Dual-keel electrodynamic maglev system
He, J.; Wang, Z.; Rote, D.M.; Coffey, H.T.; Hull, J.R.; Mulcahy, T.M.; Cai, Y.
1995-12-31
A propulsion and stabilization system with a plurality of superconducting magnetic devices affixed to the dual-keels of a vehicle, where the superconducting magnetic devices produce a magnetic field when energized. The system also includes a plurality of figure-eight shaped null-flux coils affixed to opposing vertical sides of slots in a guideway. The figure-eight shaped null-flux coils are vertically oriented, laterally cross-connected in parallel, longitudinally connected in series, and continue the length of the vertical slots providing levitation and guidance force. An external power source energizes the figure-eight shaped null-flux coils to create a magnetic traveling wave that interacts with the magnetic field produced by the superconducting magnets to impart motion to the vehicle.
Dual-keel electrodynamic maglev system
He, Jianliang; Wang, Zian; Rote, Donald M.; Coffey, Howard T.; Hull, John R.; Mulcahy, Thomas M.; Cal, Yigang
1996-01-01
A propulsion and stabilization system with a plurality of superconducting magnetic devices affixed to the dual-keels of a vehicle, where the superconducting magnetic devices produce a magnetic field when energized. The system also includes a plurality of figure-eight shaped null-flux coils affixed to opposing vertical sides of slots in a guideway. The figure-eight shaped null-flux coils are vertically oriented, laterally cross-connected in parallel, longitudinally connected in series, and continue the length of the vertical slots providing levitation and guidance force. An external power source energizes the figure-eight shaped null-flux coils to create a magnetic traveling wave that interacts with the magnetic field produced by the superconducting magnets to impart motion to the vehicle.
Dual-keel electrodynamic maglev system
He, J.L.; Wang, Z.; Rote, D.M.; Coffey, H.T.; Hull, J.R.; Mulcahy, T.M.; Cal, Y.
1996-12-24
A propulsion and stabilization system is disclosed with a plurality of superconducting magnetic devices affixed to the dual-keels of a vehicle, where the superconducting magnetic devices produce a magnetic field when energized. The system also includes a plurality of figure-eight shaped null-flux coils affixed to opposing vertical sides of slots in a guideway. The figure-eight shaped null-flux coils are vertically oriented, laterally cross-connected in parallel, longitudinally connected in series, and continue the length of the vertical slots providing levitation and guidance force. An external power source energizes the figure-eight shaped null-flux coils to create a magnetic traveling wave that interacts with the magnetic field produced by the superconducting magnets to impart motion to the vehicle. 6 figs.
Study of Japanese electrodynamic-suspension maglev systems
He, J.L.; Rote, D.M.; Coffey, H.T.
1994-04-01
This report presents the results of a study of the Japanese MLU magnetic-levitation (maglev) system. The development of the MLU system is reviewed, and the dynamic circuit model then is introduced and applied to the figure-eight-shaped null-flux coil suspension system. Three different types of figure-eight-shaped null-flux suspension systems are discussed in detail: (1) the figure-eight-shaped null-flux coil suspension system without cross-connection; (2) the combined suspension and guidance system; and (3) the combined propulsion, levitation, and guidance system. The electrodynamic-suspension maglev systems developed in Japan seem to be very promising and could result in a commercial application in the near future.
Adaptive momentum management for the dual keel Space Station
NASA Technical Reports Server (NTRS)
Hopkins, M.; Hahn, E.
1987-01-01
The report discusses momentum management for a large space structure with the structure selected configuration being the Initial Orbital Configuration of the dual-keel Space Station. The external torques considered were gravity gradient and aerodynamic torques. The goal of the momentum management scheme developed is to remove the bias components of the external torques and center the cyclic components of the stored angular momentum. The scheme investigated is adaptive to uncertainties of the inertia tensor and requires only approximate knowledge of principal moments of inertia. Computational requirements are minimal and should present no implementation problem in a flight-type computer. The method proposed is shown to be effective in the presence of attitude control bandwidths as low as 0.01 radian/sec.
Dynamic characteristics of two 300 kW class dual keel space station concepts
NASA Technical Reports Server (NTRS)
Dorsey, J. T.; Sutter, T. R.; Lake, M. S.; Cooper, P. A.
1986-01-01
Results from an investigation of the dynamic behavior of a 300 kW class solar dynamic powered, dual kell space station are presented. The purpose of the investigation was to determine and assess the influence of space station truss bay size on station controllability during rigid body attitude adjustment and orbit reboost maneuvers. The dual keel space station concept is defined and two finite element models (one which has a truss bay size of 5m and another with a truss bay size of 9 feet) are described. Rigid and flexible body characteristics of the two space station models are also presented. Finally, results from a transient response analysis, where the stations are subjected to an orbit reboost maneuver, are summarized.
Dynamic stability of repulsive-force maglev suspension systems
Cai, Y.; Rote, D.M.; Mulcahy, T.M.; Wang, Z.
1996-11-01
This report summarizes the research performed on maglev vehicle dynamic stability at Argonne National Laboratory during the past few years. It also documents both measured and calculated magnetic-force data. Because dynamic instability is not acceptable for any commercial maglev system, it is important to consider this phenomenon in the development of all maglev systems. This report presents dynamic stability experiments on maglev systems and compares the results with predictions calculated by a nonlinear-dynamics computer code. Instabilities of an electrodynamic-suspension system type vehicle model were obtained by experimental observation and computer simulation of a five-degree-of-freedom maglev vehicle moving on a guideway that consists of a pair of L-shaped aluminum conductors attached to a rotating wheel. The experimental and theoretical analyses developed in this study identify basic stability characteristics and future research needs of maglev systems.
NASA Astrophysics Data System (ADS)
Johnson, L. R.; Giese, R. F.
1988-04-01
The potential for magnetically levitated (MAGLEV) vehicles is discussed as a means of both inter-city travel and a technology option to relieve the growing problem of air traffic congestion. A brief summary is presented of the two primary MAGLEV concepts: (1) the attractive-force, electromagnetic system (EMS) and (2) the repulsive-force, electrodynamic system (EDS), and continues with a discussion of the advantages, potential for reduced costs and higher reliability, that the newly-discovered, high-temperature superconductors offer for EDS MAGLEV vehicles. A summary of the current status of worldwide MAGLEV research is presented, followed by a discussion of the resurgence of US interest in MAGLEV. An analysis of air-traffic congestion suggests that MAGLEV can substitute for short-to-medium distance air travel. By promoting MAGLEV as an airline technology, airlines can retain their familiar hub-and-spoke systems with MAGLEVs an integral part of the spoke portion. A preliminary analysis suggests that MAGLEV capital costs are likely to be comparable to those of interstate highways, and use of MAGLEVs can delay the need for new airport construction. For each short-to-medium flight diverted to MAGLEV, an airline can substitute a longer flight. The short-haul flights use an inordinate amount of fuel, which is a major component of airline operating costs. MAGLEV energy consumption would be significantly less and would not have the emissions associated with petroleum fuel. Finally, passengers should benefit from MAGLEV technology: travel options will be extended, delays will be reduced, and costs for inter-city travel will be reduced.
ERIC Educational Resources Information Center
Ruiz, Ernest; And Others
1991-01-01
Presented are classroom activities in which students explore the potential use of magnetic levitation for transportation purposes. The advantages of using a MagLev transportation system instead of conventional trains are discussed. Directions for designing and building a MagLev track and circuit are provided. (KR)
Powell, Jim
2016-03-17
2016 marks the 50th anniversary of the first published paper on Maglev by retired Brookhaven Lab scientists Gordon Danby and James Powell. The two researchers invented and patented maglev technology — the suspension, guidance, and propulsion of vehicles by magnetic forces.
Powell, Jim
2016-10-19
2016 marks the 50th anniversary of the first published paper on Maglev by retired Brookhaven Lab scientists Gordon Danby and James Powell. The two researchers invented and patented maglev technology â the suspension, guidance, and propulsion of vehicles by magnetic forces.
Rote, D.M.
1993-11-01
Factors that have led to a reawakening of national interest in maglev technology in the United States are discussed. The development of the National Maglev program, its findings, and the four maglev design concepts resulting from the System Concept Definition study are reviewed. Technical requirements for the SCD contractors and for the Prototype Development Program are compared. Some legislative background information is given, with a review of the most important maglev legislation. Plans for the National Maglev Prototype Development Program are discussed, and activities related to maglev at Argonne National Laboratory are summarized.
Publications on maglev technologies
He, J.L.; Coffey, H.T.; Rote, D.M.; Wang, Z.
1991-12-01
Magnetically levitated passenger-transportation vehicles, using attractive and repulsive magnetic forces, are currently in the development or prototype-revenue stages in Japan and Germany. The basic principles of these technologies have been understood for several decades, but their practical applications awaited advances in high-power electronic devices, modern controls, superconducting magnets, and improvements in our transportation infrastructures. A considerable amount of work was devoted to magnetic-levitation (maglev) transportation system in the late 1960s and the 1970s. Detailed development was sustained primarily in Germany and Japan. This listing of publications was begun as the initial phase of a design study for a maglev development facility sponsored by the State of Illinois. The listing has been continually updated under programs sponsored by the Federal Railroad Administration and the US Army Corps of Engineers. In 1991, the National Maglev Initiative issued 27 contracts for the study of technical issues related to maglev and four contracts for the definition of maglev systems. In December 1991, the Intermodal Surface Transportation Efficiency Act was enacted, mandating the development of a US-designed maglev system in a six-year period. This listing is offered as an aid to those working on these projects, to help them locate technical papers on relevant technologies. The design and installation of a maglev transportation system will require the efforts of workers in many disciplines, from electronics to economics to safety. Accordingly, the references have been grouped in 14 different sections to expedite review of the listing. In many case, the references are annotated to indicate the general content of the papers. Abstracts are not available. A list of information services from which the listed documents might be obtained and an author index are provided.
Survey of foreign maglev systems
He, J.L.; Rote, D.M.; Coffey, H.T.
1992-07-01
Magnetic levitation (maglev) transportation systems represent an innovative technology that promises to provide pollution-free, contact-free, high-speed ground transportation for the twenty-first century. Great interest in maglev systems has been developing in the United States over the past two years under the auspices of the US National Maglev Initiative. The objective of the survey presented in this report is to provide the US maglev community with information on various maglev concepts that were developed in foreign countries over the past two decades. The main maglev systems included in the survey are the German Transrapid series and the M-Bahn, the Japanese HSST and MLU series, and the British Birmingham. Each maglev system is introduced and discussed according to its type, historical development, unique features, current status, and future prospects. Advantages and disadvantages of each system are briefly noted.
ERIC Educational Resources Information Center
Kraftmakher, Yaakov
2008-01-01
An experiment and a demonstration concerning transport by magnetic levitation (Maglev) are described. The lift, drag and radial forces on a magnet placed over a rotating conducting disc are measured versus the rotation frequency. The experiment relates to important topics of electromagnetism and could be a useful addition to the undergraduate…
Rote, D. M.; Johnson, L. R.; Energy Systems
2003-01-01
Putting Maglev on Track' (Issues, Spring 1990) observed that growing airline traffic and associated delays were already significant and predicted that they would worsen. The article argued that a 300-mile-per-hour (mph) magnetic levitation (maglev) system integrated into airport and airline operations could be a part of the solution. Maglev was not ready for prime time in 1990, but it is now.
Controls of maglev suspension systems
Cai, Y.; Zhu, S.; Chen, S.S.; Rote, D.M.
1993-06-01
This study investigates alternative control designs of maglev vehicle suspension systems. Active and semi-active control law designs are introduced into primary and secondary suspensions of maglev vehicles. A one-dimensional vehicle with two degrees of freedom, to simulate the German Transrapid Maglev System, is used for suspension control designs. The transient and frequency responses of suspension systems and PSDs of vehicle accelerations are calculated to evaluate different control designs. The results show that active and semi-active control designs indeed improve the response of vehicle and provide an acceptable ride comfort for maglev systems.
Maglev system design considerations
Coffey, H.T.
1991-01-01
Although efforts are now being made to develop magnetic levitation technologies in the United States, they have been underway for two decades in Germany and Japan. The characteristics of maglev systems being considered for implementation in the United States are speculative. A conference was held at Argonne National Laboratory on November 28--29, 1990, to discuss these characteristics and their implications for the design requirements of operational systems. This paper reviews some of the factors considered during that conference.
Zhu, S.; Cai, Y.; Rote, D. M.; ...
1998-01-01
Magnetic damping is one of the important parameters that control the response and stability of maglev systems. An experimental study to measure magnetic damping directly is presented. A plate attached to a permanent magnet levitated on a rotating drum was tested to investigate the effect of various parameters, such as conductivity, gap, excitation frequency, and oscillation amplitude, on magnetic damping. The experimental technique is capable of measuring all of the magnetic damping coefficients, some of which cannot be measured indirectly.
Computation of magnetic suspension of maglev systems using dynamic circuit theory
NASA Astrophysics Data System (ADS)
He, J. L.; Rote, D. M.; Coffey, H. T.
1992-05-01
Dynamic circuit theory is applied to several magnetic suspensions associated with maglev systems. These suspension systems are the loop-shaped coil guideway, the figure-eight-shaped null-flux coil guideway, and the continuous sheet guideway. Mathematical models, which can be used for the development of computer codes, are provided for each of these suspension systems. The differences and similarities of the models in using dynamic circuit theory are discussed in the paper. The paper emphasizes the transient and dynamic analysis and computer simulation of maglev systems. In general, the method discussed here can be applied to many electrodynamic suspension system design concepts. It is also suited for the computation of the performance of maglev propulsion systems. Numerical examples are presented in the paper.
US maglev: Status and opportunities
Coffey, H.T.
1992-01-01
Recognizing the development of maglev systems in Germany and Japan, and the growing congestion, air pollution and energy consumption resulting from our current transportation system, the United States, in 1990, embarked on a program to evaluate the potential usefulness of these systems in the US. In this paper, the utility of maglev systems in alleviating some of these problems, progress in the current program, and opportunities for participation by the superconductivity and cryogenic communities are discussed.
US maglev: Status and opportunities
Coffey, H.T.
1992-09-01
Recognizing the development of maglev systems in Germany and Japan, and the growing congestion, air pollution and energy consumption resulting from our current transportation system, the United States, in 1990, embarked on a program to evaluate the potential usefulness of these systems in the US. In this paper, the utility of maglev systems in alleviating some of these problems, progress in the current program, and opportunities for participation by the superconductivity and cryogenic communities are discussed.
NASA Technical Reports Server (NTRS)
Knolle, Ernst G.
1994-01-01
This maglev crude oil pipeline consists of two conduits guiding an endless stream of long containers. One conduit carries loaded containers and the other empty returns. The containers are levitated by permanent magnets in repulsion and propelled by stationary linear induction motors. The containers are linked to each other in a manner that allows them, while in continuous motion, to be folded into side by side position at loading and unloading points. This folding causes a speed reduction in proportion to the ratio of container diameter to container length. While in side by side position, containers are opened at their ends to be filled or emptied. Container size and speed are elected to produce a desired carrying capacity.
US Advanced Freight and Passenger MAGLEV System
NASA Technical Reports Server (NTRS)
Morena, John J.; Danby, Gordon; Powell, James
1996-01-01
Japan and Germany will operate first generation Maglev passenger systems commercially shortly after 2000 A.D. The United States Maglev systems will require sophisticated freight and passenger carrying capability. The U.S. freight market is larger than passenger transport. A proposed advanced freight and passenger Maglev Project in Brevard County Florida is described. Present Maglev systems cost 30 million dollars or more per mile. Described is an advanced third generation Maglev system with technology improvements that will result in a cost of 10 million dollars per mile.
NASA Astrophysics Data System (ADS)
Hanasoge, Aravind M.
Vehicle-guideway interaction studies of Magnetically Levitated (Maglev) vehicles indicate that structural flexibility can adversely affect the overall stability and performance of such systems. This is one of the reasons why guideways are generally made very rigid. This in turn leads to increased cost of the overall system since guideway construction forms a significant portion of the overall cost. In this dissertation, the influence of structural flexibility on the stability of Electromagnetic Suspension (EMS) Maglev systems is studied. It is shown how inherently unstable and flexible structure EMS Maglev systems can achieve guaranteed stability by using collocated actuators and sensors, along with de-centralized Proportional plus Derivative (PD) controllers. These results are valid even in the presence of Track/Guideway flexibility. A detailed dynamic model is developed for the EMS Maglev demonstration system (Test Bogie) currently under research and development at Old Dominion University (ODU). This model incorporates structural dynamics with flexible modes of vibration, non-linear electrodynamics, feedback controllers, discrete time implementation, noise filters and disturbance inputs. This model is validated via real time experimental testing. The model thus validated is used for simulation case studies involving levitation and lateral disturbance, lateral control, and centralized control.
NASA Astrophysics Data System (ADS)
Mead, Carver A.
2002-08-01
In this book Carver Mead offers a radically new approach to the standard problems of electromagnetic theory. Motivated by the belief that the goal of scientific research should be the simplification and unification of knowledge, he describes a new way of doing electrodynamics--collective electrodynamics--that does not rely on Maxwell's equations, but rather uses the quantum nature of matter as its sole basis. Collective electrodynamics is a way of looking at how electrons interact, based on experiments that tell us about the electrons directly. (As Mead points out, Maxwell had no access to these experiments.) The results Mead derives for standard electromagnetic problems are identical to those found in any text. Collective electrodynamics reveals, however, that quantities that we usually think of as being very different are, in fact, the same--that electromagnetic phenomena are simple and direct manifestations of quantum phenomena. Mead views his approach as a first step toward reformulating quantum concepts in a clear and comprehensible manner. The book is divided into five sections: magnetic interaction of steady currents, propagating waves, electromagnetic energy, radiation in free space, and electromagnetic interaction of atoms. In an engaging preface, Mead tells how his approach to electromagnetic theory was inspired by his interaction with Richard Feynman. Carver A. Mead is the Gordon and Betty Moore Professor of Engineering and Applied Science, Emeritus, at the California Institute of Technology. He won the 1999 Lemelson-MIT Prize for Invention and Innovation.
Dynamics, stability, and control of maglev systems
NASA Astrophysics Data System (ADS)
Cai, Y.; Chen, S. S.; Rote, D. M.; Coffey, H. T.
The dynamic response of maglev systems is important in several respects: Safety and ride quality, guideway design, and system costs. The dynamic response of vehicles is the key element in the determination of ride quality, and vehicle stability is one of the important elements relative to safety. To design a proper guideway that provides acceptable ride quality in the stable region, the vehicle dynamics must be understood. The trade-off between guideway smoothness and the levitation and control systems must be considered if maglev systems are to be economically feasible. This paper is a summary of our previous work on dynamics, stability, and control of maglev systems. First of all, the importance of dynamics of vehicle/guideway of maglev systems is discussed. Emphasis is placed on the modeling vehicle/guideway interactions of maglev systems with a multicar, or multiload vehicle traversing on a single or double-span flexible guideway. Coupled effects of vehicle/guideway interactions in wide range of vehicle speeds with various vehicle and guideway parameters for maglev systems are investigated. Secondly, the alternative control designs of maglev vehicle suspension systems are investigated in this study to achieve safe, stable operation and acceptable ride comfort requires some form of vehicle motion control. Active and semi-active control law designs are introduced into primary and secondary suspensions of maglev vehicles. Finally, this paper discusses the stability of maglev systems based on experimental data, scoping calculations, and simple mathematical models. Divergence and flutter are obtained for coupled vibration of a three-degree-of-freedom maglev vehicle on a guideway consisting of double L-shaped aluminum segments. The theory and analysis developed in this study provides basic stability characteristics and identifies future research needs for maglev systems.
Issues Associated with a Hypersonic Maglev Sled
NASA Technical Reports Server (NTRS)
Haney, Joseph W.; Lenzo, J.
1996-01-01
Magnetic levitation has been explored for application from motors to transportation. All of these applications have been at velocities where the physics of the air or operating fluids are fairly well known. Application of Maglev to hypersonic velocities (Mach greater than 5) presents many opportunities, but also issues that require understanding and resolution. Use of Maglev to upgrade the High Speed Test Track at Holloman Air Force Base in Alamogordo New Mexico is an actual hypersonic application that provides the opportunity to improve test capabilities. However, there are several design issues that require investigation. This paper presents an overview of the application of Maglev to the test track and the issues associated with developing a hypersonic Maglev sled. The focus of this paper is to address the issues with the Maglev sled design, rather than the issues with the development of superconducting magnets of the sled system.
U. S. Maglev finally lifts off
Carlson, L.
1991-01-01
In the largest allocation of U.S. maglev funds to date, four contracts totalling $8.6 million to develop potential concepts for a maglev system in the U.S. were awarded on the last day of October. With the $4.3 million in contracts awarded in late August as a result of a BAA, this brings the total monies awarded thus far by the National Maglev Initiative to $12.9 million. The long-awaited maglev concept contracts will fund four industrial teams, each examining a different maglev concept. In this paper, each of the 11-month concept studies examines such issues as the vehicle, guideway, levitation, suspension, propulsion, braking and control, and integrate them into a complete transportation system. Each study also assesses technical feasibility, performance, capital, operating and maintenance costs for a system that would be available sometime around the turn of the century.
Dynamic suspension modeling of an eddy-current device: An application to Maglev
NASA Astrophysics Data System (ADS)
Paudel, Nirmal
When a magnetic source is simultaneously oscillated and translationally moved above a linear conductive passive guideway such as aluminum, eddy-currents are induced that give rise to a time-varying opposing field in the air-gap. This time-varying opposing field interacts with the source field, creating simultaneously suspension, propulsion or braking and lateral forces that are required for a Maglev system. In this thesis, a two-dimensional (2-D) analytic based steady-state eddy-current model has been derived for the case when an arbitrary magnetic source is oscillated and moved in two directions above a conductive guideway using a spatial Fourier transform technique. The problem is formulated using both the magnetic vector potential, A, and scalar potential, o.Using this novel A-o approach the magnetic source needs to be incorporated only into the boundary conditions of the guideway and only the magnitude of the source field along the guideway surface is required in order to compute the forces and power loss. The performance of this analytic based steady-state eddy-current model has been validated by comparing it with a 2-D finite-element model. The magnetic source used for the validation is a radially magnetized Halbach rotor, called an electrodynamic wheel (EDW). The 2-D analytic based transient eddy-current force and power loss equations are derived for the case when an arbitrary magnetic source is moving and oscillating above a conductive guideway. These general equations for force and power loss are derived using a spatial Fourier transform and temporal Laplace transform technique. The derived equations are capable of accounting for step changes in the input parameters, in addition to arbitrary continuous changes in the input conditions. The equations have been validated for both step changes as well as continuous changes in the input conditions using a 2-D transient finite-element model. The dynamics of an EDW Maglev is investigated by using both steady
A National MagLev Transportation System
NASA Technical Reports Server (NTRS)
Wright, Michael R.
2003-01-01
The case for a national high-speed magnetic-levitation (MagLev) transportation system is presented. Focus is on current issues facing the country, such as national security, the economy, transportation, technology, and the environment. NASA s research into MagLev technology for launch assist is also highlighted. Further, current socio-cultural norms regarding motor-vehicle-based transportation systems are questioned in light of the problems currently facing the U.S. The multidisciplinary benefits of a long-distance MagLev system support the idea that such a system would be an important element of a truly multimodal U.S. transportation infrastructure.
A review of dynamic stability of repulsive-force maglev suspension systems
Cai, Y.; Rote, D.M.
1998-07-01
Vehicle dynamics and the need to satisfy ride quality requirements have long been recognized as crucial to the commercial success of passenger-carrying transportation systems. Design concepts for maglev systems are no exception. Early maglev investigators and designers were well aware of the importance of ride quality and took care to ensure that their designs would meet acceptable ride quality standards. In contrast, the dynamic stability of electrodynamic suspension (EDS) systems, which has obvious implications for system safety and cost as well as for ride quality, has not received nearly as much attention. Because of the well-known under-damped nature of EDS suspension systems and the observation of instabilities in laboratory-scale model systems, it is prudent to develop a better understanding of vehicle stability characteristics. The work reported in this was undertaken with the intention of summarizing information that has been accumulated worldwide and that is relevant to dynamic stability of repulsive-force maglev suspension systems, assimilating that information, and gaining an understanding of the factors that influence that stability. Included in the paper is a discussion and comparison of results acquired from some representative tests of large-scale vehicles on linear test tracks, together with analytical and laboratory-scale investigations of stability and dynamics of EDS systems. This paper will also summarize the R and D activities at Argonne National Laboratory (ANL) since 1991 to study the nature of the forces that are operative in an EDS system and the dynamic stability of such systems.
Research on the Filtering Algorithm in Speed and Position Detection of Maglev Trains
Dai, Chunhui; Long, Zhiqiang; Xie, Yunde; Xue, Song
2011-01-01
This paper introduces in brief the traction system of a permanent magnet electrodynamic suspension (EDS) train. The synchronous traction mode based on long stators and track cable is described. A speed and position detection system is recommended. It is installed on board and is used as the feedback end. Restricted by the maglev train’s structure, the permanent magnet electrodynamic suspension (EDS) train uses the non-contact method to detect its position. Because of the shake and the track joints, the position signal sent by the position sensor is always aberrant and noisy. To solve this problem, a linear discrete track-differentiator filtering algorithm is proposed. The filtering characters of the track-differentiator (TD) and track-differentiator group are analyzed. The four series of TD are used in the signal processing unit. The result shows that the track-differentiator could have a good effect and make the traction system run normally. PMID:22164012
Aerodynamics of magnetic levitation (MAGLEV) trains
NASA Technical Reports Server (NTRS)
Schetz, Joseph A.; Marchman, James F., III
1996-01-01
High-speed (500 kph) trains using magnetic forces for levitation, propulsion and control offer many advantages for the nation and a good opportunity for the aerospace community to apply 'high tech' methods to the domestic sector. One area of many that will need advanced research is the aerodynamics of such MAGLEV (Magnetic Levitation) vehicles. There are important issues with regard to wind tunnel testing and the application of CFD to these devices. This talk will deal with the aerodynamic design of MAGLEV vehicles with emphasis on wind tunnel testing. The moving track facility designed and constructed in the 6 ft. Stability Wind Tunnel at Virginia Tech will be described. Test results for a variety of MAGLEV vehicle configurations will be presented. The last topic to be discussed is a Multi-disciplinary Design approach that is being applied to MAGLEV vehicle configuration design including aerodynamics, structures, manufacturability and life-cycle cost.
NASA Technical Reports Server (NTRS)
Stern, David P.
1990-01-01
The present one-dimensional model analysis of substorm electrodynamics proceeds from the standard scenario in which the plasma sheet collapses into a neutral sheet, and magnetic merging occurs between the two tail lobes; plasma flows into the neutral sheet from the lobes and the sides, undergoing acceleration in the dawn-dusk direction. The process is modified by the tendency of the accelerated plasma to unbalance charge neutrality, leading to an exchange of electrons with the ionosphere in order to maintain neutrality. The cross-tail current is weakened by the diversion: this reduces the adjacent lobe-field intensity, but without notable effects apart from a slight expansion of the tail boundary.
Implementation of cargo MagLev in the United States
Rose, Chris R; Peterson, Dean E; Leung, Eddie M
2008-01-01
Numerous studies have been completed in the United States, but no commercial MagLev systems have been deployed. Outside the U.S., MagLev continues to attract funding for research, development and implementation. A brief review of recent global developments in MagLev technology is given followed by the status of MagLev in the U.S. The paper compares the cost of existing MagLev systems with other modes of transport, notes that the near-term focus of MagLev development in the U.S. should be for cargo, and suggests that future MagLev systems should be for very high speed cargo. The Los Angeles to Port of Los Angeles corridor is suggested as a first site for implementation. The benefits of MagLev are described along with suggestions on how to obtain funding.
NASA Astrophysics Data System (ADS)
Proise, M.
1994-05-01
Grumman, under contract to the Army Corps of Engineers, completed a System Concept Definition (SCD) study to design a high-speed 134 m/s (300 m.p.h.) magnetically levitated (Maglev) transportation system. The primary development goals were to design a Maglev that is safe, reliable, environmentally acceptable, and low-cost. The cost issue was a predominant one, since previous studies have shown that an economically viable Maglev system (one that is attractive to investors for future models of passenger and/or freight transportation) requires a cost that is about $12.4 M/km ($20 Million per mile). The design is based on the electromagnetic suspension (EMS) system using superconducting iron-core magnets mounted along both sides of the vehicle. The EMS system has several advantages compared to the electrodynamic suspension (EDS) Maglev systems such as low stray magnetic fields in the passenger cabin and the surrounding areas, uniform load distribution along the full length of the vehicle, and small pole pitch for smoother propulsion and ride comfort. It is also levitated at all speeds and incorporates a wrap-around design of safer operation. The Grumman design has all the advantages of an EMS system identified above, while eliminating (or significantly improving) drawbacks associated with normal magnet powered EMS systems. Improvements include larger gap clearance, lighter weight, lower number of control servos, and higher off line switching speeds. The design also incorporates vehicle tilt (plus or minus 9 deg) for higher coordinated turn and turn out speed capability.
NASA Technical Reports Server (NTRS)
Proise, M.
1994-01-01
Grumman, under contract to the Army Corps of Engineers, completed a System Concept Definition (SCD) study to design a high-speed 134 m/s (300 m.p.h.) magnetically levitated (Maglev) transportation system. The primary development goals were to design a Maglev that is safe, reliable, environmentally acceptable, and low-cost. The cost issue was a predominant one, since previous studies have shown that an economically viable Maglev system (one that is attractive to investors for future models of passenger and/or freight transportation) requires a cost that is about $12.4 M/km ($20 Million per mile). The design is based on the electromagnetic suspension (EMS) system using superconducting iron-core magnets mounted along both sides of the vehicle. The EMS system has several advantages compared to the electrodynamic suspension (EDS) Maglev systems such as low stray magnetic fields in the passenger cabin and the surrounding areas, uniform load distribution along the full length of the vehicle, and small pole pitch for smoother propulsion and ride comfort. It is also levitated at all speeds and incorporates a wrap-around design of safer operation. The Grumman design has all the advantages of an EMS system identified above, while eliminating (or significantly improving) drawbacks associated with normal magnet powered EMS systems. Improvements include larger gap clearance, lighter weight, lower number of control servos, and higher off line switching speeds. The design also incorporates vehicle tilt (plus or minus 9 deg) for higher coordinated turn and turn out speed capability.
Maglev guideway cost and construction schedule assessment
Plotkin, D.; Kim, S.
1997-05-01
A summary of construction cost and scheduling information is presented for four maglev guideway designs on an example route from Baltimore, MD to Newark, NJ. This work results from the National Maglev Initiative (NMI), a government-industry effort from 1989 to 1994. The system design concepts used as a basis for developing cost and construction scheduling information, were submitted by four industry consortia solely for this analysis, and represent their own unpublished designs. The detailed cost and construction schedule analyses cover the main guideway only. A summary estimate was made for stations, power distribution systems, maintenance facilities, and other types of infrastructure. The results of the analyses indicate a number of design aspects which must receive further consideration by future designers. These aspects will affect the practical and economic construction and long-term maintenance of a high-speed maglev guideway.
Dynamics and controls in maglev systems
Cai, Y.; Chen, S.S.; Rote, D.M.
1992-09-01
The dynamic response of magnetically levitated (maglev) ground transportation systems has important consequences for safety and ride quality, guideway design, and system costs. Ride quality is determined by vehicle response and by environmental factors such as humidity and noise. The dynamic response of the vehicles is the key element in determining ride quality, and vehicle stability is an important safety-related element. To design a proper guideway that provides acceptable ride quality in the stable region, vehicle dynamics must be understood. Furthermore the trade-off between guideway smoothness and the levitation and control systems must be considered if maglev systems are to be economically feasible. The link between the guideway and the other maglev components is vehicle dynamics. For a commercial maglev system, vehicle dynamics must be analyzed and tested in detail. In this study, the role of dynamics and controls in maglev vehicle/guideway interactions is discussed, and the literature on modeling the dynamic interactions of vehicle/guideway and suspension controls for ground vehicles is reviewed. Particular emphasis is placed on modeling vehicle/guideway interactions and response characteristics of maglev systems for a multicar, multiload vehicle traveling on a single- or doublespan flexible guideway, including coupling effects of vehicle/guideway, comparison of concentrated and distributed loads, and ride comfort. Different control-law designs are introduced into vehicle suspensions when a simple two-degree-of-freedom vehicle model is applied. Active and semiactive control designs for primary and secondary suspensions do improve the response of vehicle and provide acceptable ride comfort. Finally, future research associated with dynamics and controls of vehicle/guideway systems is identified.
Workshop on technology issues of superconducting Maglev transportation systems
Wegrzyn, J.E. ); Shaw, D.T. )
1991-09-27
There exists a critical need in the United States to improve its ground transportation system. One suggested system that offers many advantages over the current transportation infrastructure is Maglev. Maglev represents the latest evolution in very high and speed ground transportation, where vehicles are magnetically levitated, guided, and propelled over elevated guideways at speeds of 300 miles per hour. Maglev is not a new concept but is, however, receiving renewed interest. The objective of this workshop was to further promote these interest by bringing together a small group of specialists in Maglev technology to discuss Maglev research needs and to identify key research issues to the development of a successful Maglev system. The workshop was organized into four sessions based on the following technical areas: Materials, Testing, and Shielding; Magnet Design and Cryogenic Systems; Propulsion and Levitation Systems; and, System Control and Integration.
Present status of computational tools for Maglev development
NASA Astrophysics Data System (ADS)
Wang, Z.; Chen, S. S.; Rote, D. M.
1991-10-01
High-speed vehicles that employ magnetic levitation (maglev) have received great attention worldwide as a means of relieving both highway and air-traffic congestion. At this time, Japan and Germany are leading the development of maglev. After fifteen years of inactivity that is attributed to technical policy decisions, the Federal government of the United States has reconsidered the possibility of using maglev in the United States. The National Maglev Initiative (NMI) was established in May 1990 to assess the potential of maglev in the United States. One of the tasks of the NMI, which is also the objective of this report, is to determine the status of existing computer software that can be applied to maglev-related problems. The computational problems involved in maglev assessment, research, and development can be classified into two categories: electromagnetic and mechanical. Because most maglev problems are complicated and difficult to solve analytically, proper numerical methods are needed to find solutions. To determine the status of maglev-related software, developers and users of computer codes were surveyed. The results of the survey are described in this report.
Present status of computational tools for maglev development
Wang, Z.; Chen, S.S.; Rote, D.M.
1991-10-01
High-speed vehicles that employ magnetic levitation (maglev) have received great attention worldwide as a means of relieving both highway and air-traffic congestion. At this time, Japan and Germany are leading the development of maglev. After fifteen years of inactivity that is attributed to technical policy decisions, the federal government of the United States has reconsidered the possibility of using maglev in the United States. The National Maglev Initiative (NMI) was established in May 1990 to assess the potential of maglev in the United States. One of the tasks of the NMI, which is also the objective of this report, is to determine the status of existing computer software that can be applied to maglev-related problems. The computational problems involved in maglev assessment, research, and development can be classified into two categories: electromagnetic and mechanical. Because most maglev problems are complicated and difficult to solve analytically, proper numerical methods are needed to find solutions. To determine the status of maglev-related software, developers and users of computer codes were surveyed. The results of the survey are described in this report. 25 refs.
Ribani, P.L.; Urbano, N.
2000-01-01
Two figure-eight-shaped coils for electrodynamic suspension (EDS) magnetic levitation (MAGLEV) systems without cross-connection are proposed and analyzed. The guideway coils are positioned under the MAGLEV vehicle; they are parallel to the horizontal plane. The interaction of a magnetic module on the vehicle, composed of three or four superconducting (SC) coils, with a guideway module, comprised of two figure-eight coils, is studied by means of the dynamic circuit theory. The currents in the SC coils are supposed to be constant in time while they move as a rigid body, with a constant velocity. Some results are presented and compared with those for a standard side-wall cross-connected system.
A Hands-On Approach to Maglev for Gifted Students.
ERIC Educational Resources Information Center
Budd, Raymond T.
2003-01-01
This article discusses how Magnetic Levitation (Maglev) can be taught to gifted students in grades 4-9 using hands-on activities that align to the National Science Standards. Principles of magnetic levitation, advantages of magnetic levitation, construction of a Maglev project, testing and evaluation of vehicles, and presentation of the unit are…
Maglev technology. (Latest citations from the INSPEC database). Published Search
1996-02-01
The bibliography contains citations concerning magnetic levitation (Maglev) technology. The citations discuss the use of permanent and electromagnets, superconducting magnets, and superconductors in the design of transportation and energy saving systems. Future markets for Maglev technology are also examined.(Contains 50-250 citations and includes a subject term index and title list.) (Copyright NERAC, Inc. 1995)
Maglev technology. (Latest citations from the INSPEC database). Published Search
1996-11-01
The bibliography contains citations concerning magnetic levitation (Maglev) technology. The citations discuss the use of permanent and electromagnets, superconducting magnets, and superconductors in the design of transportation and energy saving systems. Future markets for Maglev technology are also examined. (Contains 50-250 citations and includes a subject term index and title list.) (Copyright NERAC, Inc. 1995)
Maglev technology. (Latest citations from the INSPEC database). Published Search
Not Available
1994-04-01
The bibliography contains citations concerning magnetic levitation (Maglev) technology. The citations discuss the use of permanent and electro- magnets, superconducting magnets, and superconductors in the design of transportation and energy saving systems. Future markets for Maglev technology are also examined. (Contains a minimum of 123 citations and includes a subject term index and title list.)
Maglev technology. (Latest citations from the INSPEC database). Published Search
1998-02-01
The bibliography contains citations concerning magnetic levitation (Maglev) technology. The citations discuss the use of permanent and electromagnets, superconducting magnets, and superconductors in the design of transportation and energy saving systems. Future markets for Maglev technology are also examined. (Contains 50-250 citations and includes a subject term index and title list.) (Copyright NERAC, Inc. 1995)
Maglev technology. (Latest citations from the INSPEC database). Published Search
1995-02-01
The bibliography contains citations concerning magnetic levitation (Maglev) technology. The citations discuss the use of permanent and electro-magnets, superconducting magnets, and superconductors in the design of transportation and energy saving systems. Future markets for Maglev technology are also examined. (Contains a minimum of 142 citations and includes a subject term index and title list.)
Simulation of stochastic vibration of maglev track inspection vehicle
NASA Astrophysics Data System (ADS)
Liu, Xingchu; Guan, Xiqiang; Zhang, Jianwu
2007-05-01
The stochastic vibration of a maglev track inspection vehicle is the main factor that has direct influence on the accuracy of geometrical measurements of the maglev tracks on board whenever the inspection vehicle is operated at a certain speed. Based upon the principle of motions of the specified vehicle, a vibration model of 5 dof for the maglev track inspection vehicle is proposed and a numerical example is made for the analysis of dynamic responses of the vehicle in stochastic excitation of the maglev track. Effects of vibrations of the vehicle on the accuracy of measuring displacement by laser triangle method are examined. Simulation results of lateral, vertical, roll, pitch, and yaw vibrations for the maglev track inspection vehicle equipped with the measuring system of high precision are provided for the design of the similar vehicles.
Potential impact of high temperature superconductors on MAGLEV transportation
NASA Astrophysics Data System (ADS)
Hull, J. R.
1992-02-01
This report describes the potential impact that high-temperature superconductors (HTS's) may have on transportation by magnetically levitated vehicles. It is not intended as a planning document, but rather as an overview of potential HTS applications to magnetic-levitation (maglev) transportation. The present maglev program in the United States is summarized, and the present status of development of HTS's is described. Areas identified for possible impact on maglev technology are: (1) liquid-nitrogen-cooled levitation magnets; (2) magnetic-field shielding of the passenger compartment; (3) superconducting magnetic energy storage for wayside power; (4) superconducting bearings for flywheel energy storage for wayside power; (5) downleads to continuously powered liquid-helium-cooled levitation magnets; and (6) liquid-hydrogen-cooled levitation magnets and linear motor propulsion windings. Major technical issues that remain to be resolved for the use of HTS's in maglev applications include thermal magnetic stability, mechanical properties, and critical current density at liquid-nitrogen temperatures.
Potential impact of high temperature superconductors on maglev transportation
Hull, J.R.
1992-02-01
This report describes the potential impact that high-temperature superconductors (HTSs) may have on transportation by magnetically levitated vehicles. It is not intended as a planning document, but rather as an overview of potential HTS applications to magnetic-levitation (maglev) transportation. The present maglev program in the United States is summarized, and the present status of development of HTSs is described. Areas identified for possible impact on maglev technology are (1) liquid-nitrogen-cooled levitation magnets, (2) magnetic-field shielding of the passenger compartment, (3) superconducting magnetic energy storage for wayside power, (4) superconducting bearings for flywheel energy storage for wayside power, (5) downleads to continuously powered liquid-helium-cooled levitation magnets, and (6) liquid-hydrogen-cooled levitation magnets and linear motor propulsion windings. Major technical issues that remain to be resolved for the use of HTSs in maglev applications include thermal magnetic stability, mechanical properties, and critical current density at liquid-nitrogen temperatures.
Market and energy demand analysis of a US maglev system
Vyas, A.D.; Rote, D.M.
1993-01-01
High-speed magnetically levitated (maglev) vehicles can provide an alternative mode of transportation for intercity travel, particularly for short- and medium-distance trips between 100 to 600 mi (160 and 960 km). The patterns of growth and the underlying factors affecting that growth In the year 2010 are evaluated to determine the magnitude of US Intercity travel that would become the basis for maglev demand. A methodology that is sensitive to the travelers' socioeconomic attributes was developed to Forecast intercity travel. Travel between 78 major metropolitan areas by air and highway modes is projected, and 12 high-density travel corridors are Identified and selected. The potential for a maglev system to substitute for part or that travel is calculated by using a model that estimates the extent of diversion from highway and air to maglev. Energy demand is estimated on the basis of energy usage during acceleration and cruise phases for each corridor and corridor connections.
Market and energy demand analysis of a US maglev system
Vyas, A.D.; Rote, D.M.
1993-06-01
High-speed magnetically levitated (maglev) vehicles can provide an alternative mode of transportation for intercity travel, particularly for short- and medium-distance trips between 100 to 600 mi (160 and 960 km). The patterns of growth and the underlying factors affecting that growth In the year 2010 are evaluated to determine the magnitude of US Intercity travel that would become the basis for maglev demand. A methodology that is sensitive to the travelers` socioeconomic attributes was developed to Forecast intercity travel. Travel between 78 major metropolitan areas by air and highway modes is projected, and 12 high-density travel corridors are Identified and selected. The potential for a maglev system to substitute for part or that travel is calculated by using a model that estimates the extent of diversion from highway and air to maglev. Energy demand is estimated on the basis of energy usage during acceleration and cruise phases for each corridor and corridor connections.
Preliminary design for a maglev development facility
Coffey, H.T.; He, J.L.; Chang, S.L.; Bouillard, J.X.; Chen, S.S.; Cai, Y.; Hoppie, L.O.; Lottes, S.A.; Rote, D.M. ); Zhang, Z.Y. ); Myers, G.; Cvercko, A. ); Williams, J.R. )
1992-04-01
A preliminary design was made of a national user facility for evaluating magnetic-levitation (maglev) technologies in sizes intermediate between laboratory experiments and full-scale systems. A technical advisory committee was established and a conference was held to obtain advice on the potential requirements of operational systems and how the facility might best be configured to test these requirements. The effort included studies of multiple concepts for levitating, guiding, and propelling maglev vehicles, as well as the controls, communications, and data-acquisition and -reduction equipment that would be required in operating the facility. Preliminary designs for versatile, dual 2-MVA power supplies capable of powering attractive or repulsive systems were developed. Facility site requirements were identified. Test vehicles would be about 7.4 m (25 ft) long, would weigh form 3 to 7 metric tons, and would operate at speeds up to 67 m/s (150 mph) on a 3.3-km (2.05-mi) elevated guideway. The facility would utilize modular vehicles and guideways, permitting the substitution of levitation, propulsion, and guideway components of different designs and materials for evaluation. The vehicle would provide a test cell in which individual suspension or propulsion components or subsystems could be tested under realistic conditions. The system would allow economical evaluation of integrated systems under varying weather conditions and in realistic geometries.
Structure of Aristotelian electrodynamics
NASA Astrophysics Data System (ADS)
Jacobson, Ted
2015-07-01
Aristotelian electrodynamics (AE) describes the regime of a plasma with a very strong electric field that is not shorted out, with the charge current determined completely by pair production and the balance of the Lorentz 4-force against the curvature radiation reaction. Here it is shown how the principal null directions and associated eigenvalues of the field tensor govern AE, and how force-free electrodynamics arises smoothly from AE when the eigenvalues (and therefore the electric field in some frame) vanish. A criterion for validity of AE and force-free electrodynamics is proposed in terms of a pair of "field curvature scalars" formed from the first derivative of the principal null directions.
First quantized electrodynamics
Bennett, A.F.
2014-06-15
The parametrized Dirac wave equation represents position and time as operators, and can be formulated for many particles. It thus provides, unlike field-theoretic Quantum Electrodynamics (QED), an elementary and unrestricted representation of electrons entangled in space or time. The parametrized formalism leads directly and without further conjecture to the Bethe–Salpeter equation for bound states. The formalism also yields the Uehling shift of the hydrogenic spectrum, the anomalous magnetic moment of the electron to leading order in the fine structure constant, the Lamb shift and the axial anomaly of QED. -- Highlights: •First-quantized electrodynamics of the parametrized Dirac equation is developed. •Unrestricted entanglement in time is made explicit. •Bethe and Salpeter’s equation for relativistic bound states is derived without further conjecture. •One-loop scattering corrections and the axial anomaly are derived using a partial summation. •Wide utility of semi-classical Quantum Electrodynamics is argued.
Gyro-effect stabilizes unstable permanent maglev centrifugal pump.
Qian, Kun-Xi
2007-03-01
According to Earnshaw's Theorem (1839), the passive maglev cannot achieve stable equilibrium and thus an extra coil is needed to make the rotor electrically levitated in a heart pump. The author had developed a permanent maglev centrifugal pump utilizing only passive magnetic bearings, to keep the advantages but to avoid the disadvantages of the electric maglev pumps. The equilibrium stability was achieved by use of so-called "gyro-effect": a rotating body with certain high speed can maintain its rotation stably. This pump consisted of a rotor (driven magnets and an impeller), and a stator with motor coil and pump housing. Two passive magnetic bearings between rotor and stator were devised to counteract the attractive force between the motor coil iron core and the rotor driven magnets. Bench testing with saline demonstrated a levitated rotor under preconditions of higher than 3,250 rpm rotation and more than 1 l/min pumping flow. Rotor levitation was demonstrated by 4 Hall sensors on the stator, with evidence of reduced maximal eccentric distance from 0.15 mm to 0.07 mm. The maximal rotor vibration amplitude was 0.06 mm in a gap of 0.15 mm between rotor and stator. It concluded that Gyro-effect can help passive maglev bearings to achieve stabilization of permanent maglev pump; and that high flow rate indicates good hydraulic property of the pump, which helps also the stability of passive maglev pump.
Fault tolerant computer control for a Maglev transportation system
NASA Technical Reports Server (NTRS)
Lala, Jaynarayan H.; Nagle, Gail A.; Anagnostopoulos, George
1994-01-01
Magnetically levitated (Maglev) vehicles operating on dedicated guideways at speeds of 500 km/hr are an emerging transportation alternative to short-haul air and high-speed rail. They have the potential to offer a service significantly more dependable than air and with less operating cost than both air and high-speed rail. Maglev transportation derives these benefits by using magnetic forces to suspend a vehicle 8 to 200 mm above the guideway. Magnetic forces are also used for propulsion and guidance. The combination of high speed, short headways, stringent ride quality requirements, and a distributed offboard propulsion system necessitates high levels of automation for the Maglev control and operation. Very high levels of safety and availability will be required for the Maglev control system. This paper describes the mission scenario, functional requirements, and dependability and performance requirements of the Maglev command, control, and communications system. A distributed hierarchical architecture consisting of vehicle on-board computers, wayside zone computers, a central computer facility, and communication links between these entities was synthesized to meet the functional and dependability requirements on the maglev. Two variations of the basic architecture are described: the Smart Vehicle Architecture (SVA) and the Zone Control Architecture (ZCA). Preliminary dependability modeling results are also presented.
Electrodynamic thermogravimetric analyzer
NASA Astrophysics Data System (ADS)
Spjut, R. Erik; Bar-Ziv, Ezra; Sarofim, Adel F.; Longwell, John P.
1986-08-01
The design and operation of a new device for studying single-aerosol-particle kinetics at elevated temperatures, the electrodynamic thermogravimetric analyzer (EDTGA), was examined theoretically and experimentally. The completed device consists of an electrodynamic balance modified to permit particle heating by a CO2 laser, temperature measurement by a three-color infrared-pyrometry system, and continuous weighing by a position-control system. In this paper, the position-control, particle-weight-measurement, heating, and temperature-measurement systems are described and their limitations examined.
Electrodynamics, wind and temperature
NASA Technical Reports Server (NTRS)
Schmidlin, F. J.
1988-01-01
This RTOP provides for correlative meteorological wind and temperature measurements with atmospheric electrodynamic measurements. Meteorological rocketsondes were launched as part of a number of electrodynamic investigations in Alaska, Norway, Peru, Sweden, and at the Wallops Flight Facility, Wallops Island, Virginia. Measurements obtained as part of the MAC/Epsilon campaign during October 1987 from Andoya, Norway, were in conjunction with electric field, ion mobility, conductivity, and energy deposition studies. The measurements obtained between 30 and 90 km are to evaluate and correlate changes in the atmospheric electrical structure caused by the neutral wind and temperature, or changes in the neutral atmosphere resulting from electrical anomalies.
Electrodynamics panel presentation
NASA Technical Reports Server (NTRS)
Mccoy, J.
1986-01-01
The Plasma Motor Generator (PMG) concept is explained in detail. The PMG tether systems being used to calculate the estimated performance data is described. The voltage drops and current contact geometries involved in the operation of an electrodynamic tether are displayed illustrating the comparative behavior of hollow cathodes, electron guns, and passive collectors for current coupling into the ionosphere. The basic PMG design involving the massive tether cable with little or no satellite mass at the far end(s) are also described. The Jupiter mission and its use of electrodynamic tethers are given. The need for demonstration experiments is stressed.
Maglev Facility for Simulating Variable Gravity
NASA Technical Reports Server (NTRS)
Liu, Yuanming; Strayer, Donald M.; Israelsson, Ulf E.
2010-01-01
An improved magnetic levitation apparatus ("Maglev Facility") has been built for use in experiments in which there are requirements to impose variable gravity (including zero gravity) in order to assess the effects of gravity or the absence thereof on physical and physiological processes. The apparatus is expected to be especially useful for experiments on the effects of gravity on convection, boiling, and heat transfer in fluids and for experiments on mice to gain understanding of bone loss induced in human astronauts by prolonged exposure to reduced gravity in space flight. The maglev principle employed by the apparatus is well established. Diamagnetic cryogenic fluids such as liquid helium have been magnetically levitated for studying their phase transitions and critical behaviors. Biological entities consist mostly of diamagnetic molecules (e.g., water molecules) and thus can be levitated by use of sufficiently strong magnetic fields having sufficiently strong vertical gradients. The heart of the present maglev apparatus is a vertically oriented superconducting solenoid electromagnet (see figure) that generates a static magnetic field of about 16 T with a vertical gradient sufficient for levitation of water in normal Earth gravity. The electromagnet is enclosed in a Dewar flask having a volume of 100 L that contains liquid helium to maintain superconductivity. The Dewar flask features a 66-mm-diameter warm bore, lying within the bore of the magnet, wherein experiments can be performed at room temperature. The warm bore is accessible from its top and bottom ends. The superconducting electromagnet is run in the persistent mode, in which the supercurrent and the magnetic field can be maintained for weeks with little decay, making this apparatus extremely cost and energy efficient to operate. In addition to water, this apparatus can levitate several common fluids: liquid hydrogen, liquid oxygen, methane, ammonia, sodium, and lithium, all of which are useful
Causality in Classical Electrodynamics
ERIC Educational Resources Information Center
Savage, Craig
2012-01-01
Causality in electrodynamics is a subject of some confusion, especially regarding the application of Faraday's law and the Ampere-Maxwell law. This has led to the suggestion that we should not teach students that electric and magnetic fields can cause each other, but rather focus on charges and currents as the causal agents. In this paper I argue…
Quantum Electrodynamics: Theory
Lincoln, Don
2016-03-30
The Standard Model of particle physics is composed of several theories that are added together. The most precise component theory is the theory of quantum electrodynamics or QED. In this video, Fermilab’s Dr. Don Lincoln explains how theoretical QED calculations can be done. This video links to other videos, giving the viewer a deep understanding of the process.
Quantum Electrodynamics: Theory
Lincoln, Don
2016-07-12
The Standard Model of particle physics is composed of several theories that are added together. The most precise component theory is the theory of quantum electrodynamics or QED. In this video, Fermilabâs Dr. Don Lincoln explains how theoretical QED calculations can be done. This video links to other videos, giving the viewer a deep understanding of the process.
On a modified electrodynamics.
Reiss, H R
2012-09-01
A modification of electrodynamics is proposed, motivated by previously unremarked paradoxes that can occur in the standard formulation. It is shown by specific examples that gauge transformations exist that radically alter the nature of a problem, even while maintaining the values of many measurable quantities. In one example, a system with energy conservation is transformed to a system where energy is not conserved. The second example possesses a ponderomotive potential in one gauge, but this important measurable quantity does not appear in the gauge-transformed system. A resolution of the paradoxes comes from noting that the change in total action arising from the interaction term in the Lagrangian density cannot always be neglected, contrary to the usual assumption. The problem arises from the information lost by employing an adiabatic cutoff of the field. This is not necessary. Its replacement by a requirement that the total action should not change with a gauge transformation amounts to a supplementary condition for gauge invariance that can be employed to preserve the physical character of the problem. It is shown that the adiabatic cutoff procedure can also be eliminated in the construction of quantum transition amplitudes, thus retaining consistency between the way in which asymptotic conditions are applied in electrodynamics and in quantum mechanics. The 'gauge-invariant electrodynamics' of Schwinger is shown to depend on an ansatz equivalent to the condition found here for maintenance of the ponderomotive potential in a gauge transformation. Among the altered viewpoints required by the modified electrodynamics, in addition to the rejection of the adiabatic cutoff, is the recognition that the electric and magnetic fields do not completely determine a physical problem, and that the electromagnetic potentials supply additional information that is required for completeness of electrodynamics.
National Maglev initiative: California line electric utility power system requirements
NASA Technical Reports Server (NTRS)
Save, Phil
1994-01-01
The electrical utility power system requirements were determined for a Maglev line from San Diego to San Francisco and Sacramento with a maximum capacity of 12,000 passengers an hour in each direction at a speed of 300 miles per hour, or one train every 30 seconds in each direction. Basically the Maglev line requires one 50-MVA substation every 12.5 miles. The need for new power lines to serve these substations and their voltage levels are based not only on equipment loading criteria but also on limitations due to voltage flicker and harmonics created by the Maglev system. The resulting power system requirements and their costs depend mostly on the geographical area, urban or suburban with 'strong' power systems, or mountains and rural areas with 'weak' power systems. A reliability evaluation indicated that emergency power sources, such as a 10-MW battery at each substation, were not justified if sufficient redundancy is provided in the design of the substations and the power lines serving them. With a cost of $5.6 M per mile, the power system requirements, including the 12-kV DC cables and the inverters along the Maglev line, were found to be the second largest cost component of the Maglev system, after the cost of the guideway system ($9.1 M per mile), out of a total cost of $23 M per mile.
Electrodynamics of chiral matter
NASA Astrophysics Data System (ADS)
Qiu, Zebin; Cao, Gaoqing; Huang, Xu-Guang
2017-02-01
Many-body systems with chiral fermions can exhibit novel transport phenomena that violate parity and time-reversal symmetries, such as the chiral magnetic effect, the anomalous Hall effect, and the anomalous generation of charge. Based on the Maxwell-Chern-Simons electrodynamics, we examine some electromagnetic and optical properties of such systems including the electrostatics, the magnetostatics, the propagation of electromagnetic waves, the novel optical effects, etc.
Electrodynamics of Pulsar Magnetospheres
NASA Astrophysics Data System (ADS)
Cerutti, Benoît; Beloborodov, Andrei M.
2016-12-01
We review electrodynamics of rotating magnetized neutron stars, from the early vacuum model to recent numerical experiments with plasma-filled magnetospheres. Significant progress became possible due to the development of global particle-in-cell simulations which capture particle acceleration, emission of high-energy photons, and electron-positron pair creation. The numerical experiments show from first principles how and where electric gaps form, and promise to explain the observed pulsar activity from radio waves to gamma-rays.
Accretion disk electrodynamics
NASA Technical Reports Server (NTRS)
Coroniti, F. V.
1985-01-01
Accretion disk electrodynamic phenomena are separable into two classes: (1) disks and coronas with turbulent magnetic fields; (2) disks and black holes which are connected to a large-scale external magnetic field. Turbulent fields may originate in an alpha-omega dynamo, provide anomalous viscous transport, and sustain an active corona by magnetic buoyancy. The large-scale field can extract energy and angular momentum from the disk and black hole, and be dynamically configured into a collimated relativistic jet.
Extended symmetrical classical electrodynamics.
