SCUBA: A Camera for the James Clerk Maxwell Telescope
Gear, W. K.; Cunningham, C. R.
We briefly describe the Submillimetre Common User Bolometer Array which has been built and is currently being tested at Edinburgh for the James Clerk Maxwell Telescope in Hawaii. This instrument will define the state-of-the-art in submillimetre continuum astronomical instrumentation. SCUBA has 2 arrays covering a field of two and a half arcminutes simultaneously in 2 submillimetre bands, plus 3 longer wavelength individual pixels for photometry. The detectors are germanium bolometers cooled to 0.1K with a dilution fridge and all pixels are background-limited.
HARP/ACSIS: A submillimetre spectral imaging system on the James Clerk Maxwell Telescope
Buckle, J V; Smith, H; Dent, W R F; Bell, G; Curtis, E I; Dace, R; Gibson, H; Graves, S F; Leech, J; Richer, J S; Williamson, R; Withington, S; Yassin, G; Bennett, R; Hastings, P; Laidlaw, I; Lightfoot, J F; Burgess, T; Dewdney, P E; Hovey, G; Willis, A G; Redman, R; Wooff, B; Berry, D S; Cavanagh, B; Davis, G R; Dempsey, J; Friberg, P; Jenness, T; Kackley, R; Rees, N P; Tilanus, R; Walther, C; Zwart, W; Klapwijk, T M; Kroug, M; Zijlstra, T
2009-01-01
This paper describes a new Heterodyne Array Receiver Programme (HARP) and Auto-Correlation Spectral Imaging System (ACSIS) that have recently been installed and commissioned on the James Clerk Maxwell Telescope (JCMT). The 16-element focal-plane array receiver, operating in the submillimetre from 325 to 375 GHz, offers high (three-dimensional) mapping speeds, along with significant improvements over single-detector counterparts in calibration and image quality. Receiver temperatures are $\\sim$120 K across the whole band and system temperatures of $\\sim$300K are reached routinely under good weather conditions. The system includes a single-sideband filter so these are SSB figures. Used in conjunction with ACSIS, the system can produce large-scale maps rapidly, in one or more frequency settings, at high spatial and spectral resolution. Fully-sampled maps of size 1 square degree can be observed in under 1 hour. The scientific need for array receivers arises from the requirement for programmes to study samples of ...
Jenness, Tim; Tilanus, Remo P J; Cavanagh, Brad; Berry, David S; Leech, Jamie; Rizzi, Luca
2015-01-01
With the advent of modern multi-detector heterodyne instruments that can result in observations generating thousands of spectra per minute it is no longer feasible to reduce these data as individual spectra. We describe the automated data reduction procedure used to generate baselined data cubes from heterodyne data obtained at the James Clerk Maxwell Telescope. The system can automatically detect baseline regions in spectra and automatically determine regridding parameters, all without input from a user. Additionally it can detect and remove spectra suffering from transient interference effects or anomalous baselines. The pipeline is written as a set of recipes using the ORAC-DR pipeline environment with the algorithmic code using Starlink software packages and infrastructure. The algorithms presented here can be applied to other heterodyne array instruments and have been applied to data from historical JCMT heterodyne instrumentation.
The James Clerk Maxwell Telescope Legacy Survey of Nearby Star-forming Regions in the Gould Belt
Ward-Thompson, D; Hatchell, J; Hogerheijde, M R; Bastien, P; Basu, S; Bonnell, I; Bowey, J; Brunt, C; Buckle, J; Butner, H; Cavanagh, B; Chrysostomou, A; Curtis, E; Davis, C J; Dent, W R F; van Dishoeck, E; Edmunds, M G; Fich, M; Fiege, J; Fissel, L; Friberg, P; Friesen, R; Frieswijk, W; Fuller, G A; Gosling, A; Graves, S; Greaves, J S; Helmich, F; Hills, R E; Holland, W S; Houde, M; Jayawardhana, R; Johnstone, D; Joncas, G; Kirk, H; Kirk, J M; Knee, L B G; Matthews, B; Matthews, H; Matzner, C; Moriarty-Schieven, G H; Naylor, D; Nutter, D; Padman, R; Plume, R; Rawlings, J M C; Redman, R O; Reid, M; Richer, J S; Shipman, R; Simpson, R J; Spaans, M; Stamatellos, D; Tsanis, Y; Viti, S; Weferling, B; White, G J; Whitworth, A P; Wouterloot, J; Yates, J; Zhu, M
2007-01-01
This paper describes a James Clerk Maxwell Telescope (JCMT) legacy survey that has been awarded roughly 500 hrs of observing time to be carried out from 2007 to 2009. In this survey we will map with SCUBA-2 (Submillimetre Common User Bolometer Array 2) almost all of the well-known low-mass and intermediate-mass star-forming regions within 0.5 kpc that are accessible from the JCMT. Most of these locations are associated with the Gould Belt. From these observations we will produce a flux-limited snapshot of star formation near the Sun, providing a legacy of images, as well as point-source and extended-source catalogues, over almost 700 square degrees of sky. The resulting images will yield the first catalogue of prestellar and protostellar sources selected by submillimetre continuum emission, and should increase the number of known sources by more than an order of magnitude. We will also obtain CO maps with the array receiver HARP (Heterodyne Array Receiver Programme), in three CO isotopologues, of a large typi...
We present large-area maps of the CO J = 3-2 emission obtained at the James Clerk Maxwell Telescope for four spiral galaxies in the Virgo Cluster. We combine these data with published CO J = 1-0, 24 μm, and Hα images to measure the CO line ratios, molecular gas masses, and instantaneous gas depletion times. For three galaxies in our sample (NGC 4254, NGC 4321, and NGC 4569), we obtain molecular gas masses of 7 x 108 - 3 x 109 M sun and disk-averaged instantaneous gas depletion times of 1.1-1.7 Gyr. We argue that the CO J = 3-2 line is a better tracer of the dense star-forming molecular gas than the CO J = 1-0 line, as it shows a better correlation with the star formation rate surface density both within and between galaxies. NGC 4254 appears to have a larger star formation efficiency (smaller gas depletion time), perhaps because it is on its first passage through the Virgo Cluster. NGC 4569 shows a large-scale gradient in the gas properties traced by the CO J = 3-2/J = 1-0 line ratio, which suggests that its interaction with the intracluster medium is affecting the dense star-forming portion of the interstellar medium directly. The fourth galaxy in our sample, NGC 4579, has weak CO J = 3-2 emission despite having bright 24 μm emission; however, much of the central luminosity in this galaxy may be due to the presence of a central active galactic nucleus.
Tan, Boon-Kok; Rigopoulou, D; Warren, B E; Wilson, C D; Attewell, D; Azimlu, M; Bendo, G J; Butner, H M; Brinks, E; Chanial, P; Clements, D L; Heesen, V; Israel, F; Knapen, J H; Matthews, H E; Mortier, A M J; Mühle,; Sánchez-Gallego, J R; Tilanus, R P J; Usero, A; van der Werf, P; Zhu, M
2013-01-01
We present $^{12}$CO \\textit{J=3$\\rightarrow$2} maps of NGC 2976 and NGC 3351 obtained with the James Clerk Maxwell Telescope (JCMT), both early targets of the JCMT Nearby Galaxy Legacy Survey (NGLS). We combine the present observations with $^{12}$CO \\textit{J=1$\\rightarrow$0} data and find that the computed $^{12}$CO \\textit{J=3$\\rightarrow$2} to $^{12}$CO \\textit{J=1$\\rightarrow$0} line ratio ($R_{31}$) agrees with values measured in other NGLS field galaxies. We compute the M$_{\\rm{H_2}}$ value and find that it is robust against the value of $R_{31}$ used. Using \\textsc{Hi} data from the The \\textsc{Hi} Nearby Galaxy Survey (THINGS) survey, we find a tight correlation between surface density of H$_2$ and star formation rate density for NGC 3351 when $^{12}$CO \\textit{J=3$\\rightarrow$2} data are used. Finally, we compare the $^{12}$CO \\textit{J=3$\\rightarrow$2} intensity with the PAH 8 $\\mu$m surface brightness and find a good correlation in the high surface brightness regions. We extend this study to incl...
James Clerk Maxwell: Life and science
Marston, Philip L.
2016-07-01
Maxwell's life and science are presented with an account of the progression of Maxwell's research on electromagnetic theory. This is appropriate for the International Year of Light and Light-based Technologies, 2015. Maxwell's own confidence in his 1865 electromagnetic theory of light is examined, along with some of the difficulties he faced and the difficulties faced by some of his followers. Maxwell's interest in radiation pressure and electromagnetic stress is addressed, as well as subsequent developments. Some of Maxwell's other contributions to physics are discussed with an emphasis on the kinetic and molecular theory of gases. Maxwell's theistic perspective on science is illustrated, accompanied by examples of perspectives on Maxwell and his science provided by his peers and accounts of his interactions with those peers. Appendices examine the peer review of Maxwell's 1865 electromagnetic theory paper and the naming of the Maxwell Garnett effective media approximation and provide various supplemental perspectives. From Maxwell's publications and correspondence there is evidence he had a high regard for Michael Faraday. Examples of Maxwell's contributions to electromagnetic terminology are noted.
Earlier this year saw the centenary of the birth of Albert Einstein. It is highly apt that 1979, which has been marked by further consolidation of the unified theory of weak and electromagnetic interactions and its recognition in the award of the Nobel Prize to Glashow, Salam and Weinberg, is also the centenary of the death of the great Scottish physicist who first formulated a unified theory of electric and magnetic fields. We are grateful to Abdus Salam for drawing our attention to the Maxwell anniversary
James Clerk Maxwell's class of 1856/57
Reid, John S.
2015-01-01
James Clerk Maxwell is known for his outstanding contributions to fundamental physics. These include providing the equations that govern electric and magnetic fields, establishing the basis of modern colourimetry, finding important relationships in thermodynamics, molecular science, mechanics, optics and astronomy. In his first Professorial chair in 1856 at the Marischal College and University of Aberdeen he undertook a substantial amount of teaching that laid the foundation for his later ped...
James Clerk Maxwell perspectives on his life and work
McCartney, Mark; Whitaker, Andrew
2014-01-01
James Clerk Maxwell (1831-1879) had a relatively brief, but remarkable life, lived in his beloved rural home of Glenlair, and variously in Edinburgh, Aberdeen, London and Cambridge. His scholarship also ranged wide - covering all the major aspects of Victorian natural philosophy. He was one of the most important mathematical physicists of all time, coming only after Newton and Einstein. In scientific terms his immortality is enshrined in electromagnetism and Maxwell's equations, but as this book shows, there was much more to Maxwell than electromagnetism, both in terms of his science and his wider life. Maxwell's life and contributions to science are so rich that they demand the expertise of a range of academics - physicists, mathematicians, and historians of science and literature - to do him justice. The various chapters will enable Maxwell to be seen from a range of perspectives. Chapters 1 to 4 deal with wider aspects of his life in time and place, at Aberdeen, King's College London and the Cavendish Labo...
James Clerk Maxwell's class of 1856/57
Reid, John S
2015-01-01
James Clerk Maxwell is known for his outstanding contributions to fundamental physics. These include providing the equations that govern electric and magnetic fields, establishing the basis of modern colourimetry, finding important relationships in thermodynamics, molecular science, mechanics, optics and astronomy. In his first Professorial chair in 1856 at the Marischal College and University of Aberdeen he undertook a substantial amount of teaching that laid the foundation for his later pedagogic output. This paper examines whom he taught, where his first students came from and what they did in later life, drawing material from a privately published memoir. Thumbnail portraits are included for 70% of his class. The analysis complements the usual emphasis on educational method and content. The data provide an interesting sociological survey of what Scottish University education was achieving in the middle of the 19th century and is presented as raw material for a wider enquiry.
The electric theories of J. Clerk Maxwell a historical and critical study
Duhem, Pierre Maurice Marie
2015-01-01
In this volume Pierre Duhem first gives an overview of 19th century electricity and magnetism. Next, he applies his keen historical, philosophical, and physical intuition to critiquing Maxwell's theories, especially his electromagnetic theory of light and the ad hoc introduction of displacement current, which he considers too much a product of the "esprit de géométrie" than the "esprit de finesse," as Pascal calls it. In this book, Duhem is guided by the principle that a theory that offers contradictions, even if the theory is posed by a genius, needs to be analysed and discussed until a c
Qadir, Asghar; Mason, D. P.
2015-04-01
James Clerk Maxwell is generally regarded as the greatest contributor to the development of Physics in the time between Newton and Einstein. His most important contributions are the Kinetic Theory of Gases and Electromagnetism which is the unified theory of Electricity and Magnetism. Although his major work on Electromagnetism was published in 1865 it was read at a meeting of the Royal Society of London in 1864. The sesquicentennial of the theory correctly falls in 2014. In this article that event is celebrated. Parts of his early and professional life are described. Aspects of his many contributions are discussed but mainly we concentrate on his contributions through thermal and electromagnetic Physics.
The Scientific Papers of James Clerk Maxwell
Clerk Maxwell, James; Niven, W. D.
2011-01-01
27. On the viscosity or internal friction of air and other gases; 28. On the dynamical theory of gases; 29. On the theory of the maintenance of electric currents by mechanical work without the use of permanent magnets; 30. On the equilibrium of a spherical envelope; 31. On the best arrangement for producing a pure spectrum on a screen; 32. The construction of stereograms of surfaces; 33. On reciprocal diagrams in space and their relation to Airy's function of stress; 34. On governors; 35. Experiment in magneto-electric induction; 36. On a method of making a direct comparison of electrostatic with electromagnetic force; 37. On the cyclide; 38. On a bow seen on the surface of ice; 39. On reciprocal figures, frames, and diagrams of forces; 40. On the displacement in a case of fluid motion; 41. Address to the mathematical and physical sections of the British Association, 1870; 42. On colour-vision at different points of the retina; 43. On hills and dales; 44. Introductory lecture on experimental physics; 45. On the solution of electrical problems by the transformation of conjugate functions; 46. On the mathematical classification of physical quantities; 47. On colour vision; 48. On the geometrical mean distance of two figures on a plane; 49. On the induction of electric currents in an infinite plane sheet of uniform conductivity; 50. On the condition that, in the transformation of any figure by curvilinear co-ordinates in three dimensions, every angle in the new figure shall be equal to the corresponding angle in the original figure; 51. Reprint of Papers on electrostatics and magnetism. By Sir W. Thomson. (Review); 52. On the proof of the equations of motion of a connected system; 53. On a problem in the calculus of variations in which the solution is discontinuous; 54. On action at a distance; 55. Elements of natural philosophy. By Sir W. Thomson and P. G. Tait. (Review); 56. On the theory of a system of electrified conductors, and other physical theories involving homogeneous quadratic functions; 57. On the focal lines of a refracted pencil; 58. An Essay on the mathematical principles of physics. By Rev. James Challis. (Review); 59. On Loschmidt's experiments on diffusion in relation to the kinetic theory of gases; 60. On the final state of a system of molecules in motion subject to forces of any kind; 61. Faraday; 62. Molecules (a lecture); 63. On double refraction in a viscous fluid in motion; 64. On Hamilton's characteristic function for a narrow beam of light; 65. On the relation of geometrical optics to other parts of mathematics and physics; 66. Plateau on soap-bubbles (Review); 67. Grove's Correlation of physical forces (Review); 68. On the application of Kirchhoff's rules for electric circuits to the solution of a geometric problem; 69. Van der Waals on the continuity of the gaseous and liquid states; 70. On the centre of motion of the eye; 71. On the dynamical evidence of the molecular constitution of bodies (a lecture); 72. On the application of Hamilton's characteristic function to the theory of an optical instrument symmetrical about its axis; 73. Atom; 74. Attraction; 75. On Bow's method of drawing diagrams in graphical statics with illustrations from Peaucellier's Linkage; 76. On the equilibrium of heterogeneous substances; 77. Diffusion of gases through absorbing substances; 78. General considerations concerning scientific apparatus; 79. Instruments connected with fluids; 80. Whewell's Writing and correspondence (Review); 81. On Ohm's Law; 82. On the protection of buildings from lightning; 83. Capillary action; 84. Hermann Ludwig Ferdinand Helmholtz; 85. On a paradox in the theory of attraction; 86. On approximate multiple integration between limits by summation; 87. On the unpublished electrical papers of the Hon. Henry Cavendish; 88. Constitution of bodies; 89. Diffusion; 90. Diagrams; 91. Tait's Thermo
2013-02-06
... determination was published in the Federal Register on January 10, 2013 (78 FR 2290). The initial investigation... Employment and Training Administration Verizon Services Corporation, Customer Services Clerk, General Clerk... of Verizon Services Corporation, Customer Services Clerk, General Clerk, Clarksburg, West...
