energy equipartition between particles and magnetic field, $\varepsilon_eN=B^2/8\pi$, and the conservation of the particle number flux, $4\pi r^2cN\sim$ constant, in the MSP wind region. Here, $N$ is the number density of electrons/positrons. The number density can be described as $$N=N_{\rm lc}\left(\frac{R_{\rm lc}}{r}\right)^2=\frac{B_{\rm lc}\Omega\kappa}{2\pi ce}\left(\frac{R_{\rm lc}}{r}\right)^2,$$ where $\kappa$ is the multiplicity of electrons/positrons, $N_{\rm lc}$ and $B_{\rm lc}$ are the number density and the magnetic field at the light cylinder, respectively. We assume the magnetic field configuration as pure dipole ($B\propto r^{-3}$) within light cylinder. Outside the light cylinder, we assume the conservation of the energy flux of the magnetic field, $Br\sim$ constant. Using these assumptions, the typical energy of electrons/positrons $\varepsilon_e$ can be described as $$\varepsilon_e = \frac{e\psi_{\max}}{\kappa} \sim 50\kappa^{-1}\left(\frac{B_0}{10^{8.5}{\rm G}}\right)\left(\frac{\Omega}{10^3{\rm s^{-1}}}\right)^2\left(\frac{R}{10^{6}{\rm cm}}\right)^3 {\rm TeV},
\label{eq:2.1}$$ where $\psi_{\rm max}$ is the electric potential difference across the open magnetic field lines described as $$\psi_{\max}=\frac{B_0\Omega^2R^3}{2c^2}\sim 5\times10^{13}\left(\frac{B_0}{10^{8.5}{\rm G}}\right)\left(\frac{\Omega}{10^3{\rm s^{-1}}}\right)^2\left(\frac{R}{10^{6}{\rm cm}}\right)^3 {\rm Volt}.
\label{eq:2.2}$$ These values are similar to those in the case of white dwarf pulsars (KIK11). Note that the typical energy depends on the pair multiplicity.

Next, we estimate the adiabatic and the radiative cooling of electrons/positrons in the shocked region. The outer shock of the pulsar wind nebula finally decays when 