Fedorov, A V; Kalashnikov, E G
2008-03-01
In this paper, we discuss a modification of classical electrodynamics in which "ordinary" point charges are absent. The modified equations contain additional terms describing the induced charges and currents. The densities of the induced charges and currents depend on the vector k and the vectors of the electromagnetic field, E and B . It is shown that the vectors E and B can be defined in terms of two four-potentials and the components of k are the components of a four-tensor of the third rank. The Lagrangian of the modified electrodynamics is defined. The conditions are derived at which only one four-potential determines the behavior of the electromagnetic field. It is also shown that static modified electrodynamics can describe the electromagnetic field in the inner region of an electric monopole. In the outer region of the electric monopole the electric field is governed by the Maxwell equations. It follows from boundary conditions at the interface between the inner and outer regions of the monopole that the vector k has a discrete spectrum. The electric and magnetic fields, energy, and angular momentum of the monopole are found for different eigenvalues of k .
Comparison of high-speed rail and maglev system costs
Rote, D.M.
1998-07-01
This paper compares the two modes of transportation, and notes important similarities and differences in the technologies and in how they can be implemented to their best advantage. Problems with making fair comparisons of the costs and benefits are discussed and cost breakdowns based on data reported in the literature are presented and discussed in detail. Cost data from proposed and actual construction projects around the world are summarized and discussed. Results from the National Maglev Initiative and the recently-published Commercial Feasibility Study are included in the discussion. Finally, estimates will be given of the expected cost differences between HSR and maglev systems implemented under simple and complex terrain conditions. The extent to which the added benefits of maglev technology offset the added costs is examined.
Vehicle/guideway interaction and ride comfort in maglev systems
Cai, Y.; Chen, S.S.; Rote, D.M.; Coffey, H.T.
1993-10-01
The importance of vehicle/guideway dynamics in maglev systems is discussed. The particular interest associated with modeling vehicle guide-way interactions and explaining response characteristics of maglev systems for a multicar, multiload vehicle traversing on a single- or double-span flexible guideway are considered, with an emphasis on vehicle/guideway coupling effects, comparison of concentrated and distributed loads, and ride comfort. Coupled effects of vehicle/guideway interactions over a wide range of vehicle speeds with various vehicle and guideway parameters are investigated, and appropriate critical vehicle speeds or crossing frequencies are identified.
Robust levitation control for maglev systems with guaranteed bounded airgap.
Xu, Jinquan; Chen, Ye-Hwa; Guo, Hong
2015-11-01
The robust control design problem for the levitation control of a nonlinear uncertain maglev system is considered. The uncertainty is (possibly) fast time-varying. The system has magnitude limitation on the airgap between the suspended chassis and the guideway in order to prevent undesirable contact. Furthermore, the (global) matching condition is not satisfied. After a three-step state transformation, a robust control scheme for the maglev vehicle is proposed, which is able to guarantee the uniform boundedness and uniform ultimate boundedness of the system, regardless of the uncertainty. The magnitude limitation of the airgap is guaranteed, regardless of the uncertainty.
Semi-classical Electrodynamics
NASA Astrophysics Data System (ADS)
Lestone, John
2016-03-01
Quantum electrodynamics is complex and its associated mathematics can appear overwhelming for those not trained in this field. We describe semi-classical approaches that can be used to obtain a more intuitive physical feel for several QED processes including electro-statics, Compton scattering, pair annihilation, the anomalous magnetic moment, and the Lamb shift, that could be taught easily to undergraduate students. Any physicist who brings their laptop to the talk will be able to build spread sheets in less than 10 minutes to calculate g/2 =1.001160 and a Lamb shift of 1057 MHz.
Characterizing electrodynamic shakers
Smallwood, D.O.
1996-12-31
An electrodynamic shaker is modeled as a mixed electrical/mechanical system with an experimentally derived two port network characterization. The model characterizes the shaker in a manner that the performance of the shaker with a mounted load (test item and fixture) can be predicted. The characterization depends on the measurements of shaker input voltage and current, and on the acceleration of the shaker armature with several mounted loads. The force into the load is also required, and can be measured directly or inferred from the load apparent mass.
A mini axial and a permanent maglev radial heart pump.
Qian, Kun-Xi; Ru, Wei-Min; Wang, Hao; Jing, Teng
2007-05-31
The implantability and durability have been for decades the focus of artificial heart R&D. A mini axial and a maglev radial pump have been developed to meet with such requirements.The mini axial pump weighing 27g (incl.5g rotor) has an outer diameter of 21mm and a length of 10mm in its largest point, but can produce a maximal blood flow of 6l/min with 50mmHg pressure increase. Therefore, it is suitable for the patients of 40-60kg body weight. For other patients of 60-80kg or 80-100kg body weight, the mini axial pumps of 23mm and 25mm outer diameter had been developed before, these devices were acknowledged to be the world smallest LVADs by Guinness World Record Center in 2004.The permanent maglev radial pump weighing 150g is a shaft-less centrifugal pump with permanent magnetic bearings developed by the author. It needs no second coil for suspension of the rotor except the motor coil, different from all other maglev pumps developed in USA, Japan, European, etc. Thus no detecting and controlling systems as well as no additional power supply for maglev are necessary. The pump can produce a blood flow up to as large as 10l/min against 100mmHg pressure.An implantable and durable blood pump will be a viable alternative to natural donor heart for transplantation.
Vibration analysis of the maglev guideway with the moving load
NASA Astrophysics Data System (ADS)
Wang, H. P.; Li, J.; Zhang, K.
2007-09-01
The response of the guideway induced by moving maglev vehicle is investigated in this paper. The maglev vehicle is simplified as evenly distributed force acting on the guideway at constant speed. According to the experimental line, the guideway structure of rail-sleeper-bridge is simplified as Bernoulli-Euler (B-E) beam—evenly distributed spring—simply supported B-E beam structure; thus, double deck model of the maglev guideway is constructed which can more accurately reflect the dynamic characteristic of the experimental line. The natural frequency and mode are deduced based on the theoretical model. The relationship between structural parameters and natural frequency are exploited by employing the numerical calculation method. The way to suppress the vehicle-guideway interaction by regulating the structural parameter is also discussed here. Using the normal coordinate transformation method, the coupled differential equations of motion of the maglev guideway are converted into a set of uncoupled equations. The closed-form solutions for the response of the guideway subjecting the moving load are derived. It is noted that the moving load would not induce the vehicle-guideway interaction oscillation. The analysis of the guideway impact factor implies that at some position of the guideway, the deflection may decrease with the increase of the speed of the load; several extreme value of the guideway displacement will appear induced by different speeds, with different acting place, the speeds are different either. The final numerical simulation verifies these conclusions.
Electrodynamic tether system study
NASA Technical Reports Server (NTRS)
1987-01-01
The purpose of this program is to define an Electrodynamic Tether System (ETS) that could be erected from the space station and/or platforms to function as an energy storage device. A schematic representation of the ETS concept mounted on the space station is presented. In addition to the hardware design and configuration efforts, studies are also documented involving simulations of the Earth's magnetic fields and the effects this has on overall system efficiency calculations. Also discussed are some preliminary computer simulations of orbit perturbations caused by the cyclic/night operations of the ETS. System cost estimates, an outline for future development testing for the ETS system, and conclusions and recommendations are also provided.
Middle atmospheric electrodynamics
NASA Technical Reports Server (NTRS)
Kelley, M. C.
1983-01-01
A review is presented of the advances made during the last few years with respect to the study of the electrodynamics in the earth's middle atmosphere. In a report of the experimental work conducted, attention is given to large middle atmospheric electric fields, the downward coupling of high altitude processes into the middle atmosphere, and upward coupling of tropospheric processes into the middle atmosphere. It is pointed out that new developments in tethered balloons and superpressure balloons should greatly increase the measurement duration of earth-ionospheric potential measurements and of stratospheric electric field measurements in the next few years. Theoretical work considered provides an excellent starting point for study of upward coupling of transient and dc electric fields. Hays and Roble (1979) were the first to construct a model which included orographic features as well as the classical thunderstorm generator.
Entropy concepts in classical electrodynamics
NASA Astrophysics Data System (ADS)
Cole, Daniel C.
2002-11-01
Aspects of entropy and related thermodynamic analyses are discussed here that have been deduced in recent years in the area of classical electrodynamics. A motivating factor for most of this work has been an attempted theory of nature often called, "stochastic electrodynamics" (SED). This theory involves classical electrodynamics (Maxwell's equations plus the relativistic version of Newton's second law of motion for particles), but with the consideration that motion and fluctuations should not necessarily be assumed to reduce to zero at temperature T = 0. Both fairly subtle and rather blatant assumptions were often imposed in early thermodynamic analyses of electrodynamic systems that prevented the analyses from being sufficiently general to account for these "zero-point" properties, which hindered classical physics from being able to better account for quantum mechanical phenomena observed in nature. In turn, such thermodynamic considerations have helped motivate many of the key ideas of SED.
Timelike Momenta In Quantum Electrodynamics
DOE R&D Accomplishments Database
Brodsky, S. J.; Ting, S. C. C.
1965-12-01
In this note we discuss the possibility of studying the quantum electrodynamics of timelike photon propagators in muon or electron pair production by incident high energy muon or electron beams from presently available proton or electron accelerators.
Electrodynamic Arrays Having Nanomaterial Electrodes
NASA Technical Reports Server (NTRS)
Trigwell, Steven (Inventor); Biris, Alexandru S. (Inventor); Calle, Carlos I. (Inventor)
2013-01-01
An electrodynamic array of conductive nanomaterial electrodes and a method of making such an electrodynamic array. In one embodiment, a liquid solution containing nanomaterials is deposited as an array of conductive electrodes on a substrate, including rigid or flexible substrates such as fabrics, and opaque or transparent substrates. The nanomaterial electrodes may also be grown in situ. The nanomaterials may include carbon nanomaterials, other organic or inorganic nanomaterials or mixtures.
Two applications of axion electrodynamics
NASA Technical Reports Server (NTRS)
Wilczek, Frank
1987-01-01
The equations of axion electrodynamics are studied. Variations in the axion field can give rise to peculiar distributions of charge and current. These effects provide a simple understanding of the fractional electric charge on dyons and of some recently discovered oddities in the electrodynamics of antiphase boundaries in PbTe. Some speculations regarding the possible occurrence of related phenomena in other solids are presented.
Superconducting Electromagnetic Suspension (EMS) system for Grumman Maglev concept
NASA Technical Reports Server (NTRS)
Kalsi, Swarn S.
1994-01-01
The Grumman developed Electromagnetic Suspension (EMS) Maglev system has the following key characteristics: a large operating airgap--40 mm; levitation at all speeds; both high speed and low speed applications; no deleterious effects on SC coils at low vehicle speeds; low magnetic field at the SC coil--less than 0.35 T; no need to use non-magnetic/non-metallic rebar in the guideway structure; low magnetic field in passenger cabin--approximately 1 G; low forces on the SC coil; employs state-of-the-art NbTi wire; no need for an active magnet quench protection system; and lower weight than a magnet system with copper coils. The EMS Maglev described in this paper does not require development of any new technologies. The system could be built with the existing SC magnet technology.
Adaptive fuzzy-neural-network control for maglev transportation system.
Wai, Rong-Jong; Lee, Jeng-Dao
2008-01-01
A magnetic-levitation (maglev) transportation system including levitation and propulsion control is a subject of considerable scientific interest because of highly nonlinear and unstable behaviors. In this paper, the dynamic model of a maglev transportation system including levitated electromagnets and a propulsive linear induction motor (LIM) based on the concepts of mechanical geometry and motion dynamics is developed first. Then, a model-based sliding-mode control (SMC) strategy is introduced. In order to alleviate chattering phenomena caused by the inappropriate selection of uncertainty bound, a simple bound estimation algorithm is embedded in the SMC strategy to form an adaptive sliding-mode control (ASMC) scheme. However, this estimation algorithm is always a positive value so that tracking errors introduced by any uncertainty will cause the estimated bound increase even to infinity with time. Therefore, it further designs an adaptive fuzzy-neural-network control (AFNNC) scheme by imitating the SMC strategy for the maglev transportation system. In the model-free AFNNC, online learning algorithms are designed to cope with the problem of chattering phenomena caused by the sign action in SMC design, and to ensure the stability of the controlled system without the requirement of auxiliary compensated controllers despite the existence of uncertainties. The outputs of the AFNNC scheme can be directly supplied to the electromagnets and LIM without complicated control transformations for relaxing strict constrains in conventional model-based control methodologies. The effectiveness of the proposed control schemes for the maglev transportation system is verified by numerical simulations, and the superiority of the AFNNC scheme is indicated in comparison with the SMC and ASMC strategies.
Novel maglev pump with a combined magnetic bearing.
Onuma, Hiroyuki; Murakami, Michiko; Masuzawa, Toru
2005-01-01
The newly developed pump is a magnetically levitated centrifugal blood pump in which active and passive magnetic bearings are integrated to construct a durable ventricular assist device. The developed maglev centrifugal pump consists of an active magnetic bearing, a passive magnetic bearing, a levitated impeller, and a motor stator. The impeller is set between the active magnetic bearing and the motor stator. The active magnetic bearing uses four electromagnets to control the tilt and the axial position of the impeller. The radial movement of the levitated impeller is restricted with the passive stability dependent upon the top stator and the passive permanent magnetic bearing to reduce the energy consumption and the control system complexity. The top stator was designed based upon a magnetic field analysis to develop the maglev pump with sufficient passive stability in the radial direction. By implementing this analysis design, the oscillating amplitude of the impeller in the radial direction was cut in half when compared with the simple shape stator. This study concluded that the newly developed maglev centrifugal pump displayed excellent levitation performance and sufficient pump performance as a ventricular assist device.
Summary Presentation of the Electrodynamics Interactions Panel
NASA Technical Reports Server (NTRS)
Stone, N. H.
1985-01-01
Technological and scientific uses of electrodynamic tethers in space are considered. Areas of concern for such applications of electrodynamic tethers are enumerated. Thrust and power generation using tethers are discussed.
Johnson, L.R.; Rote, D.M.; Hull, J.R.; Coffey, H.T.; Daley, J.G.; Giese, R.F.
1989-04-01
This study was undertaken to (1) evaluate the potential contribution of high-temperature superconductors (HTSCs) to the technical and economic feasibility of magnetically levitated (maglev) vehicles, (2) determine the status of maglev transportation research in the United States and abroad, (3) identify the likelihood of a significant transportation market for high-speed maglev vehicles, and (4) provide a preliminary assessment of the potential energy and economic benefits of maglev systems. HTSCs should be considered as an enhancing, rather than an enabling, development for maglev transportation because they should improve reliability and reduce energy and maintenance costs. Superconducting maglev transportation technologies were developed in the United States in the late 1960s and early 1970s. Federal support was withdrawn in 1975, but major maglev transportation programs were continued in Japan and West Germany, where full-scale prototypes now carry passengers at speeds of 250 mi/h in demonstration runs. Maglev systems are generally viewed as very-high-speed train systems, but this study shows that the potential market for maglev technology as a train system, e.g., from one downtown to another, is limited. Rather, aircraft and maglev vehicles should be seen as complementing rather than competing transportation systems. If maglev systems were integrated into major hub airport operations, they could become economical in many relatively high-density US corridors. Air traffic congestion and associated noise and pollutant emissions around airports would also be reduced. 68 refs., 26 figs., 16 tabs.
Circuit quantum electrodynamics
NASA Astrophysics Data System (ADS)
Bishop, Lev Samuel
Circuit Quantum Electrodynamics (cQED), the study of the interaction between superconducting circuits behaving as artificial atoms and 1-dimensional transmission-line resonators, has shown much promise for quantum information processing tasks. For the purposes of quantum computing it is usual to approximate the artificial atoms as 2-level qubits, and much effort has been expended on attempts to isolate these qubits from the environment and to invent ever more sophisticated control and measurement schemes. Rather than focussing on these technological aspects of the field, this thesis investigates the opportunities for using these carefully engineered systems for answering questions of fundamental physics. The low dissipation and small mode volume of the circuits allows easy access to the strong-coupling regime of quantum optics, where one can investigate the interaction of light and matter at the level of single atoms and photons. A signature of strong coupling is the splitting of the cavity transmission peak into a pair of resolvable peaks when a single resonant atom is placed inside the cavity---an effect known as vacuum Rabi splitting. The cQED architecture is ideally suited for going beyond this linear response effect. This thesis shows that increasing the drive power results in two unique nonlinear features in the transmitted heterodyne signal: the supersplitting of each vacuum Rabi peak into a doublet, and the appearance of additional peaks with the characteristic n spacing of the Jaynes-Cummings ladder. These constitute direct evidence for the coupling between the quantized microwave field and the anharmonic spectrum of a superconducting qubit acting as an artificial atom. This thesis also addresses the idea of Bell tests, which are experiments that aim to disprove certain types of classical theories, presenting a proposed method for preparing maximally entangled 3-qubit states via a 'preparation by measurement' scheme using an optimized filter on the time
Plasma contactors for electrodynamic tether
NASA Technical Reports Server (NTRS)
Patterson, Michael J.; Wilbur, Paul J.
1986-01-01
The role plasma contactors play in effective electrodynamic tether operation is discussed. Hollow cathodes and hollow cathode-based plasma sources have been identified as leading candidates for the electrodynamic tether plasma contactor. Present experimental efforts to evaluate the suitability of these devices as plasma contactors, conducted concurrently at NASA Lewis Research Center and Colorado State University, are reviewed. These research programs include the definition of preliminary plasma contactor designs, and the characterization of their operation both as electron emitters and electron collectors to and from a simulated space plasma. Results indicate that ampere-level electron currents, sufficient for electrodynamic tether operation, can be exchanged between hollow cathode-based plasma contactors and a dilute plasma.
Electrodynamics payloads for small rockets
NASA Technical Reports Server (NTRS)
Croskey, C. L.; Hale, L. C.; Mitchell, J. D.; Mccarthy, S. P.; Goodnow, K. J.; Li, C.; Goldberg, R. A.
1992-01-01
Totally integrated design facilitates electrical cleanliness and light weight, which are necessary in subsonic parachute-borne payloads for electrodynamics investigations. 'Blunt' probes measure ion conductivity, as do Gerdien condensers. Recent finite-element computer analyses combining flow and electrodynamics have resolved problems in determining ion densities and mobilities from Gerdien data. Three-axis electric fields are measured with deployable boom-mounted electrodes from dc through VLF. Splitting the cylindrical payload with an insulator and measuring the current between halves has provided a vertical Maxwell current detector mechanically rigid enough to measure, at ELF, energy related to coupling. A nose tip 'Smith' probe turbulence measurement is usually performed on ascent. Other instrumentation, such as photo-ionization sources and X-ray detectors, can also be included. These electrodynamic measurement payloads are about one meter in length and have a mass of about 9 kg. They can be launched with an Orion-class or smaller vehicle.
Quantization of general linear electrodynamics
Rivera, Sergio; Schuller, Frederic P.
2011-03-15
General linear electrodynamics allow for an arbitrary linear constitutive relation between the field strength 2-form and induction 2-form density if crucial hyperbolicity and energy conditions are satisfied, which render the theory predictive and physically interpretable. Taking into account the higher-order polynomial dispersion relation and associated causal structure of general linear electrodynamics, we carefully develop its Hamiltonian formulation from first principles. Canonical quantization of the resulting constrained system then results in a quantum vacuum which is sensitive to the constitutive tensor of the classical theory. As an application we calculate the Casimir effect in a birefringent linear optical medium.
Lift to Drag Ratio Analysis in Magnetic Levitation with an Electrodynamic Wheel
NASA Astrophysics Data System (ADS)
Gutarra-Leon, Angel; Cordrey, Vincent; Majewski, Walerian
Our experiments explored inductive magnetic levitation (MagLev) using simple permanent magnets and conductive tracks. Our investigations used a circular Halbach array with a 1 Tesla variable magnetic field on the outer rim of the ring. Such a system is usually called an Electrodynamic Wheel (EDW). Rotating this wheel around a horizontal axis above or below a flat conducting surface should induce eddy currents in said surface through the variable magnetic flux. The eddy currents produce, in turn, their own magnetic fields, which interact with the magnets of the EDW. We constructed a four-inch diameter Electrodynamic Wheel using twelve Neodymium permanent magnets and demonstrated that the magnetic interactions produce both lift and drag forces on the EDW. These forces can be used for levitation and propulsion of the EDW to produce magnetic levitation without coils and complex control circuitry. We achieved full levitation of the non-magnetic aluminum and copper plates. Our results confirm the expected behavior of lift to drag ratio as proportional to (L/R) ω, with L and R being the inductance and resistance of the track plate, and ω being the angular velocity of the magnetic flux. Supported by grants from the Virginia Academy of Science, Society of Physics Students, Virginia Community College System, and the NVCC Educational Foundation.
Electrodynamic Dust Shield Demonstrator
NASA Technical Reports Server (NTRS)
Stankie, Charles G.
2013-01-01
The objective of the project was to design and manufacture a device to demonstrate a new technology developed by NASA's Electrostatics and Surface Physics Laboratory. The technology itself is a system which uses magnetic principles to remove regolith dust from its surface. This project was to create an enclosure that will be used to demonstrate the effectiveness of the invention to The Office of the Chief Technologist. ONE of the most important challenges of space exploration is actually caused by something very small and seemingly insignificant. Dust in space, most notably on the moon and Mars, has caused many unforeseen issues. Dirt and dust on Earth, while a nuisance, can be easily cleaned and kept at bay. However, there is considerably less weathering and erosion in space. As a result, the microscopic particles are extremely rough and abrasive. They are also electrostatically charged, so they cling to everything they make contact with. This was first noted to be a major problem during the Apollo missions. Dust would stick to the spacesuits, and could not be wiped off as predicted. Dust was brought back into the spacecraft, and was even inhaled by astronauts. This is a major health hazard. Atmospheric storms and other events can also cause dust to coat surfaces of spacecraft. This can cause abrasive damage to the craft. The coating can also reduce the effectiveness of thermal insulation and solar panels.' A group of engineers at Kennedy Space Center's Electrostatics and Surface Physics Laboratory have developed a new technology, called the Electrodynamic Dust Shield, to help alleviate these problems. It is based off of the electric curtain concept developed at NASA in 1967. "The EDS is an active dust mitigation technology that uses traveling electric fields to transport electrostatically charged dust particles along surfaces. To generate the traveling electric fields, the EDS consists of a multilayer dielectric coating with an embedded thin electrode grid
Electrodynamic Tethers for Spacecraft Propulsion
NASA Technical Reports Server (NTRS)
Johnson, Les; Estes, Robert D.; Lorenzini, Enrico; Martinez-Sanchez, Manuel; Sanmartin, Juan; Vas, Irwin
1998-01-01
Relatively short electrodynamic tethers can use solar power to 'push' against a planetary magnetic field to achieve propulsion without the expenditure of propellant. The groundwork has been laid for this type of propulsion. NASA began developing tether technology for space applications in the 1960's. Important recent milestones include retrieval of a tether in space (TSS-1, 1992), successful deployment of a 20-km-long tether in space (SEDS-1, 1993), and operation of an electrodynamic tether with tether current driven in both directions-power and thrust modes (PMG, 1993). The planned Propulsive Small Expendable Deployer System (ProSEDS) experiment will demonstrate electrodynamic tether thrust during its flight in early 2000. ProSEDS will use the flight-proven Small Expendable Deployer System (SEDS) to deploy a 5 km bare copper tether from a Delta II upper stage to achieve approximately 0.4 N drag thrust, thus deorbiting the stage. The experiment will use a predominantly 'bare' tether for current collection in lieu of the endmass collector and insulated tether approach used on previous missions. Theory and ground-based plasma chamber testing indicate that the bare tether is a highly-efficient current collector. The flight experiment is a precursor to utilization of the technology on the International Space Station for reboost application and the more ambitious electrodynamic tether upper stage demonstration mission which will be capable of orbit raising, lowering and inclination changes - all using electrodynamic thrust. In addition, the use of this type of propulsion may be attractive for future missions at Jupiter and any other planetary body with a magnetosphere.
On the unsteady-motion theory of magnetic forces for maglev
Chen, S.S.; Zhu, S.; Cai, Y.
1993-11-01
Motion-dependent magnetic forces are the key elements in the study of magnetically levitated vehicle (maglev) system dynamics. In the past, most maglev-system designs were based on a quasisteady-motion theory of magnetic forces. This report presents an experimental and analytical study that will enhance our understanding of the role of unsteady-motion-dependent magnetic forces and demonstrate an experimental technique that can be used to measure those unsteady magnetic forces directly. The experimental technique provides a useful tool to measure motion-dependent magnetic forces for the prediction and control of maglev systems.
On spacetime structure and electrodynamics
NASA Astrophysics Data System (ADS)
Ni, Wei-Tou
2016-10-01
Electrodynamics is the most tested fundamental physical theory. Relativity arose from the completion of Maxwell-Lorentz electrodynamics. Introducing the metric gij as gravitational potential in 1913, versed in general (coordinate-)covariant formalism in 1914 and shortly after the completion of general relativity, Einstein put the Maxwell equations in general covariant form with only the constitutive relation between the excitation and the field dependent on and connected by the metric in 1916. Further clarification and developments by Weyl in 1918, Murnaghan in 1921, Kottler in 1922 and Cartan in 1923 together with the corresponding developments in electrodynamics of continuous media by Bateman in 1910, Tamm in 1924, Laue in 1952 and Post in 1962 established the premetric formalism of electrodynamics. Since almost all phenomena electrodynamics deal with have energy scales much lower than the Higgs mass energy and intermediate boson energy, electrodynamics of continuous media should be applicable and the constitutive relation of spacetime/vacuum should be local and linear. What is the key characteristic of the spacetime/vacuum? It is the Weak Equivalence Principle I (WEP I) for photons/wave packets of light which states that the spacetime trajectory of light in a gravitational field depends only on its initial position and direction of propagation, and does not depend on its frequency (energy) and polarization, i.e. nonbirefringence of light propagation in spacetime/vacuum. With this principle it is proved by the author in 1981 in the weak field limit, and by Lammerzahl and Hehl in 2004 together with Favaro and Bergamin in 2011 without assuming the weak-field condition that the constitutive tensor must be of the core metric form with only two additional degrees of freedom — the pseudoscalar (Abelian axion or EM axion) degree of freedom and the scalar (dilaton) degree of freedom (i.e. metric with axion and dilaton). In this paper, we review this connection and the
A finite element method for analysis of vibration induced by maglev trains
NASA Astrophysics Data System (ADS)
Ju, S. H.; Ho, Y. S.; Leong, C. C.
2012-07-01
This paper developed a finite element method to perform the maglev train-bridge-soil interaction analysis with rail irregularities. An efficient proportional integral (PI) scheme with only a simple equation is used to control the force of the maglev wheel, which is modeled as a contact node moving along a number of target nodes. The moving maglev vehicles are modeled as a combination of spring-damper elements, lumped mass and rigid links. The Newmark method with the Newton-Raphson method is then used to solve the nonlinear dynamic equation. The major advantage is that all the proposed procedures are standard in the finite element method. The analytic solution of maglev vehicles passing a Timoshenko beam was used to validate the current finite element method with good agreements. Moreover, a very large-scale finite element analysis using the proposed scheme was also tested in this paper.
A method to enhance the curve negotiation performance of HTS Maglev
NASA Astrophysics Data System (ADS)
Che, T.; Gou, Y. F.; Deng, Z. G.; Zheng, J.; Zheng, B. T.; Chen, P.
2015-09-01
High temperature superconducting (HTS) Maglev has attracted more and more attention due to its special self-stable characteristic, and much work has been done to achieve its actual application, but the research about the curve negotiation is not systematic and comprehensive. In this paper, we focused on the change of the lateral displacements of the Maglev vehicle when going through curves under different velocities, and studied the change of the electromagnetic forces through experimental methods. Experimental results show that setting an appropriate initial eccentric distance (ED), which is the distance between the center of the bulk unit and the center of the permanent magnet guideway (PMG), when cooling the bulks is favorable for the Maglev system’s curve negotiation. This work will provide some available suggestions for improving the curve negotiation performance of the HTS Maglev system.
Control of maglev vehicles with aerodynamic and guideway disturbances
NASA Technical Reports Server (NTRS)
Flueckiger, Karl; Mark, Steve; Caswell, Ruth; Mccallum, Duncan
1994-01-01
A modeling, analysis, and control design methodology is presented for maglev vehicle ride quality performance improvement as measured by the Pepler Index. Ride quality enhancement is considered through active control of secondary suspension elements and active aerodynamic surfaces mounted on the train. To analyze and quantify the benefits of active control, the authors have developed a five degree-of-freedom lumped parameter model suitable for describing a large class of maglev vehicles, including both channel and box-beam guideway configurations. Elements of this modeling capability have been recently employed in studies sponsored by the U.S. Department of Transportation (DOT). A perturbation analysis about an operating point, defined by vehicle and average crosswind velocities, yields a suitable linearized state space model for multivariable control system analysis and synthesis. Neglecting passenger compartment noise, the ride quality as quantified by the Pepler Index is readily computed from the system states. A statistical analysis is performed by modeling the crosswind disturbances and guideway variations as filtered white noise, whereby the Pepler Index is established in closed form through the solution to a matrix Lyapunov equation. Data is presented which indicates the anticipated ride quality achieved through various closed-loop control arrangements.
Carl Neumann's Contributions to Electrodynamics
NASA Astrophysics Data System (ADS)
Schlote, Karl-Heinz
2004-09-01
I examine the publications of Carl Neumann (1832 1925) on electrodynamics, which constitute a major part of his work and which illuminate his approach to mathematical physics. I show how Neumann contributed to physics at an important stage in its development and how his work led to a polemic with Hermann Helmholtz (1821 1894). Neumann advanced and extended the ideas of the Königsberg school of mathematical physics. His investigations were aimed at founding a mathematically exact physical theory of electrodynamics, following the approach of Carl G.J. Jacobi (1804 1851) on the foundation of a physical theory as outlined in Jacobi’s lectures on analytical mechanics. Neumann’s work also shows how he clung to principles that impeded him in appreciating and developing new ideas such as those on field theory that were proposed by Michael Faraday (1791 1867) and James Clerk Maxwell (1831 1879).
Photon propagator for axion electrodynamics
Itin, Yakov
2007-10-15
The axion modified electrodynamics is usually used as a model for description of possible violation of Lorentz invariance in field theory. The low-energy manifestation of Lorentz violation can hopefully be observed in experiments with electromagnetic waves. It justifies the importance of studying how a small axion addition can modify the wave propagation. Although a constant axion does not contribute to the dispersion relation at all, even a slowly varying axion field destroys the light cone structure. In this paper, we study the wave propagation in the axion modified electrodynamics in the framework of the premetric approach. In addition to the modified dispersion relation, we derive the axion generalization of the photon propagator in Feynman and Landau gauge. Our consideration is free of the usual restriction to the constant gradient axion field. It is remarkable that the axion modified propagator is Hermitian. Consequently, the dissipation effects are absent even in the phenomenological model considered here.
Electrodynamics and Spacetime Geometry: Foundations
NASA Astrophysics Data System (ADS)
Cabral, Francisco; Lobo, Francisco S. N.
2016-11-01
We explore the intimate connection between spacetime geometry and electrodynamics. This link is already implicit in the constitutive relations between the field strengths and excitations, which are an essential part of the axiomatic structure of electromagnetism, clearly formulated via integration theory and differential forms. We review the foundations of classical electromagnetism based on charge and magnetic flux conservation, the Lorentz force and the constitutive relations. These relations introduce the conformal part of the metric and allow the study of electrodynamics for specific spacetime geometries. At the foundational level, we discuss the possibility of generalizing the vacuum constitutive relations, by relaxing the fixed conditions of homogeneity and isotropy, and by assuming that the symmetry properties of the electro-vacuum follow the spacetime isometries. The implications of this extension are briefly discussed in the context of the intimate connection between electromagnetism and the geometry (and causal structure) of spacetime.
Pyroshock testing-electrodynamic shakers
NASA Astrophysics Data System (ADS)
Smallwood, David O.
2002-05-01
Far field pyroshock (accelerations less than a few hundred grams, and bandwidths less than a few kHz) can be simulated on electrodynamic shakers. Typically, the specification is in terms of the shock response spectrum (SRS). Wave forms are synthesized which will match the required SRS. The process is not unique, as many wave forms can have essentially the same SRS. Sometimes additional restrictions are placed on the synthesized wave form. Most common are restrictions on the duration of the wave form. The process of synthesizing wave forms, which will match an SRS and conform to the limitations of electrodynamic shakers, will be described. The methods used to reproduce these wave forms on the shaker will then be discussed.
Electrodynamics and Spacetime Geometry: Foundations
NASA Astrophysics Data System (ADS)
Cabral, Francisco; Lobo, Francisco S. N.
2017-02-01
We explore the intimate connection between spacetime geometry and electrodynamics. This link is already implicit in the constitutive relations between the field strengths and excitations, which are an essential part of the axiomatic structure of electromagnetism, clearly formulated via integration theory and differential forms. We review the foundations of classical electromagnetism based on charge and magnetic flux conservation, the Lorentz force and the constitutive relations. These relations introduce the conformal part of the metric and allow the study of electrodynamics for specific spacetime geometries. At the foundational level, we discuss the possibility of generalizing the vacuum constitutive relations, by relaxing the fixed conditions of homogeneity and isotropy, and by assuming that the symmetry properties of the electro-vacuum follow the spacetime isometries. The implications of this extension are briefly discussed in the context of the intimate connection between electromagnetism and the geometry (and causal structure) of spacetime.
Accelerator and electrodynamics capability review
Jones, Kevin W
2010-01-01
Los Alamos National Laboratory (LANL) uses capability reviews to assess the science, technology and engineering (STE) quality and institutional integration and to advise Laboratory Management on the current and future health of the STE. Capability reviews address the STE integration that LANL uses to meet mission requirements. The Capability Review Committees serve a dual role of providing assessment of the Laboratory's technical contributions and integration towards its missions and providing advice to Laboratory Management. The assessments and advice are documented in reports prepared by the Capability Review Committees that are delivered to the Director and to the Principal Associate Director for Science, Technology and Engineering (PADSTE). Laboratory Management will use this report for STE assessment and planning. LANL has defined fifteen STE capabilities. Electrodynamics and Accelerators is one of the seven STE capabilities that LANL Management (Director, PADSTE, technical Associate Directors) has identified for review in Fiscal Year (FY) 2010. Accelerators and electrodynamics at LANL comprise a blend of large-scale facilities and innovative small-scale research with a growing focus on national security applications. This review is organized into five topical areas: (1) Free Electron Lasers; (2) Linear Accelerator Science and Technology; (3) Advanced Electromagnetics; (4) Next Generation Accelerator Concepts; and (5) National Security Accelerator Applications. The focus is on innovative technology with an emphasis on applications relevant to Laboratory mission. The role of Laboratory Directed Research and Development (LDRD) in support of accelerators/electrodynamics will be discussed. The review provides an opportunity for interaction with early career staff. Program sponsors and customers will provide their input on the value of the accelerator and electrodynamics capability to the Laboratory mission.
Optimal Control of Electrodynamic Tethers
2008-06-01
method.46 Even though the derivation that produced Eq. (11) required integration over a hypothetical integer number of revolutions, the optimizer ... approach to multi-revolution, long time scale optimal control of an electrodynamic tether is investigated for a tethered satellite system in Low Earth...time scale approach is used to capture the effects of the Earth’s rotating tilted magnetic field. Optimal control solutions are achieved using a
Quantum electrodynamics for vector mesons.
Djukanovic, Dalibor; Schindler, Matthias R; Gegelia, Jambul; Scherer, Stefan
2005-07-01
Quantum electrodynamics for rho mesons is considered. It is shown that, at the tree level, the value of the gyromagnetic ratio of the rho+ is fixed to 2 in a self-consistent effective quantum field theory. Further, the mixing parameter of the photon and the neutral vector meson is equal to the ratio of electromagnetic and strong couplings, leading to the mass difference M(rho0)-M(rho+/-) approximately 1 MeV at tree order.
Electrodynamics on extrasolar giant planets
Koskinen, T. T.; Yelle, R. V.; Lavvas, P.; Cho, J. Y-K.
2014-11-20
Strong ionization on close-in extrasolar giant planets (EGPs) suggests that their atmospheres may be affected by ion drag and resistive heating arising from wind-driven electrodynamics. Recent models of ion drag on these planets, however, are based on thermal ionization only and do not include the upper atmosphere above the 1 mbar level. These models are also based on simplified equations of resistive magnetohydrodynamics that are not always valid in extrasolar planet atmospheres. We show that photoionization dominates over thermal ionization over much of the dayside atmosphere above the 100 mbar level, creating an upper ionosphere dominated by ionization of H and He and a lower ionosphere dominated by ionization of metals such as Na, K, and Mg. The resulting dayside electron densities on close-in exoplanets are higher than those encountered in any planetary ionosphere of the solar system, and the conductivities are comparable to the chromosphere of the Sun. Based on these results and assumed magnetic fields, we constrain the conductivity regimes on close-in EGPs and use a generalized Ohm's law to study the basic effects of electrodynamics in their atmospheres. We find that ion drag is important above the 10 mbar level where it can also significantly alter the energy balance through resistive heating. Due to frequent collisions of the electrons and ions with the neutral atmosphere, however, ion drag is largely negligible in the lower atmosphere below the 10 mbar level for a reasonable range of planetary magnetic moments. We find that the atmospheric conductivity decreases by several orders of magnitude in the night side of tidally locked planets, leading to a potentially interesting large-scale dichotomy in electrodynamics between the day and night sides. A combined approach that relies on UV observations of the upper atmosphere, phase curve and Doppler measurements of global dynamics, and visual transit observations to probe the alkali metals can potentially be
Asymptotic structure of electrodynamics revisited
NASA Astrophysics Data System (ADS)
Herdegen, Andrzej
2017-03-01
We point out that recently published analyses of null and timelike infinity and long-range structures in electrodynamics to large extent rediscover results present in the literature. At the same time, some of the conclusions these recent works put forward may prove controversial. In view of these facts, we find it desirable to revisit the analysis taken up more than two decades ago, starting from earlier works on null infinity by other authors.
Critical Researches on General Electrodynamics
NASA Astrophysics Data System (ADS)
Ritz, Walter; Fritzius, Robert
1980-11-01
Electric and electrodynamic phenomena have acquired in the course of these last years more and more importance. They include Optics, the laws of radiation and the innumerable molecular phenomena associated with the presence of charged centers, ions and electrons. Finally, with the notion of electromagnetic mass, Mechanics itself seems obliged to become a chapter of General Electrodynamics. In the form given to it by H. A. Lorentz, Maxwell's theory would thus become the turning point towards a new conception of nature, where the laws of electrodynamics, considered as primary, would contain the laws of motion as special cases and would play the fundamental role in the physical theories which, until now, have belonged to Mechanics. Under these circumstances, it is plainly desirable to have a rigorous criticism of the foundations of this theory, to give it the degree of clarity and precision that Mechanics itself reached only recently after much controversy. It is in order to ask which hypotheses are essential and can be deduced from observations, which others are logically useless or can be discarded without experience ceasing to be adequately represented, and finally, which are those which can be, and should be rejected; a question which is asked principally in regard to absolute motion.
Response of a maglev vehicle moving on a series of guideways with differential settlement
NASA Astrophysics Data System (ADS)
Yau, J. D.
2009-07-01
The objective of this study is to investigate the dynamic response of a maglev (magnetically levitated) vehicle traveling over a series of guideway girders undergoing ground support settlement. The maglev vehicle is simulated as a rigid car body supported by a rigid levitation frame using a uniformly distributed spring-dashpot system, and the guideway unit is modeled as a series of simple beams with identical span. To carry out the interaction dynamics of maglev vehicle/guideway system, this study adopts a PI (proportional-integral) controller with constant tuning gains based on Ziegler-Nicholas (Z-N) method to regulate the electromagnetic forces between the magnetic-wheels and guide-rail. For the inclusion of support movements, the total response of the simple beam is decomposed into two parts: the static response due to support settlement and the dynamic component caused by inertia effect of beam vibration. Once the static displacement for a simple beam undergoing vertical support movements is derived, the remaining dynamic response of the maglev vehicle/guideway system is solved by Galerkin's method and computed by an iterative approach using Newmark's finite difference formulas. Numerical studies indicate that the increase in levitation gap for a maglev vehicle may result in larger vehicle's response, but the response of the maglev vehicle with smaller air gap will be significantly amplified at higher speeds once ground settlement appears at the guideway supports.
NASA Astrophysics Data System (ADS)
Wang, Bo; Zheng, Jun; Si, Shuaishuai; Qian, Nan; Li, Haitao; Li, Jipeng; Deng, Zigang
2016-07-01
Off-centre operation of high-temperature superconducting (HTS) maglev systems caused by inevitable conditions such as the misregistration of vehicle, crosswind and curve negotiation, may change the distribution of the trapped flux in the HTS bulks and the magnetic interaction between HTS bulks and the PMG. It impacts on the performance of HTS maglev, and more seriously makes the maglev vehicle overturned. Therefore, understanding the performance of the HTS maglev in off-center operation is very important. In this paper, the dynamic response characteristics of a cryostat with twenty-four onboard YBaCuO superconductor bulks were experimentally investigated at different eccentric distances under loads before the initial FC process. Parameters such as vibration accelerations, displacement, natural frequency and dynamic stiffness were acquired and analyzed via the B&K vibration analyzer and laser displacement sensors. Results suggest that the natural frequency and dynamic stiffness of the maglev vehicle would be obviously reduced with the eccentric distance, posing negative effects on the stability of HTS maglev.
De-centralized and centralized control for realistic EMS Maglev systems
NASA Astrophysics Data System (ADS)
Moawad, Mohamed M. Aly M.
A comparative study of de-centralized and centralized controllers when used with real EMS Maglev Systems is introduced. This comparison is divided into two parts. Part I is concerned with numerical simulation and experimental testing on a two ton six-magnet EMS Maglev vehicle. Levitation and lateral control with these controllers individually and when including flux feedback control in combination with these controllers to enhance stability are introduced. The centralized controller is better than the de-centralized one when the system is exposed to a lateral disturbing force such as wind gusts. The flux feedback control when combined with de-centralized or centralized controllers does improve the stability and is more resistant and robust with respect to the air gap variations. Part II is concerned with the study of Maglev vehicle-girder dynamic interaction system and the comparison between these two controllers on this typical system based on performance and ride quality achieved. Numerical simulations of the ODU EMS Maglev vehicle interacting with girder are conducted with these two different controllers. The de-centralized and centralized control for EMS Maglev systems that interact with a flexible girder provides similar ride quality. Centralized control with flux feedback could be the best controller for the ODU Maglev system when operating on girder. The centralized control will guarantee the suppression of the undesired lateral displacements; hence it will provide smoother ride quality. Flux feedback will suppress air gap variations due to the track discontinuities.
Continuous Variable Teleportation Within Stochastic Electrodynamics
NASA Astrophysics Data System (ADS)
Carmichael, H. J.; Nha, Hyunchul
2004-12-01
Stochastic electrodynamics provides a local realistic interpretation of the continuous variable teleportation of coherent light. Time-domain simulations illustrate broadband features of the teleportation process.
Fractional Order PIλDμ Control for Maglev Guiding System
NASA Astrophysics Data System (ADS)
Hu, Qing; Hu, Yuwei
To effectively suppress the external disturbances and parameter perturbation problem of the maglev guiding system, and improve speed and robustness, the electromagnetic guiding system is exactly linearized using state feedback method, Fractional calculus theory is introduced, the order of integer order PID control was extended to the field of fractional, then fractional order PIλDμ Controller was presented, Due to the extra two adjustable parameters compared with traditional PID controller, fractional order PIλDμ controllers were expected to show better control performance. The results of the computer simulation show that the proposed controller suppresses the external disturbances and parameter perturbation of the system effectively; the system response speed was increased; at the same time, it had flexible structure and stronger robustness.
A model of nonlinear electrodynamics
Kruglov, S.I.
2015-02-15
A new model of nonlinear electrodynamics with two parameters is investigated. We also consider a model with one dimensional parameter. It was shown that the electric field of a point-like charge is not singular at the origin and there is the finiteness of the static electric energy of point-like charged particle. We obtain the canonical and symmetrical Belinfante energy–momentum tensors and dilatation currents. It is demonstrated that the dilatation symmetry and dual symmetry are broken in the models suggested. We have calculated the static electric energy of point-like particles.
Electrodynamics at the highest energies
Klein, Spencer R.
2002-06-17
At very high energies, the bremsstrahlung and pair production cross sections exhibit complex behavior due to the material in which the interactions occur. The cross sections in dense media can be dramatically different than for isolated atoms. This writeup discusses these in-medium effects, emphasizing how the cross section has different energy and target density dependencies in different regimes. Data from SLAC experiment E-146 will be presented to confirm the energy and density scaling. Finally, QCD analogs of the electrodynamics effects will be discussed.
Universe acceleration and nonlinear electrodynamics
NASA Astrophysics Data System (ADS)
Kruglov, S. I.
2015-12-01
A new model of nonlinear electrodynamics with a dimensional parameter β coupled to gravity is considered. We show that an accelerated expansion of the universe takes place if the nonlinear electromagnetic field is the source of the gravitational field. A pure magnetic universe is investigated, and the magnetic field drives the universe to accelerate. In this model, after the big bang, the universe undergoes inflation and the accelerated expansion and then decelerates approaching Minkowski spacetime asymptotically. We demonstrate the causality of the model and a classical stability at the deceleration phase.
Electrodynamic Tethers for Spacecraft Propulsion
NASA Technical Reports Server (NTRS)
Johnson, Les
2009-01-01
Electrodynamic (Drag) Tether Thrust Principles: a) Uses both solar energy and consumes no propellant. b) Tether's orbital velocity v (approx. 7500 m/s) through North-pointing geomagnetic field B(sub north) (0.18 - 0.32 Gauss) induces voltage (35 - 160 V/km) in tether. c) Return current is through surrounding plasma. d) Current I produces a drag thrust force F on the tether. e) Magnetic force F from current I through insulated tether of length l: F = lI x B(sub north).
Macroscopic quantum electrodynamics and duality.
Buhmann, Stefan Yoshi; Scheel, Stefan
2009-04-10
We discuss under what conditions the duality between electric and magnetic fields is a valid symmetry of macroscopic quantum electrodynamics. It is shown that Maxwell's equations in the absence of free charges satisfy duality invariance on an operator level, whereas this is not true for Lorentz forces and atom-field couplings in general. We prove that derived quantities such as Casimir forces, local-field corrected decay rates, as well as van der Waals potentials are invariant with respect to a global exchange of electric and magnetic quantities. This exact symmetry can be used to deduce the physics of new configurations on the basis of already established ones.
A novel permanent maglev rotary LVAD with passive magnetic bearings.
Qian, K X; Yuan, H Y; Zeng, P; Ru, W M
2005-01-01
It has been widely acknowledged that permanent maglev cannot achieve stability; however, the authors have discovered that stable permanent maglev is possible under the effect of a combination of passive magnetic and nonmagnetic forces. In addition, a rotary left ventricular assist device (LVAD) with passive magnetic bearings has been developed. It is a radially driven impeller pump, having a rotor and a stator. The rotor consists of driven magnets and impeller; the motor coil and pump housing form the stator. Two passive magnetic bearings counteract the attractive force between motor coil iron core and rotor magnets; the rotor thereafter can be disaffiliated from the stator and become levitated under the action of passive magnetic and haemodynamic forces. Because of the pressure difference between the outlet and the inlet of the pump, there is a small flow passing through the gap of rotor and stator, and then entering the lower pressure area along the central hole of the rotor. This small flow comes to a full washout of all blood contacting surfaces in the motor. Moreover, a decreased Bernoulli force in the larger gap with faster flow produces a centring force that leads to stable levitation of the rotor. Resultantly, neither mechanical wear nor thrombosis will occur in the pump. The rotor position detection reveals that the precondition of levitation is a high rotating speed (over 3250 rpm) and a high flow rate (over 1 l min(-1)). Haemodynamic tests with porcine blood indicate that the device as a LVAD requires a rotating speed between 3500 and 4000 rpm for producing a blood flow of 4 - 6 l min(-1) against 100 mmHg mean pressure head. The egg-sized device has a weight of 200 g and an O.D. of 40 mm at its largest point.
He, Jianliang; Rote, Donald M.
1996-01-01
A stabilization and propulsion system comprising a series of loop-coils arranged in parallel rows wherein two rows combine to form one of two magnetic rails. Levitation and lateral stability are provided when the induced field in the magnetic rails interacts with the superconducting magnets mounted on the magnetic levitation vehicle. The loop-coils forming the magnetic rails have specified dimensions and a specified number of turns and by constructing differently these specifications, for one rail with respect to the other, the angle of tilt of the vehicle can be controlled during directional switching. Propulsion is provided by the interaction of a traveling magnetic wave associated with the coils forming the rails and the super conducting magnets on the vehicle.
He, J.; Rote, D.M.
1996-05-21
A stabilization and propulsion system are disclosed comprising a series of loop-coils arranged in parallel rows wherein two rows combine to form one of two magnetic rails. Levitation and lateral stability are provided when the induced field in the magnetic rails interacts with the superconducting magnets mounted on the magnetic levitation vehicle. The loop-coils forming the magnetic rails have specified dimensions and a specified number of turns and by constructing differently these specifications, for one rail with respect to the other, the angle of tilt of the vehicle can be controlled during directional switching. Propulsion is provided by the interaction of a traveling magnetic wave associated with the coils forming the rails and the superconducting magnets on the vehicle. 12 figs.
Electrodynamics in Giant Planet Atmospheres
NASA Astrophysics Data System (ADS)
Koskinen, T.; Yelle, R. V.; Lavvas, P.; Cho, J.
2014-12-01
The atmospheres of close-in extrasolar giant planets such as HD209458b are strongly ionized by the UV flux of their host stars. We show that photoionization on such planets creates a dayside ionosphere that extends from the thermosphere to the 100 mbar level. The resulting peak electron density near the 1 mbar level is higher than that encountered in any planetary ionosphere of the solar system, and the model conductivity is in fact comparable to the atmospheres of Sun-like stars. As a result, the momentum and energy balance in the upper atmosphere of HD209458b and similar planets can be strongly affected by ion drag and resistive heating arising from wind-driven electrodynamics. Despite much weaker ionization, electrodynamics is nevertheless also important on the giant planets of the solar system. We use a generic framework to constrain the conductivity regimes on close-in extrasolar planets, and compare the results with conductivites based on the same approach for Jupiter and Saturn. By using a generalized Ohm's law and assumed magnetic fields, we then demonstrate the basic effects of wind-driven ion drag in giant planet atmospheres. Our results show that ion drag is often significant in the upper atmosphere where it can also substantially alter the energy budget through resistive heating.
Electrodynamic studies of upper and lower atmospheric coupling
NASA Technical Reports Server (NTRS)
Chiu, Y. T.; Cornwall, J. M.; Edgar, B. C.; Schulz, M.; Sharp, L. R.
1981-01-01
Theoretical interprotations and data interpretations of electrodynamical studies in upper and lower atmosphere coupling are reported. The following topics are discussed: (1) magnetosphere/ionosphere/atmosphere coupling in auroral electrodynamics; (2) middle atmosphere electrodynamics; (3) thermosphere troposphere coupling; and (4) tropospheric electrodynamics. Understanding of the near Earth space environment shows the interrelationships between various components of the Earth's atmosphere.
Atmospheric electrodynamics in the U.S. - 1987-1990
NASA Technical Reports Server (NTRS)
Holzworth, R. H.
1991-01-01
Atmospheric electrodynamics research is summarized, focusing on three general areas: the ionosphere as a source for middle atmospheric electrodynamics, regional and global scale electrodynamics, and thunderstorms and lightning. New or improved instrumentation techniques which have furthered atmospheric electrodynamics research are also discussed.
Atmospheric electrodynamics in the U. S. - 1987-1990
Holzworth, R.H. )
1991-01-01
Atmospheric electrodynamics research is summarized, focusing on three general areas: the ionosphere as a source for middle atmospheric electrodynamics, regional and global scale electrodynamics, and thunderstorms and lightning. New or improved instrumentation techniques which have furthered atmospheric electrodynamics research are also discussed. 93 refs.
Report of the Electrodynamic Interactions Panel
NASA Technical Reports Server (NTRS)
Stone, N. H.; Taylor, R. S.; Benford, S.; Binsack, J. H.; Dobrowolny, M.; Finnegan, P.; Grossi, M. D.; Hudson, M.; Intriligator, D.; Kaminskas, R.
1985-01-01
A wide range of opportunities is provided by the electrodynamic tether to more fully understand the generation of waves in plasmas, the behavior of field aligned currents, the behavior of large body-space plasma interactions, and for process simulation, using the electrodynamic tether to study processes and phenomena relevant to solar system and astrophysics plasma physics. The electrodynamic tether offers a means of study and experimentation in space which will provide a rich yield in new scientific results and will enhance the understanding of space plasma physics. It also has promising technological applications (e.g., the generation of electrical power and thrust) which may be highly significant to future space operations.
Primordial magnetic fields and nonlinear electrodynamics
Kunze, Kerstin E.
2008-01-15
The creation of large scale magnetic fields is studied in an inflationary universe where electrodynamics is assumed to be nonlinear. After inflation ends electrodynamics becomes linear and thus the description of reheating and the subsequent radiation dominated stage are unaltered. The nonlinear regime of electrodynamics is described by Lagrangians having a power-law dependence on one of the invariants of the electromagnetic field. It is found that there is a range of parameters for which primordial magnetic fields of cosmologically interesting strengths can be created.
Fluctuational electrodynamics of hyperbolic metamaterials
Guo, Yu; Jacob, Zubin
2014-06-21
We give a detailed account of equilibrium and non-equilibrium fluctuational electrodynamics of hyperbolic metamaterials. We show the unifying aspects of two different approaches; one utilizes the second kind of fluctuation dissipation theorem and the other makes use of the scattering method. We analyze the near-field of hyperbolic media at finite temperatures and show that the lack of spatial coherence can be attributed to the multi-modal nature of super-Planckian thermal emission. We also adopt the analysis to phonon-polaritonic super-lattice metamaterials and describe the regimes suitable for experimental verification of our predicted effects. The results reveal that far-field thermal emission spectra are dominated by epsilon-near-zero and epsilon-near-pole responses as expected from Kirchoff's laws. Our work should aid both theorists and experimentalists to study complex media and engineer equilibrium and non-equilibrium fluctuations for applications in thermal photonics.
Superconducting magnet and on-board refrigeration system on Japanese MAGLEV vehicle
Tsuchishima, H.; Herai, T. )
1991-03-01
This paper reports on a superconducting magnet and on-board refrigeration system on Japanese MAGLEV vehicles. Running tests on the Miyazaki test track are repeatedly carried out at speeds over 300 km/h using the MAGLEV vehicle, MLU002. The development of the MAGLEV system for the new test line has already started, and a new superconducting magnet for it has been manufactured. An on-board refrigerator is installed in the superconducting magnet to keep the liquid helium temperature without the loss of liquid helium. The helium gas produced when energizing or de-energizing the magnet is stored in on-board gas helium tanks temporarily. The on-board refrigerator is connected directly to the liquid helium tank of the magnet.
Field measurements and analyses of environmental vibrations induced by high-speed Maglev.
Li, Guo-Qiang; Wang, Zhi-Lu; Chen, Suwen; Xu, You-Lin
2016-10-15
Maglev, offers competitive journey-times compared to the railway and subway systems in markets for which distance between the stations is 100-1600km owing to its high acceleration and speed; however, such systems may have excessive vibration. Field measurements of Maglev train-induced vibrations were therefore performed on the world's first commercial Maglev line in Shanghai, China. Seven test sections along the line were selected according to the operating conditions, covering speeds from 150 to 430km/h. Acceleration responses of bridge pier and nearby ground were measured in three directions and analyzed in both the time and frequency domain. The effects of Maglev train speed on vibrations of the bridge pier and ground were studied in terms of their peak accelerations. Attenuation of ground vibration was investigated up to 30m from the track centerline. Effects of guideway configuration were also analyzed based on the measurements through two different test sections with same train speed of 300km/h. The results showed that peak accelerations exhibited a strong correlation with both train speed and distance off the track. Guideway configuration had a significant effect on transverse vibration, but a weak impact on vertical and longitudinal vibrations of both bridge pier and ground. Statistics indicated that, contrary to the commonly accepted theory and experience, vertical vibration is not always dominant: transverse and longitudinal vibrations should also be considered, particularly near turns in the track. Moreover, measurements of ground vibration induced by traditional high-speed railway train were carried out with the same testing devices in Bengbu in the Anhui Province. Results showed that the Maglev train generates significantly different vibration signatures as compared to the traditional high-speed train. The results obtained from this paper can provide good insights on the impact of Maglev system on the urban environment and the quality of human life
Symmetries of field equations of axion electrodynamics
NASA Astrophysics Data System (ADS)
Nikitin, A. G.; Kuriksha, Oksana
2012-07-01
The group classification of models of axion electrodynamics with arbitrary self-interaction of axionic field is carried out. It is shown that extensions of the basic Poincaré invariance of these models appear only for constant and exponential interactions. The related conservation laws are discussed. The maximal continuous symmetries of the 3d Chern-Simons electrodynamics and Carroll-Field-Jackiw electrodynamics are presented. Using the Inönü-Wigner contraction the nonrelativistic limit of equations of axion electrodynamics is found. Exact solutions for the electromagnetic and axion fields are discussed including those which describe propagation with group velocities faster than the speed of light. However these solutions are causal since the corresponding energy velocities are subluminal.
