We report observations of neutral atoms from the solar wind in the Earth's
vicinity with the low-energy neutral atom (LENA) imager on the Imager for M
agnetopause-to-Aurora Global Exploration (IMAGE) spacecraft. This instrumen
t was designed to be capable of looking at and in the direction of the Sun.
Enhancements in the hydrogen count rate in the solar direction are not cor
related with either solar ultraviolet emission or suprathermal ions and are
deduced to be due to neutral particles from the solar wind. LENA observes
these particles from the direction closest to that of the Sun even when the
Sun is not directly in LENA's 90 degrees field of view. Simulations show t
hat these neutrals are the result of solar wind ions charge exchanging with
exospheric neutral hydrogen atoms in the postshock flow of the solar wind
in the magnetosheath. Their energy is inferred to exceed 300 eV, consistent
with solar wind energies, based on simulation results and on the observati
on of oxygen ions, sputtered from the conversion surface in the time-of-fli
ght spectra. In addition, the sputtered oxygen abundance tracks the solar w
ind speed, even when IMAGE is deep inside the magnetosphere. These results
show that low-energy neutral atom imaging provides the capability to direct
ly monitor the solar wind flow in the magnetosheath from inside the magneto
sphere because there is a continuous and significant flux of neutral atoms
originating from the solar wind that permeates the magnetosphere.