Relativistic Solar Electrons are observed in conjunction with flares
or coronal mass ejections (CMEs), however their formation mechanisms
seem elusive. The existence of non-thermal electrons in the solar
atmosphere and along the heliospheric field lines is deduced through
emission of electromagnetic waves and via direct in situ satellite
measurements at 1 AU. Their spectral shapes and the relative timing
with respect to imaging and spectrographic observations may identify
potential acceleration sites and processes controlling the formation
of the (delayed with respect to a timing of a flare or initiation of
CME) relativistic electrons. It is conjectured that the delayed
acceleration occurs along the stretched, closed coronal field lines,
when an anisotropic seed population of low-energy electrons is
injected in conjunction with the high frequency coronal radio bursts
behind the large CME, as recorded by radioheliographs. The
energization proceeds due to resonant interaction with oblique
whistler waves, which are excited by the nonisotropic seed electrons.
The flare serves mainly as a time reference for the electromagnetic
emissions, while the CME subsequently opens an access for the
relativistic electrons to the interplanetary medium.
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