Accession Number : ADA018739

Title :   Evaluation of a Prediction Technique for Low Energy Solar Particle Events.

Descriptive Note : Final rept. 2 Oct 72-30 Jun 75,


Personal Author(s) : Roelof,Edmond C. ; Gold,Robert E.

Report Date : 15 SEP 1975

Pagination or Media Count : 52

Abstract : A technique has been developed for the prediction of low energy solar charged particle fluxes near 1 AU. It is based on comprehensive analysis of solar and interplanetary plasma, magnetic field and energetic particle observations. Although analyses have been carried out for periods in 1964-5, 1968-9, 1972 and 1974, a particularly detailed study has been done of the period May-November, 1967 when there was extensive and near-continuous multi-spacecraft data coverage near Earth and in deep space. The prediction technique has been tested on this latter period and the results are satisfactory for the larger particle events. The results indicate that the inclusion of the effects of coronal magnetic structure on particle injection into the interplanetary medium are as essential as an accurate estimate of the time history of the accelerated particle flux. Quantitative models are used for coronal control (Access Probabilities) and particle acceleration (Flux Production Rules), the former based on the topology of low coronal magnetic neutral lines deduced from H alpha filtergrams, and the latter from solar flare optical and x-ray emission. It is concluded that the major needs for improvement in prediction techniques are more accurate indicators of particle production and active region magnetic field structure, as well as remote sensing of solar wind disturbances by daily monitoring of interplanetary radio scintillations.

Descriptors :   *Solar corona, *Charged particles, *Mathematical prediction, *Solar wind, *Extraterrestrial radio waves, Low energy, Planetary atmospheres, Interplanetary space, Particle trajectories, Magnetic fields, Solar flares, X rays, Radio astronomy, Transport properties, Scintillation counters, Particle flux

Subject Categories : Astrophysics
      Numerical Mathematics
      Nuclear Physics & Elementary Particle Physics

Distribution Statement : APPROVED FOR PUBLIC RELEASE