A Multiscale Method - Equation Free Projective Integration Applied to Global Gyrokinetic Particle Simulations of Plasma Turbulence

Abstract

A multiscale method called Equation Free Proj ective Integration (EFPI) is being applied to global gyrokinetic particle simulation of plasma turbulence, which provides a framework for studying a variety of multiscale problems in plasma physics. In our EFPI simulations, Ion-Temperature Gradient (ITG) driven transport is modeled on two scales: a microscale related to the ITG turbulence and a macroscale related to the slow-varying source term. The long timescale turbulence behavior of the system is determined by extrapolating forward in time using estimates of the macroscales obtained from short duration simulations of the microscale dynamics. In our EFPI simulations, the heat flux of the turbulence will slowly vary by way of a time varying source. We will compare directly to turbulence simulations without EFPI. The demonstration of EFPI for turbulence simulation may have impact on other multiscale problems. For example, the nonlinear interaction of different modes at different space-time scales, which is topical problem in plasma physics.