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Author: Scott E. Parker
Requested Type: Poster
Submitted: 2017-03-16 12:32:01

Co-authors: B.J. Sturdevant , Y. Chen, M.T. Miecnikowski

Contact Info:
Dept. of Physics, Univ. of Colorado, Boulder
CB 390
Boulder, CO   80309
USA

Abstract Text:
A simulation model for the toroidal ion temperature gradient (ITG) instability using the Lorentz force, rather than gyrokinetics, is presented. Such a model provides an important validation tool for gyrokinetics in applications where higher order terms may be important. A number of multiple-scale simulation techniques are employed in this work, based on the previous success in slab geometry with an implicit orbit averaged and sub-cycled delta-f model [1]. In toroidal geometry, we have derived a particle integration scheme based on variational principles, which produces stable and accurate ion trajectories on long time scales. Orbit averaging and sub-cycling will be implemented using the variational particle advance. The inclusion of equilibrium gradients in the fully kinetic delta-f formulation is achieved through the use of a guiding center coordinate transformation of the weight equation. Drift terms do not explicitly appear in the Lorentz ion equations, so multiscale approximations made for the drift terms cannot be utilized. We have developed a fully kinetic (6D) global toroidal electrostatic adiabatic electron code. We will report linear results benchmarking with the GEM gyrokinetic code for the Cyclone base case. Nonlinear simulations of the ITG mode in shearless slab geometry show excellent agreement with gyrokinetics. Nonlinearly, Ion Bernstein waves are excited in the full kinetic simulations. Progress on nonlinear toroidal simulations will be discussed.

[1] B.J. Sturdevant, S.E. Parker, Y. Chen, and B. Hause, J. Comput. Phys., 316 519 (2016).

Comments:
Computer Simulation of Plasmas