Abstract
We report a 511-keV photon flux enhancement that was observed inside a thundercloud and is a result of positron annihilation. The observation was made with the In-flight Lightning Damage Assessment System (ILDAS) on board of an A340 test aircraft. The aircraft was intentionally flying through a thunderstorm at 12-km altitude over Northern Australia in January 2016. Two gamma ray detectors showed a significant count rate increase synchronously with fast electromagnetic field variations registered by an on-board antenna. A sequence of 10 gamma ray enhancements was detected, each lasted for about 1 s. Their spectrum mainly consists of 511-keV photons and their Compton component. The local electric activity during the emission was identified as a series of static discharges of the aircraft. A full-scale Geant4 model of the aircraft was created to estimate the emission area. Monte Carlo simulation indicated that the positrons annihilated in direct vicinity or in the aircraft body.
| Original language | English |
|---|---|
| Pages (from-to) | 8074-8090 |
| Number of pages | 17 |
| Journal | Journal of Geophysical Research. D, Atmospheres |
| Volume | 123 |
| Issue number | 15 |
| DOIs | |
| Publication status | Published - 16 Aug 2018 |
Funding
This work was supported by the European Research Council under the European Union’s Seventh Framework Program(FP7/2007-2013)/ERC grant agreement 320839 and the Research Council of Norway under contracts 208028/F50 and 223252/F50 (CoE). Authors appreciate scientific discussions on different hypotheses with Nikolai Lehtinen, Andrey Mezentsev, and Georgi Genov from University of Bergen. The photon and E-field data used in this paper were uploaded in the supporting information and also available on request ([email protected]).
Keywords
- annihilation
- gamma ray glow
- lightning
- positron
- X-rays