Element Abundances: A New Diagnostic for the Solar Wind

Laming, J. Martin; Vourlidas, A.; Korendyke, C. M.; Chua, D.; Cranmer, Steven R.; Ko, Yuan‐Kuen; Kuroda, Natsuha; Provornikova, Elena; Raymond, J. C.; Raouafi, N. E.; Strachan, L.; Tun-Beltran, Samuel; Weberg, M. J.; Wood, Brian E.

doi:10.3847/1538-4357/ab23f1

Cited by 80 publications

(110 citation statements)

References 135 publications

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“…It turns out that the region of high Si/S seems confined to closed magnetic loops and active regions which comparisons of SEP abundances with FIP theory (Fig. 2(a); Reames 2018a; Laming et al 2019) have told us to be the origin of SEPs. This helps to confirm the origin of plasma that will become SEPs.…”

Section: Entering the Corona: The Fip Effectmentioning

confidence: 91%

Four Distinct Pathways to the Element Abundances in Solar Energetic Particles

Reames

2020

Space Sci Rev

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Based upon recent evidence from abundance patterns of chemical elements in solar energetic particles (SEPs), and, ironically, the belated inclusion of H and He, we can distinguish four basic SEP populations: (1) SEP1 -pure "impulsive" SEPs are produced by magnetic reconnection in solar jets showing steep power-law enhancements of 1≤ Z ≤ 56 ions versus charge-to-mass ratio A/Q from a ≈3 MK plasma.(2) SEP2ambient ions, mostly protons, plus SEP1 ions reaccelerated by the shock wave driven by the narrow coronal mass ejection (CME) from the same jet. (3) SEP3 -a "gradual" SEP event is produced when a moderately fast, wide CME-driven shock wave barely accelerates ambient protons while preferentially accelerating accumulated remnant SEP1 ions from an active region fed by multiple jets. (4) SEP4 -a gradual SEP event is produced when a very fast, wide CME-driven shock wave is completely dominated by ambient coronal seed population of 0.8 -1.8 MK plasma usually producing a full power law vs. A/Q for 1≤ Z ≤ 56 ions. We begin with element abundances in the photosphere that are fractionated during transport up to the corona based upon their first ionization potential (FIP); this important "FIP effect" for SEPs provides our reference abundances and is different for SEPs from that for the solar wind. We then show evidence for each of the processes of acceleration, reacceleration, and transport that conspire to produce the four abundances patterns we distinguish.

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Section: Entering the Corona: The Fip Effectmentioning

confidence: 91%

Four Distinct Pathways to the Element Abundances in Solar Energetic Particles

Reames

2020

Space Sci Rev

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“…When Bochsler (2007) suggested that the Apollo solar wind foil data on helium and neon, while ambiguous, were consistent with a Coulomb drag model (described in the Discussion), he indirectly acknowledged that sample return was necessary to obtain precision data. Laming et al (2017) presented a quantitative model demonstrating how isotopic and elemental (primarily FIP) fractionation in the SW may be related, driven by magnetohydrodynamic waves whose interactions vary spatially and cause the variations in the SW fractionation and velocity with the solar source region observed by spacecraft (detailed overview in Laming et al 2019). This last solar physics model relies heavily on a baseline SW composition determined from laboratory measurement of SW samples collected and returned to the Earth by the Genesis SW Sample Return mission.…”

Section: Mass Fractionation In the Sw: Previous Work In Solar Physicsmentioning

confidence: 99%

“…() presented a quantitative model demonstrating how isotopic and elemental (primarily FIP) fractionation in the SW may be related, driven by magnetohydrodynamic waves whose interactions vary spatially and cause the variations in the SW fractionation and velocity with the solar source region observed by spacecraft (detailed overview in Laming et al. ). This last solar physics model relies heavily on a baseline SW composition determined from laboratory measurement of SW samples collected and returned to the Earth by the Genesis SW Sample Return mission.…”

Section: Introductionmentioning

confidence: 99%

Magnesium isotopes of the bulk solar wind from Genesis diamond‐like carbon films

Jurewicz

Rieck

Hervig

et al. 2020

Meteorit & Planetary Scien

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NASA's Genesis Mission returned solar wind (SW) to the Earth for analysis to derive the composition of the solar photosphere from solar material. SW analyses control the precision of the derived solar compositions, but their ultimate accuracy is limited by the theoretical or empirical models of fractionation due to SW formation. Mg isotopes are “ground truth” for these models since, except for CAIs, planetary materials have a uniform Mg isotopic composition (within ≤1‰) so any significant isotopic fractionation of SW Mg is primarily that of SW formation and subsequent acceleration through the corona. This study analyzed Mg isotopes in a bulk SW diamond‐like carbon (DLC) film on silicon collector returned by the Genesis Mission. A novel data reduction technique was required to account for variable ion yield and instrumental mass fractionation (IMF) in the DLC. The resulting SW Mg fractionation relative to the DSM‐3 laboratory standard was (−14.4‰, −30.2‰) ± (4.1‰, 5.5‰), where the uncertainty is 2ơ SE of the data combined with a 2.5‰ (total) error in the IMF determination. Two of the SW fractionation models considered generally agreed with our data. Their possible ramifications are discussed for O isotopes based on the CAI nebular composition of McKeegan et al. (2011).

