SHINE 2006

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Review of CIR-related Particle Composition,
Charge States, Energy Spectra
Joe Mazur The Aerospace Corporation Glenn
Mason Johns Hopkins/APL Joe Dwyer Florida
Institute of Technology Mihir Desai Southwest
Research Institute
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Processes for 1 AU observations of solar material
After Stone et al., Space Sci Rev., 86, 1, 2000
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5 AU
1 AU
Desai et al., JGR, 104, 6705, 1999
Mason et al., ApJ Letters, 486, L149, 1997
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Stream interface
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Abundances
Mason et al., ApJ Letters, 486, L149, 1997 see
also Richardson et al., JGR 98, 13, 1993
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Ratios vs. solar wind speed
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Abundance summary

• similar to solar system except for factor of 2-3
  enhancement of He and C/O
• increase of He/O, C/O, and Ne/O with solar wind
  speed
• He abundance increases from 1 to 5 AU

Mason von Steiger et al. Space Sci. Rev. 89,
1999 (ISSI CIR Workshop held in 1998)
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Ulysses 4.5 AU
Pick up ion He increases its contribution to
CIRs at greater radial distances Suggested that
other pickup ions (such as inner source) at 1 AU
might account for some puzzling composition
observations
Gloeckler et al., JGR, 99, 17637, 1994.
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Acceleration of suprathermal He in CIRs
enhanced 103 - 104 over solar wind
Chotoo et al., JGR, 105, 23107, 2000.
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Mazur et al. ApJ 566, 2002
Mobius et al. Geophysical Research Letters, 29,
2001
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Averaged CIR charge states 0.5 MeV/n
Species SAMPEX ACE
He 2.000.12 -
C 4.830.27 5.10.3
O 6.120.37 6.10.35
Ne 7.250.25 7.80.5
Fe 13.000.48 10.50.6
Mobius et al. Geophysical Research Letters, 29,
2001
Mazur et al. ApJ 566, 2002
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Möbius et al., AIP Conf. Proc. 598, 201, 2001
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Charge state summary

• More pickup He at 4.5 AU than 1 AI (at 1 AU the
  pickup He is 15 He, while at 4.5 AU it is
  twice as abundant)
• Heavy ions at 1 AU show little evidence of pickup
  species

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Mason et al., ApJ Letters, 486, L149, 1997
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Summary

• Abundances
• Ion composition similar to solar system but with
  some differences
• Still puzzling dependence of some ratios on
  solar wind speed
• Charge states
• Little evidence of Zgt2 pickup ions at 1 AU
• Large abundance of pickup helium at 5 AU
• Energy spectra
• Power law from tens of keV/n to 1 MeV/n
• Steepening above 1 MeV/n
• Spectral forms do not change out to 10s of AU
• The source population is coming from the
  suprathermal region, but that population is not
  just heated solar wind other constituents are
  important
• Most often the 1 AU particles are not accelerated
  at shocks requiring another mechanism (Jokipii et
  al. 2003)
• As we approach solar minimum we have the
  opportunity to revisit some of these observables
  with ACE

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Essential new work needed

• Complete ACE surveys with much larger number of
  species identified
• fully characterize properties of suprathermal /
  pick-up ion distributions
• detailed theoretical models to probe injection
  issues

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C. Chotoo, Ph.D. thesis, U of Maryland 1998
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Energy spectra summary

• power law from tens of keV/n to 1 MeV/n
• steepening above 1 MeV/n
• spectral forms do not change out to 10s of AU

See also Mason von Steiger et al. Space Sci.
Rev. 89, 1999 (ISSI CIR Workshop held in 1998)
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Energy spectra summary

• More pickup He at 4.5 AU than 1 AI (at 1 AU the
  pickup He is 15 He, while at 4.5 AU it is
  twice as abundant)
• Heavy ions at 1 AU show little evidence of pickup
  species

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Möbius et al., AIP Conf. Proc. 598, 201, 2001
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Möbius et al., AIP Conf. Proc. 598, 201, 2001
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Richardson et al., JGR, 98, 13, 1993
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Dwyer et al, in preparation, 2002
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Fisk Lee acceleration model--

• particles in CIRs accelerated by compression at
  forward and reverse shocks at several AU
  propagate in to 1 AU
• adiabatic deceleration in solar wind included
• yields distribution function spectra and
  gradients similar to observations above 100
  keV/n
• injection energy gt 5 keV required, ie from
  postulated suprathermal tail of the solar wind
• composition similar to source material (assumed
  to be solar wind suprathermal tail) -- (note no
  systematic measurements of solar wind comp.
  available at that time)

L. A. Fisk and M. A. Lee, Astrophys. J., 237,
620, 1980
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Suprathermals as a seed population--

