Relationship between the H-mode in tokamaks and the finite-Larmor-radius (FLR) modified Beltrami/Taylor state

ORAL

Abstract

It has been shown that the radial electric field at the H-mode pedestal is the result of charge separation between the ions and electrons due to the FLR effects in the presence of a sharp pressure gradient [1]. The resulting radial electric field, which compares well with many of the experiments as shown in Ref. [1], then gives rise to the ${\bf E} \times {\bf B}$ drift for both the electrons and the ions. Again, because of the FLR effects, it results in a net current in the poloidal direction, which modifies the gyrokinetic vorticity equation [2]. In the Beltrami/Taylor state [3], this current vanishes and the resulting gyrokinetic MHD equations [4] resemble those of Strauss [5], which are MHD stable for $q > 1$. Details will be presented.
[1] W. W. Lee and R. B. White, Phys. Plasmas {\bf 24}, 081204 (2017);
[2] W. W. Lee, Phys. Plasmas {\bf 23}, 070705 (2016);
[3] Z. Yoshida, S. M. Mahajan, S. Ohsaki, M. Iqbal and N. Shatashivili, Phys. Plasmas {\bf 8}, 2125 (2001).
[4] W. W. Lee, S. R. Hudson and C. H. Ma, Phys. Plasmas {\bf 24}, 124508 (2017);
[5] H. R. Strauss, Phys. Fluids {\bf 19}, 134 (1976).

Presenters

  • Wei-li W Lee

    Princeton Plasma Phys Lab

Authors

  • Wei-li W Lee

    Princeton Plasma Phys Lab

  • Roscoe B White

    Princeton Plasma Phys Lab