  The kinetic evolution of the Orszag-Tang vortex is studied using
collisionless hybrid simulations. In the magnetohydrodynamic regime this vortex
leads rapidly to broadband turbulence. Significant differences from MHD arise
at small scales, where the fluid scale energy dissipates into heat almost
exclusively through the magnetic field because the protons are decoupled from
the magnetic field. Although cyclotron resonance is absent, the protons heat
preferentially in the plane perpendicular to the mean field, as in the corona
and solar wind. Effective transport coefficients are calculated.
