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Importance of Pickup Ions & Suprathermal Ions in the Inner Heliosphere

Importance of Pickup Ions & Suprathermal Ions in the Inner Heliosphere. Eberhard Möbius Space Science Center and Department of Physics, UNH. Pickup Ions - Critical Link in Coupled Plasma Systems. Schwadron & Gloeckler 2007. Summary & Synergies.

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Importance of Pickup Ions & Suprathermal Ions in the Inner Heliosphere

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  1. Importance of Pickup Ions & Suprathermal Ions in the Inner Heliosphere Eberhard MöbiusSpace Science Center and Department of Physics, UNH E. Möbius, UNH SSC SPP+ Meeting, Smithsonian, Washington, DC

  2. Pickup Ions - Critical Link in Coupled Plasma Systems Schwadron & Gloeckler2007 E. Möbius, UNH SSC SPP+ Meeting, Smithsonian, Washington, DC

  3. Summary & Synergies • Inner Source Pickup Ions and thus Dust are dynamically important for the SW inside 60 RSPUI Pressure > Thermal & Magnetic PressureSPP+, Solar Orbiter w. STEREO • PUI Transport shifts Focusing Cone vs. Interstellar Flow Direction, Dependence on rSolar Orbiter, SPP+? w. STEREO + IBEX• Dedicated PUI & Suprathermal Observations• Need combined Nano Dust & Optimized PUI Observation with B-Field at 1 AU (no Dust on SPP+!) E. Möbius, UNH SSC SPP+ Meeting, Smithsonian, Washington, DC

  4. Summary & Synergies • Energ. He+/He2+ prop. r in CIRs, different in CMEs?Solar Orbiter, SPP+ w. STEREO, ACE • Averaged Quiet Time Suprathermal Tails as v-5Spectra vary v-g: g -5 - -9 with SW conditionsSW Compressions form PUI Tails g with ∆u/∆f Expect distinct variations with r CIRs & CMEsSolar Orbiter, SPP+ w. STEREO, ACENeeded High collection power & cadence to resolve variations E. Möbius, UNH SSC SPP+ Meeting, Smithsonian, Washington, DC

  5. Influence on Bulk Solar Wind:Dust & Inner Source Pickup Ions r • Inner Source Pickup Ions generated by Solar Wind – Dust Interaction close to the Sun absorption/reemission,sputtering, or penetration • Total Dust Cross-Section x100 > than observed plenty of nano-dust? PUIs map r into v/Vsw v/Vsw Schwadron et al. 2000 E. Möbius, UNH SSC SPP+ Meeting, Smithsonian, Washington, DC

  6. Influence on Bulk Solar Wind:Dust & Inner Source Pickup Ions r • Inner Source Pickup Ions generated by Solar Wind – Dust Interaction close to the Sun absorption/reemission,sputtering, or penetration • nH+ ≈ 1.2 cm-3 at 60 RS*Vsw2: p ≈ 1.2 10-8 erg/cm-3> pSWTh ≈ 6 10-9 erg/cm-3> pB ≈ 4 10-9 erg/cm-3 PUI/Dust Important PUIs map r into v/Vsw v/Vsw Schwadron et al. 2000 E. Möbius, UNH SSC SPP+ Meeting, Smithsonian, Washington, DC

  7. Studying the Dynamic Interaction of Dust/Pickup Ions & Solar Wind • Dust and its Products (PUIs) important for the Solar Wind Energy Balance close to the Sun- May be greatly amplified by inhomogeneous Dust Distributions •  Combine in-situ SW Observations on SPP+ & Solar Orbiter with- Inner Source PUI Measurements on • Solar Orbiter, STEREO - Inner Source PUIs & Nano Dust Distributions Would be great to observe at 1 AU for synergy E. Möbius, UNH SSC SPP+ Meeting, Smithsonian, Washington, DC

