  The computation of radiative energy loss in a finite size QCD medium with
dynamical constituents is a key ingredient for obtaining reliable predictions
for jet quenching in ultra-relativistic heavy ion collisions. It was previously
shown that energy loss in dynamical QCD medium is significantly higher compared
to static QCD medium. To understand this difference, we here analyze magnetic
and electric contributions to energy loss in dynamical QCD medium. We find that
the significantly higher energy loss in the dynamical case is entirely due to
appearance of magnetic contribution in the dynamical medium. While for
asymptotically high energies, the energy loss in static and dynamical medium
approach the same value, we find that the physical origin of the energy loss in
these two cases is different.
