Statistics on Jupiter's Current Sheet With Juno Data: Geometry, Magnetic Fields and Energetic Particles

摘要

Jupiter's magnetosphere contains a current sheet of huge size near its equator. The current sheet not only mediates the global mass and energy cycles of Jupiter's magnetosphere, but also provides a site for many localized dynamic processes, such as reconnection and wave-particle interaction. To correctly evaluate its role in these processes, a statistical description of the current sheet is required. To this end, here we conduct statistics on Jupiter's current sheet, by using four-year Juno data obtained in the 20-100 Jupiter radius, 0-6 local time magnetosphere. The statistics show the thickness of the current sheet is comparable with the gyro-radius of ions dominating the plasma pressure. Magnetic fields in the current sheet decrease in power-law with increasing radial distances. At given energy, the flux of energetic electrons and protons increases with decreasing radial distances. On the other hand, at given radial distances, the flux decreases in power-law with increasing energy. The flux also varies with the distances to the current sheet center. The corresponding relationship can be described by a Gaussian function peaking at the current sheet center. In addition, the statistics show the flux of oxygen- and sulfur-group ions is comparable with the flux of protons at the same energy and radial distances, indicating the non-negligible role of heavy ions in the current sheet dynamics. From these results, a statistical model is constructed, providing us with a starting point of understanding the dynamics of the whole Jupiter's magnetosphere.