Overview of CMSO

Center for Magnetic Self-Organization in Laboratory and Astrophysical Plasmas

S. Prager May, 2006

Outline

• Physics topics • Participants • Physics goals and highlights • Educational outreach • Management structure • Funding

Magnetic self-organization

energy source nonlinear plasma phy sics

se lf - o r g aniz at io n

large-scale st ruct ure magnet ic inst abilit ies

The nonlinear plasma physics energy source dy namo magnet ic reconnect ion angular moment um t ransport magnet ic chaos and t ransport magnet ic helicit y conserv at ion ion heat ing

se lf - o r g aniz at io n

large-scale st ruct ure magnet ic inst abilit ies

Magnetic self-organization in the lab

.04

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ion temperature

T ion

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0 –2 C 4+ –1 0 1

magnetic fluctuations (reconnection) dynamo energy transport momentum transport

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ion heating

CMSO goal:

understand plasma physics needed to solve key laboratory and astrophysical problems

• linking laboratory and astrophysical scientists • linking experiment, theory, computation

Original Institutional Members Princeton University The University of Chicago The University of Wisconsin Science Applications International Corp Swarthmore College Lawrence Livermore National Laboratory ~25 investigators, ~similar number of postdocs and students ~ equal number of lab and astrophysicists

With New Funded Members Princeton University The University of Chicago The University of Wisconsin Science Applications International Corp Swarthmore College Lawrence Livermore National Laboratory Los Alamos National Laboratory (05) University of New Hampshire (05) ~ 30 investigators, ~similar number of postdocs and students ~ equal number of lab and astrophysicists

Cooperative Agreements (International) Ruhr University/Julich Center, Germany(04) Torino Jet Consortium, Italy (05)

Experimental facilities

Facilit y

MST ( Madison S ymme tr ic To rus) MRX ( Magnet ic Reconnect ion Exp t ) SSPX ( St eady Stat e Spheromak Exp t ) SSX ( Swarth more Spheromak Exp t ) MRI experiment

Inst it uti on

Universit y of Wisconsin Princet on Universit y Lawrence Livermore Nat ional Lab Swart hm ore College Princet on Universit y

Descript ion

Reversed Field Pinc h Mergi ng Plasmas Sphero ma k Mergi ng Plasmas Flow ing liquid gallium •yields range of topologies and critical parameters •Joint experiments and shared diagnostics

MRX: Magnetic Reconnection Experiment (Princeton) SSX: Swarthmore Spheromak Experiment SSPX: Sustained Spheromak Physics Experiment (LLNL) MST: Madison SymmetricTorus (Wisconsin)

MRX

Inductively produced plasmas, Spheromak or annular plasmas Locailzed reconnection at merger

SSX

Electrostatically - produced spheromaks (by plasma guns) Two spheromaks reconnect and merge

SSPX

Electrostatically - produced spheromak

MST

Reversed field pinch

Liquid gallium MRI experiment (Princeton)

To study the magnetorotational instability

Code

NEK 5000 Li2 Major Computational Tools

Inst it ution

Universit y of Chicago Los A lamos

Descript ion

Spect ral f init e elements incompressible resistiv e MHD ( Any geomet ry ) Nonlinear, 3 D, ideal HD/ MHD, Cart esian, Cylind rical, Spherical DEBS Universit y of Wisconsin Universit y of Chicago SAIC, U. Wisconsin NIMROD Multi -instit uti onal (W isconsin, SAIC, Los A lamos) VPIC Los A lamos Third ord er hyb rid, essenti ally non oscillat ory ( ENO) isoth erm al code f or compressible MHD Fully spect ral, incompressible, resistiv e MHD ( slab or t riply periodic) Nonlinear, 3 D, resistiv e MHD , cylind rical geo met ry Nonlinear, 3 D, resistiv e, t wo -f luid , t oro idal g eomet ry Nonlinear, 3 D relat ivi sti c PIC •Not an exhaustive list •Codes built largely outside of CMSO •Complemented by equal amount of analytic theory

Sample Physics Highlights • New or emerging results • Mostly where center approach is critical We are pursuing much of the original plans, but new investigations have also arisen (plans for next 2 years discussed later)

Reconnection

• Two-fluid Hall effects • Reconnection with line tying • Effects of coupled reconnection sites • Effects of lower hybrid turbulence

not foreseen in proposal

Hall effects on reconnection

• Identified on 3 CMSO experiments (MRX, SSX, MST) • Performed quasilinear theory • Will study via two-fluid codes (NIMROD, UNH) and possibly via LANL PIC code

Observation of Hall effects

Observed quadrupole B component, MRX SSX QuickTime™ and a TIFF (LZW) decompressor are needed to see this picture.

radius also observed in magnetosphere

Reconnection with line-tying • Studied analytically (UW, LANL) and computationally(UW) • Compare to non-CMSO linear experiments • Features of periodic systems survive (e.g.,large, localized currents)

Linear theory for mode resonance in cylinder

v  periodic line-tied radius

radius

Effects of multiple, coupled reconnections Many self-organizing effects in MST occur ONLY with multiple reconnections

Effects of multiple, coupled reconnections Many self-organizing effects in MST occur ONLY with multiple reconnections core reconnection only core reconnection multiple reconnections core edge reconnection edge

•Applies to magnetic energy release, dynamo, momentum transport, ion heating •Related to nonlinear mode coupling •Might be important in astrophysics where multiple reconnections may occur (e.g., solar flare simulations of Kusano)

Lower hybrid turbulence Detected in MRX Magnetic fluctuations QuickTime™ and a TIFF (LZW) decompressor are needed to see this picture.

