3 Observations
We used ASI images and N-S keogram to identify the detachment of arcs based on visual inspection. Figure 1 shows the typical ASI images at red-line (630.0 nm) and green-line (557.7 nm) for red arc (upper panel A), red+green arc (middle panel B), and STEVE (bottom panel C). Spectrally pure red-line emission is considered as red arcs, not associated with simultaneous observation in the green-line (panel A). The arc in red-line with simultaneous emission in green-line is referred as red+green arc (panel B). STEVE is a narrow bright arc compared to normal red arc, exhibiting wavy structure along the arc, and sometimes also picket fence structure in the green-line (panel C).