title: Energetic particles at venus: galileo results.
abstract: At Venus the Energetic Particles Detector (EPD) on the Galileo spacecraft measured the differential energy spectra and angular distributions of ions >22 kiloelectron volts (keV) and electrons > 15 keV in energy. The only time particles were observed by EPD was in a series of episodic events [0546 to 0638 universal time (UT)] near closest approach (0559:03 UT). Angular distributions were highly anisotropic, ordered by the magnetic field, and showed ions arriving from the hemisphere containing Venus and its bow shock. The spectra showed a power law form with intensities observed into the 120- to 280-keV range. Comparisons with model bow shock calculations show that these energetic ions are associated with the venusian foreshock-bow shock region. Shock-drift acceleration in the venusian bow shock seems the most likely process responsible for the observed ions.
authors.forename: D J
authors.initials: DJ
authors.lastname: Williams
authors.forename: R W
authors.initials: RW
authors.lastname: McEntire
authors.forename: S M
authors.initials: SM
authors.lastname: Krimigis
authors.forename: E C
authors.initials: EC
authors.lastname: Roelof
authors.forename: S
authors.initials: S
authors.lastname: Jaskulek
authors.forename: B
authors.initials: B
authors.lastname: Tossman
authors.forename: B
authors.initials: B
authors.lastname: Wilken
authors.forename: W
authors.initials: W
authors.lastname: Stüdemann
authors.forename: T P
authors.initials: TP
authors.lastname: Armstrong
authors.forename: T A
authors.initials: TA
authors.lastname: Fritz
authors.forename: L J
authors.initials: LJ
authors.lastname: Lanzerotti
authors.forename: J G
authors.initials: JG
authors.lastname: Roederer