The Experts below are selected from a list of 70269 Experts worldwide ranked by ideXlab platform
J H Booske - One of the best experts on this subject based on the ideXlab platform.
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Plasma Physics and related challenges of millimeter wave to terahertz and high power microwave generationa
Physics of Plasmas, 2008Co-Authors: J H BooskeAbstract:Homeland security and military defense technology considerations have stimulated intense interest in mobile, high power sources of millimeter-wave (mmw) to terahertz (THz) regime electromagnetic radiation, from 0.1 to 10THz. While vacuum electronic sources are a natural choice for high power, the challenges have yet to be completely met for applications including noninvasive sensing of concealed weapons and dangerous agents, high-data-rate communications, high resolution radar, next generation acceleration drivers, and analysis of fluids and condensed matter. The compact size requirements for many of these high frequency sources require miniscule, microfabricated slow wave circuits. This necessitates electron beams with tiny transverse dimensions and potentially very high current densities for adequate gain. Thus, an emerging family of microfabricated, vacuum electronic devices share many of the same Plasma Physics challenges that are currently confronting “classic” high power microwave (HPM) generators including long-life bright electron beam sources, intense beam transport, parasitic mode excitation, energetic electron interaction with surfaces, and rf air breakdown at output windows. The contemporary Plasma Physics and other related issues of compact, high power mmw-to-THz sources are compared and contrasted to those of HPM generation, and future research challenges and opportunities are discussed.
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Plasma Physics and related challenges of millimeter wave to terahertz and high power microwave generationa
Physics of Plasmas, 2008Co-Authors: J H BooskeAbstract:Homeland security and military defense technology considerations have stimulated intense interest in mobile, high power sources of millimeter-wave (mmw) to terahertz (THz) regime electromagnetic radiation, from 0.1 to 10THz. While vacuum electronic sources are a natural choice for high power, the challenges have yet to be completely met for applications including noninvasive sensing of concealed weapons and dangerous agents, high-data-rate communications, high resolution radar, next generation acceleration drivers, and analysis of fluids and condensed matter. The compact size requirements for many of these high frequency sources require miniscule, microfabricated slow wave circuits. This necessitates electron beams with tiny transverse dimensions and potentially very high current densities for adequate gain. Thus, an emerging family of microfabricated, vacuum electronic devices share many of the same Plasma Physics challenges that are currently confronting “classic” high power microwave (HPM) generators i...
P.k. Shukla - One of the best experts on this subject based on the ideXlab platform.
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nonlinear aspects of quantum Plasma Physics
Physics-Uspekhi, 2010Co-Authors: P.k. Shukla, Bengt EliassonAbstract:Dense quantum Plasmas are ubiquitous in planetary interiors and in compact astrophysical objects (e.g., the interior of white dwarf stars, in magnetars, etc.), in semiconductors and micromechanical systems, as well as in the next-generation intense laser–solid density Plasma interaction experiments and in quantum X-ray free-electron lasers. In contrast to classical Plasmas, quantum Plasmas have extremely high Plasma number densities and low temperatures. Quantum Plasmas are composed of electrons, positrons and holes, which are degenerate. Positrons (holes) have the same (slightly different) mass as electrons, but opposite charge. The degenerate charged particles (electrons, positrons, and holes) obey the Fermi–Dirac statistics. In quantum Plasmas, there are new forces associated with (i) quantum statistical electron and positron pressures, (ii) electron and positron tunneling through the Bohm potential, and (iii) electron and positron angular momentum spin. Inclusion of these quantum forces allows the existence of very high-frequency dispersive electrostatic and electromagnetic waves (e.g., in the hard X-ray and gamma-ray regimes) with extremely short wavelengths. In this review paper, we present theoretical backgrounds for some important nonlinear aspects of wave–wave and wave–electron interactions in dense quantum Plasmas. Specifically, we focus on nonlinear electrostatic electron and ion Plasma waves, novel aspects of three-dimensional quantum electron fluid turbulence, as well as nonlinearly coupled intense electromagnetic waves and localized Plasma wave structures. Also discussed are the phase-space kinetic structures and mechanisms that can generate quasistationary magnetic fields in dense quantum Plasmas. The influence of the external magnetic field and the electron angular momentum spin on the electromagnetic wave dynamics is discussed. Finally, future perspectives of the nonlinear quantum Plasma Physics are highlighted.
