Low-charge-state heavy ions upstream of earth's bow shock and sunward fluxof ionospheric O+1, N+1, and O+2 ions: Geotail observations

Energetic similar to 10-210 keV/e low-charge-state heavy ions (LCSHI) were measured sunward of Earth's bow shock (to X similar to 30 R-E) during numer ous intervals lasting from minutes to hours using Geotail/STICS in 1995-199 8. LCSHI fluxes are strong and continuous in a few tens of intervals, durin g which a strong component of ionospheric origin O+1, N+1, and O+2 streams sunward on nearly radial IMF. Most often though only 'trace' levels are pre sent. LCSHI flux is typically, but not exclusively, observed during diffuse upstream ion events. LCSHI are accompanied by sunward energetic electron b ursts in three of the four cases shown and twice by enhanced IMF fluctuatio ns. As O+1 streams sunward in the spacecraft frame during the strongest cas e, H+, He+2, He+1, and O+6 fluxes have weak anisotropies and the H+ energy spectrum is kappa-like. The strongest LCSHI fluxes tend to occur duskward o f local noon during disturbed geomagnetic conditions. On average, LCSHI flu x is more uniformly distributed across the dayside.