What is New in the Outer
Heliosphere?: Voyager andIBEXMarty Lee

Durham, New Hampshire
USA1

Our Local Interstellar Environment

From E. Möbius

Pogorelov et al., 2008

Plasma & Neutral Parameters
R = 1 AUR = 100 AU

n p  5 cm-3

3n p 1 10 cm

n p  0.05 cm

Vsw  400 km/s

Vsw  300 km/s

VISM  23(?) km/s

B0  5 105 G

B0  0.3 106 G

B0  3106 (?)GVA  40 km/s 3n He  0.015 cm
LISM
3-3


VA  20 km/s
-3n H  0.1cm

VA  22(?) km/s
-3n H  0.2 cm

n He  0.015 cm3n He  0.015 cm34

Voyagers 1&2: Still Exploring!

5

Voyager Trajectories

15-Apr-13

AIAC12

Fig. by J. Richardson
6

IBEX Spacecraft■ Simple sun-pointed spinner (4 rpm)
■ Two huge aperture single pixel ENA cameras:● IBEX-Lo (~10 eV to 2 keV)
● IBEX-Hi (~300 eV to 6 keV)
E. Möbius, UNH SSC, for the IBEX Team

Colloquium Wesleyan University,

Termination Shock is Special✪✪✪✪✪✪✪✪plasma✪pickup ionneutralCR8

Adventures in the Outer Heliosphere•Where is the Shock and ACRs?
•ISM Gas Parameters•No Heliospheric Bow Shock•First Measurement of Primary ISM H•“Hydrogen Deflection Plane” (Lallement)•The IBEX “Ribbon”•Heliosheath Vr ~ 0•The “Heliocliff”•First Measurement of Low-Energy GCRs

Voyager 1
Ions

Decker et al., 2005

Stone et al., 2008

Termination Shock
Plasma Data
At Voyager 2

Richardson et al., 2008

Pickup Ion Distribution in SWvy0Vswvx

Voyager 1 Downstream Spectra

Stone et al., 2005

Stone et al., 2005
15

Current Sheets & Reconnection

Pogorelov et al., 200916

Particle acceleration
Pumping Mechanism

Fisk & Gloeckler 2010

Particles are accelerated by a series ofadiabatic compressions and expansions,in which the particles can escape from acompression region.

Island merging & contraction

Fermo, Drake, Swisdak, 2010

Particles are accelerated by merging andContracting islands.

Ideas of Particle Acceleration(cont.)

Credit: NASA

Diffusive Shock Acceleration

The Blunt Termination Shock

McComas and Schwadron, 2006

Blunt Shock:
2D Simulation for ACR energies

TS is offset circe,
small cross field diffusion:
η=0.02
ACR flux
increasesinto theHeliosheath
• V-2

• V-1

Spectrum
graduallyunfolds

Kota, 2010

(New) Puzzles and Controversies•Where is the Shock and ACRs?
•ISM Gas Parameters•No Heliospheric Bow Shock•First Measurement of Primary ISM H•“Hydrogen Deflection Plane” (Lallement)•The IBEX “Ribbon”•Heliosheath Vr ~ 0•The “Heliocliff”•First Measurement of Low-Energy GCRs

IBEX
Observes
He and H

23

Flow Latitude
Distribution

24

FlowLongitude
Distribution

25

Basic Equations (μ<1 and μ>1)32f (v,, )(V E / n)  ( t)3/2 exp t 1  v2  2r 1 (1  )  vISM
 2vISM [v2  2r 1 (1  )]1/2  cos  cos  cos  sin  [cos  cos sin   sin  sin ] exp  r(vsin )1 cos1 (cos  )



1/22
122 3
22
1cos    1 rv (1  ) sin   r v (1  ) v  2r (1  ) sin2  cos 
2

1/2
1/2
2222


rvrvrvrv
22sin    sin cos   2 sin  1 sin  1    1   1  (1  ) 2  [rv2 (1  )1 1]2 sin2   cos2 Sun to Earth Frame
V cos  V 'cos 'V sin sin  V 'sin 'sin 'V sin cos  V 'sin 'cos 'VE '/ Helium Integrated Intensity
'   / 2t  0.03
vISM  0.75

00  5IBEX Frame /Peak in Latitude
3E2f (v,, )(V / n)  ( t)3/2 exp t 1  v2  2  vISM
 2vISM (v2  2)1/2  cos  cos  sin  sin  cos(   )   2lnv' v1 cos1 (v2 1)1 2000v(cos
sin)v
sin(
00z
scEsc0) sc  
(v0 1) | sin  |(v0 1)(v02  2)1/2| sin  |1
Independent of Ionization Rate

Best ISM He ParametersISM  79.0  0.47

ISM  75.4  0.4 ISM  4.98  0.21

Witte, 2004

VISM  23.2  0.3 kms

1TISM  6300  390 K
McComas et al., 201232

(New) Puzzles and Controversies•Where is the Shock and ACRs?
•ISM Gas Parameters•No Heliospheric Bow Shock•First Measurement of Primary ISM H•“Hydrogen Deflection Plane” (Lallement)•The IBEX “Ribbon”•Heliosheath Vr ~ 0•The “Heliocliff”•First Measurement of Low-Energy GCRs

No Bow Shock!

