Statistical analysis of vortex formation in 2D zonal flows
GJJ Botha
Northumbria University
J Anderson (Chalmers University, Sweden)
The thin width of the solar tachocline allows for it to be modelled as a two-dimensional plane. By considering local turbulence, one can use Cartesian coordinates in the beta-plane approximation of geophysics, or equivalently, the drift wave approximation of fusion plasmas. The turbulence features a dual cascade formed by the energy and enstrophy, resulting in vortex formation. A numerical study of this 2D system generated probability density functions (PDFs) that were matched to analytical predictions of PDFs based on the instanton method by removing autocorrelations from the time series of the electrostatic and . The statistics obtained from the system relaxes to Gaussian distributions, except in areas of strong nonlinear interactions where the PDFs are exponentially distributed.