title: Magnetic fields at the solar wind termination shock.
abstract: A transition between the supersonic solar wind and the subsonic heliosheath was observed by Voyager 1, but the expected termination shock was not seen owing to a gap in the telemetry. Here we report observations of the magnetic field structure and dynamics of the termination shock, made by Voyager 2 on 31 August-1 September 2007 at a distance of 83.7 au from the Sun (1 au is the Earth-Sun distance). A single crossing of the shock was expected, with a boundary that was stable on a timescale of several days. But the data reveal a complex, rippled, quasi-perpendicular supercritical magnetohydrodynamic shock of moderate strength undergoing reformation on a scale of a few hours. The observed structure suggests the importance of ionized interstellar atoms ('pickup protons') at the shock.
authors.affiliation: NASA/Goddard Space Flight Center, Greenbelt, Maryland 20771, USA. Leonard.F.Burlaga@nasa.gov
authors.forename: L F
authors.initials: LF
authors.lastname: Burlaga
authors.forename: N F
authors.initials: NF
authors.lastname: Ness
authors.forename: M H
authors.initials: MH
authors.lastname: Acuña
authors.forename: R P
authors.initials: RP
authors.lastname: Lepping
authors.forename: J E P
authors.initials: JE
authors.lastname: Connerney
authors.forename: J D
authors.initials: JD
authors.lastname: Richardson