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1.
M. E. Wiedenbeck 《Space Science Reviews》2013,176(1-4):35-46
The spectra of galactic cosmic rays that are observed inside the heliosphere result from the interaction of the spectra present in the local interstellar medium with the structured but turbulent magnetic field carried by the solar wind. Observational tests of solar modulation theory depend on comparisons between spectra inside and outside the heliosphere. Our knowledge of the local interstellar spectra are indirect, using extrapolations of interplanetary spectra measured at high energies where solar modulation effects are minimal and modeling of the physical processes that occur during particle acceleration and transport in the interstellar medium. The resulting estimates of the interstellar spectra can also be checked against observations of the effects that cosmic rays have on the chemistry of the interstellar medium and on the production of the diffuse galactic gamma-ray background. I review the present understanding of the local galactic cosmic-ray spectra, emphasizing the constraints set by observations and the uncertainties that remain. 相似文献
2.
Stone E.C. Cohen C.M.S. Cook W.R. Cummings A.C. Gauld B. Kecman B. Leske R.A. Mewaldt R.A. Thayer M.R. Dougherty B.L. Grumm R.L. Milliken B.D. Radocinski R.G. Wiedenbeck M.E. Christian E.R. Shuman S. von Rosenvinge T.T. 《Space Science Reviews》1998,86(1-4):357-408
The Solar Isotope Spectrometer (SIS), one of nine instruments on the Advanced Composition Explorer (ACE), is designed to provide
high- resolution measurements of the isotopic composition of energetic nuclei from He to Zn (Z=2 to 30) over the energy range
from ∼10 to ∼100 MeV nucl−1. During large solar events SIS will measure the isotopic abundances of solar energetic particles
to determine directly the composition of the solar corona and to study particle acceleration processes. During solar quiet
times SIS will measure the isotopes of low-energy cosmic rays from the Galaxy and isotopes of the anomalous cosmic-ray component,
which originates in the nearby interstellar medium. SIS has two telescopes composed of silicon solid-state detectors that
provide measurements of the nuclear charge, mass, and kinetic energy of incident nuclei. Within each telescope, particle trajectories
are measured with a pair of two-dimensional silicon-strip detectors instrumented with custom, very large-scale integrated
(VLSI) electronics to provide both position and energy-loss measurements. SIS was especially designed to achieve excellent
mass resolution under the extreme, high flux conditions encountered in large solar particle events. It provides a geometry
factor of ∼40 cm2 sr, significantly greater than earlier solar particle isotope spectrometers. A microprocessor controls the
instrument operation, sorts events into prioritized buffers on the basis of their charge, range, angle of incidence, and quality
of trajectory determination, and formats data for readout by the spacecraft. This paper describes the design and operation
of SIS and the scientific objectives that the instrument will address.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
3.
