Continuous reconnections inferred from observations by TC-1 during IMF Bz≈0

During a one-hour interval of IMF Bz≈0, the equatorial spacecraft Double Star named TC-1 encountered magnetopause multi times at MLT of 08:00, latitude = -27 degrees. During each encounter, reconnection jets were oberserved with velocities up to more than 500 km/s, significantly higher than the background flows of the magnetosheath. The fast flows match the theoretical prediction of Alfvenic acceleration well. The mainly southward and tailward flow of the jets indicate that the spacecraft was located south of the reconnection site, consistent with models of reconnection with such IMF conditions. The accelerated flows were observed lasting for about one hour, with some modulation by the oscillation of the magnetopause, but no reversals in the direction of Vz were found during the interval, implying that reconnection at magnetopause northward to the spacecraft might be continuously active under such IMF conditions.