Development of a new zonal flow equation solver by diagonalisation and its application in non-circular cross-section tokamak plasmas

Study of Plasma Shaping Effects on ITG Instability Using Global Gyrokinetic Code GKNET with Analytical Magnetic Equilibrium

“…By means of the rectangular (R, Z, ζ) version of our global gyrokinetic code GKNET [7,8], which uses a new real space field solver based on the diagonalization of zonal flow equation, we investigated plasma shaping effects on the collisionless damping of GAM. We found that not only elongation but also triangularity is effective in increasing the damping rate of GAM regardless of the sign, either plus or minus [9]. In this case, we employed the Miller equilibrium [10].…”

Global gyrokinetic simulation of turbulence driven by kinetic ballooning mode

“…We describe our new global electromagnetic simulation code, which is developed by extending GKNET, 19,20 in this section. We divide a distribution function into the Maxwellian and perturbed parts, 2 ?…”

“…(1)- 3, is solved by extending a version of GKNET. 19,20 We use the toroidal coordinates (r, h, u) in the configuration space and ðv k ; lÞ in the velocity space. In our numerical simulation code, the time integration is made by the fourth-order Runge-Kutta method.…”

“…In this paper, we investigate the saturation of KBM by means of a new global electromagnetic gyrokinetic simulation code developed by extending a version of GKNET. 19,20 Our simulations include nonlinear mode coupling among unstable toroidal modes and stable low toroidal modes. The original GKNET is the electrostatic full-f gyrokinetic code with the polar 19 or rectangular 20 coordinates in the poloidal plane.…”

“…19,20 Our simulations include nonlinear mode coupling among unstable toroidal modes and stable low toroidal modes. The original GKNET is the electrostatic full-f gyrokinetic code with the polar 19 or rectangular 20 coordinates in the poloidal plane. This code enables us to investigate global turbulent transport and resultant background profile formation coupled with radial mean flow shear such as the staircase 21 and internal transport barrier triggered by momentum injection.…”