Solitary waves observed in the auroral zone: the Cluster multi-spacecraft perspective - Pickett, JS; Kahler, SW; Chen, LJ; Huff, RL; Santolík, O; Khotyaintsev, Y; Décréau, PM; Winningham, D; Frahm, R; Goldstein, ML; Lakhina, GS; Tsurutani, BT; et al. (COPERNICUS GESELLSCHAFT MBH, 2004)