FINITE-ELEMENT APPROACH TO GLOBAL GYROKINETIC PARTICLE-IN-CELL SIMULATIONS USING MAGNETIC COORDINATES

We present a fully-global linear gyrokinetic simulation code (GYGLES) aimed at describing the unstable spectrum of the ion-temperature-gradi ent modes in toroidal geometry. We formulate the Particle-In-Cell meth od with finite elements defined in magnetic coordinates, which provide s excellent numerical convergence properties. The poloidal mode struct ure corresponding to k(parallel to) = 0 is extracted without approxima tion from the equations, which reduces drastically the numerical resol ution needed. The code can simulate routinely modes with both very lon g and very short toroidal wavelengths, can treat realistic (MHD) equil ibria of any size, and runs on a massively parallel computer. (C) 1998 Elsevier Science B.V.