Schematic of the MRD model for SNR, with the Crab Nebula as an example. The upper panel shows the three-layer structure of the detonation front composed of the upstream ISM, the Neumann layer, and the downstream SNR, with the flow speed (in reference to the shock front) and local Mach number in each region indicated. Here the upstream magnetic field is neglected, and the Neumann layer magnetic field is ∼10 times the SNR magnetic field, with the ratio equal to the density ratio when assuming that the magnetic field is frozen to the fluid. The Neumann layer is where MR occurs to transfer the magnetic field energy to both the fluid thermal energy and to the kinetic energy of high-energy non-thermal charged particles. Following (and even within) the Neumann layer, non-thermal particles will first produce γ-ray and X-ray radiation, while radio and optical emissions with lower energy spread over the length of SNR of a few parsecs. The two lower panels show the variation of density and temperature in the three layers as a reference (e.g., Figure 1).