Numerical Model Developments of A New Code (ANC) for Fully-kinetic Ion Simulation of Turbulence in C-2W

A principal objective of C-2W, the latest device at TAE Technologies, Inc. is to better characterize turbulence-driven particle and energy transport in beam-driven field-reversed configuration (FRC) plasmas. Doppler Backscattering (DBS) measurements on C-2U, the predecessor to C-2W, show the absence of low toroidal wavenumber turbulent fluctuations in the FRC core^[1]. Gyrokinetic simulations agree qualitatively, and demonstrate stabilization of these core fluctuations via several mechanisms including large ion Larmor radius, negative radial magnetic field gradient, and short field-line connection length effects^[2].

Upgrades to the diagnostic suite of C-2W, including an expanded Far-Infrared Interferometer system and a planned combination DBS and Cross-Polarization Scattering diagnostic, along with refinements to the turbulence code, A New Code (ANC), will enable detailed experiment-simulation cross-validation. In this work, model developments to ANC’s fully-kinetic ion scheme, including a field aligned mesh and a flux-based density advance are presented with benchmarks. Plans and early progress of validation efforts with C-2W experimental data will also be discussed.

^[1] L. Schmitz et al, Nat. Commun. 7, 13860 (2016).

^[2] C. K. Lau et al, Phys. Plasmas, 24, 082512 (2017).