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A Whole-Heliosphere View of the Solar Wind Hale Lecture American Astronomical Society 5/24/2010 Marcia Neugebauer University of Arizona

A Whole-Heliosphere View of the Solar Wind Hale Lecture American Astronomical Society 5/24/2010

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A Whole-Heliosphere View of the Solar Wind Hale Lecture American Astronomical Society 5/24/2010. Marcia Neugebauer University of Arizona. The Things that Happen to the Solar Wind After it Leaves the Sun. A Better Title:. The Complex Solar Atmosphere. - PowerPoint PPT Presentation

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Page 1: A Whole-Heliosphere View of the Solar Wind Hale Lecture American Astronomical Society 5/24/2010

A Whole-Heliosphere View of the Solar Wind

Hale LectureAmerican Astronomical Society

5/24/2010

Marcia NeugebauerUniversity of Arizona

Page 2: A Whole-Heliosphere View of the Solar Wind Hale Lecture American Astronomical Society 5/24/2010

A Better Title:

The Things that Happen to the Solar Wind After it Leaves the Sun

Page 3: A Whole-Heliosphere View of the Solar Wind Hale Lecture American Astronomical Society 5/24/2010

The Complex Solar Atmosphere

Page 4: A Whole-Heliosphere View of the Solar Wind Hale Lecture American Astronomical Society 5/24/2010

The Sun creates both slow and fast solar wind

Page 5: A Whole-Heliosphere View of the Solar Wind Hale Lecture American Astronomical Society 5/24/2010

But, it’s a complicated process

Page 6: A Whole-Heliosphere View of the Solar Wind Hale Lecture American Astronomical Society 5/24/2010

Model of open and closed field lines

(Wang et al., 2007)

Page 7: A Whole-Heliosphere View of the Solar Wind Hale Lecture American Astronomical Society 5/24/2010

The Source-Surface Model

(Cravens, 1997)

Page 8: A Whole-Heliosphere View of the Solar Wind Hale Lecture American Astronomical Society 5/24/2010

Major Processes in the Solar Wind

• Expansion• Collision• Reconnection• Pickup (mass loading)

• All of which leads to: – Turbulence– The interstellar medium

Page 9: A Whole-Heliosphere View of the Solar Wind Hale Lecture American Astronomical Society 5/24/2010

Expansion

Page 10: A Whole-Heliosphere View of the Solar Wind Hale Lecture American Astronomical Society 5/24/2010

First Adiabatic Invariant(Conservation of Magnetic Moment )

= mw2/2B T/B = constant

As B , expect T , and T||/ T

Page 11: A Whole-Heliosphere View of the Solar Wind Hale Lecture American Astronomical Society 5/24/2010

Magnetic moment versus distance

(Tu, 1988)

Magnetic Moment versus Distance from Sun

Page 12: A Whole-Heliosphere View of the Solar Wind Hale Lecture American Astronomical Society 5/24/2010

Tperp/Tpar vs βpar for protons < 600 /V km s

Contours of max growth rate inωcp

Proton cyclotron

Parallelfirehose

Mirror instability

Obliquefirehose

(Hellinger et al., 2009)

Page 13: A Whole-Heliosphere View of the Solar Wind Hale Lecture American Astronomical Society 5/24/2010

Proton Distribution functions

(Marsch et al., 1981)

Dis

tanc

e fr

om S

un -

->

Solar wind speed -->

Page 14: A Whole-Heliosphere View of the Solar Wind Hale Lecture American Astronomical Society 5/24/2010

The Strange Behavior of Alpha Particles

• Abundance highly variable• na/np = 0 - .03 in slow wind (~0 at HCS)• na/np = .04-.05 in fast wind• Greatly enhanced in CMEs (up to 0.40!)

