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At least 55 records · Page 3
All sourcesNASA NTRSDOE OSTI
NASA NTRS1975

Heavy solar cosmic rays in the January 25, 1971 solar flare

A detailed study of the charge composition of heavy solar cosmic rays measured in the January 25, 1971 solar flare including differential fluxes for the even-charged nuclei from carbon through argon is presented. The measurements are obtained for varying energy intervals for each nuclear species in the energy range from 10 to 35 MeV per nucleon. In addition, abundances relative to oxygen are computed for all the above nuclei in the single energy interval from 15 to 25 MeV per nucleon. This interval contains measurements for all of the species and as a result requires no spectral extrapolations. An upper limit for the abundance of calcium nuclei is also presented. These measurements, when combined with other experimental results, enable the energy dependence of abundance measurements as a function of nuclear charge to be discussed. It is seen that at energies above about 10 MeV per nucleon, the variations of abundance ratios are limited to about a factor of 3 from flare to flare, in spite of large variations in other characteristics of these solar events.

Pellerin, C. J., Jr.↗
NASA NTRS1973

Variations of the relative abundances of He, (C,N,O) and Fe-group nuclei in solar cosmic rays and their relationship to solar particle acceleration

Measurements of the flux of helium nuclei in the 24 January 1971 event and of helium and (C,N,O) nuclei in the 1 September 1971 event are combined with previous measurements to obtain the relative abundances of helium, (C,N,O), and Fe-group nuclei in these events. These data are then summarized together with previously reported results to show that, even when the same detector system using a dE/dx plus range technique is used, differences in the He/(C,N,O) value in the same energy/nucleon interval are observed in solar cosmic ray events. Further, when the He/(C,N,O) value is lower the He/(Fe-group nuclei) value is also systematically lower in these large events. When solar particle acceleration theory is analyzed, it is seen that the results suggest that, for large events, Coulomb energy loss probably does not play a major role in determining solar particle composition at higher energies (10 MeV). The variations in multicharged nuclei composition are more likely due to partial ionization during the acceleration phase.

Bertsch, D. L.↗
NASA NTRS1973

The isotopes of H and He in solar cosmic rays

The isotopic composition of H and He in solar cosmic rays was studied with the solar galactic cosmic ray experiment on the Orbiting Geophysical Observatory, OGO-6. Averaging over 20 days of data from seven flare events during 1969, the ratios He-3/-He-4 = 0.10 + or - 0.02, D/H (76) .0003 and T/H (76) .0001 in the 4 to 5 MeV/nucleon energy range were obtained. In addition, large variations were found in the relative abundance of He-3 from event of event, with a maximum ratio of He-3/He-4 = 0.26 + or - 0.08 observed on October 14 and 15, 1969. The relative abundance of He-3 and D during this event does not seem to be consistent with existing calculations of the nuclear interaction orgin of these isotopes.

Garrard, T. L.↗
NASA NTRS1963

SOLAR COSMIC RAYS

Study of propagation, energy spectra, and occurrence of solar cosmic rays

COSMIC RADIATION↗
NASA NTRS1980

A survey of solar cosmic ray composition 1974-1978

Data on solar particle composition from the Goddard experiment on IMP 8 now spans a period of five years. During this time, detailed abundances and spectra have been obtained for elements through the Fe group and isotopic abundances have been obtained for H and He from a number of the largest flare-associated solar particle events. In the energy range 6.7-15 MeV/nucleon, a systematic enhancement of solar cosmic ray over solar photospheric Na, Mg, Al and Si abundances relative to oxygen is shown to exist in all these large flare events. An additional enhancement of abundances in the elements beyond carbon relative to oxygen that is correlated with atomic charge (or mass) occurs in certain events and produces a variability in Fe/O greater than a factor of 10. Summed over these eight large flares, the Be/O and B/O ratios are shown to be less than 0.0002 and Li/O to be less than 0.001 between 4.2 and 15 MeV/nucleon.

Mcguire, R. E.↗
NASA NTRS1969

Galactic and solar cosmic rays

Multiple parameter analysis of galactic and solar cosmic rays for chemical composition and charge distribution

Mc Donald, F. B.↗