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Energetic particle precipitation into the middle atmosphere triggered by a coronal mass ejection

Clilverd, M. A. and Rodger, C. J. and Millan, R. M. and Sample, J. G. and Kokorowski, M. and McCarthy, M. P. and Ulich, T. and Raita, T. and Kavanagh, Andrew J. and Spanswick, E. (2007) Energetic particle precipitation into the middle atmosphere triggered by a coronal mass ejection. Journal of Geophysical Research, 112. A12206. ISSN 0148-0227

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    Abstract

    Precipitation of relativistic electrons into the atmosphere has been suggested as the primary loss mechanism for radiation belt electrons during large geomagnetic storms. Here we investigate the geographical spread of precipitation as a result of the arrival of a coronal mass ejection (CME) on 21 January 2005. In contrast to previous statistical studies we provide one of the first attempts to describe the geographic and temporal variability of energetic particle precipitation on a global scale using an array of instruments. We combine data from subionospheric VLF radio wave receivers, the high-altitude Miniature Spectrometer (MINIS) balloons, riometers, and pulsation magnetometers during the first hour of the event. There were three distinct types of energetic electron precipitation observed, one globally, one on the dayside, and one on the nightside. The most extensively observed form of precipitation was a large burst starting when the CME arrived at the Earth, where electrons from the outer radiation belt were lost to the atmosphere over a large region of the Earth. On the dayside of the Earth (10–15 MLT) the CME produced a further series of precipitation bursts, while on the nightside dusk sector (∼20 MLT) a continuous precipitation event lasting ∼50 min was observed at 2.5 < L < 3.7 along with Pc 1–2 pulsations observed with a ground-based magnetometer. These observations suggest that the generation of energetic electron precipitation at the inner edge of the outer radiation belt from electromagnetic ion cyclotron (EMIC) wave scattering into the loss cone is the most direct evidence to date connecting EMIC activity and energetic precipitation.

    Item Type: Article
    Journal or Publication Title: Journal of Geophysical Research
    Additional Information: Copyright (2007) American Geophysical Union. Further reproduction or electronic distribution is not permitted
    Uncontrolled Keywords: CME ; electron precipitation ; EMIC ; riometer ; VLF DCS-publications-id ; art-882 ; DCS-publications-credits ; iono ; iris ; DCS-publications-personnel-id ; 9
    Subjects: T Technology > T Technology (General)
    Departments: Faculty of Science and Technology > School of Computing & Communications
    Faculty of Science and Technology > Physics
    ID Code: 6704
    Deposited By: ep_importer_dcs
    Deposited On: 21 Apr 2008 12:04
    Refereed?: Yes
    Published?: Published
    Last Modified: 09 Apr 2014 22:12
    Identification Number:
    URI: http://eprints.lancs.ac.uk/id/eprint/6704

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