• Hotter than protons• Ta/Tp = 4 to 6 in fast wind• Approaches isothermal in slow wind

• Faster than protons• Vap up to 100 km/s in fast wind • Vap -> 0 in dense, slow wind

• Anisotropic and double peaked

Page 15: A Whole-Heliosphere View of the Solar Wind Hale Lecture American Astronomical Society 5/24/2010

Vap vs Distance in Fast Wind

(Neugebauer et al., 1996)

Page 16: A Whole-Heliosphere View of the Solar Wind Hale Lecture American Astronomical Society 5/24/2010

Collision

Page 17: A Whole-Heliosphere View of the Solar Wind Hale Lecture American Astronomical Society 5/24/2010

Magnetized Plasmas Don’t Easily Mix

Page 18: A Whole-Heliosphere View of the Solar Wind Hale Lecture American Astronomical Society 5/24/2010

Note Boundaries Between Winds from Streamers & Coronal Holes

Page 19: A Whole-Heliosphere View of the Solar Wind Hale Lecture American Astronomical Society 5/24/2010

(Gosling et al., 1978)

Some Stream Interfaces are Stable over Many AU

Page 20: A Whole-Heliosphere View of the Solar Wind Hale Lecture American Astronomical Society 5/24/2010

Tangential discontinuities between plasmas fromdifferent sources

Also called the heliospheric current sheet

Heliospheric Current Sheets, Embedded in the Slow Wind, are Also Stable

Solar Maximum Solar MinimumDeclining Activity

Page 21: A Whole-Heliosphere View of the Solar Wind Hale Lecture American Astronomical Society 5/24/2010

Result of the Solar Dipole Tilt(Ballerina Skirt)

(Jokipii & Thomas, 1981)

Page 22: A Whole-Heliosphere View of the Solar Wind Hale Lecture American Astronomical Society 5/24/2010

Solar Rotation Creates Corotating Interaction Regions

(Pizzo, 1978)

Page 23: A Whole-Heliosphere View of the Solar Wind Hale Lecture American Astronomical Society 5/24/2010

Signatures of a CIR at

~5 AU

(Lazarus et al., 1999)

SI at density drop

HCS on Day 138

Page 24: A Whole-Heliosphere View of the Solar Wind Hale Lecture American Astronomical Society 5/24/2010

Coronal Mass Ejections

Page 25: A Whole-Heliosphere View of the Solar Wind Hale Lecture American Astronomical Society 5/24/2010

Interplanetary CMEs

(Richardson, 1997)

Page 26: A Whole-Heliosphere View of the Solar Wind Hale Lecture American Astronomical Society 5/24/2010

Interaction Regions at Solar Max and Min

Page 27: A Whole-Heliosphere View of the Solar Wind Hale Lecture American Astronomical Society 5/24/2010

Evolution of Interaction

regions from

1 to 60 AU

Formation of MIRs

(Wang & Richardson, 2003)

Page 28: A Whole-Heliosphere View of the Solar Wind Hale Lecture American Astronomical Society 5/24/2010

Ecliptic plane view of pileup out to 100 AU

Page 29: A Whole-Heliosphere View of the Solar Wind Hale Lecture American Astronomical Society 5/24/2010

Effect of GMIRs on Cosmic Rays

(Burlaga et al., 2003)

Page 30: A Whole-Heliosphere View of the Solar Wind Hale Lecture American Astronomical Society 5/24/2010

Anti-Correlation of Sunspots and Cosmic Rays

Page 31: A Whole-Heliosphere View of the Solar Wind Hale Lecture American Astronomical Society 5/24/2010

Reconnection

Page 32: A Whole-Heliosphere View of the Solar Wind Hale Lecture American Astronomical Society 5/24/2010

Petschek Reconnection Mechanism

(Gosling, 2005)

Page 33: A Whole-Heliosphere View of the Solar Wind Hale Lecture American Astronomical Society 5/24/2010

Reconnection Exhaust Fans

(Gosling, 2010)

Bifurcated structure

Opposite V//B

Decreased B, Increased V, T

Observed even for small angle changes

Created by turbulence?

