is the first time that energetic particle losses in a QA stellarator have successfully been reduced by optimizing $Γ_{C}$ . The relationship between energetic particle losses and metrics such as QA error ( $E_{q a}$ ) and $Γ_{C}$ in this set of equilibria were examined via statistical methods and a nearly linear relationship between volume-averaged $Γ_{C}$ and prompt particle losses was found.

View Journal Article

Sponsoring Organization:: USDOE

Grant/Contract Number:: AC02-09CH11466

OSTI ID:: 1903396

Alternate ID(s):: OSTI ID: 1899395
OSTI ID: 1905774

Journal Information:: Nuclear Fusion, Journal Name: Nuclear Fusion Journal Issue: 1 Vol. 63; ISSN 0029-5515

Publisher:: IOP PublishingCopyright Statement

Country of Publication:: IAEA

Language:: English

References (30)

Stellarator symmetry Dewar, R. L.; Hudson, S. R. Physica D: Nonlinear Phenomena, Vol. 112, Issue 1-2 https://doi.org/10.1016/S0167-2789(97)00216-9	journal	January 1998
Design of the national compact stellarator experiment (NCSX) Nelson, B. E.; Berry, L. A.; Brooks, A. B. Fusion Engineering and Design, Vol. 66-68 https://doi.org/10.1016/S0920-3796(03)00183-2	journal	September 2003
Quasi-axisymmetric magnetic fields: weakly non-axisymmetric case in a vacuum Plunk, G. G.; Helander, Per Journal of Plasma Physics, Vol. 84, Issue 2 https://doi.org/10.1017/S0022377818000259	journal	April 2018
Stellarator equilibria with reactor relevant energetic particle losses Bader, Aaron; Drevlak, M.; Anderson, D. T. Journal of Plasma Physics, Vol. 85, Issue 5 https://doi.org/10.1017/S0022377819000680	journal	October 2019
Neoclassical diffusion in an l = 3 stellarator Connor, J. W. Physics of Fluids, Vol. 17, Issue 1 https://doi.org/10.1063/1.1694573	journal	January 1974
Improving confinement in quasi-axisymmetric stellarators Mynick, H. E.; Boozer, A. H.; Ku, L. P. Physics of Plasmas, Vol. 13, Issue 6 https://doi.org/10.1063/1.2213960	journal	June 2006
Poloidal motion of trapped particle orbits in real-space coordinates Nemov, V. V.; Kasilov, S. V.; Kernbichler, W. Physics of Plasmas, Vol. 15, Issue 5 https://doi.org/10.1063/1.2912456	journal	May 2008
Comparison of particle trajectories and collision operators for collisional transport in nonaxisymmetric plasmas Landreman, M.; Smith, H. M.; Mollén, A. Physics of Plasmas, Vol. 21, Issue 4 https://doi.org/10.1063/1.4870077	journal	April 2014
Existence of quasihelically symmetric stellarators Garren, D. A.; Boozer, A. H. Physics of Fluids B: Plasma Physics, Vol. 3, Issue 10 https://doi.org/10.1063/1.859916	journal	October 1991
Plasma equilibrium with rational magnetic surfaces Boozer, Allen H. Physics of Fluids, Vol. 24, Issue 11 https://doi.org/10.1063/1.863297	journal	January 1981
Steepest-descent moment method for three-dimensional magnetohydrodynamic equilibria Hirshman, S. P. Physics of Fluids, Vol. 26, Issue 12 https://doi.org/10.1063/1.864116	journal	January 1983
Stellarators with the magnetic symmetry of a tokamak Garabedian, P. R. Physics of Plasmas, Vol. 3, Issue 7 https://doi.org/10.1063/1.871965	journal	July 1996
Initial physics achievements of large helical device experiments Motojima, O.; Yamada, H.; Komori, A. Physics of Plasmas, Vol. 6, Issue 5 https://doi.org/10.1063/1.873443	journal	May 1999
Evaluation of 1/ν neoclassical transport in stellarators Nemov, V. V.; Kasilov, S. V.; Kernbichler, W. Physics of Plasmas, Vol. 6, Issue 12 https://doi.org/10.1063/1.873749	journal	December 1999
Optimization of quasi-symmetric stellarators with self-consistent bootstrap current and energetic particle confinement Landreman, M.; Buller, S.; Drevlak, M. Physics of Plasmas, Vol. 29, Issue 8 https://doi.org/10.1063/5.0098166	journal	August 2022
Quasi-axially symmetric stellarators Garabedian, P. R. Proceedings of the National Academy of Sciences, Vol. 95, Issue 17 https://doi.org/10.1073/pnas.95.17.9732	journal	August 1998
