Department of Physics
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Item Study of Streaming Dust Acoustic Instability in Quantum Plasma(Library Information Services, COMSATS University Islamabad, Lahore Campus, 2018) Asif Zahoor; FA16-RPH-031; Dr. Muhammad Jamil; LHR TP 5240In this thesis a study related to Streaming Dust Acoustic Instability in Quantum Plasma is done. In this investigation starting from equation of motion containing Fermi Pressure, Bohm Potential and Exchange Correlation term we use quantum hydrodynamic (QHD) model to derive a general expression for dielectric constant which led to the final dispersion relation. A graphical discussion is also made by considering real part which shows the phase speed of DAWs whereas the imaginary part give the growth rate. The graphical results are obtained by varying the mass of dust particles, number density of electrons and by taking different streaming speed. This research is expecting a great scope in astrophysical quantum plasmasItem Study of Dust Acoustic Waves with Dust Charge Fluctuation in Quantum Plasm(Library Information Services, COMSATS University Islamabad, Lahore Campus, 2018) Rubina; FA16-RPH-016; Dr. Muhammad Jamil; LHR TP 5230In this dissertation, the time-dependent charge fluctuation of dust particles have been studied in quantum dusty plasmas. The dust acoustic wave has been taken as the perturbation of the plasma system. The quantum fluid model consisting upon momentum balance equation, continuity equation and gravitational Poisson’s equation has been employed to solve for the dispersion relation. The instability of the wave in the form of damping is observed. It is noticed that the dust acoustic wave went to damp for the whole spectrum of k on varying ion-thermal temperature, electron number density and dust radii.Item Electromagnetic Polarization in Ionized Quantum Plasmas(Library Information Services, COMSATS University Islamabad, Lahore Campus, 2024) Muhammad Bilal Rafiq; CIIT/FA22-RPH-011/LHR; Dr. Muhammad Jamil; LHR TP 9429This study investigates the influence of ionization dynamics on polarized electromag netic modes in quantum plasmas, an area crucial for various applications from astro physics to nanotechnology. By employing a Quantum Hydrodynamic Model (QHD) and numerical simulations with Mathematica, we aim to understand how ionization affects the polarization characteristics of electromagnetic waves. Despite its signifi cance, there’s a lack of comprehensive research on this topic. The QHD model, inte grating quantum effects like Bohm potential and Fermi pressure, provides a mathemat ical framework to analyze the behavior of these modes at the quantum scale. Through analytical and numerical approaches, we aim to interpret the interplaybetween plasma ionization and polarization, shedding light on fundamental aspects of quantum plasma dynamicsItem Magneto Acoustic Analysis in Ion-Implanted Quantum Semiconductor Plasmas(Library Information Services, COMSATS University Islamabad, Lahore Campus, 2023) Syad Ali Raza; CIIT/SP22-RPH-034/LHR; Dr. Muhammad Jamil; LHR TP 8791In semiconductor quantum plasmas, the instability behavior of magneto-acoustic waves is investigated. We derive the dispersion relation for magneto-acoustic wave behavior ion implantation quantum plasmas semiconductors using Maxwell’s equations and the quantum hydrodynamic model. In an external magnetic field, spin-based exchange correlation effects, Bohm tunneling potential, Fermi statistical pressure, and Landau Quantization. The process of ion-implantation modifies the structure and characteris tics of quantum semiconductors, which are advantageous for the creation of integrated circuits (ICs), metallic nanoparticles, nanoclusters (NCs), digital and storage chips, and their possible uses in a range of technological domains. The semiconductor medium is developed in this work as a plasma system. Numerous factors have a major impact on the growth rate and damping. Due to its many applications, the quantum aspects of plasma physics opened up a new field of study. For example, collision frequency, implantation density, tunneling effect, and external magnetic field. The effects of these parameters have been depicted in graphical representationItem Study of Collective Interactions in Low Beta Dense Plasmas(Library Information Services, COMSATS University Islamabad, Lahore Campus, 2022) Ayesha Rehman; CIIT/SP15-PPH-004/LHR; Dr. Muhammad Jamil; LHR TP 8173The low-beta plasmas reflect the strong magnetic pressure in the