This work aims to review the progress in understanding the underlining physics of pulsar glitches: beginning from the pedagogical development of the subject to eventually motivating the use of AdS/CFT techniques in studying a certain class of condensed matter systems. The foundation of this work is built upon the Gross Pitaevskii (GP) model of super-fluidity applied to the interior matter of neutron stars, where the condensate wave function acts as the order parameter of the macroscopic coherence theory. The excitation modes of the field equations are found to be solitonic vortices, which then go on to present a theoretical basis to the plausible theories of pulsar glitches involving vortex dynamics. The second major thrust of this thesis is in reviewing the application of AdS/CFT in study of strongly-coupled condensed matter systems, with special attention to the models of holographic superfluidity that admit vortex-like solutions. The basic identification of the characteristic free energy configuration of global vortices in the AdS/CFT prescription enables to motivate its use in studying the pulsar glitch mechanism. The last part of this work traces the conclusions of this review and attempts to present the current state-of-progress of the field with its extensive domain of purview and open lines of inquiry.

Includes bibliographical references. / A number of solutions to the dark energy problem have been proposed in literature, the simplest is the cosmological constant A. The cosmological constant lacks theoretical explanation for its extremely small value, thus dark energy is more generally modelled as a quintessence scalar field rolling down a flat potential.

Includes abstract. / Includes bibliographical references (leaves 83-89). / In the standard model of the Universe, the cosmos has only accelerated once since decoupling and only recently, at around a redshift of z ̃ 0.5 as supported by different observations including Type Ia Supernovae (SNIa), the Cosmic Microwave Background (CMB), Large Scale Structure (LSS), and Weak Lensing (WL). This confirmation however, lacks a fundamental physics explanation. The hypothetical form of energy termed 'dark energy' (DE) assumed to account for that acceleration behavior, is still mysterious and why its dominance only occurred recently is a profound problem widely known as the coincidence problem. So far all attempts for resolving the coincidence the problem have been unsatisfactory. Here we investigate a possible solution to the coincidence problem in the form of multiples phases of acceleration (MPA). If there were more than one phase of acceleration between now and decoupling, then the current phase of acceleration would be much less special, alleviating the coincidence problem. We use a modified Markov Chain Monte Carlo (MCMC) technique together with the WMAP five year TT data to search for parameters allowing a second phase of acceleration. Despite extensive search we find no models that simultaneously fit the WMAP data and yield a second phase of acceleration, ruling out this particular set of models as the solution to the coincidence problem.

Ionospheric irregularities are small-scale plasma density structures driven by instabilities arising from combinations of plasma drifts, density gradients, and electric fields. These irregularities can cause mid-latitude GPS scintillations, characterized by amplitude and phase fluctuations that degrade communication link performance. However, the processes behind these scintillations remain poorly understood due to limited models and observations. This thesis explores the Gradient Drift Instability (GDI) and Kelvin-Helmholtz Instability (KHI) to understand their potential roles in driving mid-latitude ionospheric turbulence and irregularities.par Initial investigations involved a two-dimensional (2D) numerical model to study density irregularities in the Subauroral Polarization Streams (SAPS). This model analyzed the turbulence spectra of the GDI. Previous work identified GDI as a key mechanism for generating ionospheric irregularities in SAPS, emphasizing the role of background electric fields and velocity shear in shaping turbulence. Using a fixed background density profile and varying latitudinal velocity profiles, the model explored how velocity shear location and neutral wind direction affect turbulence spectra of the GDI and their associated power laws. Turbulence spectra for cases with no velocity profile and with different neutral wind directions are analyzed. The impact of velocity shear is studied by translating the velocity shear location relative to the density gradient. Numerical spectral analysis results are presented and compared to recent experimental observations.par A newly developed three-dimensional (3D) electrostatic fluid model extends these investigations to capture the behavior and evolution of ionospheric plasma clouds. Historically, these artificial plasma clouds have served as a case study for understanding irregularity evolution in the textit{F} region. The GDI, driven by the (mathbf{E}timesmathbf{B}) drift, was identified as the primary mechanism causing rapid structuring of these clouds, cascading energy to smaller scales transverse to the magnetic field. Nonlinear 2D and 3D simulations were conducted across three regimes: highly collisional ((approx 200 , si{km})), collisional ((approx 300 , si{km})), and inertial ((approx 450 , si{km})). The results show that structuring evolves more slowly in 3D simulations due to additional dynamics, particularly the ambipolar potential in the current closure equation, which introduces an azimuthal "twist" around the magnetic field axis. In the collisional regime, this twist disrupts flute-like perturbations ((k_{parallel} neq 0)), while in the inertial regime, the cloud rapidly diffuses, retaining flute-like perturbations ((k_{parallel} = 0)).par Building on this 3D model, altitude-dependent neutral and plasma density profiles were incorporated to better represent ionospheric parallel dynamics. This enhanced model captures ionospheric irregularities, their generation mechanisms, and their altitudinal variations. It was used to examine the dominance and interplay of GDI and KHI within SAPS across varying altitudes, advancing our understanding of mid- to high-latitude ionospheric turbulence processes.par This work was supported by NASA under Grant Number $NASAMAG16_2-0050$, the Kevin T. Crofton Department of Aerospace and Ocean Engineering, and the Bradley Department of Electrical Engineering at Virginia Tech. / Doctor of Philosophy / Ionospheric turbulence, or disturbances in the plasma in the ionosphere, are not entirely understood by scientists. However, they are of significant practical importance and can adversely affect radio communication and GPS signals. For example, when GPS signals travel through turbulent regions in the ionosphere, position estimates become less accurate. As a result, understanding the generation mechanisms behind turbulence in the ionosphere is critical in improving the accuracy of GPS/GNSS signals. Subauroral polarization streams (SAPS) are regions in the ionosphere with large westward flow of plasma that varies with latitude. Ionospheric turbulence has been observed in SAPS, and is hypothesized to be caused by plasma instabilities such as the gradient drift instability (GDI). Numerical simulations of these phenomena help shed light on how turbulence is generated in the near-Earth space environment. In this research, a 3D model is developed to simulate how turbulence evolves across different altitudes in the ionosphere. By incorporating realistic plasma and neutral density conditions, this work provides new insights into the role of GDI and other instabilities in shaping turbulence in SAPS. Finally, these simulations are compared to experimental radar data to improve our understanding of such ionospheric processes.

