  Jitter radiation is produced by relativistic electrons moving in turbulent
small-scale magnetic fields such as those produced by streaming Weibel-type
instabilities at collisionless shocks in weakly magnetized media. Here we
present a comprehensive study of the dependence of the jitter radiation spectra
on the properties of, in general, anisotropic magnetic turbulence. We have
obtained that the radiation spectra do reflect, to some extent, properties of
the magnetic field spatial distribution, yet the radiation field is anisotropic
and sensitive to the viewing direction with respect to the field anisotropy
direction. We explore the parameter space of the magnetic field distribution
and its effect on the radiation spectrum. Some important results include: the
presence of the harder-than-synchrotron segment below the peak frequency at
some viewing angles, the presence of the high-frequency power-law tail even for
a monoenergetic distribution of electrons, the dependence of the peak frequency
on the field correlation length rather than the field strength, the strong
correlation of the spectral parameters with the viewing angle. In general, we
have found that even relatively minor changes in the magnetic field properties
can produce very significant effects upon the jitter radiation spectra. We
consider these results to be important for accurate interpretation of prompt
gamma-ray burst spectra and possibly other sources.
