The impact of diamagnetic drifts on non-diffusive turbulent transport dynamics

In the past decade or two much progress has been made toward understanding the fundamental dynamics of turbulent transport in general and in the presence of sheared flows. Many of the insights have come from following Lagrangian trajectories using both gyrokinetic simulations of ITG turbulence[1] and simple slab fluid models of drift-wave turbulence[2]. In this work, using the same tools, the impact of simple diamagnetic drifts on the dynamics of the transport is investigated using numerical simulations of 2D-turbulence in slab geometry with the BETA code. By itself, a diamagnetic drift velocity can have a significant an impact on the transport dynamics both with the drift direction and across the drift direction. These changes can lead to both sub-diffusive and super-diffusive transport. However when coupled with a sheared flow additional dynamics are observed which could lead to interesting profile control tools if one can separately control the two. These new dynamics are in part the result of coherent structure formation localized to particular regions of the flows. The transport dynamics and possible uses will be discussed.

[1] R. Sanchez, D.E. Newman, J.N. Leboeuf, V.K. Decyk and B.A. Carreras, Physical Review Letters 101, 205002 (2008)

[2] D.E. Newman, D. Samaddar, R. Sanchez and B.A. Carreras, in Proc. of the 35th EPS Conference on Plasma Physics, Hersonissos, 9-13 June 2008, ECA Vol. 32, p. 1.044 (2008)