MAGION 5 Cold Plasma Data

The Czech subsatellite MAGION 5 was launched in August, 1996, together with the main INTERBALL 2 spacecraft, into an orbit with inclination of ~65°, orbit perigee of ~1.2 RE (RE is the Earth's radius), and apogee of ~ 4 RE. Unfortunately, after one-day operation the communication with the subsatellite was lost, and it was managed to be restore only in 20 months after launching. Nevertheless, all spacecraft systems operated normally. For thermal plasma measurements in the Earth's plasmasphere the MAGION-5 carried the plasma analyzer with retarding potential PL-48 that was a part of the KM-7c instrument complex set. The data were taken since August, 1999, when the instrument-carrying bar was deployed, till July, 2001, when the satellite's service life actually came to an end. The energy spectra of cold protons were measured for 0.4 s, once in ~8 s. The nearly 6-h orbital period allowed the plasmasphere to be crossed 4 times a day. However, by virtue of various reasons, the data are available, in the majority of cases, only from one inbound leg of an orbit per day, and only occasionally the data could be obtained from two successive inbound orbit legs.