Short-Period Flapping Motion of Current Sheet in Saturn's Magnetosphere

Abstract

The flapping motion of the current sheet is a common dynamic phenomenon in the planetary magnetosphere and plays an important role in the transportation of energy and disturbances. Based on the measurements from the Cassini spacecraft, we investigate the short-period flapping motions of the current sheet characterized by periods significantly much smaller than the planetary rotation cycle in Saturn's magnetosphere. Employing the Minimum Variance Analysis (MVA) method, a new technique is developed to distinguish the propagation of current sheet flapping in the radial and azimuthal directions. A total of 105 short-period current sheet flapping events have been detected in Saturn's magnetosphere. The global spatial distribution of these events is provided, and their respective propagation directions have been identified. Further discussions are conducted on the potential sources of the short-period current sheet flapping in Saturn's magnetosphere, including magnetic reconnection, Titan, fast plasma flow, planetary period oscillations, and instabilities near the magnetopause.