ExB mean flows in finite ion temperature plasmas
  The impact of ion pressure dynamics on E x B mean flows is investigated. Using a simplified, two-dimensional, drift ordered fluid model in the thin-layer approximation, three stresses in addition to the Reynolds stress are shown to modify the E x B mean flow. These additional terms in the stress tensor all require ion pressure fluctuations. Quasi-linear analysis show that these additional stresses are as important as the Reynolds stress, and hence must be taken into account in analysis of transport barriers in which sheared E x B mean flows are key ingredients. 
J. Madsen, J. Juul Rasmussen, V. Naulin, and A. H. Nielsen
physics.plasm-ph