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“…It is not sufficient that the field lines open later to produce the SSW, they must be open when that plasma crosses the chromosphere and enters the corona, since that is when its FIP is, or is not, controlled by resonant Alfvén waves. The difference that we have found between SEPs and the solar wind is as important for understanding the solar wind as for understanding SEPs [13,59,87,88].…”

Section: Comparing Seps With the Solar Windmentioning

confidence: 83%

“…These shocks often form out beyond the orbit of Earth and the accelerated ions show power-law abundance variations in A/Q as they flow inward. CIR measurements [90] provide an additional measurement of the FIP-dependence of the solar wind abundances [59,88] and they are included in Figure 9. [59] with the closed loop model of Laming [87] (Table 3).…”

Section: Comparing Seps With the Solar Windmentioning

confidence: 99%

Element Abundances of Solar Energetic Particles and the Photosphere, the Corona, and the Solar Wind

Reames

2019

Atoms

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From a turbulent history, the study of the abundances of elements in solar energetic particles (SEPs) has grown into an extensive field that probes the solar corona and physical processes of SEP acceleration and transport. Underlying SEPs are the abundances of the solar corona, which differ from photospheric abundances as a function of the first ionization potentials (FIPs) of the elements. The FIP-dependence of SEPs also differs from that of the solar wind; each has a different magnetic environment, where low-FIP ions and high-FIP neutral atoms rise toward the corona. Two major sources generate SEPs: The small "impulsive" SEP events are associated with magnetic reconnection in solar jets that produce 1000-fold enhancements from H to Pb as a function of massto-charge ratio A/Q, and also 1000-fold enhancements in 3 He/ 4 He that are produced by resonant wave-particle interactions. In large "gradual" events, SEPs are accelerated at shock waves that are driven out from the Sun by wide, fast coronal mass ejections (CMEs). A/Q dependence of ion transport allows us to estimate Q and hence the source plasma temperature T. Weaker shock waves favor the reacceleration of suprathermal ions accumulated from earlier impulsive SEP events, along with protons from the ambient plasma. In strong shocks, the ambient plasma dominates. Ions from impulsive sources have T ≈ 3 MK; those from ambient coronal plasma have T = 1 -2 MK. These FIPand A/Q-dependences explore complex new interactions in the corona and in SEP sources.Forbush first observed the effects of SEPs [2], as increases in GeV particles that caused nuclear cascades through the atmosphere to produce what we now call ground-level events (GLEs). These SEPs were visually associated with solar flares and it was commonly assumed that the flares themselves caused SEP events in some way, but there were problems; for example, SEPs that were associated with these flares were eventually found to span more than 180° in solar longitude, which suggests a broad spatial distribution. How could the SEPs from a point-source flare cross magnetic field lines over such a distance? Newkirk and Wenzel [3] proposed the "birdcage" model where SEPs Atoms 2019, 7, 104 2 of 16 could follow coronal magnetic loops that then spread across the Sun like the wires of a birdcage. The birdcage model reigned many years, but Mason, et al. [4] argued that abundances of ions of different rigidity were unaffected by a trip through such a complex magnetic birdcage; they must arise from large-scale shock acceleration. At the same time, Kahler et al. [5] found a 96% correlation between large energetic SEP events and wide, fast coronal mass ejections (CMEs), which had just been discovered several years before. We now know that CMEs drive extensive expanding sun-spanning shock waves, where SEPs are accelerated to produce what we now call "long-duration" or "gradual" SEP events. Considerable controversy arose again with the publication of Gosling's [6] review article entitled "The Solar Flare Myth", which was alleged...

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Element Abundances: A New Diagnostic for the Solar Wind

Cited by 80 publications

References 135 publications

Four Distinct Pathways to the Element Abundances in Solar Energetic Particles

Four Distinct Pathways to the Element Abundances in Solar Energetic Particles

Magnesium isotopes of the bulk solar wind from Genesis diamond‐like carbon films

Element Abundances of Solar Energetic Particles and the Photosphere, the Corona, and the Solar Wind

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