

Title of Thesis
Quantum Effects on Low Frequency Waves in Dense Plasmas 
Author(s)
Shabbir Ahmad
Khan 
Institute/University/Department
Details Department of Physics / COMSATS Institute of
Information Technology, Islamabad 
Session 2010 
Subject Physics 
Number of Pages 115 
Keywords (Extracted from title, table of contents and
abstract of thesis) Dense, quantum, plasmas, low,
frequency, waves, effects, solutions 
Abstract using the quantum
hydrodynamic formulation. Several linear and nonlinear waves in
uniform as well as nonuniform plasmas are investigated taking into
account the quantum diffraction and quantum statistical effects. In
an inhomogenous plasma, the drift type wave can appear which doesn’t
require electron temperature to be non‐zero for its existence and
the electron quantum effects contribute to the wave dispersion at
very short length scales. The effect of stationary dust is also
discussed. It is also found that the drift wave of ultracold dense
plasma can couple with Alfven wave and the linear dispersion
relation is analogous to the classical plasma case. But physically,
both the dispersion relations are very different. The dispersion
relations are analyzed numerically for particular cases of ultracold
dense plasma. In a homogenous quantum plasmas, the linear waves are
studied for electron‐ion as well as stationary dust case. It is
found that the quantum ion‐acoustic wave frequency in the presence
of background dust increases with electron quantum effects and dust
concentration. In a magnetized electron‐ion plasma, the wave
frequency increases with electron number density and magnetic field.
The linearly coupled electrostatic and Alfven waves are also
investigated and the role of electron fermionic pressure in the wave
dynamics of dense quantum plasmas is pointed out. A comparison of
fermionic pressure with the quantum pressure due to Bohm potential
term is presented. The limit of ultracold dense plasma is discussed
in the light of this comparison. The wave dispersion properties for
static as well as dynamic ions are elaborated. In the nonlinear
regime, it is found that the dust concentration in unmagnetized
plasma increases the amplitude and width of dust ion‐acoustic
soliton whereas the increase in quantum diffraction parameter
reduces the width of the soliton, but doesn’t affect its amplitude.
For, magnetized electron‐ion quantum plasma, the quantum diffraction
effects are found to increase the amplitude as well as width of the
solitons. The increase in magnetic field shrinks the soliton keeping
the amplitude constant. The results presented in this thesis are
supported by numerical analysis and illustrations. The relevance of
the study with dense astrophysical and laboratory Plasmas is also
pointed out.