2013-05-30
... Employment and Training Administration Verizon Services Corporation, Customer Service Clerk, General Clerk... workers and former workers of Verizon Services Corporation, Customer Service Clerk, General Clerk... February 6, 2013 (78 FR 8589). Pursuant to 29 CFR 90.18(c), reconsideration may be granted under...
Eisenberg, Bob
2016-01-01
Charges are everywhere because most atoms are charged. Chemical bonds are formed by electrons with their charge. Charges move and interact according to Maxwell's equations in space and in atoms where the equations of electrodynamics are embedded in Schroedinger's equation as the potential. Maxwell's equations are universal, valid inside atoms and between stars from times much shorter than those of atomic motion (0.1 femtoseconds) to years (32 mega-seconds). Maxwell's equations enforce the conservation of current. Analysis shows that the electric field can take on whatever value is needed to ensure conservation of current. The properties of matter rearrange themselves to satisfy Maxwell's equations and conservation of current. Conservation of current is as universal as Maxwell's equations themselves. Yet equations of electrodynamics find little place in the literature of material physics, chemistry, or biochemistry. Kinetic models of chemistry and Markov treatments of atomic motion are ordinary differential eq...
Kinsler, Paul; Thio, Timothy C Y; Trant, Claire; Kandapper, Navin
2012-01-01
Most of us will have at some time thrown a pebble into water, and watched the ripples spread outwards and fade away. But now there is a way to reverse the process, and make those ripples turn around and reconverge again, ... and again, and again. To do this we have designed the Maxwell's Fishpond, a water wave or "Tranformation Aquatics" version of the Maxwell's Fisheye lens [Tyc et al. 2011, Luneberg 1964] that is now well-known from transformation optics. These are transformation devices where wave propagation on the surface of a sphere is not modelled on an actual sphere, but in a flat device with carefully designed spatially varying properties. And just as for rays from a point source on a sphere, a wave disturbance in a Maxwell's Fisheye or Fishpond spreads out at first, but then reforms itself at its opposing point in the device. Here we show how such a device can be made for water waves, partly in friendly competition with comparable electromagnetic devices [Ma et al. 2011] and partly as an accessible ...
Cashier/Accounts Receivable Clerk Exploration.
Portsmouth City School Board, VA.
The student materials present exercises designed to simulate the job performed by a cashier/accounts receivable clerk. The content of the course covers job instructions, writing receipts, proving cash, customer accounts, preparing statements, and schedule of accounts receivable. Also included in the document are a pretest and post test for the…
An Analysis of the Payroll Clerking Occupation.
Peal, Sharyn; Rose, Virginia
The general purpose of the occupational analysis is to provide workable, basic information dealing with the many and varied duties performed in the payroll clerk occupation. The document opens with a brief introduction followed by a job description. The bulk of the document is presented in table form. Ten duties are broken down into a number of…
The contributions of Faraday and Maxwell to electrical science
Tricker, R A R
1966-01-01
The Contributions of Faraday and Maxwell to Electrical Science deals with the development of electromagnetic theory following the establishment of the basis for the first law of circulation relating to the magnetic fields generated by steady currents. This book is organized into two parts encompassing nine chapters that specifically treat the provision of the basis for the second law of circulation, the law that deals with the induction of currents, which was predominantly the work of British physicists, Michael Faraday and James Clerk Maxwell. Part I highlights their life, career, and contri
Maxwell: A new vision of the world
Maystre, Daniel
2014-05-01
The paper outlines the crucial contributions of James Clerk Maxwell to Physics and more generally to our vision of the world. He achieved 150 years ago a synthesis of the pioneering works in magnetostatics, electrostatics, induction and, by introducing the notion of displacement current, gave birth to Electromagnetics. Then, he deduced the existence of electromagnetic waves and identified light as one of them. Maxwell equations deeply changed a Newtonian conception of the world based on particle interactions by pointing out the vital role of waves in physics. This new conception had a strong influence on the development of quantum physics. Finally, the invariance of light velocity in Galilean frames led to Lorentz transformations, a key step toward the theory of relativity. Par ailleurs, les équations de Maxwell ont profondément changé une conception du monde newtonienne basée sur l'interaction entre particules en révélant le rôle essentiel des ondes en physique, ce qui eut une influence déterminante sur le développement de la physique quantique. Enfin, l'invariance de la vitesse de la lumière dans les repères galiléens a entraîné la découverte des transformations de Lorentz, une étape capitale vers la théorie de la relativité.
RESOLVING THE INNER JET STRUCTURE OF 1924-292 WITH THE EVENT HORIZON TELESCOPE
Lu Rusen; Fish, Vincent L.; Doeleman, Sheperd S. [Massachusetts Institute of Technology, Haystack Observatory, Route 40, Westford, MA 01886 (United States); Weintroub, Jonathan; Moran, James M.; Primiani, Rurik; Young, Ken H. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Bower, Geoffrey C.; Plambeck, Richard; Wright, Melvyn [Department of Astronomy, Radio Astronomy Laboratory, University of California Berkeley, 601 Campbell Hall, Berkeley, CA 94720-3411 (United States); Freund, Robert; Marrone, Daniel P. [Arizona Radio Observatory, Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721-0065 (United States); Friberg, Per; Tilanus, Remo P. J. [James Clerk Maxwell Telescope, Joint Astronomy Centre, 660 North A' ohoku Place, University Park, Hilo, HI 96720 (United States); Ho, Paul T. P.; Inoue, Makoto [Institute of Astronomy and Astrophysics, Academia Sinica, P.O. Box 23-141, Taipei 10617, Taiwan (China); Honma, Mareki; Oyama, Tomoaki [National Astronomical Observatory of Japan, Osawa 2-21-1, Mitaka, Tokyo 181-8588 (Japan); Krichbaum, Thomas P. [Max-Planck-Institut fuer Radioastronomie, Auf dem Huegel 69, D-53121 Bonn (Germany); Shen Zhiqiang, E-mail: rslu@haystack.mit.edu [Key Laboratory for Research in Galaxies and Cosmology, Shanghai Astronomical Observatory, Chinese Academy of Sciences, 80 Nandan Road, Shanghai 200030 (China); and others
2012-09-20
We present the first 1.3 mm (230 GHz) very long baseline interferometry model image of an active galactic nucleus (AGN) jet using closure phase techniques with a four-element array. The model image of the quasar 1924-292 was obtained with four telescopes at three observatories: the James Clerk Maxwell Telescope on Mauna Kea in Hawaii, the Arizona Radio Observatory's Submillimeter Telescope in Arizona, and two telescopes of the Combined Array for Research in Millimeter-wave Astronomy in California in 2009 April. With the greatly improved resolution compared with previous observations and robust closure phase measurement, the inner jet structure of 1924-292 was spatially resolved. The inner jet extends to the northwest along a position angle of -53 Degree-Sign at a distance of 0.38 mas from the tentatively identified core, in agreement with the inner jet structure inferred from lower frequencies, and making a position angle difference of {approx}80 Degree-Sign with respect to the centimeter jet. The size of the compact core is 0.15 pc with a brightness temperature of 1.2 Multiplication-Sign 10{sup 11} K. Compared with those measured at lower frequencies, the low brightness temperature may argue in favor of the decelerating jet model or particle-cascade models. The successful measurement of closure phase paves the way for imaging and time resolving Sgr A* and nearby AGNs with the Event Horizon Telescope.
Falconer, Isobel
2016-01-01
In 1877 James Clerk Maxwell and his student Donald McAlister refined Henry Cavendish's 1773 null experiment demonstrating the absence of electric charge inside a charged conductor. Such absence of charge was a mathematical prediction of the inverse square law, and both Cavendish and Maxwell took the experiment as verifying the law. However, Maxwell had previously expressed absolute conviction in the law, based on results of Faraday's. So what was the value to Maxwell of replicating Cavendish's experiment? This paper examines the mathematical and instrumental contexts of Maxwell's experiment. It situates the experiment in an assessment of the status of the inverse square law in the 1870s based on textbooks, Maxwell's drive to develop both an electrical programme and a "doctrine of method", and an investigation of the understanding of null methods in the 1870s. It demonstrates that he had previously shifted the evidential context of Faraday's work to suit his aims. It concludes that the experiment served both a...
Drake, James
2010-11-01
Solar and stellar flares, substorms in the Earth's magnetosphere, and disruptions in laboratory fusion experiments are driven by the explosive release of magnetic energy through the process of magnetic reconnection. During reconnection oppositely directed magnetic fields break and cross-connect. The resulting magnetic slingshots convert magnetic energy into high velocity flows, thermal energy and energetic particles. A major scientific challenge has been the multi-scale nature of the problem: a narrow boundary layer, ``the dissipation region,'' breaks field lines and controls the release of energy in a macroscale system. Significant progress has been made on fundamental questions such as how magnetic energy is released so quickly and why the release occurs as an explosion. At the small spatial scales of the dissipation region the motion of electrons and ions decouples, the MHD description breaks down and whistler and kinetic Alfven dynamics drives reconnection. The dispersive property of these waves leads to fast reconnection, insensitive to system size and weakly dependent on dissipation, consistent with observations. The evidence for these waves during reconnection in the magnetosphere and the laboratory is compelling. The role of turbulence within the dissipation region in the form of ``secondary islands'' or as a source of anomalous resistivity continues to be explored. A large fraction of the magnetic energy released during reconnection appears in the form of energetic electrons and protons -- up to 50% or more during solar flares. The mechanism for energetic particle production during magnetic reconnection has remained a mystery. Models based on reconnection at a single large x-line are incapable of producing the large numbers of energetic electrons seen in observations. Scenarios based on particle acceleration in a multi-x-line environment are more promising. In such models a link between the energy gain of electrons and the magnetic energy released, a requirement to explain the observations, has been established. The talk will review key observational data and emphasize basic physical principles to introduce the topic to the non-specialist.[4pt] Thanks to the many colleagues who have contributed to this work. This work was supported by DOE, NASA and NSF.
Organ donation knowledge, willingness, and beliefs of motor vehicle clerks.
Rodrigue, James R; Fleishman, Aaron; Fitzpatrick, Sean; Boger, Matthew
2014-11-27
Motor vehicle (MV) clerks are at the epicenter of organ donor registration. We show that MV clerks (n = 225) in two northeastern states have knowledge gaps and negative beliefs about organ donation. A majority believe it may be possible to buy organs on the black market (81%) and that recovery from brain death is possible (65%), whereas nearly half believe that doctors might not work as hard to save the life of a registered donor (46%). Organ procurement organizations should conduct formal educational programming with MV staff, considering their prominent role in the donor registration process. PMID:25222015
A clerking tool for the patient record system.
McDermott, D; Heathfield, H; Kirby, J
1995-01-01
1. BACKGROUND. The goal of the PEN&PAD (Elderly Care) project is to develop a patient record system to assist the many different professionals that care for patients in a hospital setting. At the core of the project is the use of structured data which can be reused in a variety of ways--both within the system for further manipulation and display, and externally for auditing and statistical purposes. To accommodate these needs, a compositional method of data entry called Structured Data Entry (SDE) was used in this application. SDE was developed in an earlier project PEN&PAD (GP)(1). Our application utilizes a network representation of the medical semantics that can be queried to obtain what is sensible to "say" about a particular concept. This functionality is contained within a separate application known as the Terminology Server (TeS), which has been developed within the GALEN project (2). The client application (the patient record system) requests information from the TeS which can then be used to produce compositional data entry forms that require the user to choose values for given attributes (e.g., if information pertaining to chest pain were being recorded, the attribute 'location' and a choice of possible values i.e., 'left' 'right' and 'bilateral' might appear on the form). Given the importance of capturing clinical information in a highly structured format, SDE is a valuable tool. However, its long term success depends on a very comprehensive model of the medical terminology corpus. This component is currently being studied by the GALEN team. 2. CURRENT WORK. We are developing a clerking tool to be used to create records for the newly admitted patient. The clinician seeks to identify a patient's problems based on physical examination and information obtained through conversation with the patient. Patients are usually admitted with a presenting complaint and obtaining more information about this complaint is an important part of the clerking process. While
Maxwell, Gravitation, and Hodge
Sattinger, D H
2013-01-01
Since Einstein's fundamental paper of 1915, gravitation has been synonymous with General Relativitiy, while theories based on Lorentz invariance have been dismissed as formal analogies. Consequently modern cosmology focusses exclusively on Einstein's geometric theory, which is unnecessarily cumbersome in regions of weak fields, while Maxwell's equations are far more tractable. It is shown here that Maxwell's equations are an {\\it artifact} of Hodge theory, geometric in nature, independent of any specific physical mechanisms, and valid for any force field, attractive or repulsive, generated by a material density and current. In particular, Maxwell's equations apply to weak gravitational fields -- those in Minkowski space-time. Classical analysis and linear partial differential equations therefore have a role to play in modern problems in cosmology. The gravitational field generated by the rotation of a spherical body is computed explicitly using a multipole expansion; and the method is compared with the Lense-...
Obtaining Maxwell's equations heuristically
Diener, Gerhard; Weissbarth, Jürgen; Grossmann, Frank; Schmidt, Rüdiger
2013-02-01
Starting from the experimental fact that a moving charge experiences the Lorentz force and applying the fundamental principles of simplicity (first order derivatives only) and linearity (superposition principle), we show that the structure of the microscopic Maxwell equations for the electromagnetic fields can be deduced heuristically by using the transformation properties of the fields under space inversion and time reversal. Using the experimental facts of charge conservation and that electromagnetic waves propagate with the speed of light, together with Galilean invariance of the Lorentz force, allows us to finalize Maxwell's equations and to introduce arbitrary electrodynamics units naturally.
Maxwell's hypothesis reconsidered
Satheesh, S
2015-01-01
Maxwell's derivaion of the distributions of the velocities of molecules is based on the assumption that the velocity components in the three mutualy orthogonal directions are independent. Here we note that his assumption, the phase space is isotropic, in fact nullifies the effect of a variety of dependencies among the velocity componenets. Thus we can do away with the independence assumption. Further, we observe that his conclusion regarding distribution of the velocity components (Gaussian) remains true under a set of weaker assumptions.
Agnes Mary Clerke and the Rise of Astrophysics
Brück, M. T.
2008-03-01
Acknowledgements; Introduction; 1. Family background in County Cork; 2. Ireland and Italy; 3. London, the literary scene; 4. The History of Astronomy; 5. A circle of astronomers; 6. A visit to South Africa; 7. The System of the Stars; 8. Social life in scientific circles; 9. Homer, the Herschels and a revised History; 10. The opinion moulder; 11. Popularisation, cryogenics and evolution; 12. Problems in Astrophysics; 13. Women in astronomy in Britain in Agnes Clerke's time; 14. Revised System of the Stars; 15. Cosmogonies, cosmology and Nature's spiritual clues; 16. Last days and retrospect; 17. Epilogue; Notes; Appendix; Bibliography; Index.
7 CFR 15f.8 - What does the Docketing Clerk do with my Section 741 Complaint Request?
2010-01-01
... My Complaint Informally With OCR? § 15f.8 What does the Docketing Clerk do with my Section 741 Complaint Request? All Section 741 Complaint Requests docketed by the OCR Docketing Clerk will be...
