Remote sensing of low-energy SEPs via charge exchange

Hudson, H.S. and MacKinnon, A. L. and Badnell, Nigel; Zank, Gary P. and Borovsky, Joe and Bruno, Roberto and Cirtain, Jonathan and Cranmer, Steve and Elliott, Heather and Giacalone, Joe and Gonzalez, Walter and Li, Gang and Marsh, Eckart and Moebius, Ebehard and Pogorelov, Nick and Spann, Jim and Verkhoglyadova, Olga, eds. (2013) Remote sensing of low-energy SEPs via charge exchange. In: Solar Wind 13. AIP Conference Proceedings . AIP Publishing, USA, pp. 19-21. ISBN 9780735411630 (

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Charge-exchange reactions at high energies provide new channels for the remote sensing of solar high-energy particles, as demonstrated by the recent detection of 1.8-5 MeV hydrogen atoms from a solar flare [1]. Orrall and Zirker [2] had earlier proposed the detection of low-energy protons via charge-exchange atomic reactions in the solar atmosphere, leading in the simplest case to extended red-wing emission in the Lyman-alpha line. We discuss the analogous process for the He II 304 Å line (for alpha particles) and also assess the feasibility of the analogous process in the solar wind, whereby ambient He and (C, N, O) ions allow low-energy alpha particles to undergo resonant charge exchange in the ambient corona and thereby produce 304 Å wing emission close to the acceleration region.