Magneto-Fluid Dynamics Seminar

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A flux balanced Hasegawa-Wakatani model for collisional plasma edge turbulence

Speaker: Di Qi, Courant Institute of Mathematical Sciences

Location: Warren Weaver Hall 905

Date: Tuesday, February 26, 2019, 11 a.m.

Synopsis:

We propose a new reduced fluid model for the study of the drift wave–zonal flow dynamics in
magnetically confined plasmas. Our model can be viewed as an extension of the classic Hasegawa-
Wakatani (HW) model and is based on an improved treatment of the electron dynamics parallel to
the field lines, to guarantee a balanced electron flux on the magnetic surfaces. Our flux-balanced
HW (bHW) model contains the same drift-wave instability as previous HW models, but also has unique features which distinguish it from these models: 1) it converges exactly to the modified Hasegawa-Mima model in the collisionless limit; 2) zonal structures are always present in the flux-balanced model, even for high resistivity, and strongly reduce the level of particle and vorticity flux; 3) the more robust zonal jets also have a higher variability, which is further enhanced when the computational domain is chosen to be elongated in the radial direction.
When the computational domain is elongated in the radial direction, we furthermore observe complex multi-scale dynamics, with multiple jets interacting with one another, and intermittent bursts.