Shock is produced by supersonic flow toward the stationary reflective wall to the right. Continuous inflow of new particles occurs at the left boundary. Inflow velocity is U₀, a particle’s total velocity is V, the local frame particle velocity is V_L, and thermal velocity  ⟨ V_L ⟩  = v₀. The two circles represent one typical particle in the upstream region and one in the downstream region, respectively. The vertical solid line represents the shock front, the vertical dashed line represents the FEB, the velocity of the shock is V_shock, size of the foreshock region is X_feb = 90, the upstream flow velocity U = U₀, and the downstream flow velocity is U = 0. The magnetic field B₀ and inflow velocity U₀ are both normal to the shock front (see Knerr et al. 1996).