Disposable MagLev centrifugal blood pump utilizing a cone-shaped impeller.
Hijikata, Wataru; Sobajima, Hideo; Shinshi, Tadahiko; Nagamine, Yasuyuki; Wada, Suguru; Takatani, Setsuo; Shimokohbe, Akira
2010-08-01
To enhance the durability and reduce the blood trauma of a conventional blood pump with a cone-shaped impeller, a magnetically levitated (MagLev) technology has been applied to the BioPump BPX-80 (Medtronic Biomedicus, Inc., Minneapolis, MN, USA), whose impeller is supported by a mechanical bearing. The MagLev BioPump (MagLev BP), which we have developed, has a cone-shaped impeller, the same as that used in the BPX-80. The suspension and driving system, which is comprised of two degrees of freedom, radial-controlled magnetic bearing, and a simply structured magnetic coupling, eliminates any physical contact between the impeller and the housing. To reduce both oscillation of the impeller and current in the coils, the magnetic bearing system utilizes repetitive and zero-power compensators. In this article, we present the design of the MagLev mechanism, measure the levitational accuracy of the impeller and pressure-flow curves (head-quantity [HQ] characteristics), and describe in vitro experiments designed to measure hemolysis. For the flow-induced hemolysis of the initial design to be reduced, the blood damage index was estimated by using computational fluid dynamics (CFD) analysis. Stable rotation of the impeller in a prototype MagLev BP from 0 to 2750 rpm was obtained, yielding a flow rate of 5 L/min against a head pressure in excess of 250 mm Hg. Because the impeller of the prototype MagLev BP is levitated without contact, the normalized index of hemolysis was 10% less than the equivalent value with the BPX-80. The results of the CFD analysis showed that the shape of the outlet and the width of the fluid clearances have a large effect on blood damage. The prototype MagLev BP satisfied the required HQ characteristics (5 L/min, 250 mm Hg) for extracorporeal circulation support with stable levitation of the impeller and showed an acceptable level of hemolysis. The simulation results of the CFD analysis indicated the possibility of further reducing the blood damage of
Lie algebras of classical and stochastic electrodynamics
NASA Astrophysics Data System (ADS)
Neto, J. J. Soares; Vianna, J. D. M.
1994-03-01
The Lie algebras associated with infinitesimal symmetry transformations of third-order differential equations of interest to classical electrodynamics and stochastic electrodynamics have been obtained. The structure constants for a general case are presented and the Lie algebra for each particular application is easily achieved. By the method used here it is not necessary to know the explicit expressions of the infinitesimal generators in order to determine the structure constants of the Lie algebra.
Design Optimization for a Maglev System Employing Flux Eliminating Coils
NASA Technical Reports Server (NTRS)
Davey, Kent R.
1996-01-01
Flux eliminating coils have received no little attention over the past thirty years as an alternative for realizing lift in a MAGLEV system. When the magnets on board the vehicle are displaced from the equilibrium or null flux point of these coils, they induce current in those coils which act to restore the coil to its null flux or centerline position. The question being addressed in this paper is that of how to choose the best coil for a given system. What appears at first glance to be an innocent question is in fact one that is actually quite involved, encompassing both the global economics and physics of the system. The real key in analyzing that question is to derive an optimization index or functional which represents the cost of the system subject to constraints, the primary constraint being that the vehicle lift itself at a certain threshold speed. Outlined in this paper is one scenario for realizing a total system design which uses sequential quadratic programming techniques.
Middle Atmosphere Electrodynamics (MAE). Middle atmospheric electrodynamics during MAP
NASA Technical Reports Server (NTRS)
Goldberg, R. A.
1989-01-01
The recent revival and strong motivation for research in middle atmospheric electrodynamics can be attributed, in large part, to the discovery of large (V/m) electric fields within the lower mesosphere during the decade prior to MAP. Subsequent rocket soundings appeared to verify the preliminary findings. During the MAP era, more sophisticated techniques have been employed to obtain measurements which respond positively to criticisms of earlier results, and which provide more insight regarding the character of the fields. The occurrence of mesospheric V/m electric fields now seems to require the presence of aerosols, of local winds and related dynamics, and of an atmospheric electrical conductivity less than 10(-10)S/m. Furthermore, new theoretical ideas describing the origin of the V/m fields are consistent with the measurements. The current status of results regarding V/m fields in the middle atmosphere is reviewed in light of the more widely accepted electric field structure for this region from rocket, balloon and modeling results.
Global electrodynamics from superpressure balloons
NASA Astrophysics Data System (ADS)
Holzworth, R. H.; Hu, H.
1995-08-01
Electric field and conductivity measurements in the stratosphere between November 1992 and March 1993 have been made using superpressure balloons in the southern hemisphere. Over 400 payload-days of data have been made during a record setting experiment called ELBBO (Extended Life Balloon Borne Observatories). This experiment resulted in 4 flights aloft simultaneously for over 2 months including one flight which lasted over 4 months. Electrodynamical coupling between the atmosphere and ionosphere is studied using the measured electric fields, and a simple empirical model of the stratospheric conductivity. Altitude profiles of conductivity have been obtained from several superpressure balloon flights using the large end-of-flight altitude swings on the last few days of each flight (as the balloon begins to loose superpressure). Coupling between the fields and atmospheric inertial waves has been observed. Effects and dynamics of the global circuit suggest that standard models are missing significant phenomena. Large scale ionospheric convection activity has been studied from the polar cap to the middle latitudes. Cusp latitude fields have been continuously measured for many days in a row.
Nanofriction in Cavity Quantum Electrodynamics
NASA Astrophysics Data System (ADS)
Fogarty, T.; Cormick, C.; Landa, H.; Stojanović, Vladimir M.; Demler, E.; Morigi, Giovanna
2015-12-01
The dynamics of cold trapped ions in a high-finesse resonator results from the interplay between the long-range Coulomb repulsion and the cavity-induced interactions. The latter are due to multiple scatterings of laser photons inside the cavity and become relevant when the laser pump is sufficiently strong to overcome photon decay. We study the stationary states of ions coupled with a mode of a standing-wave cavity as a function of the cavity and laser parameters, when the typical length scales of the two self-organizing processes, Coulomb crystallization and photon-mediated interactions, are incommensurate. The dynamics are frustrated and in specific limiting cases can be cast in terms of the Frenkel-Kontorova model, which reproduces features of friction in one dimension. We numerically recover the sliding and pinned phases. For strong cavity nonlinearities, they are in general separated by bistable regions where superlubric and stick-slip dynamics coexist. The cavity, moreover, acts as a thermal reservoir and can cool the chain vibrations to temperatures controlled by the cavity parameters and by the ions' phase. These features are imprinted in the radiation emitted by the cavity, which is readily measurable in state-of-the-art setups of cavity quantum electrodynamics.
Optimal Electrodynamic Tether Phasing Maneuvers
NASA Technical Reports Server (NTRS)
Bitzer, Matthew S.; Hall, Christopher D.
2007-01-01
We study the minimum-time orbit phasing maneuver problem for a constant-current electrodynamic tether (EDT). The EDT is assumed to be a point mass and the electromagnetic forces acting on the tether are always perpendicular to the local magnetic field. After deriving and non-dimensionalizing the equations of motion, the only input parameters become current and the phase angle. Solution examples, including initial Lagrange costates, time of flight, thrust plots, and thrust angle profiles, are given for a wide range of current magnitudes and phase angles. The two-dimensional cases presented use a non-tilted magnetic dipole model, and the solutions are compared to existing literature. We are able to compare similar trajectories for a constant thrust phasing maneuver and we find that the time of flight is longer for the constant thrust case with similar initial thrust values and phase angles. Full three-dimensional solutions, which use a titled magnetic dipole model, are also analyzed for orbits with small inclinations.
Nanofriction in Cavity Quantum Electrodynamics.
Fogarty, T; Cormick, C; Landa, H; Stojanović, Vladimir M; Demler, E; Morigi, Giovanna
2015-12-04
The dynamics of cold trapped ions in a high-finesse resonator results from the interplay between the long-range Coulomb repulsion and the cavity-induced interactions. The latter are due to multiple scatterings of laser photons inside the cavity and become relevant when the laser pump is sufficiently strong to overcome photon decay. We study the stationary states of ions coupled with a mode of a standing-wave cavity as a function of the cavity and laser parameters, when the typical length scales of the two self-organizing processes, Coulomb crystallization and photon-mediated interactions, are incommensurate. The dynamics are frustrated and in specific limiting cases can be cast in terms of the Frenkel-Kontorova model, which reproduces features of friction in one dimension. We numerically recover the sliding and pinned phases. For strong cavity nonlinearities, they are in general separated by bistable regions where superlubric and stick-slip dynamics coexist. The cavity, moreover, acts as a thermal reservoir and can cool the chain vibrations to temperatures controlled by the cavity parameters and by the ions' phase. These features are imprinted in the radiation emitted by the cavity, which is readily measurable in state-of-the-art setups of cavity quantum electrodynamics.
Nonlocal electrodynamics in Weyl semimetals
NASA Astrophysics Data System (ADS)
Rosenstein, B.; Kao, H. C.; Lewkowicz, M.
2017-02-01
Recently synthesized three-dimensional materials with Dirac spectrum exhibit peculiar electric transport qualitatively different from its two-dimensional analog, graphene. By neglecting impurity scattering, the real part of the conductivity is strongly frequency dependent, while the imaginary part is nonzero unlike in undoped, clean graphene. The Coulomb interaction between electrons is unscreened as in a dielectric and hence is long range. We demonstrate that the interaction correction renders the electrodynamics nonlocal on a mesoscopic scale. The longitudinal conductivity σL and the transverse conductivity σT are different in the long-wavelength limit and consequently the standard local Ohm's law description does not apply. This leads to several remarkable effects in optical response. The p -polarized light generates in these materials bulk plasmons as well as the transversal waves. At a specific frequency the two modes coincide, a phenomenon impossible in a local medium. For any frequency there is a Brewster angle where total absorption occurs, turning the Weyl semimetals opaque. The effect of the surface, including the Fermi arcs, is discussed.
Nonlinear electrodynamics and CMB polarization
Cuesta, Herman J. Mosquera; Lambiase, G. E-mail: lambiase@sa.infn.it
2011-03-01
Recently WMAP and BOOMERanG experiments have set stringent constraints on the polarization angle of photons propagating in an expanding universe: Δα = (−2.4±1.9)°. The polarization of the Cosmic Microwave Background radiation (CMB) is reviewed in the context of nonlinear electrodynamics (NLED). We compute the polarization angle of photons propagating in a cosmological background with planar symmetry. For this purpose, we use the Pagels-Tomboulis (PT) Lagrangian density describing NLED, which has the form L ∼ (X/Λ{sup 4}){sup δ−1} X, where X = ¼F{sub αβ}F{sup αβ}, and δ the parameter featuring the non-Maxwellian character of the PT nonlinear description of the electromagnetic interaction. After looking at the polarization components in the plane orthogonal to the (x)-direction of propagation of the CMB photons, the polarization angle is defined in terms of the eccentricity of the universe, a geometrical property whose evolution on cosmic time (from the last scattering surface to the present) is constrained by the strength of magnetic fields over extragalactic distances.
Chern-Simons quantum electrodynamics
NASA Astrophysics Data System (ADS)
Clancy, John Paul
The first two chapters provide background information for the dissertation. In the first chapter, a brief history of Chern-Simons quantum field theories is given and motivation for studying these models is given by examining their physical properties and their mathematical difficulties. The second chapter gives a brief overview of quantum field theory, by presenting the Garding-Wightman formalism and the necessary modifications for studying quantum gauge field theories. Finally, the mathematical tools used in the following chapters are described. In the third chapter, Chern-Simons Quantum Electrodynamics is presented and its main features are developed. The gauge field is canonically quantized and the underlying indefinite metric is identified. Next, the physical subspace is characterized by functions that are analytic in harmonic oscillator coordinates. This property is used to show an equivalence between the Gauss vectors, gauge invariance, and positivity with respect to the indefinite metric. The fourth chapter presents the Euclidean formulation of this model, where the covariance for the free gauge field is calculated, and shown to generate a complex, Gaussian measure describing a real, random process. Next, a path-space formula on the Gauss vectors is developed, from which it follows that the physical vectors satisfy the Osterwalder-Schrader positivity requirement.
Global electrodynamics from superpressure balloons
NASA Technical Reports Server (NTRS)
Holzworth, R. H.; Hu, H.
1995-01-01
Electric field and conductivity measurements in the stratosphere between November 1992 and March 1993 have been made using superpressure balloons in the southern hemisphere. Over 400 payload-days of data have been made during a record setting experiment called ELBBO (Extended Life Balloon Borne Observatories). This experiment resulted in 4 flights aloft simultaneously for over 2 months including one flight which lasted over 4 months. Electrodynamical coupling between the atmosphere and ionosphere is studied using the measured electric fields, and a simple empirical model of the stratospheric conductivity. Altitude profiles of conductivity have been obtained from several superpressure balloon flights using the large end-of-flight altitude swings on the last few days of each flight (as the balloon begins to loose superpressure). Coupling between the fields and atmospheric inertial waves has been observed. Effects and dynamics of the global circuit suggest that standard models are missing significant phenomena. Large scale ionospheric convection activity has been studied from the polar cap to the middle latitudes. Cusp latitude fields have been continuously measured for many days in a row.
Performance analysis of the combined EDS maglev propulsion, levitation, and guidance system
He, J.L.; Coffey, H.T.; Rote, D.M.
1993-10-01
An analysis of the Japanese maglev system which uses only one set of coils in the guideway for combined levitation, propulsion, and guidance functions is presented in this paper. This preliminary study, using the dynamic circuit approach, indicates that the system is very promising.
Regardless-of-Speed Superconducting LSM Controlled-Repulsive MAGLEV Vehicle
NASA Technical Reports Server (NTRS)
Yoshida, Kinjiro; Egashira, Tatsuya; Hirai, Ryuichi
1996-01-01
This paper proposes a new repulsive Maglev vehicle which a superconducting linear synchronous motor (LSM) can levitate and propel simultaneously, independently of the vehicle speeds. The combined levitation and propulsion control is carried out by controlling mechanical-load angle and armature-current. Dynamic simulations show successful operations with good ride-quality by using a compact control method proposed here.
49 CFR 268.5 - Federal funding sources for the Maglev Deployment Program.
Code of Federal Regulations, 2012 CFR
2012-10-01
... 49 Transportation 4 2012-10-01 2012-10-01 false Federal funding sources for the Maglev Deployment Program. 268.5 Section 268.5 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION MAGNETIC LEVITATION...
49 CFR 268.5 - Federal funding sources for the Maglev Deployment Program.
Code of Federal Regulations, 2013 CFR
2013-10-01
... 49 Transportation 4 2013-10-01 2013-10-01 false Federal funding sources for the Maglev Deployment Program. 268.5 Section 268.5 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION MAGNETIC LEVITATION...
49 CFR 268.5 - Federal funding sources for the Maglev Deployment Program.
Code of Federal Regulations, 2014 CFR
2014-10-01
... 49 Transportation 4 2014-10-01 2014-10-01 false Federal funding sources for the Maglev Deployment Program. 268.5 Section 268.5 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION MAGNETIC LEVITATION...
49 CFR 268.3 - Different phases of the Maglev Deployment Program.
Code of Federal Regulations, 2012 CFR
2012-10-01
... 49 Transportation 4 2012-10-01 2012-10-01 false Different phases of the Maglev Deployment Program. 268.3 Section 268.3 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION MAGNETIC LEVITATION TRANSPORTATION...
49 CFR 268.5 - Federal funding sources for the Maglev Deployment Program.
Code of Federal Regulations, 2011 CFR
2011-10-01
... 49 Transportation 4 2011-10-01 2011-10-01 false Federal funding sources for the Maglev Deployment Program. 268.5 Section 268.5 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION MAGNETIC LEVITATION...
Development of a Mathematics, Science, and Technology Education Integrated Program for a Maglev
ERIC Educational Resources Information Center
Park, Hyoung Seo
2006-01-01
The purpose of the study was to develop an MST Integrated Program for making a Maglev hands-on activity for higher elementary school students in Korea. In this MST Integrated Program, students will apply Mathematics, Science, and Technology principles and concepts to the design, construction, and evaluation of a magnetically levitated vehicle. The…
49 CFR 268.3 - Different phases of the Maglev Deployment Program.
Code of Federal Regulations, 2013 CFR
2013-10-01
... include demand and revenue analyses, project specification, cost estimates, scheduling, financial studies, a system safety plan (including supporting analysis), and other information in support of the... preconstruction planning financial assistance awarded under this part to perform Phase II of the Maglev...
49 CFR 268.3 - Different phases of the Maglev Deployment Program.
Code of Federal Regulations, 2014 CFR
2014-10-01
... include demand and revenue analyses, project specification, cost estimates, scheduling, financial studies, a system safety plan (including supporting analysis), and other information in support of the... preconstruction planning financial assistance awarded under this part to perform Phase II of the Maglev...
NASA Astrophysics Data System (ADS)
Chung, Y. D.; Lee, C. Y.; Jang, J. Y.; Yoon, Y. S.; Ko, T. K.
2011-11-01
We have been constructed a proto-type electromagnetic suspension (EMS) based maglev vehicle system. The maglev concept utilizes magnetic forces for noncontact suspension, guidance and propulsion. The suspension system with high temperature superconducting (HTS) hybrid electromagnet (EM) is composed of HTS coils and normal coils, which consume little power to keep large suspension gap. The magnetic forces realize to guide the vehicle, propel the vehicle along the guide-way and assist in braking action. The proto-type EMS-based Maglev model is designed to keep the suspension gap of 20 mm. This paper presents the theoretical analysis of the maglev vehicle based on the EMS model to obtain the designing parameters for levitation and propulsion forces. The magnetic field distributions of the electromagnetic forces with hybrid EM and propulsion stator coils are analyzed based on three dimension (3D) finite element method (FEM) analysis. From the simulation results, appropriately design parameters of the suspension, guidance and propulsion were obtained.
NASA Technical Reports Server (NTRS)
Luerken, Reinhard F.
1994-01-01
The Transrapid maglev technology is at the threshold of commercial deployment and technologically all prerequisites for the successful operation of the system in public service are given. In post unification Germany the domestic maglev technology is envisioned to be applied in the Berlin-Hamburg project. At present, a public-private funding concept is being prepared and the lengthy planning process is about to be initiated. In the USA the AMG has presented a program to Americanize the technology and to make it available for commercial use in the U.S. in the very near future. The paramount features of this program are to generate economic development, provide a basis for transportation technology development, create opportunities for U.S. industry, improve the U.S. transportation infrastructure, and improve the environment and traveler safety. Maglev is ready for the U.S.; is the U.S. ready for maglev?
Renormalizable Electrodynamics of Scalar and Vector Mesons. Part II
DOE R&D Accomplishments Database
Salam, Abdus; Delbourgo, Robert
1964-01-01
The "gauge" technique" for solving theories introduced in an earlier paper is applied to scalar and vector electrodynamics. It is shown that for scalar electrodynamics, there is no {lambda}φ*2φ2 infinity in the theory, while with conventional subtractions vector electrodynamics is completely finite. The essential ideas of the gauge technique are explained in section 3, and a preliminary set of rules for finite computation in vector electrodynamics is set out in Eqs. (7.28) - (7.34).
Quantum electrodynamics and fundamental constants
NASA Astrophysics Data System (ADS)
Wundt, Benedikt Johannes Wilhelm
The unprecedented precision achieved both in the experimental measurements as well as in the theoretical description of atomic bound states make them an ideal study object for fundamental physics and the determination of fundamental constants. This requires a careful study of the effects from quantum electrodynamics (QED) on the interaction between the electron and the nucleus. The two theoretical approaches for the evaluation of QED corrections are presented and discussed. Due to the presence of two energy scales from the binding potential and the radiation field, an overlapping parameter has to be used in both approaches in order to separate the energy scales. The different choices for the overlapping parameter in the two methods are further illustrated in a model example. With the nonrelativistic theory, relativistic corrections in order ( Zalpha)2 to the two-photon decay rate of ionic states are calculated, as well as the leading radiative corrections of alpha( Zalpha)2ln[(Zalpha)-2 ]. It is shown that the corrections is gauge-invariant under a "hybrid" gauge transformation between Coulomb and Yennie gauge. Furthermore, QED corrections for Rydberg states in one-electron ions are investigated. The smallness of the corrections and the absence of nuclear size corrections enable very accurate theoretical predictions. Measuring transition frequencies and comparing them to the theoretical predictions, QED theory can be tested more precisely. In turn, this could yield a more accurate value for the Rydberg constant. Using a transition in a nucleus with a well determined mass, acting as a reference, a comparison to transition in other nuclei can even allow to determined nuclear masses. Finally, in order to avoid an additional uncertainty in nuclei with non zero nuclear spin, QED self-energy corrections to the hyperfine structure up to order alpha(Zalpha)2Delta EHFS are determined for highly excited Rydberg states.
Stochastic Electrodynamics: A Road to Quantum Gravity
NASA Astrophysics Data System (ADS)
Lavenda, B. H.
A formal analogy exists between electrodynamic and gravitational phenomena: the Coulomb potential is analogous to the Newton potential and both possess fine structure constants. There are no singularities in Nature; uncertainties in the measurement of small distances are accounted for by an extreme value probability distribution for smallest value of the radial coordinate. Quantum electrodynamic phenomena can simply be accounted for by a stochastic generalization of the Bohr model which we will then carry over to the quantum Kepler model. Both in quantum electrodynamics and gravitation all characteristic scales are related by simple powers of the fine structure constants. A new uncertainty relation between momentum and inverse separation between particles is derived. Electromagnetic and gravitational radiation phenomena are analyzed and compared.
Quantum gravitational contributions to quantum electrodynamics.
Toms, David J
2010-11-04
Quantum electrodynamics describes the interactions of electrons and photons. Electric charge (the gauge coupling constant) is energy dependent, and there is a previous claim that charge is affected by gravity (described by general relativity) with the implication that the charge is reduced at high energies. However, that claim has been very controversial and the matter has not been settled. Here I report an analysis (free from the earlier controversies) demonstrating that quantum gravity corrections to quantum electrodynamics have a quadratic energy dependence that result in the electric charge vanishing at high energies, a result known as asymptotic freedom.
The tethered satellite electrodynamics experiment project
NASA Technical Reports Server (NTRS)
Price, John M.
1988-01-01
NASA and Italy's PSN have undertaken the Tethered Satellite Electrodynamics Experiment, in which two tethered bodies will be equipped with data-collecting scientific instruments, as the first stage of the development of the Tethered Satellite System that can be deployed by the Space Shuttle. The experiment will give attention to the electromagnetic interaction between the satellite/tether/orbiter system and the ambient space plasma, and should demonstrate the operation of both satellite- and Shuttle-borne electrodynamic instruments with a conductive tether.
Polymeric Coatings for Electrodynamic Tethers
NASA Technical Reports Server (NTRS)
Vaughn, Jason A.; Kamenetzky, Rachel R.; Finckenor, Miria M.; Schuler, Peter
2000-01-01
Two polymeric coatings have been developed for the Propulsive Small Expendable Deployer System (ProSEDS) mission. ProSEDS is designed to provide an on-orbit demonstration of the electrodynamic propulsion capabilities of tethers in space. The ProSEDS experiment will be a secondary payload on a Delta II unmanned expendable booster scheduled for launch in August 2000. A 5-km conductive tether is attached to the Delta 11 second stage and collects current from the low Earth orbit (LEO) plasma to facilitate de-orbit of the spent stage. The conductive tether is attached to a 10-km non-conductive tether, the other end of which is attached to an endmass containing several scientific instruments. A bare metal tether would have the best conductivity but thermal concerns preclude this design. A conductive polymer developed by Triton Systems has been optimized for conductivity and thermo-optical properties. The current design for the ProSEDS conductive tether is seven strands of 28 AWG aluminum wire individually coated with 8.7 micrometers (0.35 mil) of an atomic oxygen-resistant conductive polymer composed of a mixture of 87% Clear Oxygen-Resistant polymer (COR) and 13% polyanaline (PANi), wrapped around a braided Kevlar (TM) 49 core. Extensive testing has been performed at the Marshall Space Flight Center (MSFC) to qualify this material for flight on ProSEDS. Atomic oxygen exposure was performed, with solar absorptance and infrared emittance measured before and after exposure. Conductivity was measured before and after atomic oxygen exposure. High voltage tests, up to 1500 V, of the current collecting ability of the COR/PANi have been completed. Approximately 160 meters of the conductive tether closest to the Delta 11 second stage is insulated to prevent any electron reconnection to the tether from the plasma contactor. The insulation is composed of polyimide overcoated with TOR-BP, another polymeric coating developed by Triton for this mission. TOR-BP acts as both insulator
Electrodynamics in One Dimension: Radiation and Reflection
ERIC Educational Resources Information Center
Asti, G.; Coisson, R.
2011-01-01
Problems involving polarized plane waves and currents on sheets perpendicular to the wavevector involve only one component of the fields, so it is possible to discuss electrodynamics in one dimension. Taking for simplicity linearly polarized sinusoidal waves, we can derive the field emitted by currents (analogous to dipole radiation in three…
Students' Difficulties with Vector Calculus in Electrodynamics
ERIC Educational Resources Information Center
Bollen, Laurens; van Kampen, Paul; De Cock, Mieke
2015-01-01
Understanding Maxwell's equations in differential form is of great importance when studying the electrodynamic phenomena discussed in advanced electromagnetism courses. It is therefore necessary that students master the use of vector calculus in physical situations. In this light we investigated the difficulties second year students at KU Leuven…
Quantum electrodynamics with complex fermion mass
McKellar, B.J.H. . School of Physics); Wu, D.D. . School of Physics Academia Sinica, Beijing, BJ . Inst. of High Energy Physics Superconducting Super Collider Lab., Dallas, TX )
1991-08-01
The quantum electrodynamics (QED) with a complex fermion mass -- that is, a fermion mass with a chiral phase -- is restudied, together with its chirally rotated version. We show how fake electric dipole moment can be obtained and how to avoid it. 10 refs.
Strong field electrodynamics of a thin foil
Bulanov, Sergei V.; Esirkepov, Timur Zh.; Kando, Masaki; Bulanov, Stepan S.; Rykovanov, Sergey G.; Pegoraro, Francesco
2013-12-15
Exact solutions describing the nonlinear electrodynamics of a thin double layer foil are presented. These solutions correspond to a broad range of problems of interest for the interaction of high intensity laser pulses with overdense plasmas, such as frequency upshifting, high order harmonic generation, and high energy ion acceleration.
Linear Response Laws and Causality in Electrodynamics
ERIC Educational Resources Information Center
Yuffa, Alex J.; Scales, John A.
2012-01-01
Linear response laws and causality (the effect cannot precede the cause) are of fundamental importance in physics. In the context of classical electrodynamics, students often have a difficult time grasping these concepts because the physics is obscured by the intermingling of the time and frequency domains. In this paper, we analyse the linear…
Nonlinear quantum electrodynamics in vacuum and plasmas
Brodin, Gert; Lundin, Joakim; Marklund, Mattias
2010-12-14
We consider high field physics due to quantum electrodynamics, in particular those that can be studied in the next generation of laser facilities. Effective field theories based on the Euler-Heisenberg Lagrangian are briefly reviewed, and examples involving plasma- and vacuum physics are given.
Quantum Hall effect in quantum electrodynamics
Penin, Alexander A.
2009-03-15
We consider the quantum Hall effect in quantum electrodynamics and find a deviation from the quantum-mechanical prediction for the Hall conductivity due to radiative antiscreening of electric charge in an external magnetic field. A weak dependence of the universal von Klitzing constant on the magnetic field strength, which can possibly be observed in a dedicated experiment, is predicted.
Lamb Shift in Nonrelativistic Quantum Electrodynamics.
ERIC Educational Resources Information Center
Grotch, Howard
1981-01-01
The bound electron self-energy or Lamb shift is calculated in nonrelativistic quantum electrodynamics. Retardation is retained and also an interaction previously dropped in other nonrelativistic approaches is kept. Results are finite without introducing a cutoff and lead to a Lamb shift in hydrogen of 1030.9 MHz. (Author/JN)
Electrodynamic Tethers for Novel LEO Missions
NASA Technical Reports Server (NTRS)
Kantner, Michael; Hoyt, Robert; Scardera, Michael; Johnson, Charles
2011-01-01
The exponential increase of launch system size - and cost - with deltaV makes missions requiring large total impulse cost prohibitive. Northrop Grumman and partners have matured a fundamentally different method for generating propulsion using electrodynamic tethers (EDTs) that escapes the limitations of the rocket equation. With essentially unlimited delta V, we can perform new classes of missions that are currently unaffordable or unfeasible.
Strong field electrodynamics of a thin foil
NASA Astrophysics Data System (ADS)
Bulanov, S. S.; Bulanov, S. V.; Esirkepov, T. Zh.; Kando, M.; Rykovanov, S.; Pegoraro, F.; Schroeder, C. B.; Esarey, E.; Leemans, W. P.
2017-03-01
A new one-dimensional analytical model of a thin double layer foil interaction with a laser pulse is presented. It is based on one-dimensional electrodynamics. This model can be used for the study of high intensity laser pulse interactions with overdense plasmas, leading to frequency upshifting, high order harmonic generation, and ion acceleration in different regimes.
Dual keel Space Station payload pointing system design and analysis feasibility study
NASA Technical Reports Server (NTRS)
Smagala, Tom; Class, Brian F.; Bauer, Frank H.; Lebair, Deborah A.
1988-01-01
A Space Station attached Payload Pointing System (PPS) has been designed and analyzed. The PPS is responsible for maintaining fixed payload pointing in the presence of disturbance applied to the Space Station. The payload considered in this analysis is the Solar Optical Telescope. System performance is evaluated via digital time simulations by applying various disturbance forces to the Space Station. The PPS meets the Space Station articulated pointing requirement for all disturbances except Shuttle docking and some centrifuge cases.
Theory and experiment research for ultra-low frequency maglev vibration sensor.
Zheng, Dezhi; Liu, Yixuan; Guo, Zhanshe; Zhao, Xiaomeng; Fan, Shangchun
2015-10-01
A new maglev sensor is proposed to measure ultra-low frequency (ULF) vibration, which uses hybrid-magnet levitation structure with electromagnets and permanent magnets as the supporting component, rather than the conventional spring structure of magnetoelectric vibration sensor. Since the lower measurement limit needs to be reduced, the equivalent bearing stiffness coefficient and the equivalent damping coefficient are adjusted by the sensitivity unit structure of the sensor and the closed-loop control system, which realizes both the closed-loop control and the solving algorithms. A simple sensor experimental platform is then assembled based on a digital hardware system, and experimental results demonstrate that the lower measurement limit of the sensor is increased to 0.2 Hz under these experimental conditions, indicating promising results of the maglev sensor for ULF vibration measurements.
Theory and experiment research for ultra-low frequency maglev vibration sensor
NASA Astrophysics Data System (ADS)
Zheng, Dezhi; Liu, Yixuan; Guo, Zhanshe; Zhao, Xiaomeng; Fan, Shangchun
2015-10-01
A new maglev sensor is proposed to measure ultra-low frequency (ULF) vibration, which uses hybrid-magnet levitation structure with electromagnets and permanent magnets as the supporting component, rather than the conventional spring structure of magnetoelectric vibration sensor. Since the lower measurement limit needs to be reduced, the equivalent bearing stiffness coefficient and the equivalent damping coefficient are adjusted by the sensitivity unit structure of the sensor and the closed-loop control system, which realizes both the closed-loop control and the solving algorithms. A simple sensor experimental platform is then assembled based on a digital hardware system, and experimental results demonstrate that the lower measurement limit of the sensor is increased to 0.2 Hz under these experimental conditions, indicating promising results of the maglev sensor for ULF vibration measurements.
Theory and experiment research for ultra-low frequency maglev vibration sensor
Zheng, Dezhi; Liu, Yixuan Guo, Zhanshe; Fan, Shangchun; Zhao, Xiaomeng
2015-10-15
A new maglev sensor is proposed to measure ultra-low frequency (ULF) vibration, which uses hybrid-magnet levitation structure with electromagnets and permanent magnets as the supporting component, rather than the conventional spring structure of magnetoelectric vibration sensor. Since the lower measurement limit needs to be reduced, the equivalent bearing stiffness coefficient and the equivalent damping coefficient are adjusted by the sensitivity unit structure of the sensor and the closed-loop control system, which realizes both the closed-loop control and the solving algorithms. A simple sensor experimental platform is then assembled based on a digital hardware system, and experimental results demonstrate that the lower measurement limit of the sensor is increased to 0.2 Hz under these experimental conditions, indicating promising results of the maglev sensor for ULF vibration measurements.
Design and analysis of an electromagnetic turnout for the superconducting Maglev system
NASA Astrophysics Data System (ADS)
Li, Y. J.; Dai, Q.; Zhang, Y.; Wang, H.; Chen, Z.; Sun, R. X.; Zheng, J.; Deng, C. Y.; Deng, Z. G.
2016-09-01
Turnout is a crucial track junction device of the ground rail transportation system. For high temperature superconducting (HTS) Maglev system, the permanent magnet guideway (PMG) makes the strong magnetic force existing between rail segments, which may cause moving difficulties and increase the operation cost when switching a PMG. In this paper, a non-mechanical 'Y' shaped Halbach-type electromagnetic turnout was proposed. By replacing the PMs with electromagnets, the turnout can guide the maglev vehicle running into another PMG by simply controlling the current direction of electromagnets. The material and structure parameters of the electromagnets were optimized by simulation. The results show that the optimized electromagnet can keep the magnetic field above it as strong as the PMs', meanwhile feasible for design and manufacture. This work provides valuable references for the future design in non-mechanical PMG turnout.
Optimization of levitation and guidance forces in a superconducting Maglev system
NASA Astrophysics Data System (ADS)
Yildizer, Irfan; Cansiz, Ahmet; Ozturk, Kemal
2016-09-01
Optimization of the levitation for superconducting Maglev systems requires effective use of vertical and guidance forces during the operation. In this respect the levitation and guidance forces in terms of various permanent magnet array configurations are analyzed. The arrangements of permanent magnet arrays interacting with the superconductor are configured for the purpose of increasing the magnetic flux density. According to configurations, modeling the interaction forces between the permanent magnet and the superconductor are established in terms of the frozen image model. The model is complemented with the analytical calculations and provides a reasonable agreement with the experiments. The agreement of the analytical calculation associated with the frozen image model indicates a strong case to establish an optimization, in which provides preliminary analysis before constructing more complex Maglev system.
Coupled vibration analysis of Maglev vehicle-guideway while standing still or moving at low speeds
NASA Astrophysics Data System (ADS)
Kim, Ki-Jung; Han, Jong-Boo; Han, Hyung-Suk; Yang, Seok-Jo
2015-04-01
Dynamic instability, that is, resonance, may occur on an electromagnetic suspension-type Maglev that runs over the elevated guideway, particularly at very low speeds, due to the flexibility of the guideway. An analysis of the dynamic interaction between the vehicle and guideway is required at the design stage to investigate such instability, setting slender guideway in design direction for reducing construction costs. In addition, it is essential to design an effective control algorithm to solve the problem of instability. In this article, a more detailed model for the dynamic interaction of vehicle/guideway is proposed. The proposed model incorporates a 3D full vehicle model based on virtual prototyping, flexible guideway by a modal superposition method and levitation electromagnets including feedback controller into an integrated model. By applying the proposed model to an urban Maglev vehicle newly developed for commercial application, an analysis of the instability phenomenon and an investigation of air gap control performance are carried out through a simulation.
Backstepping fuzzy-neural-network control design for hybrid maglev transportation system.
Wai, Rong-Jong; Yao, Jing-Xiang; Lee, Jeng-Dao
2015-02-01
This paper focuses on the design of a backstepping fuzzy-neural-network control (BFNNC) for the online levitated balancing and propulsive positioning of a hybrid magnetic levitation (maglev) transportation system. The dynamic model of the hybrid maglev transportation system including levitated hybrid electromagnets to reduce the suspension power loss and the friction force during linear movement and a propulsive linear induction motor based on the concepts of mechanical geometry and motion dynamics is first constructed. The ultimate goal is to design an online fuzzy neural network (FNN) control methodology to cope with the problem of the complicated control transformation and the chattering control effort in backstepping control (BSC) design, and to directly ensure the stability of the controlled system without the requirement of strict constraints, detailed system information, and auxiliary compensated controllers despite the existence of uncertainties. In the proposed BFNNC scheme, an FNN control is utilized to be the major control role by imitating the BSC strategy, and adaptation laws for network parameters are derived in the sense of projection algorithm and Lyapunov stability theorem to ensure the network convergence as well as stable control performance. The effectiveness of the proposed control strategy for the hybrid maglev transportation system is verified by experimental results, and the superiority of the BFNNC scheme is indicated in comparison with the BSC strategy and the backstepping particle-swarm-optimization control system in previous research.
NASA Astrophysics Data System (ADS)
Ma, G. T.; Wang, J. S.; Lin, Q. X.; Liu, M. X.; Deng, Z. G.; Li, X. C.; Liu, H. F.; Zheng, J.; Wang, S. Y.
2009-11-01
The lateral restorable characteristics of a translational symmetry high- T c superconducting maglev system are investigated by measuring its resonant frequency ( fRF) after a lateral displacement. The difference between whether this lateral displacement is restorable, meaning elastic or inelastic, is determined by whether or not the maglev body returns to its original position after a lateral displacement. The maximum restorable lateral displacement ( δMRLD) is determined by the sudden change of the fRF vs. the maximum lateral displacement ( δMLD) curve. The fRF of the high- T c superconducting maglev system with different field-cooling height (FCH) and working height (WH) was obtained from the frequency domain vibration curve which was measured by a vibration measurement system. The results showed that, the δMRLD was reduced when the WH was decreased. The maximum restorable guidance force ( FMRGF) was found to not always increase with the lowering of the WH for the same FCH. The lateral restorable stiffness ( kLRS) was always enhanced with the decrease of the WH. The decrease of the δMRLD with the WH is interpreted by the fact that, the tangential field component (Δ H) across the surface of the high- T c superconductor (HTSC) is easier to exceed the J cλ value ( J c is the critical current density and λ is the London penetration depth) when the WH is lowered, and this makes the trapped flux lines become more susceptible in escaping its pinning sites.
Kinetic-energy-momentum tensor in electrodynamics
NASA Astrophysics Data System (ADS)
Sheppard, Cheyenne J.; Kemp, Brandon A.
2016-01-01
We show that the Einstein-Laub formulation of electrodynamics is invalid since it yields a stress-energy-momentum (SEM) tensor that is not frame invariant. Two leading hypotheses for the kinetic formulation of electrodynamics (Chu and Einstein-Laub) are studied by use of the relativistic principle of virtual power, mathematical modeling, Lagrangian methods, and SEM transformations. The relativistic principle of virtual power is used to demonstrate the field dynamics associated with energy relations within a relativistic framework. Lorentz transformations of the respective SEM tensors demonstrate the relativistic frameworks for each studied formulation. Mathematical modeling of stationary and moving media is used to illustrate the differences and discrepancies of specific proposed kinetic formulations, where energy relations and conservation theorems are employed. Lagrangian methods are utilized to derive the field kinetic Maxwell's equations, which are studied with respect to SEM tensor transforms. Within each analysis, the Einstein-Laub formulation violates special relativity, which invalidates the Einstein-Laub SEM tensor.
Continuum mechanics, stresses, currents and electrodynamics.
Segev, Reuven
2016-04-28
The Eulerian approach to continuum mechanics does not make use of a body manifold. Rather, all fields considered are defined on the space, or the space-time, manifolds. Sections of some vector bundle represent generalized velocities which need not be associated with the motion of material points. Using the theories of de Rham currents and generalized sections of vector bundles, we formulate a weak theory of forces and stresses represented by vector-valued currents. Considering generalized velocities represented by differential forms and interpreting such a form as a generalized potential field, we present a weak formulation of pre-metric, p-form electrodynamics as a natural example of the foregoing theory. Finally, it is shown that the assumptions leading to p-form electrodynamics may be replaced by the condition that the force functional is continuous with respect to the flat topology of forms.
Magnetic Levitation Experiments with the Electrodynamic Wheel
NASA Astrophysics Data System (ADS)
Cordrey, Vincent; Gutarra-Leon, Angel; Gaul, Nathan; Majewski, Walerian
Our experiments explored inductive magnetic levitation using circular Halbach arrays with the strong variable magnetic field on the outer rim of the ring. Such a system is usually called an Electrodynamic Wheel (EDW). Rotating this wheel around a horizontal axis above a flat conducting surface should induce eddy currents in said surface through the variable magnetic flux. The eddy currents produce, in turn, their own magnetic fields which interact with the magnets of the EDW. We constructed two Electrodynamic Wheels with different diameters and demonstrated that the magnetic interactions produce both lift and drag forces on the EDW which can be used for levitation and propulsion of the EDW. The focus of our experiments is the direct measurement of lift and drag forces to compare with theoretical models using wheels of two different radii. Supported by Grants from the Virginia Academy of Science, Society of Physics Students, Virginia Community College System, and the NVCC Educational Foundation.
Electrodynamic tether system study: Extended study
NASA Technical Reports Server (NTRS)
1988-01-01
This document is the final report of a study performed by Ball Space Systems Division (BSSD) for the NASA Johnson Space Center under an extension to contract NAS9-17666. The tasks for the extended study were as follows: (1) Define an interface between the Electrodynamic Tether System (ETS) and the Space Station (SS); (2) Identify growth paths for the 100 kW ETS defined in the original study to a 200 kW level of performance; (3) Quantify orbit perturbations caused by cyclic day/night operations of a Plasma Motor/Generator (PMG) on the SS and explore methods of minimizing these effects; (4) Define the analyses, precursor technology, ground tests, and precursor demonstrations leading up to a demonstration mission for an electrodynamic tether system that would be capable of producing maneuvering thrust levels of 25 newtons; and (5) Propose a development schedule for the demonstration mission and preliminary cost estimates.
Students' difficulties with vector calculus in electrodynamics
NASA Astrophysics Data System (ADS)
Bollen, Laurens; van Kampen, Paul; De Cock, Mieke
2015-12-01
Understanding Maxwell's equations in differential form is of great importance when studying the electrodynamic phenomena discussed in advanced electromagnetism courses. It is therefore necessary that students master the use of vector calculus in physical situations. In this light we investigated the difficulties second year students at KU Leuven encounter with the divergence and curl of a vector field in mathematical and physical contexts. We have found that they are quite skilled at doing calculations, but struggle with interpreting graphical representations of vector fields and applying vector calculus to physical situations. We have found strong indications that traditional instruction is not sufficient for our students to fully understand the meaning and power of Maxwell's equations in electrodynamics.
Electrodynamics of planar Archimedean spiral resonator
NASA Astrophysics Data System (ADS)
Maleeva, N.; Averkin, A.; Abramov, N. N.; Fistul, M. V.; Karpov, A.; Zhuravel, A. P.; Ustinov, A. V.
2015-07-01
We present a theoretical and experimental study of electrodynamics of a planar spiral superconducting resonator of a finite length. The resonator is made in the form of a monofilar Archimedean spiral. By making use of a general model of inhomogeneous alternating current flowing along the resonator and specific boundary conditions on the surface of the strip, we obtain analytically the frequencies fn of resonances which can be excited in such system. We also calculate corresponding inhomogeneous RF current distributions ψ n ( r ) , where r is the coordinate across a spiral. We show that the resonant frequencies and current distributions are well described by simple relationships f n = f 1 n and ψ n ( r ) ≃ sin [ π n ( r / R e ) 2 ] , where n = 1 , 2... and Re is the external radius of the spiral. Our analysis of electrodynamic properties of spiral resonators' is in good agreement with direct numerical simulations and measurements made using specifically designed magnetic probe and laser scanning microscope.
Quantum electrodynamics near a photonic bandgap
NASA Astrophysics Data System (ADS)
Liu, Yanbing; Houck, Andrew A.
2017-01-01
Photonic crystals are a powerful tool for the manipulation of optical dispersion and density of states, and have thus been used in applications from photon generation to quantum sensing with nitrogen vacancy centres and atoms. The unique control provided by these media makes them a beautiful, if unexplored, playground for strong-coupling quantum electrodynamics, where a single, highly nonlinear emitter hybridizes with the band structure of the crystal. Here we demonstrate that such a hybridization can create localized cavity modes that live within the photonic bandgap, whose localization and spectral properties we explore in detail. We then demonstrate that the coloured vacuum of the photonic crystal can be employed for efficient dissipative state preparation. This work opens exciting prospects for engineering long-range spin models in the circuit quantum electrodynamics architecture, as well as new opportunities for dissipative quantum state engineering.
Alternative formulations of magnetospheric plasma electrodynamics
NASA Technical Reports Server (NTRS)
Cragin, B. L.; Heikkila, W. J.
1981-01-01
The fundamental equations of magnetospheric plasma electrodynamics are considered from a theoretical standpoint that stresses the basic equivalence of various seemingly different formal representations. The mathematical properties of vector fields are reviewed, and their implications in electrodynamics are studied. The irrotational and solenoidal parts of the electric field are associated with two physically distinct types of sources. Relativistic covariance and gauge invariance in electromagnetic theory are reviewed and discussed in the context of an approach in which the mathematical properties of vector fields are taken as primary concepts. Special attention is given to the use and interpretation of the Coulomb gauge potential functions. This choice of gauge is sometimes regarded with undue suspicion, possibly because of a certain paradox concerning causality. The paradox is discussed and resolved. Useful properties of the Coulomb gauge are identified. These need not be limited to the case of slow time variations and can extend beyond the limits of validity of ideal MHD theory.
Middle Atmosphere Electrodynamics During a Thunderstorm
NASA Technical Reports Server (NTRS)
Croskey, Charles L.
1996-01-01
Rocket-based instrumentation investigations of middle atmospheric electrodynamics during thunderstorms were conducted in coordination with balloon-measurements at Wallops Island, Virginia. Middle atmosphere electrodynamics and energy coupling are of particular importance to associated electrical processes at lower and higher altitudes. Objectives of this research effort included: (1) investigation of thunderstorm effects on middle atmosphere electrical structure, including spatial and temporal dependence; (2) characterization of electric field transients and the associated energy deposited at various altitudes; (3) evaluation of the vertical Maxwell current density over a thunderstorm to study the coupling of energy to higher altitudes; and (4) investigation of the coupling of energy to the ionosphere and the current supplied to the 'global circuit.'
EMC Test Report Electrodynamic Dust Shield
NASA Technical Reports Server (NTRS)
Carmody, Lynne M.; Boyette, Carl B.
2014-01-01
This report documents the Electromagnetic Interference E M I evaluation performed on the Electrodynamic Dust Shield (EDS) which is part of the MISSE-X System under the Electrostatics and Surface Physics Laboratory at Kennedy Space Center. Measurements are performed to document the emissions environment associated with the EDS units. The purpose of this report is to collect all information needed to reproduce the testing performed on the Electrodynamic Dust Shield units, document data gathered during testing, and present the results. This document presents information unique to the measurements performed on the Bioculture Express Rack payload; using test methods prepared to meet SSP 30238 requirements. It includes the information necessary to satisfy the needs of the customer per work order number 1037104. The information presented herein should only be used to meet the requirements for which it was prepared.
Time-symmetric electrodynamics and quantum measurement
NASA Astrophysics Data System (ADS)
Pegg, D. T.
The application of the Wheeler-Feynman theory of time-symmetric electrodynamics to obtain definite answers to questions concerning the objective existence of quantum states in an optical EPR type of experiment is discussed. This theory allows the influence of the detector on the system being studied to be taken into account. The result is an entirely fresh understanding of experiments of the Kocher-Commins type.
Middle atmospheric electrodynamics - Status and future
NASA Technical Reports Server (NTRS)
Goldberg, R. A.
1984-01-01
Recent theoretical and observational studies of middle atmosphere electrodynamics are reviewed. Attention is given to observations of large electric fields in the mesosphere and stratosphere which suggest magnitudes of about one volt per sq m. Recommendations are offered with respect to areas of future study, with emphasis on studies of the morphology of large electric fields, and their relationship with external influences such as magnetospheric electric fields and tropospheric thunderstorms.
The Foundations of Linear Stochastic Electrodynamics
NASA Astrophysics Data System (ADS)
Peña, L. De La; Cetto, A. M.
2006-03-01
An analysis is briefly presented of the possible causes of the failure of stochastic electrodynamics (SED) when applied to systems with nonlinear forces, on the basis that the main principles of the theory are correct. In light of this analysis, an alternative approach to the theory is discussed, whose postulates allow to establish contact with quantum mechanics in a natural way. The ensuing theory, linear SED, confirms the essential role of the vacuum particle interaction as the source of quantum phenomena.
Quantum Electrodynamics of Heavy Ions and Atoms
Shabaev, V. M.; Artemyev, A. N.; Glazov, D. A.; Tupitsyn, I. I.; Volotka, A. V.; Yerokhin, V. A.
2006-11-07
The present status of quantum electrodynamics (QED) theory of heavy few-electrons is reviewed. The theoretical results are compared with available experimental data. A special attention is focused on tests of QED at strong fields and on determination of the fundamental constants. A recent progress on calculations of the QED corrections to the parity nonconserving 6s-7s transition amplitude in neutral Cs is also discussed.
Holographic paramagnetism-ferromagnetism phase transition with the nonlinear electrodynamics
NASA Astrophysics Data System (ADS)
Zhang, Cheng-Yuan; Wu, Ya-Bo; Zhang, Ya-Nan; Wang, Huan-Yu; Wu, Meng-Meng
2017-01-01
In the probe limit, we investigate the nonlinear electrodynamical effects of the both exponential form and the logarithmic form on the holographic paramagnetism-ferromagnetism phase transition in the background of a Schwarzschild-AdS black hole spacetime. Moreover, by comparing the exponential form of nonlinear electrodynamics with the logarithmic form of nonlinear electrodynamics and the Born-Infeld nonlinear electrodynamics which has been presented in Ref. [55], we find that the higher nonlinear electrodynamics correction makes the critical temperature smaller and the magnetic moment harder form in the case without external field. Furthermore, the increase of nonlinear parameter b will result in extending the period of the external magnetic field. Especially, the effect of the exponential form of nonlinear electrodynamics on the periodicity of hysteresis loop is more noticeable.
Modelling of auroral electrodynamical processes: Magnetosphere to mesosphere. Final Report
Chiu, Y.T.; Gorney, D.J.
1982-01-01
Research conducted on auroral electrodynamic coupling between the magnetosphere and ionosphere-atmosphere in support of the development of a global scale kinetic plasma theory is reviewed. Topics covered include electric potential structure in the evening sector, morning and dayside auroras, auroral plasma formation, electrodynamic coupling with the thermosphere, and auroral electron interaction with the atmosphere.
Maglev demonstration, design and develoment plan. Final report, February 1990-August 1994
Yarwood, G.; Gray, H.A.; Ligocki, M.P.; Whitten, G.Z.
1994-08-01
This study examines the feasibility of a regional high speed magnetic levitation (MAGLEV) system connecting the Greater Pittsburgh airport with strategic stops between the Midwest and the East Coast. A suburban commuter system, which operates on the same lines as the regional system, is also investigated. The first link of the regional and suburban MAGLEV system consists of a demonstration line connecting the Greater Pittsburgh International Airport with downtown Pittsburgh. This study considers the economic value of such a system from the aspects of transportation, manufacturing and economic development. The study concludes that an investment of $41 billion over the next 30 years would be required to build a regional MAGLEV system, cover its operating cost and produce enough additional transportation revenue to pay back part of this investment in the private sector financial markets. A substantial portion of this investment must come from the public sector. The additional economic activity generated by this investment would be over $78 billion. Over 675,000 person-years of work would be created by such a venture.The current regulatory approach to achieving ozone and related air quality standards is based on emissions estimation and modeling. In recent years, several studies have attempted to evaluate the emissions estimates and methods against ambient measurements by comparing non-methane organic compound (NMOC) species profiles, NMOC:NOx ratios, CO:NOx ratios, and using receptor modeling of NMOCs. Areas of interest have included the relative contributions of mobile, stationary, and biogenic sources, and evidence for underestimation of sources and/or missing sources. However, over the same time period the emission estimates have also been revised to reflect the latest information.
Design and validation of a slender guideway for Maglev vehicle by simulation and experiment
NASA Astrophysics Data System (ADS)
Han, Jong-Boo; Han, Hyung-Suk; Kim, Sung-Soo; Yang, Seok-Jo; Kim, Ki-Jung
2016-03-01
Normally, Maglev (magnetic levitation) vehicles run on elevated guideways. The elevated guideway must satisfy various load conditions of the vehicle, and has to be designed to ensure ride quality, while ensuring that the levitation stability of the vehicle is not affected by the deflection of the guideway. However, because the elevated guideways of Maglev vehicles in South Korea and other countries fabricated so far have been based on over-conservative design criteria, the size of the structures has increased. Further, from the cost perspective, they are unfavourable when compared with other light rail transits such as monorail, rubber wheel, and steel wheel automatic guided transit. Therefore, a slender guideway that does have an adverse effect on the levitation stability of the vehicle is required through optimisation of design criteria. In this study, to predict the effect of various design parameters of the guideway on the dynamic behaviour of the vehicle, simulations were carried out using a dynamics model similar to the actual vehicle and guideway, and a limiting value of deflection ratio of the slender guideway to ensure levitation control is proposed. A guideway that meets the requirement as per the proposed limit for deflection ratio was designed and fabricated, and through a driving test of the vehicle, the validity of the slender guideway was verified. From the results, it was confirmed that although some increase in airgap and cabin acceleration was observed with the proposed slender guideway when compared with the conventional guideway, there was no notable adverse effect on the levitation stability and ride quality of the vehicle. Therefore, it can be inferred that the results of this study will become the basis for establishing design criteria for slender guideways of Maglev vehicles in future.
Subclassical fields and polarization in electrodynamics
Planat, Mathieu; Polonyi, Janos
2010-08-15
Expectation values of the electromagnetic field and the electric current are introduced at space-time resolution which belongs to the quantum domain. These allow us to approach some key features of classical electrodynamics from the underlying QED. One is the emergence of the radiation field in the retarded solution of the Maxwell equation, derived from an action principle. Another question discussed is the systematic derivation of the polarizability of a charge system. Furthermore, the decoherence and the consistency of the photon field are established by a perturbative calculation of the reduced density matrix for the electromagnetic field within the closed time path formalism.
Cavity quantum electrodynamics: coherence in context.
Mabuchi, H; Doherty, A C
2002-11-15
Modern cavity quantum electrodynamics (cavity QED) illuminates the most fundamental aspects of coherence and decoherence in quantum mechanics. Experiments on atoms in cavities can be described by elementary models but reveal intriguing subtleties of the interplay of coherent dynamics with external couplings. Recent activity in this area has pioneered powerful new approaches to the study of quantum coherence and has fueled the growth of quantum information science. In years to come, the purview of cavity QED will continue to grow as researchers build on a rich infrastructure to attack some of the most pressing open questions in micro- and mesoscopic physics.
International Space Station Electrodynamic Tether Reboost Study
NASA Technical Reports Server (NTRS)
Johnson, L.; Herrmann, M.
1998-01-01
The International Space Station (ISS) will require periodic reboost due to atmospheric aerodynamic drag. This is nominally achieved through the use of thruster firings by the attached Progress M spacecraft. Many Progress flights to the ISS are required annually. Electrodynamic tethers provide an attractive alternative in that they can provide periodic reboost or continuous drag cancellation using no consumables, propellant, nor conventional propulsion elements. The system could also serve as an emergency backup reboost system used only in the event resupply and reboost are delayed for some reason.
Equations of motion for variational electrodynamics
NASA Astrophysics Data System (ADS)
De Luca, Jayme
2016-04-01
We extend the variational problem of Wheeler-Feynman electrodynamics by generalizing the electromagnetic functional to a local space of absolutely continuous trajectories possessing a derivative (velocities) of bounded variation. We show here that the Gateaux derivative of the generalized functional defines two partial Lagrangians for variations in our generalized local space, one for each particle. We prove that the critical-point conditions of the generalized variational problem are: (i) the Euler-Lagrange equations must hold Lebesgue-almost-everywhere and (ii) the momentum of each partial Lagrangian and the Legendre transform of each partial Lagrangian must be absolutely continuous functions, generalizing the Weierstrass-Erdmann conditions.
Soliton configurations in generalized Mie electrodynamics
Rybakov, Yu. P.
2011-07-15
The generalization of the Mie electrodynamics within the scope of the effective 8-spinor field model is suggested, with the Lagrangian including Higgs-like potential and higher degrees of the invariant A{sub Micro-Sign }A{sup Micro-Sign }. Using special Brioschi 8-spinor identity, we show that the model includes the Skyrme and the Faddeev models as particular cases. We investigate the large-distance asymptotic of static solutions and estimate the electromagnetic contribution to the energy of the localized charged configuration.
Path integral quantization of generalized quantum electrodynamics
Bufalo, R.; Pimentel, B. M.; Zambrano, G. E. R.
2011-02-15
In this paper, a complete covariant quantization of generalized electrodynamics is shown through the path integral approach. To this goal, we first studied the Hamiltonian structure of the system following Dirac's methodology and, then, we followed the Faddeev-Senjanovic procedure to obtain the transition amplitude. The complete propagators (Schwinger-Dyson-Fradkin equations) of the correct gauge fixation and the generalized Ward-Fradkin-Takahashi identities are also obtained. Afterwards, an explicit calculation of one-loop approximations of all Green's functions and a discussion about the obtained results are presented.
