This page contains public documents prepared during the SPEE project. They are available in PDF format only. 

- "Analysis of Freja Charging Events: Charging Events Identification and case studies" by J.-E. Wahlund, L. Wedin,  A. I, Eriksson, B. Holback and L. Anderson, ESA contract No 11974/96/NL/JG(SC), SPEE-WP110-TN, March 1999

A detailed analysis of at least 10 Freja charging events from the statistical study (WP 130), which illustrate the different (if several) charging processes detected in the Freja data selected over the whole altitude range covered by the Freja spacecraft. This analysis will include the precise electron and ion energy distributions, lightning characteristics, geomagnetic location and activity conditions, as well as the cold plasma density and temperature characteristics. The aim of the study will be to identify the precise mechanism behind the charging events that operate at Freja altitudes. The detailed study of these events will be compared to similar studies carried out with the DMSP and ARCAD spacecraft, and the electrostatic environment will be investigated for the Freja case with this comparison in mind.

Technical Note: Page 1-32(6.1 Mb), Page 33-53(6.3 Mb), Page 54-92(5.4 Mb).

A statistical study based on a substantial amount of the Freja spacecraft data in order to establish the occurrence and intensity characteristics of spacecraft charging events along the Freja orbits, using the full altitude extent (600-1800 km) of the Freja measurements. The statistics shall be complemented with information on the environmental characteristics during charging events. In particular, the cold plasma density, cold plasma temperatures, energetic electron and ion energy distributions, lightning conditions, geomagnetic location (MLT, CGLAT, UT), geomagnetic activity (Ap, Kp, solar wind Bz components), and possible variations during the Freja operation time (1992-1995) will be investigated and documented.

Technical Note: PDF Document(3.4 Mb)