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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.; Milliken, B.; Radocinski, R. G.; Wiedenbeck, M. E.; Christian, E. R.; Shuman, S.; Rosenvinge, T. T. von

doi:10.1023/a:1005027929871

Cited by 161 publications

(65 citation statements)

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“…Since CIRs accelerate particles to modest energies, the bulk of the data reported here were obtained with the Ultra Low Energy Isotope Spectrometer (ULEIS; Mason et al 1998) supplemented above $5 MeV nucleon À1 by observations from the Solar Isotope Spectrometer (SIS; Stone et al 1998b). These instruments achieve a combination of high sensitivity and mass resolution that allows determination of composition and energy spectra to a much higher level of precision than prior studies.…”

Section: Instrumentationmentioning

confidence: 99%

Abundances and Energy Spectra of Corotating Interaction Region Heavy Ions Observed during Solar Cycle 23

Mason

Leske

Desai

et al. 2008

ApJ

103

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Using instruments on the ACE spacecraft, we surveyed the heavy-ion spectra and composition over the range HeFe for 41 corotating interaction regions (CIRs) during 1998-2007. Below $1 MeV nucleon À1 the spectra are power laws in kinetic energy nucleon À1 with an average spectral index of 2:51 AE 0:10, rolling over above $1 MeV nucleon À1 to power-law spectra with an average index of 4:47 AE 0:17. The spectral shapes for different species are similar, leading to relative abundances that are constant over our energy range, even though the intensities cover up to 8 orders of magnitude. Relative to oxygen, the measured abundances at 385 keV nucleon À1 for 4 He, C, N, Ne, Mg, Si, S, Ca, and Fe are 273 AE 72, 0:760 AE 0:023, 0:143 AE 0:005, 0:206 AE 0:009, 0:148 AE 0:006, 0:095 AE 0:005, 0:028 AE 0:002, 0:007 AE 0:001, and 0:088 AE 0:007, respectively. Except for an overabundance of 4 He and Ne, the abundances are quite close to that of the fast solar wind. We have found 3 He/ 4 He ratios to be enhanced over solar wind values in $40% of the CIRs. The Fe/O ratio in individual CIRs is observed to vary over a factor of $10 and is strongly correlated with the solar wind Fe/O ratio measured 2-4 days preceding each CIR. Taken together with previous studies showing the presence of pickup He + in CIRs, the observational data provide evidence that CIR energetic particles are accelerated out of a suprathermal ion pool that includes heated solar wind ions, pickup ions, and remnant suprathermals from impulsive solar energetic particle events.

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Section: Instrumentationmentioning

confidence: 99%

Abundances and Energy Spectra of Corotating Interaction Region Heavy Ions Observed during Solar Cycle 23

Mason

Leske

Desai

et al. 2008

ApJ

103

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“…The SIS instrument consists of a pair of silicon solid-state detector telescopes and uses the dE/dx versus residual energy technique to measure the nuclear charge, Z, mass, M, and total kinetic energy, E, of energetic particles which stop in the device [17]. The ACR species of interest here are measured in energy intervals which range from 6.6-83.3 MeV/nucleon for N to 7.8-101.8 MeV/nucleon for Ne.…”

Section: Elemental Spectramentioning

confidence: 99%

“…The Solar Isotope Spectrometer (SIS) on the Advanced Composition Explorer (ACE) is able to significantly improve upon existing ACR isotope measurements [15,16], owing to its large collecting power and good mass resolution [17]. Since the launch of ACE in August of 1997 under solar minimum conditions, solar modulation of ACRs and GCRs has increased as solar maximum approaches.…”

Section: Introductionmentioning

confidence: 99%

Anomalous cosmic ray composition from ACE

Leske¹

2000

AIP Conference Proceedings

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Abstract. 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, 0, and Ne are studied with SIS. Intensity enhancements are found in low energy 18 O and 22 Ne, 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.

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“…The SIS instrument uses the d /d versus residual energy technique in a pair of silicon solid-state detector telescopes to obtain the nuclear charge, , mass, , and total kinetic energy, , for particles with energies of 10 to 100 MeV/nucleon [8]. For this study, we examined all SEP events with high-energy heavy ion fluxes large enough to yield statistically meaningful isotope abundances for at least a few isotope ratios.…”

Section: Observations and Analysismentioning

confidence: 99%

The Coronal Isotopic Composition as Determined Using Solar Energetic Particles

Leske¹,

Mewaldt²,

Cohen³

et al. 2003

AIP Conference Proceedings

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Abstract. Solar energetic particles (SEPs), like the solar wind, provide a direct sample of the Sun. Although SEP abundances show a variable amount of mass fractionation, it is possible to develop methods of correcting for it in order to deduce the composition of the corona. Using high-resolution measurements from the Solar Isotope Spectrometer on the Advanced Composition Explorer, we have studied the isotopic composition of 10 abundant elements from C to Ni in 32 large SEP events from late 1997 to the end of 2001 at energies 15 MeV/nucleon. We show that various isotopic and elemental enhancements are correlated with each other, discuss the first order corrections used to account for the variability, and obtain estimated coronal abundances. We compare the coronal values and their uncertainties inferred from SEPs with those that are available from solar wind and meteoritic measurements and find generally good agreement. We include C and Ni isotopic abundances, for which no solar wind measurements have yet been reported.

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Cited by 161 publications

References 0 publications

Abundances and Energy Spectra of Corotating Interaction Region Heavy Ions Observed during Solar Cycle 23

Abundances and Energy Spectra of Corotating Interaction Region Heavy Ions Observed during Solar Cycle 23

Anomalous cosmic ray composition from ACE

The Coronal Isotopic Composition as Determined Using Solar Energetic Particles

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