• SEP related events
• super events in the inner solar-system (Dröge
  et al. 1992.)
• Peak intensities in August 1972 (Smart et al.
  1990)
• Interplanetary shocks
• Aug 1978 shock (Gosling et al. 1981)
• IP shock survey (Tsurutani Lin 1985)
• Sources?
• long lived remnants of solar flares
• planetary bow shocks
• corotating interaction regions

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Fisk Lee CIR spectral form--
CIR spectral form where v particle speed
r radius of observer rs shock radius ??
shock strength ???diffusion coefficient? V
solar wind speed
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CIR model status 1970s-80s

• Successful
• spectra above 100 keV/n
• composition similar to (unmeasured) solar wind
• origin at several AU, and gradients
• Not successful / unaddressed
• C/O ratio
• spectral forms vs. compression ratios
• intensities

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New CIR energetic particle observations
challenges to standard model--

• Particle spectra continue to rise down to 10
  keV/nucleon at 1 AU
• C/O ratio dependence on solar wind speed
• Mg/O shows no FIP effect
• large abundance of He at 1 and several AU
• 3He abundance enhanced compared to solar wind

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solids, yeast, salt, contains 2 or less of the
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sugar, natural (vegetable and dairy source) and
artificial flavors, butter oil, alpha-tocopherol
(antioxidant), smoke flavor, enzymes, L-cysteine,
TBHQ (to preserve freshness).
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Hilchenbach et al., Trnas. Am.Geophys. U., 78,
F554, 1997
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Interstellar Gas Flow in Inner Solar System
From University of New Hampshire group WWW
page http//www-ssg.sr.unh.edu/tof/Missions/Ace/ac
eset.html
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3He is enriched in CIRs -- about 4 times the
solar wind value compared to 4He
Dwyer et al, in preparation, 2002
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Role of pick up ions --

• consistent with He abundance
• tempting explanation for C/O ratio, but
• no seasonal variation of heavy ion abundances
  detected, but data is sparse
• at 1 AU C is a small fraction of CIR carbon

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CY 1994, ltrgt 2.8AU ltlatitudegt -65 ltvswgt784
km/s
Gloeckler Geiss, Space Sci. Rev, 86, 127, 1998
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SAMPEX geomagnetic latitude cutoffs of (a) 14
CIRs (1992- 95), and (b) all 1998 SEP events
Mazur, Mason Mewaldt, 2002, ApJ, in press
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SAMPEX Calibration of adjusted magnetic
invariant latitude cutoffs for CIRs and SEP
events
Mazur, Mason Mewaldt, 2002, ApJ, in press
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SAMPEX Observed magnetic cutoffs for CIR
events, vs inferred cutoff if ions were singly
ionized. Singly stripped ions must be no more
than a few percent of total.
Mazur, Mason Mewaldt, 2002, ApJ, in press
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CIR abundance details show that bulk solar wind
source does not fit the new observations--

• Source population is coming from suprathermal
  region, but that population is not just heated
  solar wind -- other constituents important
• Do other shock-associated energetic particle
  observations show evidence for suprathermal seed
  ions? YES SEPs, ESPs -- tracer ion is 3He

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3He and 4He time intensity profiles in large
June 4, 1999 solar particle event
Mason et al., Ap.J. Letters, 525, L133, 1999
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Enhanceed abundances of 3He in large SEP events
ACE/SIS 8-13 MeV/n
ACE/ULEIS 0.5-2 MeV/n
Wiedenbeck et al., AIP Conf Proc 528, 107, 2000
Mason et al., Ap.J. Letters, 525, L133, 1999
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Suprathermals show 10-100 times more variation in
intensity than solar wind -- likely critical
issue in energetic particle intensities
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Conclusions 1 AU CIRs

• CIR source is not bulk solar wind, but rather the
  suprathermal region (v/vsw gt 1.5)
• time dependent, multiple ingredients
• solar wind suprathermal tail
• pick up ions (interstellar)
• pick up ions (inner source)
• other remnants (large SEP events, impulsive SEP
  events)
• at lt few hundred keV/n, CIR ions are locally
  accelerated

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• CIRs observed in early 2000 on ACE
• typical appearance
• note change in C/O ratio in CIRs vs. solar events

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Introduction

• Dependence of some abundances on coronal hole
  speed
• No reflection of solar wind abundance changes
  across stream interface - pointing to another
  source (the suprathermals) / Ubiquitous tails
• Little influence of Zgt2 pickup ions at 1 AU
• Most 1 AU events dont have shocks
• complicated time profile that includes local
  acceleration and transport of ions from shocks
  later in the events, as long as a week (Reames)