Structure of energetic radiation bursts observed during winter thunderstorms
Abstract
Two types of radiation burst from the difference of the duration, "long burst" and "short burst", are observed during thunderstorm activities. We made it clear that there is a feature different from a signal pulse incident on a radiation detector as a result of the in-depth investigation of those pulses. For the short burst by which duration was thought to continue within 1 second, photons with the energy of 0.5MeV seen as annihilation gamma-rays of a positron emitted first as a start of the short burst, and some bundle of several MeV photons which are followed and continues for about several milliseconds occurs discretely. About the long burst to last for several minutes, several MeV photons were emitted continually for several 100 seconds, and the event that the number of the photons decreased rapidly afterwards, and return to the background level was observed. The long burst do not have a fine structure in such a time interval and the energy distribution of the short burst during the emission of energetic photons. Moreover, from an earlier than about 100 seconds long burst will occur, even though the counting rate of the detector is almost no fluctuate, events whose energy varies significantly were observed. Then, after the end long burst, the variation of the energy was found to return to the original level. Prior to occurrence of the long burst, the electric field structures in the path which the radiation comes through, suggesting that energy distribution of the radiation reaching the ground considerably varies. In the AGU meeting, we will report on the result of the measurement.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2016
- Bibcode:
- 2016AGUFMAE33A0432T
- Keywords:
-
- 3304 Atmospheric electricity;
- ATMOSPHERIC PROCESSESDE: 3324 Lightning;
- ATMOSPHERIC PROCESSES