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Proceedings Paper

Forecasting the arrival of fast coronal-mass ejecta at Earth by the detection of 2-20keV neutral atoms
Author(s): Ke Chiang Hsieh; K.-L. Shih; David J. McComas; Shi Tsan Wu; Caroline Wu
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Paper Abstract

Studies have show that Earth passages of fast coronal mass ejections (CMEs) trigger geomagnetic storms. Early identification of fast Earth-directed CME can help provide storm warnings, but detection of such by coronagraphs is extremely difficult. We suggest that energetic hydrogen atoms (EHA) between 2 and 10 keV produced during the transit phase of an Earth-directed CME by recombination between protons and electrons in the CME can travel ahead of the CME and act as harbingers of a magnetic storm. This forecasting scheme should work if enough EHA are produced, because while CMEs decelerate continuously after their ejection, the EHA fluxes produced in the initial phase of fast CMEs propagate at their initial high speeds (> 1 X 103 km s-1). Model simulations support this proposed mechanism. A coarse measurement of the CME-produced ENA at 1 AU could provide storm warning hours in advance, and finer measurements could yield detailed information on the likely geomagnetic effectiveness of a CME, as well as the evolution and propagation of CME between the Sun and Earth.

Paper Details

Date Published: 1 June 1992
PDF: 7 pages
Proc. SPIE 1744, Instrumentation for Magnetospheric Imagery, (1 June 1992); doi: 10.1117/12.60581
Show Author Affiliations
Ke Chiang Hsieh, Univ. of Arizona (United States)
K.-L. Shih, Univ. of Arizona (United States)
David J. McComas, Los Alamos National Lab. (United States)
Shi Tsan Wu, Univ. of Alabama in Huntsville (United States)
Caroline Wu, Univ. of Alabama in Huntsville (United States)

Published in SPIE Proceedings Vol. 1744:
Instrumentation for Magnetospheric Imagery
Supriya Chakrabarti, Editor(s)

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