We aim to obtain a consistent description of non-thermal emissions from Abell 2256 and to give a prediction for a gamma-ray emission from this galaxy cluster .
Assuming that a radio relic illuminates a localization of an ongoing merger , and that both radio and non-thermal part of hard X-ray emission are due to electron component of cosmic rays filling the relic , we derived from radio and hard X-ray properties of the relic in A2256 the magnetic field strength and number densities for relativistic electrons and protons .
Due to the interpretation of the radio relic as a structure formed just where a shock front is , we discuss a gamma-ray emission at the cluster periphery .
The estimated strength of the magnetic field in the relic is equal to 0.05 \mu G , while the amplitude of the electron number density varies from 3 \cdot 10 ^ { -4 } to 3 \cdot 10 ^ { -5 } cm ^ { -3 } ( respectively for the relic thickness of 50 to 500 kpc ) .
We got a substantial degree of non-equipartition between cosmic rays and magnetic field in the relic region , where the CR pressure is approaching that of thermal gas .
Our prediction for LOFAR is a synchrotron flux from the relic region of the order of \sim 6 Jy at 60MHz and \sim 10 Jy at 30MHz .
The lower limit of the \gamma -ray flux from the relic region calculated for a hadronic channel is of the order of 10 ^ { -12 } erg cm ^ { -2 } .