  A specific set of dimensionless plasma and turbulence parameters is
introduced to characterize the nature of turbulence and its dissipation in
weakly collisional space and astrophysical plasmas. Key considerations are
discussed for the development of predictive models of the turbulent plasma
heating that characterize the partitioning of dissipated turbulent energy
between the ion and electron species and between the perpendicular and parallel
degrees of freedom for each species. Identifying the kinetic physical
mechanisms that govern the damping of the turbulent fluctuations is a critical
first step in constructing such turbulent heating models. A set of ten general
plasma and turbulence parameters are defined, and reasonable approximations
along with the exploitation of existing scaling theories for
magnetohydrodynamic turbulence are used to reduce this general set of ten
parameters to just three parameters in the isotropic temperature case. A
critical step forward in this study is to identify the dependence of all of the
proposed kinetic mechanisms for turbulent damping in terms of the same set of
fundamental plasma and turbulence parameters. Analytical estimations of the
scaling of each damping mechanism on these fundamental parameters are
presented, and this information is synthesized to produce the first phase
diagram for the turbulent damping mechanisms as a function of driving scale and
ion plasma beta.
