Time-dependent 2.2 MeV and 0.5 MeV lines from solar flares
The time dependences of the 2.2 MeV and 0.51 MeV gamma ray lines from solar flares are calculated and the results are compared with observations of the 1972, August 4 and 7 flares. Time lag between the nuclear reactions and the formation of these two lines are caused, respectively, by capture of the neutrons, and by deceleration of the positrons and decay of the radioactive nuclei. Results show that the calculation is consistent with the observed rise of the 2.2 MeV line on August 4, and it does not require different time dependences for the accelerated protons and electrons in the flare region. The above lags can explain the delayed gamma ray emission observed on August 7. Positrons of energies greater than about 10 MeV could be detected in interplanetary space following large solar flares. (auth)
- Research Organization:
- National Aeronautics and Space Administration, Greenbelt, Md. (USA). Goddard Space Flight Center
- NSA Number:
- NSA-33-003815
- OSTI ID:
- 4199542
- Report Number(s):
- N--75-21200; NASA-TM-X--70865; X--660-75-74
- Country of Publication:
- United States
- Language:
- English
Similar Records
Gamma-ray and microwave evidence for two phases of acceleration in solar flares
Formation of the 0. 511 MeV line in solar flares