After 1 year of hardwork, I have finally
finished my 200+ pages thesis titled "Dust clusters
in magnetized plasma".
There are many people who have supported me in this thesis who I must
acknowledge, but more on that later. If you would like to share my happiness
in this event, please leave a message here (require hotmail or msn account
to sign in).
This is the abstract of my thesis:
"This thesis is the first detailed experimental
investigations of dust clusters in magnetized rf discharge plasma. Our
experiments performed in a weakly magnetized (up to 100 G) inductive rf
discharge show that dust cluster rotation is dependent on the number of
particles and the magnetic field. Comparson of our experimental results
with current theoretical models demonstrated that dust rotation is largely
due to momentum impact transferred from the partially magnetized ions
in the plasma to the dust particles.
Particles in dust clusters were found to fluctuate predominantly in
the azimuthal direction rather than in the radial direction. A strong
correlation between the packing sequence probability of a cluster
and the particle fluctuation was observed. A magnetic field has been
shown to decrease the amount of particle fluctuations in a dust cluster.
In our experiments, it was found that the radial positions of the dust
particles self-adjusted to accommodate for the change in the ambipolar
electric field. It was also found that dust particles can be confined
by a magnetically-induced electrostatic trap.
Furthermore, our experimental
results demonstrated the possibility in manipulating dust particles with
3 degrees of freedom using a magnetic field as an external, controlled
parameter. The implications of dust rotation due to a magnetic field in
industrial applications, such as the removal of dust contamination in
the manufacture of microelectronics and the fabrication of micro- and
nano- devices in nanotechnology, are discussed."
Here is the "Table
1.1.1. What is dusty plasma?
1.1.2. Examples of dusty plasma
1.1.3. Classification of dust plasma
1.1.4. Dusty plasma research
1.2. Dust dynamics and transport
1.2.1. Innovations from dust dynamics and transport
1.2.2. Dust dynamics in magnetic field
1.3. Current theoretical
models on dust rotation
1.3.1. Konopka’s model
1.3.2. The choice of Coulomb logarithm in ion drag force estimation
1.3.3. Ishihara’s model
1.3.4. Kaw’s model
1.3.5. Shukla's model
1.4. Aim, outlines, and outcomes
of this thesis
2. The experimental apparatus
2.2. The dust particles and the shaker
2.3. The making of dust clusters
2.4. The magnetic coil
2.5. The particle imaging and tracking
3. Structures of dust clusters and crystals
3.1. Planar dust clusters in experiments
3.1.1. Summary of experimental conditions
3.1.2. L-Planar and S-Planar clusters
3.1.3. Cluster radius and radial distance
3.1.4. Metastable states
3.2. Planar dust clusters in computer
3.2.1. Cluster eccentricity and inter-ring
3.2.2. Cluster energy
3.2.3. Our models for computer simulations
3.2.4. Packing sequences
3.2.5. Inter-ring twist spectrum
3.2.6. Energy and inter-ring twist relation
3.2.7. Influence of cluster eccentricity on inter-ring twist
3.3. Other types of dust clustes and
3.3.1. Summary of experimental conditions
3.3.2. Particles strings and three-dimensional
3.3.3. Large crystals and annular crystals
3.4. Magnetically induced
confinement of dust particles
3.4.1. Confinement electric field
3.4.2. The effect of axial magnetic field on
confinement electric field
3.4.3. Intermediate clusters and magnetic confinement of dust
3.4.4. Superposition of electrostatic
potentials and translational force
4. Rotation of dust clusters
4.1. Planar cluster
4.1.1. Properties of the planar cluster rotation
4.1.2. Angular velocity
4.1.3. Angular velocity saturation
4.1.4. Angular momentum
4.1.5. Threshold magnetic field
4.1.6. Phase diagram and periodic pause
4.1.7. Translational force
4.1.8. Cylindrical assymmetry in confinement potential
4.2. Rotation of other types of dust
clusters and crystals
4.2.1. Rotation of intermediate clusters
4.2.2. Rotation of particle strings and three dimensional clusters
4.2.3. Rotation of large crystals and annular crystals
4.3. Comparison of experimental results
with current theroies
4.3.1. With reference to konopka's model
4.3.2. With reference to Ishihara's model
4.3.3. With reference to Kaw's model
