Modeling the electromagnetic ion cyclotron wave‐induced formation of detached subauroral proton arcs

• DOI: 10.1029/2006ja012215
• Publication Date: 2007-08-09T20:05:15Z
• Authors: V. K. Jordanova; M. Spasojevic; M. F. Thomsen
• Keywords: Plasmasphere; Ring current; Noon; Local time

Detached dayside proton arcs have been recently observed at Earth with the IMAGE FUV instrument as subauroral separated from main oval and extending over several hours of local time in afternoon sector. We investigate mechanisms causing precipitation during two arc events that occurred on 23 January 2001 18 June 2001. employ our kinetic physics‐based model coupled a dynamic plasmasphere calculate growth rate electromagnetic ion cyclotron (EMIC) waves self‐consistently evolving ring current H + , O He distributions. Modeled plasmaspheric densities agree well situ observations geosynchronous LANL satellites duskside plasmapause EUV but overestimate drainage plume extent toward noon June. Global images precipitating ions are obtained compared arcs. find EMIC preferentially excited, maximizes, within regions spatial overlap energetic protons plumes along steep density gradients plasmapause. The matches very temporal evolution January. predicted location extends few westward observations, an offset 2 convection electric field is needed to reproduce arc. This study indicates resonant wave‐particle interactions viable mechanism for generation