20171102Jupiter's Equatorially Anti-symmetric Gravitational Field and its Interior Dynamics
报告人简介: Dr. Dali Kong obtained his B.Sc. degree in 2008 from Dept. of Astronomy, Nanjing University, China. He then obtained his PhD degree in 2012, under the supervision of Prof. Keke Zhang, from College of Engineering, Mathematics and Physical Sciences, University of Exeter, UK. After that, he continued working in Exeter as a Research Fellow under the support of a Leverhulme Fellowship until May 2017. Dr. Kong was selected by Chinese government's 'Youth 1000 program' in 2017. He was therefore offered a research scientist position in Shanghai Astronomical Observatory, Chinese Academy of Sciences. His main areas of researches are theoretical and computational fluid mechanics, high performance computing and planetary sciences. By 2017, Dr Kong has published more than 30 peer-reviewed journal articles and delivered 5 invited talks in international conferences. He was awarded the Royal Astronomical Society 'Winton Capital Prize' in 2016. 报告内容简介: The equatorially antisymmetric gravitational field of Jupiter is nearly unaffected by its rotational distortion and, hence, it provides a direct window into the antisymmetric fluid motion taking place in Jupiter's interior. We derive, using the high-precision antisymmetric gravitational data acquired by the Juno spacecraft and the thermal-gravitational wind equation in spherical geometry (a two-dimensional kernel integral equation with the Green's function in its integrand), the location/structure/amplitude of the equatorially antisymmetric zonal flow of Jupiter without making any prior assumptions about these features. We show that the equatorially antisymmetric zonal flow is primarily confined in the outer envelope approximately in 0.8R < r < R, where R is Jupiter's radius, has a typical speed about 5m/s, and alternates in the prograde and retrograde direction. The antisymmetric zonal flow most likely derives from instabilities in the symmetric flow. Therefore the symmetric zonal flow observed at the surface must extend downward into the region where the antisymmetric winds are generated. Our results suggest that the Jovian convective dynamo is operating in the region approximately r < 0.8R where the electrical conductivity is believed to be sufficiently high. The location/structure/amplitude of the equatorially antisymmetric zonal flow in Jupiter's interior derived from the Jovian equatorially antisymmetric gravitational field may answer the long-standing scientific question about the dynamics/depth of the cloud-level zonal flow on Jupiter.