No description available.

Australia's space activities since the early sixties have been science-oriented and uncoordinated. As a result, Australia has been unable to develop a long-term sustainable domestic technological capability; with industry being dependent on government funding for its involvement in the nation's space plan. This thesis examines public policy aspects focussing on technology independence that is the building of competencies for the sustainable development of an industry. It compares national technological development by relating Australia's recent space-related successes and failures to those of other nations (especially selected Asian countries and Israel). The overarching research problem addressed within this thesis examined the Australian national space policy and strategy since 1984.It investigated why the Australian Space Industry Development Strategy was not a successful influence on the development of a long-term sustainable national technological base or on the establishment of a viable commercial space-related industry in Australia. The research included the development of a strategic multilevel planning system involving a network innovation model into a nation's space science and technology policy development. The outcomes of the research reported in the thesis are discussed. The level of technological capability and capacity is a direct, inversely related factor to an increase in the degree in technology dependency. Australia needs a change of philosophy by accepting the global challenge through defining and supporting, within a national strategic planning, a national space strategy that incorporates network innovation concepts: a concept that must involve a balanced supply (science) and demand (commercial) characteristics of an innovation network system. / Doctor of Philosophy (PhD) (Management)

The waves of military innovation have changed the principle and concept of traditional military warfare. The command of the space, succeeding the power of the land in the early days, the Sea superiority in the 18th century, the command of land in the 19th century, the Air superiority and the Information dominance in the 20th century has become a totally new concept of military command. The space warfare, for the purpose of controlling the space, finally comes on the stage. Under the influence of the competitors between the U.S.A. and U.S.S.R. in the field of military prowess, China started its development of space technology in 1956. After 50 years passed, Chain has become a nation of potential space warfare. Its prowess in space warfare is found on its advanced and firmly established space science and technology. Following the U.S.A. and the U.S.S.R. China has build up its space army which aims at seizing the dominion of the future space warfare. Evidently, every great nation, for the purposes of gaining supreme authority in the warfare in this century, has fully engaged in building up its prowess in the command of the space. This essay aims at study China¡¦s development in space warfare which is founded on the concept of the scramble for the command of the space. Such studies help to understand China¡¦s recognition of space warfare, its development of space army, its research and development in space science and technology, its present structure and equipment for space warfare and its ambitions and directions in the future space warfare . The study of this essay, which are based on several perspectives, will help to provide a referential background for the observation of the future development of space warfare of China.

This thesis examines user interaction with instrumentation in the specific context of space science. It gathers together existing practice in machine interfaces with a look at potential future usage and recommends a new approach to space science projects with the intention of maximising their science return. It first takes a historical perspective on user interfaces and ways of defining and measuring the science return of a space instrument. Choices of research methodology are considered. Implementation details such as the concepts of usability, mental models, affordance and presentation of information are described, and examples of existing interfaces in space science are given. A set of parameters for use in analysing and synthesizing a user interface is derived by using a set of case studies of diverse failures and from previous work. A general space science user analysis is made by looking at typical practice, and an interview plus persona technique is used to group users with interface designs. An examination is made of designs in the field of astronomical instrumentation interfaces, showing the evolution of current concepts and including ideas capable of sustaining progress in the future. The parameters developed earlier are then tested against several established interfaces in the space science context to give a degree of confidence in their use. The concept of a simulator that is used to guide the development of an instrument over the whole lifecycle is described, and the idea is proposed that better instrumentation would result from more efficient use of the resources available. The previous ideas in this thesis are then brought together to describe a proposed new approach to a typical development programme, with an emphasis on user interaction. The conclusion shows that there is significant room for improvement in the science return from space instrumentation by attention to the user interface.

No description available.

Prior to launch, space craft instruments need to be tested in a relevant environment to prove operational functionality. Thus, we have developed an ion source to stimulate thermal plasma instruments in a vacuum chamber. This dissertation presents the mechanical design of the source, simulations of the potentials and charged particle trajectories in and around the source, and vacuum chamber measurements of the emitted ion beam. Once the ion source is understood, it is successfully used to test a typical ion instrument. Further aspects of the ion source, efficiency, thermionic filament emission, and collision frequencies are also discussed. / Doctor of Philosophy / Satellites have become a critical resource for business and governments. The study of the high edge of the earth’s atmosphere, where satellites operate, is difficult because the physics of this region is so complex. More measurements of the upper atmosphere are needed to understand exactly how it works and improve the computer models simulating the atmosphere. The instruments used to measure this region need to be validated before they are launched. This dissertation describes the design and testing of an ion source device that can produce charged particles in a very low pressure environment, such as a vacuum chamber, to create conditions similar to those an instrument would encounter in orbit. Computer simulations and physical tests of the source are presented, compared, and found to match. Finally, an actual satellite instrument is successfully validated with the source.