0 10 f(MHz) •Reconnection rate  turbulence amplitude; •Instability theory developed, •May explain anomalous resistivity

Lower hybrid turbulence Detected in MRX Magnetic fluctuations QuickTime™ and a TIFF (LZW) decompressor are needed to see this picture.

E Similar to turbulence in magnetosphere (Cluster) B QuickTime™ and a TIFF (LZW) decompressor are needed to see this picture.

QuickTime™ and a TIFF (LZW) decompressor are needed to see this picture.

0 10 f(MHz) •Reconnection rate ~ turbulence amplitude; •Instability theory developed, •May explain anomalous resistivity

Momentum Transport

radial transport of toroidal momentum rotation momentum transport In accretion disks, solar interior, jets, lab experiments, classical viscosity fails to explain momentum transport

Leading explanation in astrophysics MHD instability Flow-driven (magnetorotational instability) momentum transported by j x b and  v .

 v Leading explanation in lab plasma resistive MHD instability momentum transported by j x b and  v .

 v

Momentum Transport Highlights

• MRI in Gallium: experiment and theory • MRI in disk corona: computation • Momentum transport from current-driven reconnection

MRI in Gallium

• Experiment (Princeton) hydrodynamically stable, ready for gallium V  --- Couette flow + end caps rotate r radius •Simulation (Chicago) underway QuickTime™ and a TIFF (LZW) decompressor are needed to see this picture.

MRI in disk corona • Investigate effects of disk corona on momentum transport; possible strong effect • Combines idea from Princeton, code from SAIC

initial state: flux dipole

...after a few rotations

Momentum transport from current-driven reconnection experiment Requires multiple tearing modes (nonlinear coupling)

Theory and computation of Maxwell stress in MHD  quasilinear theory for one tearing mode ˜  resonant surface r   ˜  computation for multiple, interacting modes

An effect in astrophysical plasmas?

reconnection and flow is ubiquitous raises some important theoretical questions (e.g., effect of nonlinear coupling on spatial structure)

Ion Heating

Ion heating in solar wind

thermal speed km/s QuickTime™ and a TIFF (LZW) decompressor are needed to see this picture.

r/R

sun Strong perpendicular heating of high mass ions

Ion heating in lab plasma

Observed during reconnection in all CMSO experiments

T

i

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t = +0.50 ms MST QuickTime™ and a TIFF (LZW) decompressor are needed to see this picture.

t = -0.25 ms radius

Conversion of magnetic energy to ion thermal energy ~ 10 MW flows into the ions

change in ion thermal energy (J) reconnected magnetic field energy (J) MRX

Magnetic energy can be converted to Alfvenic jets magnetic energy SSX Energetic ion flux QuickTime™ and a TIFF (LZW) decompressor are needed to see this picture.

time (  s)

 Ions heated only with core and edge reconnection core edge TIFF (LZW) decompressor are needed to see this picture.

MST core reconnection edge reconnection

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time (ms)

What is mechanism for ion heating?

• Still a puzzle • Theory of viscous damping of magnetic fluctuations has been developed

Magnetic chaos and transport

Magnetic turbulence Transport in chaotic magnetic field

Magnetic chaos and transport

Magnetic turbulence • Star formation • Heating via cascades • Scattering of radiation • Underlies other CMSO topics Transport in chaotic magnetic field • Heat conduction in galaxy clusters (condensation) • Cosmic ray scattering

Magnetic turbulence

• Properties of Alfvenic turbulence • Intermittency in magnetic turbulence • Comparisons with turbulence in experiments Sample results: Intermittency explains pulsar pulse width broadening, Observed in kinetic Alfven wave turbulence computation QuickTime™ and a TIFF (LZW) decompressor are needed to see this picture.

Measurements underway in experiment for comparison

Transport in chaotic field Experiment measure transport vs gyroradius in chaotic field

Transport in chaotic field Experiment measure transport vs gyroradius in chaotic field Result Small gyroradius (electrons): large transport Large gyroradius (energetic ions): small transport Ion orbits well-ordered Transport measured via neutron emission from energetic ions produced by neutral beam injection Possible implications for relativistic cosmic ray ions

The Dynamo

Why is the universe magnetized?

