Ground disturbances of the ring, magnetopause, and tail currents on the day the solar wind almost disappeared

V. K Jordanova; C. J Farrugia; J. F Fennell; J. D Scudder

doi:10.1029/2000JA000251

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Ground disturbances of the ring, magnetopause, and tail currents on the day the solar wind almost disappeared

Journal article

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Ground disturbances of the ring, magnetopause, and tail currents on the day the solar wind almost disappeared

V. K Jordanova, C. J Farrugia, J. F Fennell and J. D Scudder

Journal of geophysical research, Vol.106(A11), pp.25529-25540

2001

DOI: 10.1029/2000JA000251

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Abstract

We study ring current dynamics on a day of exceptionally low solar wind density (of ∼0.1 cm-3). Inner magnetospheric measurements of geomagnetic activity show geomagnetic quiet par excellence. On May 11, 1999, the values were |Dst| < 10 nT and Kp = 0+. The field at geostationary orbit was very close to dipolar. We simulate the global evolution of the ring current ion population during this period and compare the effect of the magnetopause, ring, magnetotail, and field-aligned currents on the Dst index. Measured H+, He+, and O+ energy and pitch angle distributions by the Magnetospheric Ion Composition Spectrometer (MICS) and HYDRA instruments on Polar on May 9 are used as initial conditions for our kinetic model. Comparing model results with Polar data on May 11, we find remarkable agreement, proving the applicability of our model for these magnetospheric conditions. We compare modeled H+ and He+ ion distributions with quiet time ring current distributions inferred from statistical studies, and we find that as a general trend, the simulation results have lower values than the statistical patterns. The ground magnetic field disturbances due to the ring and the magnetopause currents decrease quasi-monotonically on May 11, reaching limiting magnitudes of ∼5 and ∼3 nT, respectively. These values are substantially smaller than the ∼20 nT quiet time values obtained from statistical studies. Copyright 2001 by the American Geophysical Union.

Earth, ocean, space

Exact sciences and technology

External geophysics

Geomagnetic observations and data

Physics of the magnetosphere

Details

Title: Subtitle: Ground disturbances of the ring, magnetopause, and tail currents on the day the solar wind almost disappeared
Creators: V. K Jordanova - University of New Hampshire
C. J Farrugia - University of New Hampshire
J. F Fennell - The Aerospace Corporation
J. D Scudder - University of Iowa
Resource Type: Journal article
Publication Details: Journal of geophysical research, Vol.106(A11), pp.25529-25540
DOI: 10.1029/2000JA000251
ISSN: 0148-0227
eISSN: 2156-2202
Publisher: American Geophysical Union
Language: English
Date published: 2001
Academic Unit: Physics and Astronomy
Record Identifier: 9984199946502771

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