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Nonlinear aspects of quantum Plasma Physics
PhysicsUspekhi, 2009Co-Authors: P.k. Shukla, Bengt EliassonAbstract:Dense quantum Plasmas are ubiquitous in planetary interiors and in compact astrophysical objects, in semiconductors and micro-mechanical systems, as well as in the next generation intense laser-solid density Plasma interaction experiments and in quantum x-ray free-electron lasers. In contrast to classical Plasmas, one encounters extremely high Plasma number density and low temperature in quantum Plasmas. The latter are composed of electrons, positrons and holes, which are degenerate. Positrons (holes) have the same (slightly different) mass as electrons, but opposite charge. The degenerate charged particles (electrons, positrons, holes) follow the Fermi-Dirac statistics. In quantum Plasmas, there are new forces associated with i) quantum statistical electron and positron pressures, ii) electron and positron tunneling through the Bohm potential, and iii) electron and positron angular momentum spin. Inclusion of these quantum forces provides possibility of very high-frequency dispersive electrostatic and electromagnetic waves (e.g. in the hard x-ray and gamma rays regimes) having extremely short wavelengths. In this review paper, we present theoretical backgrounds for some important nonlinear aspects of wave-wave and wave-electron interactions in dense quantum Plasmas. Specifically, we shall focus on nonlinear electrostatic electron and ion Plasma waves, novel aspects of 3D quantum electron fluid turbulence, as well as nonlinearly coupled intense electromagnetic waves and localized Plasma wave structures. Also discussed are the phase space kinetic structures and mechanisms that can generate quasi-stationary magnetic fields in dense quantum Plasmas. The influence of the external magnetic field and the electron angular momentum spin on the electromagnetic wave dynamics is discussed.
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a survey of dusty Plasma Physics
Physics of Plasmas, 2001Co-Authors: P.k. ShuklaAbstract:Two omnipresent ingredients of the Universe are Plasmas and charged dust. The interplay between these two has opened up a new and fascinating research area, that of dusty Plasmas, which are ubiquitous in different parts of our solar system, namely planetary rings, circumsolar dust rings, the interplanetary medium, cometary comae and tails, as well as in interstellar molecular clouds, etc. Dusty Plasmas also occur in noctilucent clouds in the arctic troposphere and mesosphere, cloud-to-ground lightening in thunderstorms containing smoke-contaminated air over the United States, in the flame of a humble candle, as well as in microelectronic processing devices, in low-temperature laboratory discharges, and in tokamaks. Dusty Plasma Physics has appeared as one of the most rapidly growing fields of science, besides the field of the Bose–Einstein condensate, as demonstrated by the number of published papers in scientific journals and conference proceedings. In fact, it is a truly interdisciplinary science becaus...
H R Wilson - One of the best experts on this subject based on the ideXlab platform.
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The impact of Plasma Physics on the timescale to a tokamak fusion power plant
Philosophical transactions. Series A Mathematical physical and engineering sciences, 2019Co-Authors: H R WilsonAbstract:Some of the main Plasma Physics challenges associated with achieving the conditions for commercial fusion power in tokamaks are reviewed. The confinement quality is considered to be a key factor, h...
