1. Nature, Distribution and Evolution of Solar Wind Turbulence throughout the Heliosphere W. H. Matthaeus Bartol Research Institute, University of Delaware
Collaborators: P. Dmitruk, S. Oughton, L. Milano, D. Mullan, G. Zank,
R. Leamon, C Smith, D. Montgomery, J. Bieber, A. Burger, S. Parhi
Seminar presented at Southwest Research Institute, December 5, 2003

2. The solar wind orginates in the dynamically active (turbulent) chromosphere and corona SOHO spacecraft
UV spectrograph: EIT 340 A
White light coronagraph: LASCO C3

3. Large scale features of the solar wind
Plasma outflow, spiral magnetic field
High and low speed streams
North south distorted magnetic dipole
Wavy, equatorial current sheet

4. Large scale features of the Solar Wind: Ulysses
High latitude
Fast
Hot
steady
Comes from coronal holes
Low latitude
slow
“cooler” (40,000 1 AU)
nonsteady
Comes from streamer belt
McComas et al, GRL, 1995

5. Heliospheric turbulence: Applications
Coronal heating
Solar wind heating
Solar modulation of cosmic rays
Spatial diffusion of solar energetic particles
turbulence and “space weather”
Possible influence on large scale heliospheric structure.

6. Interplanetary Alfven waves
Belcher and Davis, 1971

7. “Powerlaws everywhere”
Broadband self-similar spectra are a signature of cascade
Interstellar medium: Armstrong et al
Solar wind
Corona
Diffuse ISM
Geophysical flows
SW at 2.8 AU: Matthaeus and Goldstein
Tidal channel: Grant, Stewart and Moilliet
Coronal scintillation results (Harmon and Coles)

8. Standard powerlaw cascade picture

10. Two-dimensional turbulence and random-convection-driven reconnection

11. Heating the solar wind in the outer heliosphere (> 1 AU)

12. Voyager proton temperatures
Something is heating the solar wind in the outer heliosphere (> 1 AU)
Voyager proton temperatures
Richardson et al, GRL, 1995

13. Phenomenological model for radial evolution of SW turbulence
Transport equations for turbulence energy Z2, energy-containing scale l, and temperature T
effect of large scale wind shear DV ~100 km/sec
wave generation by pickup ions associated with interstellar neutral gas
Anisotropic decay and heating phenomenology
Matthaeus et al, 1996; Zank et al, 1996; Matthaeus et al, PRL, 1999; Smith et al, JGR, 2001; Isenberg et al, 2003

14. Solar Wind Heating
Perpendicular MHD cascade/transport theory accounts for radial evolution from 1 AU to >50 AU
Proton temperature
ADIABATIC
Matthaeus et al, PRL, 1999
Smith et al, JGR 2001
Isenberg et al, 2002

15. Results of turbulence transport theory in outer heliosphere
Turbulence energy
Proton temp.
correlation scale

16. Evolution of Alfvenicity with radial distance

17. Cross helicity/ Alfvenicity
Normalized measure of energy in fluctuations that
propagate counter to or along the large scale magnetic field

18. Decrease of Alfvenicity with heliocentric distance
Helios and Voyager data
Roberts et al, 1987b

19. Helios data
Z+ and Z-
spectra
Marsch and Tu

20. sc tends to increase in time (homogeneous turbulence)
Theory based on Kraichnan 65 ideas: Dobrowolny et al, 1980
3D: Pouquet et al 1986
2D: Matthaeus et al, 1983

21. sc does not always increase!
Stribling and Matthaeus, 1992

22. Velocity shear reduction of cross helicity
observations
simulations
Roberts et al, JGR 1992

23. Expansion  reduction of cross helicity
Linear transport effect
Zhou and Matthaeus, 1988

24. Cross helicity (Alfvenicity) in solar wind
Competition between effects that
-- increase σc: dynamic alignment
-- decrease σc: expansion, shear, pickup ions

25. Transport equations modified for nonzero cross helicity
I. Decay constants
attenuated in energy
and correlation
scale equations.
II. New equation for normalized cross helicity:

26. Cross helicity transport: theory and observations
IMPROVED MODEL:
Transport equation solved in
radius
Boundary conditions and
parameters (density. wind speed
vary with latitude
Include cross helicity

27. Transport and evolution of turbulence including cross helicity and latititude effects
Energy
Correlation scale
Temperature
Cross helicity
Latitude effects

28. Ab Initio theory of the solar modulation of galactic cosmic rays

29. Solar modulation couples cosmic rays and turbulence locally and globally
Modulation code solves Parker transport equation for cosmic ray spectrum throughout heliosphere.
Solutions depend sensitively on diffusion coefficients
(parallel and perpendicular)
 These depend on local turbulence properties
such as magnetic variance and correlation scale.

30. Sample modulation result
Bartol –Potch collaboration
Parhi et al, 2003
CR energy spectrum at 1AU
Radial gradient in ecliptic plane
Latitudinal gradient at 2.1 AU
Simultaneous solution for CRs and turbulence with good agreement with
many observations!

31. Conclusions: We are moving towards understanding the spatial distribution and dynamical evolution of MHD turbulence throughout the heliosphere
Coronal heating
Solar wind evolution
Modulation
Solar energetic particles
Influences on large scale structure and dynamics
SW natural laboratory for study of turbulence as a fundamental physical process
A prototype for astrophysical turbulence
Mediates cross scale couplings
Enhances transport and heating
Couples energetic particles to the plasma
Couplings to Geospace environment
Consequences for upcoming NASA mission
- Magnetospheric Multiscale (MMS)
- L1 Cluster/Constellation/Diamond
- Solar Probe
- Interstellar Probe
Turbulence and energetic particle
observations are now providing
Simultaneous constraints on theory!

32. Waves – Turbulence—Transport
Interplanetary medium shows characteristics of both waves and turbulence
These mediate many dynamical processes in the heliosphere
Need to know:
Source
Dynamics, couplings: local effects
Transport properties– interaction with large scale structure
 distribution of turbulence throughout heliosphere

33. Fine scale activity in the corona
FE IX/X lines, TRACE
Drawings from Coronagraphs (Loucif and Koutchmy, 1989)

34. Low frequency Nearly Incompressible Quasi-2D cascade
Dominant nonlinear activity involves k’s such that
Tnonlinear (k) < TAlfven (k)
Transfer in perp direction, mainly
k perp >> k par

35. Turbulence in the heliosphere