A JOINT ANALYSIS OF HIGH-ENERGY NEUTRONS AND NEUTRON-DECAY PROTONS FROM A FLARE

A joint analysis of neutron monitor and GOES data is performed to stud y the production of high-energy neutrons at the Sun. The main objects of the research are the spectrum of >50 MeV neutrons and a possible sp ectrum of primary (interacting) protons which produced those neutrons during the major 1990 May 24 solar flare. Different possible scenarios of the neutron production are presented. The high magnitude of the 19 90 May 24 neutron event provided an opportunity to detect neutron deca y protons of higher energies than ever before. The compare predictions of the proposed models of neutron production with the observations of protons on board GOES 6 and 7. It is shown that the 'precursor' in hi gh-energy GOES channels observed during 20:55-21:09 UT can be naturall y explained as originating from decay of neutrons in the interplanetar y medium. The ratio of counting rates observed in different GOES chann els can ensure the selection of the model parameters. The set of exper imental data can be explained in the framework of a scenario which ass umes the existence of two components of interacting protons in the fla re. A hard spectrum component (the first component) generates neutrons during a short time while the intel action of the second (soft spectr um) component lasts longer. Alternative scenarios are found to be of l esser likelihood. The intensity-time profile of neutron-decay protons as predicted in the framework of the two-component exponential model o f neutron production (Kocharov et al., 1994a) is in an agreement with the proton profiles observed on board GOES. We compare the deduced cha racteristics of interacting high-energy protons with the characteristi cs of protons escaping into the interplanetary medium. It is shown tha t, in the 100-1000 MeV range, the spectrum of the second component of interacting protons was close to the spectrum of the prompt component of interplanetary protons. However, it is most likely that, at similar to 300 MeV, the interacting proton spectrum was slightly softer than the spectrum of interplanetary protons. An analysis of gamma-ray emiss ion is required to deduce the spectrum of interacting protons below 10 0 MeV and above 1 GeV.