20 CFR 501.8 - Clerk of the Office of the Appellate Boards; docket of proceedings; records.
2010-04-01
... Boards is located at 200 Constitution Avenue, NW., Washington, DC 20210. The Office of the Clerk is open... 20 Employees' Benefits 3 2010-04-01 2010-04-01 false Clerk of the Office of the Appellate Boards... BOARD, DEPARTMENT OF LABOR RULES OF PROCEDURE § 501.8 Clerk of the Office of the Appellate...
James Clerk Maxwell Prize for Plasma Physics Talk: On Nonlinear Physics of Shear Alfv'en Waves
Chen, Liu
2012-10-01
Shear Alfv'en Waves (SAW) are electromagnetic oscillations prevalent in laboratory and nature magnetized plasmas. Due to its anisotropic propagation property, it is well known that the linear wave propagation and dispersiveness of SAW are fundamentally affected by plasma nonuniformities and magnetic field geometries; for example, the existence of continuous spectrum, spectral gaps, and discrete eigenmodes in toroidal plasmas. This talk will discuss the crucial roles that nonuniformity and geometry could also play in the physics of nonlinear SAW interactions. More specifically, the focus will be on the Alfv'enic state and its breaking up by finite compressibility, non-ideal kinetic effects, and geometry. In the case of compressibility, finite ion-Larmor-radius effects are shown to qualitatively and quantitatively modify the three-wave parametric decays via the ion-sound perturbations. In the case of geometry, the spontaneous excitation of zonal structures by toroidal Alfv'en eigenmodes is investigated; demonstrating that, for realistic tokamak geometries, zonal current dominates over zonal flow. [4pt] Present address: Institute for Fusion Theory and Simulation, Zhejiang University, Hangzhou, China.
Some Variations on Maxwell's Equations
Ascoli, G A; Ascoli, Giorgio A.; Goldin, Gerald A.
2006-01-01
In the first sections of this article, we discuss two variations on Maxwell's equations that have been introduced in earlier work---a class of nonlinear Maxwell theories with well-defined Galilean limits (and correspondingly generalized Yang-Mills equations), and a linear modification motivated by the coupling of the electromagnetic potential with a certain nonlinear Schroedinger equation. In the final section, revisiting an old idea of Lorentz, we write Maxwell's equations for a theory in which the electrostatic force of repulsion between like charges differs fundamentally in magnitude from the electrostatic force of attraction between unlike charges. We elaborate on Lorentz' description by means of electric and magnetic field strengths, whose governing equations separate into two fully relativistic Maxwell systems---one describing ordinary electromagnetism, and the other describing a universally attractive or repulsive long-range force. If such a force cannot be ruled out {\\it a priori\\/} by known physical ...
A pilot randomised controlled trial of medical versus nurse clerking for minor surgery
Rushforth, H.; Bliss, A.; BURGE, D.; Glasper, E. A.
2000-01-01
BACKGROUND—Nurse led clerking is currently practiced in a growing number of UK centres, but there is a paucity of evidence to underpin the safety of this innovation. AIM—To assess the safety of nurse led clerking in paediatric day case and minor surgery. METHODS—Children aged 3 months to 15 years were randomly assigned to clerking by either a nurse or a senior house officer (SHO) (resident). All children were then independently reassessed by a specialist registrar anaestheti...
The Critical Role of Clerks in the Patient-Centered Medical Home.
Solimeo, Samantha L; Stewart, Greg L; Rosenthal, Gary E
2016-07-01
Research evaluating the effectiveness, function, and implementation of patient-centered medical homes (PCMHs) has found major socioprofessional transformations and contributions of primary care physicians and, to a lesser degree, nurses. Our longitudinal ethnographic research with teams implementing PCMH in Veterans Health Administration (VHA) primary care identifies the important but largely underutilized contributions of clerks to PCMH outcomes. Although the relationship of high-performing clerical staff to patient satisfaction is widely acknowledged, PCMH can be further enhanced by enabling clerks to use administrative tasks as conduits for investing in long-term personalized relationships with patients that foster trust in the PCMH and the broader health care organization. Such relationships are engendered through the care-coordination activities clerks perform, which may be bolstered by organizational investment in clerks as skilled health care team members. PMID:27401428
Maxwell stresses and dielectric materials
Kloos, Gerhard
2008-01-01
Electrostatic stresses are a fascinating field where materials science, continuum mechanics and electrical engineering all come together. This is one of the reasons why the study of these so-called Maxwell stresses is so interesting.This treatment of electrostatic Maxwell stresses is restricted to the macroscopic description of the phenomenon, but an attempt is made to provide readers with methods and results which will allow them to deal with cases of low material symmetry, as well as with the effect of viscoelasticity upon the material response. Non-standard orientation of the material samp
Faraday, Maxwell, and the electromagnetic field how two men revolutionized physics
Forbes, Nancy
2014-01-01
The story of two brilliant nineteenth-century scientists who discovered the electromagnetic field, laying the groundwork for the amazing technological and theoretical breakthroughs of the twentieth century Two of the boldest and most creative scientists of all time were Michael Faraday (1791-1867) and James Clerk Maxwell (1831-1879). This is the story of how these two men - separated in age by forty years - discovered the existence of the electromagnetic field and devised a radically new theory which overturned the strictly mechanical view of the world that had prevailed since Newton's time. The authors, veteran science writers with special expertise in physics and engineering, have created a lively narrative that interweaves rich biographical detail from each man's life with clear explanations of their scientific accomplishments. Faraday was an autodidact, who overcame class prejudice and a lack of mathematical training to become renowned for his acute powers of experimental observation, technological skil...
Hydrodynamics for inelastic Maxwell model
Hayakawa, Hisao
2002-01-01
Hydrodynamic equations for an inelastic Maxwell model are derived from the inelastic Boltzmann equation based on a systematic Chapman-Enskog perturbative scheme. Transport coefficients appear in Navier-Stokes order have been determined as a function of the restitution coefficient $e$, which cannot be defined for small $e$ as a result of the high energy tail of the velocity distribution function obeying a power law. The dispersion relations for the linearized equation around a homogeneous cool...
Introduction of New Clinical Clerks to Nursing Procedures and the Ward Laboratory
Kunin, Calvin M.; DeGrott, Jane
1975-01-01
The quality of patient care suffers because of the intellectual separatism that exists among medical, nursing, and other professions. Description of an attempt to introduce knowledge of selected nursing and laboratory skills to third-quarter clinical clerks. (Author/PG)
28 CFR 543.16 - Other paralegals, clerks, and legal assistants.
2010-07-01
... 28 Judicial Administration 2 2010-07-01 2010-07-01 false Other paralegals, clerks, and legal assistants. 543.16 Section 543.16 Judicial Administration BUREAU OF PRISONS, DEPARTMENT OF JUSTICE... may require each assistant to fill out and sign a personal history statement and a pledge to abide...
Responding to New Needs. The Training of Housing Repair Clerks. FEU/PICKUP Project Report.
Brion, Marion; Griggs, Norman
Developers of a seven-day training course for British housing repair clerks offered at Tottenham College of Technology (London, England) reached the following conclusions: (1) such courses should be run "in house" for a particular employer, because job content varies widely; (2) the communications and technical activities in the course should be…
New family of Maxwell like algebras
Concha, P.K.; Durka, R.; Merino, N.; Rodríguez, E. K.
2016-01-01
We introduce an alternative way of closing Maxwell like algebras. We show, through a suitable change of basis, that resulting algebras are given by the direct sums of the AdS and the Maxwell algebras already known in the literature. Casting the result into the S-expansion method framework ensures the straightaway construction of the gravity theories based on a found enlargement.
New family of Maxwell like algebras
Concha, P. K.; Durka, R.; Merino, N.; Rodríguez, E. K.
2016-08-01
We introduce an alternative way of closing Maxwell like algebras. We show, through a suitable change of basis, that resulting algebras are given by the direct sums of the AdS and the Maxwell algebras already known in the literature. Casting the result into the S-expansion method framework ensures the straightaway construction of the gravity theories based on a found enlargement.
Maxwell superalgebras and Abelian semigroup expansion
The Abelian semigroup expansion is a powerful and simple method to derive new Lie algebras from a given one. Recently it was shown that the S-expansion of so(3,2) leads us to the Maxwell algebra M. In this paper we extend this result to superalgebras, by proving that different choices of abelian semigroups S lead to interesting D=4 Maxwell Superalgebras. In particular, the minimal Maxwell superalgebra sM and the N-extended Maxwell superalgebra sM(N) recently found by the Maurer–Cartan expansion procedure, are derived alternatively as an S-expansion of osp(4|N). Moreover, we show that new minimal Maxwell superalgebras type sMm+2 and their N-extended generalization can be obtained using the S-expansion procedure
An axiomatic approach to Maxwell's equations
Heras, José A
2016-01-01
This paper suggests an axiomatic approach to Maxwell's equations. The basis of this approach is a theorem formulated for two sets of functions localized in space and time. If each set satisfies a continuity equation then the theorem provides an integral representation for each function. A corollary of this theorem yields Maxwell's equations with magnetic monopoles. It is pointed out that the causality principle and the conservation of electric and magnetic charges are the most fundamental physical axioms underlying these equations. Another application of the corollary yields Maxwell's equations in material media. The theorem is also formulated in the Minkowski space-time and applied to obtain the covariant form of Maxwell's equations with magnetic monopoles and the covariant form of Maxwell's equations in material media. The approach makes use of the infinite-space Green function of the wave equation and is therefore suitable for an advanced course in electrodynamics.
National Aeronautics and Space Administration, Huntsville, AL. George C. Marshall Space Flight Center.
This pamphlet describes the Space Telescope, an unmanned multi-purpose telescope observatory planned for launch into orbit by the Space Shuttle in the 1980s. The unique capabilities of this telescope are detailed, the major elements of the telescope are described, and its proposed mission operations are outlined. (CS)
The Dust and Gas Content of a Disk Around Young Star HR 4796A
Mannings, V.; Greaves, J.; Holland, W.
1999-01-01
We have used the James Clerk Maxwell Telescope (JCMT) in Hawaii to search at submillimeter wavelengths for continuum emission from dust, and spectral line emission from carbon monoxide (CO) gas, in the neighborhood of HR 4796A.
A quantum-mechanical Maxwell's demon
Lloyd, S
1997-01-01
A Maxwell's demon is a device that gets information and trades it in for thermodynamic advantage, in apparent (but not actual) contradiction to the second law of thermodynamics. Quantum-mechanical versions of Maxwell's demon exhibit features that classical versions do not: in particular, a device that gets information about a quantum system disturbs it in the process. In addition, the information produced by quantum measurement acts as an additional source of thermodynamic inefficiency. This paper investigates the properties of quantum-mechanical Maxwell's demons, and proposes experimentally realizable models of such devices.
N=1 Supergravity and Maxwell superalgebras
Concha, P K
2014-01-01
We present the construction of the $D=4$ supergravity action from the minimal Maxwell superalgebra $s\\mathcal{M}_{4}$, which can be derived from the $\\mathfrak{osp}\\left( 4|1\\right) $ superalgebra by applying the abelian semigroup expansion procedure. We show that $N=1$, $D=4$ pure supergravity can be obtained alternatively as the MacDowell-Mansouri like action built from the curvatures of the Maxwell superalgebra $s\\mathcal{M}_{4}$. We extend this result to all minimal Maxwell superalgebras type $s\\mathcal{M}_{m+2}$. The invariance under supersymmetry transformations is also analized.
Green`s function of Maxwell`s equations and corresponding implications for iterative methods
Singer, B.S. [Macquarie Univ., Sydney (Australia); Fainberg, E.B. [Inst. of Physics of the Earth, Moscow (Russian Federation)
1996-12-31
Energy conservation law imposes constraints on the norm and direction of the Hilbert space vector representing a solution of Maxwell`s equations. In this paper, we derive these constrains and discuss the corresponding implications for the Green`s function of Maxwell`s equations in a dissipative medium. It is shown that Maxwell`s equations can be reduced to an integral equation with a contracting kernel. The equation can be solved using simple iterations. Software based on this algorithm have successfully been applied to a wide range of problems dealing with high contrast models. The matrix corresponding to the integral equation has a well defined spectrum. The equation can be symmetrized and solved using different approaches, for instance one of the conjugate gradient methods.
Cosmic tests of Maxwell's equations. I
Maxwell's equations are usually assumed for cosmic electrodynamics, although they have not been adequately tested and shown to be applicable. Tradition is the main justification for using them. Other electromagnetic theories exist which are of similar antiquity to Maxwell's theory; they have been thoroughly tested for laboratory and terrestrial physics and shown to have consequences indistinguishable from Maxwell's equations for phenomena that occur on these scales. But Maxwell's equations and the alternative theories can provide fundamentally different descriptions of cosmic phenomena. In this paper the possibility that the photon has a non-zero rest mass is examined. In part II of the series it is intended to examine the evidence for the existence of magnetic monopoles. (Auth.)
Maxwell National Wildlife Refuge: Comprehensive Conservation Plan
US Fish and Wildlife Service, Department of the Interior — This Comprehensive Conservation Plan CCP was written to guide management on Maxwell NWR for the next 15 years. This plan outlines the Refuge vision and purpose and...
The stationary Maxwell-Dirac equations
The Maxwell-Dirac equations are the equations for electronic matter, the 'classical' theory underlying QED. The system combines the Dirac equations with the Maxwell equations sourced by the Dirac current. A stationary Maxwell-Dirac system has ψ = e-iEtφ, with φ independent of t. The system is said to be isolated if the dependent variables obey quite weak regularity and decay conditions. In this paper, we prove the following strong localization result for isolated, stationary Maxwell-Dirac systems, - there are no embedded eigenvalues in the essential spectrum, i.e. -m ≤ E ≤ m; - if vertical bar E vertical bar < m then the Dirac field decays exponentially as vertical bar x vertical bar → ∞; - if vertical bar E vertical bar = m then the system is 'asymptotically' static and decays exponentially if the total charge is non-zero
MAXWELL3, 3-D FEM Electromagnetism
1 - Description of program or function: MAXWELL3 is a linear, time domain, finite element code designed for simulation of electromagnetic fields interacting with three-dimensional objects. The simulation region is discretized into 6-sided, 8-nodded elements which need not form a logically regular grid. Scatterers may be perfectly conducting or dielectric. Restart capability and a Muer-type radiating boundary are included. MAXWELL3 can be run in a two-dimensional mode or on infinitesimally thin geometries. The output of time histories on surfaces, or shells, in addition to volumes, is allowed. Two post-processors are included - HIST2XY, which splits the MAXWELL3 history file into simple xy data files, and FFTABS, which performs fast Fourier transformations on the xy data. 2 - Method of solution: The numerical method requires that the model be discretized with a mesh generator. MAXWELL3 then uses the mesh and computes the time domain electric and magnetic fields by integrating Maxwell's divergence-free curl equations over time. The output from MAXWELL3 can then be used with a post-processor to get the desired information in a graphical form. The explicit time integration is done with a leap-frog technique that alternates evaluating the electric and magnetic fields at half time steps. This allows for centered time differencing accurate in second order. The algorithm is naturally robust and requires no parameters. 3 - Restrictions on the complexity of the problem: MAXWELL3 has no mesh generation capabilities. Anisotropic, nonlinear, and magnetic materials cannot be modeled. Material interfaces only account for dielectric changes and neglect any surface charges that would be present at the surface of a partially conducting material. The radiation boundary algorithm is only accurate for normally incident fields and becomes less accurate as the angle of incidence increases. Thus, only models using scattered fields should use the radiation boundary. This limits MAXWELL3's
On fictitious domain formulations for Maxwell's equations
Dahmen, W.; Jensen, Torben Klint; Urban, K.
2003-01-01
We consider fictitious domain-Lagrange multiplier formulations for variational problems in the space H(curl: Omega) derived from Maxwell's equations. Boundary conditions and the divergence constraint are imposed weakly by using Lagrange multipliers. Both the time dependent and time harmonic formu...... formulations of the Maxwell's equations are considered. and we derive well-posed formulations for both cases. The variational problem that arises can be discretized by functions that do not satisfy an a-priori divergence constraint....
