  Coronal hard X-ray (HXR) and continuum gamma-ray sources associated with the
impulsive phase of solar flares have been the subject of renewed interest in
recent years. They have been interpreted in terms of thin-target, nonthermal
bremsstrahlung emission. This interpretation has led to rather extreme physical
requirements in some cases. For example, in one case, essentially all of the
electrons in the source must be accelerated to nonthermal energies to account
for the coronal HXR source. In other cases, the extremely hard photon spectra
of the coronal continuum gamma-ray emission suggest that the low energy cutoff
of the electron energy distribution lies in the MeV energy range. Here we
consider the role of inverse Compton scattering (ICS) as an alternate emission
mechanism in both the ultra- and mildly relativistic regimes. It is known that
relativistic electrons are produced during powerful flares; these are capable
of up-scattering soft photospheric photons to HXR and gamma-ray energies.
Previously overlooked is the fact that mildly relativistic electrons, generally
produced in much greater numbers in flares of all sizes, can up-scatter EUV/SXR
photons to HXR energies. We also explore ICS on anisotropic electron
distributions and show that the resulting emission can be significantly
enhanced over an isotropic electron distribution for favorable viewing
geometries. We briefly review results from bremsstrahlung emission and
reconsider circumstances under which nonthermal bremsstrahlung or ICS would be
favored. Finally, we consider a selection of coronal HXR and gamma-ray events
and find that in some cases the ICS is a viable alternative emission mechanism.