D. J. McComas E. R. Christian N. A. Schwadron N. Fox J. Westlake F. Allegrini D. N. Baker D. Biesecker M. Bzowski G. Clark C. M. S. Cohen I. Cohen M. A. Dayeh R. Decker G. A. de Nolfo M. I. Desai R. W. Ebert H. A. Elliott H. Fahr P. C. Frisch H. O. Funsten S. A. Fuselier A. Galli A. B. Galvin J. Giacalone M. Gkioulidou F. Guo M. Horanyi P. Isenberg P. Janzen L. M. Kistler K. Korreck M. A. Kubiak H. Kucharek B. A. Larsen R. A. Leske N. Lugaz J. Luhmann W. Matthaeus D. Mitchell E. Moebius K. Ogasawara D. B. Reisenfeld J. D. Richardson C. T. Russell J. M. Sokół H. E. Spence R. Skoug Z. Sternovsky P. Swaczyna J. R. Szalay M. Tokumaru M. E. Wiedenbeck P. Wurz G. P. Zank E. J. Zirnstein 《Space Science Reviews》2018,214(8):116
The Interstellar Mapping and Acceleration Probe (IMAP) is a revolutionary mission that simultaneously investigates two of the most important overarching issues in Heliophysics today: the acceleration of energetic particles and interaction of the solar wind with the local interstellar medium. While seemingly disparate, these are intimately coupled because particles accelerated in the inner heliosphere play critical roles in the outer heliospheric interaction. Selected by NASA in 2018, IMAP is planned to launch in 2024. The IMAP spacecraft is a simple sun-pointed spinner in orbit about the Sun-Earth L1 point. IMAP’s ten instruments provide a complete and synergistic set of observations to simultaneously dissect the particle injection and acceleration processes at 1 AU while remotely probing the global heliospheric interaction and its response to particle populations generated by these processes. In situ at 1 AU, IMAP provides detailed observations of solar wind electrons and ions; suprathermal, pickup, and energetic ions; and the interplanetary magnetic field. For the outer heliosphere interaction, IMAP provides advanced global observations of the remote plasma and energetic ions over a broad energy range via energetic neutral atom imaging, and precise observations of interstellar neutral atoms penetrating the heliosphere. Complementary observations of interstellar dust and the ultraviolet glow of interstellar neutrals further deepen the physical understanding from IMAP. IMAP also continuously broadcasts vital real-time space weather observations. Finally, IMAP engages the broader Heliophysics community through a variety of innovative opportunities. This paper summarizes the IMAP mission at the start of Phase A development. 相似文献
4.
R. A. Leske R. A. Mewaldt C. M. S. Cohen A. C. Cummings E. C. Stone M. E. Wiedenbeck T. T. von Rosenvinge 《Space Science Reviews》2007,130(1-4):195-205
Solar energetic particles (SEPs) provide a sample of the Sun from which solar composition may be determined. Using high-resolution
measurements from the Solar Isotope Spectrometer (SIS) onboard NASA’s Advanced Composition Explorer (ACE) spacecraft, we have
studied the isotopic composition of SEPs at energies ≥20 MeV/nucleon in large SEP events. We present SEP isotope measurements
of C, O, Ne, Mg, Si, S, Ar, Ca, Fe, and Ni made in 49 large events from late 1997 to the present. The isotopic composition
is highly variable from one SEP event to another due to variations in seed particle composition or due to mass fractionation
that occurs during the acceleration and/or transport of these particles. We show that various isotopic and elemental enhancements
are correlated with each other, discuss the empirical corrections used to account for the compositional variability, and obtain
estimated solar isotopic abundances. We compare the solar values and their uncertainties inferred from SEPs with solar wind
and other solar system abundances and find generally good agreement. 相似文献
5.
THE CLUSTER ION SPECTROMETRY (CIS) EXPERIMENT 总被引:5,自引:0,他引:5
H. RÈME J. M. Bosqued J. A. Sauvaud A. Cros J. Dandouras C. Aoustin J. Bouyssou Th. Camus J. Cuvilo C. Martz J. L. MÉDALE H. Perrier D. Romefort J. Rouzaud C. D'Uston E. MÖBIUS K. Crocker M. Granoff L. M. Kistler M. Popecki D. Hovestadt B. Klecker G. Paschmann M. Scholer C. W. Carlson D. W. Curtis R. P. Lin J. P. Mcfadden V. Formisano E. Amata M. B. Bavassano-CATTANEO P. Baldetti G. Belluci R. Bruno G. Chionchio A. Di Lellis E. G. Shelley A. G. Ghielmetti W. Lennartsson A. Korth H. Rosenbauer R. Lundin S. Olsen G. K. Parks M. Mccarthy H. Balsiger 《Space Science Reviews》1997,79(1-2):303-350
The Cluster Ion Spectrometry (CIS) experiment is a comprehensive ionic plasma spectrometry package on-board the four Cluster spacecraft capable of obtaining full three-dimensional ion distributions with good time resolution (one spacecraft spin) with mass per charge composition determination. The requirements to cover the scientific objectives cannot be met with a single instrument. The CIS package therefore consists of two different instruments, a Hot Ion Analyser (HIA) and a time-of-flight ion COmposition and DIstribution Function analyser (CODIF), plus a sophisticated dual-processor-based instrument-control and Data-Processing System (DPS), which permits extensive on-board data-processing. Both analysers use symmetric optics resulting in continuous, uniform, and well-characterised phase space coverage. CODIF measures the distributions of the major ions (H+, He+, He++, and O+) with energies from ~0 to 40 keV/e with medium (22.5°) angular resolution and two different sensitivities. HIA does not offer mass resolution but, also having two different sensitivities, increases the dynamic range, and has an angular resolution capability (5.6° × 5.6°) adequate for ion-beam and solar-wind measurements. 相似文献
6.
