Statistical analysis of resistive drift wave turbulence
Paper in proceeding, 2017
Resistive drift wave turbulence is a multipurpose paradigm that can be used to understand transport
at the edge of fusion devices. The Hasegawa-Wakatani model captures the essential physics of drift
turbulence while retaining the simplicity needed to gain a qualitative understanding of this process.
We provide a theoretical interpretation of numerically generated probability density functions (PDFs)
of intermittent events in Hasegawa-Wakatani turbulence with enforced equipartition of energy in
large scale zonal flows and small scale drift turbulence. We find that for a wide range of adiabatic
index values the stochastic component representing the small scale turbulent eddies of the flow,
obtained from the ARIMA model, exhibits super-diffusive statistics, consistent with intermittent
transport. The PDFs of large events (above one standard deviation) are well approximated by the
Laplace distribution, while small events often exhibit a Gaussian character. Furthermore there exist
a strong influence of zonal flows for example, via shearing and then viscous dissipation maintaining
a sub-diffusive character of the fluxes.