*Kanako Seki¹, Takuya Hara², Dave A Brain³, Christopher M Fowler⁴, James P McFadden², Jasper S Halekas⁵, Gina A DiBraccio⁶ (1.Graduate School of Science, University of Tokyo, 2.Space Science Laboratory, University of California, Berkeley, USA, 3.LASP, University of Colorado Boulder, USA, 4.Department of Physics and Astronomy, West Virginia University, USA, 5.Department of Physics and Astronomy, University of Iowa, USA, 6.NASA Goddard Space Flight Center, USA)