Density fluctuations in the solar wind : effects of nearly incompressible theory

Previously derived nearly incompressible theory with the inclusion of a simple large-scale inhomogeneous background (static and spherically symmetric) is examined by direct numerical simulations of non-stationary two dimensional turbulence. According to the theory, leading order density fluctuations satisfy a passive scalar evolution equation with additional source term induced by coupling to the large-scale inhomogeneous background. In this poster we investigate the decay rates and spectral shapes of density fluctuations together with implications for solar wind data.