Complex sentence: At this moment of blitzar formation, a portion of the pulsar magnetic field outside the black hole is cut off from its suddenly vanished source and is instantly transformed into a sudden burst of wide spectrum radio energy.
Split into simpler sentences: At this moment of blitzar formation, part of the pulsar's magnetic field outside the black hole is suddenly cut off from its vanished source. This magnetic energy is instantly transformed into a burst of wide spectrum radio energy.