Testing nonlinear vacuum electrodynamics with Michelson interferometry
NASA Astrophysics Data System (ADS)
Schellstede, Gerold O.; Perlick, Volker; Lämmerzahl, Claus
2015-07-01
We discuss the theoretical foundations for testing nonlinear vacuum electrodynamics with Michelson interferometry. Apart from some nondegeneracy conditions to be imposed, our discussion applies to all nonlinear electrodynamical theories of the Plebański class, i.e., to all Lagrangians that depend only on the two Lorentz-invariant scalars quadratic in the field strength. The main idea of the experiment proposed here is to use the fact that, according to nonlinear electrodynamics, the phase velocity of light should depend on the strength and on the direction of an electromagnetic background field. There are two possible experimental setups for testing this prediction with Michelson interferometry. The first possibility is to apply a strong electromagnetic field to the beam in one arm of the interferometer and to compare the situation where the field is switched on with the situation where it is switched off. The second possibility is to place the whole interferometer in a strong electromagnetic field and to rotate it. If an electromagnetic field is placed in one arm, the interferometer could have the size of a gravitational wave detector, i.e., an arm length of several hundred meters. If the whole interferometer is placed in an electromagnetic field, one would have to do the experiment with a tabletop interferometer. As an alternative to a traditional Michelson interferometer, one could use a pair of optical resonators that are not bigger than a few centimeters. Then the whole apparatus would be placed in the background field and one would either compare the situation where the field is switched on with the situation where it is switched off or one would rotate the apparatus with the field kept switched on. We derive the theoretical foundations for these types of experiments, in the context of an unspecified nonlinear electrodynamics of the Plebański class, and we discuss their feasibility. A null result of the experiment would place bounds on the parameters of the
Electrodynamics of the high latitude middle atmosphere
NASA Technical Reports Server (NTRS)
Goldberg, R. A.
1987-01-01
Atmospheric electrodynamics is reviewed. The discovery of apparent large (V/m) electric fields within the mesosphere invites the possibility for this region to be electrically active. Observations of the V/m field were made at high latitudes even under active conditions, but always below heights where significant enhancements in electrical conductivity are found to occur. Two measurements at Andoya (Norway) show anticorrelation of horizontal field directions with wind directions, suggesting a mechanism which involves mechanical separation of charged aerosols. Reported evidence for such aerosols makes this concept more viable. Noctilucent clouds and mesospheric turbulence, and their influence on the local electrical environment are mentioned.
Electrodynamics and plasma processes in the ionosphere
NASA Technical Reports Server (NTRS)
Heelis, R. A.
1987-01-01
The paper examines the advances achieved between 1983 and 1986 on understanding ionospheric electrodynamics and associated plasma processes, including an assessment of the roles of the E- and F-region neutral winds in providing the large-scale electric field in the ionosphere, as well as of the influence of electric fields of magnetospheric origin on the motion and distribution of plasma. Studies of the factors affecting the creation and evolution of plasma structure with many different scale sizes are discussed. Consideration is also given to the ground-based and in situ techniques used in these studies.
Quantum Electrodynamical Shifts in Multivalent Heavy Ions
NASA Astrophysics Data System (ADS)
Tupitsyn, I. I.; Kozlov, M. G.; Safronova, M. S.; Shabaev, V. M.; Dzuba, V. A.
2016-12-01
The quantum electrodynamics (QED) corrections are directly incorporated into the most accurate treatment of the correlation corrections for ions with complex electronic structure of interest to metrology and tests of fundamental physics. We compared the performance of four different QED potentials for various systems to access the accuracy of QED calculations and to make a prediction of highly charged ion properties urgently needed for planning future experiments. We find that all four potentials give consistent and reliable results for ions of interest. For the strongly bound electrons, the nonlocal potentials are more accurate than the local potential.
Quantum Electrodynamical Shifts in Multivalent Heavy Ions.
Tupitsyn, I I; Kozlov, M G; Safronova, M S; Shabaev, V M; Dzuba, V A
2016-12-16
The quantum electrodynamics (QED) corrections are directly incorporated into the most accurate treatment of the correlation corrections for ions with complex electronic structure of interest to metrology and tests of fundamental physics. We compared the performance of four different QED potentials for various systems to access the accuracy of QED calculations and to make a prediction of highly charged ion properties urgently needed for planning future experiments. We find that all four potentials give consistent and reliable results for ions of interest. For the strongly bound electrons, the nonlocal potentials are more accurate than the local potential.
Status of The General Atomics Low Speed Urban Maglev Technology Development Program
Gurol, S; Baldi, R; Bever, D; Post, R
2004-06-16
This paper presents the status of General Atomics Urban Maglev Program. The development provides an innovative approach for low speed transportation suitable for very challenging urban environments. Permanent magnets arranged in a 'Halbach' array configuration produce a relatively stiff magnetic suspension operating with an air gap of 25 mm. The project has progressed from design and prototype hardware testing, to the construction of a 120-meter full-scale test track, located in San Diego, California. Dynamic testing of the levitation, propulsion and guidance systems is being performed.
Static and dynamic stability of the guidance force in a side-suspended HTS maglev system
NASA Astrophysics Data System (ADS)
Zhou, Dajin; Cui, Chenyu; Zhao, Lifeng; Zhang, Yong; Wang, Xiqing; Zhao, Yong
2017-02-01
The static and dynamic stability of the guidance force in a side-suspended HTS-PMG (permanent magnetic guideway) system were studied theoretically and experimentally. It is found that there are two types of guidance force that exist in the HTS-PMG system, which are sensitive to the levitation gap and the arrangement of YBCO bulks around the central axis of the PMG. An optimized YBCO array was used to stabilize the system, which enabled a side-suspended HTS-PMG maglev vehicle to run stably at 102 km h-1 on a circular test track with 6.5 m in diameter.
New levitation scheme with AC superconducting magnet for EDS MAGLEV system
Kim, D.H.; Lee, J.K.; Hahn, S.Y.; Cha, G.
1996-09-01
This paper proposes a new magnetic levitation scheme which is able to generate levitation force for all speeds including a standstill. Auxiliary wheels which are needed in EDS MAGLEV vehicle can be eliminated. This scheme uses AC superconducting magnets to generate levitation force. In this paper, magnetic fields, forces and power dissipations generated by AC magnets moving above a conducting slab are calculated analytically. Results of calculation show characteristics of EDS system with AC magnet, such as levitation force and loss, are superior to those of EDS system with DC magnets for all speeds.
Fujie, Junji
1999-09-01
The PLG (combined Propulsion, Levitation and Guidance) method was proposed for a more favorable Maglev ground coil system, combining the functions of propulsion, levitation, and guidance of the vehicle into one coil. Research and development is currently being conducted on this method. In this paper, the characteristics of a newly-structured system for the PLG method is examined. The discussed characteristics include propulsion, levitation-guidance, vehicle dynamics in the cases of problems with the superconducting magnets, and the magnetic field on board the vehicle.
Study on Fuzzy Adaptive Fractional Order PIλDμ Control for Maglev Guiding System
NASA Astrophysics Data System (ADS)
Hu, Qing; Hu, Yuwei
The mathematical model of the linear elevator maglev guiding system is analyzed in this paper. For the linear elevator needs strong stability and robustness to run, the integer order PID was expanded to the fractional order, in order to improve the steady state precision, rapidity and robustness of the system, enhance the accuracy of the parameter in fractional order PIλDμ controller, the fuzzy control is combined with the fractional order PIλDμ control, using the fuzzy logic achieves the parameters online adjustment. The simulations reveal that the system has faster response speed, higher tracking precision, and has stronger robustness to the disturbance.
49 CFR 268.7 - Federal/State share and restrictions on the uses of Federal Maglev Funds.
Code of Federal Regulations, 2013 CFR
2013-10-01
... 49 Transportation 4 2013-10-01 2013-10-01 false Federal/State share and restrictions on the uses of Federal Maglev Funds. 268.7 Section 268.7 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION MAGNETIC...
49 CFR 268.7 - Federal/State share and restrictions on the uses of Federal Maglev Funds.
Code of Federal Regulations, 2012 CFR
2012-10-01
... 49 Transportation 4 2012-10-01 2012-10-01 false Federal/State share and restrictions on the uses of Federal Maglev Funds. 268.7 Section 268.7 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION MAGNETIC...
49 CFR 268.7 - Federal/State share and restrictions on the uses of Federal Maglev Funds.
Code of Federal Regulations, 2014 CFR
2014-10-01
... 49 Transportation 4 2014-10-01 2014-10-01 false Federal/State share and restrictions on the uses of Federal Maglev Funds. 268.7 Section 268.7 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION MAGNETIC...
49 CFR 268.7 - Federal/State share and restrictions on the uses of Federal Maglev Funds.
Code of Federal Regulations, 2010 CFR
2010-10-01
... 49 Transportation 4 2010-10-01 2010-10-01 false Federal/State share and restrictions on the uses of Federal Maglev Funds. 268.7 Section 268.7 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION MAGNETIC...
49 CFR 268.7 - Federal/State share and restrictions on the uses of Federal Maglev Funds.
Code of Federal Regulations, 2011 CFR
2011-10-01
... 49 Transportation 4 2011-10-01 2011-10-01 false Federal/State share and restrictions on the uses of Federal Maglev Funds. 268.7 Section 268.7 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION MAGNETIC...
Solar Flare Impacts on Ionospheric Electrodynamics
NASA Technical Reports Server (NTRS)
Qian, Liying; Burns, Alan G.; Solomon, Stanley C.; Chamberlin, Phillip C.
2012-01-01
The sudden increase of X-ray and extreme ultra-violet irradiance during flares increases the density of the ionosphere through enhanced photoionization. In this paper, we use model simulations to investigate possible additional contributions from electrodynamics, finding that the vertical E X B drift in the magnetic equatorial region plays a significant role in the ionosphere response to solar flares. During the initial stage of flares, upward E X B drifts weaken in the magnetic equatorial region, causing a weakened equatorial fountain effect, which in turn causes lowering of the peak height of the F2 region and depletion of the peak electron density of the F2 region. In this initial stage, total electron content (TEC) enhancement is predominantly determined by solar zenith angle control of photoionization. As flares decay, upward E X B drifts are enhanced in the magnetic equatorial region, causing increases of the peak height and density of the F2 region. This process lasts for several hours, causing a prolonged F2-region disturbance and TEC enhancement in the magnetic equator region in the aftermath of flares. During this stage, the global morphology of the TEC enhancement becomes predominantly determined by these perturbations to the electrodynamics of the ionosphere.
Space Station Reboost with Electrodynamic Tethers
NASA Technical Reports Server (NTRS)
Vas, Irwin E.; Kelly, Thomas J.; Scarl, Ethan A.
1999-01-01
This paper presents the results of a study of an electrodynamic tether system to reboost the International Space Station (ISS). One recommendation is to use a partially bare tether for electron collection. Locations are suggested as to where the tether system is to be attached at the space station. The effects of the tether system on the microgravity environment may actually be beneficial, because the system can neutralize aerodrag during quiescent periods and, if deployed from a movable boom, can permit optimization of laboratory positioning with respect to acceleration contours. Alternative approaches to tether deployment and retrieval are discussed. It is shown that a relatively short tether system, 7 km long, operating at a power level of 5 kW could provide cumulative savings or over a billion dollars during a 10-year period ending in 2012. This savings is the direct result of a reduction in the number or nights that would otherwise be required to deliver propellant for reboost, with larger cost savings for higher tether usage. In addition to economic considerations, an electrodynamic tether promises a practical backup system that could ensure ISS survival in the event of an (otherwise) catastrophic delay in propellant delivery.
Electrodynamics with a Future Conformal Horizon
NASA Astrophysics Data System (ADS)
Ibison, Michael
2010-12-01
We investigate the impact of singularities occurring at future times in the Friedmann equations expressed in conformal coordinates to determine the consequences of extending the time coordinate through the singularity for the physics of matter and radiation occupying just one side. Mostly this involves investigation of the relationship between the metric with line element ds2 = a2(t)(dt2-dx2) and time reversal symmetry within electrodynamics. It turns out compatibility between these two is possible only if there is a singular physical event at the time of the singularity or if the topology is not trivial. In both cases the singularity takes on the appearance of a time-like mirror. We are able to demonstrate a relationship between the broken time symmetry in electrodynamics characterized by retarded radiation and radiation reaction and the absolute conformal time relative to the time of the singularity, i.e. between the Electromagnetic and Cosmological arrows of time. It is determined that the Wheeler-Feynman reasoning but with the future absorber replaced by the Cosmological mirror leads to a conflict with observation unless matter is strongly bound electromagnetically to the environment.
Electrodynamics with a Future Conformal Horizon
Ibison, Michael
2010-12-22
We investigate the impact of singularities occurring at future times in the Friedmann equations expressed in conformal coordinates to determine the consequences of extending the time coordinate through the singularity for the physics of matter and radiation occupying just one side. Mostly this involves investigation of the relationship between the metric with line element ds{sup 2} a{sup 2}(t)(dt{sup 2}-dx{sup 2}) and time reversal symmetry within electrodynamics. It turns out compatibility between these two is possible only if there is a singular physical event at the time of the singularity or if the topology is not trivial. In both cases the singularity takes on the appearance of a time-like mirror. We are able to demonstrate a relationship between the broken time symmetry in electrodynamics characterized by retarded radiation and radiation reaction and the absolute conformal time relative to the time of the singularity, i.e. between the Electromagnetic and Cosmological arrows of time. It is determined that the Wheeler-Feynman reasoning but with the future absorber replaced by the Cosmological mirror leads to a conflict with observation unless matter is strongly bound electromagnetically to the environment.
Spacecraft Solar Sails Containing Electrodynamic Tethers
NASA Technical Reports Server (NTRS)
Johnson, Les; Matloff, Greg
2005-01-01
A report discusses a proposal to use large, lightweight solar sails embedded with electrodynamic tethers (essentially, networks of wires) to (1) propel robotic spacecraft to distant planets, then (2) exploit the planetary magnetic fields to capture the spacecraft into orbits around the planets. The purpose of the proposal is, of course, to make it possible to undertake long interplanetary missions without incurring the large cost and weight penalties of conventional rocket-type propulsion systems. Through transfer of momentum from reflected solar photons, a sail would generate thrust outward from the Sun. Upon arrival in the vicinity of a planet, the electrodynamic tethers would be put to use: Motion of the spacecraft across the planetary magnetic field would induce electric currents in the tether wires, giving rise to an electromagnetic drag force that would be exploited to brake the spacecraft for capture into orbit. The sail with embedded tethers would be made to spin to provide stability during capture. Depending upon the requirements of a particular application, it could be necessary to extend the tether to a diameter greater than that of the sail.
Recent Developments in Linear Stochastic Electrodynamics
NASA Astrophysics Data System (ADS)
de la Peña, L.; Cetto, A. M.
2006-01-01
A detailed analysis of stochastic electrodynamics (SED) as a foundation for quantum mechanics has shown that the reasons for its failure in the case of nonlinear forces are not to be ascribed to the founding principles of the theory but to the approximation methods introduced, particularly the use of the Fokker-Planck approximation and perturbation theory. To recover the intrinsic possibilities of SED a new, non perturbative approach has been developed, namely linear stochastic electrodynamics (LSED). We here present the basic principles on which LSED is constructed. The demand that the solutions of the SED problem comply with as few as three principles, each one of which is shown to have a clear physical meaning, leads in a natural way to the quantum mechanical description in its Heisenberg form. We briefly re-examine some of the most often discussed conceptual problems of quantum mechanics from the point of view offered by the new theory and show that it offers well defined and clear physical anwers to them, within a realist and causal perspective. To conclude we add brief comments on a couple of predictions of the theory, the test of which could eventually lead to its validation or refutation.
Quantum-classical crossover in electrodynamics
Polonyi, Janos
2006-09-15
A classical field theory is proposed for the electric current and the electromagnetic field interpolating between microscopic and macroscopic domains. It represents a generalization of the density functional for the dynamics of the current and the electromagnetic field in the quantum side of the crossover and reproduces standard classical electrodynamics on the other side. The effective action derived in the closed time path formalism and the equations of motion follow from the variational principle. The polarization of the Dirac-sea can be taken into account in the quadratic approximation of the action by the introduction of the deplacement field strengths as in conventional classical electrodynamics. Decoherence appears naturally as a simple one-loop effect in this formalism. It is argued that the radiation time arrow is generated from the quantum boundary conditions in time by decoherence at the quantum-classical crossover and the Abraham-Lorentz force arises from the accelerating charge or from other charges in the macroscopic or the microscopic side, respectively. The functional form of the quantum renormalization group, the generalization of the renormalization group method for the density matrix, is proposed to follow the scale dependence through the quantum-classical crossover in a systematical manner.
Analysis and design of a speed and position system for maglev vehicles.
Dai, Chunhui; Dou, Fengshan; Song, Xianglei; Long, Zhiqiang
2012-01-01
This paper mainly researches one method of speed and location detection for maglev vehicles. As the maglev train doesn't have any physical contact with the rails, it has to use non-contact measuring methods. The technology based on the inductive loop-cable could fulfill the requirement by using an on-board antenna which could detect the alternating magnetic field produced by the loop-cable on rails. This paper introduces the structure of a speed and position system, and analyses the electromagnetic field produced by the loop-cable. The equivalent model of the loop-cable is given and the most suitable component of the magnetic flux density is selected. Then the paper also compares the alternating current (AC) resistance and the quality factor between two kinds of coils which the antenna is composed of. The effect of the rails to the signal receiving is also researched and then the structure of the coils is improved. Finally, considering the common-mode interference, 8-word coils are designed and analyzed.
Bing, A.J.; Parker, J.D.; Pristach, G.S.; Behara, C.; Gabriel, D.
1993-09-01
The use of magnetically levitated (maglev) vehicles for high-speed guided ground transportation has been proposed for passenger operations in the United States. As a result, a need exists for the assessment for the safety implications of this new form of technology to ensure passenger safety. This report contains the results of a detailed review of safety requirements to evaluate their suitability to maglev operations in the U.S. environment.
Combination Solar Sail and Electrodynamic Tether Propulsion System
NASA Technical Reports Server (NTRS)
Johnson, Charles L. (Inventor); Matloff, Gregory L. (Inventor)
2003-01-01
A propulsion system for a spacecraft includes a solar sail system and an electrodynamic tether system is presented. The solar sail system is used to generate propulsion to propel the spacecraft through space using solar photons and the electrodynamic tether system is used to generate propulsion to steer the spacecraft into orbit and to perform orbital maneuvers around a planet using the planet's magnetic field. The electrodynamic tether system can also be used to generate power for the spacecraft using the planet's magnetic field.
Implementation Options for the PROPEL Electrodynamic Tether Demonstration Mission
NASA Technical Reports Server (NTRS)
Bilen, Sven G.; Johnson, Les; Gilchrist, Brian E.; Hoyt, Robert P.; Elder, Craig H.; Fuhrhop, Keith P.; Scadera, Michael P.; Stone, Nobie H.
2014-01-01
The PROPEL flight mission concept will demonstrate the safe use of an electrodynamic tether for generating thrust. PROPEL is being designed to be a versatile electrodynamic-tether system for multiple end users and to be flexible with respect to platform. As such, several implementation options are being explored, including a comprehensive mission design for PROPEL with a mission duration of six months; a space demonstration mission concept design with configuration of a pair of tethered satellites, one of which is the Japanese H-II Transfer Vehicle; and an ESPA-based system. We report here on these possible implementation options for PROPEL. electrodynamic tether; PROPEL demonstration mission; propellantless propulsion
Unified theory of nonlinear electrodynamics and gravity
Torres-Gomez, Alexander; Krasnov, Kirill; Scarinci, Carlos
2011-01-15
We describe a class of unified theories of electromagnetism and gravity. The Lagrangian is of the BF type, with a potential for the B field, the gauge group is U(2) (complexified). Given a choice of the potential function the theory is a deformation of (complex) general relativity and electromagnetism, and describes just two propagating polarizations of the graviton and two of the photon. When gravity is switched off the theory becomes the usual nonlinear electrodynamics with a general structure function. The Einstein-Maxwell theory can be recovered by sending some of the parameters of the defining potential to zero, but for any generic choice of the potential the theory is indistinguishable from Einstein-Maxwell at low energies. A real theory is obtained by imposing suitable reality conditions. We also study the spherically-symmetric solution and show how the usual Reissner-Nordstrom solution is recovered.
Nonlinear electrodynamics is skilled with knots
NASA Astrophysics Data System (ADS)
Goulart, E.
2016-07-01
The aim of this letter is threefold: First is to show that nonlinear generalizations of electrodynamics support various types of knotted solutions in vacuum. The solutions are universal in the sense that they do not depend on the specific Lagrangian density, at least if the latter gives rise to a well-posed theory. Second, is to describe the interaction between probe waves and knotted background configurations. We show that the qualitative behaviour of this interaction may be described in terms of Robinson congruences, which appear explicitly in the causal structure of the theory. Finally, we argue that optical arrangements endowed with intense background fields could be the natural place to look for the knots experimentally.
Research on Orbital Plasma Electrodynamics (ROPE)
NASA Technical Reports Server (NTRS)
Intriligator, Devrie S.
1998-01-01
This final report summarizes some of the important scientific contributions to the Research on Orbital Plasma Electrodynamics (ROPE) investigation, to the Tethered Satellite System (TSS) mission, and to NASA that resulted from the work carried out under this contract at Carmel Research Center. These include Dr. Intriligator's participation in the PIT for the TSS-1R simulations and flight, her participation in ROPE team meetings and IWG meetings, her scientific analyses, and her writing and submitting technical papers to scientific journals. The scientific analyses concentrated on the characterization of energetic ions and their possible relation to pickup ion effects, correlation of particle and other effects (e.g., magnetic field, satellite surface), and collaboration with theorists including with ROPE co-investigators. In addition, scientific analyses were carried out of the effects due to satellite gas releases.
Plasma Motor Generator (PMG) electrodynamic tether experiment
NASA Technical Reports Server (NTRS)
Grossi, Mario D.
1995-01-01
The Plasma Motor Generator (PMG) flight of June 26, 1993 has been the most sophisticated and most successful mission that has been carried out thus far with an electrodynamic tether. Three papers from the Smithsonian Astrophysical Observatory, Washington, DC concerned with the PMG, submitted at the Fourth International Space Conference on Tethers in Space, in Washington, DC, in April 1995, are contained in this document. The three papers are (1) Electromagnetic interactions between the PMG tether and the magneto-ionic medium of the Ionosphere; (2) Tether-current-voltage characteristics, as determined by the Hollow Cathode Operation Modes; and (3) Hawaii-Hilo ground observations on the occasion for the PMG flight of June 23, 1993.
Quantum dot spectroscopy using cavity quantum electrodynamics.
Winger, Martin; Badolato, Antonio; Hennessy, Kevin J; Hu, Evelyn L; Imamoğlu, Ataç
2008-11-28
We show how cavity quantum electrodynamics using a tunable photonic crystal nanocavity in the strong-coupling regime can be used for single quantum dot spectroscopy. From the distinctive avoided crossings observed in the strongly coupled system we can identify the neutral and single positively charged exciton as well as the biexciton transitions. Moreover we are able to investigate the fine structure of those transitions and to identify a novel cavity mediated mixing of bright and dark exciton states, where the hyperfine interactions with lattice nuclei presumably play a key role. These results are enabled by a deterministic coupling scheme which allowed us to achieve unprecedented coupling strengths in excess of 150 microeV.
Maxwell electrodynamics subjected to quantum vacuum fluctuations
Gevorkyan, A. S.; Gevorkyan, A. A.
2011-06-15
The propagation of electromagnetic waves in the vacuum is considered taking into account quantum fluctuations in the limits of Maxwell-Langevin (ML) equations. For a model of 'white noise' fluctuations, using ML equations, a second order partial differential equation is found which describes the quantum distribution of virtual particles in vacuum. It is proved that in order to satisfy observed facts, the Lamb Shift etc, the virtual particles should be quantized in unperturbed vacuum. It is shown that the quantized virtual particles in toto (approximately 86 percent) are condensed on the 'ground state' energy level. It is proved that the extension of Maxwell electrodynamics with inclusion of the vacuum quantum field fluctuations may be constructed on a 6D space-time continuum with a 2D compactified subspace. Their influence on the refraction indexes of vacuum is studied.
Thermal quantum electrodynamics of nonrelativistic charged fluids.
Buenzli, Pascal R; Martin, Philippe A; Ryser, Marc D
2007-04-01
The theory relevant to the study of matter in equilibrium with the radiation field is thermal quantum electrodynamics (TQED). We present a formulation of the theory, suitable for nonrelativistic fluids, based on a joint functional integral representation of matter and field variables. In this formalism cluster expansion techniques of classical statistical mechanics become operative. They provide an alternative to the usual Feynman diagrammatics in many-body problems, which is not perturbative with respect to the coupling constant. As an application we show that the effective Coulomb interaction between quantum charges is partially screened by thermalized photons at large distances. More precisely one observes an exact cancellation of the dipolar electric part of the interaction, so that the asymptotic particle density correlation is now determined by relativistic effects. It still has the r(-6) decay typical for quantum charges, but with an amplitude strongly reduced by a relativistic factor.
Quantum-electrodynamics corrections in pionic hydrogen
Schlesser, S.; Le Bigot, E.-O.; Indelicato, P.; Pachucki, K.
2011-07-15
We investigate all pure quantum-electrodynamics corrections to the np{yields}1s, n=2-4 transition energies of pionic hydrogen larger than 1 meV, which requires an accurate evaluation of all relevant contributions up to order {alpha}{sup 5}. These values are needed to extract an accurate strong interaction shift from experiment. Many small effects, such as second-order and double vacuum polarization contribution, proton and pion self-energies, finite size and recoil effects are included with exact mass dependence. Our final value differs from previous calculations by up to {approx_equal}11 ppm for the 1s state, while a recent experiment aims at a 4 ppm accuracy.
Rail electrodynamics in a plasma armature railgun
NASA Astrophysics Data System (ADS)
Rolander, Glenn E.; Jamison, Keith A.; Villecco, Roger A.; Graham, Floyd R.
1991-08-01
Rail electrodynamics are investigated analytically by means of a model which relates rail motion to a transitory Lorentz force and the compressive restoration force. Local electric fields - generated by the magnetic field and the oscillation of the distance separating the rails - are examined to determine the extent of their influence on the laboratory frame and the projectile frame. When the projectile is accelerating, local voltage extremes are found to be related to the value of beta(t)p, with the maximums and minimums corresponding to even and odd multiples of pi, respectively. Based on these findings, rail displacements of about 2 mm are predicted for a railgun with a constant current of 2 MA. Certain criteria are proposed to minimize rail displacement and velocity and maximize the oscillation frequency. However, the model does not consider important effects such as deformation beyond the elastic regime.
Electrodynamic Dust Shield for Space Applications
NASA Technical Reports Server (NTRS)
Mackey, Paul J.; Johansen, Michael R.; Olsen, Robert C.; Raines, Matthew G.; Phillips, James R., III; Cox, Rachel E.; Hogue, Michael D.; Pollard, Jacob R. S.; Calle, Carlos I.
2016-01-01
Dust mitigation technology has been highlighted by NASA and the International Space Exploration Coordination Group (ISECG) as a Global Exploration Roadmap (GER) critical technology need in order to reduce life cycle cost and risk, and increase the probability of mission success. The Electrostatics and Surface Physics Lab in Swamp Works at the Kennedy Space Center has developed an Electrodynamic Dust Shield (EDS) to remove dust from multiple surfaces, including glass shields and thermal radiators. Further development is underway to improve the operation and reliability of the EDS as well as to perform material and component testing outside of the International Space Station (ISS) on the Materials on International Space Station Experiment (MISSE). This experiment is designed to verify that the EDS can withstand the harsh environment of space and will look to closely replicate the solar environment experienced on the Moon.
Electrodynamics of the Getaway Tether Experiment
NASA Technical Reports Server (NTRS)
Greene, Michael; Baginski, Michael; Wheelock, Douglas
1989-01-01
An electrodynamic circuit model of the interaction of a pair of small tethered satellites and the ionosphere is developed and analyzed. The system under study, the Getaway Tether Experiment (GATE), is composed of two small satellites and 1 km of insulated conducting tether. The nonlinear model has elements representing the emission, collection, and resistive flow of charge through an electrically conductive tether, plasma contactors, and the ionosphere. The circuit model is incorporated into a dynamic orbital simulation to predict mission performance. Simulation results show the feasibility to bilaterally transfer energy between stored electrical energy and orbital momentum. A transient model is also developed using the circuit model and a string of N lumped-parameter modules, each consisting of resistance, capacitance, and induced potential for the tether. Transients are shown via simulation to occur over millisecond intervals.
Electrodynamics of convection in the inner magnetosphere
NASA Technical Reports Server (NTRS)
Spiro, R. W.; Wolf, R. A.
1984-01-01
During the past ten years, substantial progress has been made in the development of quantitative models of convection in the magnetosphere and of the electrodynamic processes that couple that magnetosphere and ionosphere. Using a computational scheme first proposed by Vasyliunas, the convection models under consideration separate the three-dimensional problem of convection in the inner magnetosphere/ionosphere into a pair of two-dimensional problems coupled by Birkeland currents flowing between the two regions. The logic, development, and major results of the inner magnetosphere convection model are reviewed with emphasis on ionospheric and magnetospheric currents. A major theoretical result of the models has been the clarification of the relationship between the region 1/region 2 picture of field-aligned currents and the older partial ring current/tail current interruption picture of substorm dynamics.
Electrodynamics of the high-latitude mesosphere
NASA Technical Reports Server (NTRS)
Goldberg, Richard A.
1989-01-01
The discovery of apparent large (V/m) electric fields within the mesosphere suggests that this region is more active electrically than originally suspected. High-latitude observations have been particularly productive in developing new concepts regarding mesospheric electrodynamics. Several high-latitude observations of large mesospheric fields have been made under both quiet and aurorally active conditions but always below heights where enhanced ionizing radiations could significantly penetrate. Two measurements from Andoya, Norway, have also produced an anticorrelation of horizontal electric field directions with neutral wind velocities, leading to the theoretical description of a newly defined mechanism for V/m electric field generation involving wind-induced separation of charged aerosols. Evidence for mesospheric aerosols and winds exists at all latitudes but is most evident at high latitudes during the appearance of noctilucent and/or polar mesospheric clouds.
Enhancing nanoparticle electrodynamics with gold nanoplate mirrors.
Yan, Zijie; Bao, Ying; Manna, Uttam; Shah, Raman A; Scherer, Norbert F
2014-05-14
Mirrors and optical cavities can modify and enhance matter-radiation interactions. Here we report that chemically synthesized Au nanoplates can serve as micrometer-size mirrors that enhance electrodynamic interactions. Because of their plasmonic properties, the Au nanoplates enhance the brightness of scattered light from Ag nanoparticles near the nanoplate surface in dark-field microscopy. More importantly, enhanced optical trapping and optical binding of Ag nanoparticles are demonstrated in interferometric optical traps created from a single laser beam and its reflection from individual Au nanoplates. The enhancement of the interparticle force constant is ≈20-fold more than expected from the increased intensity due to standing wave interference. We show that the additional stability for optical binding arises from the restricted axial thermal motion of the nanoparticles that couples to and reduces the fluctuations in the lateral plane. This new mechanism greatly advances the photonic synthesis of ultrastable nanoparticle arrays and investigation of their properties.
A numerical simulation of auroral ionospheric electrodynamics
NASA Technical Reports Server (NTRS)
Mallinckrodt, A. J.
1985-01-01
A computer simulation of auroral ionospheric electrodynamics in the altitude range 80 to 250 km has been developed. The routine will either simulate typical electron precipitation profiles or accept observed data. Using a model background ionosphere, ion production rates are calculated from which equilibrium electron densities and the Hall and Pedersen conductivities may be determined. With the specification of suitable boundary conditions, the entire three-dimensional current system and electric field may be calculated within the simulation region. The results of the application of the routine to a typical inverted-V precipitation profile are demonstrated. The routine is used to explore the observed anticorrelation between electric field magnitude and peak energy in the precipitating electron spectrum of an auroral arc.
Thermal quantum electrodynamics of nonrelativistic charged fluids
NASA Astrophysics Data System (ADS)
Buenzli, Pascal R.; Martin, Philippe A.; Ryser, Marc D.
2007-04-01
The theory relevant to the study of matter in equilibrium with the radiation field is thermal quantum electrodynamics (TQED). We present a formulation of the theory, suitable for nonrelativistic fluids, based on a joint functional integral representation of matter and field variables. In this formalism cluster expansion techniques of classical statistical mechanics become operative. They provide an alternative to the usual Feynman diagrammatics in many-body problems, which is not perturbative with respect to the coupling constant. As an application we show that the effective Coulomb interaction between quantum charges is partially screened by thermalized photons at large distances. More precisely one observes an exact cancellation of the dipolar electric part of the interaction, so that the asymptotic particle density correlation is now determined by relativistic effects. It still has the r-6 decay typical for quantum charges, but with an amplitude strongly reduced by a relativistic factor.
Dusty Plasma Experiments Using an Electrodynamic Balance
NASA Technical Reports Server (NTRS)
Spann, J. F.; Abbas, M. M.; Suess, S. T.; Venturini, C. C.; Comfort, R. H.
2000-01-01
Knowledge of the formation, distribution, physical, chemical and optical characteristics of interstellar, interplanetary, and planetary dust grains provide valuable information about many issues dealing with the origin and formation of the solar system bodies, interplanetary and interstellar environments as well as various industrial processes. Understanding the microphysics of individual grains and their interaction with the surrounding environment is key to properly model various conditions and interpret existing data. The theory and models of individual dust grains are well developed for environments that vary from dense planetary atmospheres to dusty plasmas to diffuse environments such is interplanetary space. However, experimental investigations of individual dust grains in equilibrium are less common, perhaps due to the difficult of these experiments. Laboratory measurements of dust grains have primarily measured ensemble properties or transient properties of single grains. A technique developed in the 1950's for ion spectroscopy, known as a quadrupole trap or 'Paul Trap', has recently been used to investigate single micron-sized dust grains. This scaled ion trap called an electrodynamic balance has been used for atmospheric aerosol research. A description of this technique is provided. Recent results from experiments to investigate the equilibrium potential of dust grains exposed to far ultraviolet light or to -,in electron or ion beam are presented. This laboratory technique ]ends itself to many applications that relate to planetary atmospheres, heliospheric environments, pre-stellar and pre-planetary conditions, and industrial settings. Several planned experimental approaches are presented. Potential experiments to investigate the interaction of multiple dust grains using an electrodynamic balance are proposed.
Electrodynamics of ionospheric weather over low latitudes
NASA Astrophysics Data System (ADS)
Abdu, Mangalathayil Ali
2016-12-01
The dynamic state of the ionosphere at low latitudes is largely controlled by electric fields originating from dynamo actions by atmospheric waves propagating from below and the solar wind-magnetosphere interaction from above. These electric fields cause structuring of the ionosphere in wide ranging spatial and temporal scales that impact on space-based communication and navigation systems constituting an important segment of our technology-based day-to-day lives. The largest of the ionosphere structures, the equatorial ionization anomaly, with global maximum of plasma densities can cause propagation delays on the GNSS signals. The sunset electrodynamics is responsible for the generation of plasma bubble wide spectrum irregularities that can cause scintillation or even disruptions of satellite communication/navigation signals. Driven basically by upward propagating tides, these electric fields can suffer significant modulations from perturbation winds due to gravity waves, planetary/Kelvin waves, and non-migrating tides, as recent observational and modeling results have demonstrated. The changing state of the plasma distribution arising from these highly variable electric fields constitutes an important component of the ionospheric weather disturbances. Another, often dominating, component arises from solar disturbances when coronal mass ejection (CME) interaction with the earth's magnetosphere results in energy transport to low latitudes in the form of storm time prompt penetration electric fields and thermospheric disturbance winds. As a result, drastic modifications can occur in the form of layer restructuring (Es-, F3 layers etc.), large total electron content (TEC) enhancements, equatorial ionization anomaly (EIA) latitudinal expansion/contraction, anomalous polarization electric fields/vertical drifts, enhanced growth/suppression of plasma structuring, etc. A brief review of our current understanding of the ionospheric weather variations and the
Simulation Results Related to Stochastic Electrodynamics
NASA Astrophysics Data System (ADS)
Cole, Daniel C.
2006-01-01
Stochastic electrodynamics (SED) is a classical theory of nature advanced significantly in the 1960s by Trevor Marshall and Timothy Boyer. Since then, SED has continued to be investigated by a very small group of physicists. Early investigations seemed promising, as SED was shown to agree with quantum mechanics (QM) and quantum electrodynamics (QED) for a few linear systems. In particular, agreement was found for the simple harmonic electric dipole oscillator, physical systems composed of such oscillators and interacting electromagnetically, and free electromagnetic fields with boundary conditions imposed such as would enter into Casimir-type force calculations. These results were found to hold for both zero-point and non-zero temperature conditions. However, by the late 1970s and then into the early 1980s, researchers found that when investigating nonlinear systems, SED did not appear to provide agreement with the predictions of QM and QED. A proposed reason for this disagreement was advocated by Boyer and Cole that such nonlinear systems are not sufficiently realistic for describing atomic and molecular physical systems, which should be fundamentally based on the Coulombic binding potential. Analytic attempts on these systems have proven to be most difficult. Consequently, in recent years more attention has been placed on numerically simulating the interaction of a classical electron in a Coulombic binding potential, with classical electromagnetic radiation acting on the classical electron. Good agreement was found for this numerical simulation work as compared with predictions from QM. Here this worked is reviewed and possible directions are discussed. Recent simulation work involving subharmonic resonances for the classical hydrogen atom is also discussed; some of the properties of these subharmonic resonances seem quite interesting and unusual.
Macroscopic test of quantum mechanics versus stochastic electrodynamics
NASA Astrophysics Data System (ADS)
Chaturvedi, S.; Drummond, Peter D.
1997-02-01
We identify a test of quantum mechanics versus macroscopic local realism in the form of stochastic electrodynamics. The test uses the steady-state triple quadrature correlations of a parametric oscillator below threshold.
An Experiment on the Limits of Quantum Electro-dynamics
DOE R&D Accomplishments Database
Barber, W. C.; Richter, B.; Panofsky, W. K. H.; O'Neill, G. K.; Gittelman, B.
1959-06-01
The limitations of previously performed or suggested electrodynamic cutoff experiments are reviewed, and an electron-electron scattering experiment to be performed with storage rings to investigate further the limits of the validity of quantum electrodynamics is described. The foreseen experimental problems are discussed, and the results of the associated calculations are given. The parameters and status of the equipment are summarized. (D.C.W.)
Exact asymptotic form for the {beta} function in quantum electrodynamics
Suslov, I. M.
2009-06-15
It is shown that the asymptotic form of the Gell-Mann-Low function in quantum electrodynamics can be determined exactly: {beta}(g) = g for g {sup {yields}} {infinity}, where g = e{sup 2} is the running fine-structure constant. This solves the problem of electrodynamics at small distances L (for which dependence g {infinity} L{sup -2} holds) and completely eliminates the problem of 'zero charge.'.
Quantum Electrodynamics Effects in Heavy Ions and Atoms
Shabaev, V. M.; Andreev, O. V.; Bondarev, A. I.; Glazov, D. A.; Kozhedub, Y. S.; Maiorova, A. V.; Tupitsyn, I. I.; Plunien, G.; Volotka, A. V.
2011-05-11
Quantum electrodynamics theory of heavy ions and atoms is considered. The current status of calculations of the binding energies, the hyperfine splitting and g factor values in heavy few-electron ions is reviewed. The theoretical predictions are compared with available experimental data. A special attention is focused on tests of quantum electrodynamics in strong electromagnetic fields and on determination of the fundamental constants. Recent progress in calculations of the parity nonconservation effects with heavy atoms and ions is also reported.
Electrodynamic forces in tethered satellite systems. Part 1: System control
NASA Astrophysics Data System (ADS)
Netzer, Ehud; Kane, Thomas R.
1994-10-01
Part 1 of this work deals with the use of electrodynamic forces for control of tethered satellite system. A system formed by two massive end-bodies connected to each other by a current carrying tether is to be kept in an earth-pointing orientation by means of joint actions of thrusters on one of the end-bodies and electrodynamic forces acting on the tether.
Electrodynamics of long metallic tethers in the ionospheric plasma
NASA Technical Reports Server (NTRS)
Dobrowolny, M.
1978-01-01
A study is presented of the electrodynamic interactions of long metallic tethers (lengths up to 100 km) with the ionospheric plasma. The study, which is of interest in view of possible future experiments using long tethers in space, includes the derivation of current and potential distribution along the tether, taking also the effects of internal resistance into account. Electrostatic and electrodynamic drag forces are computed and compared with aerodynamic drag.
Change in the coil distribution of electrodynamic suspension system
NASA Technical Reports Server (NTRS)
Tanaka, Hisashi
1992-01-01
At the Miyazaki Maglev Test Center, the initial test runs were completed using a system design that required the superconducting coils to be parallel with the ground levitation coils. Recently, the coil distribution was changed to a system such that the two types of coils were perpendicular to each other. Further system changes will lead to the construction of a side wall levitation system. It is hoped that the development will culminate in a system whereby a superconducting coil will maintain all the functions: levitation, propulsion, and guidance.
Yang, Jun; Zolotas, Argyrios; Chen, Wen-Hua; Michail, Konstantinos; Li, Shihua
2011-07-01
Robust control of a class of uncertain systems that have disturbances and uncertainties not satisfying "matching" condition is investigated in this paper via a disturbance observer based control (DOBC) approach. In the context of this paper, "matched" disturbances/uncertainties stand for the disturbances/uncertainties entering the system through the same channels as control inputs. By properly designing a disturbance compensation gain, a novel composite controller is proposed to counteract the "mismatched" lumped disturbances from the output channels. The proposed method significantly extends the applicability of the DOBC methods. Rigorous stability analysis of the closed-loop system with the proposed method is established under mild assumptions. The proposed method is applied to a nonlinear MAGnetic LEViation (MAGLEV) suspension system. Simulation shows that compared to the widely used integral control method, the proposed method provides significantly improved disturbance rejection and robustness against load variation.
A novel permanent maglev impeller TAH: most requirements on blood pumps have been satisfied.
Qian, K X; Zeng, P; Ru, W M; Yuan, H Y
2003-07-01
Based on the development of an impeller total artificial heart (TAH) (1987) and a permanent maglev (magnetic levitation) impeller pump (2002), as well as a patented magnetic bearing and magnetic spring (1996), a novel permanent maglev impeller TAH has been developed. The device consists of a rotor and a stator. The rotor is driven radially. Two impellers with different dimensions are fixed at both the ends of the rotor. The levitation of the rotor is achieved by using two permanent magnetic bearings, which have double function: radial bearing and axial spring. As the rotor rotates at a periodic changing speed, two pumps deliver the pulsatile flow synchronously. The volume balance between the two pumps is realized due to self-modulation property of the impeller pumps, without need for detection and control. Because the hemo-dynamic force acting on the left impeller is larger than that on the right impeller, and this force during systole is larger than that during diastole, the rotor reciprocates axially once a cycle. This is beneficial to prevent the thrombosis in the pump. Furthermore, a small flow via the gap between stator and rotor from left pump into right pump comes to a full washout in the motor and the pumps. Therefore, it seems neither mechanical wear nor thrombosis could occur. The previously developed prototype impeller TAH had demonstrated that it could operate in animal experiments indefinitely, if the bearing would not fail to work. Expectantly, this novel permanent magnetic levitation impeller TAH with simplicity, implantability, pulsatility, compatibility and durability has satisfied the most requirements on blood pumps and will have more extensive applications in experiments and clinics.
Conductive Tether Coating for Electrodynamic Tethers
NASA Technical Reports Server (NTRS)
Vaughn, Jason A.; Schuler, Pete
2000-01-01
The Propulsive Small Expendable Deployer System (ProSEDS), which is an on-orbit demonstration of the propulsion capabilities of electrodynamic tethers in space, is a secondary payload on a Delta 11 unmanned expendable booster. The ProSEDS tether consists of a 5 km bare electrodynamic tether and a 1 0-km non-conductive leader tether. Near the Delta 11, 160 m of the conductive tether is insulated to prevent plasma electron collection from the plasma contactor and for other science requirements. The remainder of the 5-km conductive tether is coated with a new conductive coating to collect plasma electrons. A bare metal tether easily collects electrons from the plasma, but thermal concerns preclude this design. A highly emissive conductive polymer developed by Triton Systems, Inc. has been optimized for both conductivity and thermo-optical properties. The current design for the ProSEDS conductive tether is seven individually coated strands of 28 AWG aluminum wire, coated with an atomic oxygen-resistant conductive polymer composed of a mixture of COR (Colorless Oxygen Resistant) and polyanaline (PANI) known as C-COR (Conductive-Colorless Oxygen Resistant). The conductive-coated wire strands are cold-welded to individually coated strands of the insulated tether. The insulated tether is coated with 1 mil of polyimide and an atomic oxygen resistant polymer TOR-BP. The insulated tether must stand off the entire voltage of the tether (1 200 V) at various times during the mission. All seven wires are twisted around a Kevlar-29 core using the Hi-wire design. Extensive testing has been performed at the Marshall Space Flight Center to qualify both the conductive coating and insulating coating for use on the ProSEDS tether. The conductive coating has been exposed to a plasma to verify the coatings ability to collect electrons from the space plasma from 0 to 1500 V, and to verify the coatings ability to collect electrons after atomic oxygen exposure. The insulated coating has been
Groh, K.R.
1993-01-01
This study examined the effects on pineal function of magnetic field (MF) exposures (ac and dc components) similar to those produced by the TransRapid TR-07 and other electromagnetic maglev systems (EMS). Rats were entrained to a light-dark cycle and then exposed to a continuous, or to an inverted, intermittent (on = 45 s, off = 15 s, induced current = 267 G/s) simulated multifrequency ac and dc magnetic field (MF) at 1 or 7 times the TR-07 maglev vehicle MF intensity for 2 hr. Other groups of rats were exposed to only the ac or the dc-component of the maglev MF. For comparison, one group was exposed to an inverted, intermittent 60-Hz MF. Each group was compared to an unexposed group of rats for changes in pineal melatonin and serotonin-N-acetyltransferase (NAT). MF exposures at an intensity equivalent to that produced by the TR-07 vehicle had no effect on melatonin or NAT compared with sham-exposed animals under any of the conditions examined. However, 7X TR-07-level continuous 2-h MF exposures significantly depressed pineal NAT by 45%. Pineal melatonin was also depressed 33--43% by a continuous 7X TR-07 MF exposure and 28% by an intermittent 60-Hz 850-mG MF, but the results were not statically significant. This study demonstrates that intermittent, combined ac and dc MFs similar to those produced by the TR-07 EMS maglev vehicle alter the normal circadian rhythm of pineal indoleamine metabolism. The pineal regulatory enzyme NAT was more sensitive to MF exposure than melatonin and may be a more desirable measure of the biological effects of MF exposure.
Groh, K.R.
1993-06-01
This study examined the effects on pineal function of magnetic field (MF) exposures (ac and dc components) similar to those produced by the TransRapid TR-07 and other electromagnetic maglev systems (EMS). Rats were entrained to a light-dark cycle and then exposed to a continuous, or to an inverted, intermittent (on = 45 s, off = 15 s, induced current = 267 G/s) simulated multifrequency ac and dc magnetic field (MF) at 1 or 7 times the TR-07 maglev vehicle MF intensity for 2 hr. Other groups of rats were exposed to only the ac or the dc-component of the maglev MF. For comparison, one group was exposed to an inverted, intermittent 60-Hz MF. Each group was compared to an unexposed group of rats for changes in pineal melatonin and serotonin-N-acetyltransferase (NAT). MF exposures at an intensity equivalent to that produced by the TR-07 vehicle had no effect on melatonin or NAT compared with sham-exposed animals under any of the conditions examined. However, 7X TR-07-level continuous 2-h MF exposures significantly depressed pineal NAT by 45%. Pineal melatonin was also depressed 33--43% by a continuous 7X TR-07 MF exposure and 28% by an intermittent 60-Hz 850-mG MF, but the results were not statically significant. This study demonstrates that intermittent, combined ac and dc MFs similar to those produced by the TR-07 EMS maglev vehicle alter the normal circadian rhythm of pineal indoleamine metabolism. The pineal regulatory enzyme NAT was more sensitive to MF exposure than melatonin and may be a more desirable measure of the biological effects of MF exposure.
Electrodynamic Dust Shield for Space Applications
NASA Technical Reports Server (NTRS)
Mackey, P. J.; Johansen, M. R.; Olsen, R. C.; Raines, M. G.; Phillips, J. R., III; Pollard, J. R. S.; Calle, C. I.
2016-01-01
The International Space Exploration Coordination Group (ISECG) has chosen dust mitigation technology as a Global Exploration Roadmap (GER) critical technology need in order to reduce life cycle cost and risk, and increase the probability of mission success. NASA has also included Particulate Contamination Prevention and Mitigation as a cross-cutting technology to be developed for contamination prevention, cleaning and protection. This technology has been highlighted due to the detrimental effect of dust on both human and robotic missions. During manned Apollo missions, dust caused issues with both equipment and crew. Contamination of equipment caused many issues including incorrect instrument readings and increased temperatures due to masking of thermal radiators. The astronauts were directly affected by dust that covered space suits, obscured face shields and later propagated to the cabin and into the crew's eyes and lungs. Robotic missions on Mars were affected when solar panels were obscured by dust thereby reducing the effectiveness of the solar panels. The Electrostatics and Surface Physics Lab in Swamp Works at the Kennedy Space Center has been developing an Electrodynamic Dust Shield (EDS) to remove dust from multiple surfaces, including glass shields and thermal radiators. This technology has been tested in lab environments and has evolved over several years. Tests of the technology include reduced gravity flights (one-sixth g) in which Apollo Lunar dust samples were successfully removed from glass shields while under vacuum (10(exp -6) kPa).
Pole-factorization theorem in quantum electrodynamics
Stapp, H.P.
1996-01-01
In quantum electrodynamics a classical part of the S-matrix is normally factored out in order to obtain a quantum remainder that can be treated perturbatively without the occurrence of infrared divergences. However, this separation, as usually performed, introduces spurious large-distance effects that produce an apparent breakdown of the important correspondence between stable particles and poles of the S-matrix, and, consequently, lead to apparent violations of the correspondence principle and to incorrect results for computations in the mesoscopic domain lying between the atomic and classical regimes. An improved computational technique is described that allows valid results to be obtained in this domain, and that leads, for the quantum remainder, in the cases studied, to a physical-region singularity structure that, as regards the most singular parts, is the same as the normal physical-region analytic structure in theories in which all particles have non-zero mass. The key innovations here are to define the classical part in coordinate space, rather than in momentum space, and to define there a separation of the photon-electron coupling into its classical and quantum parts that has the following properties: (1) The contributions from the terms containing only classical couplings can be summed to all orders to give a unitary operator that generates the coherent state that corresponds to the appropriate classical process, and (2) The quantum remainder can be rigorously shown to exhibit, as regards its most singular parts, the normal analytic structure. 22 refs.
Circuit quantum electrodynamics with a spin qubit.
Petersson, K D; McFaul, L W; Schroer, M D; Jung, M; Taylor, J M; Houck, A A; Petta, J R
2012-10-18
Electron spins trapped in quantum dots have been proposed as basic building blocks of a future quantum processor. Although fast, 180-picosecond, two-quantum-bit (two-qubit) operations can be realized using nearest-neighbour exchange coupling, a scalable, spin-based quantum computing architecture will almost certainly require long-range qubit interactions. Circuit quantum electrodynamics (cQED) allows spatially separated superconducting qubits to interact via a superconducting microwave cavity that acts as a 'quantum bus', making possible two-qubit entanglement and the implementation of simple quantum algorithms. Here we combine the cQED architecture with spin qubits by coupling an indium arsenide nanowire double quantum dot to a superconducting cavity. The architecture allows us to achieve a charge-cavity coupling rate of about 30 megahertz, consistent with coupling rates obtained in gallium arsenide quantum dots. Furthermore, the strong spin-orbit interaction of indium arsenide allows us to drive spin rotations electrically with a local gate electrode, and the charge-cavity interaction provides a measurement of the resulting spin dynamics. Our results demonstrate how the cQED architecture can be used as a sensitive probe of single-spin physics and that a spin-cavity coupling rate of about one megahertz is feasible, presenting the possibility of long-range spin coupling via superconducting microwave cavities.
PT-symmetric quantum electrodynamics and unitarity.
Milton, Kimball A; Abalo, E K; Parashar, Prachi; Pourtolami, Nima; Wagner, J
2013-04-28
More than 15 years ago, a new approach to quantum mechanics was suggested, in which Hermiticity of the Hamiltonian was to be replaced by invariance under a discrete symmetry, the product of parity and time-reversal symmetry, PT. It was shown that, if PT is unbroken, energies were, in fact, positive, and unitarity was satisfied. Since quantum mechanics is quantum field theory in one dimension--time--it was natural to extend this idea to higher-dimensional field theory, and in fact an apparently viable version of PT-invariant quantum electrodynamics (QED) was proposed. However, it has proved difficult to establish that the unitarity of the scattering matrix, for example, the Källén spectral representation for the photon propagator, can be maintained in this theory. This has led to questions of whether, in fact, even quantum mechanical systems are consistent with probability conservation when Green's functions are examined, since the latter have to possess physical requirements of analyticity. The status of PT QED will be reviewed in this paper, as well as the general issue of unitarity.
Implementing quantum electrodynamics with ultracold atomic systems
NASA Astrophysics Data System (ADS)
Kasper, V.; Hebenstreit, F.; Jendrzejewski, F.; Oberthaler, M. K.; Berges, J.
2017-02-01
We discuss the experimental engineering of model systems for the description of quantum electrodynamics (QED) in one spatial dimension via a mixture of bosonic 23Na and fermionic 6Li atoms. The local gauge symmetry is realized in an optical superlattice, using heteronuclear boson–fermion spin-changing interactions which preserve the total spin in every local collision. We consider a large number of bosons residing in the coherent state of a Bose–Einstein condensate on each link between the fermion lattice sites, such that the behavior of lattice QED in the continuum limit can be recovered. The discussion about the range of possible experimental parameters builds, in particular, upon experiences with related setups of fermions interacting with coherent samples of bosonic atoms. We determine the atomic system’s parameters required for the description of fundamental QED processes, such as Schwinger pair production and string breaking. This is achieved by benchmark calculations of the atomic system and of QED itself using functional integral techniques. Our results demonstrate that the dynamics of one-dimensional QED may be realized with ultracold atoms using state-of-the-art experimental resources. The experimental setup proposed may provide a unique access to longstanding open questions for which classical computational methods are no longer applicable.
Electrodynamic arrow of time and cosmology
NASA Astrophysics Data System (ADS)
Radecke, Hans-Dieter
Simplified mathematical models were used for the examination of the relationship between the arrows of time of electrodynamics and cosmology. The model of a 1-D harmonic oscillator, coupled to a scalar field, was first used. The combined system of coupled differential equations could be exactly resolved and allowed an examination of the field solution type, with regard to retard and advance in the framework of the cosmological geometry of the standard model, by which a closed universe was taken as a basis. It was shown that the oscillation radiation was clearly retarded at the big bang, and clearly advanced at the final explosion. In order to interpolate between these asymptotical boundary values, it was necessary to consider the radiation absorption of the cosmical medium. The general behavior of the considered system solutions showed that only the retarded radiation prevailed at big bang. Because of the cosmical absorption, its amplitude was completely attenuated to zero, before the universe heat death was installed. The advanced field amplitude is to be preceived after the universe contraction beginning and swings to a maximal value which is reached at the final explosion.
Dark aspects of massive spinor electrodynamics
NASA Astrophysics Data System (ADS)
Kim, Edward J.; Kouwn, Seyen; Oh, Phillial; Park, Chan-Gyung
2014-07-01
We investigate the cosmology of massive spinor electrodynamics when torsion is non-vanishing. A non-minimal interaction is introduced between the torsion and the vector field and the coupling constant between them plays an important role in subsequential cosmology. It is shown that the mass of the vector field and torsion conspire to generate dark energy and pressureless dark matter, and for generic values of the coupling constant, the theory effectively provides an interacting model between them with an additional energy density of the form ~ 1/a6. The evolution equations mimic ΛCDM behavior up to 1/a3 term and the additional term represents a deviation from ΛCDM. We show that the deviation is compatible with the observational data, if it is very small. We find that the non-minimal interaction is responsible for generating an effective cosmological constant which is directly proportional to the mass squared of the vector field and the mass of the photon within its current observational limit could be the source of the dark energy.
Zhang, Dapeng; Long, Zhiqiang; Xue, Song; Zhang, Junge
2012-01-01
This paper studies an absolute positioning sensor for a high-speed maglev train and its fault diagnosis method. The absolute positioning sensor is an important sensor for the high-speed maglev train to accomplish its synchronous traction. It is used to calibrate the error of the relative positioning sensor which is used to provide the magnetic phase signal. On the basis of the analysis for the principle of the absolute positioning sensor, the paper describes the design of the sending and receiving coils and realizes the hardware and the software for the sensor. In order to enhance the reliability of the sensor, a support vector machine is used to recognize the fault characters, and the signal flow method is used to locate the faulty parts. The diagnosis information not only can be sent to an upper center control computer to evaluate the reliability of the sensors, but also can realize on-line diagnosis for debugging and the quick detection when the maglev train is off-line. The absolute positioning sensor we study has been used in the actual project.
