Title: Implications of advanced collision operators for gyrokinetic simulation

Abstract

In this paper, we explore both the potential improvements and pitfalls that arise when using advanced collision models in gyrokinetic simulations of plasma microinstabilities. Comparisons are made between the simple-but-standard electron Lorentz operator and specific variations of the advanced Sugama operator. The Sugama operator describes multi-species collisions including energy diffusion, momentum and energy conservation terms, and is valid for arbitrary wavelength. We report scans over collision frequency for both low and high $${k}_{\theta }{\rho }_{s}$$ modes, with relevance for multiscale simulations that couple ion and electron scale physics. The influence of the ion–ion collision terms—not retained in the electron Lorentz model—on the damping of zonal flows is also explored. Collision frequency scans for linear and nonlinear simulations of ion-temperature-gradient instabilities including impurity ions are presented. Finally, implications for modeling turbulence in the highly collisional edge are discussed.

Authors:

Belli, E. A. ^[1]; Candy, J. ^[1]

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+ Show Author Affiliations

1. General Atomics, San Diego, CA (United States)

Publication Date:

Thu Feb 23 00:00:00 EST 2017

Research Org.:

General Atomics, San Diego, CA (United States)

Sponsoring Org.:

USDOE

OSTI Identifier:

1466043

Grant/Contract Number:  

FG02-95ER54309

Resource Type:

Accepted Manuscript

Journal Name:

Plasma Physics and Controlled Fusion

Additional Journal Information:

Journal Volume: 59; Journal Issue: 4; Journal ID: ISSN 0741-3335

Publisher:

IOP Science

Country of Publication:

United States

Language:

English

Subject:

70 PLASMA PHYSICS AND FUSION TECHNOLOGY; gyrokinetics; turbulence; collisions; tokamak