Maxwell's equations of electrodynamics an explanation
Ball, David W
2012-01-01
Maxwell's Equations of Electrodynamics: An Explanation is a concise discussion of Maxwell's four equations of electrodynamics - the fundamental theory of electricity, magnetism, and light. It guides readers step-by-step through the vector calculus and development of each equation. Pictures and diagrams illustrate what the equations mean in basic terms. The book not only provides a fundamental description of our universe but also explains how these equations predict the fact that light is better described as "electromagnetic radiation."
Information Thermodynamics: Maxwell's Demon in Nonequilibrium Dynamics
Sagawa, Takahiro; Ueda, Masahito
2011-01-01
We review theory of information thermodynamics which incorporates effects of measurement and feedback into nonequilibrium thermodynamics of a small system, and discuss how the second law of thermodynamics should be extended for such situations. We address the issue of the maximum work that can be extracted from the system in the presence of a feedback controller (Maxwell's demon) and provide a few illustrative examples. We also review a recent experiment that realized a Maxwell's demon based ...
Are Maxwell's equations Lorentz-covariant?
Redzic, D V
2016-01-01
The statement that Maxwell's electrodynamics in vacuum is already covariant under Lorentz transformations is commonplace in the literature. We analyse the actual meaning of that statement and demonstrate that Maxwell's equations are perfectly fit to be Lorentz-covariant; they become Lorentz-covariant if we construct to be so, by postulating certain transformation properties of field functions. In Aristotelian terms, the covariance is a plain potentiality, but not necessarily entelechy.
Carr, J
2002-01-01
This review presents the scientific objectives and status of Neutrino Telescope Projects. The science program of these projects covers: neutrino astronomy, dark matter searches and measurements of neutrino oscillations. The two neutrino telescopes in operation: AMANDA and BAIKAL will be described together with the ANTARES neutrino telescope being built in the Mediterranean. (18 refs).
Magnetic monopoles, Galilean invariance, and Maxwell's equations
Crawford, Frank S.
1992-02-01
Maxwell's equations have space reserved for magnetic monopoles. Whether or not they exist in our part of the universe, monopoles provide a useful didactic tool to help us recognize relations among Maxwell's equations less easily apparent in the approach followed by many introductory textbooks, wherein Coulomb's law, Biot and Savart's law, Ampere's law, Faraday's law, Maxwell's displacement current, etc., are introduced independently, ``as demanded by experiment.'' Instead a conceptual path that deduces all of Maxwell's equations from the near-minimal set of assumptions: (a) Inertial frames exist, in which Newton's laws hold, to a first approximation; (b) the laws of electrodynamics are Galilean invariant-i.e., they have the same form in every inertial frame, to a first approximation; (c) magnetic poles (as well as the usual electric charges) exist; (d) the complete Lorentz force on an electric charge is known; (e) the force on a monopole at rest is known; (f) the Coulomb-like field produced by a resting electric charge and by a resting monopole are known. Everything else is deduced. History is followed in the assumption that Newtonian mechanics have been discovered, but not special relativity. (Only particle velocities v<
Magnetic monopoles, Galilean invariance, and Maxwell's equations
Maxwell's equations have space reserved for magnetic monopoles. Whether or not they exist in our part of the universe, monopoles provide a useful didactic tool to help us recognize relations among Maxwell's equations less easily apparent in the approach followed by many introductory textbooks, wherein Coulomb's law, Biot and Savart's law, Ampere's law, Faraday's law, Maxwell's displacement current, etc., are introduced independently, ''as demanded by experiment.'' Instead a conceptual path that deduces all of Maxwell's equations from the near-minimal set of assumptions: (a) Inertial frames exist, in which Newton's laws hold, to a first approximation; (b) the laws of electrodynamics are Galilean invariant---i.e., they have the same form in every inertial frame, to a first approximation; (c) magnetic poles (as well as the usual electric charges) exist; (d) the complete Lorentz force on an electric charge is known; (e) the force on a monopole at rest is known; (f) the Coulomb-like field produced by a resting electric charge and by a resting monopole are known. Everything else is deduced. History is followed in the assumption that Newtonian mechanics have been discovered, but not special relativity. (Only particle velocities v much-lt c are considered.) This ends up with Maxwell's equations (Maxwell did not need special relativity, so why should we,) but facing Einstein's paradox, the solution of which is encapsulated in the Einstein velocity-addition formula
Modified Maxwell equations in quantum electrodynamics
Harmuth, Henning F; Meffert, Beate
2001-01-01
Divergencies in quantum field theory referred to as "infinite zero-point energy" have been a problem for 70 years. Renormalization has always been considered an unsatisfactory remedy. In 1985 it was found that Maxwell's equations generally do not have solutions that satisfy the causality law. An additional term for magnetic dipole currents corrected this shortcoming. Rotating magnetic dipoles produce magnetic dipole currents, just as rotating electric dipoles in a material like barium titanate produce electric dipole currents. Electric dipole currents were always part of Maxwell's equations. T
Generalized Maxwell equations and charge conservation censorship
Modanese, G
2016-01-01
The Aharonov-Bohm electrodynamics is a generalization of Maxwell theory with reduced gauge invariance. It allows to couple the electromagnetic field to a charge which is not locally conserved, and has an additional degree of freedom, the scalar field $S=\\partial_\\alpha A^\\alpha$, usually interpreted as a longitudinal wave component. By re-formulating the theory in a compact Lagrangian formalism, we are able to eliminate $S$ explicitly from the dynamics and we obtain generalized Maxwell equation with interesting properties: they give $\\partial_\\mu F^{\\mu \
Maxwell-Chern-Simons Theory With Boundary
Blasi, A; Magnoli, N; Storace, S
2010-01-01
The Maxwell-Chern-Simons (MCS) theory with planar boundary is considered. The boundary is introduced according to Symanzik's basic principles of locality and separability. A method of investigation is proposed, which, avoiding the straight computation of correlators, is appealing for situations where the computation of propagators, modified by the boundary, becomes quite complex. For MCS theory, the outcome is that a unique solution exists, in the form of chiral conserved currents, satisfying a Kac-Mody algebra, whose central charge does not depend on the Maxwell term.
Ramos, Mauro Cunha; da Silva, Rodrigo D Correa; Gobbato, Ricardo O; da Rocha, Felipe Civeira; de Lucca Júnior, Giusepe; Vissoky, Jacques; Cestari, Tania; Filgueiras, Absalom
2004-05-01
STDs are a significant public health problem in Brazil. A primary control strategy is the immediate treatment of symptomatic individuals. When services are unavailable, STD patients seek care in alternative settings. Probably the most frequently used settings are commercial pharmacies, where pharmacy clerks provide treatment, although Brazilian law prohibits selling antibiotics without prescription. Our objective was to evaluate prescribing practices by pharmacy clerks for STDs. We performed a cross-sectional study. Trained medical students visited 62 pharmacies in the city of Porto Alegre during March 2002. These were randomly chosen from a list of 863 registered pharmacies. The students presented to the pharmacy complaining of dysuria and urethral discharge. After obtaining a prescription, or not, they asked for additional instructions to be followed. Immediately after leaving the premises, the instructions were anonymously recorded. Of the 62 pharmacies visited, a clerk in 56 (90.3%, 95% confidence interval [CI]: 80.1%-96.4%) provided a prescription. Most frequently prescribed drugs were ampicillin with probenecide (29/51.8%) and rosoxacin (11/19.6%). Ministry of Health-recommended treatment was not suggested by any of the clerks. Forty-six additional recommendations were given. The use of condoms was the most frequent additional advice (42/46). Prescribing by pharmacy clerks is very prevalent in Porto Alegre. This may represent a lost opportunity for more comprehensive prevention effort (counselling, partner management, and diagnosing other STDs). Additionally, the most frequently prescribed drugs are not recommended by international or national health authorities for treatment of STDs, and none of these drugs covers chlamydia. We conclude that pharmacy clerks are a potentially important source of STD treatment and control but that their practices are in need of vast improvement. PMID:15117504
Hanson, Mark D.; Szatmari, Peter; Eva, Kevin W.
2011-01-01
Objective: The authors evaluated the differential impact of clerk interest and participation in a Child and Adolescent Psychiatry (CAP) clerkship rotation upon psychiatry and pediatrics residency matches. Method: Authors studied clerks from the McMaster University M.D. program graduating years of 2005-2007. Participants were categorized as 1)…
Maxwell Equations for Slow-Moving Media
Rozov, Andrey
2015-12-01
In the present work, the Minkowski equations obtained on the basis of theory of relativity are used to describe electromagnetic fields in moving media. But important electromagnetic processes run under non-relativistic conditions of slow-moving media. Therefore, one should carry out its description in terms of classical mechanics. Hertz derived electrodynamic equations for moving media within the frame of classical mechanics on the basis of the Maxwell theory. His equations disagree with the experimental data concerned with the moving dielectrics. In the paper, a way of description of electromagnetic fields in slow-moving media on the basis of the Maxwell theory within the frame of classical mechanics is offered by combining the Hertz approach and the experimental data concerned with the movement of dielectrics in electromagnetic fields. Received Maxwell equations lack asymmetry in the description of the reciprocal electrodynamic action of a magnet and a conductor and conform to known experimental data. Comparative analysis of the Minkowski and Maxwell models is carried out.
Maxwell's electromagnetic theory and special relativity.
Hall, Graham
2008-05-28
This paper presents a brief history of electromagnetic theory from ancient times up to the work of Maxwell and the advent of Einstein's special theory of relativity. It is divided into five convenient periods and the intention is to describe these developments for the benefit of a lay scientific audience and with the minimum of technical detail. PMID:18218598
Quantum form of Nonlinear Maxwell Equation
Chen, Y.; F. L. Zhang; Chen, J L
2010-01-01
We generalize Maxwell equations which describe the vacuum of quantum electrodynamics into the quantum form. This nontraditional approach is different from the widely used theory|-Quantum Electrodynamics. From another viewpoint, it could be a direction for interpreting quantum theories properly.
What physics is encoded in Maxwell's equations?
Kosyakov, B. P.
2005-08-01
We reconstruct Maxwell's equations showing that a major part of the information encoded in them is taken from topological properties of spacetime, and the residual information, divorced from geometry, which represents the physical contents of electrodynamics, %these equations, translates into four assumptions:(i) locality; (ii) linearity; %of the dynamical law; (iii) identity of the charge-source and the charge-coupling; and (iv) lack of magnetic monopoles. However, a closer inspection of symmetries peculiar to electrodynamics shows that these assumptions may have much to do with geometry. Maxwell's equations tell us that we live in a three-dimensional space with trivial (Euclidean) topology; time is a one-dimensional unidirectional and noncompact continuum; and spacetime is endowed with a light cone structure readable in the conformal invariance of electrodynamics. Our geometric feelings relate to the fact that Maxwell's equations are built in our brain, hence our space and time orientation, our visualization and imagination capabilities are ensured by perpetual instinctive processes of solving Maxwell's equations. People are usually agree in their observations of angle relations, for example, a right angle is never confused with an angle slightly different from right. By contrast, we may disagree in metric issues, say, a colour-blind person finds the light wave lengths quite different from those found by a man with normal vision. This lends support to the view that conformal invariance of Maxwell's equations is responsible for producing our notion of space. Assuming that our geometric intuition is guided by our innate realization of electrodynamical laws, some abnormal mental phenomena, such as clairvoyance, may have a rational explanation.
Rigby, Jane R.
2011-01-01
The science of astronomy depends on modern-day temples called telescopes. Astronomers make pilgrimages to remote mountaintops where these large, intricate, precise machines gather light that rains down from the Universe. Bit, since Earth is a bright, turbulent planet, our finest telescopes are those that have been launched into the dark stillness of space. These space telescopes, named after heroes of astronomy (Hubble, Chandra, Spitzer, Herschel), are some of the best ideas our species has ever had. They show us, over 13 billion years of cosmic history, how galaxies and quasars evolve. They study planets orbiting other stars. They've helped us determine that 95% of the Universe is of unknown composition. In short, they tell us about our place in the Universe. The next step in this journey is the James Webb Space Telescope, being built by NASA, Europe, and Canada for a 2018 launch; Webb will reveal the first galaxies that ever formed.
Lampton, Michael L.; Akerlof, C.W.; Aldering, G.; Amanullah, R.; Astier, P.; Barrelet, E.; Bebek, C.; Bergstrom, L.; Bercovitz, J.; Bernstein, G.; Bester, M.; Bonissent, A.; Bower, C.; Carithers Jr., W.C.; Commins, E.D.; Day, C.; Deustua, S.E.; DiGennaro, R.; Ealet, A.; Ellis,R.S.; Eriksson, M.; Fruchter, A.; Genat, J.-F.; Goldhaber, G.; Goobar,A.; Groom, D.; Harris, S.E.; Harvey, P.R.; Heetderks, H.D.; Holland,S.E.; Huterer, D.; Karcher, A.; Kim, A.G.; Kolbe, W.; Krieger, B.; Lafever, R.; Lamoureux, J.; Levi, M.E.; Levin, D.S.; Linder, E.V.; Loken,S.C.; Malina, R.; Massey, R.; McKay, T.; McKee, S.P.; Miquel, R.; Mortsell, E.; Mostek, N.; Mufson, S.; Musser, J.; Nugent, P.; Oluseyi,H.; Pain, R.; Palaio, N.; Pankow, D.; Perlmutter, S.; Pratt, R.; Prieto,E.; Refregier, A.; Rhodes, J.; Robinson, K.; Roe, N.; Sholl, M.; Schubnell, M.; Smadja, G.; Smoot, G.; Spadafora, A.; Tarle, G.; Tomasch,A.; von der Lippe, H.; Vincent, R.; Walder, J.-P.; Wang, G.; Wang, G.
2002-07-29
The SuperNova/Acceleration Probe (SNAP) mission will require a two-meter class telescope delivering diffraction limited images spanning a one degree field in the visible and near infrared wavelength regime. This requirement, equivalent to nearly one billion pixel resolution, places stringent demands on its optical system in terms of field flatness, image quality, and freedom from chromatic aberration. We discuss the advantages of annular-field three-mirror anastigmat (TMA) telescopes for applications such as SNAP, and describe the features of the specific optical configuration that we have baselined for the SNAP mission. We discuss the mechanical design and choice of materials for the telescope. Then we present detailed ray traces and diffraction calculations for our baseline optical design. We briefly discuss stray light and tolerance issues, and present a preliminary wavefront error budget for the SNAP Telescope. We conclude by describing some of tasks to be carried out during the upcoming SNAP research and development phase.
Kellerer, Aglae
2014-01-01
In the 20th century, quantum mechanics connected the particle and wave concepts of light and thereby made mechanisms accessible that had never been imagined before. Processes such as stimulated emission and quantum entanglement have revolutionized modern technology. But even though astronomical observations rely on novel technologies, the optical layout of telescopes has fundamentally remained unchanged. While there is no doubt that Huyghens and Newton would be astounded by the size of our modern telescopes, they would nevertheless understand their optical design. The time may now have come to consider quantum telescopes, that make use of the fundamental scientific changes brought along by quantum mechanics. While one aim is to entertain our reader, our main purpose is to explore the possible future evolution of telescopes.
Picard, Rainer; Trostorff, Sascha; Waurick, Marcus
2014-01-01
Maxwell's equation, Dirac's equation and the equation of gravito-electromagnetism are shown to be particular instances of the extended Maxwell system. The equations are discussed in the framework of the theory of evolutionary equations. Their formal relationship are systematically analyzed. Applications to coupled systems such as the Maxwell-Dirac system are also discussed.
Maxwell Duality, Lorentz Invariance, and Topological Phase
Dowling, J P; Franson, J D; Dowling, Jonathan P.; Williams, Colin P.
1999-01-01
We discuss the Maxwell electromagnetic duality relations between the Aharonov-Bohm, Aharonov-Casher, and He-McKellar-Wilkens topological phases, which allows a unified description of all three phenomena. We also elucidate Lorentz transformations that allow these effects to be understood in an intuitive fashion in the rest frame of the moving quantum particle. Finally, we propose a realistic set up for measuring and interpreting the He-McKellar-Wilkens phase directly in an experiment.
