Numerical simulation of ion temperature gradient driven modes in the presence of ion-ion collisions
Abstract
Ion temperature gradient driven modes in the presence of ion-ion collisions in a toroidal geometry with trapped ions were studied by using a 1 2/2 d linearized gyro-kinetic particle simulation code in the electrostatic limit. The purpose is to try to understand the physics of flat density discharges, in order to test the marginal stability hypothesis. Results giving threshold conditions of L sub Ti/R sub 0, an upper bound on k sub chi, and linear growth rates and mode frequencies over all wavelengths for the collisionless ion temperature gradient driven modes are obtained. The behavior of ion temperature gradient driven instabilities in the transition from slab to toroidal geometry, with trapped ions, is shown. A Monte Carlo scheme for the inclusion of ion-ion collisions, in which ions can undergo Coulomb collisional dynamical friction, velocity space diffusion and random walk of guiding centers, was constructed. The effects of ion-ion collisions on the long wave length limit of the ion modes is discussed.
- Publication:
-
Unknown
- Pub Date:
- August 1990
- Bibcode:
- 1990nsit.rept.....X
- Keywords:
-
- Ion Temperature;
- Ionic Collisions;
- Magnetohydrodynamic Stability;
- Monte Carlo Method;
- Plasma Equilibrium;
- Temperature Gradients;
- Boltzmann-Vlasov Equation;
- Distribution Functions;
- Fokker-Planck Equation;
- Tokamak Devices;
- Toroidal Plasmas;
- Wave Dispersion;
- Plasma Physics