Solar Wind Turbulence Cascade in the Ion-Kinetic Regime: Effect of Proton Temperature Anisotropy

Recently, there has been renewed interest in arriving at a better understanding of the transition to kinetic scales in the solar wind turbulent cascade. We have started using 2-D hybrid simulations (kinetic ions, electron fluid) to quantify the spectrum in the ion-kinetic regime, concentrating on protons. Due to the large-scale structure and evolution of the solar wind, observed proton distributions typically are not isotropic, but instead cover the entire range between marginally unstable conditions of parallel and perpendicular temperature anisotropy. Here, we analyze the simulation wave spectra to determine the characteristic dependence on anisotropy. We also discuss the derived observable spectrum as seen by a spacecraft in the solar wind as a function of magnetic field orientation