We study the dynamic and radiative efficiency of conversion of
kinetic-to-thermal/magnetic energy by internal shocks in relativistic
magnetized outflows. A parameter study of a large number of collisions of
cylindrical shells is performed. We explore how, while keeping the total flow
luminosity constant, the variable fluid magnetization influences the efficiency
and find that the interaction of shells in a mildly magnetized jet yields
higher dynamic, but lower radiative efficiency than in a non-magnetized flow. A
multi-wavelength radiative signature of different shell magnetization is
computed assuming that relativistic particles are accelerated at internal
shocks.Comment: 4 pages, 2 figures, proceedings of the meeting "HEPRO III: High
Energy Phenomena in Relativistic Outflows" (Barcelona, June 2011), fixed the
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