Wavelet analysis of gyrokinetic turbulence

A method to extract coherent structures out of the data from a gyrokinetic simulation. The data is generated with GS2, which is a nonlinear kinetic code that studies low-frequency turbulence in magnetized plasma. We analyze data from simulations of ion temperature gradient-driven (ITG) turbulence, for a range of physics parameters. The parameters are chosen to produce a strong variation in the amplitude of nonlinearly generated zonal flows. To find coherent structures, the data is projected onto an orthogonal wavelet basis, a nonlinear thresholding is applied to the wavelet coefficients and the denoised data is then reconstructed in physical space.