Dust in the wind: The dust geometric cross section at 1 AU based on neutral solar wind observations.

We report observations of the neutral component of the solar wind from the Low Energy Neutral Atom (LENA) imager on the NASA IMAGE spacecraft from year 2001. There is a pronounced annual modulation of the neutral solar wind, and the flux outside of the upstream region is used to place an upper limit on the dust geometric cross section in the sunward direction at 1 AU of Γ1AU < 6×10-19 cm-1. This value agrees with inferences made from the zodiacal light. © 2003 American Institute of Physics [ABSTRACT FROM AUTHOR]