A comprehensive gyrokinetic description of global electrostatic microinstabilities in a tokamak
It is believed that low frequency microinstabilities such as ion temperature gradient (ITG) driven modes and trapped electron modes (TEMs) are largely responsible for the experimentally observed anomalous transport via the ion and electron channels in a tokamak. In the present work, a comprehensive global linear gyrokinetic model incorporating fully kinetic (trapped and passing) electrons and ions, actual ion to electron mass ratio, radial coupling, and profile variation is used to investigate the ITG driven modes and pure TEMs. These modes are found to exhibit multiscale structures in the presence of nonadiabatic passing electrons. The multiscale structure is related to the large nonadiabaticity of electrons in the vicinity of mode rational magnetic surfaces and leads to reduced mixing length estimates of transport compared to those obtained from adiabatic electron models.
Keywords: electron traps ; particle traps ; plasma instability ; plasma kinetic theory ; plasma temperature ; plasma toroidal confinement ; plasma transport processes ; Tokamak devices ; Plasma Turbulence ; Comparing Simulation ; Anomalous Transport ; Stabilization ; Equations ; Electrons ; Waves ; Modes
Record created on 2009-12-14, modified on 2016-08-08