Fluid and gyrokinetic turbulence in open field-line, helical plasmas
Abstract
Two-fluid Braginskii codes have simulated open-field line turbulence for over a decade, and only recently, it has become possible to study these systems with continuum gyrokinetic codes. This work presents a first-of-its-kind comparison between fluid and (long-wavelength) gyrokinetic models in open field-lines, using the GDB and Gkeyll codes to simulate interchange turbulence in the Helimak device at the University of Texas [T. N. Bernard et al., Phys. Plasmas 26, 042301 (2019)]. Partial agreement is attained in a number of diagnostic channels when the GDB sources and sheath boundary conditions (BCs) are selected carefully, especially the heat-flux BCs that can drastically alter the temperature. The radial profile of the fluctuation levels is qualitatively similar and quantitatively comparable on the low-field side, although statistics such as moments of the probability density function and the high-frequency spectrum show greater differences. This comparison indicates areas for future improvement in both simulations, such as sheath BCs, and improvements in GDB like particle conservation and spatially varying thermal conductivity, in order to achieve better fluid-gyrokinetic agreement and increase fidelity when simulating experiments.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Aug 01, 2020
- Source ID
- 10.1063/5.0005333
Entities
People
- Ammar Hakim
- B. N. Rogers
- Ben Zhu
- Gregory W. Hammett
- Manaure Francisquez
- Tess Bernard
Organizations
- Air Force Office of Scientific Research
- Dartmouth College
- General Atomics
- Lawrence Livermore National Laboratory
- Massachusetts Institute of Technology
- Princeton Plasma Physics Laboratory
- United States Department of Energy
- University of Texas at Austin