Authors: Hui Li (LANL) and KaHo Yuen (LANL)

Recent theoretical and numerical studies of the compressible MHD turbulence have revealed new properties in describing the temporal function of MHD turbulence. Such temporal behavior has interesting implications for understanding the transport of energetic particles as they move through the turbulent solar wind plasma. Specifically, we find that the frequency power spectrum of the compressible MHD turbulence follows a Lorentzian-like shape that is asymmetric around the eigen-frequencies. In addition, as a function of the strength of turbulent Mach number, there are quantifiable broadening properties around the wave eigen-frequencies for different waves. These results are verified by both analytic theoretical derivation and numerical simulations. Using these new frequency power spectra, we calculate the expected transport coefficients (such as pitch angle and energy exchanges) of energetic particles in the solar wind turbulence background. We find that the mean free path of these energetic particles can be altered significantly, and we further quantify their properties as a function of particle energy and the turbulence properties. Implications for understanding the solar energetic particle observations and low energy cosmic rays will be discussed.