Importance of Pickup Ions & Suprathermal Ions in the Inner Heliosphere Eberhard Möbius Space Science Center and Department of Physics, UNH E. Möbius, UNH SSC SPP+ Meeting, Smithsonian, Washington, DC 9/14/16

Pickup Ions - Critical Link in Coupled Plasma Systems Schwadron & Gloeckler 2007 9/14/16 E. Möbius, UNH SSC SPP+ Meeting, Smithsonian, Washington, DC

E. Möbius, UNH SSC SPP+ Meeting, Smithsonian, Washington, DC Summary & Synergies Inner Source Pickup Ions and thus Dust are dynamically important for the SW inside 60 RS PUI Pressure > Thermal & Magnetic Pressure SPP+, Solar Orbiter w. STEREO PUI Transport shifts Focusing Cone vs. Interstellar Flow Direction, Dependence on r Solar 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+!) 9/14/16 E. Möbius, UNH SSC SPP+ Meeting, Smithsonian, Washington, DC

E. Möbius, UNH SSC SPP+ Meeting, Smithsonian, Washington, DC 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-5 Spectra vary v-g: g -5 - -9 with SW conditions SW Compressions form PUI Tails g with ∆u/∆f  Expect distinct variations with r CIRs & CMEs Solar Orbiter, SPP+ w. STEREO, ACE Needed  High collection power & cadence to resolve variations 9/14/16 E. Möbius, UNH SSC SPP+ Meeting, Smithsonian, Washington, DC

Influence on Bulk Solar Wind: Dust & Inner Source Pickup Ions 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? r PUIs map r into v/Vsw v/Vsw Schwadron et al. 2000 9/14/16 E. Möbius, UNH SSC SPP+ Meeting, Smithsonian, Washington, DC

Influence on Bulk Solar Wind: Dust & Inner Source Pickup Ions 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 r PUIs map r into v/Vsw v/Vsw Schwadron et al. 2000 9/14/16 E. Möbius, UNH SSC SPP+ Meeting, Smithsonian, Washington, DC

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 9/14/16 E. Möbius, UNH SSC SPP+ Meeting, Smithsonian, Washington, DC

Interstellar Pickup Ions Close 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 9/14/16 E. Möbius, UNH SSC SPP+ Meeting, Smithsonian, Washington, DC

Interstellar Focusing Cone Close to the Sun Gershman et al. 2013 MESSENGER FIPS ACE SWICS 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? 9/14/16 E. Möbius, UNH SSC SPP+ Meeting, Smithsonian, Washington, DC

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 Orbiter 0.28 AU: Vr = 85 km/s (Vr/Vsw ≈ 11 – 30%) At SPP+ Perihelion 10 RS: Vr ≈ 190 km/s  substantial if observed Wouldn’t it be nice? Observations spread in l & r Solar Orbiter, STEREO +Dedicated PUI Obs 9/14/16 E. Möbius, UNH SSC SPP+ Meeting, Smithsonian, Washington, DC

Modeling of the PUI Cone Relative to Neutral Gas Cone Modeling of PUIs from Interstellar He Cone with EPREM highlights PUI transport effects PUI Cone shifted vs. Neutral Gas cone ISN Flow Quinn et al. 2016 9/14/16 E. Möbius, UNH SSC SPP+ Meeting, Smithsonian, Washington, DC

Modeling of the PUI Cone Relative 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 9/14/16 E. Möbius, UNH SSC SPP+ Meeting, Smithsonian, Washington, DC

Modeling of the PUI Cone Relative 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 Transport of the PUI Cone Observation together with Solar Orbiter, STEREO Quinn et al. 2016 9/14/16 E. Möbius, UNH SSC SPP+ Meeting, Smithsonian, Washington, DC

Acceleration of Pickup Ions in 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. 9/14/16 E. Möbius, UNH SSC SPP+ Meeting, Smithsonian, Washington, DC

Acceleration of Pickup Ions in 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 Tail varies with Compression ∆U/∆f Chen et al. 2015 9/14/16 E. Möbius, UNH SSC SPP+ Meeting, Smithsonian, Washington, DC

He+/He2+ Ratio Dependence on Radial Distance from CIR Along B R [AU] 9/14/16 E. Möbius, UNH SSC SPP+ Meeting, Smithsonian, Washington, DC

E. Möbius, UNH SSC SPP+ Meeting, Smithsonian, Washington, DC Charge States in CIRs He+ ≈ 25% at 1 AU but Majority at 4.5 AU Heavy Ions Consistent with Fast Solar Wind Charge States C and Mg Upper Limit of Singly Charged Ions Ne 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 STEREO Composition variation with r on SPP+ and Orbiter? 9/14/16 E. Möbius, UNH SSC SPP+ Meeting, Smithsonian, Washington, DC

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 9/14/16 E. Möbius, UNH SSC SPP+ Meeting, Smithsonian, Washington, DC

E. Möbius, UNH SSC SPP+ Meeting, Smithsonian, Washington, DC Variable Tail Indices Popecki et al. 2013 STEREO Observations of He+ Tails show Average Index of -4.9 – 6.0 Steeper Indices of up to -9.0 in slow SW Variations pre- and post-shocks 9/14/16 E. Möbius, UNH SSC SPP+ Meeting, Smithsonian, Washington, DC

A Potential Constant Source for 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 9/14/16 E. Möbius, UNH SSC SPP+ Meeting, Smithsonian, Washington, DC

Tail Formation as a Function Distance from the Sun EPREM Modeling for SW Compressions performed at various Solar Distance Quinn et al. 2016, in prep. 1 AU 9/14/16 E. Möbius, UNH SSC SPP+ Meeting, Smithsonian, Washington, DC

Tail Formation as a Function Distance from the Sun EPREM Modeling for SW Compressions performed at various Solar Distance Tails weaker at 0.65 AU Quinn et al. 2016, in prep. 0.65 AU 9/14/16 E. Möbius, UNH SSC SPP+ Meeting, Smithsonian, Washington, DC

Tail Formation as a Function Distance from the Sun EPREM Modeling for SW Compressions performed at 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! Quinn et al. 2016, in prep. 0.28 AU Model CME Evolution Next  Different: Shocks strong at Sun 9/14/16 E. Möbius, UNH SSC SPP+ Meeting, Smithsonian, Washington, DC

E. Möbius, UNH SSC SPP+ Meeting, Smithsonian, Washington, DC Summary & Synergies Inner Source Pickup Ions and thus Dust are dynamically important for the SW inside 60 RS PUI Pressure > Thermal & Magnetic Pressure SPP+, Solar Orbiter w. STEREO PUI Transport shifts Focusing Cone vs. Interstellar Flow Direction, Dependence on r Solar 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+!) 9/14/16 E. Möbius, UNH SSC SPP+ Meeting, Smithsonian, Washington, DC

E. Möbius, UNH SSC SPP+ Meeting, Smithsonian, Washington, DC 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-5 Spectra vary v-g: g -5 - -9 with SW conditions SW Compressions form PUI Tails g with ∆u/∆f  Expect distinct variations with r CIRs & CMEs Solar Orbiter, SPP+ w. STEREO, ACE Needed  High collection power & cadence to resolve variations 9/14/16 E. Möbius, UNH SSC SPP+ Meeting, Smithsonian, Washington, DC

E. Möbius, UNH SSC SPP+ Meeting, Smithsonian, Washington, DC Questions? 9/14/16 E. Möbius, UNH SSC SPP+ Meeting, Smithsonian, Washington, DC