  A local turbulence model is developed to study energy cascades in the
interstellar medium (ISM) based on self-consistent two-dimensional fluid
simulations. The model describes a partially ionized magnetofluid interstellar
medium (ISM) that couples a neutral hydrogen fluid with a plasma primarily
through charge exchange interactions. Charge exchange interactions are
ubiquitous in warm ISM plasma and the strength of the interaction depends
largely on the relative speed between the plasma and the neutral fluid. Unlike
small length-scale linear collisional dissipation in a single fluid, charge
exchange processes introduce channels that can be effective on a variety of
length-scales that depend on the neutral and plasma densities, temperature,
relative velocities, charge exchange cross section and the characteristic
length scales. We find, from scaling arguments and nonlinear coupled fluid
simulations, that charge exchange interactions modify spectral transfer
associated with large scale energy containing eddies. Consequently, the warm
ISM turbulent cascade rate prolongs spectral transfer amongst inertial range
turbulent modes. Turbulent spectra associated with the neutral and plasma ISM
fluids are therefore steeper than those predicted by Kolmogorov's
phenomenology.
