Figure 1

(a–f) Wind measurements of density, magnetic field, velocity ($V_x$ has been shifted by $500\mathrm{km}/\mathrm{s}$), and temperature between 16:00–18:00 UT on October 3, 2000 with a cadence of three seconds. The MCBL is shown by the dotted lines; the dashed lines marked by A1 and A2 inside the MCBL represent the reconnection exhaust boundaries at 16:46 UT and 16:58 UT, respectively.Reuse & Permissions

Figure 2

(a) Geometric configuration of the reconnection event; the reconnection jets and $X$ lines are shown in red; the following MC is sketched in green. (b–d) ACE measurements of magnetic field and velocity in the LMN coordinate system ($V_L$ has been shifted by $-500\mathrm{km}/\mathrm{s}$). The dashed lines stand for the exhaust boundaries. (e–g) Wind measurements of magnetic field and velocity in the LMN coordinate system ($V_L$ has been shifted by $-500\mathrm{km}/\mathrm{s}$). The black solid lines show the predicted velocity. In the predication, we calculate the theoretical velocity by the Walen relation: $V_{\mathrm{pre}}=V_{\mathrm{ref}}\pm {\rho }_{\mathrm{ref}}^{1/2}(1-{\alpha }_{\mathrm{ref}}{)}^{1/2}(\mathbf{B}/\rho -{\mathbf{B}}_{\mathrm{ref}}/{\rho }_{\mathrm{ref}})/{\mu }_0^{1/2}$ [22, 23]. Here $V$, $B$, $\rho$ represent normal meanings, while $\alpha \equiv (p_{\parallel }-p_{\perp }){\mu }_0/B^2$, the pressure anisotropy factor, is assumed to be zero. The subscript “ref” denotes the reference time at the leading (trailing) edge of the exhaust and “pre” denotes the calculated velocity across the region. The positive (negative) sign is chosen for the trailing (leading) edge of the exhaust. The leading and trailing edge predictions merge at 16:53 UT.Reuse & Permissions

Figure 3

Wind measurements of 10 eV–500 keV electron normalized fluxes in parallel (a), perpendicular (b) and antiparallel (c) directions, respectively. (d) 5–5000 keV proton normalized flux (omni). All the fluxes are divided by the background flux $F_0$ at every energy band for normalizing. The background flux $F_0$ is chosen as the mean flux of a nearby quiet period (between 16:00 and 16:30 UT) for each energy band. The missing (invalid) data are shown by blank. (e) Normalized fluxes at 16:55 UT.Reuse & Permissions

Figure 4

(a) MHD parallel AMR simulation of the MC driving reconnection in the solar wind (left) and the zoomed result (right). The magnetic field lines are sketched by the solid curves with arrows. Detailed simulation methods are given in 19 and references therein. The radius of the MC projected in the LN plane is 300 Re and the whole computation region is $L\times N=2000\mathrm{Re}\times 1200\mathrm{Re}$. Other input parameters are chosen from Fig. 1, 2 (b) MHD parallel AMR simulation of magnetic reconnection in the reconnection region. The magnetic field is sketched by the dotted lines. The initial simulation conditions similar to the geospace environmental modeling reconnection challenge with a guide field [30]. The aspect ratio of the Harris sheet is set to 100 and the system size is $L\times N=100d_i\times 10d_i$; the initial configurations include $6\mathrm{km}/\mathrm{s}$ inward driven flows at both sides and a uniform 5 nT guide field. Other parameters are directly obtained from Figs. 1, 2. (c) The electron energy $E_k$ as a function of its position in L direction. Colored rectangles mark the three typical motions. (d) The electron energy $E_k$ (blue) and its $\mathit{M}$ position (red) as a function of time during the whole acceleration process.Reuse & Permissions