Cross phase of resistive-drift plasma turbulence near an adiabatic state

Abstract

Fusion plasmas are believed to be nearly adiabatic where the electrostatic potential ϕ and the plasma density n are equal under a proper normalization. The degree of the plasma status off such a state can be quantified by using the magnitude ratio β and the phase difference δ between ϕ and n in Fourier space. The dynamics of ϕ and n can be approximated in two-dimensional resistive-drift turbulence by using the Hasegawa-Wakatani model. Steady-state expressions are found for both β and δ when the spatial scale is larger than ρs. While the E × B nonlinear flux plays a crucial role in the determination of δ, it is of higher order and negligible in the case of β, which is almost unity. The fluctuations of large scale compared to ρs are closer to be adiabatic, and δ is found to be small, but finite, around the meso scale ρs that may increase the transport.