Charging Capacitors According to Maxwell's Equations: Impossible
Funaro, Daniele
2014-01-01
The charge of an ideal parallel capacitor leads to the resolution of the wave equation for the electric field with prescribed initial conditions and boundary constraints. Independently of the capacitor's shape and the applied voltage, none of the corresponding solutions is compatible with the full set of Maxwell's equations. The paradoxical situation persists even by weakening boundary conditions, resulting in the impossibility to describe a trivial phenomenon such as the capacitor's charging process, by means of the standard Maxwellian theory.
Charging Capacitors According to Maxwell's Equations: Impossible
Funaro, Daniele
2014-01-01
The charge of an ideal parallel capacitor leads to the resolution of the wave equation for the electric field with prescribed initial conditions and boundary constraints. Independently of the capacitor's shape and the applied voltage, none of the corresponding solutions is compatible with the full set of Maxwell's equations. The paradoxical situation persists even by weakening boundary conditions, resulting in the impossibility to describe a trivial phenomenon such as the capacitor's charging...
Maxwell Optics: II. An Exact Formalism
Khan, Sameen Ahmed
2002-01-01
We present a formalism for light optics starting with the Maxwell equations and casting them into an exact matrix form taking into account the spatial and temporal variations of the permittivity and permeability. This $8 \\times 8$ matrix representation is used to construct the optical Hamiltonian. This has a close analogy with the algebraic structure of the Dirac equation, enabling the use of the rich machinery of the Dirac electron theory. We get interesting wavelength-dependent contribution...
Quantum Maxwell's Demon in Thermodynamic Cycles
Dong, H.; Xu, D. Z.; Sun, C. P.
2010-01-01
We study the physical mechanism of Maxwell's Demon (MD) helping to do extra work in thermodynamic cycles, by describing measurement of position, insertion of wall and information erasing of MD in a quantum mechanical fashion. The heat engine is exemplified with one molecule confined in an infinitely deep square potential inserted with a movable solid wall, while the MD is modeled as a two-level system (TLS) for measuring and controlling the motion of the molecule. It is discovered that the th...
An Asymmetry in the Maxwell Equations
Towe, Joseph
2006-01-01
A term in the Maxwell-Ampere law describes a linear displacement current that is symmetrically enclosed by the curl of a magnetic field. In this context symmetry calls for a term in the Faraday-Lenz law, which in the absence of a conducting coil would describe a loop of displacement current about a linear increment of magnetic flux. This term, introduced to satisfy symmetry, predicts a physical phenomenon that has recently been observed.
Infinitesimal Carnot cycle and Maxwell's first relation
We demonstrate that by employing usual calculus along with the first law, the efficiency of a Carnot cycle can be evaluated when the working substance has an arbitrary equation of state. This leads to a neat derivation of Maxwell's first relation without using either the properties of perfect differentials as done by Tjiang and Sutanto or the abstract symbolism of topology as done by Hannay
Loading Relativistic Maxwell Distributions in Particle Simulations
Zenitani, Seiji
2015-01-01
Numerical algorithms to load relativistic Maxwell distributions in particle-in-cell (PIC) and Monte-Carlo simulations are presented. For stationary relativistic Maxwellian, the inverse transform method and the Sobol algorithm are reviewed. To boost particles to obtain relativistic shifted-Maxwellian, two rejection methods are proposed in a physically transparent manner. Their acceptance efficiencies are ${\\approx}50\\%$ for generic cases and $100\\%$ for symmetric distributions. They can be combined with arbitrary base algorithms.
As usual methods to cool gases down to a temperature close to the absolute zero are only efficient for some species, a combination of two techniques is used to cool almost all atoms, and even some molecules. An inverted magnetic rail gun first slows down atoms. Cooling is then carried on by means of a technique inspired by the 'Maxwell demon' imagined in 1780. Applications under investigation are ranging from the study of elementary particle properties to isotope separation
Transport coefficients for inelastic Maxwell mixtures
Garzo, Vicente; Astillero, Antonio
2004-01-01
The Boltzmann equation for inelastic Maxwell models is used to determine the Navier-Stokes transport coefficients of a granular binary mixture in $d$ dimensions. The Chapman-Enskog method is applied to solve the Boltzmann equation for states near the (local) homogeneous cooling state. The mass, heat, and momentum fluxes are obtained to first order in the spatial gradients of the hydrodynamic fields, and the corresponding transport coefficients are identified. There are seven relevant transpor...
Hydrodynamics for inelastic Maxwell mixtures: Some applications
Garzo, Vicente; Montanero, Jose Maria
2004-01-01
Hydrodynamic equations for a binary mixture of inelastic Maxwell models described by the Boltzmann equation are derived. The Navier-Stokes transport coefficients are {\\em exactly} obtained by solving the Boltzmann equation from the Chapman-Enskog method for states close to the (local) homogeneous cooling state (HCS). The knowledge of the transport coefficients allows one to analyze two different problems. First, we solve the linearized hydrodynamic equations around the homogeneous (cooling) s...
An Asymmetry in the Maxwell Equations
Towe, J
2006-01-01
A term in the Maxwell-Ampere law describes a linear displacement current that is symmetrically enclosed by a magnetic flux. Symmetry therefore calls for a term in the Faraday-Lenz law, which in the absence of a conducting coil would describe a loop of displacement current about a linear increment of magnetic flux. This term, introduced to satisfy symmetry, predicts a physical phenomenon that has recently been observed.
Noncommutative Einstein-Maxwell pp-waves
Ruiz Ruiz, Fernando; Marculescu, S.
2006-01-01
The field equations coupling a Seiberg-Witten electromagnetic field to noncommutative gravity, as described by a formal power series in the noncommutativity parameters $\\theta^{\\alpha\\beta}$, is investigated. A large family of solutions, up to order one in $\\theta^{\\alpha\\beta}$, describing Einstein-Maxwell null pp-waves is obtained. The order-one contributions can be viewed as providing noncommutative corrections to pp-waves. In our solutions, noncommutativity enters the spacetime metric thr...
Héctor Torres-Silva
2008-11-01
Full Text Available This work deals with the problem of the construction of the Lagrange functional for an electromagnetic field. The generalised Maxwell equations for an electromagnetic field in free space are introduced. The main idea relies on the change of Lagrange function under the integral action. Usually, the Lagrange functional which describes the electromagnetic field is built with the quadrate of the electromagnetic field tensor . Such a quadrate term is the reason, from a mathematical point of view, for the linear form of the Maxwell equations in free space. The author does not make this assumption and nonlinear Maxwell equations are obtained. New material parameters of free space are established. The equations obtained are quite similar to the well-known Maxwell equations. The energy tensor of the electromagnetic field from a chiral approach to the Born Infeld Lagrangian is discussed in connection with the cosmological constant.Se aborda el problema de la construcción de la funcional de Lagrange de un campo electromagnético. Se introducen las ecuaciones generalizadas de Maxwell de un campo electromagnético en el espacio libre. La idea principal se basa en el cambio de función de Lagrange en virtud de la acción integral. Por lo general, la funcional de lagrange, que describe el campo electromagnético, se construye con el cuadrado del tensor de campo electromagnético. Ese término cuadrático es la razón, desde un punto de vista matemático, de la forma lineal de las ecuaciones de Maxwell en el espacio libre. Se obtienen las ecuaciones no lineales de Maxwell sin considerar esta suposición. Las ecuaciones de Maxwell obtenidas son bastante similares a las conocidas ecuaciones de Maxwell. Se analiza el tensor de energía del campo electromagnético en un enfoque quiral de la Lagrangiana de Born Infeld en relación con la constante cosmológica.
The numerical solution of Maxwell equations is a challenging task. Moreover, the range of applications is very wide: microwave devices, diffraction, to cite a few. As a result, a number of methods have been proposed since the sixties. However, among all these methods, none has proved to be free of drawbacks. The finite difference scheme proposed by Yee in 1966, is well suited for Maxwell equations. However, it only works on cubical mesh. As a result, the boundaries of complex objects are not properly handled by the scheme. When classical nodal finite elements are used, spurious modes appear, which spoil the results of simulations. Edge elements overcome this problem, at the price of rather complex implementation, and computationally intensive simulations. Finite volume methods, either generalizing Yee scheme to a wider class of meshes, or applying to Maxwell equations methods initially used in the field of hyperbolic systems of conservation laws, are also used. Lastly, 'Discontinuous Galerkin' methods, generalizing to arbitrary order of accuracy finite volume methods, have recently been applied to Maxwell equations. In this report, we more specifically focus on the coupling of a Maxwell solver to a PIC (Particle-in-cell) method. We analyze advantages and drawbacks of the most widely used methods: accuracy, robustness, sensitivity to numerical artefacts, efficiency, user judgment. (authors)
FDTD for Hydrodynamic Electron Fluid Maxwell Equations
Yingxue Zhao
2015-05-01
Full Text Available In this work, we develop a numerical method for solving the three dimensional hydrodynamic electron fluid Maxwell equations that describe the electron gas dynamics driven by an external electromagnetic wave excitation. Our numerical approach is based on the Finite-Difference Time-Domain (FDTD method for solving the Maxwell’s equations and an explicit central finite difference method for solving the hydrodynamic electron fluid equations containing both electron density and current equations. Numerical results show good agreement with the experiment of studying the second-harmonic generation (SHG from metallic split-ring resonator (SRR.
From Hamiltonian chaos to Maxwell's Demon
The problem of the existence of Maxwell's Demon (MD) is formulated for systems with dynamical chaos. Property of stickiness of individual trajectories, anomalous distribution of the Poincare recurrence time, and anomalous (non-Gaussian) transport for a typical system with Hamiltonian chaos results in a possibility to design a situation equivalent to the MD operation. A numerical example demonstrates a possibility to set without expenditure of work a thermodynamically non-equilibrium state between two contacted domains of the phase space lasting for an arbitrarily long time. This result offers a new view of the Hamiltonian chaos and its role in the foundation of statistical mechanics. copyright 1995 American Institute of Physics
Maxwell's equations and their consequences elementary electromagnetic theory
Chirgwin, B H; Kilmister, C W 0
2013-01-01
Elementary Electromagnetic Theory Volume 3: Maxwell's Equations and their Consequences is the third of three volumes that intend to cover electromagnetism and its potential theory. The third volume considers the implications of Maxwell's equations, such as electromagnetic radiation in simple cases, and its relation between Maxwell's equation and the Lorenz transformation. Included in this volume are chapters 11-14, which contain an in-depth discussion of the following topics: Electromagnetic Waves The Lorentz Invariance of Maxwell's Equation Radiation Motion of Charged Particles Intended
Roman Leischik; Peter Foshag; Markus Strauß; Henning Littwitz; Pankaj Garg; Birgit Dworrak; Marc Horlitz
2015-01-01
Background This study examined the association between the physical work environment and physiological performance measures, physical activity levels and metabolic parameters among German civil servants. A main focus in this study was to examine the group differences rather than measuring the absolute values in an occupational group. Methods We prospectively examined 198 male German civil servants (97 firefighters [FFs], 55 police officers [POs] and 46 sedentary clerks [SCs]). For each parame...
Chow, Jij; Yvon, Camille; Stanger, Tim
2014-01-01
Clerking a patient is the first and most important contact that any medical team has with the patient. It provides information that may not be available later in the admission if recorded improperly, such as referral letters, collateral history, dosette boxes or prescription sheets. The quality of data recorded from this encounter was examined at a busy district general hospital surgical department. Initial measurement demonstrated that less than half of certain key parameters like dosages of...
Comparing Teaching Approaches About Maxwell's Displacement Current
Karam, Ricardo; Coimbra, Debora; Pietrocola, Maurício
2014-08-01
Due to its fundamental role for the consolidation of Maxwell's equations, the displacement current is one of the most important topics of any introductory course on electromagnetism. Moreover, this episode is widely used by historians and philosophers of science as a case study to investigate several issues (e.g. the theory-experiment relationship). Despite the consensus among physics educators concerning the relevance of the topic, there are many possible ways to interpret and justify the need for the displacement current term. With the goal of understanding the didactical transposition of this topic more deeply, we investigate three of its domains: (1) The historical development of Maxwell's reasoning; (2) Different approaches to justify the term insertion in physics textbooks; and (3) Four lectures devoted to introduce the topic in undergraduate level given by four different professors. By reflecting on the differences between these three domains, significant evidence for the knowledge transformation caused by the didactization of this episode is provided. The main purpose of this comparative analysis is to assist physics educators in developing an epistemological surveillance regarding the teaching and learning of the displacement current.
Aspects associated with sick leaves of bank clerks owing to RSI/WMSD
Camilla Zavarizzi
2014-12-01
Full Text Available Objective: To investigate the aspects related to sick leaves of bank clerks, owing to repetitive strain injuries (RSI, attended at the Reference Center of Occupational Health - CEREST in the municipality of Santos, Sao Paulo state, Brazil, and their association with work organisation and conditions. Material and methods: Analyses of spreadsheets of subjects attended in the Reference Center of Occupational Health between January and December 2010, with clinical diagnoses related to soft tissue injuries from ICD-10. Two hundred six spreadsheets were analyzed, and 17.9% (n=37 of the subjects presented soft tissue injuries; eight of them were from the banking sector. Subsequently, the banking sector subjects that were or had been on sick leave were selected. A script was developed with semi-structured questions about the work environment, sickness process, and sick leave, among others. The interviews were recorded for integral verbatim transcription and categorical analyses. Results: Five subjects aged 40 to 62 participated in the study: four females and one male. Regarding schooling, all of them presented higher education level, three complete and two incomplete. Their statements revealed aspects such as intense rhythm and repetitiveness, humiliation in meetings, requirement for meeting targets, musculoskeletal symptoms at work, and fear of losing the job, among others. Final considerations: Some aspect of work organisation and conditions generated distress and suffering, and were associated with the sickening and sick leave processes.
Coset Algebras of the Maxwell-Einstein Supergravities
Yilmaz, Nejat Tevfik
2006-01-01
The general structure of the scalar cosets of the Maxwell-Einstein supergravities is given. Following an introduction of the non-linear coset formalism of the supergravity theories a comparison of the coset algebras of the Maxwell-Einstein supergravities in various dimensions is discussed.
Electromagnetic modes of Maxwell fish-eye lens
Rosu, H C
1996-01-01
We provide an analysis of the radial structure of TE and TM modes of the Maxwell fisheye lens, by means of Maxwell equations as applied to the fisheye case. Choosing a lens of size R = 1 cm, we plot some of the modes in the infrared range.
Maxwell Equations and the Redundant Gauge Degree of Freedom
Wong, Chun Wa
2009-01-01
On transformation to the Fourier space (k,[omega]), the partial differential Maxwell equations simplify to algebraic equations, and the Helmholtz theorem of vector calculus reduces to vector algebraic projections. Maxwell equations and their solutions can then be separated readily into longitudinal and transverse components relative to the…
Post-Newtonian approximation in Maxwell-like form
The equations of the linearized first post-Newtonian approximation to general relativity are often written in 'gravitoelectromagnetic' Maxwell-like form, since that facilitates physical intuition. Damour, Soffel, and Xu (DSX) (as a side issue in their complex but elegant papers on relativistic celestial mechanics) have expressed the first post-Newtonian approximation, including all nonlinearities, in Maxwell-like form. This paper summarizes that DSX Maxwell-like formalism (which is not easily extracted from their celestial mechanics papers), and then extends it to include the post-Newtonian (Landau-Lifshitz-based) gravitational momentum density, momentum flux (i.e. gravitational stress tensor), and law of momentum conservation in Maxwell-like form. The authors and their colleagues have found these Maxwell-like momentum tools useful for developing physical intuition into numerical-relativity simulations of compact binaries with spin.
Mechanical Weyl Modes in Topological Maxwell Lattices
Rocklin, D. Zeb; Chen, Bryan Gin-ge; Falk, Martin; Vitelli, Vincenzo; Lubensky, T. C.
