Ion upflow observed in the polar ionosphere

Ion upflow has been investigated by use of ESR (EISCAT Svalbard Radar), SuperDARN, ACE satellite and CHAMP satellite. The field-aligned ion upflows were observed by ESR, which occurred in night-time between 16 and 17, April 2002, and 19 June 2004. However, ESR didn't show remarkable increase of electron density, electron temperature and ion temperature, which are generated by auroral particle precipitation or frictional heating. The Solar wind parameters were obtained by ACE satellite. SuperDARN showed variation of convection electric field depending on By component of Interplanetary Magnetic Field. CHAMP satellite observed also variations of neutral density, neutral wind, ion density and electron temperature along the satellite orbits. At the time, ESR was in the polar cap region. Our analyses may suggest that the ion upflow observed by ESR was generated in the upwind region of plasma convection in the high-latitude ionosphere and was moving to ESR station by the convection.