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Ann. Geophys., 20, 471-476, 2002
www.ann-geophys.net/20/471/2002/
© European Geosciences Union 2002
Relationship of upflowing ion beams and conics around the dayside cusp/cleft region to the interplanetary conditions
W. Miyake1, T. Mukai2, and N. Kaya3
1Communications Research Laboratory, 4-2-1 Koganei, Tokyo 184-8795, Japan
2The Institute of Space and Astronautical Science, Yoshinodai, Sagamihara 229-8510, Japan
3Kobe University, 1-1, Rokkodai, Nada, Kobe 657-8501, Japan
Correspondence to: W. Miyake (miyake@crl.go.jp)
Abstract. The dayside cusp/cleft
region is known as a major source of upflowing ionospheric ions to the
magnetosphere. Since the ions are supposed to be energized by an input of
energy from the dayside magnetospheric boundary region, we examined the
possible influence of the interplanetary conditions on dayside ion beams and
conics observed by the polar-orbiting Exos-D (Akebono) satellite. We found that
both the solar wind velocity and density, as well as IMF By and Bz , affect the
occurrence frequency of ion conics. The energy of ion conics also depends on
the solar wind velocity, IMF By and Bz . The ion beams around the local noon
are not significantly controlled by the interplanetary conditions. The results
reveal that ion convection, as well as the energy source, is important to
understand the production of dayside ion conics while that of ion beams
basically reflects the intensity of local field-aligned currents.
Key words. Ionosphere (particle
acceleration) – magnetospheric physics (magnetopause, cusp, and boundary
layers; magnetosphere ionosphere interaction)
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