Zhang, Dapeng; Long, Zhiqiang; Xue, Song; Zhang, Junge
2012-01-01
This paper studies an absolute positioning sensor for a high-speed maglev train and its fault diagnosis method. The absolute positioning sensor is an important sensor for the high-speed maglev train to accomplish its synchronous traction. It is used to calibrate the error of the relative positioning sensor which is used to provide the magnetic phase signal. On the basis of the analysis for the principle of the absolute positioning sensor, the paper describes the design of the sending and receiving coils and realizes the hardware and the software for the sensor. In order to enhance the reliability of the sensor, a support vector machine is used to recognize the fault characters, and the signal flow method is used to locate the faulty parts. The diagnosis information not only can be sent to an upper center control computer to evaluate the reliability of the sensors, but also can realize on-line diagnosis for debugging and the quick detection when the maglev train is off-line. The absolute positioning sensor we study has been used in the actual project. PMID:23112619
Lin, Zhuchong; Liu, Kun; Zhang, Li; Zeng, Delin
2016-09-01
Maglev dual-stage inertially stabilization (MDIS) system is a newly proposed system which combines a conventional two-axis gimbal assembly and a 5-DOF (degree of freedom) magnetic bearing with vernier tilting capacity to perform dual-stage stabilization for the LOS of the suspended optical instrument. Compared with traditional dual-stage system, maglev dual-stage system exhibits different characteristics due to the negative position stiffness of the magnetic forces, which introduces additional coupling in the dual stage control system. In this paper, the coupling effect on the system performance is addressed based on frequency-domain analysis, including disturbance rejection, fine stage saturation and coarse stage structural resonance suppression. The difference between various control strategies is also discussed, including pile-up(PU), stabilize-follow (SF) and stabilize-compensate (SC). A number of principles for the design of a maglev dual stage system are proposed. A general process is also suggested, which leads to a cost-effective design striking a balance between high performance and complexity. At last, a simulation example is presented to illustrate the arguments in the paper.
Unified modelling of passive homopolar and heteropolar electrodynamic bearings
NASA Astrophysics Data System (ADS)
Detoni, J. G.; Impinna, F.; Tonoli, A.; Amati, N.
2012-09-01
A model of passive electrodynamic bearings based on the R-L dynamics of the eddy currents inside a conductor is presented. The model is derived from an analytical solution of the magnetic field in the air region surrounding the rotor for electrodynamic bearings having an even number of magnetic pole pairs. It allows homopolar and heteropolar electrodynamic bearings to be considered in a single unified way that accounts for the electromechanical interactions between the rotating conductor and the magnetic field of the stator. The model of the bearings is then coupled to a Jeffcott rotor model using complex coordinates in a state-space representation, allowing the dynamics of rotors supported by electrodynamic bearings to be studied. The number of magnetic pole pairs is found to influence rotordynamic stability, unbalance responses and frequency responses. The results demonstrate that homopolar electrodynamic bearings have a unique characteristic of passively filtering the transmission of forces due to residual unbalance of the rotor to the machine supports. The models are also used to perform a stability analysis of a case study presented in literature, and results from experimental observation are compared to those obtained analytically.
Propulsion and Levitation with a Large Electrodynamic Wheel
NASA Astrophysics Data System (ADS)
Gaul, Nathan; Lane, Hannah
We constructed an electrodynamic wheel using a motorized bicycle wheel with a radius of 12 inches and 36 one-inch cube magnets attached to the rim of the wheel. The radial magnetic field on the outside of the wheel was maximized by arranging the magnets into a series of Halbach arrays which amplify the field on one side of the array and reduce it on the other side. Rotating the wheel produces a rapidly oscillating magnetic field. When a conductive metal ``track'' is placed in this area of strong magnetic flux, eddy currents are produced in the track. These eddy currents create magnetic fields that interact with the magnetic fields from the electrodynamic wheel. The interaction of the magnetic fields produces lift and drag forces on the track which were measured with force gauges. Measurements were taken at a variety of wheel speeds, and the results were compared to the theoretical prediction that there should be a linear relationship between the lift and drag forces with increasing wheel speed. Partial levitation was achieved with the current electrodynamic wheel. In the future, the wheel will be upgraded to include 72 magnets rather than 36 magnets. This will double the frequency at which the magnetic field oscillates, increasing the magnetic flux. Electrodynamic wheels have applications to the transportation industry, since multiple electrodynamic wheels could be used on a vehicle to produce a lift and propulsion force over a conductive track.
Emergent Electrodynamics of Skyrmions in Chiral Magnets
NASA Astrophysics Data System (ADS)
Pfleiderer, Christian
2013-03-01
Skyrmions are particle-like states of continuous fields named after the English particle physicist Tony Skyrme. Their existence has long been considered in nuclear matter, quantum Hall systems, liquid crystals, superfluid 3He and ultracold atoms. As their defining property they support a topological winding number of 1. In magnetic materials spin configurations with a non-vanishing topological winding number, driven by the interplay of magnetic anisotropies, dipolar interactions and geometrical frustration, have been known for a long time. This is contrasted by the recent discovery of skyrmion lattices in chiral magnets, i.e., long-range magnetic order in which each magnetic unit cell contains a skyrmion and thus a non-zero winding number. As a practical consequence, the non-zero topological winding number implies that the conduction electrons in the presence of a skyrmion experience changes of Berry phase, that correspond precisely to one quantum of emergent magnetic flux. In transport measurements this leads directly to a topological Hall signal. Moreover, tiny electric current densities are already sufficient to generate a motion of the skyrmions first observed indirectly in neutron scattering. Since each skyrmion supports one quantum of emergent magnetic flux the motion of the skyrmions induces an emergent electric field consistent with Faradays law of induction that may also be observed experimentally. The excellent theoretical description of the skyrmion lattices observed so far in metals, doped semiconductors and insulators suggests that they represent a rather universal phenomenon to be expected in a wide range of systems supporting chiral spin interactions. Taken together with the first insights into their emergent electrodynamics, skyrmion lattices in chiral magnets develop into a new area of condensed matter magnetism offering insights relevant for applications.
Introduction to electrodynamics for microwave linear accelerators
Whittum, D.H.
1998-04-01
This collection of notes and exercises is intended as a workbook to introduce the principles of microwave linear accelerators, starting with the underlying foundation in electrodynamics. The author reviewed Maxwell's equations, the Lorentz force law, and the behavior of fields near a conducting boundary. The author goes on to develop the principles of microwave electronics, including waveguide modes, circuit equivalence, shunt admittance of an iris, and voltage standing-wave ratio. The author constructed an elementary example of a waveguide coupled to a cavity, and examined its behavior during transient filling of the cavity, and in steady-state. He goes on to examine a periodic line. Then he examined the problem of acceleration in detail, studying first the properties of a single cavity-waveguide-beam system and developing the notions of wall Q, external Q, [R/Q], shunt impedance, and transformer ratio. He then examined the behavior of such a system on and off resonance, on the bench, and under conditions of transient and steady-state beam-loading. This work provides the foundation for the commonly employed circuit equivalents and the basic scalings for such systems. Following this he examined the coupling of two cavities, powered by a single feed, and goes on to consider structures constructed from multiple coupled cavities. The basic scalings for constant impedance and constant gradient traveling-wave structures are set down, including features of steady-state beam-loading, and the coupled-circuit model. Effects of uniform and random detuning are derived. These notes conclude with a brief outline of some problems of current interest in accelerator research.
Circuit quantum electrodynamics with a spin qubit
NASA Astrophysics Data System (ADS)
Petersson, Karl
2013-03-01
Electron spins in quantum dots have been proposed as the building blocks of a quantum information processor. While both fast one and two qubit operations have been demonstrated, coupling distant spins remains a daunting challenge. In contrast, circuit quantum electrodynamics (cQED) has enabled superconducting qubits to be readily coupled over large distances via a superconducting microwave cavity. I will present our recent work aimed at integrating spin qubits with the cQED architecture.[2] Our approach is to use spin qubits formed in strong spin-orbit materials such as InAs nanowires to enable a large effective coupling of the spin to the microwave cavity field. For an InAs nanowire double quantum dot coupled to the superconducting microwave cavity we achieve a charge-cavity coupling rate of ~ 30 MHz. Combining this large charge-cavity coupling rate with electrically driven spin qubit rotations we demonstrate that the cQED architecture can be used a sensitive probe of single spin dynamics. In another experiment, we can apply a source-drain bias to drive current through the double quantum dot and observe gain in the cavity transmission. We additionally measure photon emission from the cavity without any input field applied. Our results suggest that long-range spin coupling via superconducting microwave cavities is feasible and present new avenues for exploring quantum optics on a chip. Research was performed in collaboration with Will McFaul, Michael Schroer, Minkyung Jung, Jake Taylor, Andrew Houck and Jason Petta. We acknowledge support from the Sloan and Packard Foundations, Army Research Office, and DARPA QuEST.
On SL(2,R) symmetry in nonlinear electrodynamics theories
NASA Astrophysics Data System (ADS)
Babaei Velni, Komeil; Babaei-Aghbolagh, H.
2016-12-01
Recently, it has been observed that the Noether-Gaillard-Zumino (NGZ) identity holds order by order in α‧ expansion in nonlinear electrodynamics theories as Born-Infeld (BI) and Bossard-Nicolai (BN). The nonlinear electrodynamics theory that couples to an axion field is invariant under the SL (2 , R) duality in all orders of α‧ expansion in the Einstein frame. In this paper we show that there are the SL (2 , R) invariant forms of the energy momentum tensors of axion-nonlinear electrodynamics theories in the Einstein frame. These SL (2 , R) invariant structures appear in the energy momentum tensors of BI and BN theories at all orders of α‧ expansion. The SL (2 , R) symmetry appears in the BI and BN Lagrangians as a multiplication of Maxwell Lagrangian and a series of SL (2 , R) invariant structures.
Photon physics: from wave mechanics to quantum electrodynamics
NASA Astrophysics Data System (ADS)
Keller, Ole
2009-05-01
When rewritten in an appropriate manner, the microscopic Maxwell-Lorentz equations appear as a wave-mechanical theory for photons, and their quantum physical interaction with matter. A natural extension leads from photon wave mechanics to quantum electrodynamics (QED). In its modern formulation photon wave mechanics has given us valuable new insight in subjects such as spatial photon localization, near-field photon dynamics, transverse photon mass, photon eikonal theory, photon tunneling, and rim-zone electrodynamics. The present review is based on my plenary lecture at the SPIE-Europe 2009 Optics and Optoelectronics International Symposium in Prague.
Optical-lattice Hamiltonians for relativistic quantum electrodynamics
Kapit, Eliot; Mueller, Erich
2011-03-15
We show how interpenetrating optical lattices containing Bose-Fermi mixtures can be constructed to emulate the thermodynamics of quantum electrodynamics (QED). We present models of neutral atoms on lattices in 1+1, 2+1, and 3+1 dimensions whose low-energy effective action reduces to that of photons coupled to Dirac fermions of the corresponding dimensionality. We give special attention to (2+1)-dimensional quantum electrodynamics (QED3) and discuss how two of its most interesting features, chiral symmetry breaking and Chern-Simons physics, could be observed experimentally.
Engineering squeezed states of microwave radiation with circuit quantum electrodynamics
Li Pengbo; Li Fuli
2011-03-15
We introduce a squeezed state source for microwave radiation with tunable parameters in circuit quantum electrodynamics. We show that when a superconducting artificial multilevel atom interacting with a transmission line resonator is suitably driven by external classical fields, two-mode squeezed states of the cavity modes can be engineered in a controllable fashion from the vacuum state via adiabatic following of the ground state of the system. This scheme appears to be robust against decoherence and is realizable with present techniques in circuit quantum electrodynamics.
Wilson fermions and axion electrodynamics in optical lattices.
Bermudez, A; Mazza, L; Rizzi, M; Goldman, N; Lewenstein, M; Martin-Delgado, M A
2010-11-05
We show that ultracold Fermi gases in optical superlattices can be used as quantum simulators of relativistic lattice fermions in 3+1 dimensions. By exploiting laser-assisted tunneling, we find an analogue of the so-called naive Dirac fermions, and thus provide a realization of the fermion doubling problem. Moreover, we show how to implement Wilson fermions, and discuss how their mass can be inverted by tuning the laser intensities. In this regime, our atomic gas corresponds to a phase of matter where Maxwell electrodynamics is replaced by axion electrodynamics: a 3D topological insulator.
Time-dependent Kohn-Sham approach to quantum electrodynamics
Ruggenthaler, M.; Mackenroth, F.; Bauer, D.
2011-10-15
We prove a generalization of the van Leeuwen theorem toward quantum electrodynamics, providing the formal foundations of a time-dependent Kohn-Sham construction for coupled quantized matter and electromagnetic fields. We circumvent the symmetry-causality problems associated with the action-functional approach to Kohn-Sham systems. We show that the effective external four-potential and four-current of the Kohn-Sham system are uniquely defined and that the effective four-current takes a very simple form. Further we rederive the Runge-Gross theorem for quantum electrodynamics.
Feedback between neutral winds and auroral arc electrodynamics
NASA Technical Reports Server (NTRS)
Lyons, L. R.; Walterscheid, R. L.
1986-01-01
The feedback between neutral atmospheric winds and the electrodynamics of a stable, discrete auroral arc is analyzed. The ionospheric current continuity equation and the equation for neutral gas acceleration by ion drag are solved simultaneously, as a function of time. The results show that, in general, the electric field in the ionosphere adjusts to neutral wind acceleration so as to keep auroral field-aligned currents and electron acceleration approximately independent of time. It is thus concluded that the neutral winds that develop as a result of the electrodynamical forcing associated with an arc do not significantly affect the intensity of the arc.
Spin- and velocity-dependent nonrelativistic potentials in modified electrodynamics
NASA Astrophysics Data System (ADS)
de Brito, G. P.; Malta, P. C.; Ospedal, L. P. R.
2017-01-01
We investigate the interparticle potential between spin-0, spin-1 /2 , and spin-1 sources interacting in modified electrodynamics in the nonrelativistic regime. By keeping terms of O (|p |2/m2) in the amplitudes, we obtain spin- and velocity-dependent interaction energies. We find well-known effects such as spin-orbit couplings, as well as spin-spin (dipole-dipole) interactions. For concreteness, we consider the cases of electrodynamics with higher derivatives (Podolsky-Lee-Wick) and hidden photons.
Nonlinear electrodynamics of high-temperature superconductors
NASA Astrophysics Data System (ADS)
Zutic, Igor
We investigate the effects of nonlinear electrodynamics in unconventional superconductors. These effects can serve as fingerprints to identify the symmetry of the superconducting pairing state and to provide information about the unknown pairing mechanism in High Temperature Superconductors (HTSC). In the Meissner regime, at low temperatures, a nonlinear magnetic response arises from the presence of lines on the Fermi surface where the superconducting energy gap is very small or zero. This can be used to perform "node spectroscopy", that is, as a sensitive bulk probe to locate the angular position of those lines. We first compute the nonlinear magnetic moment as a function of applied field and geometry, assuming d-wave pairing and anisotropic penetration depth, for realistic finite sample. Our novel, numerically implemented, perturbative procedure exploits the small ratio of the penetration depths to the sample size and substantially reduces the computational work required. We next generalize these considerations to other candidates for the energy gap and to perform node spectroscopy. In calculating the nonlinear supercurrent response, we include the effects of orthorhombic distortion and a-b plane anisotropy. Analytic results presented demonstrate a systematic way to experimentally distinguish order parameters of different symmetries, including cases with mixed symmetry (for example, d+s and s+id). We finally extend our findings to the case of low frequency harmonic magnetic field. The nonlinear magnetic response for various physical quantities generates higher harmonics of the frequency of the applied field. We discuss how examination of the field and angular dependences of these harmonics allows determination of the structure of the energy gap. We show how to distinguish nodes from small minima ("quasinodes"). Gaps with nodal lines give rise to universal power law field dependences for the nonlinear magnetic moment and torque. They both have separable temporal
Electrodynamic Dust Shield for Space Applications
NASA Technical Reports Server (NTRS)
Mackey, Paul J.; Johansen, Michael R.; Olsen, Robert C.; Raines, Matthew G.; Phillips, James R., III; Cox, Rachel E.; Hogue, Michael D.; Calle, Carlos I.; Pollard, Jacob R. S.
2016-01-01
The International Space Exploration Coordination Group (ISECG) has chosen dust mitigation technology as a Global Exploration Roadmap (GER) critical technology need in order to reduce life cycle cost and risk, and increase the probability of mission success. NASA has also included Particulate Contamination Prevention and Mitigation as a cross-cutting technology to be developed for contamination prevention, cleaning and protection. This technology has been highlighted due to the detrimental effect of dust on both human and robotic missions. During manned Apollo missions, dust caused issues with both equipment and crew. Contamination of equipment caused many issues including incorrect instrument readings and increased temperatures due to masking of thermal radiators. The astronauts were directly affected by dust that covered space suits, obscured face shields and later propagated to the cabin and into the crew's eyes and lungs. Robotic missions on Mars were affected when solar panels were obscured by dust thereby reducing the effectiveness of the solar panels. The Electrostatics and Surface Physics Lab in Swamp Works at the Kennedy Space Center has been developing an Electrodynamic Dust Shield (EDS) to remove dust from multiple surfaces, including glass shields and thermal radiators. This technology has been tested in lab environments and has evolved over several years. Tests of the technology include reduced gravity flights (6g) in which Apollo Lunar dust samples were successfully removed from glass shields while under vacuum (1 millipascal). Further development of the technology is underway to reduce the size of the EDS as well as to perform material and component testing outside of the International Space Station (ISS) on the Materials on International Space Station Experiment X (MISSE-X). This experiment is designed to verify that the EDS can withstand the harsh environment of space and will look to closely replicate the solar environment experienced on the moon
NASA Technical Reports Server (NTRS)
Khazanov, G. V.; Krivorutsky, E. N.; Gallagher, D. L.
2006-01-01
The concept of electrodynamic tether propulsion has a number of attractive features and has been widely discussed for different applications. Different system designs have been proposed and compared during the last 10 years. In spite of this, the choice of proper design for any particular mission is a unique problem. Such characteristics of tether performance as system acceleration, efficiency, etc., should be calculated and compared on the basis of the known capability of a tether to collect electrical current. We discuss the choice of parameters for circular and tape tethers with regard to the Momentum-Exchange/Electrodynamic Reboost (MXER) tether project.
Can the master time asymmetry in nature be electrodynamic in origin?
NASA Technical Reports Server (NTRS)
Leiter, D.
1985-01-01
If the electrodynamic measurement process is operationally described by imposing measurement color onto classical electrodynamics, self-energy infinities are eliminated and a retarded electrodynamic time arrow emerges dynamically from internal dynamic-stability conditions. This occurs because the new formalism contains nonlocal radiation fields which carry a negative parity under mathematical time reversal. This result is shown to be compatible with an extended form of T and CPT symmetry which preserves the dynamically chosen retarded electrodynamic arrow of time in the measurement color electrodynamic formalism.
On some electrodynamic properties of binary pulsars
NASA Astrophysics Data System (ADS)
Sironi, Lorenzo
2006-07-01
The main purpose of my thesis is to examine some electrodynamic properties of binary pulsars, trying to understand the peculiar physical processes that can happen in their magnetospheres; the ultimate aim is to discuss if such systems can be the source of the observed flux of cosmic rays between the knee and the ankle, since the mechanisms of acceleration for the cosmic rays in this range of energies are still unknown. Attention around binary pulsars has arisen after the recent discovery (December 2003) of the first double neutron star system in which both the stars are visible as pulsars (PSR J0737-3039); the inspection of the physical features of this binary pulsar has led to some intriguing possibilities up to now unexplored. In this thesis I will first of all review what is already known about the main properties of this binary system. I will describe in particular the possibility to go further in the verification of the predictions of general relativity with the so-called post-Keplerian parameters; I will discuss the possibility of studying the optical properties of the magnetospheres, since the inclination angle of the orbit is nearly 90Â° and some orbital phases show an eclipse of the light from one pulsar due to absorption by the magnetosphere of the companion; I will rapidly summarize how the discovery of that binary pulsar can enlarge our knowledge about the origin and evolution of double neutron star systems; lastly, I will examine the increase in the estimate of the Galactic double neutron star merger rate due to the discovery of PSR J0737-3039. I will then summarize the current knowledge about the magnetosphere of a single pulsar. After describing the Gold-Pacini model for the energy loss of the oblique rotator (in which the magnetic and rotational axes are not parallel), I will discuss the Goldreich-Julian model for the aligned axisymmetric rotator in the force-free approximation in which the inertial and gravitational forces are neglected with
The AMT maglev test sled -- EML weapons technology transition to transportation
Schaaf, J.C. Jr.; Zowarka, R.C. Jr.; Davey, K.; Weldon, J.M.
1997-01-01
Technology spinoffs from prior electromagnetic launcher work enhance a magnetic levitation transportation system test bed being developed by American Maglev Technology of Florida. This project uses a series wound linear DC motor and brushes to simplify the magnetic levitation propulsion system. It takes advantage of previous related work in electromagnetic launcher technology to achieve success with this innovative design. Technology and knowledge gained from developments for homopolar generators and proposed railgun arc control are key to successful performance. This contribution supports a cost effective design that is competitive with alternative concepts. Brushes transfer power from the guideway (rail) to the vehicle (armature) in a novel design that activates the guideway only under the vehicle, reducing power losses and guideway construction costs. The vehicle carries no power for propulsion and levitation, and acts only as a conduit for the power through the high speed brushes. Brush selection and performance is based on previous EML homopolar generator research. A counterpulse circuit, first introduced in an early EML conference, is used to suppress arcing on the trailing brush and to transfer inductive energy to the next propulsion coil. Isolated static lift and preliminary propulsion tests have been completed, and integrated propulsion and lift tests are scheduled in early 1996.
Manufacturing of a REBCO racetrack coil using thermoplastic resin aiming at Maglev application
NASA Astrophysics Data System (ADS)
Mizuno, Katsutoshi; Ogata, Masafumi; Hasegawa, Hitoshi
2015-11-01
The REBCO coated conductor is a promising technology for the Maglev application in terms of its high critical temperature. The operating temperature of the on-board magnets can be around 40-50 K with the coated conductor. The REBCO coils are cooled by cryocoolers directly, and hence the thermal design of the REBCO coils significantly changes from that of LTS coils. We have developed a novel REBCO coil structure using thermoplastic resin. The coil is not impregnated and the thermoplastic resin is used to bond the coil winding and the heat transfer members, e.g. copper and aluminum plates. The viscosity of the thermoplastic resin is high enough for the thermoplastic resin not to permeate between the turns in the coil. Therefore, the thermal stress does not occur and the risk of degradation is removed. This paper contains the following three topics. First, the thermal resistance of the thermoplastic resin was measured at cryogenic temperature. Then, a small round REBCO coil was experimentally produced. It has been confirmed that the thermoplastic resin does not cause the degradation and, the adhesion between the coil winding and copper plates withstands the thermal stress. Finally, we successfully produced a full-scale racetrack REBCO coil applying the coil structure with the thermoplastic resin.
A high precision position sensor design and its signal processing algorithm for a maglev train.
Xue, Song; Long, Zhiqiang; He, Ning; Chang, Wensen
2012-01-01
High precision positioning technology for a kind of high speed maglev train with an electromagnetic suspension (EMS) system is studied. At first, the basic structure and functions of the position sensor are introduced and some key techniques to enhance the positioning precision are designed. Then, in order to further improve the positioning signal quality and the fault-tolerant ability of the sensor, a new kind of discrete-time tracking differentiator (TD) is proposed based on nonlinear optimal control theory. This new TD has good filtering and differentiating performances and a small calculation load. It is suitable for real-time signal processing. The stability, convergence property and frequency characteristics of the TD are studied and analyzed thoroughly. The delay constant of the TD is figured out and an effective time delay compensation algorithm is proposed. Based on the TD technology, a filtering process is introduced in to improve the positioning signal waveform when the sensor is under bad working conditions, and a two-sensor switching algorithm is designed to eliminate the positioning errors caused by the joint gaps of the long stator. The effectiveness and stability of the sensor and its signal processing algorithms are proved by the experiments on a test train during a long-term test run.
A High Precision Position Sensor Design and Its Signal Processing Algorithm for a Maglev Train
Xue, Song; Long, Zhiqiang; He, Ning; Chang, Wensen
2012-01-01
High precision positioning technology for a kind of high speed maglev train with an electromagnetic suspension (EMS) system is studied. At first, the basic structure and functions of the position sensor are introduced and some key techniques to enhance the positioning precision are designed. Then, in order to further improve the positioning signal quality and the fault-tolerant ability of the sensor, a new kind of discrete-time tracking differentiator (TD) is proposed based on nonlinear optimal control theory. This new TD has good filtering and differentiating performances and a small calculation load. It is suitable for real-time signal processing. The stability, convergence property and frequency characteristics of the TD are studied and analyzed thoroughly. The delay constant of the TD is figured out and an effective time delay compensation algorithm is proposed. Based on the TD technology, a filtering process is introduced in to improve the positioning signal waveform when the sensor is under bad working conditions, and a two-sensor switching algorithm is designed to eliminate the positioning errors caused by the joint gaps of the long stator. The effectiveness and stability of the sensor and its signal processing algorithms are proved by the experiments on a test train during a long-term test run. PMID:22778582
Computational design and in vitro characterization of an integrated maglev pump-oxygenator.
Zhang, Juntao; Taskin, M Ertan; Koert, Andrew; Zhang, Tao; Gellman, Barry; Dasse, Kurt A; Gilbert, Richard J; Griffith, Bartley P; Wu, Zhongjun J
2009-10-01
For the need for respiratory support for patients with acute or chronic lung diseases to be addressed, a novel integrated maglev pump-oxygenator (IMPO) is being developed as a respiratory assist device. IMPO was conceptualized to combine a magnetically levitated pump/rotor with uniquely configured hollow fiber membranes to create an assembly-free, ultracompact system. IMPO is a self-contained blood pump and oxygenator assembly to enable rapid deployment for patients requiring respiratory support or circulatory support. In this study, computational fluid dynamics (CFD) and computer-aided design were conducted to design and optimize the hemodynamics, gas transfer, and hemocompatibility performances of this novel device. In parallel, in vitro experiments including hydrodynamic, gas transfer, and hemolysis measurements were conducted to evaluate the performance of IMPO. Computational results from CFD analysis were compared with experimental data collected from in vitro evaluation of the IMPO. The CFD simulation demonstrated a well-behaved and streamlined flow field in the main components of this device. The results of hydrodynamic performance, oxygen transfer, and hemolysis predicted by computational simulation, along with the in vitro experimental data, indicate that this pump-lung device can provide the total respiratory need of an adult with lung failure, with a low hemolysis rate at the targeted operating condition. These detailed CFD designs and analyses can provide valuable guidance for further optimization of this IMPO for long-term use.
A Toy Model of Electrodynamics in (1 + 1) Dimensions
ERIC Educational Resources Information Center
Boozer, A. D.
2007-01-01
A model is presented that describes a scalar field interacting with a point particle in (1+1) dimensions. The model exhibits many of the same phenomena that appear in classical electrodynamics, such as radiation and radiation damping, yet has a much simpler mathematical structure. By studying these phenomena in a highly simplified model, the…
The Two-Body Problem of Classical Electrodynamics
1980-06-01
and 7., are continuous positive functions of bounded variation . tApplied Mathematics Department 5640, Sandia National Laboratories, Albuquerque, NM...gi is a continuous function of bounded variation . This generalized Lipschitz-type condition is indeed satisfied in the electrodynamics case. The m
On the electrodynamics of Minkowski at low velocities
NASA Astrophysics Data System (ADS)
Rousseaux, G.
2008-10-01
The Galilean constitutive equations for the electrodynamics of moving media are derived for the first time. They explain all the historic and modern experiments which were interpreted so far in a relativistic framework assuming the constant light celerity principle. Here, we show the latter to be sufficient but not necessary.
Zero-point fluctuations in direct-action electrodynamics
NASA Astrophysics Data System (ADS)
Pegg, D. T.
1980-03-01
In quantized direct interparticle Wheeler-Feynman electrodynamics, no free-field bosonic commutation relations exist. It is shown that a test atom will nevertheless detect a zero-point fluctuating “field” whose source is the atoms of the absorber.
Scaling limit of quantum electrodynamics with spatial cutoffs
Takaesu, Toshimitsu
2011-02-15
In this paper, the Hamiltonian of quantum electrodynamics with spatial cutoffs is investigated. A scaled total Hamiltonian is introduced and its asymptotic behavior is investigated. In the main theorem, it is shown that the scaled total Hamiltonian converges to a self-adjoint operator in the strong resolvent sense, and the effective potential of the Dirac field is derived.
A Toy Model of Quantum Electrodynamics in (1 + 1) Dimensions
ERIC Educational Resources Information Center
Boozer, A. D.
2008-01-01
We present a toy model of quantum electrodynamics (QED) in (1 + 1) dimensions. The QED model is much simpler than QED in (3 + 1) dimensions but exhibits many of the same physical phenomena, and serves as a pedagogical introduction to both QED and quantum field theory in general. We show how the QED model can be derived by quantizing a toy model of…
Application of Science Aesthetics in the Teaching of Electrodynamics
ERIC Educational Resources Information Center
Li, Haiyan
2010-01-01
As the important part of the theoretical physics, the electrodynamics is a theoretical basic course of the physics and relative subjects. To adapt the demands for cultivating the target of highly-quality talents in the 21st century, the aesthetic principle can be used in the teaching to stimulate students' learning desire and cultivate students'…
Nanoscale Thermal Transfer - An Invitation to Fluctuation Electrodynamics
NASA Astrophysics Data System (ADS)
Henkel, Carsten
2017-02-01
An electromagnetic theory of thermal radiation is outlined, based on the fluctuation electrodynamics of Rytov and co-workers. We discuss the basic concepts and the status of different approximations. The physical content is illustrated with a few examples on near-field heat transfer.
Electrodynamics, Differential Forms and the Method of Images
ERIC Educational Resources Information Center
Low, Robert J.
2011-01-01
This paper gives a brief description of how Maxwell's equations are expressed in the language of differential forms and use this to provide an elegant demonstration of how the method of images (well known in electrostatics) also works for electrodynamics in the presence of an infinite plane conducting boundary. The paper should be accessible to an…
Electrodynamic Tether Propulsion for Spacecraft and Upper Stages
NASA Technical Reports Server (NTRS)
Johnson, Les; Gilchrist, Brian; Estes, Robert D.; Lorenzini, Rnrico; Martinez-Sanchez, Manuel; Sanmartin, Juan
1998-01-01
Relatively short electrodynamic tethers can use solar power to 'push' against a planetary magnetic field to achieve propulsion without the expenditure of propellant. The groundwork has been laid for this type of propulsion. Important recent milestones include retrieval of a tether in space (TSS-1, 1992), successful deployment of a 20-km-long tether in space (SEDS-1, 1993), and operation of an electrodynamic tether with tether current driven in both directions (PMG, 1993). The planned Propulsive Small Expendable Deployer System (ProSEDS) experiment will use the flight-proven Small Expendable Deployer System (SEDS) to deploy a 5 km bare copper tether from a Delta II upper stage to achieve approximately 0.4 N drag thrust, thus deorbiting the stage. The experiment will use a predominantly 'bare' tether for current collection in lieu of the endmass collector and insulated tether approach used on previous missions. The flight experiment is a precursor to utilization of the technology on the International Space Station for reboost and the electrodynamic tether upper stage demonstration mission which will be capable of orbit raising, lowering and inclination changes, all using electrodynamic thrust. In addition, the use of this type of propulsion may be attractive for future missions at Jupiter.
Linear stochastic electrodynamics: Looking for the physics behind quantum theory
NASA Astrophysics Data System (ADS)
de la Peña, Luis; Cetto, Ana María
1999-03-01
In this chapter, which covers part of the course given at ELAF, a straight-forward procedure is presented that leads from the basic postulates of stochastic electrodynamics to the usual formalism of quantum theory. The theory thus developed is called linear stochastic electrodynamics, to underline that one of its basic features is the (asymptotic) linear response of atomic systems to the background field. The chapter starts with a brief discussion of some open questions in quantum theory and of the possibility to find an answer to them by resorting to the zeropoint radiation field as the source of the quantum behavior of matter. The basic properties of this field are discussed, and a brief enumeration is made of some of the positive results and vital shortcomings of standard stochastic electrodynamics. After identifying the source of these shortcomings in the assumption that the background field is not altered by its interaction with matter, linear stochastic electrodynamics is developed and shown to lead, under certain approximations, to a consistent picture of both matter and field quantization. In the concluding part, it is shown that also the electron spin can be considered to be generated by the interaction of the particle with the zeropoint field; in particular, the two-valuedness of the spin projection is associated with the existence of just two independent states of polarization of the field.
Quantum mechanical ground state of hydrogen obtained from classical electrodynamics
NASA Astrophysics Data System (ADS)
Cole, Daniel C.; Zou, Yi
2003-10-01
The behavior of a classical charged point particle under the influence of only a Coulombic binding potential and classical electromagnetic zero-point radiation, is shown to agree closely with the probability density distribution of Schrödinger's wave equation for the ground state of hydrogen. These results again raise the possibility that the main tenets of stochastic electrodynamics (SED) are correct.
Apparent Paradoxes in Classical Electrodynamics: Relativistic Transformation of Force
ERIC Educational Resources Information Center
Kholmetskii, A. L.; Yarman, T.
2007-01-01
In this paper, we analyse a number of paradoxical teaching problems of classical electrodynamics, dealing with the relativistic transformation of force for complex macro systems, consisting of a number of subsystems with nonzero relative velocities such as electric circuits that change their shape in the course of time. (Contains 7 figures.)
Rapidly rotating pulsar radiation in vacuum nonlinear electrodynamics
NASA Astrophysics Data System (ADS)
Denisov, V. I.; Denisova, I. P.; Pimenov, A. B.; Sokolov, V. A.
2016-11-01
In this paper we investigate the corrections of vacuum nonlinear electrodynamics on rapidly rotating pulsar radiation and spin-down in the perturbative QED approach (post-Maxwellian approximation). An analytical expression for the pulsar's radiation intensity has been obtained and analyzed.
Large- and Small-Scale Ring Current Electrodynamic Coupling
NASA Technical Reports Server (NTRS)
Khazanov, G. V.
2003-01-01
In this talk we will address the two primary issues of ring current (RC) electrodynamic coupling: 1. RC self-consistent magnetosphere-ionosphere coupling that includes calculation of the magnetospheric electric field (large scale electrodynamic coupling); and 2. RC self-consistent coupling with electromagnetic ion cyclotron (EMIC) waves (small scale electrodynamic coupling). Our study will be based on two RC models that we have recently developed in our group. The first model by Khazanov et al. [2002] couples the system of two kinetic equations: one equation which describes the RC ion dynamics and another equation which describes the energy density evolution of EMIC waves. The second model by Khazanov et al. [2003] deals with large scale electrodynamic coupling processes and provides a self-consistent simulation of RC ions and the magnetospheric electric field. There is presently no model that addresses both of these issues simultaneously in a self-consistent calculation. However, the need exists for such a model, because these two processes directly influence each other, with the mesoscale coupling changing the drift paths of the thermal and energetic particle populations in the inner magnetosphere, thereby changing the wave interactions, and the microscale coupling altering the pitch angle distributions and ionospheric conductivities (through increased precipitation), thus changing the field-aligned currents and electric potential structure. The initial thrust of the work will be the development of a combined kinetic model of micro- and meso-scale RC electrodynamic coupling processes and to examine their interactions with each other on a global scale.
Maglev Launch: Ultra-low Cost, Ultra-high Volume Access to Space for Cargo and Humans
NASA Astrophysics Data System (ADS)
Powell, James; Maise, George; Rather, John
2010-01-01
Despite decades of efforts to reduce rocket launch costs, improvements are marginal. Launch cost to LEO for cargo is ~$10,000 per kg of payload, and to higher orbit and beyond much greater. Human access to the ISS costs $20 million for a single passenger. Unless launch costs are greatly reduced, large scale commercial use and human exploration of the solar system will not occur. A new approach for ultra low cost access to space-Maglev Launch-magnetically accelerates levitated spacecraft to orbital speeds, 8 km/sec or more, in evacuated tunnels on the surface, using Maglev technology like that operating in Japan for high speed passenger transport. The cost of electric energy to reach orbital speed is less than $1 per kilogram of payload. Two Maglev launch systems are described, the Gen-1System for unmanned cargo craft to orbit and Gen-2, for large-scale access of human to space. Magnetically levitated and propelled Gen-1 cargo craft accelerate in a 100 kilometer long evacuated tunnel, entering the atmosphere at the tunnel exit, which is located in high altitude terrain (~5000 meters) through an electrically powered ``MHD Window'' that prevents outside air from flowing into the tunnel. The Gen-1 cargo craft then coasts upwards to space where a small rocket burn, ~0.5 km/sec establishes, the final orbit. The Gen-1 reference design launches a 40 ton, 2 meter diameter spacecraft with 35 tons of payload. At 12 launches per day, a single Gen-1 facility could launch 150,000 tons annually. Using present costs for tunneling, superconductors, cryogenic equipment, materials, etc., the projected construction cost for the Gen-1 facility is 20 billion dollars. Amortization cost, plus Spacecraft and O&M costs, total $43 per kg of payload. For polar orbit launches, sites exist in Alaska, Russia, and China. For equatorial orbit launches, sites exist in the Andes and Africa. With funding, the Gen-1 system could operate by 2020 AD. The Gen-2 system requires more advanced technology
NASA Astrophysics Data System (ADS)
Yang, Peng-Tao; Yang, Wan-Min; Wang, Miao; Li, Jia-Wei; Guo, Yu-Xia
2015-11-01
The influence of the width of the middle magnet in the permanent magnet guideways (PMGs) on the levitation force and the levitation height of single-domain yttrium barium copper oxide (YBCO) bulks has been investigated at 77 K under the zero field cooled (ZFC) state. It is found that the largest levitation force can be obtained in the system with the width of the middle magnet of the PMG equal to the size of the YBCO bulk when the gap between the YBCO bulk and PMG is small. Both larger levitation force and higher levitation height can be obtained in the system with the width of the middle magnet of the PMG larger than the size of the YBCO bulk. The stiffness of the levitation force between the PMG and the YBCO bulk is higher in the system with a smaller width of the middle magnet in the PMG. These results provide an effective way to control the levitation force and the levitation height for the superconducting maglev design and applications. Project supported by the National Natural Science Foundation of China (Grant Nos. 51342001 and 50872079), the Key-grant Project of Chinese Ministry of Education (Grant No. 311033), the Research Fund for the Doctoral Program of Higher Education of China (Grant No. 20120202110003), the Innovation Team in Shaanxi Province, China (Grant No. 2014KTC-18), and the Fundamental Research Funds for the Central Universities, China (Grant Nos. GK201101001 and GK201305014), and the Outstanding Doctoral Thesis Foundation Project of Shaanxi Normal University, China (Grant Nos. X2011YB08 and X2012YB05).
NASA Astrophysics Data System (ADS)
Mizuno, Katsutoshi; Ogata, Masafumi; Hasegawa, Hitoshi
2014-11-01
The REBCO coated conductor has been attracted attention because of its high current density in the presence of high magnetic field. If the coated conductor is applied to Maglev, the operational temperature of the on-board magnets will be over 40 K and energy consumption of cryocoolers will be reduced. That high operational temperature also means the absence of liquid helium. Therefore, reliable thermal coupling is desirable for cooling the coils. We propose an epoxy impregnated REBCO coil co-wound with PTFE tape. While the PTFE tape prevents the performance degradation of the coil, the epoxy resin bonds the coil to cooling members. We carried out three experiments to confirm that the coil structure which we propose has robust thermal coupling without the degradation. First, thermal resistances of paraffin and epoxy were measured varying the temperature from room temperature to 10 K. The measurement result indicates that paraffin has a risk of losing thermal coupling during cooling down. In another experiment, PTFE (polytetrafluoroethylene) tape insulator prevented performance degradation of a small epoxy impregnated REBCO coil, while another REBCO coil with polyimide tape showed clear performance degradation. Finally, we produced a racetrack REBCO coil with the same outer dimension as a Maglev on-board magnet coil. Although the racetrack coil was installed in a GFRP coil case and tightly bonded to the case by epoxy impregnation, any performance degradation was not observed.
NASA Astrophysics Data System (ADS)
Wang, B.; Zheng, J.; Che, T.; Zheng, B. T.; Si, S. S.; Deng, Z. G.
2015-12-01
The permanent magnet guideway (PMG) is very important for the performance of the high temperature superconducting (HTS) system in terms of electromagnetic force and operational stability. The dynamic response characteristics of a HTS maglev model levitating on two types of PMG, which are the normal PMG with iron flux concentration and Halbach-type PMG, were investigated by experiments. The dynamic signals for different field-cooling heights (FCHs) and loading/unloading processes were acquired and analyzed by a vibration analyzer and laser displacement sensors. The resonant frequency, stiffness and levitation height of the model were discussed. It was found that the maglev model on the Halbach-type PMG has higher resonant frequency and higher vertical stiffness compared with the normal PMG. However, the low lateral stiffness of the model on the Halbach-type PMG indicates poor lateral stability. Besides, the Halbach-type PMG has better loading capacity than the normal PMG. These results are helpful to design a suitable PMG for the HTS system in practical applications.
Vyas, A.D.; Pitstick, M.E.; Rote, D.M.; Johnson, L.R.; Bernard, M.J. III
1994-01-01
High-speed rail (HSR) and magnetically levitated (maglev) vehicles will provide an alternative mode of transportation for intercity travel, particularly for short and medium-length trips between 100 and 600 miles (160 to 960 kilometers). A significant portion of highway and air travel can potentially be diverted to such high-speed ground transportation (HSGT) systems. Also, electric utilities will have to meet the energy demands of these systems. Because these systems require significant investments and time to construct an extensive network, they need more time for analysis and planning. This study evaluates the patterns of growth for these systems and the factors affecting that growth for the year 2010 to determine the magnitude of intercity travel, the basis for HSGT use and electricity demand. To forecast the number and frequency of intercity trips, a methodology was developed that accounts for the travelers` socioeconomic status and the attractiveness of metropolitan areas. The study revealed that aggregate travel demand relied upon population growth, the employment status of the traveler, their household size, and income. Further, the study projects travel for 78 major metropolitan areas via air and highway, and identifies the 12 highest density corridors, describing the potential for HSGT systems to substitute some of that travel. In addition, the study estimates the energy demand and power requirements for a representative high-speed rail and maglev system for each corridor and the corridor connections.
Electrodynamic Tether Propulsion and Power Generation at Jupiter
NASA Technical Reports Server (NTRS)
Gallagher, D. L.; Johnson, L.; Moore, J.; Bagenal, F.
1998-01-01
The results of a study performed to evaluate the feasibility and merits of using an electrodynamic tether for propulsion and power generation for a spacecraft in the Jovian system are presented. The environment of the Jovian system has properties which are particularly favorable for utilization of an electrodynamic tether. Specifically, the planet has a strong magnetic field and the mass of the planet dictates high orbital velocities which, when combined with the planet's rapid rotation rate, can produce very large relative velocities between the magnetic field and the spacecraft. In a circular orbit close to the planet, tether propulsive forces are found to be as high as 50 N and power levels as high as 1 MW.
Structures of general relativity in dilaton-Maxwell electrodynamics
NASA Astrophysics Data System (ADS)
Kechkin, O. V.; Mosharev, P. A.
2016-08-01
It is shown that electro (magneto) static sector of Maxwell’s electrodynamics coupled to the dilaton field in a string theory form possesses the symmetry group of the stationary General Relativity in vacuum. Performing the Ernst formalism, we develope a technique for generation of exact solutions in this modified electrodynamics on the base of the normalized Ehlers symmetry transformation. In the electrostatic case, we construct and study a general class of spherically symmetric solutions that describes a pointlike source of the Coulomb type. It is demonstrated that this source is characterized by finite and singularity-free interaction at short distances. Also it is established that the total electrostatic energy of this source is finite and inversely proportional to the dilaton-Maxwell coupling constant.
Cosmology and action-at-a-distance electrodynamics
NASA Astrophysics Data System (ADS)
Hoyle, F.; Narlikar, J. V.
1995-01-01
This article reviews the developments in the electrodynamics of direct interparticle action, emphasizing the achievements in quantum as well as classical electrodynamics. It is shown that the application of the Wheeler-Feynman absorber theory of radiation places stringent requirements on the asymptotic future and past light cones of the universe. All Friedmann cosmologies fail to meet these requirements, but the steady-state and the quasi-steady-state models have the right kind of structure to make the theory work. Further, it is shown that the working theory is free from the problems of divergence that trouble the classical and quantum field theory. In particular, no renormalization is needed: The bare mass and bare charge of an electron are finite. A few ideas relating to the response of the universe to a local microscopic experiment are presented as well as on possible clues to the outstanding issues of foundations of quantum theory.
Towards hybrid circuit quantum electrodynamics with quantum dots
NASA Astrophysics Data System (ADS)
Viennot, Jérémie J.; Delbecq, Matthieu R.; Bruhat, Laure E.; Dartiailh, Matthieu C.; Desjardins, Matthieu M.; Baillergeau, Matthieu; Cottet, Audrey; Kontos, Takis
2016-08-01
Cavity quantum electrodynamics allows one to study the interaction between light and matter at the most elementary level. The methods developed in this field have taught us how to probe and manipulate individual quantum systems like atoms and superconducting quantum bits with an exquisite accuracy. There is now a strong effort to extend further these methods to other quantum systems, and in particular hybrid quantum dot circuits. This could turn out to be instrumental for a noninvasive study of quantum dot circuits and a realization of scalable spin quantum bit architectures. It could also provide an interesting platform for quantum simulation of simple fermion-boson condensed matter systems. In this short review, we discuss the experimental state of the art for hybrid circuit quantum electrodynamics with quantum dots, and we present a simple theoretical modeling of experiments.
Atomic electron energies including relativistic effects and quantum electrodynamic corrections
NASA Technical Reports Server (NTRS)
Aoyagi, M.; Chen, M. H.; Crasemann, B.; Huang, K. N.; Mark, H.
1977-01-01
Atomic electron energies have been calculated relativistically. Hartree-Fock-Slater wave functions served as zeroth-order eigenfunctions to compute the expectation of the total Hamiltonian. A first order correction to the local approximation was thus included. Quantum-electrodynamic corrections were made. For all orbitals in all atoms with 2 less than or equal to Z less than or equal to 106, the following quantities are listed: total energies, electron kinetic energies, electron-nucleus potential energies, electron-electron potential energies consisting of electrostatic and Breit interaction (magnetic and retardation) terms, and vacuum polarization energies. These results will serve for detailed comparison of calculations based on other approaches. The magnitude of quantum electrodynamic corrections is exhibited quantitatively for each state.
Dendrimer light-harvesting: intramolecular electrodynamics and mechanisms.
Andrews, David L; Bradshaw, David S; Jenkins, Robert D; Rodríguez, Justo
2009-12-07
In the development of highly efficient materials for harvesting solar energy, there is an increasing focus on purpose-built dendrimers and allied multi-chromophore systems. A proliferation of antenna chromophores is not the only factor determining the sought light-harvesting efficiency; the internal geometry and photophysics of these molecules are also crucially important. In particular, the mechanisms by means of which radiant energy is ultimately trapped depends on an intricate interplay of electronic, structural, energetic and symmetry properties. To better understand these processes a sound theoretical representation of the intramolecular electrodynamics is required. A suitable formalism, based on quantum electrodynamics, readily delivers physical insights into the necessary excitation channelling processes, and it affords a rigorous basis for modelling the intramolecular flow of energy.
The electric field and global electrodynamics of the magnetosphere
NASA Technical Reports Server (NTRS)
Stern, D. P.
1979-01-01
The conception of the electrodynamics of the quiet-time magnetosphere obtained during the last four years of magnetospheric study is presented. Current understandings of the open magnetosphere, convective plasma flows in the plasma sheet, the shielding of the inner magnetosphere from the convective magnetospheric electric field, the space charge produced when injected electrons drift towards dawn and injected ions drift towards dusk, the disruption of the flow of the Birkeland current by plasma instabilities and the shielding of the convective electric field by the dayside magnetopause are discussed. Attention is also given to changes of magnetic field line topology magnetic storms and substorms. Unresolved questions and new tools which may play a role in the further understanding of magnetospheric electrodynamics and the role of the magnetospheric electric field are presented.
Evidence for nonlocal electrodynamics in planar Josephson junctions.
Boris, A A; Rydh, A; Golod, T; Motzkau, H; Klushin, A M; Krasnov, V M
2013-09-13
We study the temperature dependence of the critical current modulation I(c)(H) for two types of planar Josephson junctions: a low-Tc Nb/CuNi/Nb and a high-Tc YBa2Cu3O(7-δ) bicrystal grain-boundary junction. At low T both junctions exhibit a conventional behavior, described by the local sine-Gordon equation. However, at elevated T the behavior becomes qualitatively different: the I(c)(H) modulation field ΔH becomes almost T independent and neither ΔH nor the critical field for the penetration of Josephson vortices vanish at Tc. Such an unusual behavior is in good agreement with theoretical predictions for junctions with nonlocal electrodynamics. We extract absolute values of the London penetration depth λ from our data and show that a crossover from local to nonlocal electrodynamics occurs with increasing T when λ(T) becomes larger than the electrode thickness.
Quantum electrodynamics near a photonic band-gap
NASA Astrophysics Data System (ADS)
Liu, Yanbing; Houck, Andrew
Quantum electrodynamics predicts the localization of light around an atom in photonic band-gap (PBG) medium or photonic crystal. Here we report the first experimental realization of the strong coupling between a single artificial atom and an one dimensional PBG medium using superconducting circuits. In the photonic transport measurement, we observe an anomalous Lamb shift and a large band-edge avoided crossing when the artificial atom frequency is tuned across the band-edge. The persistent peak within the band-gap indicates the single photon bound state. Furthermore, we study the resonance fluorescence of this bound state, again demonstrating the breakdown of the Born-Markov approximation near the band-edge. This novel architecture can be directly generalized to study many-body quantum electrodynamics and to construct more complicated spin chain models.
On the electrodynamics of Josephson effect in anisotropic superconductors
Mints, R.G.
1989-01-01
Specificities of Josephson effect electrodynamics in anisotropic superconductors are of considerable interest for the study of high temperature superconductors with strongly anisotropic layered structure. In this paper the authors give the calculation for the tunnel Josephson contact of an isolated vortex, the law of dispersion of its low-amplitude oscillations, the critical field H/sub cl/ for the penetration of magnetic flux, and the maximum current across a rectangular contact.
Clothed Particles in Quantum Electrodynamics and Quantum Chromodynamics
NASA Astrophysics Data System (ADS)
Shebeko, Alexander
2016-03-01
The notion of clothing in quantum field theory (QFT), put forward by Greenberg and Schweber and developed by M. Shirokov, is applied in quantum electrodynamics (QED) and quantum chromodynamics (QCD). Along the guideline we have derived a novel analytic expression for the QED Hamiltonian in the clothed particle representation (CPR). In addition, we are trying to realize this notion in QCD (to be definite for the gauge group SU(3)) when drawing parallels between QCD and QED.
Non-US electrodynamic launchers research and development
Parker, J.V.; Batteh, J.H.; Greig, J.R.; Keefer, D.; McNab, I.R.; Zabar, Z.
1994-11-01
Electrodynamic launcher research and development work of scientists outside the United States is analyzed and assessed by six internationally recognized US experts in the field of electromagnetic and electrothermal launchers. The assessment covers five broad technology areas: (1) Experimental railguns; (2) Railgun theory and design; (3) Induction launchers; (4) Electrothermal guns; (5) Energy storage and power supplies. The overall conclusion is that non-US work on electrodynamic launchers is maturing rapidly after a relatively late start in many countries. No foreign program challenges the US efforts in scope, but it is evident that the United States may be surpassed in some technologies within the next few years. Until recently, published Russian work focused on hypervelocity for research purposes. Within the last two years, large facilities have been described where military-oriented development has been underway since the mid-1980s. Financial support for these large facilities appears to have collapsed, leaving no effective effort to develop practical launchers for military or civilian applications. Electrodynamic launcher research in Europe is making rapid progress by focusing on a single application, tactical launchers for the military. Four major laboratories, in Britain, France, Germany, and the Netherlands, are working on this problem. Though narrower in scope than the US effort, the European work enjoys a continuity of support that has accelerated its progress. The next decade will see the deployment of electrodynamic launcher technology, probably in the form of an electrothermal-chemical upgrade for an existing gun system. The time scale for deployment of electromagnetic launchers is entirely dependent on the level of research-and-development effort. If resources remain limited, the advantage will lie with cooperative efforts that have reasonably stable funding such as the present French-German program.
Emergent electrodynamics of skyrmions in a chiral magnet
NASA Astrophysics Data System (ADS)
Schulz, T.; Ritz, R.; Bauer, A.; Halder, M.; Wagner, M.; Franz, C.; Pfleiderer, C.; Everschor, K.; Garst, M.; Rosch, A.
2012-04-01
When an electron moves in a smoothly varying non-collinear magnetic structure, its spin orientation adapts constantly, thereby inducing forces that act both on the magnetic structure and on the electron. These forces may be described by electric and magnetic fields of an emergent electrodynamics. The topologically quantized winding number of so-called skyrmions--a type of magnetic whirl discovered recently in chiral magnets--has been predicted to induce exactly one quantum of emergent magnetic flux per skyrmion. A moving skyrmion is therefore expected to induce an emergent electric field following Faraday's law of induction, which inherits this topological quantization. Here we report Hall-effect measurements that establish quantitatively the predicted emergent electrodynamics. We obtain quantitative evidence for the depinning of skyrmions from impurities (at current densities of only 106Am-2) and their subsequent motion. The combination of exceptionally small current densities and simple transport measurements offers fundamental insights into the connection between the emergent and real electrodynamics of skyrmions in chiral magnets, and might, in the long term, be important for applications.
Radiation and matter: Electrodynamics postulates and Lorenz gauge
NASA Astrophysics Data System (ADS)
Bobrov, V. B.; Trigger, S. A.; van Heijst, G. J.; Schram, P. P.
2016-11-01
In general terms, we have considered matter as the system of charged particles and quantized electromagnetic field. For consistent description of the thermodynamic properties of matter, especially in an extreme state, the problem of quantization of the longitudinal and scalar potentials should be solved. In this connection, we pay attention that the traditional postulates of electrodynamics, which claim that only electric and magnetic fields are observable, is resolved by denial of the statement about validity of the Maxwell equations for microscopic fields. The Maxwell equations, as the generalization of experimental data, are valid only for averaged values. We show that microscopic electrodynamics may be based on postulation of the d'Alembert equations for four-vector of the electromagnetic field potential. The Lorenz gauge is valid for the averages potentials (and provides the implementation of the Maxwell equations for averages). The suggested concept overcomes difficulties under the electromagnetic field quantization procedure being in accordance with the results of quantum electrodynamics. As a result, longitudinal and scalar photons become real rather than virtual and may be observed in principle. The longitudinal and scalar photons provide not only the Coulomb interaction of charged particles, but also allow the electrical Aharonov-Bohm effect.
Electrodynamic Tethers for Reboost of the International Space Station
NASA Technical Reports Server (NTRS)
Johnson, Les; Herrmann, Melody; Vas, Irwin; Estes, Bob
1999-01-01
The International Space Station (ISS) will require periodic reboost due to atmospheric aerodynamic drag. This is nominally achieved through the use of thruster firings by the attached Progress M spacecraft. Many Progress flights to the ISS are required annually. Electrodynamic tethers provide an attractive alternative in that they can provide periodic reboost or continuous drag cancellation using no consumables, propellant nor conventional propulsion elements. The system could also serve as an emergency backup reboost system used only in the event resupply and reboost are delayed for some reason. The system also has direct application to spacecraft and upper stage propulsion. Electrodynamic tethers have been demonstrated in space previously with the Plasma Motor Generator (PMG) experiment and the Tethered Satellite System (TSS-IR). The advanced electrodynamic tether proposed for ISS reboost has significant advantages over previous systems in that hi-her thrust is achievable with significantly shorter tethers and without the need for an active current collection device, hence making the system simpler and much less expensive.
Large Scale High-Latitude Ionospheric Electrodynamic Fields and Currents
NASA Astrophysics Data System (ADS)
Lu, Gang
2017-03-01
This paper provides an overview as well as the application of the Assimilative Mapping of Ionospheric Electrodynamics (AMIE) procedure. AMIE synthesizes observations from various ground-based and space-born instruments to derive global patterns of ionospheric conductance, electric fields, ionospheric equivalent current, horizontal currents, field-aligned currents, and other related electrodynamic fields simultaneously. Examples are presented to illustrate the effects of the different data inputs on the AMIE outputs. The AMIE patterns derived from ground magnetometer data are generally similar to those derived from satellite magnetometer data. But ground magnetometer data yield a cross-polar potential drop that is about 15-45 % smaller than that derived from satellite magnetometer data. Ground magnetometers also grossly underestimate the magnetic perturbations in space when compared with the in situ satellite magnetometer data. However, when satellite magnetometer data are employed, AMIE is able to replicate the observed magnetic perturbations along the satellite tracks with a mean root-mean-square (RMS) error of 17-21 %. In addition to derive snapshots of ionospheric electrodynamic fields, the utility of AMIE can be easily expanded to obtain the average distributions of these fields along with their associated variability. Such information should be valuable to the analysis and interpretation of the Swarm observations.
