Dusty Plasma and Plasma Torches

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Dusty Plasma and Plasma Torches Powered By Docstoc
					Dusty Plasma
 and Plasma
  Torches
    Fred Pacifico
  Rebecca Shipman
                    http://alexandria.tue.nl/extra3/proefschrift/boeken/9902693.pdf
             Objectives
 Questions
 NRL DUPLEX
     Specifications
     Schematic
   Dust Cloud Structure
   The PIV process
   Particle Flow Path
   Micro-particle Transport
              Objectives
 Open Air Plasma Generator
 Electrode Configuration for Waste Melting
 Nozzle Length
 Cathode Erosion
 Plasma Catalysts and their Generation
 Answers to the Questions
 Conclusions
              Questions

1. What is PIV and explain the
   process?

2. List the four steps involved in the
   plasma catalyst generation process.
                                     NRL DUPLEX

                                                           NRL – Naval
                                                           Research Lab

                                                           DUPLEX – DUsty
                                                           PLasma EXperiment


The NRL DUPLEX device with argon dc
glow discharge plasma.
      http://www.nrl.navy.mil/content.php?P=03REVIEW143
     DUPLEX Specifications
 0.5-in.thick optically transparent
 polycarbonate cylinder
   Provides a 360° view of experimental
    region
 80 cm (diameter) X 80 cm (height)
 Argon dc glow discharge plasmas
 Grounded, 75 cm diameter cathode
               http://www.nrl.navy.mil/content.php?P=03REVIEW143
     DUPLEX Specifications
 Biased, 10 cm diameter anode
   300-1000 V range
 Cathode and anode separation:
   Maximum of 75 cm
   Typically 15-20 cm
 Pressure range of 50-300 mTorr
 Alumina micro-particles have an average
 diameter of <d> ~ 1.2 +/- 0.5 μm
               http://www.nrl.navy.mil/content.php?P=03REVIEW143
  DUPLEX Schematic




Schematic drawing of the DUPLEX experiment.

         http://narn.physics.auburn.edu/etjr/papers/thomas_DUPLEX2.pdf
                    Dust Cloud Structure
                                                        250 mTorr, 1000 V bias
                                                        Horizontal extent ~ 5 cm
                                                        Vertical extent ~ 3 cm
                                                        Banding is not
                                                         reflections or shadows
                                                          Regions with low or no
                                                           particles present
                                                      Particles are believed to
Structured dust cloud of 1-                              be generally constrained
µm alumina particles above
the cathode in DUPLEX.                                   to their specific bands
 http://www.nrl.navy.mil/content.php?P=03REVIEW143
 Particle Image Velocimetry (PIV)
 Pioneered by Dr. Edward Thomas, Jr. and
  the “dusty plasma group” at AUBURN
 Illuminate suspended micro-particles using
  a pair of 30 ns laser pulses that are
  expanded by cylindrical lenses into light
  sheets, separated in time.
 The laser pulses are synchronized to the
  frame grabbing rate of a CCD camera,
  ensuring that each pulse appears on a
  single video frame
               http://www.nrl.navy.mil/content.php?P=03REVIEW143
 Particle Image Velocimetry (PIV)
 The displacement of the particles can then
 be calculated by viewing their relative
 positions in the subsequent video frames.

 From their displacement and the known
 time interval, two-dimensional velocity
 vectors can be computed in the plane of
 illumination.

               http://www.nrl.navy.mil/content.php?P=03REVIEW143
Particle Image Velocimetry (PIV)

                                                      PIV measurement
                                                      of the charged
                                                      micro-particle
                                                      velocities in the
                                                      dust cloud shown
                                                      in the previous
                                                      figure.
 http://www.nrl.navy.mil/content.php?P=03REVIEW143
  Why is Dusty Plasma More Appealing to
   Work With Than Electrons and Ions?
                                                                          “One of the most appealing
                                                                          aspects of dusty plasma research
                                                                          is that because of the relatively
                                                                          large size of the dust grains (as
                                                                          compared to the ions and
                                                                          electrons in the plasma), many of
                                                                          the phenomena in dusty plasma
                                                                          are both macroscopic (visible to
                                                                          the naked eye) AND have slow
                                                                          time evolution (~ up to several
                                                                          tens of seconds) which allows
A color image of two separated dust                                       many dusty plasma phenomena
clouds in DUPLEX
                                                                          to be directly imaged.” - Dr. E.
                                                                          Thomas, Jr.
   http://www.physics.auburn.edu/~plasma/basic/dusty/dusty_gallery.html
                            Particle Flow Path
                                                                Arrangement of the dust sources on
                                                                the cathode in the DUPLEX
                                                                experiment. Particles flow from the
                                                                outer cloud, labeled point A to the
                                                                intermediary locations, labeled
                                                                points B and B'. The particles flow
                                                                to either B or B', but not to both
                                                                points at the same time. The
                                                                particles then flow from the
                                                                intermediary point to the large
http://narn.physics.auburn.edu/etjr/papers/thomas_DUPLEX2.pdf
                                                                cloud at the center of the chamber,
                                                                labeled C.
Particle Transport in DUPLEX
                                                                 The points are labeled using
                                                                 the same scheme as in the
                                                                 previous figure.
                                                                 The dust sources are seen on
                                                                 the surface of the cathode.
                                                                 The arrows indicate the flow
                                                                 direction of the micro-particles
                                                                 in the plasma.
                                                                 The large dashed line indicates
                                                                 the location of the boundary of
                                                                 the cathode.
 http://narn.physics.auburn.edu/etjr/papers/thomas_DUPLEX2.pdf   The bottom of the anode can
                                                                 also been seen.
         Evolution of the Micro-particle
                   Transport




