Separating contributions to plasma vorticity in the high-latitude ionosphere from large-scale convection and meso-scale turbulence

Measurements of ionospheric flow vorticity can be used for studying ionospheric plasma transport processes, such as convection and turbulence, over a wide range of spatial scales. Here, we analyse probability density functions (PDFs) of ionospheric vorticity for selected regions of the northern hemisphere high-latitude ionosphere as measured by the Super Dual Auroral Radar Network (SuperDARN) over a six-year interval (2000-2005 inclusive). Subdividing these PDFs for opposite polarities of the By component of the prevailing Interplanetary Magnetic Field (IMF) allows the separation into two distinct components: (1) A single-sided Weibull distribution which relates to the large-scale convection driven by magnetic reconnection; (2) A double-sided and symmetric q-exponential distribution which arises from meso-scale plasma flow related to processes such as turbulence.