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Abstract

The evolution of auroral display is typically attributed to the interaction between geomagnetic field and solar wind or the self-instability of magnetotail, which can lead to tail magnetic reconnection. Therefore, the motion of aurora arc is often correlated with the movement of the magnetic flux rope in the magnetotail. Previous studies have primarily focused on the equatorward or poleward movement of the aurora arc, which is associated with the radial injection of plasma. However, the azimuthal movement of the west-east aligned thin arc, which is often observed after the north-south aligned streamer, is less explored. Using the THEMIS-ASI data, we manually selected such events and use the object tracking method to calculate the velocity of motion. We will also conduct a coordinated investigation using in-situ THEMIS measurements to investigate the connection between the propagation of the arcs and plasma sheet conditions.