The Astrophysical Journal · 1968 · 45 citations · 0 references
Natural SciencesPhysicsNuclear PhysicsParticle PhysicsSpectroscopyNuclear AstrophysicsSolar Energetic ParticlesSolar PhysicsEnergy Spectra MeasurementSolar Energetic Particle EventsSolar Particle EventsSolar Proton Events
The study measured the proton energy spectrum from 3 to 100 MeV and obtained helium and heavier nuclei spectra over a narrower range. The event is the fifth with detected heavy nuclei, and the measured abundances of helium, light, medium, and heavy nuclei (14–35 MeV/n) match previous events and solar photosphere values, supporting a multicharged nuclear composition; the hydrogen‑to‑helium ratio is 16 ± 2, and the data rule out a simple diffusion propagation model. Published in The Astrophysical Journal (Oct 1968, DOI 10.1086/149759) by Durgaprasad et al., reporting heavy nuclei detection in the 1966 solar‑particle event.
view Abstract Citations (43) References (23) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Nuclear-Charge Spectra and Energy Spectra in the September 2, 1966, Solar-Particle Event Durgaprasad, N. ; Fichtel, C. E. ; Guss, D. E. ; Reames, D. V. Abstract Heavy nuclei (Z »= 3) were detected in the September 2, 1966, solar-particle event. This brings to five the number of events in which these particles have been detected. The proton energy spectrum was measured down to energies as low as 3 MeV and up to energies as high as 100 MeV, with measurements on the helium and heavier nuclei covering a more restricted range. The relative abundances of helium, light (3 «= Z «= 5), medium (6 «= Z «= 9), and heavier nuclei obtained in this experiment in the energy range from about 14 to 35 MeV nucleon' agree with those measured in previous solar-particle events at higher energies and hence with those of the solar photosphere. This result strengthens the concept of a multicharged nuclear composition, which is a characteristic of solar-particle events. Use of the recent solar spectroscopic data and the ratio of helium to medium nuclei observed in the solar cosmic rays results in a hydrogen-to-helium ratio of 16 ± 2. An examination of the relative abundances of protons and medium nuclei shows that the propagation of solar particles in this event cannot be described by a simple diffusion model with a diffusion coefficient proportional to j3 or 13R Publication: The Astrophysical Journal Pub Date: October 1968 DOI: 10.1086/149759 Bibcode: 1968ApJ...154..307D full text sources ADS |