1 June 1992 Forecasting the arrival of fast coronal-mass ejecta at Earth by the detection of 2-20keV neutral atoms
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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.
© (1992) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Ke Chiang Hsieh, K.-L. Shih, David J. McComas, Shi Tsan Wu, 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); doi: 10.1117/12.60581; https://doi.org/10.1117/12.60581


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