Irregularities in the rate of generation of giant pulses from the Crab pulsar observed at 111 MHz

Abstract: We present analysis of the rate of giant radio pulses (GPs) emission from the Crab pulsar (B0531+21). Results of our 9 years daily observations with the Large Phased Array radio telescope of Pushchino Radio Astronomy Observatory at 111 MHz were used. Limited sample of 8753 strong individual pulses in 2004 observational sessions was further analysed. It was shown that the observed monthly averaged rate of GPs emission was highly unstable during the entire span of observations and changes by about two orders of magnitude for high-energy pulses. Data were further analysed to search for the possible connection between pulsar glitches and the process of GP emission. We have found a significant increase in the rate of emission of high-energy GPs after MJD 58064, when the largest glitch ever observed in the Crab pulsar was happened. Although considerable changes in GPs emission rate could have been caused by the propagation effects in the nebula itself, we have found that the pulsar had demonstrated high degree of intrinsic irregularity of high-energy pulses emission over long time intervals.