Further on the October 31, 1977 upstream event: A response to D. C. Ellison

Over the past decade, and on the basis of simultaneous multi‐spacecraft observations, we have shown that energetic ions escape upstream from the earth's bow shock by drifting through the magnetospheric and magnetosheath fields from their source inside the plasma sheet [ Sarris et al. , 1978; Krimigis and Sarris , 1979]. Furthermore, Voyager 1 and 2 observations, during their encounters with Jupiter [ Zwickl et al. , 1980; Krimigis et al. , 1985], and more recently with Uranus [ Krimigis et al , 1986], have also shown that energetic ions of magnetospheric origin leak upstream from the planetary bow shocks.