title: Images of Io's Sodium Cloud.
abstract: The first direct images of Io's sodium cloud are reported and analyzed. The observed cloud extends for more than 10(5) kilometers along Io's orbit and is a somewhat "banana-shaped" partial toroid. More sodium atoms precede Io than follow it. A model based on the escape of sodium from a specific localized area on Io provides a reasonable fit to the observed intensity distribution whereas isotropic escape does not.
authors.forename: D L
authors.initials: DL
authors.lastname: Matson
authors.forename: B A
authors.initials: BA
authors.lastname: Goldberg
authors.forename: T V
authors.initials: TV
authors.lastname: Johnson
authors.forename: R W
authors.initials: RW
authors.lastname: Carlson