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Time-dependent 2.2-MeV and 0.5-MeV lines from solar flares

Journal Article · · Astrophys. J., v. 202, no. 2, pp. 532-542
DOI:https://doi.org/10.1086/154003· OSTI ID:4057385
The time dependences of the 2.2- 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. The time lag between the nuclear reactions and the formation of these two lines is caused by capture of the neutrons and subsequent deceleration of the positrons and decay of the radioactive nuclei. Our main results are that the calculation is consistent with the observed rise fo the 2.2-MeV line on August 4, and it does not require different time dependences for the accelerated protons and high-energy 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. (AIP)
Research Organization:
NASA-Goddard Space Flight Center, Greenbelt, Maryland
Sponsoring Organization:
USDOE
NSA Number:
NSA-33-024086
OSTI ID:
4057385
Journal Information:
Astrophys. J., v. 202, no. 2, pp. 532-542, Journal Name: Astrophys. J., v. 202, no. 2, pp. 532-542; ISSN ASJOA
Country of Publication:
United States
Language:
English