ElectroDynamic Debris Eliminator (EDDE): Design, Operation, and Ground Support
2010-09-01
Research, Inc. Joseph Carroll Tether Applications, Inc. ABSTRACT The ElectroDynamic Debris Eliminator (EDDE) is a low -cost solution for LEO...rockets could be used in a single orbit inclination to attach drag devices such as balloons or passive electrodynamic tethers to drag the debris down...by AFRL. U.S. Government or Federal Rights License 14. ABSTRACT The ElectroDynamic Debris Eliminator (EDDE) is a low -cost solution for LEO space
NASA Astrophysics Data System (ADS)
Plimak, L. I.; Ivanov, Misha; Aiello, A.; Stenholm, S.
2015-08-01
Quantum electrodynamics under conditions of distinguishability of interacting matter entities, and of controlled actions and back-actions between them, is considered. Such "mesoscopic quantum electrodynamics" is shown to share its dynamical structure with the classical stochastic electrodynamics. In formal terms, we demonstrate that all general relations of the mesoscopic quantum electrodynamics may be recast in a form lacking Planck's constant. Mesoscopic quantum electrodynamics is therefore subject to "doing quantum electrodynamics while thinking classically," allowing one to substitute essentially classical considerations for quantum ones without any loss in generality. Implications of these results for the quantum measurement theory are discussed.
NASA Astrophysics Data System (ADS)
Wei, Qin; Yu, Fan; Jin, Fang; Shuo, Li; Guoguo, Li; Gang, Lv
2012-04-01
A new high temperature superconductor axial-flux coreless maglev motor (HTS AFIM) is proposed, of which the primary windings are made of HTS tapes and the secondary is a non-magnetic conductor. The main works of this paper are the magnetic-field computation and characteristics analysis of HTS AFIM. For the first one, the reduction of magnetic fields near outer and inner radius of the HTS AFIM is solved by introducing the sub-loop electro-magnetic model along the radial position. For the second one, the AC losses of HTS coils are calculated. The relationships between the device's characteristics and device parameters are presented, and the results indicate that under certain frequency and current levitation device can output enough lift force. The conclusions are verified by finite element calculations.
Evaluation of a six-DOF electrodynamic shaker system.
Gregory, Danny Lynn; Smallwood, David Ora
2009-03-01
The paper describes the preliminary evaluation of a 6 degree of freedom electrodynamic shaker system. The 8 by 8 inch (20.3 cm) table is driven by 12 electrodynamic shakers producing motion in all 6 rigid body modes. A small electrodynamic shaker system suitable for small component testing is described. The principal purpose of the system is to demonstrate the technology. The shaker is driven by 12 electrodynamic shakers each with a force capability of about 50 lbs (220 N). The system was developed through an informal cooperative agreement between Sandia National Laboratories, Team Corp. and Spectral Dynamics Corporation. Sandia provided the laboratory space and some development funds. Team provided the mechanical system, and Spectral Dynamics provided the control system. Spectral Dynamics was chosen to provide the control system partly because of their experience in MIMO control and partly because Sandia already had part of the system in house. The shaker system was conceived and manufactured by TEAM Corp. Figure 1 shows the overall system. The vibration table, electrodynamic shakers, hydraulic pumps, and amplifiers are all housed in a single cabinet. Figure 2 is a drawing showing how the electrodynamic shakers are coupled to the table. The shakers are coupled to the table through a hydraulic spherical pad bearing providing 5 degrees of freedom and one stiff degree of freedom. The pad bearing must be preloaded with a static force as they are unable to provide any tension forces. The horizontal bearings are preloaded with steel springs. The drawing shows a spring providing the vertical preload. This was changed in the final design. The vertical preload is provided by multiple strands of an O-ring material as shown in Figure 4. Four shakers provide excitation in each of the three orthogonal axes. The specifications of the shaker are outlined in Table 1. Four shakers provide inputs in each of the three orthogonal directions. By choosing the phase relationships
Electrodynamic Balance for Studies of Cosmic Dust Particles
NASA Technical Reports Server (NTRS)
Spann, J. F.; Abbas, M. M.; Venturini, C. C.; Comfort, R. H.; Rose, M. Franklin (Technical Monitor)
2000-01-01
Knowledge of the formation and distribution of interstellar, interplanetary, and planetary dust grains, and their physical, chemical and optical characteristics provide valuable information about many issues dealing with the origin and formation of the solar system bodies, interplanetary and interstellar environments as well as various industrial processes. Understanding the microphysics of individual grains and their interaction with the surrounding, environment is key to properly model various conditions and interpret existing data. The theory and models of individual dust grains are well developed for environments that vary from dense planetary atmospheres to dusty plasmas to diffuse environments such as interplanetary space. However, experimental investigations of individual dust grains in equilibrium are less common, perhaps due to the difficulty of these experiments. Laboratory measurements of dust grains have primarily measured ensemble properties or transient properties of single grains. A technique developed in the 1950's for ion spectroscopy, generally referred to as a quadrupole trap has recently been employed as an electrodynamic balance to investigate single micron-sized dust grains and for atmospheric aerosol research. A description of the theoretical basis and the experimental setup of the electrodynamic balance being developed in our laboratory are given. This laboratory technique lends itself to many applications that relate to planetary atmospheres, heliospheric environments, pre-stellar and pre-planetary conditions, and industrial settings. We present results from some recent experiments carried out to investigate the equilibrium potential of dust grains exposed to far ultraviolet light or to an electron beam. Some future experiments using an electrodynamic balance to investigate the optical characteristics, and condensation process involving dust grains in various astrophysical environments are discussed.
Spin pumping in electrodynamically coupled magnon-photon systems
NASA Astrophysics Data System (ADS)
Bai, Lihui
The electronics industry is quickly approaching the limitation of Moore's Law due to Joule heating in high density-integrated devices. To achieve new higher-speed devices and reduce energy consumption, researchers are turning to spintronics where the intrinsic spin, rather than the charge of electrons, is used to carry information in devices. Advances in spintronics have led to the discovery of giant magnetoresistance (GMR), spin transfer torque etc. Another subject, cavity electrodynamics, promises a completely new quantum algorithm by studying the properties of a single electron interacting with photons inside of a cavity. By merging both spintronics and cavity electrodynamics, a new cutting edge field called Cavity Spintronics is forming, which draws on the advantages of both subjects to develop new spintronics devices utilizing light-matter interaction. In this work, we use electrical detection, in combination with microwave transmission, to investigate both resonant and nonresonant magnon-photon coupling in a microwave cavity at room temperature. Spin pumping in a dynamically coupled magnon-photon system is found to be distinctly different from previous experiments. Characteristic coupling features such as modes anticrossing, linewidth evolution, peculiar line shape, and resonance broadening are systematically measured and consistently analyzed by a theoretical model set on the foundation of classical electrodynamic coupling. Our experimental and theoretical approach paves the way for pursuing microwave coherent manipulation of pure spin current via the combination of spin pumping and magnon-photon coupling. Co-authored with M. Harder, C.-M. Hu from University of Manitoba, Y. P. Chen, J. Q. Xiao from University of Delaware, and X. Fan from Univeristy of Denver.
NASA Technical Reports Server (NTRS)
Maynard, N. C. (Editor)
1979-01-01
Significant deficiencies exist in the present understanding of the basic physical processes taking place within the middle atmosphere (the region between the tropopause and the mesopause), and in the knowledge of the variability of many of the primary parameters that regulate Middle Atmosphere Electrodynamics (MAE). Knowledge of the electrical properties, i.e., electric fields, plasma characteristics, conductivity and currents, and the physical processes that govern them is of fundamental importance to the physics of the region. Middle atmosphere electrodynamics may play a critical role in the electrodynamical aspects of solar-terrestrial relations. As a first step, the Workshop on the Role of the Electrodynamics of the Middle Atmosphere on Solar-Terrestrial Coupling was held to review the present status and define recommendations for future MAE research.
Electrodynamics of the middle atmosphere: Superpressure balloon program
NASA Technical Reports Server (NTRS)
Holzworth, Robert H.
1987-01-01
In this experiment a comprehensive set of electrical parameters were measured during eight long duration flights in the southern hemisphere stratosphere. These flight resulted in the largest data set ever collected from the stratosphere. The stratosphere has never been electrodynamically sampled in the systematic manner before. New discoveries include short term variability in the planetary scale electric current system, the unexpected observation of stratospheric conductivity variations over thunderstorms and the observation of direct stratospheric conductivity variations following a relatively small solar flare. Major statistical studies were conducted of the large scale current systems, the stratospheric conductivity and the neutral gravity waves (from pressure and temperature data) using the entire data set.
Space Environmental Testing of the Electrodynamic Dust Shield Technology
NASA Technical Reports Server (NTRS)
Calle, Carlos I.; Mackey, P. J.; Hogue, M. D.; Johansen, M .R.; Yim, H.; Delaune, P. B.; Clements, J. S.
2013-01-01
NASA's exploration missions to Mars and the moon may be jeopardized by dust that will adhere to surfaces of (a) Optical systems, viewports and solar panels, (b) Thermal radiators, (c) Instrumentation, and (d) Spacesuits. We have developed an active dust mitigation technology, the Electrodynamic Dust Shield, a multilayer coating that can remove dust and also prevents its accumulation Extensive testing in simulated laboratory environments and on a reduced gravity flight shows that high dust removal performance can be achieved Long duration exposure to the space environment as part of the MISSE-X payload will validate the technology for lunar missions.
Capabilities of electrodynamic shakers when used for mechanical shock testing
NASA Technical Reports Server (NTRS)
Keegan, W. B.
1973-01-01
The results of a research task to investigate the capabilities of electrodynamic vibrators (shakers) to perform mechanical shock tests are presented. The simulation method employed was that of developing a transient whose shock response spectrum matched the desired shock response spectrum. Areas investigated included the maximum amplitude capabilities of the shaker systems, the ability to control the shape of the resultant shock response spectrum, the response levels induced at frequencies outside the controlled bandwidth, and the nonlinearities in structural response induced by a change in test level.
Spin Pumping in Electrodynamically Coupled Magnon-Photon Systems
NASA Astrophysics Data System (ADS)
Bai, Lihui; Harder, M.; Chen, Y. P.; Fan, X.; Xiao, J. Q.; Hu, C.-M.
2015-06-01
We use electrical detection, in combination with microwave transmission, to investigate both resonant and nonresonant magnon-photon coupling at room temperature. Spin pumping in a dynamically coupled magnon-photon system is found to be distinctly different from previous experiments. Characteristic coupling features such as modes anticrossing, linewidth evolution, peculiar line shape, and resonance broadening are systematically measured and consistently analyzed by a theoretical model set on the foundation of classical electrodynamic coupling. Our experimental and theoretical approach paves the way for pursuing microwave coherent manipulation of pure spin current via the combination of spin pumping and magnon-photon coupling.
On Irreversibility and Radiation in Classical Electrodynamics of Point Particles
NASA Astrophysics Data System (ADS)
Bauer, Gernot; Deckert, Dirk-André; Dürr, Detlef; Hinrichs, Günter
2013-09-01
The direct interaction theory of electromagnetism, also known as Wheeler-Feynman electrodynamics, is often misinterpreted and found unappealing because of its reference to the absorber and, more importantly, to the so-called absorber condition. Here we remark that the absorber condition is indeed questionable and presumably not relevant for the explanation of irreversible radiation phenomena in our universe. What is relevant and deserves further scrutiny is the emergent effective description of a source particle in an environment. We therefore rephrase what we consider the relevant calculation by Wheeler and Feynman and comment on the status of the theory.
Applications of the Electrodynamic Tether to Interstellar Travel
NASA Technical Reports Server (NTRS)
Matloff, Gregory L.; Johnson, Les
2005-01-01
After considering relevant properties of the local interstellar medium and defining a sample interstellar mission, this paper considers possible interstellar applications of the electrodynamic tether, or EDT. These include use of the EDT to provide on-board power and affect trajectory modifications and direct application of the EDT to starship acceleration. It is demonstrated that comparatively modest EDTs can provide substantial quantities of on-board power, if combined with a large-area electron-collection device such as the Cassenti toroidal-field ramscoop. More substantial tethers can be used to accomplish large-radius thrustless turns. Direct application of the EDT to starship acceleration is apparently infeasible.
One-way quantum computation with circuit quantum electrodynamics
Wu Chunwang; Han Yang; Chen Pingxing; Li Chengzu; Zhong Xiaojun
2010-03-15
In this Brief Report, we propose a potential scheme to implement one-way quantum computation with circuit quantum electrodynamics (QED). Large cluster states of charge qubits can be generated in just one step with a superconducting transmission line resonator (TLR) playing the role of a dispersive coupler. A single-qubit measurement in the arbitrary basis can be implemented using a single electron transistor with the help of one-qubit gates. By examining the main decoherence sources, we show that circuit QED is a promising architecture for one-way quantum computation.
Single-photon transistor in circuit quantum electrodynamics.
Neumeier, Lukas; Leib, Martin; Hartmann, Michael J
2013-08-09
We introduce a circuit quantum electrodynamical setup for a "single-photon" transistor. In our approach photons propagate in two open transmission lines that are coupled via two interacting transmon qubits. The interaction is such that no photons are exchanged between the two transmission lines but a single photon in one line can completely block or enable the propagation of photons in the other line. High on-off ratios can be achieved for feasible experimental parameters. Our approach is inherently scalable as all photon pulses can have the same pulse shape and carrier frequency such that output signals of one transistor can be input signals for a consecutive transistor.
Relativistic and quantum electrodynamics effects in the helium pair potential.
Przybytek, M; Cencek, W; Komasa, J; Łach, G; Jeziorski, B; Szalewicz, K
2010-05-07
The helium pair potential was computed including relativistic and quantum electrodynamics contributions as well as improved accuracy adiabatic ones. Accurate asymptotic expansions were used for large distances R. Error estimates show that the present potential is more accurate than any published to date. The computed dissociation energy and the average R for the (4)He(2) bound state are 1.62+/-0.03 mK and 47.1+/-0.5 A. These values can be compared with the measured ones: 1.1(-0.2)(+0.3) mK and 52+/-4 A [R. E. Grisenti, Phys. Rev. Lett. 85, 2284 (2000)].
8-Spinors and structure of solitons in generalized Mie electrodynamics
Rybakov, Yu. P.
2013-02-15
A generalization of Mie electrodynamics is considered. It includes a 8-spinor field and higher powers of the Mie invariant A{sub {mu}}A{sup {mu}}. Particular topological properties of 8-spinors are indicated and are associated with the existence of the remarkable Brioschi identity of eight squares, which permits deriving a natural 8-spinor unification of the Skyrme model of baryons and the Faddeev model of leptons, these particles being treated as topological solitons. Two types of soliton configurations admitted by the model are constructed. These are charged static and neutral lightlike (luxons) ones.
Quantum electrodynamics vacuum polarization modification of photon acceleration in plasma
Bu Zhigang; Ji Peiyong
2010-07-15
The modification of photon frequency shifting based on taking into account the nonlinear quantum electrodynamics vacuum properties in plasma is studied. Motion equations of a laser field propagating in a plasma are derived from the Heisenberg-Euler Lagrangian density. It is found that besides the classical density perturbation of the plasma electrons, the energy density perturbation of the laser field will induce the frequency shifting via the ponderomotive force of the laser field on the vacuum. In addition it is shown that the electron density will be suppressed, which is attributed to a screening effect on the plasma electrons via the quantum vacuum polarization.
A simple electrodynamic model of a dust devil
NASA Astrophysics Data System (ADS)
Farrell, William M.; Delory, Greg T.; Cummer, Steven A.; Marshall, John R.
2003-10-01
We present an electrodynamic model of a dust devil applying a similar methodology as performed previously for charging in terrestrial thunderstorms. While thunderstorm processes focus on inductive charging between large graupel and smaller ice and water droplets, we tailor the model to focus on the electric charge transfer between dust grains of different sizes and compositions. We specifically compare and contrast the triboelectric dust charging processes presented previously in Melnik and Parrot [1998] and Desch and Cuzzi [2000] in the development of macroscopic dust devil electric fields. We find that large vertical E-fields (~20 kV/m) can develop in the devil.
Electrodynamic boundary conditions for planar arrays of thin magnetic elements
Lisenkov, Ivan; Tyberkevych, Vasyl; Slavin, Andrei; Nikitov, Sergei
2015-08-24
Approximate electrodynamic boundary conditions are derived for an array of dipolarly coupled magnetic elements. It is assumed that the elements' thickness is small compared to the wavelength of an electromagnetic wave in a free space. The boundary conditions relate electric and magnetic fields existing at the top and bottom sides of the array through the averaged uniform dynamic magnetization of the array. This dynamic magnetization is determined by the collective dynamic eigen-excitations (spin wave modes) of the array and is found using the external magnetic susceptibility tensor. The problem of oblique scattering of a plane electromagnetic wave on the array is considered to illustrate the use of the derived boundary conditions.
Lyapunov Orbits in the Jupiter System Using Electrodynamic Tethers
NASA Technical Reports Server (NTRS)
Bokelmann, Kevin; Russell, Ryan P.; Lantoine, Gregory
2013-01-01
Various researchers have proposed the use of electrodynamic tethers for power generation and capture from interplanetary transfers. The effect of tether forces on periodic orbits in Jupiter-satellite systems are investigated. A perturbation force is added to the restricted three-body problem model and a series of simplifications allows development of a conservative system that retains the Jacobi integral. Expressions are developed to find modified locations of equilibrium positions. Modified families of Lyapunov orbits are generated as functions of tether size and Jacobi integral. Zero velocity curves and stability analyses are used to evaluate the dynamical properties of tether-modified orbits.
Gravito-electrodynamics and the structure of planetary ring systems
NASA Technical Reports Server (NTRS)
Mendis, D. A.
1984-01-01
Recent spacecraft observations of the Saturnian and Jovian ring systems have highlighted a plethora of interesting new phenomena associated with those regions containing fine (micron and sub-micron sized) dust. Recognizing that these dust grains, by virtue of being immersed within the planetary magnetospheres, are electrostatically charged to the point that they experience comparable gravitational and electric forces, a new 'gravito-electrodynamic' theory has been developed to describe their dynamics. This theory has been successful in explaining all these phenomena in a systematic way. In this review, the basic model and its range of validity are outlined, and its application to the Saturnian and Jovian ring systems are discussed.
Quantum electrodynamics, high-resolution spectroscopy and fundamental constants
NASA Astrophysics Data System (ADS)
Karshenboim, Savely G.; Ivanov, Vladimir G.
2017-01-01
Recent progress in high-resolution spectroscopy has delivered us a variety of accurate optical results, which can be used for the determination of the atomic fundamental constants and for constraining their possible time variation. We present a brief overview of the results discussing in particular, the determination of the Rydberg constant, the relative atomic weight of the electron and proton, their mass ratio and the fine structure constant. Many individual results on those constants are obtained with use of quantum electrodynamics, and we discuss which sectors of QED are involved. We derive constraints on a possible time variation of the fine structure constants and me/mp.
NASA Technical Reports Server (NTRS)
Ussery, Wilfred T.; MacCalla, Eric; MacCalla, Johnetta; Elnimeiri, Mahjoub; Goldsmith, Myron; Polk, Sharon Madison; Jenkins, Mozella; Bragg, Robert H.
1996-01-01
Recent breakthroughs in several different fields now make it possible to incorporate the use of superconducting magnets in structures in ways which enhance the performance of structural members or components of structural systems in general and Maglev guideway mega-structures in particular. The building of structural systems which connect appropriately scaled superconducting magnets with the post-tensioned tensile components of beams, girders, or columns would, if coupled with 'state of the art' structure monitoring, feedback and control systems, and advanced computer software, constitute a distinct new generation of structures that would possess the unique characteristic of being heuristic and demand or live-load responsive. The holistic integration of powerful superconducting magnets in structures so that they do actual structural work, creates a class of 'technologically endowed' structures that, in part - literally substitute superconductive electric power and magnetism for concrete and steel. The research and development engineering, and architectural design issues associated with such 'technologically endowed' structural system can now be conceptualized, designed, computer simulates built and tested. The Maglev guideway mega-structure delineated herein incorporates these concepts, and is designed for operation in the median strip of U.S. Interstate Highway 5 from San Diego to Seattle an Vancouver, and possibly on to Fairbanks, Alaska. This system also fits in the median strip of U.S. Interstate Highway 55 and 95 North-South, and 80 and 10, East-West. As a Western Region 'Peace Dividend' project, it could become a National or Bi-National research, design and build, super turnkey project that would create thousands of jobs by applying superconducting, material science, electronic aerospace and other defense industry technologies to a multi-vehicle, multi-use Maglev guideway megastructure that integrates urban mass transit Lower Speed (0-100 mph), High Speed
Charged relativistic fluids and non-linear electrodynamics
NASA Astrophysics Data System (ADS)
Dereli, T.; Tucker, R. W.
2010-01-01
The electromagnetic fields in Maxwell's theory satisfy linear equations in the classical vacuum. This is modified in classical non-linear electrodynamic theories. To date there has been little experimental evidence that any of these modified theories are tenable. However with the advent of high-intensity lasers and powerful laboratory magnetic fields this situation may be changing. We argue that an approach involving the self-consistent relativistic motion of a smooth fluid-like distribution of matter (composed of a large number of charged or neutral particles) in an electromagnetic field offers a viable theoretical framework in which to explore the experimental consequences of non-linear electrodynamics. We construct such a model based on the theory of Born and Infeld and suggest that a simple laboratory experiment involving the propagation of light in a static magnetic field could be used to place bounds on the fundamental coupling in that theory. Such a framework has many applications including a new description of the motion of particles in modern accelerators and plasmas as well as phenomena in astrophysical contexts such as in the environment of magnetars, quasars and gamma-ray bursts.
Electrostatic spherically symmetric configurations in gravitating nonlinear electrodynamics
Diaz-Alonso, J.; Rubiera-Garcia, D.
2010-03-15
We perform a study of the gravitating electrostatic spherically symmetric (G-ESS) solutions of Einstein field equations minimally coupled to generalized nonlinear Abelian gauge models in three space dimensions. These models are defined by Lagrangian densities which are general functions of the gauge field invariants, restricted by some physical conditions of admissibility. They include the class of nonlinear electrodynamics supporting electrostatic spherically symmetric (ESS) nontopological soliton solutions in absence of gravity. We establish that the qualitative structure of the G-ESS solutions of admissible models is fully characterized by the asymptotic and central-field behaviors of their ESS solutions in flat space (or, equivalently, by the behavior of the Lagrangian densities in vacuum and on the point of the boundary of their domain of definition, where the second gauge invariant vanishes). The structure of these G-ESS configurations for admissible models supporting divergent-energy ESS solutions in flat space is qualitatively the same as in the Reissner-Nordstroem case. In contrast, the G-ESS configurations of the models supporting finite-energy ESS solutions in flat space exhibit new qualitative features, which are discussed in terms of the Arnowitt-Deser-Misner mass, the charge, and the soliton energy. Most of the results concerning well-known models, such as the electrodynamics of Maxwell, Born-Infeld, and the Euler-Heisenberg effective Lagrangian of QED, minimally coupled to gravitation, are shown to be corollaries of general statements of this analysis.
Hollow cathode-based plasma contactor experiments for electrodynamic tether
NASA Technical Reports Server (NTRS)
Patterson, Michael J.
1987-01-01
The role plasma contactors play in effective electrodynamic tether operation is discussed. Hollow cathodes and hollow cathode-based plasma sources have been identified as leading candidates for the electrodynamic tether plasma contactor. Present experimental efforts to evaluate the suitability of these devices as plasma contactors are reviewed. This research includes the definition of preliminary plasma contactor designs, and the characterization of their operation as electron collectors from a simulated space plasma. The discovery of an 'ignited mode' regime of high contactor efficiency and low impedance is discussed, as well as is the application of recent models of the plasma coupling process to contactor operation. Results indicate that ampere-level electron currents can be exchanged between hollow cathode-based plasma contactors and a dilute plasma in this regime. A discussion of design considerations for plasma contactors is given which includes expressions defining the total mass flow rate and power requirements of plasma contactors operating in both the cathodic and anodic regimes, and correlation of this to the tether current. Finally, future ground and spaceflight experiments are proposed to resolve critical issues of plasma contactor operation.
Hybrid circuit cavity quantum electrodynamics with a micromechanical resonator.
Pirkkalainen, J-M; Cho, S U; Li, Jian; Paraoanu, G S; Hakonen, P J; Sillanpää, M A
2013-02-14
Hybrid quantum systems with inherently distinct degrees of freedom have a key role in many physical phenomena. Well-known examples include cavity quantum electrodynamics, trapped ions, and electrons and phonons in the solid state. In those systems, strong coupling makes the constituents lose their individual character and form dressed states, which represent a collective form of dynamics. As well as having fundamental importance, hybrid systems also have practical applications, notably in the emerging field of quantum information control. A promising approach is to combine long-lived atomic states with the accessible electrical degrees of freedom in superconducting cavities and quantum bits (qubits). Here we integrate circuit cavity quantum electrodynamics with phonons. Apart from coupling to a microwave cavity, our superconducting transmon qubit, consisting of tunnel junctions and a capacitor, interacts with a phonon mode in a micromechanical resonator, and thus acts like an atom coupled to two different cavities. We measure the phonon Stark shift, as well as the splitting of the qubit spectral line into motional sidebands, which feature transitions between the dressed electromechanical states. In the time domain, we observe coherent conversion of qubit excitation to phonons as sideband Rabi oscillations. This is a model system with potential for a quantum interface, which may allow for storage of quantum information in long-lived phonon states, coupling to optical photons or for investigations of strongly coupled quantum systems near the classical limit.
Gauge covariant fermion propagator in quenched, chirally symmetric quantum electrodynamics
Roberts, C.D.; Dong, Z.; Munczek, H.J.
1995-08-01
The chirally symmetric solution of the massless, quenched, Dyson-Schwinger equation (DSE) for the fermion propagator in three- and four-dimensional quantum electrodynamics was obtained. The DSEs are a valuable nonperturbative tool for studying field theories. In recent years a good deal of progress was made in addressing the limitations of the DSE approach in the study of Abelian gauge theories. Key to this progress is an understanding of the role of the dressed fermion/gauge-boson vertex in ensuring gauge covariance and multiplicative renormalizability of the solution of the fermion DSE. The solutions we obtain are manifestly gauge covariant and a general gauge covariance constraint on the fermion/gauge-boson vertex is presented, which motivates a vertex Ansatz that, for the first time, both satisfies the Ward identity when the fermion self-mass is zero and ensures gauge covariance of the fermion propagator. This research facilitates gauge-invariant, nonperturbative studies of continuum quantum electrodynamics and has already been used by others in studies of the chiral phase transition.
Experimental Evaluation of Three Designs of Electrodynamic Flexural Transducers
Eriksson, Tobias J. R.; Laws, Michael; Kang, Lei; Fan, Yichao; Ramadas, Sivaram N.; Dixon, Steve
2016-01-01
Three designs for electrodynamic flexural transducers (EDFT) for air-coupled ultrasonics are presented and compared. An all-metal housing was used for robustness, which makes the designs more suitable for industrial applications. The housing is designed such that there is a thin metal plate at the front, with a fundamental flexural vibration mode at ∼50 kHz. By using a flexural resonance mode, good coupling to the load medium was achieved without the use of matching layers. The front radiating plate is actuated electrodynamically by a spiral coil inside the transducer, which produces an induced magnetic field when an AC current is applied to it. The transducers operate without the use of piezoelectric materials, which can simplify manufacturing and prolong the lifetime of the transducers, as well as open up possibilities for high-temperature applications. The results show that different designs perform best for the generation and reception of ultrasound. All three designs produced large acoustic pressure outputs, with a recorded sound pressure level (SPL) above 120 dB at a 40 cm distance from the highest output transducer. The sensitivity of the transducers was low, however, with single shot signal-to-noise ratio (SNR)≃15 dB in transmit–receive mode, with transmitter and receiver 40 cm apart. PMID:27571075
Electrodynamics of the Middle Atmosphere: Superpressure Balloon Program
NASA Technical Reports Server (NTRS)
Holzworth, Robert H.
1990-01-01
This project called Electrodynamics of the Middle Atmosphere (EMA): Superpressure Balloon Program was begun by the PI at the Aerospace Corporation in Los Angeles under joint NSF and NASA funding originally combined in one grant ATM80-17071 and has continued at the University of Washington under grants ATM8212283, ATM84-11326 and ATM86-15628 and NASA grants NAGW-724 and NAGS-635. In the EMA experiment a comprehensive set of electrical parameters was measured during eight long-duration balloon flights in the Southern Hemisphere stratosphere. These flights resulted in the largest vector electric field data set ever collected from the stratosphere which has been a treasure-trove of new phenomena. Since the stratosphere has never been electrodynamically sampled in this systematic manner before, it is perhaps not surprising that several new discoveries have been made and reported. Another way to measure the success of this first EMA project is to note that all together the total data rate was about 1 bit/sec/payload amounting to 12 MBytes (1/3 of 1 standard 1600 BPI magnetic tape) which nevertheless has resulted in 14 papers and 2 masters theses (so far! . Ten of these papers and one masters thesis specifically acknowledge the support by NASA grant NAGS-635 are discussed herein.
Implementation Options for the PROPEL Electrodynamic Tether Demonstration Mission
NASA Technical Reports Server (NTRS)
Bilen, Sven G.; Johnson, C. Les; Gilchrist, Brian E.; Hoyt, Robert P.; Elder, Craig H.; Fuhrhop, Keith P.; Scadera, Michael; Stone, Nobie
2014-01-01
The PROPEL ("Propulsion using Electrodynamics") flight demonstration mission concept will demonstrate the use of an electrodynamic tether (EDT) for generating thrust, which will allow the propulsion system to overcome the limitations of the rocket equation. The mission concept has been developed by a team of government, industry, and academia partners led by NASA Marshall Space Flight Center (MSFC). PROPEL is being designed for versatility of the EDT system with multiple end users in mind and to be flexible with respect to platform. Previously, we reported on a comprehensive mission design for PROPEL with a mission duration of six months or longer with multiple mission goals including demonstration of significant boost, deboost, inclination change, and drag make-up activities. To explore a range of possible configurations, primarily driven by cost considerations, other mission concept designs have been pursued. In partnership with the NASA's Office of Chief Technologist (OCT) Game Changing Program, NASA MSFC Leadership, and the MSFC Advanced Concepts Office, a mission concept design was developed for a near-term EDT propulsion flight validation mission. The Electrodynamic Tether Propulsion Study (ETPS) defined an EDT propulsion system capable of very large delta-V for use on future missions developed by NASA, DoD, and commercial customers. To demonstrate the feasibility of an ETPS, the study focused on a space demonstration mission concept design with configuration of a pair of tethered satellite busses, one of which is the Japanese H-II Transfer Vehicle (HTV). The HTV would fly its standard ISS resupply mission. When resupply mission is complete, the ISS reconfigures and releases the HTV to perform the EDT experiment at safe orbital altitudes below the ISS. Though the focus of this particular mission concept design addresses a scenario involving the HTV or a similar vehicle, the propulsion system's capability is relevant to a number of applications, as noted above
Quantum electrodynamic corrections for valence electrons in Eka-Hg
NASA Astrophysics Data System (ADS)
Golovko, O. A.; Goidenko, I. A.; Tupitsyn, I. I.
2008-05-01
The quantum electrodynamic (QED) corrections to the coupling energy of valence electrons in heavy and superheavy nuclei are calculated in the effective local-potential approximation, as well as by the Hartree-Fock-Dirac self-consistent method. It is clearly shown that the contribution from the QED corrections is within the accuracy of modern calculations, which do not take into account QED effects. It is shown that, in certain cases, to exactly calculate the coupling energy of electrons in heavy and superheavy atoms, it is necessary to take into account the self-consistency, which shows that the inaccuracy of the use of the method of the effective local potential in calculations of QED effects can exceed 10%, which is also within the limits of calculations of the coupling energy without taking into account QED effects.
Quantum-to-classical transition in cavity quantum electrodynamics.
Fink, J M; Steffen, L; Studer, P; Bishop, Lev S; Baur, M; Bianchetti, R; Bozyigit, D; Lang, C; Filipp, S; Leek, P J; Wallraff, A
2010-10-15
The quantum properties of electromagnetic, mechanical or other harmonic oscillators can be revealed by investigating their strong coherent coupling to a single quantum two level system in an approach known as cavity quantum electrodynamics (QED). At temperatures much lower than the characteristic energy level spacing the observation of vacuum Rabi oscillations or mode splittings with one or a few quanta asserts the quantum nature of the oscillator. Here, we study how the classical response of a cavity QED system emerges from the quantum one when its thermal occupation-or effective temperature-is raised gradually over 5 orders of magnitude. In this way we explore in detail the continuous quantum-to-classical crossover and demonstrate how to extract effective cavity field temperatures from both spectroscopic and time-resolved vacuum Rabi measurements.
Nonperturbative renormalization of scalar quantum electrodynamics in d=3
Dimock, J.
2015-10-15
For scalar quantum electrodynamics on a three-dimensional toroidal lattice with a fine lattice spacing, we consider the renormalization problem of choosing counter terms depending on the lattice spacing, so that the theory stays finite as the spacing goes to zero. We employ a renormalization group method which analyzes the flow of the mass and the vacuum energy as a problem in discrete dynamical systems. The main result is that counter terms can be chosen so that at the end of the iteration these quantities take preassigned values. No use is made of perturbation theory. The renormalization group transformations are defined with bounded fields, an approximation which can be justified in Balaban’s approach to the renormalization group.
Cavity quantum electrodynamics with Anderson-localized modes.
Sapienza, Luca; Thyrrestrup, Henri; Stobbe, Søren; Garcia, Pedro David; Smolka, Stephan; Lodahl, Peter
2010-03-12
A major challenge in quantum optics and quantum information technology is to enhance the interaction between single photons and single quantum emitters. This requires highly engineered optical cavities that are inherently sensitive to fabrication imperfections. We have demonstrated a fundamentally different approach in which disorder is used as a resource rather than a nuisance. We generated strongly confined Anderson-localized cavity modes by deliberately adding disorder to photonic crystal waveguides. The emission rate of a semiconductor quantum dot embedded in the waveguide was enhanced by a factor of 15 on resonance with the Anderson-localized mode, and 94% of the emitted single photons coupled to the mode. Disordered photonic media thus provide an efficient platform for quantum electrodynamics, offering an approach to inherently disorder-robust quantum information devices.
Quantum electrodynamics and plasmonic resonance of metallic nanostructures.
Zhang, Mingliang; Xiang, Hongping; Zhang, Xu; Lu, Gang
2016-04-20
Plasmonic resonance of a metallic nanostructure results from coherent motion of its conduction electrons driven by incident light. At the resonance, the induced dipole in the nanostructure is proportional to the number of the conduction electrons, hence 10(7) times larger than that in an atom. The interaction energy between the induced dipole and fluctuating virtual field of the incident light can reach a few tenths of an eV. Therefore, the classical electromagnetism dominating the field may become inadequate. We propose that quantum electrodynamics (QED) may be used as a fundamental theory to describe the interaction between the virtual field and the oscillating electrons. Based on QED, we derive analytic expressions for the plasmon resonant frequency, which depends on three easily accessible material parameters. The analytic theory reproduces very well the experimental data, and can be used in rational design of materials for plasmonic applications.
Black hole as a magnetic monopole within exponential nonlinear electrodynamics
NASA Astrophysics Data System (ADS)
Kruglov, S. I.
2017-03-01
We perform the gauge covariant quantization of the exponential model of nonlinear electrodynamics. Magnetically charged black holes, in the framework of our model are considered, and the regular black hole solution is obtained in general relativity. The asymptotic black hole solution at r → ∞ is found. We calculate the magnetic mass of the black hole and the metric function which are expressed via the parameter β of the model and the magnetic charge. The thermodynamic properties and thermal stability of regular black holes are analysed. We calculate the Hawking temperature of black holes and their heat capacity at the constant magnetic charge. We find a point where the temperature changes the sign that corresponds to the first-order phase transition. It is shown that at critical point, where the heat capacity diverges, there is a phase transition of the second-order. We obtain the parameters of the model when the black hole is stable.
Quantized fluctuational electrodynamics for three-dimensional plasmonic structures
NASA Astrophysics Data System (ADS)
Partanen, Mikko; Häyrynen, Teppo; Tulkki, Jukka; Oksanen, Jani
2017-01-01
We recently introduced a quantized fluctuational electrodynamics (QFED) formalism that provides a physically insightful definition of an effective position-dependent photon-number operator and the associated ladder operators. However, this far the formalism has been applicable only for the normal incidence of the electromagnetic field in planar structures. In this work, we overcome the main limitation of the one-dimensional QFED formalism by extending the model to three dimensions, allowing us to use the QFED method to study, e.g., plasmonic structures. To demonstrate the benefits of the developed formalism, we apply it to study the local steady-state photon numbers and field temperatures in a light-emitting near-surface InGaN quantum-well structure with a metallic coating supporting surface plasmons.
Quantum Electrodynamics Effects in Rovibrational Spectra of Molecular Hydrogen.
Komasa, Jacek; Piszczatowski, Konrad; Łach, Grzegorz; Przybytek, Michał; Jeziorski, Bogumił; Pachucki, Krzysztof
2011-10-11
The dissociation energies from all rovibrational levels of H2 and D2 in the ground electronic state are calculated with high accuracy by including relativistic and quantum electrodynamics (QED) effects in the nonadiabatic treatment of the nuclear motion. For D2, the obtained energies have theoretical uncertainties of 0.001 cm(-1). For H2, similar uncertainties are for the lowest levels, while for the higher ones the uncertainty increases to 0.005 cm(-1). Very good agreement with recent high-resolution measurements of the rotational v = 0 levels of H2, including states with large angular momentum J, is achieved. This agreement would not have been possible without accurate evaluation of the relativistic and QED contributions and may be viewed as the first observation of the QED effects, mainly the electron self-energy, in a molecular spectrum. For several electric quadrupole transitions, we still observe certain disagreement with experimental results, which remains to be explained.
Hydrodynamic view of electrodynamics: energy rays and electromagnetic effective stress
NASA Astrophysics Data System (ADS)
Chou, Chia-Chun; Wyatt, Robert E.
2011-06-01
Energy rays ('photon trajectories') based upon the hydrodynamic formulation of electrodynamics are presented for time-dependent electromagnetic wave propagation. We derive Cauchy's equation of motion for the electromagnetic effective force governing the dynamics of energy rays. The effective force generated by the electromagnetic effective stress provides a surface force acting on the energy fluid element. For the head-on collision of two electromagnetic Gaussian pulses, the electromagnetic effective force, analogous to the role played by the quantum force in Bohmian mechanics, guides these non-crossing energy rays. For an electromagnetic pulse traveling from free space to a dielectric medium, the energy rays guided by the electromagnetic effective stress display reflection and refraction at the interface.
Thermodynamics of anisotropic emergent universe in nonlinear electrodynamics
NASA Astrophysics Data System (ADS)
Sharif, M.; Sarwar, Ayesha
2016-07-01
In this paper, we study the emergent universe (EU) with interacting fluids in the background of Bianchi type I (BI) universe model. For this purpose, we consider polytropic equation of state (EoS) which constitutes three non-interacting fluids. In order to check the viability of the cosmological models, we take a two-fluid model interacting with dust fluid and a three-fluid model in which each fluid has nonlinear EoS interacting at t ≥ t0. It turns out that both models are realistic cosmological viable. We also check the validity of the generalized second law of thermodynamics (GSLT) for EU with interacting fluids. Finally, we study its validity in the framework of nonlinear electrodynamics (NLED) on apparent horizon.
Optical gyrotropy from axion electrodynamics in momentum space.
Zhong, Shudan; Orenstein, Joseph; Moore, Joel E
2015-09-11
Several emergent phenomena and phases in solids arise from configurations of the electronic Berry phase in momentum space that are similar to gauge field configurations in real space such as magnetic monopoles. We show that the momentum-space analogue of the "axion electrodynamics" term E·B plays a fundamental role in a unified theory of Berry-phase contributions to optical gyrotropy in time-reversal invariant materials and the chiral magnetic effect. The Berry-phase mechanism predicts that the rotatory power along the optic axes of a crystal must sum to zero, a constraint beyond that stipulated by point-group symmetry, but observed to high accuracy in classic experimental observations on alpha quartz. Furthermore, the Berry mechanism provides a microscopic basis for the surface conductance at the interface between gyrotropic and nongyrotropic media.
A thermosphere/ionosphere general circulation model with coupled electrodynamics
NASA Technical Reports Server (NTRS)
Richmond, A. D.; Ridley, E. C.; Roble, R. G.
1992-01-01
A new simulation model of upper atmospheric dynamics is presented that includes self-consistent electrodynamic interactions between the thermosphere and ionosphere. This model calculates the dynamo effects of thermospheric winds, and uses the resultant electric fields and currents in calculating the neutral and plasma dynamics. A realistic geomagnetic field geometry is used. Sample simulations for solar maximum equinox conditions illustrate two previously predicted effects of the feedback. Near the magnetic equator, the afternoon uplift of the ionosphere by an eastward electric field reduces ion drag on the neutral wind, so that relatively strong eastward winds can occur in the evening. In addition, a vertical electric field is generated by the low-latitude wind, which produces east-west plasma drifts in the same direction as the wind, further reducing the ion drag and resulting in stronger zonal winds.
Electrodynamics of the stratosphere using 5000 cu m superpressure balloons
NASA Technical Reports Server (NTRS)
Holzworth, R. H.
1983-01-01
The Electrodynamics of the Middle Atmosphere research project encompasses the design of a microprocessor-controlled payload and the launch of up to eight small superpressure balloons in the 1982-1984 period. The primary payload instrument will measure the vector electric field from dc to 10 kHz, and the payloads will include instruments measuring local ionization, electrical conductivity, magnetic field, and temperature and pressure fluctuations. In addition, optical lightning will be recorded. The simultaneous measurement of these stratospheric parameters by several balloons, for periods extending over several solar rotations, will allow the study of electrical coupling between atmosphere and magnetosphere, of global current systems, and of global response to solar flares and magnetospheric storms.
Simulation of the hydrogen ground state in stochastic electrodynamics
NASA Astrophysics Data System (ADS)
Nieuwenhuizen, Theo M.; Liska, Matthew T. P.
2015-10-01
Stochastic electrodynamics is a classical theory which assumes that the physical vacuum consists of classical stochastic fields with average energy \\frac{1}{2}{{\\hslash }}ω in each mode, i.e., the zero-point Planck spectrum. While this classical theory explains many quantum phenomena related to harmonic oscillator problems, hard results on nonlinear systems are still lacking. In this work the hydrogen ground state is studied by numerically solving the Abraham-Lorentz equation in the dipole approximation. First the stochastic Gaussian field is represented by a sum over Gaussian frequency components, next the dynamics is solved numerically using OpenCL. The approach improves on work by Cole and Zou 2003 by treating the full 3d problem and reaching longer simulation times. The results are compared with a conjecture for the ground state phase space density. Though short time results suggest a trend towards confirmation, in all attempted modellings the atom ionises at longer times.
Spontaneous emission in confined space according to stochastic electrodynamics
NASA Astrophysics Data System (ADS)
França, H. M.; Marshall, T. W.; Santos, E.
1992-05-01
Modeling an atomic excited state as a simple charged dipole oscillator immersed in a random (zero-point) radiation, we discuss the effects of two metallic plates on the properties of a microscopic system. The spectral distribution of the zero-point electromagnetic field, characteristic of stochastic electrodynamics, and the rate of emission of the oscillator are modified by the boundaries of the cavity. As a result, the lifetime of the oscillator excited states are different from the free-space values. A comparison with recent experimental results [W. Jhe et al., Phys. Rev. Lett. 58, 666 (1987)] exhibiting suppression of spontaneous decay of excited Cs atoms shows a good agreement with our simplified model calculation.
Entangling distant resonant exchange qubits via circuit quantum electrodynamics
NASA Astrophysics Data System (ADS)
Srinivasa, Vanita; Taylor, Jacob M.; Tahan, Charles
Enabling modularity within a quantum information processing device relies on robust entanglement of coherent qubits at macroscopic distances. To address this challenge, we investigate theoretically a hybrid quantum system consisting of spatially separated resonant exchange qubits, defined in three-electron semiconductor triple quantum dots, that are coupled via a superconducting transmission line resonator. By analyzing three specific approaches drawn from circuit quantum electrodynamics and Hartmann-Hahn double resonance techniques for implementing resonator-mediated two-qubit entangling gates in both dispersive and resonant regimes, we show that methods for entangling superconducting qubits map directly to resonant exchange qubits. We also calculate the rate of relaxation via phonons for resonant exchange qubits in silicon triple dots and show that such an implementation is particularly well-suited to achieving the strong coupling regime. Our approach combines the robustness of encoded spin qubits in silicon with the rapid and robust long-range entanglement provided by circuit QED systems.
Entangling distant resonant exchange qubits via circuit quantum electrodynamics
NASA Astrophysics Data System (ADS)
Srinivasa, V.; Taylor, J. M.; Tahan, Charles
2016-11-01
We investigate a hybrid quantum system consisting of spatially separated resonant exchange qubits, defined in three-electron semiconductor triple quantum dots, that are coupled via a superconducting transmission line resonator. Drawing on methods from circuit quantum electrodynamics and Hartmann-Hahn double resonance techniques, we analyze three specific approaches for implementing resonator-mediated two-qubit entangling gates in both dispersive and resonant regimes of interaction. We calculate entangling gate fidelities as well as the rate of relaxation via phonons for resonant exchange qubits in silicon triple dots and show that such an implementation is particularly well suited to achieving the strong coupling regime. Our approach combines the favorable coherence properties of encoded spin qubits in silicon with the rapid and robust long-range entanglement provided by circuit QED systems.
Ill posedness of force-free electrodynamics in Euler potentials
NASA Astrophysics Data System (ADS)
Reula, Oscar A.; Rubio, Marcelo E.
2017-03-01
We prove that the initial value problem for force-free electrodynamics in Euler variables is not well posed. We establish this result by showing that a well-posedness criterion provided by Kreiss fails to hold for this theory, and using a theorem provided by Strang. To show the nature of the problem we display a particular bounded (in Sobolev norms) sequence of initial data for the force-free equations such that at any given time as close to zero as one wishes, the corresponding evolution sequence is not bounded. Thus, the force-free evolution is noncontinuous in that norm with respect to the initial data. We furthermore prove that this problem is also ill-posed in the Leray-Ohya sense.
Quantum-electrodynamical parametric instability in the incoherent photon gas.
Wang, Yunliang; Shukla, P K; Eliasson, B
2013-02-01
We present a theory for the quantum-electrodynamical (QED) parametric scattering instability of an intense photon pulse in an incoherent radiation background. The pump electromagnetic (EM) wave can decay into a scattered daughter EM wave and an acousticlike wave due to the QED vacuum polarization nonlinearity. By a linear instability analysis we obtain a nonlinear dispersion relation for the growth rate of the scattering instability. The nonlinear QED scattering instability can give rise to the exchange of orbital angular momentum between intense Laguerre-Gaussian mode photon pulses and the two daughter waves, which may be a useful method to detect the highly energetic photon gases existing in the vicinity of rotating dense bodies in the Universe, such as pulsars and magnetars. The observation of the scattered waves may reveal information about the twisted acoustic waves in the incoherent photon gas.
Electrodynamics of disk-accreting magnetic neutron stars
NASA Technical Reports Server (NTRS)
Miller, M. Coleman; Lamb, Frederick K.; Hamilton, Russell J.
1994-01-01
We have investigated the electrodynamics of magnetic neutron stars accreting from Keplerian disks and the implications for particle acceleration and gamma-ray emission by such systems. We argue that the particle density in the magnetospheres of such stars is larger by orders of magnitude than the Goldreich-Julian density, so that the formation of vacuum gaps is unlikely. We show that even if the star rotates slowly, electromotive forces (EMFs) of order 10(exp 15) V are produced by the interaction of plasma in the accretion disk with the magnetic field of the neutron star. The resistance of the disk-magnetosphere-star circuit is small, and hence these EMFs drive very large conduction currents. Such large currents are likely to produce magnetospheric instabilities, such as relativistic double layers and reconnection events, that can accelerate electrons or ions to very high energies.
Emergent electrodynamics from moving magnetic whirls in chiral magnets
NASA Astrophysics Data System (ADS)
Rosch, Achim
2012-02-01
In chiral magnets a lattice of magnetic whirls -- so-called skyrmions -- is stabilized in a small temperature and field range by thermal fluctuations [1]. We discuss how electric and spin currents couple to these skyrmions. As the spin of the electrons locally adjusts to the magnetic texture, the electron picks up a Berry phase. The effects of these time-dependent Berry phases are best described by ``artificial'' electric and magnetic fields of an emergent electrodynamics which couple to the spin and the spin currents. The efficient Berry phase coupling together with a partial cancellation of pinning forces due to the stiffness of the skyrmion lattice allows to explain theoretically experiments [2], which show that skyrmion lattices can be controlled by ultrasmall current densities. Using tiny gradients of temperature or magnetic field it is also possible to induce rotations of the skyrmion lattice. The topologically quantized winding number of the skyrmions induces exactly one quantum of emergent magnetic flux per skyrmion. Therefore one can also determine quantitatively the emergent electric field induced by a moving skyrmion following Faraday's law of induction as has been measured in recent experiments [3].[4pt] [1] Skyrmion Lattice in a Chiral Magnet, S. M"uhlbauer, B. Binz, F. Jonietz, C. Pfleiderer, A. Rosch, A. Neubauer, R. Georgii, P. B"oni, Science 323, 915 (2009). [0pt] [2] Spin Transfer Torques in MnSi at Ultralow Current Densities, F. Jonietz, S. M"hlbauer, C. Pfleiderer, A. Neubauer, W. M"unzer, A. Bauer, T. Adams, R. Georgii, P. B?ni, R. A. Duine, K. Everschor, M. Garst, and A. Rosch, Science 330, 1648 (2010).[0pt] [3] Emergent electrodynamics of skyrmions in a chiral magnet, T. Schulz, R. Ritz, A. Bauer, M. Halder, M. Wagner, C. Franz, and C. Pfleiderer, K. Everschor, M. Garst, and A. Rosch, preprint 2011.
The Momentum-eXchange/Electrodynamic Reboost (MXER) Tether Concept
NASA Astrophysics Data System (ADS)
Sorenson, K. F.
2004-12-01
Within NASA's In-Space Propulsion Technology Projects Office exists Emerging Propulsion Technologies (EPT) Investment Area that is advancing emerging propulsion concepts that have potential to lower the cost of space transportation, enable new missions, and/or increase the payload capability. The current, primary investment of EPT is the Momentum-eXchange/Electrodynamic Reboost (MXER) tether concept. The MXER tether is a long, rotating cable in an elliptical Earth orbit whose rapid rotation allows it to catch a payload in a low Earth orbit and throw it to a high-energy orbit. The orbital energy transferred by the MXER tether to the payload is restored to the tether via electrodynamic tether propulsion. This technique uses solar power to drive electrical current collected from the ionosphere through the tether, resulting in a magnetic interaction with the terrestrial field. Since the Earth itself serves as the reaction mass, the thrust force is generated without propellant, and allows the MXER facility to be repeatedly reused without resupply. Essentially, the MXER facility is a `propellantless' upper stage that could assist nearly every mission going beyond low Earth orbit. Payloads to interplanetary destinations would especially benefit from the boost provided by the MXER facility, resulting in launch vehicle cost reductions, increased payload fractions, and more frequent mission opportunities. Some of the benefits to space exploration include: (1) Multi-use, in-space, `propellantless' infrastructure, (2) Useable by essentially all missions beyond LEO, (3) Lowers overall mission costs and/or enables larger payloads, (4) ``Panama Canal" of space transportation, (5) A spiral development for future generations, (6) Readily scales up or down, (7) Future transportation to and from Lunar surface.
Studies of nonlinear electrodynamics of high-temperature superconductors
Lam, Quan-Chiu H.
1991-08-01
Nonlinear electrodynamics of high-{Tc} superconductors are studied both theoretically and experimentally. For powdered samples, a novel model is presented in which the metallographically observed superconducting grains in the powder are modeled as superconducting current loops of various areas with weak links. Surprising harmonic generation behavior in an arc field, H{sub 1} cos({omega}t), is predicted by the model; the power at high harmonics show sharp dips almost periodic in a superposing dc magnetic field, revealing flux quantization in the prototype loops in the model. Such oscillation of the harmonic power in dc magnetic field P{sub nf}(H{sub dc}), is indeed experimentally observed in powdered YBa{sub 2}Cu{sub 3}O{sub 7}. Other experimental aspects also agree with model predictions. For bulk sintered cylindrical samples, a generalized critical state model is presented. In this model, the nonlinear electrodynamics are due to flux-pinning, somewhat similar to low-temperature type-II superconductors, but with a more generalized critical current densities' dependence on magnetic field -- J{sub c}(H){approximately}H{sub local}{sup -{beta}}, with {beta} being an adjustable parameter. Experiments in ac and dc magnetic fields on a sintered cylindrical rod of YBa{sub 2}Cu{sub 3}O{sub 7} yield unambiguous evidence of independent inter- and intragranular contributions to the complex harmonic permeability {tilde {mu}}{sub n} = {mu}{prime}{sub n} -i{mu}{double prime}{sub n}. Temperature- dependence measurements reveal that, while the intragranular supercurrents disappear at {Tc}{ge}91.2 K, the intergranular supercurrents disappear at T{ge}86.6 K. This result is, to our knowledge, the first clear measurement of the phase-locking temperature of the 3-D matrix formed by YBa{sub 2}Cu{sub 3}O{sub 7} grains, which are in electrical contact with one another through weak links.
Studies of nonlinear electrodynamics of high-temperature superconductors
Lam, Quan-Chiu H.
1991-08-01
Nonlinear electrodynamics of high-{Tc} superconductors are studied both theoretically and experimentally. For powdered samples, a novel model is presented in which the metallographically observed superconducting grains in the powder are modeled as superconducting current loops of various areas with weak links. Surprising harmonic generation behavior in an arc field, H{sub 1} cos({omega}t), is predicted by the model; the power at high harmonics show sharp dips almost periodic in a superposing dc magnetic field, revealing flux quantization in the prototype loops in the model. Such oscillation of the harmonic power in dc magnetic field P{sub nf}(H{sub dc}), is indeed experimentally observed in powdered YBa{sub 2}Cu{sub 3}O{sub 7}. Other experimental aspects also agree with model predictions. For bulk sintered cylindrical samples, a generalized critical state model is presented. In this model, the nonlinear electrodynamics are due to flux-pinning, somewhat similar to low-temperature type-II superconductors, but with a more generalized critical current densities` dependence on magnetic field -- J{sub c}(H){approximately}H{sub local}{sup -{beta}}, with {beta} being an adjustable parameter. Experiments in ac and dc magnetic fields on a sintered cylindrical rod of YBa{sub 2}Cu{sub 3}O{sub 7} yield unambiguous evidence of independent inter- and intragranular contributions to the complex harmonic permeability {tilde {mu}}{sub n} = {mu}{prime}{sub n} -i{mu}{double_prime}{sub n}. Temperature- dependence measurements reveal that, while the intragranular supercurrents disappear at {Tc}{ge}91.2 K, the intergranular supercurrents disappear at T{ge}86.6 K. This result is, to our knowledge, the first clear measurement of the phase-locking temperature of the 3-D matrix formed by YBa{sub 2}Cu{sub 3}O{sub 7} grains, which are in electrical contact with one another through weak links.
Probing nonlinear electrodynamics in slowly rotating spacetimes through neutrino astrophysics
NASA Astrophysics Data System (ADS)
Mosquera Cuesta, Herman J.; Lambiase, Gaetano; Pereira, Jonas P.
2017-01-01
Huge electromagnetic fields are known to be present during the late stages of the dynamics of supernovae. Thus, when dealing with electrodynamics in this context, the possibility may arise to probe nonlinear theories (generalizations of the Maxwellian electromagnetism). We firstly solve Einstein field equations minimally coupled to an arbitrary (current-free) nonlinear Lagrangian of electrodynamics (NLED) in the slow rotation regime a ≪M (black hole's mass), up to first order in a /M . We then make use of the robust and self-contained Born-Infeld Lagrangian in order to compare and contrast the physical properties of such NLED spacetime with its Maxwellian counterpart (a slowly rotating Kerr-Newman spacetime), especially focusing on the astrophysics of both neutrino flavor oscillations (νe→νμ , ντ ) and spin-flip (νl→νr, "l " stands for "left" and "r " stands for "right", change of neutrino handedness) mass level crossings, the equivalent to gyroscopic precessions. Such analysis proves that in the spacetime of a slowly rotating nonlinear charged black hole (RNCBH), intrinsically associated with the assumption the electromagnetism is nonlinear, the neutrino dynamics in core-collapse supernovae could be significantly changed. In such an astrophysical environment, a positive enhancement (reduction of the electron fraction Ye<0.5 ) of the r-process may take place. Consequently, it might result in hyperluminous supernova explosions due to enlargement, in atomic number and amount, of the decaying nuclides. Finally, we envisage some physical scenarios that may lead to short-lived charged black holes with high charge-to-mass ratios (associated with unstable highly magnetized neutron stars) and ways to possibly disentangle theories of the electromagnetism from other black hole observables (by means of light polarization measurements).
