Verification of continuum drift kinetic equation solvers in NIMROD

Journal Article · Sun Mar 15 00:00:00 EDT 2015 · Physics of Plasmas

DOI:https://doi.org/10.1063/1.4914165· OSTI ID:22408212

Held, E. D.; Ji, J. -Y. ^[1]; Kruger, S. E. ^[2]; Belli, E. A. ^[3]; Lyons, B. C. ^[4]

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1. Utah State University, Logan, Utah 84322-4415 (United States)
2. Tech-X Corporation, Boulder, Colorado 80303 (United States)
3. General Atomics, San Diego, California 92186-5608 (United States)
4. Program in Plasma Physics, Princeton University, Princeton, New Jersey 08543-0451 (United States)

Verification of continuum solutions to the electron and ion drift kinetic equations (DKEs) in NIMROD [C. R. Sovinec et al., J. Comp. Phys. 195, 355 (2004)] is demonstrated through comparison with several neoclassical transport codes, most notably NEO [E. A. Belli and J. Candy, Plasma Phys. Controlled Fusion 54, 015015 (2012)]. The DKE solutions use NIMROD's spatial representation, 2D finite-elements in the poloidal plane and a 1D Fourier expansion in toroidal angle. For 2D velocity space, a novel 1D expansion in finite elements is applied for the pitch angle dependence and a collocation grid is used for the normalized speed coordinate. The full, linearized Coulomb collision operator is kept and shown to be important for obtaining quantitative results. Bootstrap currents, parallel ion flows, and radial particle and heat fluxes show quantitative agreement between NIMROD and NEO for a variety of tokamak equilibria. In addition, velocity space distribution function contours for ions and electrons show nearly identical detailed structure and agree quantitatively. A Θ-centered, implicit time discretization and a block-preconditioned, iterative linear algebra solver provide efficient electron and ion DKE solutions that ultimately will be used to obtain closures for NIMROD's evolving fluid model.

• OSTI ID: 22408212
• Journal Information: Physics of Plasmas, Vol. 22, Issue 3; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 1070-664X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
97 MATHEMATICAL METHODS AND COMPUTING
ALGEBRA
BOOTSTRAP CURRENT
COLLISIONS
COULOMB FIELD
DISTRIBUTION FUNCTIONS
ELECTRONS
FINITE ELEMENT METHOD
FOURIER ANALYSIS
HEAT FLUX
INCLINATION
IONS
ITERATIVE METHODS
KINETIC EQUATIONS
NEOCLASSICAL TRANSPORT THEORY
NIMROD
ONE-DIMENSIONAL CALCULATIONS
TOKAMAK DEVICES
VELOCITY
VERIFICATION