Abstract Details
Abstracts
Author: Benjamin J Sturdevant
Requested Type: Pre-Selected Invited
Submitted: 2017-03-10 12:42:06
Co-authors: S.E.Parker,Y.Chen,M.Miecnikowski
Contact Info:
University of Colorado at Boulder
UCB 390
Boulder, Colorado 80309
United States
Abstract Text:
We report the development of a simulation model with fully kinetic, Lorentz force dynamics using implicit multi-scale techniques [1]. Delta-f particle simulations with fully kinetic ions are now capable of accurately capturing low-frequency physics, including the finite Larmor radius (FLR) effects in drift wave-type instabilities, which is more typically the domain of gyrokinetics. Such a model allows for verification of gyrokinetics in situations where the smallness of the ordering parameters is under question. Additionally, fully kinetic simulation can help identify the relative importance of higher order terms in gyrokinetic theory. Here we present fully kinetic simulations of the ion-temperature-gradient (ITG) instability. An orbit averaging and sub-cycling scheme is utilized as well as an implicit particle time advance based on variational principles. We will report results comparing the fully kinetic model with gyrokinetics. In slab geometry, excellent agreement is obtained linearly and nonlinearly including full FLR effects. High-frequency Ion Bernstein waves, which are present in the fully kinetic model, can easily be suppressed with the implicit time advance. A toroidal model is now fully operational, using orthogonal coordinates for the particle advance, but field-line-following coordinates for the field solve [2]. This allows high resolution of the field-aligned mode structure. Simulation results in three-dimensional toroidal geometry show good agreement with gyrokinetic simulation.
[1] B.J. Sturdevant, S.E. Parker, Y. Chen, and B. Hause, J. Comput.Phys., 316 519 (2016).
[2] B.J. Sturdevant, S.E. Parker, and Y. Chen, “Low-Frequency Fully Kinetic Simulation of the Toroidal ITG Instability”, to appear in Phys. Plasmas (2017).
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