comparison of thermal statistical pressure which affects the plasma characteristics and the wave propagation. The collective interactions in low beta plasmas, for the reason of its micro and nano scale applications in the latest technological era, is studied in this research thesis. The electrostatic and electromagnetic modes, their instabilities and growth rates to study new horizon of frequency spectrum is focused in this dissertation. Whenever two charged particles mutually interact, it is done through Coulomb interaction. Though the separation distance among two particles becomes greater than the mean separation distance of particles and as a result the particles immediately interact with many other charged particles in its surroundings and causes collective interactions in plasma. In dense plasmas the charged particles act as a Fermi gas, so the quantum mechanical effects due to significant associated de Broglie length become important while studying the dynamics of charge carriers. The quantum hydrodynamic (QHD) model is helpful for the study of collective interactions in dense plasmas that works well for low beta. The QHD is comparatively simple and captures many of the essential properties of plasma dynamics. This thesis contains three papers. The first paper discussion reveals novel aspects of dusty plasmas as the dust particles can coagulate and grow in size ranging from tens of nanometers to about hundreds of microns size. A semi classical Quantum Hydrodynamic Model (QHD) is employed which includes the quantum effects for plasma electrons in the terms of statistical degenerate pressure, Landau quantization, exchange-correlation potential, and tunneling potential. The low beta plasma characteristics provides the opportunity for the usage of two potential theory in order to derive a complex equation of dispersion of the shear Alfvén wave in quantum dusty magneto plasmas. Analytical simplification of dispersion equation provides the damping rate of the shear Alfvén wave which is verified graphically for a typical set of parameters. It is noticed that the damping rate depends upon the quantum properties of Landau quantization, exchange-correlation, and tunneling potential in addition to the dust radius which modifies the floating potential of the dust particles. Secondly, a system of single wall carbon nano-tubes is considered to study dispersive properties of plasma waves in the presence of uniform axial magnetic field. The impact of quantum characteristics of plasma electrons on the growth rate in the carbon nano- tubes are studied. It is noticed that wave-guide configuration of the plasma system plays a significant role in the growth rate. The graphical analysis depicts the significant role of axial magnetic field in the Landau quantization. Thirdly, an electrostatic wave in a bounded geometry is studied for e-p-i quantum plasmas. The quantum hydrodynamic model is employed to find the dispersion relation xi of waveguide mode. The complex frequency leads to the growth rate and the phase speed in the cylindrical geometry.Item Lower Hybrid Instability with Radiation Pressure Effects in Semiconductor Plasma(Library Information Services, COMSATS University Islamabad, Lahore Campus, 2021) Waseem Abbas; CIIT/SP20-RPH-054/LHR; Dr. Muhammad Jamil; LHR TP 7700Electrostatic modes can widely be categorized as acoustic and hybrid waves. We have studied the excitation of electrostatic, comparatively low frequency volume waves, lower-hybrid waves (LHWs) in semiconductor plasma by using a hydrodynamic model. The Hydrodynamic Model consisting upon fluid equations namely momentum balance equation, equation of continuity and the Poisson’s equation have used to study the physical properties and characteristics of semiconductor plasmas consisting upon electron and holes. Radiation pressure is considered as an exciting source in semiconductor plasma systems. For analytical examination of the linear dispersion relation, we elucidated the fluid equations for semiconductor plasmas. In this thesis, for semiconductor plasmas, we have analyzed the LHWs in the presence of radiation pressure, the thermal effects upon plasma species, in addition to the external magnetic field. For numerical analysis, we have used the assistance of Mathematica or MATLAB.Item Study of Nonlinear Interactions in Dense Plasmas(Library Information Services, COMSATS University Islamabad, Lahore Campus, 2021) Zahid Mir; CIIT/FA14-PPHY-004/LHR; Dr. Muhammad Jamil; LHR TP 7539It is intended here in this thesis to study