Page 34: A Whole-Heliosphere View of the Solar Wind Hale Lecture American Astronomical Society 5/24/2010

Pickup

Page 35: A Whole-Heliosphere View of the Solar Wind Hale Lecture American Astronomical Society 5/24/2010

Pick-up is sometimes associated with

Mass Loading

Page 36: A Whole-Heliosphere View of the Solar Wind Hale Lecture American Astronomical Society 5/24/2010

Non-Solar Sources of Solar Wind Ions

• Atoms and ions– Interstellar medium– Dust– Comets– Planets

• Dust– Comets and Asteroids– Interstellar medium– Jupiter

Page 37: A Whole-Heliosphere View of the Solar Wind Hale Lecture American Astronomical Society 5/24/2010

The Pick-up Process

B

U

In solar-wind frame In inertial frame

Photoionization adds mass to wind.

Charge exchange creates fast neutral and slow ion.

Both processes provide drag on wind.

Page 38: A Whole-Heliosphere View of the Solar Wind Hale Lecture American Astronomical Society 5/24/2010

Proton Spectrum with Pickup Ions

(Gloeckler et al., 2001)

Page 39: A Whole-Heliosphere View of the Solar Wind Hale Lecture American Astronomical Society 5/24/2010

Inner Source of Pick-up Ions

(Gloeckler et al., 2001)

Page 40: A Whole-Heliosphere View of the Solar Wind Hale Lecture American Astronomical Society 5/24/2010

High-Energy Tails of H and He

(Gloeckler, 2003)

Page 41: A Whole-Heliosphere View of the Solar Wind Hale Lecture American Astronomical Society 5/24/2010

Effect of Pickup Ions on the Wind

• Photoionization adds mass • Charge exchange may conserve mass

– Results in a fast neutral atom and a slow ion

• Both processes result in:– Acceleration of slow ions up to Vsw – Drag– Hot ions with Vth Vsw

Page 42: A Whole-Heliosphere View of the Solar Wind Hale Lecture American Astronomical Society 5/24/2010

Slow-Down of Solar Wind due to Pick-up Ions

Page 43: A Whole-Heliosphere View of the Solar Wind Hale Lecture American Astronomical Society 5/24/2010

Turbulence

Page 44: A Whole-Heliosphere View of the Solar Wind Hale Lecture American Astronomical Society 5/24/2010

OGO 5Density fluctuations(Neugebauer, 1976)

f/fpg

Helios 2Field vector spectra

(Bruno & Carbone, 2005)

Power Spectra

Page 45: A Whole-Heliosphere View of the Solar Wind Hale Lecture American Astronomical Society 5/24/2010

2-D Simulation of MHD Turbulence

(Greco et al., 2010)

Field lines + Current density (gray shade)

Current sheets generated locally

Reconnection heats plasma

Page 46: A Whole-Heliosphere View of the Solar Wind Hale Lecture American Astronomical Society 5/24/2010

The End of the Road

(Approach to Alaska’s Bridge to Nowhere)

Page 47: A Whole-Heliosphere View of the Solar Wind Hale Lecture American Astronomical Society 5/24/2010

Interaction with the Interstellar Medium

Page 48: A Whole-Heliosphere View of the Solar Wind Hale Lecture American Astronomical Society 5/24/2010

Model of Outer Heliosphere

Page 49: A Whole-Heliosphere View of the Solar Wind Hale Lecture American Astronomical Society 5/24/2010

Anomalous Cosmic Rays at TS and in Heliosheath

(Courtesy A. Cummings, 2010)

Page 50: A Whole-Heliosphere View of the Solar Wind Hale Lecture American Astronomical Society 5/24/2010

“The Ribbon”

Page 51: A Whole-Heliosphere View of the Solar Wind Hale Lecture American Astronomical Society 5/24/2010

Summary

• A lot of interesting physics in the solar wind• Several unsolved issues

– Turbulent processes– Relaxation of anisotropic and multi-beams– Physics of high-energy tails– Acceleration of ACR– Prevalence of reconnection– Stability/sources of discontinuities

• Applications to many other astrophysical settings