Inward Motion Of Magnetic Flux Tube Produced By Reconnection In Jupiter's Magnetotail

The radial transport process is key to understanding the dynanmics of the giant Ju-piter's magnetosphere.The Jupiter's magnetosphere are characterized by several inter-nal plasma sources and fast planetary rotation,the centrifugal force cannot be neglected compare with plasma pressure gradient when deal with the cold plasma generated by plasma sources.The action of centrifugal force in Jupiter's rapidly rotating magneto-sphere tends to confine cold plasma towards the equatorial plane.The equatorially-confined plasma moves outward that stretch radially the magnetic field into a thin disc-like structure called the magnetodisc.The radial plasma transport mechanism in these rapidly-rotating magnetospheres is thought to be the centrifugally-driven flux tube in-terchange instability(akin to the gravita-tional Rayleigh-Taylor instability).For a stret-ched magnetic configuration(i.e.,the middle and outer magnetospheres),dense flux tube around plasma sources move outward by centrifugally-driven interchange insta-bility,reconnection of closed flux in magnetotail can generate lower flux tube content and lower flux tube entropy compared to the ambient flux tube,allowing rapid inward motion due to the stability requirement.In this article,through utilizing the self-consistent axisymmetric stationary model of the Jovian magnetosphere including the effect of centrifugal force,the flux tube ge-nerated by reconnection inward motion was studied via applying the "theory of thin filament motion".Based on the thin filament model,some properties of time develop-ment of magnetic flux tube can be obtained from the magnetohydrodynamic(MHD)numerical simulation.The results show that the flux tube generated by reconnection can reach within 10RJ,the velocity of flux tube near the equator portion can reach 350/km/s,and the motion of the flux tube displays a strong planetward flow.Though the density and plasma pressure in the flux tube initially is lower than its neighbors,its density increase gradually owing to compression of volume and plasma pressure rise to values comparable to its neighbors as it moving quickly towards Jupiter.The mo-tion toward the equator of the ionospheric end of the flux tube is delayed relative to the motion toward Jupiter in the equatorial plane.