Forecasting the arrival of fast coronal-mass ejecta at Earth by the detection of 2-20keV neutral atoms

Ke Chiang Hsieh; K.-L. Shih; David J. McComas; Shi Tsan Wu; Caroline Wu

doi:10.1117/12.60581

1 June 1992 Forecasting the arrival of fast coronal-mass ejecta at Earth by the detection of 2-20keV neutral atoms

Ke Chiang Hsieh, K.-L. Shih, David J. McComas, Shi Tsan Wu, Caroline Wu

Proceedings Volume 1744, Instrumentation for Magnetospheric Imagery; (1992) https://doi.org/10.1117/12.60581
Event: San Diego '92, 1992, San Diego, CA, United States

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.

Citation Download Citation

Ke Chiang Hsieh, K.-L. Shih, David J. McComas, Shi Tsan Wu, and Caroline Wu "Forecasting the arrival of fast coronal-mass ejecta at Earth by the detection of 2-20keV neutral atoms", Proc. SPIE 1744, Instrumentation for Magnetospheric Imagery, (1 June 1992); https://doi.org/10.1117/12.60581

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