Laser produced gamma-photons can make an important impact on applied and
fundamental physics that require high gamma-photon yield and strong
collimation. We propose addition of a constant magnetic field to the
laser-solid interaction to obtain the aforementioned desired gamma-photon
properties. The gamma-ray flash spatial and spectral characteristics are
obtained via quantum electrodynamics particle-in-cell simulations. When the
constant magnetic field aligns with the laser magnetic field then the
gamma-ray emission is significantly enhanced. Moreover, the gammaa-photon
spatial distribution becomes collimated, approximately in the form of a disk.Comment: 5 pages, 5 figure