Multi-satellite study of the excitation of Pc3 and Pc4-5 ULF waves and their penetration across the plasmapause during the 2003 Halloween superstorm

Annales Geophysicae. 2015;33:1237-1252 DOI 10.5194/angeo-33-1237-2015

 

Journal Homepage

Journal Title: Annales Geophysicae

ISSN: 0992-7689 (Print); 1432-0576 (Online)

Publisher: Copernicus Publications

Society/Institution: European Geosciences Union (EGU)

LCC Subject Category: Science: Physics: Geophysics. Cosmic physics

Country of publisher: Germany

Language of fulltext: English

Full-text formats available: PDF, XML

 

AUTHORS

G. Balasis (Institute for Astronomy, Astrophysics, Space Applications and Remote Sensing, National Observatory of Athens, Athens, Greece)
I. A. Daglis (Section of Astrophysics, Astronomy and Mechanics, Department of Physics, University of Athens, Athens, Greece)
I. R. Mann (Department of Physics, University of Alberta, Edmonton, Alberta, Canada)
C. Papadimitriou (Institute for Astronomy, Astrophysics, Space Applications and Remote Sensing, National Observatory of Athens, Athens, Greece)
C. Papadimitriou (Section of Astrophysics, Astronomy and Mechanics, Department of Physics, University of Athens, Athens, Greece)
E. Zesta (Geospace Physics Laboratory, Heliophysics Science Division, NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA)
M. Georgiou (Section of Astrophysics, Astronomy and Mechanics, Department of Physics, University of Athens, Athens, Greece)
R. Haagmans (European Space Research and Technology Centre, European Space Agency, Noordwijk, the Netherlands)
K. Tsinganos (Section of Astrophysics, Astronomy and Mechanics, Department of Physics, University of Athens, Athens, Greece)

EDITORIAL INFORMATION

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Time From Submission to Publication: 28 weeks

 

Abstract | Full Text

We use multi-satellite and ground-based magnetic data to investigate the concurrent characteristics of Pc3 (22–100 mHz) and Pc4-5 (1–22 mHz) ultra-low-frequency (ULF) waves on the 31 October 2003 during the Halloween magnetic superstorm. ULF waves are seen in the Earth's magnetosphere, topside ionosphere, and Earth's surface, enabling an examination of their propagation characteristics. We employ a time–frequency analysis technique and examine data from when the Cluster and CHAMP spacecraft were in good local time (LT) conjunction near the dayside noon–midnight meridian. We find clear evidence of the excitation of both Pc3 and Pc4-5 waves, but more significantly we find a clear separation in the L shell of occurrence of the Pc4-5 and Pc3 waves in the equatorial inner magnetosphere, separated by the density gradients at the plasmapause boundary layer. A key finding of the wavelet spectral analysis of data collected from the Geotail, Cluster, and CHAMP spacecraft and the CARISMA and GIMA magnetometer networks was a remarkably clear transition of the waves' frequency into dominance in a higher-frequency regime within the Pc3 range. Analysis of the local field line resonance frequency suggests that the separation of the Pc4-5 and Pc3 emissions across the plasmapause is consistent with the structure of the inhomogeneous field line resonance Alfvén continuum. The Pc4-5 waves are consistent with direct excitation by the solar wind in the plasma trough, as well as Pc3 wave absorption in the plasmasphere following excitation by upstream waves originating at the bow shock in the local noon sector. However, despite good solar wind coverage, our study was not able to unambiguously identify a clear explanation for the sharp universal time (UT) onset of the discrete frequency and large-amplitude Pc3 wave power.