Thanks to: Margaret Kivelson David Brain Steve Bartlett

1. From Core to Solar Wind Studying the Space Environment of Planets Thanks to: Margaret Kivelson David Brain Steve Bartlett Fran Bagenal University of Colorado

2. The Space Environment of Planets Ganymede, Mercury - what a magnetic field says about a core - magnetosphere within a magnetosphereMars - surface magnetization - atmospheric lossEuropa, Callisto - radiation of surfaces - induction in conducting shell -> waterIo - volcanism, patchy atmosphere - auroraComets + Pluto

3. 1 2 and 1 2 Planetary Dynamos Volume of electrically conducting fluid ... which is convecting ... and rotating All planetary objects probably have enough rotation - the presence (or not) of a global magnetic field tells us about

4. Scales Earth Magnetospheres of the Giant Planets • LARGE • Rotating with planet • Jupiter + Saturn: • dipole with small tilt • dynamo in metallic hydrogen • Uranus + Neptune: • multipole, large tilt • dynamo in water/ammonia/methane layer

5. Mercury & Ganymede Mercury - Magnetic field detected by Mariner 10 in 1974 Ganymede - Magnetic field detected by Galileo in 1996 Solar Wind Bsurface ~ 1/100 Earth Diameter of Earth

6. Mercury & Ganymede What drives convection in these small bodies? “The test of a good theorist is the ability to explain any outcome, even when the data are wrong” - David Stevenson Liquid Fe + S Core MESSENGER 201? JIMO ? Iron Core -Liquid? Liquid Iron Core

7. Ganymede: A Magnetosphere within a Magnetosphere Torrence Johnson

8. Open-closed boundary Ganymede’s mini-magnetosphere controls the motion of energetic charged particles Ambient magnetic field Closed Ganymede magnetic field lines Galileo Magnetic field coupling Ganymede to Jupiter Kivelson et al. 1996

9. HST observations of oxygen emissions - McGrath Energetic Particles Trailing Side = Upstream North Polar Cap Leading Side = Downstream South Polar Cap Khurana & Pappalardo Aurora on Ganymede

10. Mars Global SurveyorMagnetometer - PI: M. Acuna

11. No core dynamo today Magnetization of surface rocks

13. Magnetization only of old, cratered terrain -> Dynamo ceased ~3.5 billion years ago

14. Ionosphere

15. Atmospheric Loss Processes Neutral Bulk removal “stripping” Ion Ion pickup Photochemical loss Sputtering

16. Crustal magnetic sources affect these processes: shielding atmosphere from SW field topology open field lines

17. MGS Measurements - Implications for Mars’ Atmosphere • Ancient dynamo • -> early protection for atmosphere • Strong crustal magnetization • -> affect atmospheric loss after dynamo turn-off

18. Solar Wind Interaction Boundary Pressure Balance: obstacle to the solar wind PSolar Wind = P (magnetic)crust + P (thermal)ionosphere David Brain

19. Mars’Interaction Boundary Response to the Solar Wind

20. Field Topology Solar wind and magnetic field impinging on Mars’ complex magnetic field Close-up of strong anomaly region David Brain

21. Changing Topology of Mars’ Magnetic Field

22. Over a Strong Magnetic Region

23. Mars Aeronomy Mission • Upper atmosphere • Ionosphere • Magnetic Field • Pick-Up Ions • Solar Wind

24. Galileo Mission

25. The Galilean Satellites

27. Title The Magnetosphere of JupiterNew Perspectives from Galileo and Cassini Io Europa Ganymede Callisto Fran Bagenal University of Colorado Think of a moon embedded in a plasma which overtakes the moon in the direction of its orbital motion.

28. Europa & Callisto Radiolysis - • Bombardment of surface ices and mineralsby energetic particles from the magnetosphere • changes chemistry • alters grain size • embedded heavy ions • sputtering “Because of the magnetosphere, the Galilean satellites have all lost the equivalent of a Titan (or Earth) atmosphere over the past billion years” - Bob Johnson THEN - the atmosphere is ionized & stripped away by the magnetosphere Galileo Near InfraRed Mapping Spectrometer image of Europa showing distribution of hydrated sulfur compounds

29. Induced Currents -> Oceans • A moon sees a changing magnetic field as Jupiter’s tilted magnetosphere rotates • Electrical currents induced in a electrically conducting layer produce a magnetic perturbation - observed by Galileo • Observed magnetic field perturbations imply water layers in Callisto and Europa, possibly Ganymede • Depth and thickness of water layer not uniquely determined Life!

30. Io 300 km Amirani

31. Pilan Plume Io’s Volcanoes& Geysers Prometheus Pilan 5 months apart Pele Infrared glow

32. Io at night - Galileo visible image Glowing Lava Plume Gas & Dust + Aurora

33. After Spencer & Schneider 1996

34. Plasma collides with atmosphere on the flanks

35. Io-plasma interaction: HST data vs model Jupiter Flow Hubble Space Telescope image of O+ emission Roessler et al. 1997 MHD model of Io interaction - prediction of O+ emission excited by electron impactLinker & McGrath 1998

36. Io Plasma Torus - ground-based telescope S+ Source of plasma = 1 ton of sulfur and oxygen ions per second Schneider & Trauger

37. Cassini UltraViolet Imaging Spectrometer Larry Esposito, University of Colorado • UV images of the toroidal cloud of ions at Io’s orbit, • The S+ , O+ ions are trapped by Jupiter’s magnetic field. • Jupiter is dark at UV wavelengths. E W brighter = direction of dipole tilt

38. Early Radio Observations & Explanations Radio Beam Dulk (1965) Goldreich & Lyndon-Bell (1969)

39. Io Footprint Aurora The Io Aurora Infrared Ultraviolet - energetic particles bombard atmosphere - ‘wake’ emission extends half way around Jupiter

40. Aurora The aurora is the signature of Jupiter’s attempt to spin up its magnetosphere Main Oval Io footprint + wake G E Clarke et al.

41. Jupiter’s Extended Corona ENAs S, O, H Krimigiset al. 30 Rj Charge exchange of energetic charged particles with neutral clouds around orbits of Io and Europa -> escaping Energetic Neutral Atoms => HUGE clouds Sodium 500 Rj ~ 1/4 A.U. Sodium Mendillo et al.

42. SMall EXplorer mission ~$120M Earth-orbiting UV telescope to observe Io, the torus and Jovian aurora

43. Juno Jupiter Polar Orbiter ~$650M

44. Solar Wind Interaction with a Comet

45. ENERGY TIME Comet Borelly Heavy Ions H+

46. Deep Space 1

47. Pluto & Charon

48. The solar wind interacts with Pluto’s escaping atmosphere like a comet

49. New Horizons 2016 Thank you!