2016-04-01
We show that two-dimensional mechanical lattices can generically display topologically protected bulk zero-energy phonon modes at isolated points in the Brillouin zone, analogs of massless fermion modes of Weyl semimetals. We focus on deformed square lattices as the simplest Maxwell lattices, characterized by equal numbers of constraints and degrees of freedom, with this property. The Weyl points appear at the origin of the Brillouin zone along directions with vanishing sound speed and move away to the zone edge (or return to the origin) where they annihilate. Our results suggest a design strategy for topological metamaterials with bulk low-frequency acoustic modes and elastic instabilities at a particular, tunable finite wave vector.
Maxwell's refrigerator: an exactly solvable model.
Mandal, Dibyendu; Quan, H T; Jarzynski, Christopher
2013-07-19
We describe a simple and solvable model of a device that-like the "neat-fingered being" in Maxwell's famous thought experiment-transfers energy from a cold system to a hot system by rectifying thermal fluctuations. In order to accomplish this task, our device requires a memory register to which it can write information: the increase in the Shannon entropy of the memory compensates the decrease in the thermodynamic entropy arising from the flow of heat against a thermal gradient. We construct the nonequilibrium phase diagram for this device, and find that it can alternatively act as an eraser of information. We discuss our model in the context of the second law of thermodynamics. PMID:23909304
Anomalous Maxwell equations for inhomogeneous chiral plasma
Gorbar, E V; Vilchinskii, S; Rudenok, I; Boyarsky, A; Ruchayskiy, O
2016-01-01
Using the chiral kinetic theory we derive the electric and chiral current densities in inhomogeneous relativistic plasma. We also derive equations for the electric and chiral charge chemical potentials that close the Maxwell equations in such a plasma. The analysis is done in the regimes with and without a drift of the plasma as a whole. In addition to the currents present in the homogeneous plasma (Hall current, chiral magnetic, chiral separation, and chiral electric separation effects, as well as Ohm's current) we derive several new terms associated with inhomogeneities of the plasma. Apart from various diffusion-like terms, we find also new dissipation-less terms that are independent of relaxation time. Their origin can be traced to the Berry curvature modifications of the kinetic theory.
An Eulerian gyrokinetic-Maxwell solver
Candy, J
2003-01-01
In this report we present a time-explicit, Eulerian numerical scheme for the solution of the nonlinear gyrokinetic-Maxwell equations. The treatment of electrons is fully drift-kinetic, transverse electromagnetic fluctuations are included, and profile variation is allowed over an arbitrary radial annulus. The code, gyro, is benchmarked against analytic theory, linear eigenmode codes, and nonlinear electrostatic gyrokinetic particle-in-cell codes. We have attempted preliminary finite-beta calculations in the range beta/beta sub c sub r sub i sub t =[0.0,0.5] for a reference discharge. Detailed diagnostic data is presented for these simulations, along with a number of caveats which reflect the uncharted nature of the parameter regime.
An extended formulation of Maxwell's equations
An extended Lorentz invariant formulation of Maxwell's equations is presented which both includes time dependent and steady-state solutions. In this approach the charge and current densities are treated as intrinsic properties of the electromagnetic field itself, in vacuo. Two main results follow from such an approach. First, a longitudinal electric wave is predicted to propagate in vacuo. Second, an axially symmetric steady state can be outlined in which 'self-confined' electromagnetic radiation circulates in closed orbits around the axis of symmetry. For this state values are obtained of the charge, the spin, and the product between magnetic moment and mass which are of the same order of magnitude as those observed for some elementary particles such as the proton and electron. Consequently, this may provide certain areas of conventional elementary particle analysis with some complementary ideas. Whether the predicted new phenomena also correspond to physical realities is so far an open question which requires further investigation. With 6 refs. (Author)
Relativistic Entanglement From Maxwell's Classical Equations
Carroll, John E.; Quarterman, Adrian H.
2013-09-01
With the help of light cone coordinates and light cone field representations of Maxwell's classical equations, quantum polarization entanglement is explained using the relativistic results of a companion paper that shows how conventional or reference waves can have an adjoint wave, travelling in phase with the reference wave, but in a proper relativistic frame that travels in the opposing direction to the proper frame of the reference wave. This subsequently allows waves, travelling in opposite directions, to have the same proper frame and consequently such waves can be regarded as relativistically local. The light cone coordinates offer a classical form of a quantum wave function and demonstrate a classical equivalent of a mixed quantum state.
Nonminimal Einstein-Maxwell-Vlasov-axion model
Balakin, Alexander B; Zayats, Alexei E
2014-01-01
We establish a new self-consistent system of equations accounting for a nonminimal coupling of the cooperative gravitational, electromagnetic and pseudoscalar (axion) fields in a multi-component relativistic plasma. The axionic extension of the nonminimal Einstein-Maxwell-Vlasov theory is based on two consistent procedures. First, we use the Lagrange formalism to obtain nonminimal equations for the gravitational, electromagnetic and pseudoscalar fields with the additional sources generated in plasma. Second, we use the Vlasov version of the relativistic kinetic theory of the plasma, guided by the cooperative macroscopic electromagnetic, gravitational and axionic fields, to describe adequately the response of the plasma on the variations of these fields. In order to show the self-consistency of this approach we check directly the compatibility conditions for the master equations for the cooperative fields. Using these compatibility conditions we reconstruct the ponderomotive force, which acts on the plasma par...
On the Vlasov-Maxwell Equations
Zadorozhny, Vladimir F
2005-01-01
There are many interesting physical question which based on of the solution Vlasov-Maxwell Equation (VME). However, the procedure of solve is very difficult and hard. But it is often preferable, on physical grounds, to a common point of view. Such point of view maybe a structure of some solution. We define and discuss the notaion of structure for the distribution function and prove, the structure of the Lorentz force represent the structure of the one. At the time of the discovery of the integrable systems the question of VME integrability had been considered. Moreover, as example, we consider, by means of this approach, the relation integrability and dispersion with a spectra of Vlasov's operat.
Fractional vector calculus and fractional Maxwell's equations
The theory of derivatives and integrals of non-integer order goes back to Leibniz, Liouville, Grunwald, Letnikov and Riemann. The history of fractional vector calculus (FVC) has only 10 years. The main approaches to formulate a FVC, which are used in the physics during the past few years, will be briefly described in this paper. We solve some problems of consistent formulations of FVC by using a fractional generalization of the Fundamental Theorem of Calculus. We define the differential and integral vector operations. The fractional Green's, Stokes' and Gauss's theorems are formulated. The proofs of these theorems are realized for simplest regions. A fractional generalization of exterior differential calculus of differential forms is discussed. Fractional nonlocal Maxwell's equations and the corresponding fractional wave equations are considered
Wavelength-Dependent Effects in Maxwell Optics
Khan, S A
2002-01-01
We present a new formalism for light beam optics starting with an exact eight-dimensional matrix representation of the Maxwell equations. The Foldy-Wouthuysen iterative diagonalization technique is employed to obtain a Hamiltonian description for a system with varying refractive index. Besides, reproducing all the traditional quasiparaxial terms, this method leads to additional contributions, which are dependent on the wavelength, in the optical Hamiltonian. This alternate prescription to obtain the aberration expansion is applied to the axially symmetric graded index fiber. This results in the wavelength-dependent modifications of the paraxial behaviour and the aberration coefficients. Furthermore it predicts a wavelength-dependent image rotation. In the low wavelength limit our formalism reproduces the Lie algebraic formalism of optics. The Foldy-Wouthuysen technique employed by us is ideally suited for the Lie algebraic approach to optics. The present study further strengthens the close analogy between the...
Maxwell's equal area law for Lovelock Thermodynamics
Xu, Hao
2015-01-01
We present the construction of Maxwell's equal area law for the Guass-Bonnet AdS black holes in $d=5,6$ and third order Lovelock AdS black holes in $d=7,8$. The equal area law can be used to find the number and location of the points of intersection in the plots of Gibbs free energy, so that we can get the thermodynamically preferred solution which corresponds to the first order phase transition. We have the radius of the small and larger black holes in the phase transition which share the same Gibbs free energy. The latent heat can also be calculated. For the third order Lovelock AdS black holes in $d=8$, the first order phase transition can be found in $T_t
Incompressible Navier-Stokes equation from Einstein-Maxwell and Gauss-Bonnet-Maxwell theories
The dual fluid description for a general cutoff surface at radius r=rc outside the horizon in the charged AdS black brane bulk space-time is investigated, first in the Einstein-Maxwell theory. Under the non-relativistic long-wavelength expansion with parameter ε, the coupled Einstein-Maxwell equations are solved up to O(ε2). The incompressible Navier-Stokes equation with external force density is obtained as the constraint equation at the cutoff surface. For non-extremal black brane, the viscosity of the dual fluid is determined by the regularity of the metric fluctuation at the horizon, whose ratio to entropy density η/s is independent of both the cutoff rc and the black brane charge. Then, we extend our discussion to the Gauss-Bonnet-Maxwell case, where the incompressible Navier-Stokes equation with external force density is also obtained at a general cutoff surface. In this case, it turns out that the ratio η/s is independent of the cutoff rc but dependent on the charge density of the black brane.
Generalized gravitational entropy of interacting scalar field and Maxwell field
Wung-Hong Huang
2014-12-01
Full Text Available The generalized gravitational entropy proposed recently by Lewkowycz and Maldacena is extended to the interacting real scalar field and Maxwell field system. Using the BTZ geometry we first investigate the case of free real scalar field and then show a possible way to calculate the entropy of the interacting scalar field. Next, we investigate the Maxwell field system. We exactly solve the wave equation and calculate the analytic value of the generalized gravitational entropy. We also use the Einstein equation to find the effect of backreaction of the Maxwell field on the area of horizon. The associated modified area law is consistent with the generalized gravitational entropy.
Generalized gravitational entropy of interacting scalar field and Maxwell field
Huang, Wung-Hong
2014-12-01
The generalized gravitational entropy proposed recently by Lewkowycz and Maldacena is extended to the interacting real scalar field and Maxwell field system. Using the BTZ geometry we first investigate the case of free real scalar field and then show a possible way to calculate the entropy of the interacting scalar field. Next, we investigate the Maxwell field system. We exactly solve the wave equation and calculate the analytic value of the generalized gravitational entropy. We also use the Einstein equation to find the effect of backreaction of the Maxwell field on the area of horizon. The associated modified area law is consistent with the generalized gravitational entropy.
Generalized gravitational entropy of interacting scalar field and Maxwell field
Huang, Wung-Hong, E-mail: whhwung@mail.ncku.edu.tw
2014-12-12
The generalized gravitational entropy proposed recently by Lewkowycz and Maldacena is extended to the interacting real scalar field and Maxwell field system. Using the BTZ geometry we first investigate the case of free real scalar field and then show a possible way to calculate the entropy of the interacting scalar field. Next, we investigate the Maxwell field system. We exactly solve the wave equation and calculate the analytic value of the generalized gravitational entropy. We also use the Einstein equation to find the effect of backreaction of the Maxwell field on the area of horizon. The associated modified area law is consistent with the generalized gravitational entropy.
Can Maxwell's fish eye lens really give perfect imaging?
Sun, Fei; He, Sailing
2010-01-01
Both explicit analysis and FEM numerical simulation are used to analyze the field distribution of a line current in the so-called Maxwell's fish eye lens [bounded with a perfectly electrical conductor (PEC) boundary]. We show that such a 2D Maxwell's fish eye lens cannot give perfect imaging due to the fact that high order modes of the object field can hardly reach the image point in Maxwell's fish eye lens. If only zeroth order mode is excited, a good image of a sharp object may be achieved ...
Quantum Maxwell's Demon in Thermodynamic Cycles
Dong, H; Sun, C P
2010-01-01
We study the physical mechanism of Maxwell's Demon (MD) helping to do extra work in thermodynamic cycles, by describing measurement of position, insertion of wall and information erasing of MD in a quantum mechanical fashion. The heat engine is exemplified with one molecule confined in an infinitely deep square potential inserted with a movable solid wall, while the MD is modeled as a two-level system (TLS) for measuring and controlling the motion of the molecule. It is discovered that the the MD with quantum coherence or on a lower temperature than that of the heat bath of the particle would enhance the ability of the whole work substance formed by the system plus the MD to do work outside. This observation reveals that the role of the MD essentially is to drive the whole work substance being off equilibrium, or equivalently working with an effective temperature difference. The elaborate studies with this model explicitly reveal the effect of finite size off the classical limit or thermodynamic limit, which ...
Basics of averaging of the Maxwell equations
Chipouline, A; Tretyakov, S
2011-01-01
Volume or statistical averaging of the microscopic Maxwell equations (MEs), i.e. transition from microscopic MEs to their macroscopic counterparts, is one of the main steps in electrodynamics of materials. In spite of the fundamental importance of the averaging procedure, it is quite rarely properly discussed in university courses and respective books; up to now there is no established consensus about how the averaging procedure has to be performed. In this paper we show that there are some basic principles for the averaging procedure (irrespective to what type of material is studied) which have to be satisfied. Any homogenization model has to be consistent with the basic principles. In case of absence of this correlation of a particular model with the basic principles the model could not be accepted as a credible one. Another goal of this paper is to establish the averaging procedure for metamaterials, which is rather close to the case of compound materials but should include magnetic response of the inclusi...
Maxwell Equations as the One Photon Quantum Equation
Maxwell equations (Faraday and Ampere-Maxwell laws) can be presented as a three component equation in a way similar to the two component neutrino equation. However, in this case, the electric and magnetic Gauss's laws can not be derived from first principles. We have shown how all Maxwell equations can be derived simultaneously from first principles, similar to those which have been used to derive the Dirac relativistic electron equation. We have 'also- shown that equations for massless particles, derived by Dirac in 1936, lead to the same result. The complex wave function, being a linear combination of the electric and magnetic fields, is a locally measurable quantity. Therefore Maxwell equations should be used as a guideline for proper interpretations of quantum equations
Exact and almost exact solution to Vlasov-Maxwell system
Exact and almost exact solutions to the Vlasov-Maxwell systems describing a variety of plasma configurations with density, temperature and current gradients, are presented. Possible consequences of these solutions are also discussed. 6 refs., 8 figs
Complete Vector Spherical Harmonic Expansion for Maxwell's Equations
Lambert, R. H.
1978-01-01
Conventional expansions of solutions to Maxwell's equations in vector spherical harmonics apply only outside the sources. The complete solution, applying both inside and outside the sources, is given here. Harmonic time dependence is assumed. (Author/GA)
The magnetic dipole interaction in Einstein-Maxwell theory
Bonnor, W. B.
2002-01-01
I derive an exact, static, axially symmetric solution of the Einstein-Maxwell equations representing two massless magnetic dipoles, and compare it with the corresponding solution of Einstein's equations for two massless spinning particles (see gr-qc/0201094). I then obtain an exact stationary solution of the Einstein-Maxwell equations representing two massless spinning magnets in balance. The conclusion is that the spin-spin force is analogous to the force between two magnetic dipoles, but of...
Maxwell and Dirac theories as an already unified theory
Vaz, Jr., Jayme; Rodrigues, Jr., Waldyr A.
1995-01-01
In this paper we formulate Maxwell and Dirac theories as an already unified theory (in the sense of Misner and Wheeler). We introduce Dirac spinors as "Dirac square root" of the Faraday bivector, and use this in order to find a spinorial representation of Maxwell equations. Then we show that under certain circunstances this spinor equation reduces to an equation formally identical to Dirac equation. Finally we discuss certain conditions under which this equation can be really interpreted as D...
Hopkins in the Age of Maxwell Hopkins à l’époque de Maxwell
René Gallet
2005-01-01
Full Text Available Lorsque l’on veut situer l’œuvre de Hopkins dans son contexte scientifique, on a l’habitude de le faire uniquement par rapport au débat évolutionniste, ou même darwinien, comme dans l’ouvrage de référence de T. Zaniello, Hopkins in the Age of Darwin. Ceci présuppose une vision sélective de ce contexte où figure notamment une autre grande révolution scientifique, dans le domaine de la physique fondamentale. Le représentant le plus éminent en est J. C. Maxwell, chaînon essentiel entre Newton et Einstein. Dans ses textes, Hopkins lui-même s’est intéressé surtout à cette autre révolution scientifique, allant jusqu’à commencer un livre critique envers Light, ouvrage de Tait, physicien de renom et ami de Maxwell. Hopkins s’en prend plus à l’épistémologie idéaliste illustrée, selon le poète, par Tait, qu’à la pensée davantage matérialiste d’un Tyndall. La raison en est sans doute son attachement à un réalisme philosophique dont dépend la notion d’ « inscape ».
