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Cluster Status Report - April 2005

Cluster Status Report - April 2005

Mission StatusThe four spacecraft and instruments are operating nominally. The short eclipse (less than 1 hour) season has been passed successfully. On spacecraft 1, one of the two batteries had a voltage drop about 3 minutes before the end of the eclipse and the second battery was not powerful enough to keep the spacecraft and instruments working. A switch over from the main on-board computer to the redundant one triggered and all instruments were switched off. After re-configuring the spacecraft, the instruments were successfully switched back on. To prevent this problem from happening again, a third battery was brought on line on each of the four spacecraft.

Operations and Archiving

JSOC and ESOC operations are continuing nominally. The data return from January 2005 to early March 2005 was above 99.1%.

The Cluster Active Archive is progressing well. The first data have been delivered to the archive and it is planned to have most of 2001 data by May 2005. The start-up of the archive has been slower than expected but now with the formats and metadata dictionary defined for all instruments, we expect to recover the delay. The implementation review is planned for end of May 2005.

Science Highlights

Magnetic reconnection on the Earth's magnetopause is considered to be the most efficient mechanism for solar material to penetrate the Earth's magnetic shield. Complex geometrical properties of a transient and spatially confined type of reconnection have been observed in the past but so far not explained, due to high velocity of the magnetopause and the use of single spacecraft measurements. A case study based on multipoint measurements by the Cluster mission reveals, for the first time, a direct observation of a 3D magnetic field topology at the magnetopause, resulting from magnetic reconnection at multiple sites, which could explain these geometrical properties. It also shows a direct view of the entry of particles through the magnetopause.

High-speed flows of plasma (BBF), propagating from the magnetotail to the Earth at velocities higher than 300 kms-1, are the carriers of decisive amounts of mass, energy and magnetic flux. A statistical study based on multipoint measurements by Cluster reveals, for the first time, their typical spatial scale. More than 1600 data points of Earthward flow events were used to deduce the size of the BBFs around 2–3 RE in the dawn-dusk direction and 1.5–2 RE in the north-south direction.

Last Update: 1 September 2019
19-May-2024 20:44 UT

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