Characteristics of monotonic sheaths near a wall with grazing magnetic incidence

We consider a magnetised plasma in contact with an absorbing planar wall, where the angle between the magnetic field and the wall is small, α<<1 (in radians), and the plasma is uniform in the directions tangential to the wall. The finite ratio of the characteristic electron gyroradius ρe to the Debye length λD, ρe/λD, is retained via a grazing-incidence (α<<1) gyrokinetic treatment (Geraldini 2017 Plasma Phys. Control. Fusion 59 025015; Geraldini 2018 Plasma Phys. Control. Fusion 60 125002) Building on a previously developed iterative scheme (Geraldini 2018 Plasma Phys. Control. Fusion 60 125002; Ewart 2021 Plasma Phys. Control. Fusion 64 015010) to solve for the steady-state electrostatic potential in the quasineutral magnetic presheath of width ∼ρS, we developed a scheme that simultaneously solves for both the presheath and the positively charged Debye sheath of width λD in the limit λD/ρS—>0, provided that the electrostatic potential solution is monotonic. The code, called GYRAZE, thus provides the energy-angle distribution of ions at the wall and the velocity distributions of electrons reflected by the wall for different values of wall potential.