A plasmapause-like density boundary at high latitudes in Saturn's magnetosphere - Gurnett, DA; Persoon, AM; Kopf, AJ; Kurth, WS; Morooka, MW; Wahlund, J-E; Khurana, KK; Dougherty, MK; Mitchell, DG; Krimigis, SM; Krupp, N (GEOPHYSICAL RESEARCH LETTERS, 2010)