Background and pickup ion velocity distribution dynamics in Titan’s plasma environment: 3D hybrid simulation and comparison with CAPS T9 observations

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• 作者：A.S. Lipatov^a ; ^{Alexander.Lipatov-1@nasa.gov"" rel=""nofollow} ; E.C. Sittler Jr.^b ; ^{Edward.C.Sittler@nasa.gov"" rel=""nofollow} ; R.E. Hartle^b ; ^{Richard.E.Hartle@nasa.gov"" rel=""nofollow} ; J.F. Cooper^b ; ^{John.F.Cooper@nasa.gov"" rel=""nofollow} ; D.G. Simpson^b ; ^{David.G.Simpson@nasa.gov"" rel=""nofollow}
• 关键词：Ionospheres ; Atmospheres ; Induced magnetospheres ; Magnetic barrier ; Alfv&#xe9 ; n wing ; Satellites
• 刊名：Advances in Space Research
• 出版年：2011
• 出版时间：15 September 2011
• 年：2011
• 卷：48
• 期：6
• 页码：1114-1125
• 全文大小：3699 K

文摘

In this report we discuss the ion velocity distribution dynamics from the 3D hybrid simulation. In our model the background, pickup, and ionospheric ions are considered as a particles, whereas the electrons are described as a fluid. Inhomogeneous photoionization, electron-impact ionization and charge exchange are included in our model. We also take into account the collisions between the ions and neutrals. The current simulation shows that mass loading by pickup ions , and is stronger than in the previous simulations when O⁺ ions are introduced into the background plasma. In our hybrid simulations we use Chamberlain profiles for the atmospheric components. We also include a simple ionosphere model with average mass M = 28 amu ions that were generated inside the ionosphere. The moon is considered as a weakly conducting body. Special attention will be paid to comparing the simulated pickup ion velocity distribution with CAPS T9 observations. Our simulation shows an asymmetry of the ion density distribution and the magnetic field, including the formation of the Alfvén wing-like structures. The simulation also shows that the ring-like velocity distribution for pickup ions relaxes to a Maxwellian core and a shell-like halo.