radiation pressure and gas drag forces on a single particle and wave excitation in a dusty plasma n.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
Radiation pressure and gas drag forces on a single particle and wave excitation in a dusty plasma PowerPoint Presentation
Download Presentation
Radiation pressure and gas drag forces on a single particle and wave excitation in a dusty plasma

Loading in 2 Seconds...

play fullscreen
1 / 32

Radiation pressure and gas drag forces on a single particle and wave excitation in a dusty plasma - PowerPoint PPT Presentation


  • 136 Views
  • Uploaded on

Radiation pressure and gas drag forces on a single particle and wave excitation in a dusty plasma. B. Liu, J. Goree, V. Nosenko, K. Avinash. plasma = electrons + ions. small particle of solid matter. absorbs electrons and ions. becomes negatively charged. Debye shielding.

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

Radiation pressure and gas drag forces on a single particle and wave excitation in a dusty plasma


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
    Presentation Transcript
    1. Radiation pressure and gas drag forces on a single particle and wave excitation in a dusty plasma B. Liu, J. Goree, V. Nosenko, K. Avinash

    2. plasma = electrons + ions small particle of solid matter • absorbs electrons and ions • becomes negatively charged • Debye shielding What is a dusty plasma? & neutral gas

    3. Forces Acting on a Particle Coulomb QE Gravity mg • Other forces: • Gas drag • Ion drag • Thermophoresis • Radiation Pressure

    4. polymer microspheres 8 mm diameter Particles • separation a» 0.5 mm • charge Q» - 104e

    5. Confinement of 2D monolayer • Interparticle interaction is repulsive Coulomb (Yukawa) • External confinement by curved electric sheath above lower electrode

    6. triangular lattice with hexagonal symmetry 2D lattice Yukawa inter-particle potential

    7. momentum imparted to microsphere Radiation Pressure Force incident laser intensity I transparent microsphere Force =0.97I rp2

    8. Setup Argon laser pushes particles in the monolayer

    9. Chopping chopped beam beam dump scanning mirror chops the beam Ar laser mirror

    10. laser beam • Accelerated by laser radiation pressure • Restored by confining potential Coulomb radiation pressure drag • Damped by gas drag Single-particle laser acceleration

    11. 2 mm Ar laser sheet Movie of particle accelerated by laser beam

    12. Equation of motion • Assumption: • The dominant forces are • Gravity • Vertical sheath electric field • Radiation pressure force • Drag force • Horizontal confining potential • One dimensional motion

    13. record particle’s orbit R R Gas drag coefficient R is an adjustable parameter to minimize the discrepancy between and . Calculation: radiation pressure, gas drag, confining potential

    14. Horizontal confining potential energy

    15. Radiationpressureforce

    16. Gas drag force

    17. Coefficients for radiation pressure and gas drag Radiation pressure q result: measurment0.94  0.11 ray optic theory0.97 Gas drag result: measurment1.26  0.13 Epstein theory 1 ~ 1.44 Epstein, Phys. Rev. 1924

    18. Laser sheet Application of radiation pressure force

    19. Q=0,  / 0 Dispersion relationsin 2D triangular lattice Wang et al. PRL 2001

    20. laser beam y x z Waves in one-dimensional dusty plasma chain • Longitudinal (along the chain) : acoustic • Transverse (perpendicular to the chain) : optical • The oscillation in • y direction ( horizontal confining potential) • z direction ( potential well formed by gravity and sheath )

    21. optical acoustic Optical mode in solid(two atom in primitive cell)

    22. Optical mode in one-dimensional chain • Assumptions: • One dimension, infinite in x direction • Parabolic confinement in y direction • Yukuwa interaction potential • Nearest neighbor interaction • No gas damping Optical: Acoustic:

    23. “Optical” branch Acoustic branch Dispersionrelation

    24. 22-particle chain Ashtray electrode z y x Formation of one-dimensional chain

    25. y x Bifurcation of chain • Potential gradient in x direction • Minimum potential energy requirement • Particle-particle interaction energy • Confining potential energy

    26. 1 2 Case 1 No bifurcation condition Case 2 Ux Uy x y Bifurcation condition

    27. Resonance frequency:x x = 0.07 Hz Single-particle laser acceleration

    28. Resonance frequency:y laser-excited resonance vibration laser sheet

    29. Resonance frequency:y Velocity autocorrelation function of random motion

    30. Excitation of optical mode Laser beam

    31. Excitation of optical mode Laser beam

    32. dusty.physics.uiowa.edu