Anomalous cosmic ray composition from ACE

During solar quiet periods, the Solar Isotope Spectrometer (SIS) on the Advanced Composition Explorer (ACE) measures the composition and energy spectra of anomalous cosmic rays (ACRs) with energies >8 MeV/nucleon in interplanetary space at 1 AU. In particular, the spectra of individual isotopes for the ACR elements N, O, and Ne are studied with SIS. Intensity enhancements are found in low energy 18O and 22Ne, with relative abundances of ^(18)O/^(16)O ~ 0.002 and ^(22)Ne/^(20)Ne ~ 0.1. The neon abundance ratio appears more similar to that found in the solar wind than in meteorites and is far below that determined for the galactic cosmic ray (GCR) source, indicating that GCRs contain material from sources other than just the local interstellar medium

The Ionic Charge State Composition at High Energies in Large Solar Energetic Particle Events in Solar Cycle 23

The ionic charge states of solar energetic particles (SEPs) depend upon the temperature of the source material and on the environment encountered during acceleration and transport during which electron stripping may occur. Measurements of SEP charge states at relatively high energies (≳15 MeV/nucleon) are possible with the Mass Spectrometer Telescope (MAST) on the Solar, Anomalous, and Magnetospheric Particle Explorer satellite by using the Earth's magnetic field as a particle rigidity filter. Using MAST data, we have determined ionic charge states of Fe and other elements in several of the largest SEP events of solar cycle 23. The charge states appear to be correlated with elemental abundances, with high charge states (~20 for Fe) for all elements in large Fe-rich events. We review the geomagnetic filter technique and summarize the results from MAST to date, with particular emphasis on new measurements in the very large 14 July 2000 SEP event. We compare the charge states determined by MAST with other measurements and with those expected from equilibrium calculations

Composition Measurements from ISEE-3: Fluorine through Calcium

Spacecraft measurements are reported of the elemental composition of galactic cosmic rays with 9 ≤ Z ≤ 5 ~20 at energies ~220 MeV /nucleon. In addition, for the elements with 16 ≤ Z ≤ 20 isotopic composition results are reported. The measured composition is found to be in generally good agreement with that expected from a propagated solar-like source

Anomalous Cosmic Rays: A Sample of Interstellar Matter

Anomalous cosmic rays are a sample of the neutral interstellar medium that has been accelerated to energies of ~1 to 50 MeV/nuc. A comparison of ^(22)Ne/^(20)Ne measurements from various sources implies that galactic cosmic rays with energies > 100 MeV/nuc are not simply an accelerated sample of the local interstellar medium

Geomagnetically Trapped Anomalous Cosmic Rays at Solar Minimum

The geomagnetically trapped a...r10malous cosmic rays have been monitored continuously by instrumentation on the SAMPEX satellite since its launch in mid-1992. With the approach of solar mimmum the intensity has been increasing along with that of the interplanetary anomalous cosmic ray source. We compare the time variations of the two components using data from the MAST instrument: describe improved measurements of the spatiaJ distribution of the trapped component, and discuss implications for the trapping and lifetime of the trapped component

Evolution of suprathermal seed particle and solar energetic particle abundances

We report on a survey of the composition of solar-wind suprathermal tails and solar energetic particles (SEPs) including data from 1998 to 2010, with a focus on 2007 to 2010. The start of solar cycle 24 included several SEP events that were unusually He-poor. We conclude that these He-poor events are more likely related to Q/M-dependent spectral variations than to seed-particle composition changes. We also find that the quiet-time suprathermal Fe/O ratio during the 2008-2009 solar-minimum was dramatically lower (Fe/O ≤ 0.01) than earlier due in part to very low solar activity, but also suggesting contributions from an oxygen-rich source of suprathermal ions of unknown origin

Elemental and isotopic fractionation in 3He-rich solar energetic particle events

Using data from the Solar Isotope Spectrometer (SIS) on the Advanced Composition Explorer (ACE) mission, heavy ion composition measurements have been made in 26^3He-rich solar energetic particle (SEP) events that occurred between 1998 and 2004. Relative abundances of 13 elements from C through Ni have been investigated, as have the isotopic compositions of the elements Ne and Mg. We find a general tendency for the abundances to follow trends similar to those found in gradual SEP events, in which fractionation can be represented in the form of a power-law in Q/M. However several deviations from this pattern are noted that may provide useful diagnostics of the acceleration process occurring in solar flares

The Space Physics Data System - Cosmic and Heliospheric Nodes

The Space Physics Data System (SPDS) is a community- driven network of information sources, linked and interfaced by World Wide Web software. The SPDS coordinators are community representatives to the NASA Space Physics Division, who are soliciting additional Web nodes, trying to keep the nodes organized, and soliciting information/suggestions about older data in danger of loss. Here we present a guide to data in Cosmic and Heliospheric nodes of the SPDS. New contributions to this system are being solicited and some funds may be available to assist with their development