Multiradar observations of the polar tongue of ionization
Name
TOI_JGR05.pdf
Description
article as published in JGR Space Physics
Size
1.49 MB
Format
Adobe PDF
Checksum (MD5)
9a74a7598154d5ce92dc93fb8cb80ff5
Author(s)
McCready, M.
van Eyken, A.
Barnes, R. J.
Greenwald, R. A.
Rich, F. J.
Foster, John C
Coster, Anthea J
Erickson, Philip J
Holt, John M
Lind, Frank David
Date Issued
September 2005
Journal
Journal of Geophysical Research: Space Physics
Publisher
American Geophysical Union (AGU)
Citation
Foster, J. C. et al. “Multiradar Observations of the Polar Tongue of Ionization.” Journal of Geophysical Research: Space Physics 110, A9 (September 2005): S31 © 2005 American Geophysical Union
Version
Final published version
Abstract
[1] We present a global view of large‐scale ionospheric disturbances during the main phase of a major geomagnetic storm. We find that the low‐latitude, auroral, and polar latitude regions are coupled by processes that redistribute thermal plasma throughout the system. For the large geomagnetic storm on 20 November 2003, we examine data from the high‐latitude incoherent scatter radars at Millstone Hill, Sondrestrom, and EISCAT Tromso, with SuperDARN HF radar observations of the high‐latitude convection pattern and DMSP observations of in situ plasma parameters in the topside ionosphere. We combine these with north polar maps of stormtime plumes of enhanced total electron content (TEC) derived from a network of GPS receivers. The polar tongue of ionization (TOI) is seen to be a continuous stream of dense cold plasma entrained in the global convection pattern. The dayside source of the TOI is the plume of storm enhanced density (SED) transported from low latitudes in the postnoon sector by the subauroral disturbance electric field. Convection carries this material through the dayside cusp and across the polar cap to the nightside where the auroral F region is significantly enhanced by the SED material. The three incoherent scatter radars provided full altitude profiles of plasma density, temperatures, and vertical velocity as the TOI plume crossed their different positions, under the cusp, in the center of the polar cap, and at the midnight oval/polar cap boundary. Greatly elevated F peak density (>1.5E12 m[superscript −3]) and low electron and ion temperatures (∼2500 K at the F peak altitude) characterize the SED/TOI plasma observed at all points along its high‐latitude trajectory. For this event, SED/TOI F region TEC (150–1000 km) was ∼50 TECu both in the cusp and in the center of the polar cap. Large, upward directed fluxes of O+ (>1.E14 m[superscript −2] s[superscript −1]) were observed in the topside ionosphere from the SED/TOI plume within the cusp.
MIT Department
Haystack Observatory
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Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use.
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DOI of Published Version
https://doi.org/10.1029/2004JA010928