Initial series of still images showing the temporal evolution of the micro-particle transport.
                               http://narn.physics.auburn.edu/etjr/papers/thomas_DUPLEX2.pdf
         Evolution of the Micro-particle
                   Transport




Mid-series of still images showing the temporal evolution of the micro-particle transport.
                              http://narn.physics.auburn.edu/etjr/papers/thomas_DUPLEX2.pdf
          Evolution of the Micro-particle
                    Transport




Final series of still images showing the temporal evolution of the micro-particle transport.
                              http://narn.physics.auburn.edu/etjr/papers/thomas_DUPLEX2.pdf
                     Open Air Plasma Generator
          Cold Plasma
           Generator
          RF Field
          Stable and
           Homogeneous
           Plasma
          Increasable Area

M. Koide, T. Horiuchi, T. Inushima, B.J. Lee, M. Tobayama, H. Koinuma, “A novel low temperature plasma generator with alumina coated electrode for open air material processing,” Thin Solid Films
                                                                                      316, 1998, pp. 65-67.
              Electrode Configuration for Waste
                          Melting
               Nozzle-type
                      Electrode Length
                          Constriction of arc
                          Different arc
                           voltages
                          Power transferred
                           to the anode
                          Heat losses

] M, Hur, T. H. Hwang, W. T Ju, C. M. Lee, S. H. Hong, “Numerical analysis and experiments on transferred plasma torches for finding appropriate operating conditions and electrode configuration for
                                                                     a waste melting process,” Thin Solid Films 390, 2001, pp.
                                                           Nozzle Length




] M, Hur, T. H. Hwang, W. T Ju, C. M. Lee, S. H. Hong, “Numerical analysis and experiments on transferred plasma torches for finding appropriate operating conditions and electrode configuration for
                                                                     a waste melting process,” Thin Solid Films 390, 2001, pp.
                 Cathode Erosion

 Ion Implantation
   Vacuum conditions
   Substrate Mask
   Variations in:
      arc velocities
      arc voltage
      cathode erosion



         I.R. Jankov, I.D. Goldman, R.N. Szente, “Ion implantation for plasma torches,” Vacuum 65, 2002, pp. 548-553
         Plasma Generated Catalysts
 Carbon
          High melting point
          High surface area
          High dispersion catalysts
 Low Pressure Plasma
 Working Gas of Argon


H. Zea, C.K. Chen, K. Lester, A. Phillips, A. Datye, I. Fonseca, J. Phillips, “Plasma torch generation of carbon supported metal catalysts,” Catalysis Today 89, 2004, pp. 237-244
                              Catalysts Generation
 Four Steps
          Precursors nitrate
           decomposes
          The metal atoms released
           by the decomposition
           absorb on the carbon
           particles
          High velocity diffusion of
           atoms on the carbon
           surface leads to particle
           formation.                                                                                     PdAg/C catalyst, which show
                                                                                                          particles of an ordinary shape as
          High velocity diffusion and                                                                    well as some with a complex
           particle growth ceases                                                                         ‘snake’ shape.

H. Zea, C.K. Chen, K. Lester, A. Phillips, A. Datye, I. Fonseca, J. Phillips, “Plasma torch generation of carbon supported metal catalysts,” Catalysis Today 89, 2004, pp. 237-244
                 Answer #1
 PIV is particle image velocimetry.
 Illuminate suspended micro-particles using a
  pair of 30 ns laser pulses that are expanded by
  cylindrical lenses onto light sheets, separated in
  time.
 The laser pulses are synchronized to the frame
  grabbing rate of a CCD camera, ensuring that
  each pulse appears on a single video frame
 The displacement of the particles can then be
  calculated by viewing their relative positions in
  the subsequent video frames.
 From their displacement and the known time
  interval, 2-D velocity vectors can be computed.
                Answer #2
 Four Steps to Catalyst Generation
   Precursors nitrate decomposes
   The metal atoms released by the
    decomposition absorb on the carbon particles
   High velocity diffusion of atoms on the carbon
    surface leads to particle formation.
   High velocity diffusion and particle growth
    ceases
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