4.3.4. With reference to Shukla's model
4.4. Further remarks on dust
4.4.1. Neutral gas flow
4.4.2. Dust charge gradient
4.4.3. Divergence of magnetic field
5. Fluctuations of planar dust
5.1. Cluster instabilities
5.1.1. Radial instability
5.1.2. Azimuthal instability
5.1.3. Total instability and instability
5.2. Cluster instabilities versus number
5.2.1. Radial instabilites versus number
5.2.2. Azimuthal instability coefficient versus number
5.2.3. Dominance of azimuthal component in cluster
5.2.4. Total instability coeffiecient versus number
instabilites and magnetic field
5.3.1. Radial and azimuthal instabilities
versus magnetic field
5.3.2. Total instability coefficient versus magnetic field
Further remarks on dust fluctuations
6. Future applications
6.1. Dust removal
6.2. Plasma diagnostics
6.3. Magnetic manipulation device
6.4. Thin film coating with magnetron sputtering
6.5. Particle assisted ion etching
is some of the behind the scene photos of the thesis construction process
over the last few days.
We used HP premium choice laser paper for the thesis.
They are the highest quality acid-free, uncoated paper with maximum smoothness
and brightness for the high quality graphics in the thesis.
Here is a test we did on the comparison of the quality of the paper.
Printing thesis on our color laserjet.
After binding, this is my 200+ pages thesis.
And the graphics are just superb.
Lastly, I am deeply grateful to a group
of people without which the completion of this thesis would not be possible.
In particular, I would like to highlight three very important people.
Firstly, I would like to thank my co-supervisor, Dr. Alex Samarian, for
the vast amount of knowledge he taught me not only in Physics, but also
in life. His innovative ideas led the project into a new direction. More
importantly, his encouragement to express my visualization skills and
artistic ideas during my scientific research had resulted in many illustrations
and concepts seen throughout this thesis. Secondly, I would like to thank
my former colleague, Dr. Nathan Prior, for his help in building my experimental
apparatus and the mechanical skills he passed onto me. His unconditional
contribution is a key element in the success of this project. Thirdly,
I would like to thank my supervisor, Prof. Brian James, for his leadership
in this project and his help in my transfer of PhD to the University of
Sydney. His comments and suggestions are part of what constructed the
final form of this thesis.
Thanks must go to three talented students: Cameron Ford and Stephen
Barkby with their help in developing the computer routines in the
simulation of planar cluster systems; and Christopher Brunner for
his help in the analysis of cluster instabilities.
Thanks must go to the University
of Sydney. This includes Dr. Nicole Bordes and the Sydney Regional Scientific
Visualization Laboratory for their help in scientific visualization.
Thanks must go to the Flinders University
of South Australia. This includes my former supervisor, Dr. Leon Mitchell,
for his introduction into the field of dusty plasma; the technicians from
the electrical and mechanical workshop, Bob Northeast, Mike Mellow, Peter
Mariner at the School of Physics for the construction of the experimental
apparatus; Dr. Michelle Hale and the School of Biological Sciences
for the use of the image acquisition system; and Ms. Katie Green
and the School of Chemistry for the use of the copper vapor deposition
Thanks must go to the Australian Research
Council for their financial support of this project over the last three
and a half years.
Thanks must go to the State Key Laboratory
of Materials Modifications by Beams at the Dalian University of Technology.
This includes Jayson Ke Jiang for contacting me through our research website
and thus initiated our collaborative researches and Lu-Jing Hou for repeating
his computer simulations specifically for my experimental conditions.
Lastly, I would like to thank my family
for their unconditional support both financially and emotionally in the
last 25 years. Without their faith in me, I could not have endured this
one year of painstaking thesis writing. In particular, I am in great debts
to my beloved mother and grandmother as I will never be able to compensate
the number of fine lines that have appeared on their faces over this
period of time.