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integrated Plasma Physics modelling for the culham steady state spherical tokamak fusion power plant
Nuclear Fusion, 2004Co-Authors: H R Wilson, R J Akers, D Applegate, R A Cairns, J P Christiansen, J W Connor, G F Counsell, A Dnestrovskij, W Dorland, M J HoleAbstract:Integrated modelling of important Plasma Physics issues related to the design of a steady-state spherical tokamak (ST) fusion power plant is described. The key is a steady-state current drive, and 92% of this is provided by a combination of bootstrap and diamagnetic currents, both of which have a substantial toroidal component in a ST. The remaining current is to be provided by either neutral beam injection or radio-frequency waves, and various schemes for providing this are discussed and quantified. The desire to achieve a high bootstrap current drives the design to high Plasma pressure, ? (normalized to the magnetic field pressure), and high elongation. Both these requirements have implications for ideal magneto-hydrodynamic instability which are discussed. Confinement is addressed both through comparison with the recent scaling laws developed from the conventional tokamak database and self-consistent one-dimensional modelling of the transport processes. This modelling shows that the power required for the current drive (~50?MW) is sufficient to heat the Plasma to a regime where more than 3?GW of fusion power is produced, taking into account the dilution due to He ash and prompt ?-particle losses, which are small. A preliminary study of the micro-instabilities, which may be responsible for the turbulent transport is provided. Given assumptions about the particle confinement, we make estimates of the fuelling requirements to maintain the steady state. Finally, the power loading due to the exhaust is derived using theory-based scalings for the scrape-off layer width.
Christine Charles - One of the best experts on this subject based on the ideXlab platform.
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grand challenges in low temperature Plasma Physics
Frontiers in Physics, 2014Co-Authors: Christine CharlesAbstract:INTRODUCTION A Plasma is a hot ionized gas and classification of this fourth state of matter can be initially done using the basic concept of temperature. A prime example is the Sun which exhibits a very hot Plasma in its core with temperatures of about 1.5 × 107 K (a result of fusion reactions with a proton density of ∼1026 cm−3) and cooler surface temperatures of about 6000 K [1]: the Solar wind originates from the Solar Corona, expands into the universe and impacts the Earth’ magnetosphere and ionosphere, the two Plasma layers surrounding Earth’s gaseous atmosphere. Aurorae in the Northern and Southern skies near the magnetic poles are examples of this interaction. The electron density in the ionosphere is low (104–106 cm−3) and the background neutral gas density is also low (about 108 cm−3 or 3 × 109 Torr at 300 km altitude) approaching the “space-like” environment created in laboratories to develop and test hardware for space use (i.e., satellites and payloads). At the surface of the Earth lightning strikes of a storm are naturally occurring Plasmas operating near atmospheric pressure (neutral density of about 2 × 1019cm−3) with large electron densities (about 1015– 1017 cm−3) characteristic of streamers, arcs and filamentary discharges. The temperatures and densities of neutral and charged particles are critical parameters affecting the physical mechanisms within the Plasma such as particle transport and collisional processes [2] and their range spans many orders of magnitude, opening doors to an extremely wide range of Plasma applications. Plasmas in which fusion reactions take place are often referred to as “hot” Plasmas. The high-temperature Plasma community has a well-defined aim of triggering and controlling fusion Plasmas (as can be found in the Sun’s core) for energy production, with various worldwide large scale programs or experiments in place (i.e., the International Thermonuclear Experimental Reactor ITER, the National Ignition Facility ICF. . .) [3]. Hot Plasmas in space also include relativistic Plasmas (highest electron temperatures) and quantum Plasmas (highest electron densities). All other Plasmas are classified as low-temperature or “cold” Plasmas: those gaseous Plasmas or electrical discharges have been successfully harnessed and studied in the laboratory since the 1920s and in space using satellites since the 1960s. The latter two Plasma examples essentially sit at the opposite ends of the “cold” Plasma spectrum. The wide range of available Plasma parameters has largely contributed to the long and expanding list of Plasma applications as a result of both scientific and economic drivers: the temperature range of the neutral and/or ionized species allow heat and particle control to burn, melt, cut, coat, grow materials from the macroscopic to the microand nanoscale via “so called” Plasma processes. Amongst thousands of Plasma applications processes, a few examples are presented to show the past, present and future key role cold Plasma Physics must play in addressing the challenges facing the modern world: predicted energy crisis, environmental issues and ecosystems, global climate variation, population growth and biomedical concerns. In addressing those issues we must better understand the Physics of the atmosphere, ionosphere and magnetosphere, the Physics of the Plasma interacting with a boundary and develop new clean sources of energy.
