We use combined Ultraviolet Coronagraph Spectrometer and Large Angle Spectroscopic Coronagraph data to determine the O5+ outflow velocities as a function of height along the axis of an equatorial streamer at solar minimum and as a function of latitude (at 2.3 R☉ from Sun center). The results show that outflow increases rather abruptly in the region between 3.6 and 4.1 R☉ near the streamer cusp and gradually increases to ~90 km s-1 at ~5 R☉ in the streamer stalk beyond the cusp. The latitudinal variation at 2.3 R☉ shows that there is no outflow (within the measurement uncertainties) in the center of the streamer, called the core, and that a steep increase in outflow occurs just beyond the streamer legs, where the O VI λ1032 intensity relative to H I λ1216 (Lyα) is higher than in the core. Velocity variations in both height and latitude show that the transitions from no measurable outflow to positive outflow are relatively sharp and thus can be used to infer the location of the transition from closed to open field lines in streamer magnetic field topologies. Such information, including the densities and kinetic temperatures derived from the observations, provides hard constraints for realistic theoretical models of streamers and the source regions of the slow solar wind.
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机译：我们结合使用紫外线日冕仪和大角度日冕仪数据来确定O5 +流出速度，该速度是在太阳最低时沿赤道拖缆轴线的高度与纬度（从太阳中心起2.3R☉）的函数。结果表明，在流道尖附近，流率在3.6和4.1R☉之间的区域突然增加，在流道尖附近，流道茎在〜5R☉处，流出量逐渐增加到〜90 km s-1。在2.3R☉处的纬度变化表明，在拖缆的中心（称为岩心）没有流出（在测量不确定性范围内），并且流出的急剧增加正好出现在拖缆的支腿附近，在此处O VIλ1032强度相对于HIλ1216（Lyα）高于核心。高度和纬度的速度变化表明，从无可测量的流出到正流出的过渡相对较尖锐，因此可以用来推断流场磁场拓扑结构中从封闭磁场到开放磁场的过渡位置。这样的信息，包括从观测得到的密度和动力学温度，为拖缆和慢太阳风的源区的现实理论模型提供了严格的约束。
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