Direct evidence for prolonged magnetic reconnection at a continuous x‐line within the heliospheric current sheet

Observations by 5 spacecraft of an exceptionally broad (1.85 × 10 6 km) Petschek‐type reconnection exhaust within the heliospheric current sheet, HCS, in the solar wind at 1 AU on 31 August and 1 September 2001 provide convincing direct evidence for prolonged (at least 5 hours) magnetic reconnection at a continuous X‐line in the solar wind. At least 1.2 × 10 24 ergs of magnetic energy were extracted from the HCS in this event and converted to kinetic and thermal energy of the exhaust plasma. The reconnection produced field lines disconnected from the Sun and may have originated inside the point where the solar wind became super‐Alfvénic, thereby slightly reducing the amount of open magnetic flux present in the heliosphere.