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Overview of CMSO Center for Magnetic Self-Organization in Laboratory and Astrophysical Plasmas S. Prager May, 2006.

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Presentation on theme: "Overview of CMSO Center for Magnetic Self-Organization in Laboratory and Astrophysical Plasmas S. Prager May, 2006."— Presentation transcript:

1 Overview of CMSO Center for Magnetic Self-Organization in Laboratory and Astrophysical Plasmas S. Prager May, 2006

2 Outline Physics topics Participants Physics goals and highlights Educational outreach Management structure Funding

3 Magnetic self-organization

4 The nonlinear plasma physics

5 Magnetic self-organization in the lab toroidal magnetic flux heat flux (MW/m 2 ) rotation (km/s) ion temperature (keV) dynamo magnetic fluctuations energy transport momentum transport ion heating time (ms) (reconnection)

6 CMSO goal: understand plasma physics needed to solve key laboratory and astrophysical problems linking laboratory and astrophysical scientists linking experiment, theory, computation

7 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

8 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

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

10 yields range of topologies and critical parameters Joint experiments and shared diagnostics Experimental facilities

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

12 SSX Electrostatically - produced spheromaks (by plasma guns) Two spheromaks reconnect and merge MRX Inductively produced plasmas, Spheromak or annular plasmas Locailzed reconnection at merger

13 MST Reversed field pinch SSPX Electrostatically - produced spheromak

14 Liquid gallium MRI experiment (Princeton) To study the magnetorotational instability

15 Major Computational Tools Not an exhaustive list Codes built largely outside of CMSO Complemented by equal amount of analytic theory

16 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)

17 Reconnection Two-fluid Hall effects Reconnection with line tying Effects of coupled reconnection sites Effects of lower hybrid turbulence not foreseen in proposal

18 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

19 Observation of Hall effects MRX SSX radius also observed in magnetosphere Observed quadrupole B component,

20 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)

21 Linear theory for mode resonance in cylinder radius v periodic line-tied

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

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

24 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)

25 Lower hybrid turbulence Detected in MRX Reconnection rate turbulence amplitude; Instability theory developed, May explain anomalous resistivity Magnetic fluctuations 0 10 f(MHz)

26 Lower hybrid turbulence Detected in MRX Reconnection rate ~ turbulence amplitude; Instability theory developed, May explain anomalous resistivity Similar to turbulence in magnetosphere (Cluster) E B Magnetic fluctuations 0 10 f(MHz)

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

28 Leading explanation in lab plasma resistive MHD instability current-driven (tearing instability) momentum transported by j x b and v. v Leading explanation in astrophysics MHD instability Flow-driven (magnetorotational instability) momentum transported by j x b and v. v

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

30 MRI in Gallium Experiment (Princeton) hydrodynamically stable, ready for gallium v r --- Couette flow + diff. endcaps + end caps rotate with outer cyl. Simulation (Chicago) underway V experiment radius Couette flow

31 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

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

33 Theory and computation of Maxwell stress in MHD r resonant surface quasilinear theory for one tearing mode 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)

34 Ion Heating

35 Ion heating in solar wind r/R sun Strong perpendicular heating of high mass ions thermal speed km/s

36 Ion heating in lab plasma MST Observed during reconnection in all CMSO experiments t = ms t = ms T i (eV) radius

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

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

39 Magnetic energy can be converted to Alfvenic jets magnetic energy Energetic ion flux time ( s) SSX

40 Ions heated only with core and edge reconnection T i (eV) time (ms) core reconnection edge reconnection MST coreedge

41 What is mechanism for ion heating? Still a puzzle Theory of viscous damping of magnetic fluctuations has been developed

42 Magnetic chaos and transport Magnetic turbulence Transport in chaotic magnetic field

43 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

44 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 Measurements underway in experiment for comparison computation

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

46 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

47 The Dynamo

48 Why is the universe magnetized? Growth of magnetic field from a seed Sustainment of magnetic field Redistribution of magnetic field

49 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

50 The disk-jet system Field sustained (the engine) Field produced from transport

51 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

52 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.

53 MHD computation of Jet production |J| contours Magnetically formed jet

54 MHD computation of Jet evolution |J| contours Magnetically formed jet When kink unstable, flux conversion B -> B z Similarities to experimental fields helical fields develop in jet

55 in experiment E || j || radius additional current drive mechanism (dynamo) Dynamo Effect in the Lab

56 Hall dynamo is significant Hall dynamo (theory significant)

57 Hall dynamo is significant Laser Faraday rotation Hall dynamo experiment:

58 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) Questions for the lab plasma, relevant to astrophysics

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

60 ~ 6 campus shows ~ 150 traveling shows/yr all 72 Wisconsin counties, plus selected other states

61 Center Organization

62 Topical Coordinators ReconnectionYamada, Zweibel Momentum transportCraig, Li DynamoCattaneo, Prager Ion HeatingFiksel, Schnack Chaos and transportMalyshkin, Terry HelicityJi, Kulsrud Educational outreachReardon, Sprott each pair = 1 lab, 1 astro person

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

64 S. Cowley (Chair)UCLA P. DrakeUniversity of Michigan W. GekelmanUCLA R. LinUC - Berkeley G. NavratilColumbia University E. ParkerUniversity of Chicago A. PouquetNCAR, Boulder, CO D. RyutovLawrence Livermore National Lab CMSO Program Advisory Committee

65 CMSO International Liaison Committee M. BergerUniversity College, London, UK A. BurkertThe University of Munich, Germany K. KusanoHiroshima University, Japan P. MartinConsorzio RFX, Padua, Italy Y. OnoTokyo University, Japan M. VelliUniversita di Firenze, Italy N. WeissCambridge University, UK

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

67 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

68 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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