Comment on 'Energetic heavy ions observed upstream of the Earth's bow shock by the STEP/EPACT instrument on WIND'

In this paper we re-examine some upstream ion observations obtained by WIND between Jan. 20, 1995 - Feb. 19, 1995 [Mason et al.; 1996]. Our analysis shows that the peak-to-background flux of energetic ions decreases as the flux of solar / interplanetary ambient ion population increases, which is a behavior confirmed in the case of magnetospheric ions [Anagnostopoulos et al., 1995]. The whole set of Mason' et al. heavy ion characteristics is discussed in terms of various sources, and we find that leakage of magnetospheric ions is most probably the principal source of the ion events analysed.