Overview of CMSO Center for Magnetic Self-Organization in by biu27071

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									      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

                              nonlinear
energy source                 plasma phy sics

                             se lf-or g aniz at ion

         large-scale st ruct ure            magnet ic
                                            inst abilit ies
          The nonlinear plasma physics

                          dy namo
                          magnet ic reconnect ion
                          angular moment um t ransport
                          magnet ic chaos and t ransport
                          magnet ic helicit y conserv at ion
energy source             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
                   ˜
                   B~     .04
                                                             magnetic fluctuations
                    b     .02
                   B
                   B(a)
                           0
                                                                (reconnection)

                 flux
toroidal magnetic a2 .07
                   (T)                                              dynamo
                          .06
                          1.5
        heat flux
                  Q       1.0
          (MW/m2)
               (MW /m2) 0.5                                   energy transport
                           0
                          30
          rotation        20
                   V
          (km/s) (km/s)    10
                                                             momentum transport
                            0
                          0.4
   ion temperature
                Tion            C4+
         (keV)            0.2
                 (KeV)                                          ion heating
                           0
                           –2         –1         0       1      2
                                             Time (ms)
                                           time (ms)
 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                         Inst it ution              Descript ion
                 MST                       Universit y of Wisco nsin    Reversed Field Pinch
     ( Madison S ymme tr ic Torus)
                 MRX                         Princet on Universit y       Merging Plasmas
   ( Magnet ic Reconnect ion Exp t )
                SSPX                     Lawrence Livermore Nat ional        Sphero mak
   ( St eady St at e Spheromak Exp t )               Lab
                 SSX                         Swart hmore College          Merging Plasmas
   ( Swarth more Spheromak Exp t )
       MRI experiment                        Princet on Universit y     Flow ing liquid gallium




•yields range of topologies and critical parameters
•Joint experiments and shared diagnostics
 MRX: Magnetic Reconnection         SSX: Swarthmore Spheromak
      Experiment (Princeton)             Experiment




                                    MST: Madison SymmetricTorus
SSPX: Sustained Spheromak Physics
                                            (Wisconsin)
      Experiment (LLNL)
       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
               Major Computational Tools
      Code            Inst it ution                        Descript ion
        NEK        Universit y of Chicago       Spect ral f init e eleme nts
                                                incomp ressible resistiv e MHD ( Any
       5000                                     geomet ry )
        Li2             Los Alamos                  Nonlinear, 3 D, ideal HD/ MHD,
                                                   Cart esian, Cylind rical, Sph erical

                  Universit y of Wisconsin      Third ord er hybrid, essenti ally non-
                                                oscillat ory ( ENO) isoth erm al code
                                                f or comp ressible MHD
                   Universit y of Chicago            Fully spe ct ral, incomp ressible,
                                                resistiv e MHD ( slab or t riply periodic)

       DEBS         SAIC, U. Wisconsin              Nonlinear, 3 D, resistiv e MHD ,
                                                         cylind rical geo me t ry

      NIMROD          Multi -instit uti onal     Nonlinear, 3 D, resistiv e, t wo-f luid ,
               (W isconsin, SAIC, Los Alamos)            t oro idal geomet ry

       VPIC             Los Alamos                   Nonlinear, 3 D relat ivisti 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
                                          not foreseen in
• Effects of coupled reconnection sites   proposal


• Effects of lower hybrid turbulence
          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




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                                            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        multiple
                                         reconnections
                core reconnection        core



                                        edge
                edge reconnection
•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


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   0                       10            f(MHz)

•Reconnection rate  turbulence amplitude;
•Instability theory developed,
•May explain anomalous resistivity
                            Lower hybrid turbulence
   Detected in MRX                                    Similar to turbulence in
                                                      magnetosphere (Cluster)
       Magnetic fluctuations                      E
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                                                  B
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   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
                            
current-driven (tearing 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
                                                                    --- Couette flow
                                                                     + diff. endcaps flow
                                                                          Couette
• Experiment (Princeton)                                             + end caps rotate
                                                                        with outer cyl.
                                                                          experiment
  hydrodynamically stable,      V




                                v
  ready for gallium


                                                                         r
                                                                                    radius