McComas etal., 201234

(New) Puzzles and Controversies•Where is the Shock and ACRs?
•ISM Gas Parameters•No Heliospheric Bow Shock•First Measurement of Primary ISM H•“Hydrogen Deflection Plane” (Lallement)•The IBEX “Ribbon”•Heliosheath Vr ~ 0•The “Heliocliff”•First Measurement of Low-Energy GCRs

Interstellar
HydrogenSchwadron etal., 201336

Hydrogen
Speed,Temperature and λSchwadron etal., 201337

Radiation Pressure on H

Schwadron etal., 2013

38

(New) Puzzles and Controversies•Where is the Shock and ACRs?
•ISM Gas Parameters•No Heliospheric Bow Shock•First Measurement of Primary ISM H•“Hydrogen Deflection Plane” (Lallement)•The IBEX “Ribbon”•Heliosheath Vr ~ 0•The “Heliocliff”•First Measurement of Low-Energy GCRs

Lyman-αBackscatter

Lallement et al., 2005
40

Origin of Secondaries

Primary and Secondary H

42
Pogorelov et al., 2008

(New) Puzzles and Controversies•Where is the Shock and ACRs?
•ISM Gas Parameters•No Heliospheric Bow Shock•First Measurement of Primary ISM H•“Hydrogen Deflection Plane” (Lallement)•The IBEX “Ribbon”•Heliosheath Vr ~ 0•The “Heliocliff”•First Measurement of Low-Energy GCRs

IBEX Reveals the “Ribbon”

The View with IBEX - 2009

SWRI/Adler Planetarium

Secondary ENAs as Source for the IBEX RibbonHeerikhuisen et al., 200911/29/2013

ASTRONUM 2012, Hawaii

47

(New) Puzzles and Controversies•Where is the Shock and ACRs?
•ISM Gas Parameters•No Heliospheric Bow Shock•First Measurement of Primary ISM H•“Hydrogen Deflection Plane” (Lallement)•The IBEX “Ribbon”•Heliosheath Vr ~ 0•The “Heliocliff”•First Measurement of Low-Energy GCRs

Voyager in the Transition Layer• Zero radial outflow !
• Increase of tangential speed

Krimigis et al., 2011

Time-Dependent Heliosheath

Pogorelov et al., 201250

(New) Puzzles and Controversies•Where is the Shock and ACRs?
•ISM Gas Parameters•No Heliospheric Bow Shock•First Measurement of Primary ISM H•“Hydrogen Deflection Plane” (Lallement)•The IBEX “Ribbon”•Heliosheath Vr ~ 0•The “Heliocliff”•First Measurement of Low-Energy GCRs

Voyager at the Heliopause?

Voyager 1, 2012/183-2013/98: Galactic cosmic rays enter the high-B
regions, while low-energy heliosheath particles leave via magnetic
connection to LISM

15-Apr-13

AIAC1253

Voyager 1: Heliosheath particles escape, GCRs enter & B
increases

15-Apr-13

AIAC1254

Voyager 1: Angular distributions of protons 3.4-17.6 MeV(1-d avg.) 2012/183-330

15-Apr-13

AIAC1255

Voyager in the Heliosheath

Burlaga et al., 2013 Image credit: NASA/JPLCaltech/GSFC/University of Delaware

Magnetic Field Observations
Conclusions:•Increase of the magnetic
field magnitude.
•NO change in the magnetic
field orientation.
Parker Spiral magnetic field

Burlaga et al., 2013 Image credit: NASA/JPLCaltech/GSFC/University of Delaware(New) Puzzles and Controversies•Where is the Shock and ACRs?
•ISM Gas Parameters•No Heliospheric Bow Shock•First Measurement of Primary ISM H•“Hydrogen Deflection Plane” (Lallement)•The IBEX “Ribbon”•Heliosheath Vr ~ 0•The “Heliocliff”•First Measurement of Low-Energy GCRs

The Current Picture of theHeliosphere

McComas et al. 2012