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A possible origin of dayside Pc1 magnetic pulsations observed at high latitudes

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posted on 2020-05-28, 16:01 authored by V Safargaleev, A Serebryanskaya, A Koustov, M Lester, E Pchelkina, A Vasilyev
Induction magnetometer observations of dayside Pc1 activity at Barentsburg (BAB, Spitsbergen archipelago, 78.05°N, 14.12°E) are combined with data from two magnetometers located in Scandinavia and the Kola peninsula. Seven events with very large negative IMF Bz components were considered. For all of the events, the cusp location was expected to be significantly shifted equatorward from the statistical position such that the BAB magnetometer was located well inside the polar cap. The DMSP particle data indicated that the BAB magnetometer was indeed inside the polar cap, whereas other magnetometers were collocated with the ionospheric projections of the cusp, the low-latitude boundary layer or the boundary plasma sheet. Pc1 magnetic pulsations were observed only at BAB. In three cases, for which SuperDARN convection data were available, the Pc1 activity correlated with intervals of large-scale convection reconfiguration, such that the plasma flow crossing the BAB location was associated with newly-reconnected magnetic flux tubes drifting tailward. The convection reconfigurations were in response to a decrease in the IMF By component. We argue that the source of the observed Pc1 pulsations is anisotropic plasma of the depletion layer within the magnetosheath. The plasma anisotropy supports the excitation of electromagnetic ion cyclotron waves that are detectable with a ground-based magnetometer when the flux tubes containing the unstable plasma become connected to the Earth's ionosphere in the course of the dayside reconnection processes.

Funding

We thank A. Voronin and S. Noskov (PGI) forBAB and LOZ data of good quality, and N. Kudryashova (PGI) for assistance in the data processing. V.S. is grateful to M.Yamauchi, H.Nilson and T.Sergienko (IRF, Sweden) for useful discussion. The data of the KIL induction magnetometer were provided by SGO(Finland). The solar wind and IMF data from the WIND satellite were obtained from the CDAWeb ISTP Key Parameter database(data providers are K. Olgivie and R. Lepping of NASA). CUT-LASS is a PPARC facility deployed and operated by the University of Leicester in cooperation with the Finish Meteorlogical Institute,Helsinki and the Institute for Space Physics, Uppsala. The northern hemisphere SuperDARN radars are funded through the research agencies of Canada, France the UK and the USA. We thank the PIs of the radars used here for the use of the data. The LYR and KIL magnetic stations are a part of the IMAGE system. The DMSP particle detectors were designed by D. Hardy of AFRL, and the particle data were obtained from JHU/APL. We thank Dave Hardy, FredRich, and Patrick Newell for making them available. The KAK magnetic data and Dstindex are from the Kyoto World Data Center C-2 in Kyoto, Japan. The work of V.S. was partly supported by Svenska Institutet (VISBI Programm stipend). A.V.K. acknowledges funding from NSERC (Canada).

History

Citation

ANNALES GEOPHYSICAE, 2004, 22 (8), pp. 2997-3008 (12)

Author affiliation

/Organisation/COLLEGE OF SCIENCE AND ENGINEERING/Department of Physics and Astronomy

Version

  • VoR (Version of Record)

Published in

ANNALES GEOPHYSICAE

Volume

22

Issue

8

Pagination

2997-3008 (12)

Publisher

EUROPEAN GEOSCIENCES UNION

issn

0992-7689

Acceptance date

2004-04-20

Copyright date

2004

Language

English