Considerations on energy confinement time scalings using present tokamak databases and prediction for ITER size experiments Sauter, O.; Martin, Y. Nuclear Fusion, Vol. 40, Issue 5 https://doi.org/10.1088/0029-5515/40/5/308	journal	May 2000
Fast particle confinement with optimized coil currents in the W7-X stellarator Drevlak, M.; Geiger, J.; Helander, P. Nuclear Fusion, Vol. 54, Issue 7 https://doi.org/10.1088/0029-5515/54/7/073002	journal	April 2014
BEAMS3D Neutral Beam Injection Model McMillan, Matthew; Lazerson, Samuel A. Plasma Physics and Controlled Fusion, Vol. 56, Issue 9 https://doi.org/10.1088/0741-3335/56/9/095019	journal	July 2014
Improving fast-particle confinement in quasi-axisymmetric stellarator optimization Henneberg, S. A.; Drevlak, M.; Helander, P. Plasma Physics and Controlled Fusion, Vol. 62, Issue 1 https://doi.org/10.1088/1361-6587/ab5add	journal	December 2019
Simulating fusion alpha heating in a stellarator reactor Lazerson, Samuel A.; LeViness, Alexandra; Lion, Jorrit Plasma Physics and Controlled Fusion, Vol. 63, Issue 12 https://doi.org/10.1088/1361-6587/ac35ee	journal	November 2021
Properties of a new quasi-axisymmetric configuration Henneberg, S. A.; Drevlak, M.; Nührenberg, C. Nuclear Fusion, Vol. 59, Issue 2 https://doi.org/10.1088/1741-4326/aaf604	journal	January 2019
Validation of the BEAMS3D neutral beam deposition model on Wendelstein 7-X Lazerson, Samuel A.; Ford, Oliver P.; Nuehrenberg, Carolin Nuclear Fusion, Vol. 60, Issue 7 https://doi.org/10.1088/1741-4326/ab8e61	journal	June 2020
Modeling and measurement of energetic particle slowing down in Wendelstein 7-X Lazerson, Samuel A.; Pfefferlé, David; Drevlak, Michael Nuclear Fusion, Vol. 61, Issue 9 https://doi.org/10.1088/1741-4326/ac0771	journal	July 2021
Modeling of energetic particle transport in optimized stellarators Bader, A.; Anderson, D. T.; Drevlak, M. Nuclear Fusion, Vol. 61, Issue 11 https://doi.org/10.1088/1741-4326/ac2991	journal	October 2021
A model for the fast evaluation of prompt losses of energetic ions in stellarators Velasco, J. L.; Calvo, I.; Mulas, S. Nuclear Fusion, Vol. 61, Issue 11 https://doi.org/10.1088/1741-4326/ac2994	journal	October 2021
Energetic particle loss mechanisms in reactor-scale equilibria close to quasisymmetry Paul, E. J.; Bhattacharjee, A.; Landreman, M. Nuclear Fusion, Vol. 62, Issue 12 https://doi.org/10.1088/1741-4326/ac9b07	journal	November 2022
Magnetic Fields with Precise Quasisymmetry for Plasma Confinement Landreman, Matt; Paul, Elizabeth Physical Review Letters, Vol. 128, Issue 3 https://doi.org/10.1103/PhysRevLett.128.035001	journal	January 2022
Plasma Diffusion in a Toroidal Stellarator Galeev, A. A.; Sagdeev, R. Z.; Furth, H. P. Physical Review Letters, Vol. 22, Issue 11 https://doi.org/10.1103/PhysRevLett.22.511	journal	March 1969
The ARIES-CS Compact Stellarator Fusion Power Plant Najmabadi, F.; Raffray, A. R.; Abdel-Khalik, S. I. Fusion Science and Technology, Vol. 54, Issue 3 https://doi.org/10.13182/FST54-655	journal	October 2008

Similar Records

Deciphering the sensitivity of urban canopy air temperature to anthropogenic heat flux with a forcing-feedback framework

Journal Article · Mon Aug 14 00:00:00 EDT 2023 · Environmental Research Letters · OSTI ID:1995029

The constraint of plasma power balance on runaway avoidance

Journal Article · Mon Jan 16 23:00:00 EST 2023 · Nuclear Fusion · OSTI ID:1910296

Validation of 2D Te and ne measurements made with Helium imaging spectroscopy in the volume of the TCV divertor

Journal Article · Thu Feb 09 23:00:00 EST 2023 · Nuclear Fusion · OSTI ID:1924378

Energetic particle optimization of quasi-axisymmetric stellarator equilibria

Citation Formats

References (30)

Similar Records

Related Subjects