One of the major discoveries of Hinode’s Extreme-ultraviolet Imaging Spectrometer (EIS) is the presence of upflows at the edges of active regions. As active regions are magnetically connected to the large-scale field of the corona, these upflows are a likely contributor to the global mass cycle in the corona. Here we examine the driving mechanism(s) of the very strong upflows with velocities in excess of 70 km s⁻¹, known as blue-wing asymmetries, observed during the eruption of a flux rope in AR 10977 (eruptive flare SOL2007-12-07T04:50). We use Hinode/EIS spectroscopic observations combined with magnetic-field modeling to investigate the possible link between the magnetic topology of the active region and the strong upflows. A Potential Field Source Surface (PFSS) extrapolation of the large-scale field shows a quadrupolar configuration with a separator lying above the flux rope. Field lines formed by induced reconnection along the separator before and during the flux-rope eruption are spatially linked to the strongest blue-wing asymmetries in the upflow regions. The flows are driven by the pressure gradient created when the dense and hot arcade loops of the active region reconnect with the extended and tenuous loops overlying it. In view of the fact that separator reconnection is a specific form of the more general quasi-separatrix (QSL) reconnection, we conclude that the mechanism driving the strongest upflows is, in fact, the same as the one driving the persistent upflows of ≈10 – 20 km s⁻¹ observed in all active regions.

Hinode 的极紫外成像光谱仪(EIS)的主要发现之一是在活动区域​​的边缘存在上升流。由于活动区域与日冕的大规模场磁连接，这些上升流可能是日冕中全球质量循环的一个因素。在这里，我们检查了速度超过 70 km s ^-1的非常强烈的上升流的驱动机制，称为蓝翼不对称，在 AR 10977 中的磁通绳喷发期间观察到（喷发耀斑 SOL2007-12- 07T04:50）。我们使用日出/EIS 光谱观测与磁场建模相结合，以研究活动区域的磁拓扑与强上流之间可能存在的联系。大尺度场的势场源表面 (PFSS) 外推显示了四极配置，分离器位于通量绳上方。在通量绳喷发之前和期间，由沿着分离器的诱导重联形成的场线在空间上与上升流区域中最强的蓝翼不对称性相关。当活动区域的密集而热的拱廊回路与覆盖在它上面的延伸和脆弱的回路重新连接时，产生的压力梯度驱动了流动。鉴于分隔符重连是更一般的准分隔符 (QSL) 重连的一种特定形式，^-1在所有活动区域中观察到。