  8. Interstellar Pickup IonsClose to the Sun • Interstellar He substantial inside 1 AU (30% of ISN at 0.3 AU, ≈10% at 0.1 AU at Solar Min, ≈1/3 at Max)Enhanced in Focusing Cone • Allows Study of:- Interstellar Parameters- Pickup Ion Transport (Stable Cone Structure)- Variation of Ionization- Source for Energetic Ions from Möbius et al. 2004 E. Möbius, UNH SSC SPP+ Meeting, Smithsonian, Washington, DC

  9. Interstellar Focusing ConeClose to the Sun Gershman et al. 2013 • Focusing Cone observations with STEREO (Drews et al. 2012), ACE & MESSENGER suggest shift of the Cone location vs. the Interstellar Flow direction (with IBEX & Ulysses) PUI Transport? Variation with r? MESSENGERFIPS ACE SWICS E. Möbius, UNH SSC SPP+ Meeting, Smithsonian, Washington, DC

  10. PUI Cut-Off in the Innermost Heliosphere • Radial Flow Component Vr of Interstellar Gas PUI Cut-Off (~1/√r)  ISN Direction w. IBEX • 1 AU: Vr = 50 km/s (6-20% of Vsw =800-250 km/s) • At Perihelion of Solar Orbiter0.28 AU: Vr = 85 km/s (Vr/Vsw ≈ 11 – 30%) • At SPP+ Perihelion10 RS: Vr ≈ 190 km/s  substantial if observed • Wouldn’t it be nice? Observations spread in l & rSolar Orbiter, STEREO +Dedicated PUI Obs E. Möbius, UNH SSC SPP+ Meeting, Smithsonian, Washington, DC

  11. Modeling of the PUI ConeRelative to Neutral Gas Cone • Modeling of PUIs from Interstellar He Cone with EPREM highlights PUI transport effectsPUI Cone shifted vs. Neutral Gas cone ISN Flow Quinn et al. 2016 E. Möbius, UNH SSC SPP+ Meeting, Smithsonian, Washington, DC

  12. Modeling of the PUI ConeRelative to Neutral Gas Cone • Modeling of PUIs from Interstellar He Cone with EPREM highlights shift of PUI Cone vs. Neutral Gas • Adiabatic Focusing & Diffusion | B prevalent Quinn et al. 2016 E. Möbius, UNH SSC SPP+ Meeting, Smithsonian, Washington, DC

  13. Modeling of the PUI ConeRelative to Neutral Gas Cone • Modeling of PUIs from Interstellar He Cone with EPREM highlights shift of PUI Cone vs. Neutral Gas • Adiabatic Focusing & Diffusion | B prevalent • Distinct radial evolution in Azimuthal Transportof the PUI Cone • Observation together withSolar Orbiter, STEREO Quinn et al. 2016 E. Möbius, UNH SSC SPP+ Meeting, Smithsonian, Washington, DC

  14. Acceleration of Pickup Ionsin Compression Regions • Related EPREM Modeling with SW Compression & Rarefaction Regions shows- Reshaping of PUI Spectra- Formation of Tails in Compressions for Interstellar & Inner Source Quinn et al. 2016, in prep. E. Möbius, UNH SSC SPP+ Meeting, Smithsonian, Washington, DC

  15. Acceleration of Pickup Ionsin Compression Regions • Related EPREM Modeling with SW Compression & Rarefaction Regions shows- Reshaping of PUI Spectra- Formation of Tails in Compressions for Interstellar & Inner Source • Power Law Index of Tailvaries with Compression∆U/∆f Chen et al. 2015 E. Möbius, UNH SSC SPP+ Meeting, Smithsonian, Washington, DC

  16. He+/He2+ Ratio Dependence onRadial Distance from CIR Along B R [AU] E. Möbius, UNH SSC SPP+ Meeting, Smithsonian, Washington, DC

