Possible accretion instabilities on magnetized rotating neutron stars

The high energy particles emitted by a pulsar prevent the accretion of the interstellar matter onto the star. However, during the life of a pulsar the energy output decreases and after elapsing of critical timet_cr the pulsar mechanism is obviously inhibited and matter may penetrate through the radius of capturer_a. It is proposed that a possible accumulation of this matter in the regionrr_c, wherer_c is the corotational radius, is followed by a sudden fall onto the stellar surface. Short bursts of high energy photons may be expected as a result. A possible explanation of recently observed gamma-ray bursts by this mechanism is discussed.