Collisions in global gyrokinetic particle-in-cell code ORB5

グローバルジャイロ運動論的PICコードORB5における衝突効果

Vernay, T.*; Brunner, S.*; Villard, L.*; Jolliet, S.; McMillan, B. F.*; Lapillonne, X.*

Vernay, T.*; Brunner, S.*; Villard, L.*; Jolliet, S.; McMillan, B. F.*; Lapillonne, X.*

In this work, a Lorentz collision operator using a random walk over the pitch angle, as well as a full, linearized self-collision operator including a random walk in velocity space and a background reaction acting on the weights, are implemented in a simple 1D Particle-In-Cell (PIC) code simulating Langmuir waves with a 2 weights scheme. The crucial conservation properties of the discretized collision operators are explained. In a second step, the implementations of the 2 weights scheme and such operators in the global gyrokinetic PIC code ORB5 are presented. Some results concerning the effects of collisions on micro-instabilities and neoclassical transport are studied.