Plasma Physics Seminar (Phys 769)

Dr. Gabriel Plunk, IREAP

The Dual Cascade in Gyrokinetic Phase-Space Turbulence

Abstract: Recent theoretical and numerical progress has demonstrated the existence of a dual cascade in two-dimensional gyrokinetic turbulence. This novel turbulence cascade occurs at scales much smaller than the ion larmor radius, and is centered around the process of nonlinear phase-mixing. I will discuss how nonlinear phase-mixing is a critical component to dual cascade. It is then shown how two dimensional gyrokinetics is related to two dimensional fluid theories such as Charney-Hasegawa-Mima turbulence and 2D Navier-Stokes turbulence. Next I will give present the phenomenological theory. Lastly I will outline the theoretical framework for capturing turbulent structures in phase space (two position-space dimensions and one velocity-space dimension) and give a preview of some numerical tests of this theory by Tomo Tatsuno.



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