Complex sentence: The current through the filaments and the inductive ballast is abruptly interrupted, leaving the full line voltage applied between the filaments at the ends of the tube and generating an inductive kick which provides the high voltage needed to start the lamp.
Split into simpler sentences: The current through the filaments is interrupted, leaving the full line voltage applied between the filaments at the ends of the tube. The inductive kick from the interruption of current through the ballast provides the high voltage needed to start the lamp.