Estimation of an upper limit for the solar neutron emission during large flares

✍ Scribed by E. Kirsch

• Publisher: Springer
• Year: 1973
• Tongue: English
• Weight: 651 KB
• Volume: 28
• Category: Article
• ISSN: 0038-0938
• DOI: 10.1007/bf00152927

✦ Synopsis

Solar neutron emission during large flares is investigated by using neutron monitor data from the mountain stations Chacaltaya (Bolivia), Mina Aguilar (Argentine), Pic-du-Midi (France) and Jungfraujoch (Switzerland). Registrations from such days on which large flares appeared around the local noon time of the monitor station are superimposed with the time of the optical flare as reference point.

No positive evidence for a solar neutron emission was found with this method.. However, by using an extrapolation of the neutron transport functions given by AlsmiIler and Bouglmer a rough estimation of mean upper limits for the solar neutron flux is possible. The flux limits are compared with Lingenfelter's model calculations.

From the Chacaltaya measurements it follows:

and from Pic-du-Midi measurements:

No ~< 6.7 • 10 3 Ncm-2 s-Z per proton flare, E> 50 MeV, if Po = 125 MV N0~<4 • E>50MeV, if Po--60MV P0 --characteristic rigidity of the producing proton spectrum on the Sun.

The flux limits estimated for some special proton flares are consistent with Lingenfelter's predictions for the acceleration phase but are too small for the slowing down phase. Therefore it is believed that Lingenfelter's assumption of isotropic proton emission from the flare region is not fulfilled.