Yun, Min S.; Aretxaga, I.; Gurwell, M. A.; Hughes, D. H.; Montaña, A.; Narayanan, G.; Rosa-González, D.; Sánchez-Argüelles, D.; Schloerb, F. P.; Snell, R. L.; Vega, O.; Wilson, G. W.; Zeballos, M.; Chavez, M.; Cybulski, R.; Díaz-Santos, T.; De La Luz, V.; Erickson, N.; Ferrusca, D.; Gim, H. B.; Heyer, M. H.; Iono, D.; Pope, A.; Rogstad, S. M.; Scott, K. S.; Souccar, K.; Terlevich, E.; Terlevich, R.; Wilner, D.; Zavala, J. A.
2015-12-01
Measuring redshifted CO line emission is an unambiguous method for obtaining an accurate redshift and total cold gas content of optically faint, dusty starburst systems. Here, we report the first successful spectroscopic redshift determination of AzTEC J095942.9+022938 (`COSMOS AzTEC-1'), the brightest 1.1 mm continuum source found in the AzTEC/James Clerk Maxwell Telescope survey (Scott et al.), through a clear detection of the redshifted CO (4-3) and CO (5-4) lines using the Redshift Search Receiver on the Large Millimeter Telescope. The CO redshift of z = 4.3420 ± 0.0004 is confirmed by the detection of the redshifted 158 μm [C II] line using the Submillimeter Array. The new redshift and Herschel photometry yield LFIR = (1.1 ± 0.1) × 1013 L⊙ and SFR ≈ 1300 M⊙ yr-1. Its molecular gas mass derived using the ultraluminous infrared galaxy conversion factor is 1.4 ± 0.2 × 1011M⊙ while the total interstellar medium mass derived from the 1.1 mm dust continuum is 3.7 ± 0.7 × 1011M⊙ assuming Td = 35 K. Our dynamical mass analysis suggests that the compact gas disc (r ≈ 1.1 kpc, inferred from dust continuum and spectral energy distribution analysis) has to be nearly face-on, providing a natural explanation for the uncommonly bright, compact stellar light seen by the HST. The [C II] line luminosity L_[C II]= 7.8± 1.1 × 10^9 L_{⊙} is remarkably high, but it is only 0.04 per cent of the total IR luminosity. AzTEC COSMOS-1 and other high redshift sources with a spatially resolved size extend the tight trend seen between [C II]/FIR ratio and ΣFIR among IR-bright galaxies reported by Díaz-Santos et al. by more than an order of magnitude, supporting the explanation that the higher intensity of the IR radiation field is responsible for the `[C II] deficiency' seen among luminous starburst galaxies.
Taiwan Automated Telescope Network
Shuhrat Ehgamberdiev; Alexander Serebryanskiy; Antonio Jimenez; Li-Han Wang; Ming-Tsung Sun; Javier Fernandez Fernandez; Dean-Yi Chou
2010-01-01
A global network of small automated telescopes, the Taiwan Automated Telescope (TAT) network, dedicated to photometric measurements of stellar pulsations, is under construction. Two telescopes have been installed in Teide Observatory, Tenerife, Spain and Maidanak Observatory, Uzbekistan. The third telescope will be installed at Mauna Loa Observatory, Hawaii, USA. Each system uses a 9-cm Maksutov-type telescope. The effective focal length is 225 cm, corresponding to an f-ratio of 25. The field...
On the Correct Analysis of the Maxwell Distribution
Kalanov, Temur Z.
2006-04-01
The critical analysis of the Maxwell distribution is proposed. The main results of the analysis are as follows. (1) As is known, an experimental device for studying the Maxwell distribution consists of the following basic physical subsystems: (a) ideal molecular gas enclosed in a vessel (gas is in the equilibrium state); (b) molecule beam which is emitted from the small aperture of the vessel (the small aperture is a stochastic source of quantum particles). (2) The energy of the molecule of the beam does not represent random quantity, since molecules does not collide with each other. In this case, only the set of the monoenergetic molecules emitted by the stochastic source is a random quantity. This set is called a quantum gas. The probability pk that the quantum gas has the energy Enk is given by the Gibbs quantum canonical distribution: pk=p0,,-Enk / Enk T) . - T), k=0,;1,; where k is the number of molecules with energy En; T is temperature of the molecule in the vessel. (3) The average number of the molecules with energyEn represents the Planck distribution function: f=∑k=0^∞kpk ≡f(Planck). (4) In classical case, the expression Enf(Planck) represents the Maxwell distribution function: f(Maxwell)˜En,(Planck)˜v^2,;(-mv^2 / mv^2 2T) . - 2T). Consequently, the generally accepted statement that the Maxwell distribution function describes gas enclosed in a vessel is a logical error.
Fochesato, Ch. [CEA Bruyeres-le-Chatel, Dept. de Conception et Simulation des Armes, Service Simulation des Amorces, Lab. Logiciels de Simulation, 91 (France); Bouche, D. [CEA Bruyeres-le-Chatel, Dept. de Physique Theorique et Appliquee, Lab. de Recherche Conventionne, Centre de Mathematiques et Leurs Applications, 91 (France)
2007-07-01
The numerical solution of Maxwell equations is a challenging task. Moreover, the range of applications is very wide: microwave devices, diffraction, to cite a few. As a result, a number of methods have been proposed since the sixties. However, among all these methods, none has proved to be free of drawbacks. The finite difference scheme proposed by Yee in 1966, is well suited for Maxwell equations. However, it only works on cubical mesh. As a result, the boundaries of complex objects are not properly handled by the scheme. When classical nodal finite elements are used, spurious modes appear, which spoil the results of simulations. Edge elements overcome this problem, at the price of rather complex implementation, and computationally intensive simulations. Finite volume methods, either generalizing Yee scheme to a wider class of meshes, or applying to Maxwell equations methods initially used in the field of hyperbolic systems of conservation laws, are also used. Lastly, 'Discontinuous Galerkin' methods, generalizing to arbitrary order of accuracy finite volume methods, have recently been applied to Maxwell equations. In this report, we more specifically focus on the coupling of a Maxwell solver to a PIC (Particle-in-cell) method. We analyze advantages and drawbacks of the most widely used methods: accuracy, robustness, sensitivity to numerical artefacts, efficiency, user judgment. (authors)
Generalized Gravitational Entropy of Interacting Scalar Field and Maxwell Field
Huang, Wung-Hong
2014-01-01
The generalized gravitational entropy proposed by Lewkowycz and Maldacena in recent is extended to the interacting real scalar field and Maxwell field system. Using the BTZ geometry we first investigate the case of free real scalar field and then show a possible way to calculate the entropy of the interacting scalar field. Next, we investigate the Maxwell field system. We exactly solve the wave equation and calculate the analytic value of the generalized gravitational entropy. We also use the Einstein equation to find the effect of backreaction of the Maxwell field on the spacetime. The associated modified area law is consistent with the generalized gravitational entropy. Our investigations have not found the unexpected anomalous surface term.
LINEAR GRAVITY WAVES ON MAXWELL FLUIDS OF FINITE DEPTH
ZHANG Qinghe; SUN Yabin
2004-01-01
Linear surface gravity waves on Maxwell viscoelastic fluids with finite depth are studied in this paper. A dispersion equation describing the spatial decay of the gravity wave in finite depth is derived. A dimensionless memory (time) number θ is introduced. The dispersion equation for the pure viscous fluid will be a specific case of the dispersion equation for the viscoelastic fluid as θ = 0. The complex dispersion equation is numerically solved to investigate the dispersion relation. The influences of θ and water depth on the dispersion characteristics and wave decay are discussed. It is found that the role of elasticity for the Maxwell fluid is to make the surface gravity wave on the Maxwell fluid behave more like the surface gravity wave on the inviscid fluid.
A Derivation of Maxwell Equations in Quaternion Space
Christianto V.
2010-04-01
Full Text Available Quaternion space and its respective Quaternion Relativity (it also may be called as Rotational Relativity has been defined in a number of papers, and it can be shown that this new theory is capable to describe relativistic motion in elegant and straightforward way. Nonetheless there are subsequent theoretical developments which remains an open question, for instance to derive Maxwell equations in Q-space. Therefore the purpose of the present paper is to derive a consistent description of Maxwell equations in Q-space. First we consider a simplified method similar to the Feynman's derivation of Maxwell equations from Lorentz force. And then we present another derivation method using Dirac decomposition, introduced by Gersten (1999. Further observation is of course recommended in order to refute or verify some implication of this proposition.
A Derivation of Maxwell Equations in Quaternion Space
Smarandache F.
2010-04-01
Full Text Available Quaternion space and its respective Quaternion Relativity (it also may be called as Ro- tational Relativity has been defined in a number of papers, and it can be shown that this new theory is capable to describe relativistic motion in elegant and straightforward way. Nonetheless there are subsequent theoretical developments which remains an open question, for instance to derive Maxwell equations in Q-space. Therefore the purpose of the present paper is to derive a consistent description of Maxwell equations in Q-space. First we consider a simplified method similar to the Feynman’s derivation of Maxwell equations from Lorentz force. And then we present another derivation method using Dirac decomposition, introduced by Gersten (1998. Further observation is of course recommended in order to refute or verify some implication of this proposition.
Hamiltonian time integrators for Vlasov-Maxwell equations
Hamiltonian time integrators for the Vlasov-Maxwell equations are developed by a Hamiltonian splitting technique. The Hamiltonian functional is split into five parts, which produces five exactly solvable subsystems. Each subsystem is a Hamiltonian system equipped with the Morrison-Marsden-Weinstein Poisson bracket. Compositions of the exact solutions provide Poisson structure preserving/Hamiltonian methods of arbitrary high order for the Vlasov-Maxwell equations. They are then accurate and conservative over a long time because of the Poisson-preserving nature
Asymptotic freedom at short distances in Dilaton-Maxwell Electrodynamics
Kechkin, Oleg
2016-01-01
An effective potential is created for the dynamics of a test particle, which preserves dilatation symmetry for nonlinear static dilaton-Maxwell background. It is found that the central interaction in this theory is regular everywhere, and that the theory is asymptotically free at short distances and that it has a Coulomb properties at great distances from the source. It is shown that static and spherically symmetric source, behaves like a soliton: it has the finite energy characteristics that are inversely proportional to the dilaton-Maxwell coupling constant.
Post-Newtonian Approximation in Maxwell-Like Form
Kaplan, Jeff D; Thorne, Kip S
2008-01-01
The equations of the linearized first post-Newtonian approximation to general relativity are often written in "gravitoelectromagnetic" Maxwell-like form, since that facilitates physical intuition. This paper expresses the first post-Newtonian approximation, including all nonlinearities, in Maxwell-like form, focusing especially on the gravitational momentum and its conservation as expressed in terms of the Landau-Lifshitz pseudotensor. The authors and their colleagues are finding this formalism useful in developing physical intuition into numerical-relativity simulations of binary black holes with spin.
Rutten, R. J.; Hammerschlag, R.H.; Bettonvil, F.C.M.
2001-01-01
The Dutch Open Telescope is a new and novel optical solar telescope on La Palma. It aims at high resolution by combining an excel- lent site on La Palma with an open tower and an open telescope and leads the way to large-aperture high resolution telescopes. We brie y review the DOT principle, structure and goals. More information is found at the DOT website.
Krabbe, Alfred
2000-01-01
The SOFIA telescope as the heart of the observatory is a major technological challenge. I present an overview on the astro-nomical and scientific requirements for such a big airborne observatory and demonstrate the impact of these requirements on the layout of SOFIA, in particular on the telescope design as it is now. Selected components of the telescope will be de-scribed in their context and functionality. The current status of the telescope is presented.
Prestage, R. M.; Constantikes, K. T.; Hunter, T. R.; King, L. J.; Lacasse, R. J.; Lockman, F. J.; Norrod, R. D.
2009-08-01
The Robert C. Byrd Green Bank Telescope of the National Radio Astronomy Observatory is the world's premiere single-dish radio telescope operating at centimeter to long millimeter wavelengths. This paper describes the history, construction, and main technical features of the telescope.
Auto Adjusting Astronomical Telescope
Rohit R. Ghalsasi; Prof. N. D. Dhoot
2014-01-01
Astronomical telescope is powerful and basic tool for star or celestial observation. Here we proposed integrated system using Raspberry Pi for auto adjusting astronomical telescope. This integrated circuit helps to control stellar monitoring, stellar targeting, and tracking functions of telescope. Astro compass gives the direction of the celestial objects.
Bigongiari, Ciro
2005-01-01
MAGIC (Major Atmospheric Gamma Imaging Cherenkov telescope) is presently the largest ground-based gamma ray telescope. MAGIC has been taking data regularly since October 2004 at the Roque de los Muchachos Observatory on the island of La Palma. In this paper the MAGIC telescope status, its performances and some preliminary results on observed gamma ray sources are presented.
Auto Adjusting Astronomical Telescope
Rohit R. Ghalsasi
2014-04-01
Full Text Available Astronomical telescope is powerful and basic tool for star or celestial observation. Here we proposed integrated system using Raspberry Pi for auto adjusting astronomical telescope. This integrated circuit helps to control stellar monitoring, stellar targeting, and tracking functions of telescope. Astro compass gives the direction of the celestial objects.
ATST telescope mount: telescope of machine tool
Jeffers, Paul; Stolz, Günter; Bonomi, Giovanni; Dreyer, Oliver; Kärcher, Hans
2012-09-01
The Advanced Technology Solar Telescope (ATST) will be the largest solar telescope in the world, and will be able to provide the sharpest views ever taken of the solar surface. The telescope has a 4m aperture primary mirror, however due to the off axis nature of the optical layout, the telescope mount has proportions similar to an 8 meter class telescope. The technology normally used in this class of telescope is well understood in the telescope community and has been successfully implemented in numerous projects. The world of large machine tools has developed in a separate realm with similar levels of performance requirement but different boundary conditions. In addition the competitive nature of private industry has encouraged development and usage of more cost effective solutions both in initial capital cost and thru-life operating cost. Telescope mounts move relatively slowly with requirements for high stability under external environmental influences such as wind buffeting. Large machine tools operate under high speed requirements coupled with high application of force through the machine but with little or no external environmental influences. The benefits of these parallel development paths and the ATST system requirements are being combined in the ATST Telescope Mount Assembly (TMA). The process of balancing the system requirements with new technologies is based on the experience of the ATST project team, Ingersoll Machine Tools who are the main contractor for the TMA and MT Mechatronics who are their design subcontractors. This paper highlights a number of these proven technologies from the commercially driven machine tool world that are being introduced to the TMA design. Also the challenges of integrating and ensuring that the differences in application requirements are accounted for in the design are discussed.
Rainich theory for type D aligned Einstein-Maxwell solutions
Ferrando, Joan Josep; Sáez, Juan Antonio
2007-01-01
The original Rainich theory for the non-null Einstein-Maxwell solutions consists of a set of algebraic conditions and the Rainich (differential) equation. We show here that the subclass of type D aligned solutions can be characterized just by algebraic restrictions.
Kink shape solutions of the Maxwell-Lorentz system
Sørensen, Mads Peter; Webb, G.M.; Brio, M.;
2005-01-01
In the limit of high amplitude oscillating electromagnetic fields, a sequence of kink antikink shaped optical waves has been found in the Maxwell's equations coupled to a single Lorentz oscillator and with Kerr nonlinearity. The individual kinks and antikinks result from a traveling wave assumption...
