Radio spectrum of micropulses from pulsar PSR 0950+08

The microstructure in the radio pulses from PSR 0950+08 has been studied over both wide and narrow frequency ranges. The micropulses characterized by 0.17 ms duration are broad-band, exhibiting 50 percent correlation between 111 and 318 MHz. Over 125 kHz centered on 111 MHz the dynamic spectra of individual micropulses show deep modulation over intervals equal to the reciprocal of the pulse durations. These results are discussed in the light of the coherent radiation which is necessary to explain the large apparent brightness temperature seen in pulsars. It is concluded that the micropulses result from the incoherent addition of many particle bunches, each one emitting coherently over a wide bandwidth