Abstract
Electrons of ~ 40 keV energy observed at 1 AU are used as tracers to map the emission structure of a large active region, McMath plage 8905, which crossed the visible disk in July–August, 1967.
The acceleration of 10–100 keV electrons is found to be a property of active regions with a certain stage of development, and is signaled by the emission of ≳ 20 keV X-rays. The emission of electrons into the interplanetary medium may be separate from the acceleration of the electrons. Type III radio emission at long wavelengths appears to indicate the escape of the electrons into the interplanetary medium.
The subsequent electron propagation in the interplanetary medium is essentially scatter-free, and the profile of the electron appears to be determined predominantly by transport/storage processes in the solar corona. The emission structure for active region McMath plage 8905 consists of (1) an open cone of ~ 70° extent in solar longitude where electrons have direct access to interplanetary field lines; (2) a cone of propagation of 100° width in solar longitude, surrounding and including the open cone in which impulsive electron events are observed; and (3) an overall ~ 200° extent of solar longitude over which low, non-impulsive fluxes from the active region are observed. A model is presented to account for the observed structure. This type of emission structure may be present in other electron-active regions.
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Lin, R.P. The emission and propagation of ∼40keV solar flare electrons. Sol Phys 15, 453–478 (1970). https://doi.org/10.1007/BF00151852
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DOI: https://doi.org/10.1007/BF00151852