Authors: W. Gorman (University of Arizona), K. G. Klein (University of Arizona)

Quantifying how energy is partitioned by the dissipation of turbulent plasmas is necessary for characterizing the thermodynamics of a wide variety of systems. Howes et al. 2008 developed a model for a MHD turbulent cascade that uses assumptions of local nonlinear energy transfer and critical balance between the linear propagation and nonlinear interaction times to construct a steady-state cascade of energy from inertial through dissipation scales where Landau damping onto ions and then electrons terminates the cascade. This model is widely used to quantify expectations for the bifurcation of energy between ions and electrons in solar system and astrophysical plasmas. The linear solutions for low-frequency kinetic Alfven waves have a noticeable gap where the frequency drops to zero near the proton gyroscale for a critical value of proton plasma beta greater than approximately 30; This gap increases in width for increasing values of the plasma beta. Assuming only local nonlinear energy transfer (no possibility for large eddies to shear apart smaller ones or for smaller eddies to diffuse across larger ones) the energy cascade should halt once it reaches the gap (because there can be no wave propagation through the region). In this study, we investigate and update the 2008 cascade model, which showed the cascade proceeding continuously through this gap region, as well as an updated Weakened Cascade model by Howes et al. 2011 that allows for non-local contributions to the cascade by including effects of shearing and diffusion, to properly physically model nonlinear energy transfer across the high-beta, zero-frequency gap. This update will be relevant for a variety of heliospheric and astrophysical systems where the thermal pressure dominates over the magnetic pressure.