[en] A study of energy dependence in elemental abundances of eight large solar-flare associated particle events reveals a wide range of variation in the Fe(group)/O ratios from event to event. While the energy dependence is consistent in most events with individual element spectra approximately exponentials in rigidity, several events show unusual behavior in the Fe(group)/O ratio due to the existence of several distinct spectral components. These multiple spectral components may imply multiple phases of acceleration or substantial interplanetary shock contamination at low energies at times well before the arrival time of these shocks at 1 AU

[en] It was discovered on Pioneer 10 that the quiet-time intensities of low energy nitrogen and oxygen nuclei are anomalously high compared to the intensity of carbon nuclei. The source of this enhancement is unknown. The sun can be ruled out as the source, however. To elucidate this problem we have studied the charge composition and time variations of quiet-time cosmic rays in the energy range approximately 10-25 MeV/nucleon. The charge composition has been determined by summing data from IMP7 over a period of more than two years and data from IMP8 over a period of one year. A turn-up observed in the Ne spectrum is apparently not solar in origin. Helium and oxygen are observed to have the same percentage solar modulation for a range of x5 in intensity. (orig./BJ)

[en] We have studied amplitude variations of low energy cosmic rays near earth during the last solar minimum. We find that low energy helium displays a larger amplitude of variation than does hydrogen at the same kinetic energy per nucleon. This is despite the fact that the helium has at least twice as high a magnetic rigidity as the hydrogen and possibly four times as high, depending on the helium charge state. We argue that this is evidence for adiabatic energy loss in the solar wind

[en] Hysteresis effects in the modulation of the anomalous helium and the anomalous oxygen have been used to argue that neither is fully ionized. We dispute these interpretations

[en] The intensity of the low energy anomalous helium and oxygen components has been continuously monitored by telescopes on the Pioneer 10 and IMP 7 and 8 spacecraft since 1972. After a period of relatively small temporal changes at earth between 1972 and 1978, during which it was possible to study the radial gradients of these components out to approximately 15 AU, large temporal changes were observed in 1978-1980 associated with the onset of the new solar modulation cycle. During this time period the anomalous He and O intensities at Pioneer 10 have decreased by a factor > 10, however, both anomalous components were still present in the summer of 1980 at approximately 20 AU. At the earth similar large intensity changes have occurred. At pioneer 10 the relative modulation of He nuclei is approximately 1.4x that of O nuclei at the same energy/nuc during this time period

[en] This article presents data from the SAMPEX satellite of trapped heavy ions in the ionosphere, with energies greater than 15 MeV/nucleon. The data shows trapped He, N, O, and Ne. These ions are thought to be of cosmic ray origin, and to have been trapped by the geomagnetic field due to the loss of electrons due to scattering events in the upper atmosphere

[en] Recent observations using the GSFC-UNH cosmic ray telescope aboard the Pioneer 10 space probe have revealed an anomalous spectrum of nitrogen and oxygen nuclei relative to other nuclei such as carbon in the quiet time cosmic radiation below about 40 MeV/nuc. We have extended these observations with additional data from Pioneer 10 and considerable new data from an identical telescope aboard Pioneer 11. In addition to the enhancement of nitrogen and oxygen nuclei observed earlier we now observe the intensity of neon to be enhanced as well. The spectra of boron, magnesium and silicon appear to be similar to that of carbon. Within the accuracy of our measurements the enhancement factors for nitrogen, oxygen and neon are all approximately 10 relative to carbon at 10 MeV/nuc and the spectra of the enhanced nuclei can be represented by the form dj/dE approximately Esup(-2 x 6 +- 0.2) in the energy range 10-30 MeV/nuc. We will report details on the isotopic composition, solar modulation, and radial gradient of these nuclei. (orig.)

[en] New observations of >15 MeV/nuc trapped heavy ions with Z ≥ 2 have been made by the S AMPEX spacecraft in low polar orbit. The composition of these ions, which are located primarily around L = 2, is dominated by He, N, O, and Ne. The N, O, and Ne ions are apparently trapped ''anomalous cosmic rays,'' while the origin of the trapped He flux is presently uncertain. These ions can affect the rate of single-event upsets (SEUs) in spacecraft hardware

[en] Anomalous cosmic rays (ACRs) provide a sensitive probe of the access of energetic particles to the inner heliosphere, varying in intensity by more than two orders of magnitude during the course of the solar cycle. New data which are becoming available from the Advanced Composition Explorer (ACE) can provide a detailed record of ACR intensity and spectral changes on short (∼1 day) time scales during the approach to solar maximum, which will help address issues of ACR modulation and transport. The elemental and isotopic composition of ACRs provides important information on the source or sources of these particles, while their ionic charge state composition and its energy dependence serves as a diagnostic of their acceleration time scale. We review measurements of the ACR elemental, isotopic, and charge state composition and spectra as determined at 1 AU by SAMPEX, ACE, Wind, and other spacecraft. These results are important input to models of the acceleration, modulation, and transport of ACRs

[en] The abundances of elements from helium to iron have been measured in more than a dozen moderate to large solar energetic particle (SEP) events using the Solar Isotope Spectrometer (SIS) on-board the Advanced Composition Explorer (ACE). Time variations within some of these events and from event to event have been reported previously. This paper presents an analysis of the event of 6 May 1998, for which relatively time-independent abundance ratios are found. This event has been considered to be an example of an impulsive event, a gradual event, and as a hybrid of the two. Difficulties with classifying this event are discussed