Fig. 3. PIC simulations of strongly externally driven onset of magnetotail reconnection.

a–c Colors show the normal magnetic field B_N (in unit of B₀) in the L–N plane at pre-reconnection phase ($t=52{\mathrm{\Omega }}_{\mathrm{i}0}^{-1}$), electron reconnection phase ($t=63{\mathrm{\Omega }}_{\mathrm{i}0}^{-1}$), and ion reconnection phase ($t=90{\mathrm{\Omega }}_{\mathrm{i}0}^{-1}$), respectively. The black curves represent the magnetic field lines in the reconnection plane. d–i Profiles, along N = 0, of V_eL (in unit of V_eA), V_iL (in unit of V_A), E_M (in unit of V_AB₀), V_eL (in unit of V_eA), V_iL (in unit of V_A), and j · E′ (in unit of $e{n}_0{V}_{\mathrm{A}}^2{B}_0$) at pre-reconnection phase ($t=52{\mathrm{\Omega }}_{\mathrm{i}0}^{-1}$, black curves), electron reconnection phase ($t=63{\mathrm{\Omega }}_{\mathrm{i}0}^{-1}$, red curves), and ion reconnection phase ($t=90{\mathrm{\Omega }}_{\mathrm{i}0}^{-1}$, blue curves). The dashed line with an arrow in b represents the virtual trajectory of the MMS spacecraft across the electron reconnection region, along L = −16.1d_i at $t=63{\mathrm{\Omega }}_{\mathrm{i}0}^{-1}$. The red arrows in f, i mark the location of the electron reconnection site.