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

Abstract

Fusion plasmas are believed to be nearly adiabatic where the electrostatic potential I center dot 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 beta and the phase difference delta between I center dot and n in Fourier space. The dynamics of I center dot and n can be approximated in two-dimensional resistive-drift turbulence by using the Hasegawa-Wakatani model. Steady-state expressions are found for both beta and delta when the spatial scale is larger than rho s. While the E x B nonlinear flux plays a crucial role in the determination of delta, it is of higher order and negligible in the case of beta, which is almost unity. The fluctuations of large scale compared to rho s are closer to be adiabatic, and delta is found to be small, but finite, around the meso scale rho s that may increase the transport.