The PROPEL Electrodynamic Tether Mission and Connecting to the Ionosphere
NASA Technical Reports Server (NTRS)
Gilchrist, Brian; Bilen, Sven; Hoyt, Rob; Stone,Nobie; Vaughn, Jason; Fuhrhop, Keith; Krause, Linda; Khazanov, George; Johnson, Les
2012-01-01
The exponential increase of launch system size.and cost.with delta-V makes missions that require large total impulse cost prohibitive. Led by NASA's Marshall Space Flight Center, a team from government, industry, and academia has developed a flight demonstration mission concept of an integrated electrodynamic (ED) tethered satellite system called PROPEL: "Propulsion using Electrodynamics". The PROPEL Mission is focused on demonstrating a versatile configuration of an ED tether to overcome the limitations of the rocket equation, enable new classes of missions currently unaffordable or infeasible, and significantly advance the Technology Readiness Level (TRL) to an operational level. We are also focused on establishing a far deeper understanding of critical processes and technologies to be able to scale and improve tether systems in the future. Here, we provide an overview of the proposed PROPEL mission. One of the critical processes for efficient ED tether operation is the ability to inject current to and collect current from the ionosphere. Because the PROPEL mission is planned to have both boost and deboost capability using a single tether, the tether current must be capable of flowing in both directions and at levels well over 1 A. Given the greater mobility of electrons over that of ions, this generally requires that both ends of the ED tether system can both collect and emit electrons. For example, hollow cathode plasma contactors (HCPCs) generally are viewed as state-of-the-art and high TRL devices; however, for ED tether applications important questions remain of how efficiently they can operate as both electron collectors and emitters. Other technologies will be highlighted that are being investigated as possible alternatives to the HCPC such as Solex that generates a plasma cloud from a solid material (Teflon) and electron emission (only) technologies such as cold-cathode electron field emission or photo-electron beam generation (PEBG) techniques.
NASA Astrophysics Data System (ADS)
Kholmetskii, A. L.; Missevitch, O. V.; Yarman, T.
2016-09-01
We consider the relativistic transformation of the magnetic dipole moment and disclose its physical meaning, shedding light on the related difficulties in the physical interpretation of classical electrodynamics in material media.
NASA Astrophysics Data System (ADS)
Gulyaev, Yurii V.; Kravchenko, Viktor F.; Kuraev, Aleksandr A.
2004-06-01
Optimal control theory-based methods for improving the efficiency of Cherenkov microwave amplifiers with irregular electrodynamic structures are reviewed. The physics of optimal processes in amplifiers and oscillators with Cherenkov- and combined-type interactions is discussed.
NASA Technical Reports Server (NTRS)
Stekly, Z. J. J.; Gardner, C.; Domigan, P.; Baker, J.; Hass, M.; McDonald, C.; Wu, C.; Farrell, R. A.
1996-01-01
Two 214.5 cm. long high performance periodic (26 cm period) permanent magnet half-assemblies were designed and constructed for use as a wiggler using Nd-B-Fe and vanadium permendur as hard and soft magnetic materials by Field Effects, a division of Intermagnetics General Corporation. Placing these assemblies in a supporting structure with a 2.1 cm pole to pole separation resulted in a periodic field with a maximum value of 2.04 T. This is believed to be the highest field ever achieved by this type of device. The attractive force between the two 602 kg magnet assemblies is 228 kN, providing enough force for suspension of a 45,500 kg vehicle. If used in an attractive maglev system with an appropriate flat iron rail, one assembly will generate the same force with a gap of 1.05 cm leading to a lift to weight ratio of 38.6, not including the vehicle attachment structure. This permanent magnet compares well with superconducting systems which have lift to weight ratios in the range of 5 to 10. This paper describes the magnet assemblies and their measured magnetic performance. The measured magnetic field and resulting attractive magnetic force have a negative spring characteristic. Appropriate control coils are necessary to provide stable operation. The estimated performance of the assemblies in a stable repulsive mode, with eddy currents in a conducting guideway, is also discussed.
NASA Technical Reports Server (NTRS)
1979-01-01
The middle atmosphere (MA), which is defined as the region bounded below by the tropopause near 10 km and above by the mesopause near 90 to 100 km, is regarded as a passive medium through which electric fields and currents are transmitted from sources above and below. A scientific background is given for: sources of MA electric fields; MA conductivity and currents; and MA plasma characteristics. Recommendations are given for research in MA electrodynamics in the following areas: (1) MA electrodynamical parameters; (2) models and supportive laboratory measurements; and (3) investigation of specific problems in the coupled systems.
Electrodynamic parameters in the nighttime sector during auroral substorms
NASA Technical Reports Server (NTRS)
Fujii, R.; Hoffman, R. A.; Anderson, P. C.; Craven, J. D.; Sugiura, M.; Frank, L. A.; Maynard, N. C.
1994-01-01
The characteristics of the large-scale electrodynamic parameters, field-aligned currents (FACs), electric fields, and electron precipitation, which are associated with auroral substorm events in the nighttime sector, have been obtained through a unique analysis which places the ionospheric measurements of these parameters into the context of a generic substorm determined from global auroral images. A generic bulge-type auroral emission region has been deduced from auroral images taken by the Dynamics Explorer 1 (DE 1) satellite during a number of isolated substorms, and the form has been divided into six sectors, based on the peculiar emission characteristics in each sector: west of bulge, surge horn, surge, middle surge, eastern bulge, and east of bulge. By comparing the location of passes of the Dynamics Explorer 2 (DE 2) satellite to the simultaneously obtained auroral images, each pass is placed onto the generic aurora. The organization of DE 2 data in this way has systematically clarified peculiar characteristics in the electrodynamic parameters. An upward net current mainly appears in the surge, with little net current in the surge horn and the west of bulge. The downward net current is distributed over wide longitudinal regions from the eastern bulge to the east of bulge. Near the poleward boundary of the expanding auroral bulge, a pair of oppositely directed FAC sheets is observed, with the downward FAC on the poleward side. This downward FAC and most of the upward FAC in the surge and the middle surge are assoc iated with narrow, intense antisunwqard convection, corresponding to an equatorward directed spikelike electric field. This pair of currents decreases in amplitude and latitudinal width toward dusk in the surge and the west of bulge, and the region 1 and 2 FACs become embedded in the sunward convection region. The upward FAC region associated with the spikelike field on the poleward edge of the bulge coincides well with intense electron
Longitudinal Differences of Ionospheric Vertical Density Distribution and Equatorial Electrodynamics
NASA Technical Reports Server (NTRS)
Yizengaw, E.; Zesta, E.; Moldwin, M. B.; Damtie, B.; Mebrahtu, A.; Valledares, C.E.; Pfaff, R. F.
2012-01-01
Accurate estimation of global vertical distribution of ionospheric and plasmaspheric density as a function of local time, season, and magnetic activity is required to improve the operation of space-based navigation and communication systems. The vertical density distribution, especially at low and equatorial latitudes, is governed by the equatorial electrodynamics that produces a vertical driving force. The vertical structure of the equatorial density distribution can be observed by using tomographic reconstruction techniques on ground-based global positioning system (GPS) total electron content (TEC). Similarly, the vertical drift, which is one of the driving mechanisms that govern equatorial electrodynamics and strongly affect the structure and dynamics of the ionosphere in the low/midlatitude region, can be estimated using ground magnetometer observations. We present tomographically reconstructed density distribution and the corresponding vertical drifts at two different longitudes: the East African and west South American sectors. Chains of GPS stations in the east African and west South American longitudinal sectors, covering the equatorial anomaly region of meridian approx. 37 deg and 290 deg E, respectively, are used to reconstruct the vertical density distribution. Similarly, magnetometer sites of African Meridian B-field Education and Research (AMBER) and INTERMAGNET for the east African sector and South American Meridional B-field Array (SAMBA) and Low Latitude Ionospheric Sensor Network (LISN) are used to estimate the vertical drift velocity at two distinct longitudes. The comparison between the reconstructed and Jicamarca Incoherent Scatter Radar (ISR) measured density profiles shows excellent agreement, demonstrating the usefulness of tomographic reconstruction technique in providing the vertical density distribution at different longitudes. Similarly, the comparison between magnetometer estimated vertical drift and other independent drift observation
Implementing phase-covariant cloning in circuit quantum electrodynamics
NASA Astrophysics Data System (ADS)
Zhu, Meng-Zheng; Ye, Liu
2016-10-01
An efficient scheme is proposed to implement phase-covariant quantum cloning by using a superconducting transmon qubit coupled to a microwave cavity resonator in the strong dispersive limit of circuit quantum electrodynamics (QED). By solving the master equation numerically, we plot the Wigner function and Poisson distribution of the cavity mode after each operation in the cloning transformation sequence according to two logic circuits proposed. The visualizations of the quasi-probability distribution in phase-space for the cavity mode and the occupation probability distribution in the Fock basis enable us to penetrate the evolution process of cavity mode during the phase-covariant cloning (PCC) transformation. With the help of numerical simulation method, we find out that the present cloning machine is not the isotropic model because its output fidelity depends on the polar angle and the azimuthal angle of the initial input state on the Bloch sphere. The fidelity for the actual output clone of the present scheme is slightly smaller than one in the theoretical case. The simulation results are consistent with the theoretical ones. This further corroborates our scheme based on circuit QED can implement efficiently PCC transformation.
The electrodynamics of aerosols and bacteria in a microplasma
NASA Astrophysics Data System (ADS)
Maguire, P. D.; Mahony, C. M. O.; Diver, D.; Mariotti, D.; Bennet, E.; Potts, H.; McDowell, D. A.
2013-09-01
The physics of living organisms is considered a grand challenge of science. Plasma interactions with living organisms, particularly at atmospheric pressure, offer a unique opportunity to study the physical mechanisms and surface electrodynamics of individual microorganisms. The impact on the plasma of such macroscopic entities is itself important; the dynamics of non-spherical and non-rigid nano-/micro-scale structures have received little attention. Also the plasma interaction with water, from molecules to droplets, is becoming increasingly significant due to induced chemistries that differ considerably from conventional plasma chemistry. We investigate the bulk and surface physical properties of individual microorganisms, particularly bacteria, through electrical and visco-mechanical excitation. Individual organisms are transported by water droplets to an rf microplasma. Their impact on the plasma is determined by imaging, optical and electrical diagnostics. We report, using imaging, electrostatics and simulation, on (i) fluid stability under evaporative stress of charged microbe-carrying macroscopic droplets, (ii) impact of the plasma on the stochastic component of motion and (iii) the acquired charge distribution and transfer from liquid to lipid surface. Engineering and Physical Sciences Research Council EP/K006088, EP/K006142.
Acoustic characteristics of an electrodynamic planar digital loudspeaker.
Furihata, Kenji; Hayama, Atsushi; Asano, David K; Yanagisawa, Takesaburo
2003-07-01
In this paper, an electrodynamic planar loudspeaker driven by a digital signal is experimentally discussed. The digital loudspeaker consists of 22 voice coils, 11 permanent magnets, a diaphragm with streamlined sections molded in plastic, and a suspension made of handmade Japanese paper between the diaphragm and the frame. First, the acoustic responses are affected by the arrangement of the voice coils, so an asymmetric arrangement is studied. This asymmetric arrangement is designed to obtain as flat a frequency response to an analog signal as possible. This arrangement is compared with a symmetric one and results show that the flatness of the frequency response around 1 kHz and 4 kHz is improved and that the sound reproduction band is from 40 Hz to 10 kHz. Second, to evaluate the acoustic responses to a digital signal, the digital loudspeaker is driven with a pulse code modulation signal. Results show that the digital loudspeaker can reproduce pure sound with a total harmonic distortion of less than 5% from 40 Hz to 10 kHz, exceeding this value only in a narrow frequency band near 4 kHz. This digital loudspeaker was demonstrated to have good linearity over its dynamic range of 84 dB.
Orbit Optimization for the Geospace Electrodynamics Connections (GEC) Mission
NASA Technical Reports Server (NTRS)
Mesarch, Michael A.
2003-01-01
The Geospace Electrodynamics Connections (GEC) mission plan is to launch multiple spacecraft to perform in-situ atmospheric science in the lower ionosphere. There is limited experience in this low altitude region with the Atmospheric Explorer-C (AE-C) being the last spacecraft to explore this region in 1973. AE-C flew an eccentric orbit using maneuvers to lower its perigee to near 130 km at various times during its mission. GEC will advance the science performed by AE-C by performing multiple low-perigee, atmospheric dipping campaigns for extended durations. AE-C kept its perigee near 130 km for only a total of roughly 1 day. Furthermore, GEC plans to carry a more diverse suite of instruments and will be able to capture different temporal and spatial phenomena through the use of multiple spacecraft flying in a string of pearls formation. The mission analysis for GEC has been broken into two parts: the analysis of the parking orbit with the dipping campaigns and the examination of the multi-satellite dynamics of the GEC constellation. The analysis described in this paper examines the capability to meet the requirements necessary to support the 10 dipping campaigns using a single spacecraft as a representative of all three in the constellation. Further analysis is being performed to analyze the multi-satellite nature of the GEC mission.
Modeling and study of nonlinear effects in electrodynamic shakers
NASA Astrophysics Data System (ADS)
Saraswat, Abhishek; Tiwari, Nachiketa
2017-02-01
An electrodynamic shaker is inherently a nonlinear electro-mechanical system. In this work, we have developed a lumped parameter model for the entire electromechanical system, developed an approach to non-destructively determine these parameters, and predict the nonlinear response of the shaker. This predicted response has been validated using experimental data. Through such an approach, we have been able to accurately predict the resulting distortions in the response of the shaker and other nonlinear effects like DC offset in the displacement response. Our approach offers a key advantage vis-à-vis other approaches which rely on techniques involving Volterra Series expansions or techniques based on blackbox models like neural networks, which is that in our approach, apart from predicting the response of the shaker, the model parameters obtained have a physical significance and changes in the parameters can be directly mapped to modification in key design parameters of the shaker. The proposed approach is also advantageous in one more way: it requires measurement of only four parameters, voltage, current, displacement and acceleration for estimating shaker model parameters non-destructively. The proposed model can be used for the design of linearization controllers, prototype testing and simulation of new shaker designs as well as for performance prediction of shakers under testing conditions.
Thermodynamics of charged black holes with a nonlinear electrodynamics source
Gonzalez, Hernan A.; Hassaiene, Mokhtar; Martinez, Cristian
2009-11-15
We study the thermodynamical properties of electrically charged black hole solutions of a nonlinear electrodynamics theory defined by a power p of the Maxwell invariant, which is coupled to Einstein gravity in four and higher spacetime dimensions. Depending on the range of the parameter p, these solutions present different asymptotic behaviors. We compute the Euclidean action with the appropriate boundary term in the grand canonical ensemble. The thermodynamical quantities are identified and, in particular, the mass and the charge are shown to be finite for all classes of solutions. Interestingly, a generalized Smarr formula is derived and it is shown that this latter encodes perfectly the different asymptotic behaviors of the black hole solutions. The local stability is analyzed by computing the heat capacity and the electrical permittivity and we find that a set of small black holes is locally stable. In contrast to the standard Reissner-Nordstroem solution, there is a first-order phase transition between a class of these nonlinear charged black holes and the Minkowski spacetime.
The Kummer tensor density in electrodynamics and in gravity
Baekler, Peter; Favaro, Alberto; Itin, Yakov; Hehl, Friedrich W.
2014-10-15
Guided by results in the premetric electrodynamics of local and linear media, we introduce on 4-dimensional spacetime the new abstract notion of a Kummer tensor density of rank four, K{sup ijkl}. This tensor density is, by definition, a cubic algebraic functional of a tensor density of rank four T{sup ijkl}, which is antisymmetric in its first two and its last two indices: T{sup ijkl}=−T{sup jikl}=−T{sup ijlk}. Thus, K∼T{sup 3}, see Eq. (46). (i) If T is identified with the electromagnetic response tensor of local and linear media, the Kummer tensor density encompasses the generalized Fresnel wave surfaces for propagating light. In the reversible case, the wave surfaces turn out to be Kummer surfaces as defined in algebraic geometry (Bateman 1910). (ii) If T is identified with the curvature tensor R{sup ijkl} of a Riemann–Cartan spacetime, then K∼R{sup 3} and, in the special case of general relativity, K reduces to the Kummer tensor of Zund (1969). This K is related to the principal null directions of the curvature. We discuss the properties of the general Kummer tensor density. In particular, we decompose K irreducibly under the 4-dimensional linear group GL(4,R) and, subsequently, under the Lorentz group SO(1,3)
On the initial value formulation of classical electrodynamics
NASA Astrophysics Data System (ADS)
Deckert, Dirk-André; Hartenstein, Vera
2016-11-01
We describe a seemingly un-noticed feature of the text-book Maxwell-Lorentz system of classical electrodynamics which challenges its formulation in terms of an initial value problem. For point-charges, even after appropriate renormalization, we demonstrate that most of the generic initial data evolves to develop singularities in the electromagnetic fields along the light cones of the initial charge positions. We provide explicit formulas for the corresponding fields, demonstrate how this phenomenon renders the initial value problem ill-posed, and show how such bad initial data can be ruled out by extra conditions in addition to the Maxwell constraints. These extra conditions, however, require knowledge of the history of the solution and, as we discuss, effectively turn the Maxwell-Lorentz system into a system of delay equations much like the Fokker-Schwarzschild-Tetrode equations. For extended charges such singular light fronts persist in a smoothened form and, as we argue, yield physically doubtful solutions. Our results also apply to some extent to expectation values of field operators in quantum field theory.
Nonlinear electrodynamics and thermodynamic geometry of rotating dilaton black branes
NASA Astrophysics Data System (ADS)
Sheykhi, A.; Naeimipour, F.; Zebarjad, S. M.
2016-07-01
We construct a new class of rotating dilaton solutions in the presence of logarithmic nonlinear electrodynamics. These solutions represent black branes with flat horizon and contain k=[(n-1)/2] rotation parameters in n-dimensional spacetime where [ x] is the integer part of x. We study the causal structure of the spacetime and calculate thermodynamic and conserved quantities and show that these quantities satisfy the first law of thermodynamics on the black brane horizon, { dM}={ TdS}+{{{sum _{i=1}k}}}Ω id{J}i+{ Ud}{Q}. Then, we study geometrical approach towards thermodynamics by choosing an appropriate geometrical metric. We show that the singularity of the Ricci scalar coincides exactly with the phase transition points. We observe that our system encounters two types of phase transitions depending on the metric parameters. For the first one the heat capacity is zero and for the second one the heat capacity diverges. In the first kind of phase transition, the brane has a transition from an unstable non-physical to a stable physical state. In the second type of phase transition the brane moves from a stable to an unstable state. Finally, we comment on the dynamical stability of the obtained solutions under perturbations in four dimensions.
Thermodynamics of charged black holes with a nonlinear electrodynamics source
NASA Astrophysics Data System (ADS)
González, Hernán A.; Hassaïne, Mokhtar; Martínez, Cristián
2009-11-01
We study the thermodynamical properties of electrically charged black hole solutions of a nonlinear electrodynamics theory defined by a power p of the Maxwell invariant, which is coupled to Einstein gravity in four and higher spacetime dimensions. Depending on the range of the parameter p, these solutions present different asymptotic behaviors. We compute the Euclidean action with the appropriate boundary term in the grand canonical ensemble. The thermodynamical quantities are identified and, in particular, the mass and the charge are shown to be finite for all classes of solutions. Interestingly, a generalized Smarr formula is derived and it is shown that this latter encodes perfectly the different asymptotic behaviors of the black hole solutions. The local stability is analyzed by computing the heat capacity and the electrical permittivity and we find that a set of small black holes is locally stable. In contrast to the standard Reissner-Nordström solution, there is a first-order phase transition between a class of these nonlinear charged black holes and the Minkowski spacetime.
Electrodynamic structure of the morning high-latitude trough region
NASA Astrophysics Data System (ADS)
Vanhamäki, H.; Aikio, A.; Voiculescu, M.; Juusola, L.; Nygrén, T.; Kuula, R.
2016-03-01
We describe the electrodynamics of a postmidnight, high-latitude ionospheric trough, observed with the European Incoherent Scatter radar in northern Scandinavia on 24-25 June 2003 around 22:00-02:30 UT during quiet conditions. The UHF radar made meridian scans with a 30 min cadence resulting in nine cross sections of ionospheric parameters. The F region electric field was also determined with the tristatic system. Ionospheric equivalent currents, calculated from ground magnetometer data, mostly show an electrojet-like current that is reasonably uniform in the longitudinal direction. Combined analysis of the conductances and equivalent current with a local Kamide-Richmond-Matsushita (KRM) method yields the ionospheric electric field and field-aligned current (FAC) in a 2-D (latitude-longitude) area around the radar. We conclude that the most likely scenario is one where the trough is initially created poleward of the auroral oval by downward FAC that evacuates the F region, but as the trough moves to lower latitudes during the early morning hours, it becomes colocated with the westward electrojet. There the electron density further decreases due to increased recombination caused by enhanced ion temperature, which in turn is brought about by a larger convection speed. Later in the morning the convection speed decreases and the trough is filled by increasing photoionization.
Interference control of perfect photon absorption in cavity quantum electrodynamics
NASA Astrophysics Data System (ADS)
Wang, Liyong; Di, Ke; Zhu, Yifu; Agarwal, G. S.
2017-01-01
We propose and analyze a scheme for controlling coherent photon transmission and reflection in a cavity-quantum-electrodynamics (CQED) system consisting of an optical resonator coupled with three-level atoms coherently prepared by a control laser from free space. When the control laser is off and the cavity is excited by two identical light fields from two ends of the cavity, the two input light fields can be completely absorbed by the CQED system and the light energy is converted into the excitation of the polariton states, but no light can escape from the cavity. Two distinct cases of controlling the perfect photon absorption are analyzed: (a) when the control laser is tuned to the atomic resonance and creates electromagnetically induced transparency, the perfect photon absorption is suppressed and the input light fields are nearly completely transmitted through the cavity; (b) when the control laser is tuned to the polariton state resonance and inhibits the polariton state excitation, the perfect photon absorption is again suppressed and the input light fields are nearly completely reflected from the cavity. Thus, the CQED system can act as a perfect absorber or near-perfect transmitter and/or reflector by simply turning the control laser off or on. Such interference control of the coherent photon-atom interaction in the CQED system should be useful for a variety of applications in optical logical devices.
Third emission mechanism in solid-state nanocavity quantum electrodynamics.
Yamaguchi, Makoto; Asano, Takashi; Noda, Susumu
2012-09-01
Photonic crystal (PC) nanocavities have been receiving a great deal of attention recently because of their ability to strongly confine photons in a tiny space with a high quality factor. According to cavity quantum electrodynamics (cavity QED), such confined photons can achieve efficient interactions with excitons in semiconductors, leading to the Purcell effect in the weak coupling regime and vacuum Rabi splitting (VRS) in the strong coupling regime. These features are promising for applications such as quantum information processing, highly efficient single photon sources and ultra-low threshold lasers. In this context, the coupled system of a semiconductor quantum dot (QD) and a PC nanocavity has been intensively investigated in recent years.Although experimental reports have demonstrated such fundamental features, two anomalous phenomena have also been observed. First, photon emission from the cavity occurs even when it is significantly detuned from the QD. Second, spectral triplets are formed by additional bare-cavity lines between the VRS lines. These features cannot be explained by standard cavity QED theories and have prompted controversy regarding their physical mechanisms. In this review we describe the recent experimental and theoretical progress made in the investigation of these phenomena. Similar mechanisms will also occur in many other coupled quantum systems, and thus the findings are applicable to a wide range of fields.
Quantum Electrodynamics in d=3 from the ε Expansion.
Di Pietro, Lorenzo; Komargodski, Zohar; Shamir, Itamar; Stamou, Emmanuel
2016-04-01
We study quantum electrodynamics in d=3 coupled to N_{f} flavors of fermions. The theory flows to an IR fixed point for N_{f} larger than some critical number N_{f}^{c}. For N_{f}≤N_{f}^{c}, chiral-symmetry breaking is believed to take place. In analogy with the Wilson-Fisher description of the critical O(N) models in d=3, we make use of the existence of a fixed point in d=4-2ε to study the three-dimensional conformal theory. We compute, in perturbation theory, the IR dimensions of fermion bilinear and quadrilinear operators. For small N_{f}, a quadrilinear operator can become relevant in the IR and destabilize the fixed point. Therefore, the epsilon expansion can be used to estimate N_{f}^{c}. An interesting novelty compared to the O(N) models is that the theory in d=3 has an enhanced symmetry due to the structure of 3D spinors. We identify the operators in d=4-2ε that correspond to the additional conserved currents at d=3 and compute their infrared dimensions.
The Kummer tensor density in electrodynamics and in gravity
NASA Astrophysics Data System (ADS)
Baekler, Peter; Favaro, Alberto; Itin, Yakov; Hehl, Friedrich W.
2014-10-01
Guided by results in the premetric electrodynamics of local and linear media, we introduce on 4-dimensional spacetime the new abstract notion of a Kummer tensor density of rank four, K. This tensor density is, by definition, a cubic algebraic functional of a tensor density of rank four T, which is antisymmetric in its first two and its last two indices: T=-T=-T. Thus, K∼T3, see Eq. (46). (i) If T is identified with the electromagnetic response tensor of local and linear media, the Kummer tensor density encompasses the generalized Fresnel wave surfaces for propagating light. In the reversible case, the wave surfaces turn out to be Kummer surfaces as defined in algebraic geometry (Bateman 1910). (ii) If T is identified with the curvature tensor R of a Riemann-Cartan spacetime, then K∼R3 and, in the special case of general relativity, K reduces to the Kummer tensor of Zund (1969). This K is related to the principal null directions of the curvature. We discuss the properties of the general Kummer tensor density. In particular, we decompose K irreducibly under the 4-dimensional linear group GL(4,R) and, subsequently, under the Lorentz group SO(1,3).
Electrodynamical Model of Quasi-Efficient Financial Markets
NASA Astrophysics Data System (ADS)
Ilinski, Kirill N.; Stepanenko, Alexander S.
The modelling of financial markets presents a problem which is both theoretically challenging and practically important. The theoretical aspects concern the issue of market efficiency which may even have political implications [1], whilst the practical side of the problem has clear relevance to portfolio management [2] and derivative pricing [3]. Up till now all market models contain "smart money" traders and "noise" traders whose joint activity constitutes the market [4, 5]. On a short time scale this traditional separation does not seem to be realistic, and is hardly acceptable since all high-frequency market participants are professional traders and cannot be separated into "smart" and "noisy." In this paper we present a "microscopic" model with homogenuous quasi-rational behaviour of traders, aiming to describe short time market behaviour. To construct the model we use an analogy between "screening" in quantum electrodynamics and an equilibration process in a market with temporal mispricing [6, 7]. As a result, we obtain the time-dependent distribution function of the returns which is in quantitative agreement with real market data and obeys the anomalous scaling relations recently reported for both high-frequency exchange rates [8], S&P500 [9] and other stock market indices [10, 11].
Cavity State Reservoir Engineering in Circuit Quantum Electrodynamics
NASA Astrophysics Data System (ADS)
Holland, Eric T.
Engineered quantum systems are poised to revolutionize information science in the near future. A persistent challenge in applied quantum technology is creating controllable, quantum interactions while preventing information loss to the environment, decoherence. In this thesis, we realize mesoscopic superconducting circuits whose macroscopic collective degrees of freedom, such as voltages and currents, behave quantum mechanically. We couple these mesoscopic devices to microwave cavities forming a cavity quantum electrodynamics (QED) architecture comprised entirely of circuit elements. This application of cavity QED is dubbed Circuit QED and is an interdisciplinary field seated at the intersection of electrical engineering, superconductivity, quantum optics, and quantum information science. Two popular methods for taming active quantum systems in the presence of decoherence are discrete feedback conditioned on an ancillary system or quantum reservoir engineering. Quantum reservoir engineering maintains a desired subset of a Hilbert space through a combination of drives and designed entropy evacuation. Circuit QED provides a favorable platform for investigating quantum reservoir engineering proposals. A major advancement of this thesis is the development of a quantum reservoir engineering protocol which maintains the quantum state of a microwave cavity in the presence of decoherence. This thesis synthesizes strongly coupled, coherent devices whose solutions to its driven, dissipative Hamiltonian are predicted a priori. This work lays the foundation for future advancements in cavity centered quantum reservoir engineering protocols realizing hardware efficient circuit QED designs.
Ultrafast terahertz electrodynamics of photonic and electronic nanostructures
Luo, Liang
2015-01-01
This thesis summarizes my work on using ultrafast laser pulses to study Terahertz (THz) electrodynamics of photonic and electronic nanostructures and microstructures. Ultrafast timeresolved (optical, NIR, MIR, THz) pump-probe spectroscopy setup has been successfully built, which enables me to perform a series of relevant experiments. Firstly, a novel high e ciency and compact THz wave emitter based on split-ring-resonators has been developed and characterized. The emitter can be pumped at any wavelength by tailoring the magnetic resonance and could generate gapless THz waves covering the entire THz band. Secondly, two kinds of new photonic structures for THz wave manipulation have been successfully designed and characterized. One is based on the 1D and 2D photo-imprinted di ractive elements. The other is based on the photoexcited double-split-ring-resonator metamaterials. Both structures are exible and can modulate THz waves with large tunability. Thirdly, the dark excitons in semiconducting singlewalled carbon nanotubes are studied by optical pump and THz probe spectroscopy, which provides the rst insights into the THz responses of nonequilibrium excitonic correlations and dynamics from the dark ground states in carbon nanotubes. Next, several on-going projects are brie y presented such as the study of ultrafast THz dynamics of Dirac fermions in topological insulator Bi_{2}Se_{3} with Mid-infrared excitation. Finally, the thesis ends with a summary of the completed experiments and an outlook of the future plan.
Three-dimensional lattice Boltzmann model for electrodynamics.
Mendoza, M; Muñoz, J D
2010-11-01
In this paper we introduce a three-dimensional Lattice-Boltzmann model that recovers in the continuous limit the Maxwell equations in materials. In order to build conservation equations with antisymmetric tensors, like the Faraday law, the model assigns four auxiliary vectors to each velocity vector. These auxiliary vectors, when combined with the distribution functions, give the electromagnetic fields. The evolution is driven by the usual Bhatnager-Gross-Krook (BGK) collision rule, but with a different form for the equilibrium distribution functions. This lattice Bhatnager-Gross-Krook (LBGK) model allows us to consider for both dielectrics and conductors with realistic parameters, and therefore it is adequate to simulate the most diverse electromagnetic problems, like the propagation of electromagnetic waves (both in dielectric media and in waveguides), the skin effect, the radiation pattern of a small dipole antenna and the natural frequencies of a resonant cavity, all with 2% accuracy. Actually, it shows to be one order of magnitude faster than the original Finite-difference time-domain (FDTD) formulation by Yee to reach the same accuracy. It is, therefore, a valuable alternative to simulate electromagnetic fields and opens lattice Boltzmann for a broad spectrum of new applications in electrodynamics.
Electron-photon coupling in mesoscopic quantum electrodynamics
NASA Astrophysics Data System (ADS)
Cottet, A.; Kontos, T.; Douçot, B.
2015-05-01
Understanding the interaction between cavity photons and electronic nanocircuits is crucial for the development of mesoscopic quantum electrodynamics (QED). One has to combine ingredients from atomic cavity QED, such as orbital degrees of freedom, with tunneling physics and strong cavity field inhomogeneities, specific to superconducting circuit QED. It is therefore necessary to introduce a formalism which bridges between these two domains. We develop a general method based on a photonic pseudopotential to describe the electric coupling between electrons in a nanocircuit and cavity photons. In this picture, photons can induce simultaneously orbital energy shifts, tunneling, and local orbital transitions. We study in detail the elementary example of a single quantum dot with a single normal metal reservoir, coupled to a cavity. Photon-induced tunneling terms lead to a nonuniversal relation between the cavity frequency pull and the damping pull. Our formalism can also be applied to multiple quantum dot circuits, molecular circuits, quantum point contacts, metallic tunnel junctions, and superconducting nanostructures enclosing Andreev bound states or Majorana bound states, for instance.
Quantum electrodynamic approach to the conductivity of gapped graphene
NASA Astrophysics Data System (ADS)
Klimchitskaya, G. L.; Mostepanenko, V. M.
2016-11-01
The electrical conductivity of graphene with a nonzero mass-gap parameter is investigated starting from the first principles of quantum electrodynamics in (2+1)-dimensional space time at any temperature. The formalism of the polarization tensor defined over the entire plane of complex frequency is used. At zero temperature we reproduce the results for both real and imaginary parts of the conductivity, obtained previously in the local approximation, and generalize them taking into account the effects of nonlocality. At nonzero temperature the exact analytic expressions for real and imaginary parts of the longitudinal and transverse conductivities of gapped graphene are derived, as well as their local limits and approximate expressions in several asymptotic regimes. Specifically, a simple local result for the real part of conductivity of gapped graphene valid at any temperature is obtained. According to our results, the real part of the conductivity is not equal to zero for frequencies exceeding the width of the gap and goes to the universal conductivity with increasing frequency. The imaginary part of conductivity of gapped graphene varies from infinity at zero frequency to minus infinity at the frequency defined by the gap parameter and then goes to zero with further increase of frequency. The analytic expressions are accompanied by the results of numerical computations. Possible future generalization of the used formalism is discussed.
Voyager 2 encounter with Ganymede's wake: hydromagnetic and electrodynamic processes
Tariq, G.F.
1984-01-01
Voyager 2's passage through corotation wake region of Ganymede found disturbances in the energetic particle and magnetic field data. To explain the nature of disturbances, an investigation of the interaction of the Jovian plasma with Ganymede is carried out. A series of computer simulations, supported by appropriate theories, are made. Three different aspects of the interaction are studied: (i) A magnetic field model is proposed to describe Alfvenic disturbances caused by Ganymede. Numerical simulations show that the interaction of ensembles of ions with perturbed fields modulates the energies of the ions. The amount of modulation depends on the Alfven mach number of the ambient plasma, the ion energy, and the pitch angle of the ions. (ii) The electrodynamic processes associated with the plasma-Ganymede interaction and the plasma expansion into the cavity are simulated using a particle-in-cell method. The distribution of ions, potentials, ion and electron thermal and drift energies in the wake region are obtained. (iii) Using linear MHD theory, conditions for excitation and growth of the Kelvin-Helmholtz instability are investigated. Theoretical conditions for the existence of magnetosonic waves and transverse Alfven waves are also examined.
Internally electrodynamic particle model: Its experimental basis and its predictions
Zheng-Johansson, J. X.
2010-03-15
The internally electrodynamic (IED) particle model was derived based on overall experimental observations, with the IED process itself being built directly on three experimental facts: (a) electric charges present with all material particles, (b) an accelerated charge generates electromagnetic waves according to Maxwell's equations and Planck energy equation, and (c) source motion produces Doppler effect. A set of well-known basic particle equations and properties become predictable based on first principles solutions for the IED process; several key solutions achieved are outlined, including the de Broglie phase wave, de Broglie relations, Schroedinger equation, mass, Einstein mass-energy relation, Newton's law of gravity, single particle self interference, and electromagnetic radiation and absorption; these equations and properties have long been broadly experimentally validated or demonstrated. A conditioned solution also predicts the Doebner-Goldin equation which emerges to represent a form of long-sought quantum wave equation including gravity. A critical review of the key experiments is given which suggests that the IED process underlies the basic particle equations and properties not just sufficiently but also necessarily.
Effect of laser polarization on quantum electrodynamical cascading
Bashmakov, V. F.; Nerush, E. N.; Kostyukov, I. Yu.; Fedotov, A. M.; Narozhny, N. B.
2014-01-15
Development of quantum electrodynamical (QED) cascades in a standing electromagnetic wave for circular and linear polarizations is simulated numerically with a 3D PIC-MC code. It is demonstrated that for the same laser energy the number of particles produced in a circularly polarized field is greater than in a linearly polarized field, though the acquiring mean energy per particle is larger in the latter case. The qualitative model of laser-assisted QED cascades is extended by including the effect of polarization of the field. It turns out that cascade dynamics is notably more complicated in the case of linearly polarized field, where separation into the qualitatively different “electric” and “magnetic” regions (where the electric field is stronger than the magnetic field and vice versa) becomes essential. In the “magnetic” regions, acceleration is suppressed, and moreover the high-energy electrons are even getting cooled by photon emission. The volumes of the “electric” and “magnetic” regions evolve periodically in time and so does the cascade growth rate. In contrast to the linear polarization, the charged particles can be accelerated by circularly polarized wave even in “magnetic region.” The “electric” and “magnetic” regions do not evolve in time, and cascade growth rate almost does not depend on time for circular polarization.
The detection of gravitational waves using electrodynamic system of Earth
NASA Astrophysics Data System (ADS)
Grunskaya, Lubov; Isakevich, Valiriy
There is studied the interconnection of tide processes of geophysical and astrophysical origin with the Earth electromagnetic fields. There has been developed a programme-analytical system (PAS) to investigate signal structures in spectral and time series, caused by geophysical and astrophysical processes based on the method of eigen vectors. There were discovered frequencies in the electrical and geomagnetical field of ELF range with PAS, which coincide with the frequency of gravitational -wave radiation of a number of double stellar systems. In the electrical and geomagnetic field there was discovered a specific axion frequency VA=0.5*10-5 Hz belonging to the ELF range which was predicted by the theory. The problem of the anomalous behavior of the electrodynamic system response to the gravitational - wave affect is being discussed. On the basis of the rich experimental material have been investigated the frequencies of gravitational-wave radiation of a number of binary systems: J0700+6418, J1012+5307, J1537+1155, J1959+2048, J2130+1210, J1915+1606. The work is carried out with supporting of RFFI № 14-07-97510, State Task to Universities on 2014-2016.
Someya, Takeshi; Kobayashi, Mariko; Waguri, Satoshi; Ushiyama, Tomohiro; Nagaoka, Eiki; Hijikata, Wataru; Shinshi, Tadahiko; Arai, Hirokuni; Takatani, Setsuo
2009-09-01
MedTech Dispo, a disposable maglev centrifugal blood pump with two degrees of freedom magnetic suspension and radial magnetic coupling rotation, has been developed for 1-month extracorporeal circulatory support. As the first stage of a two-stage in vivo evaluation, 2-week evaluation of a prototype MedTech Dispo was conducted. In in vitro study, the pump could produce 5 L/min against 800 mm Hg and the normalized index of hemolysis was 0.0054 +/- 0.0008 g/100 L. In in vivo study, the pump, with its blood-contacting surface coated with biocompatible 2-methacryloyloxyethyl phosphorylcholine polymer, was implanted in seven calves in left heart bypass. Pump performance was stable with a mean flow of 4.49 +/- 0.38 L/min at a mean speed of 2072.1 +/- 64.5 rpm. The maglev control revealed its stability in rotor position during normal activity by the calves. During 2 weeks of operation in two calves which survived the intended study period, no thrombus formation was seen inside the pump and levels of plasma free hemoglobin were maintained below 4 mg/dL. Although further experiments are required, the pump demonstrated the potential for sufficient and reliable performance and biocompatibility in meeting the requirements for cardiopulmonary bypass and 1-week circulatory support.
Nagaoka, Eiki; Fujiwara, Tatsuki; Kitao, Takashi; Sakota, Daisuke; Shinshi, Tadahiko; Arai, Hirokuni; Takatani, Setsuo
2013-01-01
Short- to mid-term extracorporeal ventricular assist devices (VADs) are recommended for critical cardiogenic shock patients. We have designed a preclinical, single-use MedTech Mag-Lev VAD for one-month extracorporeal use. The impeller-rotor of the pump was suspended by a two degree-of-freedom active magnetic bearing in a 300 μm fluid gap, where the computational fluid dynamics analysis predicted a secondary flow of about 400-500 ml/min at a pump speed of 1800-2200 rpm. Three eddy current sensors were employed to implement noise- and drift-free magnetic levitation. The pump components were injection molded using polycarbonate for smooth surfaces as well as improved reproducibility, followed by coating with a biocompatible 2-methacryloyl-oxyethyl phosphorylcholine polymer. Chronic animal experiments were performed in nine calves. Three of the nine calves were excluded from analysis for problems with the circuit. Five of the six (83.3%) completed the 60 day duration of the study, while one prematurely died of massive bleeding due to inflow port detachment. The pump did not stop due to magnetic-levitation malfunction. Neither pump thrombosis nor major organ infarction was observed at autopsy. In comparison to machined surfaces, the injection-molded pump surfaces were thrombus-free after 60 day implantation. This study demonstrates the feasibility of MedTech Mag-Lev VAD for 60 day circulatory support.
NASA Astrophysics Data System (ADS)
Dietrich, Fred; Feero, William E.
1992-04-01
The safety of various magnetically levitated (maglev) and high speed rail (HSR) trains proposed for application in the United States is of direct concern to the Federal Railroad Administration (FRA). The characterization of electric and magnetic field (EMF) emissions, both steady (dc) and produced by alternating currents (ac) at power frequency (50 Hz in Europe and 60 Hz in the U.S.) and other frequencies in the Extreme Low Frequency (ELF) range (3-3000 Hz), and associated public and worker exposure to EMF, are a growing health and safety concern worldwide. As part of a comprehensive safety assessment of the German TransRapid (TR-07) maglev system undertaken by the FRA, with technical support from the DOT/RSPA Volpe National Transportation System Center (VNTSC), magnetic field measurements were performed by Electric Research and Management, Inc. (ERM) at the Transrapid Test Facility (TVE) in Emsland, Germany in August, 1990. Analysis summarizes the experimental findings and compares results to common home, work, and power lines emissions for selected spectral bands.
NASA Astrophysics Data System (ADS)
Dietrich, Fred; Robertson, David; Steiner, George
1992-04-01
The safety of various magnetically levitated (maglev) and high speed rail (HSR) trains proposed for application in the United States is of direct concern to the Federal Railroad Administration (FRA). The characterization of electric and magnetic fields (EMF) emissions, both steady (dc) and produced by alternating current (ac) at power frequency (50 Hz in Europe and 60 Hz in the U.S.) and other frequencies in the Extreme Low Frequency (ELF) range (3-3000 Hz), and associated public and worker exposures to EMF, are a growing health and safety concern worldwide. As part of a comprehensive safety assessment of the German TransRapid (TR-07) maglev system undertaken by the FRA, with technical support from the DOT/RSPA Volpe National Transportation System Center (VNTSC), magnetic field measurements were performed by Electric Research and Management, Inc. (ERM) at the Transrapid Test Facility (TVE) in Emsland, Germany in August, 1990. Appendices include catalogs and documents detailing magnetic field data files and their specifics (static fields, spectral waveforms, and temporal and spatial information) by location.
NASA Astrophysics Data System (ADS)
Wu, Ya-Bo; Zhang, Cheng-Yuan; Lu, Jian-Bo; Hu, Mu-Hong; Chai, Yun-Tian
2017-04-01
We numerically investigate the holographic paramagnetism-ferromagnetism phase transition in the 4-dimensional Lifshitz spacetime in the presence of three kinds of typical Born-Infeld-like nonlinear electrodynamics. Concretely, in the probe limit, we thoroughly discuss the effects of the nonlinear parameter b and the dynamical exponent z on the critical temperature, magnetic moment and hysteresis loop. The results show that the exponential form of nonlinear electrodynamics correction makes the critical temperature smaller and the magnetic moment harder to form with the absent external field for a constant nonlinear parameter b comparing it with the logarithmic form of nonlinear electrodynamics and the Born-Infeld nonlinear electrodynamics, especially for the case of larger dynamical exponent z. Moreover, the increase of nonlinear parameter b (for the fixed z) or dynamical exponent z (for the fixed b) will result in extending the period of the external magnetic field. Particularly, the effect of the exponential form of nonlinear electrodynamics on the periodicity of hysteresis loop is more noteworthy.
Long term dynamics and optimal control of nano-satellite deorbit using a short electrodynamic tether
NASA Astrophysics Data System (ADS)
Zhong, R.; Zhu, Z. H.
2013-10-01
This paper studies the long term dynamics and optimal control of a nano-satellite deorbit by a short electrodynamic tether. The long term deorbit process is discretized into intervals and within each interval a two-phase optimal control law is proposed to achieve libration stability and fast deorbit simultaneously. The first-phase formulates an open-loop fast-deorbit control trajectory by a simplified model that assumes the slow-varying orbital elements of electrodynamic tethered system as constant and ignores perturbation forces other than the electrodynamic force. The second phase tracks the optimal trajectory derived in the first phase by a finite receding horizon control method while considering a full dynamic model of electrodynamic tether system. Both optimal control problems are solved by direct collocation method base on the Hermite-Simpson discretization schemes with coincident nodes. The resulting piecewise nonlinear programing problems in the sequential intervals reduces the problem size and improve the computational efficiency, which enable an on-orbit control application. Numerical results for deorbit control of a short electrodynamic tethered nano-satellite system in both equatorial and highly inclined orbits demonstrate the efficiency of the proposed control method. An optimal balance between the libration stability and a fast deorbit of satellite with minimum control efforts is achieved.
Plasma Interactions with a Negative Biased Electrodynamic Tether
NASA Technical Reports Server (NTRS)
Vaughn, Jason A.; Welzyn, Ken J.; Curtis, Leslie
2003-01-01
The ProSEDS conductive tether design incorporates two distinct types of tethers from a plasma interaction viewpoint. The 200 m closest to the Delta 11 spacecraft is insulated from the plasma, and the remaining 5000 m is semi-bare. This latter portion is semi-bare because it has a conductive coating applied to the wires to permit electron collection while also regulating the overall tether temperature. Because the tether possesses these two distinct types of tethers, a transition point exists between the two types that form a triple point with the space plasma. Insulated tethers can suffer from a second plasma interaction if the insulation is weakened or breached, such as by pinholes caused by small particle debris strikes. Because electrodynamic tethers are typically long, they have a high probability of such impacts. These impacting particles may not be of sufficient size to severe the tether, but they can easily be of sufficient size to damage the tether insulation. Samples of both the ProSEDS tether transition region and the insulated tether section (with various degrees of pinhole damage) were placed into the MSFC plasma chamber and biased to typical ProSEDS open circuit tether potentials (-500 V to -1600 V). The results of the testing showed that the transition region of the tether (i.e. the triple point) arced and burned the tether in two at -900 V, and the damaged insulated sections arced and burned in two between -1000 V and -1600, depending on the pinhole damage geometry. tether design and make the tether ready for flight. To reduce the pinhole arcing risk, ProSEDS mission operations were changed to eliminate the negative potential on the tether. The results of the testing campaign and the design changes implemented to ensure a successful flight will be described.
Subsystem approach to the electrodynamics in dielectric fluids
NASA Astrophysics Data System (ADS)
Kemp, Brandon A.
2012-10-01
A century has now passed since the origins of the Abraham-Minkowski controversy pertaining to the correct form of optical momentum in media. Since, the debate has come to reference the general debate over optical momentum, including a number of competing formulations. The pervasive modern view is that the Abraham momentum represents the optical momentum contained within the fields and the Minkowski momentum includes a material component which is coupled with the fields. A recently proposed resolution to the debate identified Abraham's kinetic momentum as responsible for the overall center-of-mass translations of a medium and Minkowski's canonical momentum as responsible for local translations of a medium within or with respect to another medium. Still, current literature reveals significant confusion as to how systems of light and matter should be modeled as to deduce the equations of motion when multiple material types are present. For example, the state-of-the-art model for optical dynamics of submerged particles assumes over damped systems such that the mass of the particles is ignored in the equations of motion. In this paper, we apply the subsystem approach to deduce the electrodynamics of such systems. We show that regardless of which electromagnetic momentum continuity law is applied, the equations of motion can be correctly deduced as long as the continuity law is consistent with Maxwells equations and the overall system is closed such that momentum is conserved. Because the closed system includes the material response, the model can be very complex. However, we demonstrate with simple, well-known examples.
Generalized noise terms for the quantized fluctuational electrodynamics
NASA Astrophysics Data System (ADS)
Partanen, Mikko; Häyrynen, Teppo; Tulkki, Jukka; Oksanen, Jani
2017-03-01
The quantization of optical fields in vacuum has been known for decades, but extending the field quantization to lossy and dispersive media in nonequilibrium conditions has proven to be complicated due to the position-dependent electric and magnetic responses of the media. In fact, consistent position-dependent quantum models for the photon number in resonant structures have only been formulated very recently and only for dielectric media. Here we present a general position-dependent quantized fluctuational electrodynamics (QFED) formalism that extends the consistent field quantization to describe the photon number also in the presence of magnetic field-matter interactions. It is shown that the magnetic fluctuations provide an additional degree of freedom in media where the magnetic coupling to the field is prominent. Therefore, the field quantization requires an additional independent noise operator that is commuting with the conventional bosonic noise operator describing the polarization current fluctuations in dielectric media. In addition to allowing the detailed description of field fluctuations, our methods provide practical tools for modeling optical energy transfer and the formation of thermal balance in general dielectric and magnetic nanodevices. We use QFED to investigate the magnetic properties of microcavity systems to demonstrate an example geometry in which it is possible to probe fields arising from the electric and magnetic source terms. We show that, as a consequence of the magnetic Purcell effect, the tuning of the position of an emitter layer placed inside a vacuum cavity can make the emissivity of a magnetic emitter to exceed the emissivity of a corresponding electric emitter.
Plasma Interactions With a Negative Biased Electrodynamic Tether
NASA Technical Reports Server (NTRS)
Vaughn, Jason A.; Curtis, Leslie; Welzyn, Ken J.
2004-01-01
The ProSEDS conductive tether design incorporates two distinct types of tethers from a plasma interaction viewpoint. The 200 m closest to the Delta II spacecraft is insulated from the plasma, and the remaining 4800 m is semi-bare. This latter portion is considered semi-bare because a conductive coating, which is designed to collect electrons from the plasma, was applied to the wires to regulate the overall tether temperature. Because the tether has both insulating and conductive tether sections, a transition point exists between the two that forms a triple point with the space plasma. Also, insulated tethers can arc to the space plasma if the insulation is weakened or breached by pinholes caused by either improper handling or small meteoroid and orbital debris strikes. Because electrodynamic tethers are typically long, they have a high probability of these impacts. The particles, which strike the tether, may not have sufficient size to severe the tether, but they can easily penetrate the tether insulation producing a plasma discharge to the ambient plasma. Samples of both the ProSEDS tether transition region and the insulated tether section with various size of pinholes were placed into the MSFC plasma chamber and biased to typical ProSEDS open circuit tether potentials (-500 V to -1600 V). The results of the testing showed that the transition region of the tether (i.e. the triple point) arced to the ambient plasma at -900 V, and the tethers damaged by a pinhole or simulated debris strike arced to the plasma between -700 V and -900 V. Specific design steps were taken to eliminate the triple point issue in the ProSEDS tether design and make it ready for flight. To reduce the pinhole arcing risk, ProSEDS mission operations were changed to eliminate the high negative potential on the insulated tether. The results of the testing campaign and the design changes implemented to ensure a successful flight are described.
On the self-force in Bopp-Podolsky electrodynamics
NASA Astrophysics Data System (ADS)
Gratus, Jonathan; Perlick, Volker; Tucker, Robin W.
2015-10-01
In the classical vacuum Maxwell-Lorentz theory the self-force of a charged point particle is infinite. This makes classical mass renormalization necessary and, in the special relativistic domain, leads to the Abraham-Lorentz-Dirac equation of motion possessing unphysical run-away and pre-acceleration solutions. In this paper we investigate whether the higher-order modification of classical vacuum electrodynamics suggested by Bopp, Landé, Thomas and Podolsky in the 1940s, can provide a solution to this problem. Since the theory is linear, Green-function techniques enable one to write the field of a charged point particle on Minkowski spacetime as an integral over the particle’s history. By introducing the notion of timelike worldlines that are ‘bounded away from the backward light-cone’ we are able to prescribe criteria for the convergence of such integrals. We also exhibit a timelike worldline yielding singular fields on a lightlike hyperplane in spacetime. In this case the field is mildly singular at the event where the particle crosses the hyperplane. Even in the case when the Bopp-Podolsky field is bounded, it exhibits a directional discontinuity as one approaches the point particle. We describe a procedure for assigning a value to the field on the particle worldline which enables one to define a finite Lorentz self-force. This is explicitly derived leading to an integro-differential equation for the motion of the particle in an external electromagnetic field. We conclude that any worldline solutions to this equation belonging to the categories discussed in the paper have continuous four-velocities.
Scintillation Observations and Response of The Ionosphere to Electrodynamics (SORTIE)
NASA Astrophysics Data System (ADS)
Crowley, G.
2015-12-01
The Scintillation Observations and Response of The Ionosphere to Electrodynamics, or SORTIE, mission is a 6U NASA Heliophysics CubeSat designed to study the ionosphere at altitudes below 400km. The SORTIE mission is being developed by a team including ASTRA (lead institution), AFRL, University of Texas at Dallas (UTD), COSMIAC (Satellite Integrator), and Boston College. SORTIE will address cutting-edge science in the area of ionospheric dynamics. The SORTIE mission will address the following science questions: Q1) Discover the sources of wave-like plasma perturbations in the F-region ionosphere. Q2) Determine the relative role of dynamo action and more direct mechanical forcing in the formation of wave-like plasma perturbations. To address these questions we plan to fly a CubeSat with novel sensors that measure key plasma parameters in a circular, low to middle inclination orbit near 350-400 km altitude. The sensors include an ion velocity meter (built by UTD) and a Planar Langmuir Probe (built by AFRL). The SORTIE mission plan is to describe the distribution of wave-like structures in the plasma density of the ionospheric F-region. In doing so, the SORTIE team will determine the possible role of these perturbations in aiding the growth of plasma instabilities. SORTIE will provide (1) the initial spectrum of wave perturbations which are the starting point for the RT calculation; (2) measured electric fields which determine the magnitude of the instability growth rate near the region where plasma bubbles are generated; (3) initial observations of irregularities in plasma density which result from RT growth. SORTIE results will be used as input to PBMOD, an assimilative first-principles physical model of the ionosphere, in order to predict evolution of EPBs. In this presentation, we will review the science objectives, provide an overview of the spacecraft and instrument design, and present a concept of operations plan.
Towards a Unified Field Theory for Classical Electrodynamics
NASA Astrophysics Data System (ADS)
Benci, Vieri; Fortunato, Donato
2004-09-01
In this paper we introduce a model which describes the relation of matter and the electromagnetic field from a unitarian standpoint in the spirit of ideas of Born and Infeld. In this model, based on a semilinear perturbation of Maxwell equations, the particles are finite-energy solitary waves due to the presence of the nonlinearity. In this respect the matter and the electromagnetic field have the same nature. Finite energy means that particles have finite mass and this makes electrodynamics consistent with the special relativity. We analyze the invariants of the motion of the semilinear Maxwell equations (SME) and their static solutions. In the magnetostatic case (i.e., when the electric field E = 0 and the magnetic field H does not depend on time) SME are reduced to the semilinear equation where ∇× denotes the curloperator, f‧ is the gradient of a strictly convex smooth function f:R3→R and A:R3→R3 is the gauge potential related to the magnetic field H (H = ∇× A). Due to the presence of the curl operator, (1) is a strongly degenerate elliptic equation. Moreover, physical considerations impel f to be flat at zero (f‧‧(0)=0) and this fact leads us to study the problem in a functional setting related to the Orlicz space Lp+Lq. The existence of a nontrivial finite- energy solution of (1) is proved under suitable growth conditions on f. The proof is carried out by using a suitable variational framework related to the Hodge splitting of the vector field A.
Electrodynamics of relativistic electron beam x-ray sources
NASA Astrophysics Data System (ADS)
Niknejadi, Pardis
gun has been enhanced and/or the optical cavity (the final step of this proof-of-principle experiment) has been commissioned. Due to the complexity of this integrated system, one of the goals of this work is to serve the future members and staff of the UH FEL laboratory in configuring and operating this complex system. The final goal of the UH ICS project is to establish the principles on which producing a successful turn-key commercial inverse-Compton x-ray source will depend on. In the second part of this work we start with the discussion of coherent radiation at its most fundamental level, with emphasis on conservation of energy. We show that for coherently radiating particles the failure of conventional classical electrodynamics (CED) is far more serious than the well-known failure of CED at small scales. We will present a covariant picture of radiation in terms of the theory of action-at-a-distance and introduce a time-symmetric approach to electrodynamics. We demonstrate that this time symmetric approach provides a perfect match to the energy radiated by two coherently oscillating charged particles. This work is novel, as this was an unsolved problem in classical electrodynamics up until now. We also discuss how the conceptual implication of this work is demanding. For this purpose, we will propose two different experiments that can further our understanding of the presented problem. The first experiment involves a small (lambda/10) antenna, and the goal is to measure the advanced field of the absorber at distances of 5lambda or less. Calculation and precise measurement of the antenna field/potential at distances of order lambda is challenging, causing this experiment to be a difficult yet possible task. In the second experiment, we discuss in some detail the experimental setup that would verify and/or further our understanding of the underlying physics of Self Amplified Spontaneous Emission (SASE) FELs. We provide an analytical verification as a first step
NASA Astrophysics Data System (ADS)
Curé, Jorge C.
1982-10-01
The probable existence of a new electrodynamic field is obtained by analogy with the general theory of relativity. The new field is derived from a scalar electrodynamic potential which is similar to the Edwards potential discovered experimentally in recent years. A modification of the Millikan oil drop experiment is also suggested to empirically verify the new field avoiding misinterpretations of Edwards' results.
