Freja Charging Database Documents
This page contains documents prepared during the SPEE project
related to the Freja Charging Database.
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.
"Analysis of Freja Charging Events: Statistical
occurrence of charging events" by
J.-E. Wahlund, L. Wedin, T. Carrozi, A. I, Eriksson, B. Holback,
L. Anderson and H. Laakso, ESA contract No 11974/96/NL/JG(SC), SPEE-WP130-TN,
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.