the nonlinear interactions evolved from the interaction of linear modes in dense plasmas like astrophysical objects, laser produced plasmas and semiconductor plasmas, etc. The dense plasma systems in focus contain electrons, ions and negatively charged dust grains. The constituent modes are electrostatic and electromagnetic in nature. In addition to the coupling mechanism, an electron beam is also considered as an energy source. A multi-fluid model consisting upon momentum balancing equation, equation of continuity, Poisson’s equation and set of Maxwell equations for quantum plasmas is used to diagnose the plasmas analytically. The thesis is composed of two-fold studies of nonlinear interactions based upon the published papers. Firstly, excitation of a beat wave generated by the parametric coupling of two modes of slightly different wavelengths is discussed. The linear analysis of the dispersive nature of the incident (pump) and scattered (sideband) is carried out. A derivation of the nonlinear dispersion expression is carried out due to the linear coupling of the pump and sideband in the assembly of a homogeneous dense dusty magneto-plasmas. This leads to the growth rate of the parametric instability of three waves. Secondly, the nonlinear growth of the parametric instability of electrostatic electron Langmuir wave, produced by the coupling of two waves with slightly different frequencies in semiconductor plasma is discussed. The linearity behaviour of an electrostatic pump (upper-hybrid wave) and electromagnetic sideband (O-mode) in semiconductor quantum plasma is studied. The second order convective term couples the fields of pair modes to derive the nonlinear beat frequency of the resultant perturbation leading to three waves parametric instability in semiconductor quantum plasma system. In both the cases the quantum mechanical effects arising due to degenerate pressure of Fermi gas, quantum tunneling effect, and exchange-correlation potential have been incorporated for the fermions. The instability is analyzed graphically for both cases on varying different parameters.Item Kelvin Helmholtz Instability in Quantum Plasmas(Library Information Services, COMSATS University Islamabad, Lahore Campus, 2021) Muhammad Asif Nazir; FA19-RPH-001; Dr. Muhammad Jamil; LHR TP 7259Kelvin-Helmholtz Instability in Quantum PlasmasItem Oxygen Cyclotron Harmonic Waves in the Inner Magnetosphere(Library Information Services, COMSATS University Islamabad, Lahore Campus, 2019) Abdul Waheed; CIIT/FA17-RPH-037/LHR; Dr. Muhammad Jamil; LHR TP 5726The Banded emission of Oxygen cyclotron harmonic waves has been observed by Van Allen probes in the Earth inner magnetosphere. The general dispersion relation for electrostatic Oxygen cyclotron harmonic waves is derived by using Lerche-Newberger sum rule for Maxwellian and Kappa distributions. Oxygen ion kappa spectral index (𝜅𝑖𝑂) has a significant impact on the Oxygen cyclotron harmonic waves. The quasi Maxwellian behavior is being observed as 𝜅𝑖𝑂 ≥ 5. The curves shift toward the higher value of wavenumber, as the value of 𝜅𝑖𝑂 reduce. There is an increase in super-thermal particles as we reduce the value of 𝜅𝑖𝑂. By decreasing the value of 𝜅𝑖𝑂, the super-thermal particles reduce the frequency , 𝜔𝑝𝑒𝑎𝑘, where the group velocity vanish and the associated 𝑘𝑝𝑒𝑎𝑘 get increase. These cyclotron harmonic waves may be useful for the diagnostic for the velocity distribution characteristics. Oxygen cyclotron harmonic waves can be helpful for the diagnostic of Van Allen Radiation Belts.Item Radiation impact on acoustic waves in Semiconductor Plasmas(Library Information Services, COMSATS University Islamabad, Lahore Campus, 2022) Aashar Sajjad; SP20-RPH-016; Dr. Muhammad Jamil; LHR TP 7686In this thesis, we are discussing the radiation impact on acoustic wave that propagates along z-direction. The acoustic waves due to radiation impact are investigated using the classical multi-fluid approach in classical semiconductor plasma. The quantum effects are not considered in this work. Our model is applied to GaAs semiconductor plasmas. Dispersion relation of acoustic waves is calculated where the effects of the radiation modifies it. Numerically it is observed under different physical conditions, for example, on varying the thermal temperature values and plasma number density etc. For this study we are using multi fluid model. A set of fluid equations are applied to drive the dispersion relation. The said work is done qualitatively and quantitatively using MATHEMATICA.