Revisiting a classic: the Parker-Moffatt problem

The interaction of two colliding Alfv\'en wave packets is here described by means of magnetohydrodynamics (MHD) and hybrid kinetic numerical simulations. The MHD evolution revisits the theoretical insights described by Moffatt, Parker, Kraichnan, Chandrasekhar and Els\"asser in which the oppositely propagating large amplitude wave packets interact for a finite time, initiating turbulence. However, the extension to include compressive and kinetic effects, while maintaining the gross characteristics of the simpler classic formulation, also reveals intriguing features which go beyond the pure MHD treatment.