Four-dimensional black holes with scalar hair in nonlinear electrodynamics
NASA Astrophysics Data System (ADS)
Barrientos, José; González, P. A.; Vásquez, Yerko
2016-12-01
We consider a gravitating system consisting of a scalar field minimally coupled to gravity with a self-interacting potential and a U(1) nonlinear electromagnetic field. Solving analytically and numerically the coupled system for both power-law and Born-Infeld type electrodynamics, we find charged hairy black hole solutions. Then we study the thermodynamics of these solutions and we find that at a low temperature the topological charged black hole with scalar hair is thermodynamically preferred, whereas the topological charged black hole without scalar hair is thermodynamically preferred at a high temperature for power-law electrodynamics. Interestingly enough, these phase transitions occur at a fixed critical temperature and do not depend on the exponent p of the nonlinear electrodynamics.
Class of gauge-invariant models of quantum electrodynamics with nonlocal interaction
Mei, Tao
2017-01-01
We present a class of gauge-invariant models of quantum electrodynamics with nonlocal interaction. The models have translation, Lorentz and gauge invariance and reduce to the conventional local quantum electrodynamics under the appropriate limit conditions, both the equations of motion of the charged particle and electromagnetic field obtained by the action principle lead to the normal form of current conservation. Quantization of the models is realized by taking advantage of the formalism based on the Yang-Feldman equations and the Lehmann-Symanzik-Zimmermann reduction formulas. Finally, we employ a special choice of the models to calculate the vacuum polarization as an example to demonstrate the possibility of establishing a theory of quantum electrodynamics without divergence. PMID:28368044
Class of gauge-invariant models of quantum electrodynamics with nonlocal interaction.
Mei, Tao
2017-04-03
We present a class of gauge-invariant models of quantum electrodynamics with nonlocal interaction. The models have translation, Lorentz and gauge invariance and reduce to the conventional local quantum electrodynamics under the appropriate limit conditions, both the equations of motion of the charged particle and electromagnetic field obtained by the action principle lead to the normal form of current conservation. Quantization of the models is realized by taking advantage of the formalism based on the Yang-Feldman equations and the Lehmann-Symanzik-Zimmermann reduction formulas. Finally, we employ a special choice of the models to calculate the vacuum polarization as an example to demonstrate the possibility of establishing a theory of quantum electrodynamics without divergence.
NASA Astrophysics Data System (ADS)
Milton, Kimball A.
2007-01-01
Julian Schwinger’s influence on twentieth-century science is profound and pervasive. He is most famous for his renormalization theory of quantum electrodynamics, for which he shared the Nobel Prize in Physics for 1965 with Richard Feynman and Sin-itiro Tomonaga. This triumph undoubtedly was his most heroic work, but his legacy lives on chiefly through subtle and elegant work in classical electrodynamics, quantum variational principles, proper-time methods, quantum anomalies, dynamical mass generation, partial symmetry, and much more. Starting as just a boy, he rapidly became one of the preeminent nuclear physicists in the world in the late 1930s, led the theoretical development of radar technology at the Massachusetts Institute of Technology during World War II, and soon after the war conquered quantum electrodynamics, becoming the leading quantum-field theorist for two decades, before taking a more iconoclastic route during the last quarter century of his life.
On analytical study of holographic superconductors with Born-Infeld electrodynamics
NASA Astrophysics Data System (ADS)
Lai, Chuyu; Pan, Qiyuan; Jing, Jiliang; Wang, Yongjiu
2015-10-01
Based on the Sturm-Liouville eigenvalue problem, Banerjee et al. proposed a perturbative approach to analytically investigate the properties of the (2 + 1)-dimensional superconductor with Born-Infeld electrodynamics (Banerjee et al., 2013) [29]. By introducing an iterative procedure, we will further improve the analytical results and the consistency with the numerical findings, and can easily extend the analytical study to the higher-dimensional superconductor with Born-Infeld electrodynamics. We observe that the higher Born-Infeld corrections make it harder for the condensation to form but do not affect the critical phenomena of the system. Our analytical results can be used to back up the numerical computations for the holographic superconductors with various condensates in Born-Infeld electrodynamics.
Geometrothermodynamics of black holes in Lovelock gravity with a nonlinear electrodynamics
NASA Astrophysics Data System (ADS)
Hendi, S. H.; Naderi, R.
2015-01-01
The objective of the present paper is to analyze the phase transition of asymptotically anti-de Sitter (AdS) black-hole solutions in Lovelock gravity in the presence of nonlinear electrodynamics. First, we present the asymptotically AdS black-hole solutions for two classes of the Born-Infeld type of nonlinear electrodynamics coupled (separately) with Einstein, Gauss-Bonnet, and third-order Lovelock gravity. Then, in order to discuss the phase transition, we calculate both the heat capacity and the Ricci scalar of the thermodynamical line element. We present a comparison between the singular points of the Ricci scalar using the geometrothermodynamics method and the corresponding vanishing points of the heat capacity in the canonical ensemble. In addition, we discuss the effects of both Lovelock and nonlinear electrodynamics on the phase transition points.
NASA Astrophysics Data System (ADS)
Yizengaw, E.; Moldwin, M.; Zesta, E.
2015-12-01
The currently funded African Meridian B-Field Education and Research (AMBER) magnetometer array comprises more than thirteen magnetometers stationed globally in the vicinity of geomagnetic equator. One of the main objectives of AMBER network is to understand the longitudinal variability of equatorial electrodynamics as function of local time, magnetic activity, and season. While providing complete meridian observation in the region and filling the largest land-based gap in global magnetometer coverage, the AMBER array addresses two fundamental areas of space physics: first, the processes governing electrodynamics of the equatorial ionosphere as a function of latitude (or L-shell), local time, longitude, magnetic activity, and season, and second, ULF pulsation strength at low/mid-latitude regions and its connection with equatorial electrojet and density fluctuation. The global AMBER network can also be used to augment observations from space-based instruments, such us the triplet SWARM mission and the upcoming ICON missions. Thus, in coordination with space-based and other ground-based observations, the AMBER magnetometer network provides a great opportunity to understand the electrodynamics that governs equatorial ionosphere motions. In this paper we present the longitudinal variability of the equatorial electrodynamics using the combination of instruments onboard SWARM and C/NOFS satellites and ground-based AMBER network. Both ground- and pace-based observations show stronger dayside and evening sector equatorial electrodynamics in the American and Asian sectors compared to the African sector. On the other hand, the African sector is home to stronger and year-round ionospheric bubbles/irregularities compared to the American and Asian sectors. This raises the question if the evening sector equatorial electrodynamics (vertical drift), which is believed to be the main cause for the enhancement of Rayleigh-Taylor (RT) instability growth rate, is stronger in the
Smith, Richard D.; Tang, Keqi; Shvartsburg, Alexandre A.
2004-11-16
A method and apparatus enabling increased sensitivity in ion mobility spectrometry/mass spectrometry instruments which substantially reduces or eliminates the loss of ions in ion mobility spectrometer drift tubes utilizing an hourglass electrodynamic ion funnel at the entrance to the drift tube and/or an internal ion funnel at the exit of the drift tube. An hourglass electrodynamic funnel is formed of at least an entry element, a center element, and an exit element, wherein the aperture of the center element is smaller than the aperture of the entry element and the aperture of the exit elements. Ions generated in a relatively high pressure region by an ion source at the exterior of the hourglass electrodynamic funnel are transmitted to a relatively low pressure region at the entrance of the hourglass funnel through a conductance limiting orifice. Alternating and direct electrical potentials are applied to the elements of the hourglass electrodynamic funnel thereby drawing ions into and through the hourglass electrodynamic funnel thereby introducing relatively large quantities of ions into the drift tube while maintaining the gas pressure and composition at the interior of the drift tube as distinct from those at the entrance of the electrodynamic funnel and allowing a positive gas pressure to be maintained within the drift tube, if desired. An internal ion funnel is provided within the drift tube and is positioned at the exit of said drift tube. The advantage of the internal ion funnel is that ions that are dispersed away from the exit aperture within the drift tube, such as those that are typically lost in conventional drift tubes to any subsequent analysis or measurement, are instead directed through the exit of the drift tube, vastly increasing the amount of ions exiting the drift tube.
Smith, Richard D.; Tang, Keqi; Shvartsburg, Alexandre A.
2005-11-22
A method and apparatus enabling increased sensitivity in ion mobility spectrometry/mass spectrometry instruments which substantially reduces or eliminates the loss of ions in ion mobility spectrometer drift tubes utilizing a device for transmitting ions from an ion source which allows the transmission of ions without significant delay to an hourglass electrodynamic ion funnel at the entrance to the drift tube and/or an internal ion funnel at the exit of the drift tube. An hourglass electrodynamic funnel is formed of at least an entry element, a center element, and an exit element, wherein the aperture of the center element is smaller than the aperture of the entry element and the aperture of the exit elements. Ions generated in a relatively high pressure region by an ion source at the exterior of the hourglass electrodynamic funnel are transmitted to a relatively low pressure region at the entrance of the hourglass funnel through a conductance limiting orifice. Alternating and direct electrical potentials are applied to the elements of the hourglass electrodynamic funnel thereby drawing ions into and through the hourglass electrodynamic funnel thereby introducing relatively large quantities of ions into the drift tube while maintaining the gas pressure and composition at the interior of the drift tube as distinct from those at the entrance of the electrodynamic funnel and allowing a positive gas pressure to be maintained within the drift tube, if desired. An internal ion funnel is provided within the drift tube and is positioned at the exit of said drift tube. The advantage of the internal ion funnel is that ions that are dispersed away from the exit aperture within the drift tube, such as those that are typically lost in conventional drift tubes to any subsequent analysis or measurement, are instead directed through the exit of the drift tube, vastly increasing the amount of ions exiting the drift tube.
Holographic superconductors in Gauss-Bonnet gravity with Born-Infeld electrodynamics
Jing Jiliang; Wang Liancheng; Pan Qiyuan; Chen Songbai
2011-03-15
We investigate the holographic superconductors in Gauss-Bonnet gravity with Born-Infeld electrodynamics. We find that the Gauss-Bonnet constant, the model parameters, and the Born-Infeld coupling parameter will affect the formation of the scalar hair, the transition point of the phase transition from the second order to the first order, and the relation connecting the gap frequency in conductivity with the critical temperature. The combination of Gauss-Bonnet gravity and the Born-Infeld electrodynamics provides richer physics in the phase transition and the condensation of the scalar hair.
NASA Astrophysics Data System (ADS)
Sheykhi, A.; Hajkhalili, S.
2015-11-01
We study topological dilaton black holes of Einstein gravity in the presence of exponential nonlinear electrodynamics. The event horizons of these black holes can be a two-dimensional positive, zero or negative constant curvature surface. We analyze thermodynamics of these solutions by calculating all conserved and thermodynamic quantities and showing that the first law holds on the black hole horizon. Then, we perform the stability analysis in both canonical and grand canonical ensemble and disclose the effects of the dilaton and nonlinear electrodynamics on the thermal stability of the solutions. Finally, we study the phase transition points of these black holes in the thermodynamic geometry approach.
Single photon delayed feedback: a way to stabilize intrinsic quantum cavity electrodynamics.
Carmele, Alexander; Kabuss, Julia; Schulze, Franz; Reitzenstein, Stephan; Knorr, Andreas
2013-01-04
We propose a scheme to control cavity quantum electrodynamics in the single photon limit by delayed feedback. In our approach a single emitter-cavity system, operating in the weak coupling limit, can be driven into the strong coupling-type regime by an external mirror: The external loop produces Rabi oscillations directly connected to the electron-photon coupling strength. As an expansion of typical cavity quantum electrodynamics, we treat the quantum correlation of external and internal light modes dynamically and demonstrate a possible way to implement a fully quantum mechanical time-delayed feedback. Our theoretical approach proposes a way to experimentally feedback control quantum correlations in the single photon limit.
Some Quantum Experiments from the Point of View of Stochastic Electrodynamics
NASA Astrophysics Data System (ADS)
Špička, V.; Mareš, J. J.; Hubík, P.; Krištofik, J.
2007-09-01
Stochastic electrodynamics (SED), an alternative theory to quantum phenomena based on laws of classical physics is shortly reviewed and compared with quantum electrodynamics. Experiments supporting the existence of zero-point fluctuating radiation field, the key concept of SED, are discussed. Relation between measurements of the black-body radiation spectrum and noise is analysed to define conditions under which the zero-point component of radiation or noise can be observed. Further, it is shown that stability of weakly localized orbits, measured in disordered solid state systems, can be explained by the presence of zero-point fluctuations of vacuum.
NASA Astrophysics Data System (ADS)
Olsen, M. K.; Dechoum, K.; Plimak, L. I.
2001-04-01
We show that stochastic electrodynamics and quantum mechanics give quantitatively different predictions for the quantum nondemolition (QND) correlations in travelling wave second harmonic generation. Using phase space methods and stochastic integration, we calculate correlations in both the positive-P and truncated Wigner representations, the latter being equivalent to the semi-classical theory of stochastic electrodynamics. We show that the semi-classical results are different in the regions where the system performs best in relation to the QND criteria, and that they significantly overestimate the performance in these regions.
Stochastic electrodynamics with particle structure Part I: Zero-point induced Brownian behavior
NASA Astrophysics Data System (ADS)
Rueda, A.
1993-02-01
If ordinary views on particle structure are introduced in a simple classical particle model in replacement of the point particles of standard use in stochastic electrodynamics, it can be shown that an internal Zitterbewegung induced by the zero-point field background gives rise to a Brownian movement for the whole particle with a diffusion constant of the form D = ħ/2mD , where mD is a modeldependent mass. Since the days of Madeleung and Fuhr brownian behaviour has often been associated with quantization. We discuss this from the viewpoint of stochastic electrodynamics.
Orbit Optimization For The Geospace Electrodynamics Connections (GEC) Mission
NASA Technical Reports Server (NTRS)
Mesarch, Michael A.
2004-01-01
Part of NASA's Solar Terrestrial Probe line of missions, the Geospace Electrodynamics Connections (GEC) mission will deploy a formation of three spacecraft to perform in-situ atmospheric research in the low Ionosphere-Thermosphere region. These spacecraft will fly together in a %tring-of-pearls formation with variable spacings ranging from 10 seconds to one-quarter of an orbit at perigee. Over the course of its two-year mission, the three spacecraft will perform ten, 1-week dipping campaigns whereby they maneuver to lower their perigee to near 134 km. Using available launch vehicle performance data, an optimal parking orbit of 222 x 1525 km was found to maximize the dry mass available while providing enough propellant to perform the ten deep-dipping campaigns over its two-year mission. The results were used to create multi-variable contour plots containing the orbit perigee, the orbit apogee, spacecraft dry mass, propellant mass, and T500 (a science data collection figure of merit that tabulates the cumulative time spent below 500 km). These plots illustrate how the mission can trade off science return relative to the cost in dry mass and propellant. Other optimal solutions such as minimum propellant or maximum T500 were found to either limit the science data collection or to be dry mass limiting, respectively. Sensitivity analyses were performed to find new optimal (maximum dry mass) solutions if the number of campaigns changed, if the coefficient of drag (CD) were different, and if the propellant specific impulse were increased. A surprising result showed that the dry mass and T500 were both increased if the number of campaigns decreased. Changes in CD provided the expected results - raising CD lowered both the dry mass and T500 while lowering CD raised both the dry mass and T500. Increases in the propellant specific impulse had the expected outcome of raising the dry mass and lowering the propellant load but there was no change in the T500 figure of merit. The
Apparent Paradoxes in Classical Electrodynamics: A Fluid Medium in an Electromagnetic Field
ERIC Educational Resources Information Center
Kholmetskii, A. L.; Yarman, T.
2008-01-01
In this paper we analyse a number of teaching paradoxes of classical electrodynamics, dealing with the relativistic transformation of energy and momentum for a fluid medium in an external electromagnetic field. In particular, we consider a moving parallel plate charged capacitor, where the electric attraction of its plates is balanced by the…
Methods of numerical analysis of 1-dimensional 2-body problem in Wheeler-Feynman electrodynamics
NASA Astrophysics Data System (ADS)
Klimenko, S. V.; Nikitin, I. N.; Urazmetov, W. F.
2000-04-01
Numerical methods for solution of differential equations with deviating arguments describing 1-dimensional ultra-relativistic scattering of 2 identical charged particles in classical electrodynamics with half-retarded/halfadvanced interaction (Wheeler and Feynman, 1949) are developed. A bifurcation of solutions and violation of their reflectional symmetries in the region of velocities v>0.937c are found in numerical analysis.
ERIC Educational Resources Information Center
Gsponer, Andre
2009-01-01
The objective of this introduction to Colombeau algebras of generalized functions (in which distributions can be freely multiplied) is to explain in elementary terms the essential concepts necessary for their application to basic nonlinear problems in classical physics. Examples are given in hydrodynamics and electrodynamics. The problem of the…
Toward proving a new identity for Green's functions in N = 1 supersymmetric electrodynamics
Stepanyantz, K. V.
2009-01-15
A method that may underlie an attempt at proving the previously proposed new identity for Green's functions is described for N = 1 supersymmetric massless electrodynamics regularized by higher derivatives. With the aid of this method, it is shown that some contributions to the identity in question do indeed vanish.
Payton, John L; Morton, Seth M; Moore, Justin E; Jensen, Lasse
2014-01-21
Surface-enhanced Raman scattering (SERS) is a technique that has broad implications for biological and chemical sensing applications by providing the ability to simultaneously detect and identify a single molecule. The Raman scattering of molecules adsorbed on metal nanoparticles can be enhanced by many orders of magnitude. These enhancements stem from a twofold mechanism: an electromagnetic mechanism (EM), which is due to the enhanced local field near the metal surface, and a chemical mechanism (CM), which is due to the adsorbate specific interactions between the metal surface and the molecules. The local field near the metal surface can be significantly enhanced due to the plasmon excitation, and therefore chemists generally accept that the EM provides the majority of the enhancements. While classical electrodynamics simulations can accurately simulate the local electric field around metal nanoparticles, they offer few insights into the spectral changes that occur in SERS. First-principles simulations can directly predict the Raman spectrum but are limited to small metal clusters and therefore are often used for understanding the CM. Thus, there is a need for developing new methods that bridge the electrodynamics simulations of the metal nanoparticle and the first-principles simulations of the molecule to facilitate direct simulations of SERS spectra. In this Account, we discuss our recent work on developing a hybrid atomistic electrodynamics-quantum mechanical approach to simulate SERS. This hybrid method is called the discrete interaction model/quantum mechanics (DIM/QM) method and consists of an atomistic electrodynamics model of the metal nanoparticle and a time-dependent density functional theory (TDDFT) description of the molecule. In contrast to most previous work, the DIM/QM method enables us to retain a detailed atomistic structure of the nanoparticle and provides a natural bridge between the electronic structure methods and the macroscopic
NASA Astrophysics Data System (ADS)
Matsuo, Tomoko; Knipp, Delores J.; Richmond, Arthur D.; Kilcommons, Liam; Anderson, Brian J.
2015-06-01
This paper presents an analysis of data from the magnetometers on board the Defense Meteorological Satellite Program (DMSP) F-15, F-16, F-17, and F-18 satellites and the Iridium satellite constellation, using an inverse procedure for high-latitude ionospheric electrodynamics, during the period of 29-30 May 2010. The Iridium magnetometer data are made available through the Active Magnetosphere and Planetary Electrodynamics Response Experiment (AMPERE) program. The method presented here is built upon the assimilative mapping of ionospheric electrodynamics procedure but with a more complete treatment of the prior model uncertainty to facilitate an optimal inference of complete polar maps of electrodynamic variables from irregularly distributed observational data. The procedure can provide an objective measure of uncertainty associated with the analysis. The cross-validation analysis, in which the DMSP data are used as independent validation data sets, suggests that the procedure yields the spatial prediction of DMSP perturbation magnetic fields from AMPERE data alone with a median discrepancy of 30-50 nT. Discrepancies larger than 100 nT are seen in about 20% of total samples, whose location and magnitude are generally consistent with the previously identified discrepancy between DMSP and AMPERE data sets. Resulting field-aligned current (FAC) patterns exhibit more distinct spatial patterns without spurious high-frequency oscillatory features in comparison to the FAC products provided by AMPERE. Maps of the toroidal magnetic potential and FAC estimated from both AMPERE and DMSP data under four distinctive interplanetary magnetic field (IMF) conditions during a magnetic cloud event demonstrate the IMF control of high-latitude electrodynamics and the opportunity for future scientific investigation.
NASA Astrophysics Data System (ADS)
Figliozzi, Patrick; Sule, Nishant; Yan, Zijie; Bao, Ying; Burov, Stanislav; Gray, Stephen K.; Rice, Stuart A.; Vaikuntanathan, Suriyanarayanan; Scherer, Norbert F.
2017-02-01
To date investigations of the dynamics of driven colloidal systems have focused on hydrodynamic interactions and often employ optical (laser) tweezers for manipulation. However, the optical fields that provide confinement and drive also result in electrodynamic interactions that are generally neglected. We address this issue with a detailed study of interparticle dynamics in an optical ring vortex trap using 150-nm diameter Ag nanoparticles. We term the resultant electrodynamically interacting nanoparticles a driven optical matter system. We also show that a superior trap is created by using a Au nanoplate mirror in a retroreflection geometry, which increases the electric field intensity, the optical drive force, and spatial confinement. Using nanoparticles versus micron sized colloids significantly reduces the surface hydrodynamic friction allowing us to access small values of optical topological charge and drive force. We quantify a further 50% reduction of hydrodynamic friction when the nanoparticles are driven over the Au nanoplate mirrors versus over a mildly electrostatically repulsive glass surface. Further, we demonstrate through experiments and electrodynamics-Langevin dynamics simulations that the optical drive force and the interparticle interactions are not constant around the ring for linearly polarized light, resulting in a strong position-dependent variation in the nanoparticle velocity. The nonuniformity in the optical drive force is also manifest as an increase in fluctuations of interparticle separation, or effective temperature, as the optical driving force is increased. Finally, we resolve an open issue in the literature on periodic modulation of interparticle separation with comparative measurements of driven 300-nm-diameter polystyrene beads that also clearly reveal the significance of electrodynamic forces and interactions in optically driven colloidal systems. Therefore, the modulations in the optical forces and electrodynamic interactions
Fujiwara, Tatsuki; Nagaoka, Eiki; Watanabe, Taiju; Miyagi, Naoto; Kitao, Takashi; Sakota, Daisuke; Mamiya, Taichi; Shinshi, Tadahiko; Arai, Hirokuni; Takatani, Setsuo
2013-05-01
We have evaluated the feasibility of a newly developed single-use, magnetically levitated centrifugal blood pump, MedTech Mag-Lev, in a 3-week extracorporeal membrane oxygenation (ECMO) study in calves against a Medtronic Bio-Pump BPX-80. A heparin- and silicone-coated polypropylene membrane oxygenator MERA NHP Excelung NSH-R was employed as an oxygenator. Six healthy male Holstein calves with body weights of about 100 kg were divided into two groups, four in the MedTech group and two in the Bio-Pump group. Under general anesthesia, the blood pump and oxygenator were inserted extracorporeally between the main pulmonary artery and the descending aorta via a fifth left thoracotomy. Postoperatively, both the pump and oxygen flow rates were controlled at 3 L/min. Heparin was continuously infused to maintain the activated clotting time at 200-240 s. All the MedTech ECMO calves completed the study duration. However, the Bio-Pump ECMO calves were terminated on postoperative days 7 and 10 because of severe hemolysis and thrombus formation. At the start of the MedTech ECMO, the pressure drop across the oxygenator was about 25 mm Hg with the pump operated at 2800 rpm and delivering 3 L/min flow. The PO2 of the oxygenator outlet was higher than 400 mm Hg with the PCO2 below 45 mm Hg. Hemolysis and thrombus were not seen in the MedTech ECMO circuits (plasma-free hemoglobin [PFH] < 5 mg/dL), while severe hemolysis (PFH > 20 mg/dL) and large thrombus were observed in the Bio-Pump ECMO circuits. Plasma leakage from the oxygenator did not occur in any ECMO circuits. Three-week cardiopulmonary support was performed successfully with the MedTech ECMO without circuit exchanges. The MedTech Mag-Lev could help extend the durability of ECMO circuits by the improved biocompatible performances.
History and Flight Devleopment of the Electrodynamic Dust Shield
NASA Technical Reports Server (NTRS)
Johansen, Michael R.; Mackey, Paul J.; Hogue, Michael D.; Cox, Rachel E.; Phillips, James R., III; Calle, Carlos I.
2015-01-01
The surfaces of the moon, Mars, and that of some asteroids are covered with a layer of dust that may hinder robotic and human exploration missions. During the Apollo missions, for example, lunar dust caused a number of issues including vision obscuration, false instrument readings, contamination, and elevated temperatures. In fact, some equipment neared failure after only 75 hours on the lunar surface due to effects of lunar dust. NASA's Kennedy Space Center has developed an active technology to remove dust from surfaces during exploration missions. The Electrodynamic Dust Shield (EDS), which consists of a series of embedded electrodes in a high dielectric strength substrate, uses a low power, low frequency signal that produces an electric field wave that travels across the surface. This non-uniform electric field generates dielectrophoretic and electrostatic forces capable of moving dust out of these surfaces. Implementations of the EDS have been developed for solar radiators, optical systems, camera lenses, visors, windows, thermal radiators, and fabrics The EDS implementation for transparent applications (solar panels, optical systems, windows, etc.) uses transparent indium tin oxide electrodes on glass or transparent lm. Extensive testing was performed in a roughly simulated lunar environment (one-sixth gravity at 1 mPa atmospheric pressure) with lunar simulant dust. EDS panels over solar radiators showed dust removal that restored solar panel output reaching values very close to their initial output. EDS implementations for thermal radiator protection (metallic spacecraft surfaces with white thermal paint and reflective films) were also extensively tested at similar high vacuum conditions. Reflectance spectra for these types of implementations showed dust removal efficiencies in the 96% to 99% range. These tests indicate that the EDS technology is now at a Technology Readiness Level of 4 to 5. As part of EDS development, a flight version is being prepared for
Venediktov, V Yu
2015-04-30
This methodological note is dedicated to the analysis of the imaginary experiment proposed in the paper by R.I. Khrapko 'On the possibility of an experiment on 'nonlocality' of electrodynamics' [Quantum Electronics, 42, 1133 (2012)]. (discussion)
Magnetically charged regular black hole in a model of nonlinear electrodynamics
Ma, Meng-Sen
2015-11-15
We obtain a magnetically charged regular black hole in general relativity. The source to the Einstein field equations is nonlinear electrodynamic field in a physically reasonable model of nonlinear electrodynamics (NED). “Physically” here means the NED model is constructed on the basis of three conditions: the Maxwell asymptotic in the weak electromagnetic field limit; the presence of vacuum birefringence phenomenon; and satisfying the weak energy condition (WEC). In addition, we analyze the thermodynamic properties of the regular black hole in two ways. According to the usual black hole thermodynamics, we calculate the heat capacity at constant charge, from which we know the smaller black hole is more stable. We also employ the horizon thermodynamics to discuss the thermodynamic quantities, especially the heat capacity at constant pressure.
NASA Astrophysics Data System (ADS)
Bogolubov, Nikolai N.; Prykarpatsky, Anatoliy K.
2010-05-01
The Lagrangian and Hamiltonian properties of classical electrodynamics models and their associated Dirac quantizations are studied. Using the vacuum field theory approach developed in (Prykarpatsky et al. Theor. Math. Phys. 160(2): 1079-1095, 2009 and The field structure of a vacuum, Maxwell equations and relativity theory aspects. Preprint ICTP) consistent canonical Hamiltonian reformulations of some alternative classical electrodynamics models are devised, and these formulations include the Lorentz condition in a natural way. The Dirac quantization procedure corresponding to the Hamiltonian formulations is developed. The crucial importance of the rest reference systems, with respect to which the dynamics of charged point particles is framed, is explained and emphasized. A concise expression for the Lorentz force is derived by suitably taking into account the duality of electromagnetic field and charged particle interactions. Finally, a physical explanation of the vacuum field medium and its relativistic properties fitting the mathematical framework developed is formulated and discussed.
NASA Astrophysics Data System (ADS)
Gsponer, Andre
2009-01-01
The objective of this introduction to Colombeau algebras of generalized functions (in which distributions can be freely multiplied) is to explain in elementary terms the essential concepts necessary for their application to basic nonlinear problems in classical physics. Examples are given in hydrodynamics and electrodynamics. The problem of the self-energy of a point electric charge is worked out in detail: the Coulomb potential and field are defined as Colombeau generalized functions, and integrals of nonlinear expressions corresponding to products of distributions (such as the square of the Coulomb field and the square of the delta function) are calculated. Finally, the methods introduced in Gsponer (2007 Eur. J. Phys. 28 267, 2007 Eur. J. Phys. 28 1021 and 2007 Eur. J. Phys. 28 1241), to deal with point-like singularities in classical electrodynamics are confirmed.
A Method for Stable Deployment of an Electrodynamic Tethered Satellite in Three-Dimensional Space
NASA Astrophysics Data System (ADS)
Yu, B. S.; Jin, D. P.; Wen, H.
2016-09-01
The paper presents an asymptotic stabilization strategy for the deployment of a controlled tethered satellite system in three-dimensional space, in which the tether length rate is taken as the control variable. Firstly, a rigid-rod tether model is employed to establish the nonlinear dynamic equations of in-plane and out-of-plane motions of the system. Then, by stability analysis of the linearized system at a preassigned direction to deploy, the control law and asymptotic stability condition for the deployment are obtained. The electrodynamic tethered satellite in equatorial plane is discussed. As a result, the large swing motions during deployment are stabilized asymptotically through reliance on the electrodynamic force and the tether length rate. The case studies in the paper well demonstrate the proposed stabilization control strategy.
Resonant electrodynamic heating of stellar coronal loops - An LRC circuit analog
NASA Technical Reports Server (NTRS)
Ionson, J. A.
1982-01-01
The problem of electrodynamic coupling of stellar coronal loops where beta is less than 1 to underlying velocity fields where beta is greater than approximately 1 is treated. A rigorous analysis reveals that the physics can be represented by a simple yet equivalent LRC circuit analog. This derived analog suggests the existence of global structure oscillations which resonantly excite internal field line oscillations at a spatial resonance within the coronal loop. Even though the width of this spatial resonance, as well as the induced currents and coronal velocity field, within the resonance region explicitly depends on viscosity and resistivity, the resonant form of the generalized electrodynamic heating functions is virtually independent of irreversibilities. This is a classic feature of high-quality resonators that are driven externally by a broad-band source of spectral power.
Resonant electrodynamic heating of stellar coronal loops: An LRC circuit analogue
NASA Technical Reports Server (NTRS)
Ionson, J. A.
1980-01-01
The electrodynamic coupling of stellar coronal loops to underlying beta velocity fields. A rigorous analysis revealed that the physics can be represented by a simple yet equivalent LRC circuit analogue. This analogue points to the existence of global structure oscillations which resonantly excite internal field line oscillations at a spatial resonance within the coronal loop. Although the width of this spatial resonance, as well as the induced currents and coronal velocity field, explicitly depend upon viscosity and resistivity, the resonant form of the generalized electrodynamic heating function is virtually independent of irreversibilities. This is a classic feature of high quality resonators that are externally driven by a broad band source of spectral power. Applications to solar coronal loops result in remarkable agreement with observations.
NASA Astrophysics Data System (ADS)
Dymnikova, Irina; Galaktionov, Evgeny
2016-03-01
In nonlinear electrodynamics minimally coupled to gravity, regular spherically symmetric electrically charged solutions satisfy the weak energy condition and have obligatory de Sitter center. By the Gürses-Gürsey algorithm they are transformed to regular axially symmetric solutions asymptotically Kerr-Newman for a distant observer. Rotation transforms de Sitter center into de Sitter equatorial disk embedded as a bridge into a de Sitter vacuum surface. The de Sitter surfaces satisfy p = -ρ and have properties of a perfect conductor and ideal diamagnetic. The Kerr ring singularity is replaced with the superconducting current which serves as a non-dissipative electromagnetic source of the asymptotically Kerr-Newman geometry. Violation of the weak energy condition is prevented by the basic requirement of electrodynamics of continued media.
Field theory on R× S 3 topology. IV: Electrodynamics of magnetic moments
NASA Astrophysics Data System (ADS)
Carmeli, M.; Malin, S.
1986-08-01
The equations of electrodynamics for the interactions between magnetic moments are written on R×S3 topology rather than on Minkowskian space-time manifold of ordinary Maxwell's equations. The new field equations are an extension of the previously obtained Klein-Gordon-type, Schrödinger-type, Weyl-type, and Dirac-type equations. The concept of the magnetic moment in our case takes over that of the charge in ordinary electrodynamics as the fundamental entity. The new equations have R×S3 invariance as compared to the Lorentz invariance of Maxwell's equations. The solutions of the new field equations are given. In this theory the divergence of the electric field vanishes whereas that of the magnetic field does not.
Quantized Faraday and Kerr rotation and axion electrodynamics of a 3D topological insulator.
Wu, Liang; Salehi, M; Koirala, N; Moon, J; Oh, S; Armitage, N P
2016-12-02
Topological insulators have been proposed to be best characterized as bulk magnetoelectric materials that show response functions quantized in terms of fundamental physical constants. Here, we lower the chemical potential of three-dimensional (3D) Bi2Se3 films to ~30 meV above the Dirac point and probe their low-energy electrodynamic response in the presence of magnetic fields with high-precision time-domain terahertz polarimetry. For fields higher than 5 tesla, we observed quantized Faraday and Kerr rotations, whereas the dc transport is still semiclassical. A nontrivial Berry's phase offset to these values gives evidence for axion electrodynamics and the topological magnetoelectric effect. The time structure used in these measurements allows a direct measure of the fine-structure constant based on a topological invariant of a solid-state system.
Chen, Xing; Moore, Justin E; Zekarias, Meserret; Jensen, Lasse
2015-11-10
The optical properties of metallic nanoparticles with nanometre dimensions exhibit features that cannot be described by classical electrodynamics. In this quantum size regime, the near-field properties are significantly modified and depend strongly on the geometric arrangements. However, simulating realistically sized systems while retaining the atomistic description remains computationally intractable for fully quantum mechanical approaches. Here we introduce an atomistic electrodynamics model where the traditional description of nanoparticles in terms of a macroscopic homogenous dielectric constant is replaced by an atomic representation with dielectric properties that depend on the local chemical environment. This model provides a unified description of bare and ligand-coated nanoparticles, as well as strongly interacting nanoparticle dimer systems. The non-local screening owing to an inhomogeneous ligand layer is shown to drastically modify the near-field properties. This will be important to consider in optimization of plasmonic nanostructures for near-field spectroscopy and sensing applications.
Classical electrodynamics with vacuum polarization: electron self-energy and radiation reaction
NASA Astrophysics Data System (ADS)
Blinder, S. M.
2001-04-01
The region very close to an electron ( r ⪅ r0 = e2/ mc2 ≈ 2.8 × 10 -13 cm) is, according to quantum electrodynamics, a seething maelstrom of virtual electron-positron pairs flashing in and out of existence. To take account of this well-established physical reality, a phenomenological representation for vacuum polarization is introduced into the framework of classical electrodynamics. Such a model enables a consistent picture of classical point charges with finite electromagnetic self-energy. It is further conjectured that the reaction of a point charge to its own electromagnetic field is tantamount to interaction with its vacuum polarization charge or "aura." This leads to a modification of the Lorentz-Dirac equation for the force on an accelerating electron, a new differential-difference equation which avoids the pathologies of preacceleration and runaway solutions.
Quantized Faraday and Kerr rotation and axion electrodynamics of a 3D topological insulator
NASA Astrophysics Data System (ADS)
Wu, Liang; Salehi, M.; Koirala, N.; Moon, J.; Oh, S.; Armitage, N. P.
2016-12-01
Topological insulators have been proposed to be best characterized as bulk magnetoelectric materials that show response functions quantized in terms of fundamental physical constants. Here, we lower the chemical potential of three-dimensional (3D) Bi2Se3 films to ~30 meV above the Dirac point and probe their low-energy electrodynamic response in the presence of magnetic fields with high-precision time-domain terahertz polarimetry. For fields higher than 5 tesla, we observed quantized Faraday and Kerr rotations, whereas the dc transport is still semiclassical. A nontrivial Berry’s phase offset to these values gives evidence for axion electrodynamics and the topological magnetoelectric effect. The time structure used in these measurements allows a direct measure of the fine-structure constant based on a topological invariant of a solid-state system.
NASA Astrophysics Data System (ADS)
Hendi, S. H.; Panahiyan, S.
2014-12-01
Motivated by the string corrections on the gravity and electrodynamics sides, we consider a quadratic Maxwell invariant term as a correction of the Maxwell Lagrangian to obtain exact solutions of higher dimensional topological black holes in Gauss-Bonnet gravity. We first investigate the asymptotically flat solutions and obtain conserved and thermodynamic quantities which satisfy the first law of thermodynamics. We also analyze thermodynamic stability of the solutions by calculating the heat capacity and the Hessian matrix. Then, we focus on horizon-flat solutions with an anti-de Sitter (AdS) asymptote and produce a rotating spacetime with a suitable transformation. In addition, we calculate the conserved and thermodynamic quantities for asymptotically AdS black branes which satisfy the first law of thermodynamics. Finally, we perform thermodynamic instability criterion to investigate the effects of nonlinear electrodynamics in canonical and grand canonical ensembles.
Numerical and Analytical Model of an Electrodynamic Dust Shield for Solar Panels on Mars
NASA Technical Reports Server (NTRS)
Calle, C. I.; Linell, B.; Chen, A.; Meyer, J.; Clements, S.; Mazumder, M. K.
2006-01-01
Masuda and collaborators at the University of Tokyo developed a method to confine and transport particles called the electric curtain in which a series of parallel electrodes connected to an AC source generates a traveling wave that acts as a contactless conveyor. The curtain electrodes can be excited by a single-phase or a multi-phase AC voltage. A multi-phase curtain produces a non-uniform traveling wave that provides controlled transport of those particles [1-6]. Multi-phase electric curtains from two to six phases have been developed and studied by several research groups [7-9]. We have developed an Electrodynamic Dust Shield prototype using threephase AC voltage electrodes to remove dust from surfaces. The purpose of the modeling work presented here is to research and to better understand the physics governing the electrodynamic shield, as well as to advance and to support the experimental dust shield research.
Quantum Zeno Effect in the Strong Measurement Regime of Circuit Quantum Electrodynamics
2016-05-17
New J. Phys. 18 (2016) 053031 doi:10.1088/1367-2630/18/5/053031 PAPER Quantum Zeno effect in the strongmeasurement regime of circuit quantum ...Keywords: quantumZeno effect, quantum jumps, superconducting qubit, circuit QED, random telegraph signals Abstract Weobserve the quantumZeno effect...where the act ofmeasurement slows the rate of quantum state transitions—in a superconducting qubit using linear circuit quantum electrodynamics readout
Holographic paramagnetism-ferromagnetism phase transition in the Born-Infeld electrodynamics
NASA Astrophysics Data System (ADS)
Wu, Ya-Bo; Zhang, Cheng-Yuan; Lu, Jun-Wang; Fan, Bi; Shu, Shuang; Liu, Yu-Chen
2016-09-01
In the probe limit, we investigate the effects of the Born-Infeld electrodynamics on the holographic paramagnetism-ferromagnetism phase transition in the background of a Schwarzschild-AdS black hole spacetime. We find that the presence of Born-Infeld scale parameter b decreases the critical temperature and makes the magnetic moment harder to form in the case of without external field. Furthermore, the increase of b will result in extending the period of the external magnetic field.
Desert Research and Technology Studies Exposure of Lotus Coated Electrodynamic Shield Samples
NASA Technical Reports Server (NTRS)
Rodriquez, Marcello; Peters, Wanda C.; Straka, Sharon A.; Jones, Craig B.
2011-01-01
The Lotus dust mitigation coating and the electrodynamic shield (EDS) are two new technologies currently being developed by NASA as countermeasures for addressing dust accumulation for long-duration human space exploration. These combined technologies were chosen by the Habitation Demonstration Unit (HDU) program for desert dust exposure at the Desert Research and Technologies Studies (D-RaTS) test site in Arizona. Characterization of these samples was performed prior to, during and post D-RaTS exposure.
Electrodynamics at non-zero temperature, chemical potential and Bose condensate
Dolgov, Alexander D.; Lepidi, Angela; Piccinelli, Gabriella E-mail: lepidi@fe.infn.it
2009-02-15
Electrodynamics of charged scalar bosons and spin 1/2 fermions is studied at non-zero temperature, chemical potentials, and possible Bose condensate of the charged scalars. Debye screening length, plasma frequency, and the photon dispersion relation are calculated. It is found that in presence of the condensate the time-time component of the photon polarization operator in the first order in electric charge squared acquires infrared singular parts proportional to inverse powers of the spatial photon momentum k.
Rodriguez, Justo
2008-10-01
A general expression for optical binding energy between particles of any size, in counterpropagating beams with and without interference, is derived using quantum electrodynamics. The effect of particle size on the optically induced interparticle energy surface, which has been the subject of recent research, is explored. Significant changes in this surface when particle size approaches the wavelength of the optical field are revealed. Finally, optically induced particle arrays that may be fabricated with these potentials are briefly discussed.
Photon antibunching and bunching in a ring-resonator waveguide quantum electrodynamics system.
Chen, Zihao; Zhou, Yao; Shen, Jung-Tsung
2016-07-15
We numerically investigate the photonic state generation and its nonclassical correlations in a ring-resonator waveguide quantum electrodynamics system. Specifically, we discuss photon antibunching and bunching in various scenarios, including the imperfect resonator with backscattering and dissipations. Our numerical results indicate that an imperfect ring resonator with backscattering can enhance the quality of antibunching. In addition, we also identify the quantum photonic halo phenomenon in the photon scattering dynamics and the shoulder effect in the second-order correlation function.
Gaigalas, Gediminas; Gaidamauskas, Erikas; Rudzikas, Zenonas; Magnani, Nicola; Caciuffo, Roberto
2010-02-15
Large-scale multiconfiguration Dirac-Fock calculations have been performed for the superheavy element eka-thorium, Z=122. The resulting atomic structure is compared with that obtained by various computational approaches involving different degrees of approximation in order to elucidate the role that correlation, relativistic, Breit, and quantum electrodynamics corrections play in determining the low-energy atomic spectrum. The accuracy of the calculations is assessed by comparing theoretical results obtained for thorium with available experimental data.
Second entanglement and (re)Born wave functions in Stochastic Electrodynamics
NASA Astrophysics Data System (ADS)
Kracklauer, A. F.
2006-01-01
The wave function in Quantum Mechanics has properties that render its physical interpretation unclear. On the one hand, its modulus squared is interpreted as a probability density, but, unlike conventional probabilities, it interacts with the material world. In addition, it is thought to have encapsulated nonlocal correlation and, according to modern thought, parallel information in a manner impossible according to classical physics. In this paper, an extended version of Stochastic Electrodynamics is presented which offers conventional models for these otherwise spooky features.
Electrodynamic Tether Operations beyond the Ionosphere in the Low-Density Magnetosphere
NASA Technical Reports Server (NTRS)
Stone, Nobie H.
2007-01-01
In the classical concept for the operation of electrodynamic tethers in space, a voltage is generated across the tether, either by the tether's orbital motion through the earth's planetary magnetic field or by a power supply; electrons are then collected from the ionospheric plasma at the positive pole; actively emitted back into space at the negative pole; and the circuit is closed by currents driven through the ambient conducting ionosphere. This concept has been proven to work in space by the Tethered Satellite System TSS-1 and TSS-1R Space Shuttle missions; and the Plasma Motor-Generator (PMG) tether flight experiment. However, it limits electrodynamic tether operations to the F-region of the ionosphere where the plasma density is sufficient to conduct the required currents--in other words, between altitudes of approximately 200 to 1000 km in sunlight. In the earth's shadow, the ionospheric density drops precipitously and tether operations, using the above approach, are not effective--even within this altitude range. There are numerous missions that require in-space propulsion in the Earth's shadow and/or outside of the above altitude range. This paper will, therefore, present the fundamentals of a concept that would allow electrodynamic tethers to operate almost anywhere within the magnetosphere, the region of space containing the earth's planetary magnetic field. In other words, because operations would be virtually independent of any ambient plasma, the range of electrodynamic operations would be extended into the earth's shadow and out to synchronous orbit--forty times the present operational range. The key to this concept is the active generation of plasma at each pole of the tether so that current generation ,does not depend on the conductivity of the ambient ionosphere. Arguments will be presented, based on ,existing flight data, which shed light on the behavior of charge emissions in space and show the plausibility of the concept.
Short wavelength quantum electrodynamical correction to cold plasma-wave propagation
Lundin, J.; Brodin, G.; Marklund, M.
2006-10-15
The effect of short wavelength quantum electrodynamic (QED) correction on plasma-wave propagation is investigated. The effect on plasma oscillations and on electromagnetic waves in an unmagnetized as well as a magnetized plasma is investigated. The effects of the short wavelength QED corrections are most evident for plasma oscillations and for extraordinary modes. In particular, the QED correction allow plasma oscillations to propagate, and the extraordinary mode loses its stop band. The significance of our results is discussed.
NASA Astrophysics Data System (ADS)
Di Rocco, Héctor O.; Lanzini, Fernando
2016-04-01
The correction to the Coulomb repulsion between two electrons due to the exchange of a transverse photon, referred to as the Breit interaction, as well as the main quantum electrodynamics contributions to the atomic energies (self-energy and vacuum polarization), are calculated using the recently formulated relativistic screened hydrogenic model. Comparison with the results of multiconfiguration Dirac-Hartree-Fock calculations and experimental X- ray energies is made.
NASA Astrophysics Data System (ADS)
Zessin, H.; Spies, P.; Mateu, L.
2016-11-01
In this study, we report a power management circuit for a combined piezoelectric- electrodynamic generator. A piezoelectric element is bonded to a spring steel cantilever beam and a magnet, used as tip mass, oscillates through a coil. This principle creates the combined generator. A test setup has been created to automate the characterization of the piezoelectric generator and its power management circuit. Three different power management circuits for the piezoelectric part of the combined generator have been analysed: a bridge rectifier, an SSHI circuit with an external inductance and an SSHI circuit which utilizes the coil of the electrodynamic generator as circuit element. The three circuits are compared in terms of their output power, efficiency and power density. The SSHI circuit with an external inductance has the highest output power and efficiency, followed by the SSHI circuit with the electrodynamic generator coil. The power density of the bridge rectifier is the highest but for higher efficiency the power density of the SSHI circuit with the coil of the electromagnetic generator reaches the best results.
Mapping Ionospheric Electrodynamics with SuperDARN Data: An Assimilative Technique
NASA Astrophysics Data System (ADS)
Cousins, E. D.; Matsuo, T.; Richmond, A. D.
2013-12-01
Mapping of electrodynamic parameters in Earth's high-latitude ionosphere has been performed widely for many years. Knowledge of the complete pattern of ionospheric plasma convection enables studies of solar wind-magnetosphere-ionosphere coupling, allows for the placing of localized observations in a larger context, and can be used to drive coupled ionosphere-thermosphere first-principles models. In the past, an assimilative procedure has been developed to map ionospheric electrodynamics based on combining various types of observations (e.g., magnetometers, satellites, and incoherent or coherent scatter radars) [Richmond and Kamide, 1988], and a simple regression technique has been developed to use exclusively data from the Super Dual Auroral Radar Network (SuperDARN) coherent backscatter radars [Ruohoniemi and Baker, 1998; Shepherd and Ruohoniemi, 2000]. In this study, an assimilative procedure is developed to combine exclusively SuperDARN data with the empirical plasma convection model of Cousins and Shepherd [2010] (CS10, also based on SuperDARN data). The statistical properties of the CS10 model errors are investigated using the method of empirical orthogonal functions (EOFs) applied to an ~2 yr data set, and a parameterization of the CS10 model error covariance matrix is obtained. The new SuperDARN assimilative procedure, which takes into account realistic error covariances, is shown to significantly improve the mapping of electrodynamic parameters (as compared to the existing regression-based SuperDARN mapping procedure). The application of this assimilative procedure is demonstrated for a geomagnetic storm.
From the Rocket Equation to Maxwell's Equations: Electrodynamic Tether Propulsion Nears Space Test
NASA Technical Reports Server (NTRS)
Johnson, Les; Estes, Robert
1999-01-01
The US space program is facing a growing challenge to its decades-long, global leadership position, as current launch costs consume valuable resources and limit achievements in science, exploration, and commercial development. More than 40% of projected launches over the next 10 years have payloads with intended destinations beyond low-Earth orbit. Therefore, more cost-effective upper stages and on-board propulsion systems are critical elements in reducing total space transportation costs. A new type of space propulsion, using electrodynamic tethers, may be capable of performing multiple sequential missions without resupply and have a potential usable lifetime of several years. They may provide an in-space infrastructure that has a very low life cycle cost and greatly enhanced mission flexibility, thus supporting the goal of reducing the cost of access to space. Electrodynamic tether thrusters work by virtue of the force the Earth's magnetic field exerts on a wire carrying an electrical current. The effect is the basis for electric motors and generators. The Propulsive Small Expendable Deployer System (ProSEDS) experiment, planned for launch in the summer of 2000, will demonstrate the use electrodynamic tether thrust by lowering the altitude of a Delta-H rocket's upper stage on which it will be flying. Applications of the technology include a passive deorbit system for spacecraft at their end-of-life, reusable Orbit Transfer Vehicles, propellantless reboost of the International Space Station, and propulsion and power generation for future missions to Jupiter.
Shock wave polarizations and optical metrics in the Born and the Born–Infeld electrodynamics
Minz, Christoph; Borzeszkowski, Horst-Heino von; Chrobok, Thoralf; Schellstede, Gerold
2016-01-15
We analyze the behavior of shock waves in nonlinear theories of electrodynamics. For this, by use of generalized Hadamard step functions of increasing order, the electromagnetic potential is developed in a series expansion near the shock wave front. This brings about a corresponding expansion of the respective electromagnetic field equations which allows for deriving relations that determine the jump coefficients in the expansion series of the potential. We compute the components of a suitable gauge-normalized version of the jump coefficients given for a prescribed tetrad compatible with the shock front foliation. The solution of the first-order jump relations shows that, in contrast to linear Maxwell’s electrodynamics, in general the propagation of shock waves in nonlinear theories is governed by optical metrics and polarization conditions describing the propagation of two differently polarized waves (leading to a possible appearance of birefringence). In detail, shock waves are analyzed in the Born and Born–Infeld theories verifying that the Born–Infeld model exhibits no birefringence and the Born model does. The obtained results are compared to those ones found in literature. New results for the polarization of the two different waves are derived for Born-type electrodynamics.
Electrodynamic Dust Shield for Surface Exploration Activities on the Moon and Mars
NASA Technical Reports Server (NTRS)
Calle, C. I.; Immer, C. D.; Clements, J. S.; Chen, A.; Buhler, C. R.; Lundeen, P.; Mantovani, J. G.; Starnes, J. W.; Michalenko, M.; Mazumder, M. K.
2006-01-01
The Apollo missions to the moon showed that lunar dust can hamper astronaut surface activities due to its ability to cling to most surfaces. NASA's Mars exploration landers and rovers have also shown that the problem is equally hard if not harder on Mars. In this paper, we report on our efforts to develop and electrodynamic dust shield to prevent the accumulation of dust on surfaces and to remove dust already adhering to those surfaces. The parent technology for the electrodynamic dust shield, developed in the 1970s, has been shown to lift and transport charged and uncharged particles using electrostatic and dielectrophoretic forces. This technology has never been applied for space applications on Mars or the moon due to electrostatic breakdown concerns. In this paper, we show that an appropriate design can prevent the electrostatic breakdown at the low Martian atmospheric pressures. We are also able to show that uncharged dust can be lifted and removed from surfaces under simulated Martian environmental conditions. This technology has many potential benefits for removing dust from visors, viewports and many other surfaces as well as from solar arrays. We have also been able to develop a version of the electrodynamic dust shield working under. hard vacuum conditions. This version should work well on the moon.
Plasmon-coupled resonance energy transfer: A real-time electrodynamics approach
NASA Astrophysics Data System (ADS)
Ding, Wendu; Hsu, Liang-Yan; Schatz, George C.
2017-02-01
This paper presents a new real-time electrodynamics approach for determining the rate of resonance energy transfer (RET) between two molecules in the presence of plasmonic or other nanostructures (inhomogeneous absorbing and dispersive media). In this approach to plasmon-coupled resonance energy transfer (PC-RET), we develop a classical electrodynamics expression for the energy transfer matrix element which is evaluated using the finite-difference time-domain (FDTD) method to solve Maxwell's equations for the electric field generated by the molecular donor and evaluated at the position of the molecular acceptor. We demonstrate that this approach yields RET rates in homogeneous media that are in precise agreement with analytical theory based on quantum electrodynamics (QED). In the presence of gold nanoparticles, our theory shows that the long-range decay of the RET rates can be significantly modified by plasmon excitation, with rates increased by as much as a factor of 106 leading to energy transfer rates over hundreds of nm that are comparable to that over tens of nm in the absence of the nanoparticles. These promising results suggest important future applications of the PC-RET in areas involving light harvesting or sensing, where energy transfer processes involving inhomogeneous absorbing and dispersive media are commonplace.
NASA Astrophysics Data System (ADS)
Zangeneh, M. Kord; Dehyadegari, A.; Sheykhi, A.; Dehghani, M. H.
2016-03-01
In this paper, we construct a new class of topological black hole Lifshitz solutions in the presence of nonlinear exponential electrodynamics for Einstein-dilaton gravity. We show that the reality of Lifshitz supporting Maxwell matter fields exclude the negative horizon curvature solutions except for the asymptotic AdS case. Calculating the conserved and thermodynamical quantities, we obtain a Smarr type formula for the mass and confirm that thermodynamics first law is satisfied on the black hole horizon. Afterward, we study the thermal stability of our solutions and figure out the effects of different parameters on the stability of solutions under thermal perturbations. Next, we apply the gauge/gravity duality in order to calculate the ratio of shear viscosity to entropy for a three-dimensional hydrodynamic system by using the pole method. Furthermore, we study the behavior of holographic conductivity for two-dimensional systems such as graphene. We consider linear Maxwell and nonlinear exponential electrodynamics separately and disclose the effect of nonlinearity on holographic conductivity. We indicate that holographic conductivity vanishes for z > 3 in the case of nonlinear electrodynamics while it does not in the linear Maxwell case. Finally, we solve perturbative additional field equations numerically and plot the behaviors of real and imaginary parts of conductivity for asymptotic AdS and Lifshitz cases. We present experimental results match with our numerical ones.
NASA Technical Reports Server (NTRS)
Kaeppler, S. R.; Kletzing, C. A.; Bounds, S. R.; Gjerloev, J. W.; Anderson, B. J.; Korth, H.; LaBelle, J. W.; Dombrowski, M. P.; Lessard, M.; Pfaff, R. F.; Rowland, D. E.; Jones, S.; Heinselman, C. J.
2011-01-01
The Auroral Current and Electrodynamics Structure (ACES) mission consisted of two sounding rockets launched nearly simultaneously from Poker Flat Research Range, AK on January 29, 2009 into a dynamic multiple-arc aurora. The ACES rocket mission was designed to observe electrodynamic and plasma parameters above and within the current closure region of the auroral ionosphere. Two well instrumented payloads were flown along very similar magnetic field footprints, at different altitudes, with small temporal separation between both payloads. The higher altitude payload (apogee 360 km), obtained in-situ measurements of electrodynamic and plasma parameters above the current closure region to determine the input signature. The low altitude payload (apogee 130 km), made similar observations within the current closure region. Results are presented comparing observations of the electric fields, magnetic components, and the differential electron energy flux at magnetic footpoints common to both payloads. In situ data is compared to the ground based all-sky imager data, which presents the evolution of the auroral event as the payloads traversed through magnetically similar regions. Current measurements derived from the magnetometers on the high altitude payload observed upward and downward field-aligned currents. The effect of collisions with the neutral atmosphere is investigated to determine it is a significant mechanism to explain discrepancies in the low energy electron flux. The high altitude payload also observed time-dispersed arrivals in the electron flux and perturbations in the electric and magnetic field components, which are indicative of Alfven waves.
NASA Technical Reports Server (NTRS)
Kaeppler, S. R.; Kletzing, C. A.; Bounds, S. R.; Gjerloev, J. W.; Anderson, B. J.; Korth, H.; LaBelle, J. W.; Dombrowski, M. P.; Lessard, M.; Pfaff, R. F.; Rowland D. E.; Jones, S.; Heinselman, C. J.
2012-01-01
The Auroral Current and Electrodynamics Structure (ACES) mission consisted of two sounding rockets launched nearly simultaneously from Poker Flat Research Range, AK on January 29, 2009 into a dynamic multiple-arc aurora. The ACES rocket mission was designed to observe electrodynamic and plasma parameters above and within the current closure region of the auroral ionosphere. Two well instrumented payloads were flown along very similar magnetic field footprints, at different altitudes, with small temporal separation between both payloads. The higher altitude payload (apogee 360 km), obtained in-situ measurements of electrodynamic and plasma parameters above the current closure region to determine the input signature. The low altitude payload (apogee 130 km), made similar observations within the current closure region. Results are presented comparing observations of the electric fields, magnetic components, and the differential electron energy flux at magnetic footpoints common to both payloads. In situ data is compared to the ground based all-sky imager data, which presents the evolution of the auroral event as the payloads traversed through magnetically similar regions. Current measurements derived from the magnetometers on the high altitude payload observed upward and downward field-aligned currents. The effect of collisions with the neutral atmosphere is investigated to determine if it is a significant mechanism to explain discrepancies in the low energy electron flux. The high altitude payload also observed time-dispersed arrivals in the electron flux and perturbations in the electric and magnetic field components, which are indicative of Alfven waves.