Statistical features of drift wave plasma turbulence
Paper in proceedings, 2011
During recent years an overwhelming body of evidence show that the overall transport of heat and particles is to a large part caused by intermittency (or bursty events) related to coherent structures. A crucial question in plasma confinement is thus the prediction of the probability distribution functions (PDFs) of the transport due to these structures and of their formation. This work provides a theoretical interpretation of numerically generated probability density functions (PDFs) of intermittent plasma transport events as well as offering an explanation for exponential PDF tails of momentum flux found in recent experiments at CSDX at USCD. Specifically, nonlinear gyrokinetic simulations of ion-temperature-gradient turbulence produce the time
series of heat flux that manifestly exhibit non-Gaussian PDFs with enhanced tails. The result points to a universality in the modeling of intermittent stochastic process while the analytical theory offers predictive capability.