  17. He+ ≈ 25% at 1 AUbut Majority at 4.5 AU • Heavy Ions Consistent with Fast Solar Wind Charge States • C and Mg Upper Limit of Singly Charged IonsNe has Small (4.7%) Contribution of Ne+O+ no Statistically Significant Contribution • He2+ and Most Heavy Ions are Solar Wind • He+ and Ne+ from ISM Pickup Ions (≈100x increased acceleration efficiency over solar wind) • No Noticeable Inner Source Contribution  Need Larger Collection Power and r Dependence & Solar Orbiter together with STEREOComposition variation with r on SPP+ and Orbiter? Charge States in CIRs E. Möbius, UNH SSC SPP+ Meeting, Smithsonian, Washington, DC

  18. Suprathermal Tails & Seed Particles for Acceleration • Quiet Time Averaged Tails observed with v-5 and exponential fall-off • PUIs & Remnant Impulsive SEPs preferentially accelerated • Do we have a “Reservoir”? Are there variations? Any almost constant source How do Tails vary with r Fisk & Gloeckler 2008 E. Möbius, UNH SSC SPP+ Meeting, Smithsonian, Washington, DC

  19. Variable Tail Indices • STEREO Observations of He+ Tails showAverage Index of -4.9 – 6.0 Steeper Indices of up to -9.0 in slow SWVariations pre- and post-shocks Popecki et al. 2013 E. Möbius, UNH SSC SPP+ Meeting, Smithsonian, Washington, DC

  20. A Potential Constant Sourcefor Suprathermal Tails • Schwadron & McComas(2010) proposed ENAs as another source for PUIs • Modeling suggests that the ISN is much stronger, but ENAs could contribute to tails ≈v-9 • ENA Tails ≈ v-9 super quiet time?? Dominantly H+ Bochsler & Möbius 2010 E. Möbius, UNH SSC SPP+ Meeting, Smithsonian, Washington, DC

  21. Tail Formation as a Function Distance from the Sun Quinn et al. 2016, in prep. • EPREM Modeling for SW Compressions performedat various Solar Distance 1 AU E. Möbius, UNH SSC SPP+ Meeting, Smithsonian, Washington, DC

  22. Tail Formation as a Function Distance from the Sun Quinn et al. 2016, in prep. • EPREM Modeling for SW Compressions performedat various Solar Distance • Tails weaker at 0.65 AU 0.65 AU E. Möbius, UNH SSC SPP+ Meeting, Smithsonian, Washington, DC

  23. Tail Formation as a Function Distance from the Sun Quinn et al. 2016, in prep. • EPREM Modeling for SW Compressions performedat various Solar Distance • Tails weaker at 0.65 AU • Tails form with increasing Compression • At 0.28 AU (Solar Orbiter Perihelion) Tails are gone • CME Compressions & Shocks stronger here! 0.28 AU Model CME Evolution Next Different: Shocks strong at Sun E. Möbius, UNH SSC SPP+ Meeting, Smithsonian, Washington, DC

  24. Summary & Synergies • Inner Source Pickup Ions and thus Dust are dynamically important for the SW inside 60 RSPUI Pressure > Thermal & Magnetic PressureSPP+, Solar Orbiter w. STEREO • PUI Transport shifts Focusing Cone vs. Interstellar Flow Direction, Dependence on rSolar Orbiter, SPP+? w. STEREO• Dedicated PUI & Suprathermal Observations• Need combined Nano Dust & Optimized PUI Observation with B-Field at 1 AU (no Dust on SPP+!) E. Möbius, UNH SSC SPP+ Meeting, Smithsonian, Washington, DC

  25. Summary & Synergies • Energ. He+/He2+ prop. r in CIRs, different in CMEs?Solar Orbiter, SPP+ w. STEREO, ACE • Averaged Quiet Time Suprathermal Tails as v-5Spectra vary v-g: g -5 - -9 with SW conditionsSW Compressions form PUI Tails g with ∆u/∆f Expect distinct variations with r CIRs & CMEsSolar Orbiter, SPP+ w. STEREO, ACENeeded High collection power & cadence to resolve variations E. Möbius, UNH SSC SPP+ Meeting, Smithsonian, Washington, DC

  26. Questions? E. Möbius, UNH SSC SPP+ Meeting, Smithsonian, Washington, DC

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