Numerical considerations for simulating the H-mode physics using gyrokinetic codes*

As shown in a recent paper on the pedestal physics [1], the L-H transition requires the knowledge of the force balance among the electric field, the pressure gradient and the V x B motion.  As such, we need to use the fully electromagnetic gyrokinetic formulation including the physics related to the vector potentials A_\parallel and A_\perp [2] . In addition, the formation of the radial electric field well at the pedestal, which is the signature of the H-mode, requires the finite Larmor radius effects in the region with sharp pressure gradients [3]. It is believed that gyrokinetic codes, such as the GTC code [4,5] at UC-Irvine, with some minor modifications would be the best tool for the investigation of the H-mode physics and the related issues.

[1] W. W. Lee and R. B. White, Phys. Plasmas 26, 040701 (2019)

[2] W. W. Lee, Phys. Plasmas 23, 070705 (2016)

[3] W. W. Lee and R. B. White, Phys. Plasmas 24, 081204 (2017)

[4] J. Bao, D. Liu, and Z. Lin, Phys. Plasmas 24, 102516 (2017)

[5] J. Bao, Z. Lin and Z. X. Lu, Phys. Plasmas 25, 022515 (2018)