• Growth of magnetic field from a seed • Sustainment of magnetic field • Redistribution of magnetic field

Why is the universe magnetized?

• Growth of magnetic field from a seed primordial plasma • Sustainment of magnetic field e.g., in solar interior in accretion disk • Redistribution of magnetic field e.g., solar coronal field extra-galactic jets

The disk-jet system

Field sustained (the engine) Field produced from transport

CMSO Activity

• Theoretical work on all problems the role of turbulence on the dynamo, flux conversion in jets, • Lab plasma dynamo effect: field transport, with physics connections to growth and sustainment

Abstract dynamo theory Small-scale field generation (via turbulence) Computation: dynamo absent at low  /  Theory: dynamo present at high R m Large-scale field generation No dynamo via homogeneous turbulence, Large-scale flows sustains field

Magnetic field fluctuations generated by turbulent convection Dynamo action driven by shear and magnetic buoyancy instabilities.

MHD computation of Jet production Magnetically formed jet |J| contours QuickTime™ and a TIFF (LZW) decompressor are needed to see this picture.

MHD computation of Jet evolution Magnetically formed jet |J| contours QuickTime™ and a TIFF (LZW) decompressor are needed to see this picture.

helical fields develop in jet QuickTime™ and a TIFF (LZW) decompressor are needed to see this picture.

When kink unstable, flux conversion B  -> B z Similarities to experimental fields

Dynamo Effect in the Lab

in experiment

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Hall dynamo is significant

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Hall dynamo

(theory significant)

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Hall dynamo is significant

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Hall dynamo experiment:

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Questions for the lab plasma, relevant to astrophysics • At what conditions (and locations) do two-fluid and MHD dynamos dominate?

• Is the final plasma state determined by MHD, with mechanism of arrival influenced by two-fluid effects?

• Is the lab alpha effect, based on quasi-laminar flows, a basis for field sustainment (possibly similar to conclusion from computation for astrophysics)

CMSO Educational Outreach

•Highlight is Wonders of Physics program •Supported by CMSO and DOE (50/50) •Established before CMSO, expanded in quantity and quality

~ 150 traveling shows/yr all 72 Wisconsin counties, plus selected other states QuickTime™ and a TIFF (LZW) decompressor are needed to see this picture.

~ 6 campus shows

Center Organization

Topical Coordinators

each pair = 1 lab, 1 astro person • Reconnection • Momentum transport • Dynamo • Ion Heating • Chaos and transport • Helicity • Educational outreach Craig, Li Yamada, Zweibel Cattaneo, Prager Fiksel, Schnack Malyshkin, Terry Ji, Kulsrud Reardon, Sprott

CMSO Steering Committee

F. Cattaneo H. Ji S. Prager D. Schnack C. Sprott P. Terry M. Yamada E. Zweibel meets weekly by teleconference

CMSO Program Advisory Committee

S. Cowley (Chair) P. Drake W. Gekelman R. Lin G. Navratil E. Parker A. Pouquet D. Ryutov UCLA University of Michigan UCLA UC - Berkeley Columbia University University of Chicago NCAR, Boulder, CO Lawrence Livermore National Lab

CMSO International Liaison Committee

M. Berger A. Burkert K. Kusano P. Martin Y. Ono M. Velli N. Weiss University College, London, UK The University of Munich, Germany Hiroshima University, Japan Consorzio RFX, Padua, Italy Tokyo University, Japan Universita di Firenze, Italy Cambridge University, UK

CMSO Meetings Sept, 03 Sept, 03 Ion heating/chaos (Chicago) Reconnection/momentum (Princeton) Oct, 03 Dynamo (Chicago) Nov, 03 General meeting (Chicago) June,04Hall dynamo and relaxation (Princeton) Aug, 04 General meeting (Madison) Sept, 04 PAC meeting (Madison) Oct, 04 Reconnection (Princeton) Jan, 05 Video conference of task leaders March, 05 General meeting (San Diego) April, 05 June, 05 June, 05 Dynamo/helicity meeting (Princeton) Intermittency and turbulence (Madison) Experimental meeting (Madison) Oct, 05 General meeting (Princeton) Nov, 05 PAC meeting (Madison) Jan, 06 Winter school on reconnection (Los Angeles, w/CMPD) March, 06 June, 06 Line-tied reconnection (Los Alamos) Workshop on MSO (Aspen, with CMPD)) Aug, 06 General meeting (Chicago)

• NSF • DOE • LANL

Budget

$2.25M/yr for five years ~$0.4M to PPPL ~$0.1M to LLNL ~$0.15M to UNH all facility and base program support ~$0.34M

CMSO is a partnership between NSF and DOE

Summary

•CMSO has enabled many new, cross-disciplinary physics activities (and been a learning experience) •New linkages have been established (lab/astro, expt/theory, expt/expt) •Many physics investigations completed, many new starts •The linkages are strong, but still increasing, the full potential is a longer-term process than 2.5 years