Vasilios Dimitriou - One of the best experts on this subject based on the ideXlab platform.
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innovative education and training in high power laser Plasmas powerlaps for Plasma Physics high power laser matter interactions and high energy density Physics experimental diagnostics and simulations
High Power Laser Science and Engineering, 2020Co-Authors: J Pasley, Georgia Andrianaki, Andreas Baroutsos, D Batani, E P Benis, Donna Cook, J I Apinaniz, A Ciardi, Massimo De Marco, Vasilios DimitriouAbstract:The second and final year of the Erasmus Plus programme ‘Innovative Education and Training in high power laser Plasmas’, otherwise known as PowerLaPs, is described. The PowerLaPs programme employs an innovative paradigm in that it is a multi-centre programme, where teaching takes place in five separate institutes with a range of different aims and styles of delivery. The ‘in-class’ time is limited to 4 weeks a year, and the programme spans 2 years. PowerLaPs aims to train students from across Europe in theoretical, applied and laboratory skills relevant to the pursuit of research in laser Plasma interaction Physics and inertial confinement fusion. Lectures are intermingled with laboratory sessions and continuous assessment activities. The programme, which is led by workers from the Hellenic Mediterranean University and supported by co-workers from the Queen’s University Belfast, the University of Bordeaux, the Czech Technical University in Prague, Ecole Polytechnique, the University of Ioannina, the University of Salamanca and the University of York, has just finished its second and final year. Six Learning Teaching Training activities have been held at the Queen’s University Belfast, the University of Bordeaux, the Czech Technical University, the University of Salamanca and the Institute of Plasma Physics and Lasers of the Hellenic Mediterranean University. The last of these institutes hosted two 2-week-long Intensive Programmes, while the activities at the other four universities were each 5 days in length. In addition, a ‘Multiplier Event’ was held at the University of Ioannina, which will be briefly described. In this second year, the work has concentrated on training in both experimental diagnostics and simulation techniques appropriate to the study of Plasma Physics, high power laser matter interactions and high energy density Physics. The nature of the programme will be described in detail, and some metrics relating to the activities carried out will be presented. In particular, this paper will focus on the overall assessment of the programme.
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innovative education and training in high power laser Plasmas powerlaps for Plasma Physics high power laser matter interactions and high energy density Physics theory and experiments
High Power Laser Science and Engineering, 2019Co-Authors: J Pasley, Georgia Andrianaki, Andreas Baroutsos, D Batani, E P Benis, M Borghesi, E L Clark, Donna Cook, E Dhumieres, Vasilios DimitriouAbstract:The Erasmus Plus programme ‘Innovative Education and Training in high power laser Plasmas’, otherwise known as PowerLaPs, is described. The PowerLaPs programme employs an innovative paradigm in that it is a multi-centre programme where teaching takes place in five separate institutes with a range of different aims and styles of delivery. The ‘in class’ time is limited to four weeks a year, and the programme spans two years. PowerLaPs aims to train students from across Europe in theoretical, applied and laboratory skills relevant to the pursuit of research in laser–Plasma interaction Physics and inertial confinement fusion (ICF). Lectures are intermingled with laboratory sessions and continuous assessment activities. The programme, which is led by workers from the Technological Educational Institute (TEI) of Crete, and supported by co-workers from the Queen’s University Belfast, the University of Bordeaux, the Czech Technical University in Prague, Ecole Polytechnique, the University of Ioannina, the University of Salamanca and the University of York, has just completed its first year. Thus far three Learning Teaching Training (LTT) activities have been held, at the Queen’s University Belfast, the University of Bordeaux and the Centre for Plasma Physics and Lasers (CPPL) of TEI Crete. The last of these was a two-week long Intensive Programme (IP), while the activities at the other two universities were each five days in length. Thus far work has concentrated upon training in both theoretical and experimental work in Plasma Physics, high power laser–matter interactions and high energy density Physics. The nature of the programme will be described in detail and some metrics relating to the activities carried out to date will be presented.