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Ion Diffusion and Convection in Quiet and Turbulent Plasmas

Broad Participation over Many Years. . . Irvine Boehmer, Bowles, Edrich, Heidbrink, Hill, Koslover, Okubo, Rynn, Sheehan, Wolf, Zhang, Zhao, Zhou, Zimmerman, ZintlLausanne Furno, PlyushchevCulham, Imperial College Sharapov, LilleyAustin BreizmanLos Angeles Carter, Gekelman, Leneman, Tripat

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Ion Diffusion and Convection in Quiet and Turbulent Plasmas

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    1. Ion Diffusion and Convection in Quiet and Turbulent Plasmas June 2010

    2. June 2010

    3. Abstract June 2010

    4. We seek to understand transport in space and velocity-space June 2010

    5. We divide the ion world in two parts June 2010

    6. June 2010 Ion Transport is measured by creating and following test-ions

    7. June 2010 Spatial diffusion can be seen by the diffusive spreading of the test-ion population with time

    8. June 2010 Spatial convection is seen by movement of the center of the test-ion population.

    9. June 2010 Quiet plasma: diffusion of slow ions is classical, Coulomb (plus a small turbulent contribution

    10. June 2010

    11. June 2010

    12. Quiet plasma: diffusion of fast ions is classical, Coulomb June 2010

    13. June 2010 The world is not always Maxwellian

    14. June 2010 Velocity-space transport can be observed by following test-ions in phase-space over time.

    15. June 2010 Slow ion velocity transport studied via laser tagging

    16. June 2010 Slow ion velocity-space transport coefficients

    17. 17 June 2010

    18. Measured the Doppler shifted fast-ion cyclotron resonance with shear Alfvén waves Shear Alfvén waves launched by various antennas Measure beam spreading vs. frequency, amplitude, and polarization Excellent quantitative agreement with theory

    19. DoneDone

    20. DoneDone

    21. Fast Ion Alfvén Resonance Setup Fast ions complete 3 gyro-periods before collection at Collimated Energy Analyzer z position ~600 eV Li+ beam initial pitch angle at 49.3o relative to B field Energy Analyzer incident angle matches the initial pitch angle single loop antenna & dual polarization antenna are used to launch linear/circular polarized Shear Alfvén waves (SAW) Li+ beam orbit overlaps partially/fully with SAW for wave-particle interaction DoneDone

    22. Doppler Shifted Cyclotron Resonance is easier to achieve than Landau Resonance Done Done

    23. Single Particle Model is First Used for Experiment Design DoneDone

    24. Wave Fields Model DoneDone

    25. Wave Modulates Fast-ion Energy and Magnetic Moment Under Resonant Condition DoneDone

    26. MC Simulation Results: SAW Induced Spatial Shifting at Resonance Frequency Change with new picturesChange with new pictures

    27. MC Simulation Results: SAW Mainly Causes Drifting at Non-resonance Frequency Why G.C.DriftWhy G.C.Drift

    28. MC Simulation Results: Fast Ion Beam Profile Widens Substantially at Resonance Frequency DoneDone

    29. Various Fast Ion Sources developed by UC Irvine Fast-Ion Group Add outline pageAdd outline page

    30. Collimated Energy Analyzer measures SAW-modulated Fast Ion Signal Fast Ion Analyzer rotated to match pitch angle of incoming beam Fast Ion Analyzer records resonant beam signal in addition to DC signal Proper shielding and isolation is important to cut down noise level New probe design?New probe design?

    31. Plasma Parameter and Fast Ion Beam Profile Measurement at LAPD DoneDone

    32. Alfvén Wave Spatial Pattern Is Chosen to Accelerate and Decelerate Fast Ions

    33. Antenna and SAW Spatial Pattern Are Chosen to Accelerate and Decelerate Fast Ions Need Pic FromTroyNeed Pic FromTroy

    34. Measured Wave Magnetic Field Is Used to Model the Resonance Interaction

    35. Beam Spot Widened by Left-Handed Polarized Shear Alfven Wave With Moderate Amplitude DoneDone

    36. Beam Spot Remains Same at Right-Handed Polarized Shear Alfven Wave With Same Frequency and Amplitude DoneDone

    37. Wave Amplitude Study Shows Beam Spot Spread More With Higher Wave Amplitude DoneDone

    38. Monte-Carlo Simulation Result Agree With Experimental Data In Both Left-Handed and Right-Handed Case Or Use the Color Filled Contour?Or Use the Color Filled Contour?

    39. Monte-Carlo Simulation Result Agree With Experimental Data In Both Left-Handed and Right-Handed Case

    40. SAW Frequency Scan Shows Beam Radial Profile Broadening Reach Maximum at Resonance Frequency DoneDone

    41. Quantitatively Estimate Displacement: ?r is Modeled by “Wobbling” Unperturbed Beam Profile

    42. Beam Spot Displacement at Various Frequency Agrees with Resonance Theory Inferred displacement, define trianglesInferred displacement, define triangles

    43. Triangle Wave Cause Inaccuracy at Harmonic Frequency Comparing With Sinusoidal Wave

    44. Experimental Setup for Turbulence Wave Interaction with Fast Ion Fast ions complete several gyro-periods before collection at Collimated Fast Ion Analyzer z position ~400 to 1000eV Li+ beams with different initial pitch angles and gyro-radius are launched Fast Ion Analyzer incident angle matches the initial pitch angle Compressed field/Plate launch turbulence wave with circular/linear geometry Li+ beam orbit overlaps partially with turbulence wave region for wave-particle interaction

    45. Size of collector compare to spot size, what is pitch angle?Size of collector compare to spot size, what is pitch angle?

    48. Measure beam spot just behind obstacle at various distances from the source

    49. 17 June 2010

    52. 17 June 2010

    64. 17 June 2010

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