W. R. Binns M. E. Wiedenbeck M. Arnould A. C. Cummings G. A. de Nolfo S. Goriely M. H. Israel R. A. Leske R. A. Mewaldt G. Meynet L. M. Scott E. C. Stone T. T. von Rosenvinge 《Space Science Reviews》2007,130(1-4):439-449
We have measured the isotopic abundances of neon and a number of other species in the galactic cosmic rays (GCRs) using the
Cosmic Ray Isotope Spectrometer (CRIS) aboard the ACE spacecraft. Our data are compared to recent results from two-component
(Wolf–Rayet material plus solar-like mixtures) Wolf–Rayet (WR) models. The three largest deviations of galactic cosmic ray
isotope ratios from solar-system ratios predicted by these models, 12C/16O, 22Ne/20Ne, and 58Fe/56Fe, are very close to those observed. All of the isotopic ratios that we have measured are consistent with a GCR source consisting
of ∼20% of WR material mixed with ∼80% material with solar-system composition. Since WR stars are evolutionary products of
OB stars, and most OB stars exist in OB associations that form superbubbles, the good agreement of our data with WR models
suggests that OB associations within superbubbles are the likely source of at least a substantial fraction of GCRs. In previous
work it has been shown that the primary 59Ni (which decays only by electron-capture) in GCRs has decayed, indicating a time interval between nucleosynthesis and acceleration
of >105 y. It has been suggested that in the OB association environment, ejecta from supernovae might be accelerated by the high
velocity WR winds on a time scale that is short compared to the half-life of 59Ni. Thus the 59Ni might not have time to decay and this would cast doubt upon the OB association origin of cosmic rays. In this paper we
suggest a scenario that should allow much of the 59Ni to decay in the OB association environment and conclude that the hypothesis of the OB association origin of cosmic rays
appears to be viable. 相似文献
7.
C. M. S. Cohen R. A. Mewaldt R. A. Leske A. C. Cummings E. C. Stone M. E. Wiedenbeck T. T. von Rosenvinge G. M. Mason 《Space Science Reviews》2007,130(1-4):183-194
Solar abundances can be derived from the composition of the solar wind and solar energetic particles (SEPs) as well as obtained
through spectroscopic means. Past comparisons have suggested that all three samples agree well, when rigidity-related fractionation
effects on the SEPs were accounted for. It has been known that such effects vary from one event to the next and should be
addressed on an event-by-event basis. This paper examines event variability more closely, particularly in terms of energy-dependent
SEP abundances. This is now possible using detailed SEP measurements spanning several decades in energy from the Ultra Low
Energy Isotope Spectrometer (ULEIS) and the Solar Isotope Spectrometer (SIS) on the ACE spacecraft. We present examples of
the variability of the elemental composition with energy and suggest they can be understood in terms of diffusion from the
acceleration region near the interplanetary shock. By means of a spectral scaling procedure, we obtain energy-independent
abundance ratios for 14 large SEP events and compare them to reported solar wind and coronal abundances as well as to previous
surveys of SEP events. 相似文献
8.
