Nonlinear aspects of inhomogeneous solar wind plasma

We have developed two dimensional, time dependent, nonlinear fluid simulations of freely expanding solar wind plasma. In our computational model, the small scale solar wind fluctuations are modeled in the presence of large scale background inhomogeneous flows. The background inhomogeneous flows are treated statically, whereas the fluctuations evolve according to MHD turbulence. We find that the large scale inhomogeneity introduces intrinsic compressibility in the evolution of characteristic turbulent fluctuations. Consequently, turbulence is dominated by compressible modes over the Aflvenic fluctuations. Energy cascades are slowed down by the inhomogeneous flows which further lead to the flattening of the turbulent spectra from the usual Kolmogorov-like 5/3 law. Finally, the large scale flows tend to introduce significant deviation from Guassianiaty in the nature of anisotropic and inhomogeneous solar wind MHD turbulence.