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|Title: ||Quantum corrections for fundamental plasma behaviors|
|Other Titles: ||Deng li zi ti ji ben xing wei de liang zi xiu zheng|
|Authors: ||Wu, Zhengwei (吳征威)|
|Department: ||Department of Physics and Materials Science|
|Degree: ||Doctor of Philosophy|
|Issue Date: ||2010|
|Publisher: ||City University of Hong Kong|
|Subjects: ||Plasma dynamics.|
|Notes: ||CityU Call Number: QC718.5.D9 W8 2010|
iv, vii, 90 leaves : ill. 30 cm.
Thesis (Ph.D.)--City University of Hong Kong, 2010.
Includes bibliographical references (leaves 79-86)
|Abstract: ||Quantum plasmas have received considerable attention in recent years. The
quantum effects become important if the typical distance separating particles in a
plasma system becomes comparable or less than the de Broglie wavelength of the
particles. This condition will be satisfied when the Fermi temperature is greater than
thermal temperature of plasmas; thus quantum effects become important. The electrons
in the plasmas approach to a Fermi gas, their statistical behavior is described
by Fermi-Dirac distribution instead of classical Boltzman distribution.
Quantum hydrodynamics (QHD) is the most widely used hydrodynamic model,
which deals with transport processes of particles, the momentum of particle and
macroscopic physical quantities like energy. Together with the status equation,
they form a complete set of equations to describe quantum plasmas from the fluid
dynamics’ point of view. Besides, Quantum Magnetohydrodynamic (QMHD) model
is established based on QHD equations and takes into account of magnetic field.
This research is based on QMHD model to investigate the different waves and fluid
instabilities in magnetized plasmas.
This thesis includes some parts as described in the following. First, based on the
quantum hydrodynamic equations with magnetic field, we investigated the dispersion
relation of some types of linear waves in quantum magnetized plasmas. Our
results indicate that the quantum corrections have significant effects on the dispersion
properties of the Langmuir wave.
Second, we studied the general dispersion equation for quantum magnetized
warm plasmas. Using the plasma dielectric tensor, we obtained the dispersion relations
of magnetoelectric waves and multi-stream instability by solving the dispersion
equation. The parallel magnetic field has no effects on stream instability, while twostream
instability is altered remarkably by quantum effects and thermal effects.
Third, the electromagnetic drift waves of nonuniform quantum magnetized EPI
plasmas on the basis of the QMHD model were discussed by taking the thermal and
Fermi pressure terms into account. We found that the drift wave is unstable when
the wave vector has a component along the axis and the growth rate is approximately
proportional to the square of the electron number density gradient.
Fourth, the electrostatic drift waves (EDWs) in nonuniform quantum pair plasmas
placed in an external magnetic field were investigated. We derived the analytic expression of the dispersion relation of EDWs with the presence of equilibrium magnetic
field inhomogeneity and show that a new, purely quantum, branch appears.
This new electrostatic drift mode does not exist in classical pair plasmas and has
no vital relation with quantum statistic effects.
Next, the Rayleigh-Taylor (RT) instability in an ideal incompressible quantum
magnetized plasma system was researched. Using the exponential density distribution
and fixed boundary conditions, we derive the analytical expression of the growth
rate of RT instability. The RT instability is affected significantly by quantum effects.
Quantum mechanical effects suppress the RT instability in proper circumstances.
Moreover, we calculated the electrostatic drift waves (EDW) in nonuniform threedimensional
Fermi plasma placed in an external magnetic field. The dispersion relation
of EDWis obtained. The new quantum diamagnetic drift velocity and quantum
ion-acoustic velocity are introduced and shown to be much greater than their respective
value under classical circumstances. The dispersion relation is affected and
altered obviously by quantum mechanical effects.
At the last, we consider the possible electrostatic drift waves (EDWs) in quantum
dusty plasmas. The dust self-gravitational effects are taken into account. One
can see that the Jeans terms induced by the dust gravitation perturbation exert
significant effects on the dispersion relation. Under these environment, a drift-like
instability is induced by the Jeans terms.|
|Online Catalog Link: ||http://lib.cityu.edu.hk/record=b3947662|
|Appears in Collections:||AP - Doctor of Philosophy |
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