R. A. Mewaldt C. M. S. Cohen G. M. Mason A. C. Cummings M. I. Desai R. A. Leske J. Raines E. C. Stone M. E. Wiedenbeck T. T. von Rosenvinge T. H. Zurbuchen 《Space Science Reviews》2007,130(1-4):207-219
Although the average composition of solar energetic particles (SEPs) and the bulk solar wind are similar in a number of ways,
there are key differences which imply that solar wind is not the principal seed population for SEPs accelerated by coronal
mass ejection (CME) driven shocks. This paper reviews these composition differences and considers the composition of other
possible seed populations, including coronal material, impulsive flare material, and interplanetary CME material. 相似文献
9.
C.M.S. Cohen R.A. Mewaldt A.C. Cummings R.A. Leske E.C. Stone T.T. von Rosenvinge M.E. Wiedenbeck 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2003,32(12):2649-2654
Using data from the Solar Isotope Spectrometer on the Advanced Composition Explorer obtained during 36large solar energetic particle events (SEPs) that occurred during 1997–2002 we have examined the spectral characteristics of oxygen and iron. Based on the shape of the oxygen spectrum during the decay phase following the peak in particle intensity, each SEP event was categorized as either exponential (7 events) or power law (29 events). We find that the exponential events were typically the larger events (in terms of peak oxygen intensity) and had Fe/0 ratios that strongly decreased with increasing energy.Event-averaged Fe/0 ratios (integrated over 12 to 60 MeV/nucleon) were at or below coronal abundances for nearly all these events, while the ratios obtained in the power law events were typically enhanced over coronal values. The majority of the power law events had the same spectral index for both 0 and Fe resulting in an Fe/0 ratio independent of energy. However 6 of the 29 power law events had Fe/0 ratios that increased with increasing energy due to an Fe spectral index less negative than that of 0. We consider simple diffusion theory in an effort to understand the nature of these events and obtain preliminary but promising results. 相似文献
10.
R. A. Mewaldt C. M. S. Cohen W. R. Cook A. C. Cummings A. J. Davis S. Geier B. Kecman J. Klemic A. W. Labrador R. A. Leske H. Miyasaka V. Nguyen R. C. Ogliore E. C. Stone R. G. Radocinski M. E. Wiedenbeck J. Hawk S. Shuman T. T. von Rosenvinge K. Wortman 《Space Science Reviews》2008,136(1-4):285-362
The Low-Energy Telescope (LET) is one of four sensors that make up the Solar Energetic Particle (SEP) instrument of the IMPACT investigation for NASA’s STEREO mission. The LET is designed to measure the elemental composition, energy spectra, angular distributions, and arrival times of H to Ni ions over the energy range from ~3 to ~30 MeV/nucleon. It will also identify the rare isotope 3He and trans-iron nuclei with 30≤Z≤83. The SEP measurements from the two STEREO spacecraft will be combined with data from ACE and other 1-AU spacecraft to provide multipoint investigations of the energetic particles that result from interplanetary shocks driven by coronal mass ejections (CMEs) and from solar flare events. The multipoint in situ observations of SEPs and solar-wind plasma will complement STEREO images of CMEs in order to investigate their role in space weather. Each LET instrument includes a sensor system made up of an array of 14 solid-state detectors composed of 54 segments that are individually analyzed by custom Pulse Height Analysis System Integrated Circuits (PHASICs). The signals from four PHASIC chips in each LET are used by a Minimal Instruction Set Computer (MISC) to provide onboard particle identification of a dozen species in ~12 energy intervals at event rates of ~1,000 events/sec. An additional control unit, called SEP Central, gathers data from the four SEP sensors, controls the SEP bias supply, and manages the interfaces to the sensors and the SEP interface to the Instrument Data Processing Unit (IDPU). This article outlines the scientific objectives that LET will address, describes the design and operation of LET and the SEP Central electronics, and discusses the data products that will result. 相似文献