 •Simulation (Chicago)
 underway                                QuickTime™ and a
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                           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               computation for multiple,
    one tearing mode                   interacting modes
           j ˜
           ˜B
              resonant              j ˜
                                    ˜B
               surface


                       r
                         



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


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                              r/Rsun

Strong perpendicular heating of high mass ions
            Ion heating in lab plasma
  Observed during reconnection in all CMSO experiments


 Ti
(eV)                                                           MST
               t = +0.50 ms


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              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)
                                                          MRX




                  reconnected magnetic field energy (J)
Magnetic energy can be converted to Alfvenic
                   jets

magnetic                                      SSX
energy

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Energetic   are needed to see this picture.
 ion flux



                       time (s)
Ions heated only with core and edge reconnection


                                             MST
                                                    core
   ˜
   B               core
                  QuickTime™ and a edge
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                                                    reconnection
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                                                   reconnection




   Ti
  (eV)            QuickTime™ and a
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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


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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 produced
Field sustained (the   from transport
engine)
                    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 Rm




                                                      Magnetic field fluctuations
Large-scale field generation                          generated by turbulent convection

   No dynamo via homogeneous turbulence,
   Large-scale flows sustains field



                                   Dynamo action driven by
                                   shear and magnetic
                                   buoyancy instabilities.
           MHD computation of Jet production
Magnetically formed jet

|J| contours
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                MHD computation of Jet evolution
Magnetically formed jet

 |J| contours
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helical fields
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 When kink unstable, flux conversion B -> Bz
 Similarities to experimental fields
     Dynamo Effect in the Lab
in experiment                   E  j
            2.0

                               E ||
            1.5
                                      E||
          1.0
      V/m
            0.5
                           neo
                          j|| J||
                               (Zeff = 2)
            0.0


            -0.5
                   0.0   0.2          0.4         0.6   0.8   1.0
                                            /a
                                      radius

      additional current drive mechanism (dynamo)
     Hall dynamo is significant
                          j ˜
                          ˜B
             ˜ ˜
      E ||  v  B ||           ||
                                       j   ||
                            ne
                      Hall dynamo
                  (theory        significant)

           Hall dynamo is significant
                                   j ˜
                                   ˜B
                      ˜ ˜
               E ||  v  B ||          ||
                                               j   ||
                                   ne
                               Hall dynamo
 experiment:
 




j ˜
˜B
      ||                                                  Laser Faraday
ne                                                        rotation
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,          QuickTime™ and a
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   plus selected other states




      ~ 6 campus shows
Center Organization
                  Topical Coordinators
             each pair = 1 lab, 1 astro person


• Reconnection                         Yamada, Zweibel
• Momentum transport           Craig, Li
• Dynamo                               Cattaneo, Prager
• Ion Heating                          Fiksel, Schnack
• Chaos and transport          Malyshkin, Terry
• Helicity                             Ji, Kulsrud
• Educational outreach         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)   UCLA
P. Drake            University of Michigan
W. Gekelman         UCLA
R. Lin              UC - Berkeley
G. Navratil         Columbia University
E. Parker           University of Chicago
A. Pouquet          NCAR, Boulder, CO
D. Ryutov           Lawrence Livermore National Lab
CMSO International Liaison Committee

 M. Berger          University College, London, UK
 A. Burkert         The University of Munich, Germany
 K. Kusano          Hiroshima University, Japan
 P. Martin          Consorzio RFX, Padua, Italy
 Y. Ono       Tokyo University, Japan
 M. Velli           Universita di Firenze, Italy
 N. Weiss           Cambridge University, UK
                 CMSO Meetings
Sept, 03        Ion heating/chaos (Chicago)
Sept, 03        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       Dynamo/helicity meeting (Princeton)
June, 05        Intermittency and turbulence (Madison)
June, 05        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       Line-tied reconnection (Los Alamos)
June, 06        Workshop on MSO (Aspen, with CMPD))
Aug, 06 General meeting (Chicago)
                      Budget

• NSF     $2.25M/yr for five years

• DOE     ~$0.4M to PPPL
          ~$0.1M to LLNL
          ~$0.15M to UNH
          all facility and base program support

• LANL    ~$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

								
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