Locating the source field lines of Jovian decametric radio emissions

作者：YuMing Wang,XianZhe Jia,ChuanBing Wang,Shui Wang,Vratislav Krupar

摘要：Decametric(DAM) radio emissions are one of the main windows through which one can reveal and understand the Jovian magnetospheric dynamics and its interaction with the moons. DAMs are generated by energetic electrons through cyclotron-maser instability. For Io(the most active moon) related DAMs, the energetic electrons are sourced from Io volcanic activities, and quickly trapped by neighboring Jovian magnetic field. To properly interpret the physical processes behind DAMs, it is important to precisely locate the source field lines from which DAMs are emitted. Following the work by Hess et al.(2008, 2010), we develop a method to locate the source region as well as the associated field lines for any given DAM emission recorded in a radio dynamic spectrum by, e.g.,Wind/WAVES or STEREO/WAVES. The field lines are calculated by the state-of-art analytical model, called JRM09(Connerney et al., 2018).By using this method, we may also derive the emission cone angle and the energy of associated electrons. If multiple radio instruments at different perspectives observe the same DAM event, the evolution of its source region and associated field lines is able to be revealed. We apply the method to an Io-DAM event, and find that the method is valid and reliable. Some physical processes behind the DAM event are also discussed.

发文机构：Chinese Academy of Sciences Key Laboratory of Geospace Environment Chinese Academy of Sciences Center for Excellence in Comparative Planetology Mengcheng National Geophysical Observatory Department of Climate and Space Sciences and Engineering Universities Space Research Association NASA Goddard Space Flight Center Department of Space Physics

关键词：RADIOdecametricEMISSIONSJovianMAGNETOSPHEREENERGETICELECTRONS

分类号： TN9[电子电信—信息与通信工程]