 FREJA project in Oulu
spaceweb@oulu.fi - last update: 14 November 2000 (RR)
 The second scientific satellite from Sweden, FREJA, was launched on 6
October 1992, in a Chinese Long March II rocket. It ceased operations on 14 October 1996.
For more information about the project, see Lundin et al. (1994a,b, 1998).
FREJA is the first satellite from which the Space Physics Group of Oulu has received
data via an official co-investigator (co-I) status. This was gained by taking part in the
construction of the electric field instrument of the Alfvén Laboratory
of KTH, Stockholm (where the
launch photo comes from), which had already built similar type of instrument for VIKING (see Marklund et al., 1994). In the software side, the group
has coded the ISDAT data base
handler and a client program for the instrument.
The high sampling rate of the electric field instrument (6144 samples/s in burst mode)
allow the data to be used in different kind of studies, from auroral arc related spatial
electric fields to pulsations in ULF
and VLF range. For example,
the Oulu group has studied EMIC waves (Mursula et al., 1994; Bräysy et al., 1998) and
substorm effects (Persson et al., 1994).
Freja related publications by the Oulu group
- Marklund, G. T., L. G. Blomberg, P.-A. Lindqvist, C.-G. Fälthammar, G. Haerendel, F. S.
Mozer, A. Pedersen, and P. Tanskanen, The double probe electric field experiment on
Freja: experiment description and first results, Space Sci. Rev., 70,
483-508, 1994.
- Mursula, K., L. G. Blomberg, P.-A. Lindqvist, G. T. Marklund, T. Bräysy, R.
Rasinkangas, and P. Tanskanen, Dispersive Pc1 bursts observed by Freja, Geophys.
Res. Lett., 21, 1851-1854, 1994.
- Persson, M.A.L., H.J. Opgenoorth, T.I. Pulkkinen, A.I. Eriksson, P.O. Dovner, G.D.
Reeves, R.D. Belian, M. André, L.G. Blomberg, R.E. Erlandson, M.H. Boehm, A.T. Aikio,
and I. Häggstöm, Near-earth substorm onset: A coordinated study, Geophys. Res. Lett.,
21, 1875-1878, 1994.
- Bräysy, T., K. Mursula, and G. Marklund, Ion cyclotron waves during a
great magnetic storm observed by Freja double-probe electric field instrument, J.
Geophys. Res., 103, 4145-4155, 1998.
Other references
- Lundin, R., G. Haerendel, and S. Grahn, The Freja project, Geophys. Res. Lett., 21,
1823-1826, 1994a.
- Lundin, R., G. Haerendel, and S. Grahn, The Freja science mission, Space Sci. Rev.,
70, 405, 1994b.
- Lundin, R., G. Haerendel, and S. Grahn, Introduction to special section: The Freja
mission, J. Geophys. Res., 103, 4119-4123, 1998.
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