Verification of fractional quasilinear renormalization theory using drift-wave turbulence simulations

A very recent renormalization scheme for turbulent transport has been formulated in terms fractional differential operators [1]. In this contribution, we test it against numerous tracer particle transport experiments carried out in simulations of drift-wave turbulence in slab geometry [2]. The simplified geometry allows that simulations be carried out for a sufficiently large number of decorrelation times so that the long-term dynamics captured by these operators can be made apparent. By changing the relative dominance of the polarization and ${\rm\bf E}\times{\rm\bf B}$ nolinearities artificially, we tune at will the degree of homogeneity and isotropy of the system. Additionally, externally-driven sheared flows can also be considered. This wide spectrum of options creates a superb environment to test the strengths and weaknesses of the fractional renormalization formalism. With it, the potential for application to more realistic geometries such as those in state-of-the-art tokamak turbulence codes will be assessed.\\ \noindent{\bf References}\\ {\small \noindent [1] {R. S\'anchez, B.A. Carreras, D.E. Newman, V. Lynch and B.Ph. van Milligen, submitted (2005)\\} \noindent [2] {D.E. Newman, P.W. Terry, P.H. Diamond and Y. Liang, Phys. Fluids B \textbf{5}, 1140 (1993) } }