Hundreds of gamma-ray glows were observed during about 60 hours of flight. Here we focus on two intense events that were over 7 times stronger than normal background seen at the level of the plane. Our analysis shows that cosmic ray background electrons were being amplified by more than 5,000 times their original number, involving very likely the 'Relativistic Feedback Discharge' process.

The electrical currents due to the relativistic electrons and ions observed here could be hundreds of times stronger than previously measured (powerful enough to significantly affect how thunderstorms build electrical charge). This high-energy process might compete with regular mechanisms controlling storm electrification (convection and lightning), which could change how severe thunderstorms are understood.