Oral History of Postsecondary Access: Martha Maxwell, a Pioneer
Casazza, Martha E.; Bauer, Laura
2004-01-01
Truly a pioneer in the field of learning assistance and developmental education, Martha Maxwell has mentored hundreds, if not thousands, of professionals and students as well as authored a variety of reference shelf publications. Her career spanned 50 years. In her classic, Improving Student Learning Skills, she says there are seven persons named…
Galilean symmetry of maxwell's equations in classical electrodynamics
The study presented shows that the Galilean group, like the Lorentz group, is a group of exact symmetry of Maxwell's equation. The Galilean group differs in that, while the field transformations are linear and global in the relativistic case, they are nonlinear in the Galilean and, generally speaking, depend on the coordinates of the event through some weight functions
Galilean symmetry of Maxwell's equations in classical electrodynamics
Kotel'Nikov, G. A.
1985-08-01
It is shown that the Galilean group, like the Lorentz group, is a group of exact symmetry of Maxwell's equation. The Galilean group differs in that, while the field transformations are linear and global in the relativistic case, they are nonlinear in the Galilean and, generally speaking, depend on the coordinates of the event through some weight functions.
Ito terms and the Maxwell field on the lattice
If lattice renormalization effects are ignored and the number of space-time dimensions is less than four, it is explicitly shown that the effective continuum action for the Maxwell field does not contain the so-called Ito terms. As is known, the qualitative reason for this result is the flat character of the integration measure
Second order guiding-center Vlasov–Maxwell equations
Madsen, Jens
2010-01-01
Second order gyrogauge invariant guiding-center coordinates with strong E×B-flow are derived using the Lie transformation method. The corresponding Poisson bracket structure and equations of motion are obtained. From a variational principle the explicit Vlasov–Maxwell equations are derived...
Ball lens reflections by direct solution of Maxwell's equations
We calculate ball lens reflections, using the exact solution of Maxwell's equations for the scattering of a beam from a dielectric sphere. Our results are consistent to within 1 dB with measurements of backreflection to a single-mode fiber. We also calculate backreflection to an astigmatic spot laser diode. copyright 1995 Optical Society of America
Pollution free discretization of Maxwell's equations in terms of potentials
A 2D discretization of Maxwell's equations is studied in terms of the electromagnetic potentials using linear and cubic finite elements. The formulation is first analyzed with respect to the discrete dispersion properties to show that it is pollution free. It is then further applied to a simple cylindrical waveguide problem, showing good convergence to the analytical eigenfrequencies. (author) 6 figs., 13 refs
Introduction to Einstein-Maxwell equations and the Rainich conditions
Santos, Wytler Cordeiro dos
2016-01-01
The first results of Einstein-Maxwell equations established by Raincih in 1925 are therefore called the Raincih conditions. Later the result was rediscovered by Misner and Wheeler in 1957 and made the basis of their geometrodynamics. The present survey will consider didactically the curvature of spacetime attributed to an electromagnetic field with conceptual and calculational details.
Noncommutative geometry framework and the Feynman's proof of Maxwell equations
The main focus of the present work is to study Feynman's proof of the Maxwell equations using the NC geometry framework. To accomplish this task, we consider two kinds of noncommutativity formulations going along the same lines as Feynman's approach. This allows us to go beyond the standard case and discover non-trivial results. In fact, while the first formulation gives rise to the static Maxwell equations, the second formulation is based on the following assumption m[xj, x-dotk] = iℎδjk+imθjkf. The results extracted from the second formulation are more significant since they are associated to a non trivial θ-extension of the Bianchi-set of Maxwell equations. We find divθB = ηθ and (∂Bs/∂t) + εkjs(∂Ej/∂xk) = A1(d2f/dt2) + A2(df/dt) + A3, where ηθ, A1, A2 and A3 are local functions depending on the NC θ-parameter. The novelty of this proof in the NC space is revealed notably at the level of the corrections brought to the previous Maxwell equations. These corrections correspond essentially to the possibility of existence of magnetic charges sources that we can associate to the magnetic monopole since divθB=ηθ is not vanishing in general. (author)
Maxwell-Higgs equation on higher dimensional static curved spacetimes
In this paper we consider a class of solutions of Maxwell-Higgs equation in higher dimensional static curved spacetimes called Schwarzchild de-Sitter spacetimes. We obtain the general form of the electric fields and magnetic fields in background Schwarzchild de-Sitter spacetimes. However, determining the interaction between photons with the Higgs scalar fields is needed further studies
Incompressible Maxwell-Boussinesq approximation: Existence, uniqueness and shape sensitivity
Consiglieri, L.; Nečasová, Šárka; Sokolowski, J.
2009-01-01
Roč. 38, č. 4 (2009), s. 1193-1215. ISSN 0324-8569 R&D Projects: GA ČR GA201/05/0005; GA ČR GA201/08/0012 Institutional research plan: CEZ:AV0Z10190503 Keywords : Maxwell-Boussinesq approximation Subject RIV: BA - General Mathematics Impact factor: 0.378, year: 2009
Entanglement entropy of a Maxwell field on the sphere
Casini, Horacio
2015-01-01
We compute the logarithmic coefficient of the entanglement entropy on a sphere for a Maxwell field in $d=4$ dimensions. In spherical coordinates the problem decomposes into one dimensional ones along the radial coordinate for each angular momentum. We show the entanglement entropy of a Maxwell field is equivalent to the one of two identical massless scalars from which the mode of $l=0$ has been removed. This shows the relation $c^M_{\\log}=2 (c^S_{\\log}-c^{S_{l=0}}_{\\log})$ between the logarithmic coefficient in the entropy for a Maxwell field $c^M_{\\log}$, the one for a $d=4$ massless scalar $c_{\\log}^S$, and the logarithmic coefficient $c^{S_{l=0}}_{\\log}$ for a $d=2$ scalar with Dirichlet boundary condition at the origin. Using the accepted values for these coefficients $c_{\\log}^S=-1/90$ and $c^{S_{l=0}}_{\\log}=1/6$ we get $c^M_{\\log}=-16/45$, which coincides with Dowker's calculation, but does not match the coefficient $-\\frac{31}{45}$ in the trace anomaly for a Maxwell field. We have numerically evaluate...
How to obtain the covariant form of Maxwell's equations from the continuity equation
Heras, Jose A [Departamento de Ciencias Basicas, Universidad Autonoma Metropolitana, Unidad Azcapotzalco, Av. San Pablo No. 180, Col. Reynosa, 02200, Mexico D. F. (Mexico); Departamento de Fisica y Matematicas, Universidad Iberoamericana, Prolongacion Paseo de la Reforma 880, Mexico D. F. 01210 (Mexico)
2009-07-15
The covariant Maxwell equations are derived from the continuity equation for the electric charge. This result provides an axiomatic approach to Maxwell's equations in which charge conservation is emphasized as the fundamental axiom underlying these equations.
2012-10-26
... National Park Service Notice of Inventory Completion: Maxwell Museum of Anthropology, University of New... to be culturally affiliated with the human remains may contact the Maxwell Museum of Anthropology.... Heather Edgar, Maxwell Museum of Anthropology, MSC01 1050, University of New Mexico, Albuquerque, NM...
Mänd, Anu, 1968-
2008-01-01
Arvustus: Kreem, Juhan. Sketches of a Clerk. Pen-and-ink Drawings in the Margins of the Medieval Accoung Books of Reval (Tallinn). (Krems, 2006). Juhan Kreemi raamat käsitleb Tallinna rae keskaegsetes arveraamatutes leiduvaid sulejoonistusi. Autor on välja selgitanud nende, esmapilgul juhuslikena näivate joonistuste otstarbe ning püüdnud nende kaudu avada tolleaegsete linnaametnike mõttemalle
JWST Pathfinder Telescope Integration
Matthews, Gary W.; Kennard, Scott H.; Broccolo, Ronald T.; Ellis, James M.; Daly, Elizabeth A.; Hahn, Walter G.; Amon, John N.; Mt. Pleasant, Stephen M.; Texter, Scott; Atkinson, Charles B.; McKay, Andrew; Levi, Joshua; Keski-Kuha, Ritva; Feinberg, Lee
2015-01-01
The James Webb Space Telescope (JWST) is a 6.5m, segmented, IR telescope that will explore the first light of the universe after the big bang. In 2014, a major risk reduction effort related to the Alignment, Integration, and Test (AI&T) of the segmented telescope was completed. The Pathfinder telescope includes two Primary Mirror Segment Assemblies (PMSA's) and the Secondary Mirror Assembly (SMA) onto a flight-like composite telescope backplane. This pathfinder allowed the JWST team to assess the alignment process and to better understand the various error sources that need to be accommodated in the flight build. The successful completion of the Pathfinder Telescope provides a final integration roadmap for the flight operations that will start in August 2015.
Automated telescope scheduling
Johnston, Mark D.
1988-08-01
With the ever increasing level of automation of astronomical telescopes the benefits and feasibility of automated planning and scheduling are becoming more apparent. Improved efficiency and increased overall telescope utilization are the most obvious goals. Automated scheduling at some level has been done for several satellite observatories, but the requirements on these systems were much less stringent than on modern ground or satellite observatories. The scheduling problem is particularly acute for Hubble Space Telescope: virtually all observations must be planned in excruciating detail weeks to months in advance. Space Telescope Science Institute has recently made significant progress on the scheduling problem by exploiting state-of-the-art artificial intelligence software technology. What is especially interesting is that this effort has already yielded software that is well suited to scheduling groundbased telescopes, including the problem of optimizing the coordinated scheduling of more than one telescope.
JWST pathfinder telescope integration
Matthews, Gary W.; Kennard, Scott H.; Broccolo, Ronald T.; Ellis, James M.; Daly, Elizabeth A.; Hahn, Walter G.; Amon, John N.; Mt. Pleasant, Stephen M.; Texter, Scott; Atkinson, Charles B.; McKay, Andrew; Levi, Joshua; Keski-Kuha, Ritva; Feinberg, Lee
2015-08-01
The James Webb Space Telescope (JWST) is a 6.5m, segmented, IR telescope that will explore the first light of the universe after the big bang. In 2014, a major risk reduction effort related to the Alignment, Integration, and Test (AI and T) of the segmented telescope was completed. The Pathfinder telescope includes two Primary Mirror Segment Assemblies (PMSA's) and the Secondary Mirror Assembly (SMA) onto a flight-like composite telescope backplane. This pathfinder allowed the JWST team to assess the alignment process and to better understand the various error sources that need to be accommodated in the flight build. The successful completion of the Pathfinder Telescope provides a final integration roadmap for the flight operations that will start in August 2015.
Gillespie, Richard
2011-01-01
Erected at Melbourne Observatory in 1869, the telescope was the second largest in the world, designed to explore the nature of the nebulae in the southern skies. Richard Gillespie, head of the History and Technology department at the Melbourne museum has written an entertaining account of the telescope's extraordinary history and tells the story through an amazing cast of characters whose lives intersected with the telescope.
New Radio Telescope Makes First Scientific Observations
2001-05-01
The world's two largest radio telescopes have combined to make detailed radar images of the cloud-shrouded surface of Venus and of a tiny asteroid that passed near the Earth. The images mark the first scientific contributions from the National Science Foundation's (NSF) new Robert C. Byrd Green Bank Telescope in West Virginia, which worked with the NSF's recently-upgraded Arecibo telescope in Puerto Rico. The project used the radar transmitter on the Arecibo telescope and the huge collecting areas of both telescopes to receive the echoes. GBT-Arecibo Radar Image of Maxwell Montes on Venus "These images are the first of many scientific contributions to come from the Robert C. Byrd Green Bank Telescope, and a great way for it to begin its scientific career," said Paul Vanden Bout, director of the National Radio Astronomy Observatory (NRAO). "Our congratulations go to the scientists involved in this project as well as to the hard-working staffs at Green Bank and Arecibo who made this accomplishment possible," Vanden Bout added. To the eye, Venus hides behind a veil of brilliant white clouds, but these clouds can be penetrated by radar waves, revealing the planet's surface. The combination of the Green Bank Telescope (GBT), the world's largest fully-steerable radio telescope, and the Arecibo telescope, the world's most powerful radar, makes an unmatched tool for studying Venus and other solar-system bodies. "Having a really big telescope like the new Green Bank Telescope to receive the radar echoes from small asteroids that are really close to the Earth and from very distant objects like Titan, the large moon of Saturn, will be a real boon to radar studies of the solar system." said Cornell University professor Donald Campbell, leader of the research team. Ten years ago, the radar system on NASA's Magellan spacecraft probed though the clouds of Venus to reveal in amazing detail the surface of the Earth's twin planet. These new studies using the GBT and Arecibo, the
Structures of General Relativity in Dilaton-Maxwell Electrodynamics
Kechkin, Oleg V
2016-01-01
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 point-like sourse of the Coulomb type. It is shown that this source is characterized by asymptotical freedom of the electrostatic 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.
Notes on Stefan-Maxwell Equation versus Grahan's Diffusion Law
无
2000-01-01
Certain prerequisite information on the component fluxes is necessary for solution of the Stefan-Maxwell equation in multicomponent diffusion systems and the Graham's law of diffusion and effusion is often resorted for this purpose. This article addresses solution of the Stefan-Maxwell equation in binary gas systems and explores the necessary conditions for definite solution of concentration profiles and pertinent component fluxes. It is found that there are multiple solutions for component fluxes in contradiction to what specified by the Graham's law of diffusion. The theorem of minimum entropy production in the non-equilibrium thermodynamics is believed instructive in determining the stable steady state solution out of infinite multiple solutions possible under the specified conditions. It is suggested that only when the boundary condition of component concentration is symmetrical in an isothermal binary system, the counter-diffusion becomes equimolar. The Graham's law of diffusion seems not generally valid for the case of isothermal ordinary diffusion.
Incompressible Einstein–Maxwell fluids with specified electric fields
S Hansraj; S D Maharaj; T Mthethwa
2013-10-01
The Einstein–Maxwell equations describing static charged spheres with uniform density and variable electric field intensity are studied. The special case of constant electric field is also studied. The evolution of the model is governed by a hypergeometric differential equation which has a general solution in terms of special functions. Several classes of exact solutions are identified which may be considered as charged generalizations of the incompressible Schwarzschild interior model. An analysis of the physical features is undertaken for the uniform case. It is demonstrated that uniform density spheres with constant electric field intensity are not realizable with isotropic pressures. This highlights the necessity of studying the criteria for physical admissability of gravitating spheres in general relativity which are solutions to the Einstein–Maxwell equations.
Radiating black holes in Einstein-Maxwell-dilaton theory
Aniceto, Pedro; Rocha, Jorge V
2015-01-01
We construct exact, time-dependent, black hole solutions of Einstein-Maxwell-dilaton theory with arbitrary dilaton coupling, a. For a=1 this theory arises as the four-dimensional low-energy effective description of heterotic string theory. These solutions represent electrically charged, spherically symmetric black holes emitting or absorbing charged null dust and generalize the Vaidya and Bonnor-Vaidya solutions of general relativity and of Einstein-Maxwell theory, respectively. The a=1 case stands out as special, in the sense that it is the only choice of the coupling that allows for a time-dependent dilaton field in this class of solutions. As a by-product, we prove that an electrically charged black hole in this theory cannot be overcharged by bombarding it with a stream of electrically charged null dust. This provides an example of cosmic censorship observance in a string theory setting.
Computational modeling of femtosecond optical solitons from Maxwell's equations
Goorjian, Peter M.; Taflove, Allen; Joseph, Rose M.; Hagness, Susan C.
1992-01-01
An algorithm is developed that permits the direct time integration of full-vector nonlinear Maxwell's equations. This capability permits the modeling of both linear and nonlinear instantaneous and dispersive effects in the electric polarization in material media. The modeling of the optical carrier is retained. The fundamental innovation is to notice that it is possible to treat the linear and nonlinear convolution integrals, which describe the dispersion, as new dependent variables. A coupled system of nonlinear second-order ordinary differential equations can then be derived for the linear and nonlinear convolution integrals, by differentiating them in the time domain. These equations, together with Maxwell's equations, are solved to determine the electromagnetic fields in nonlinear dispersive media. Results are presented of calculations in one dimension of the propagation and collision of femtosecond electromagnetic solitons that retain the optical carrier, taking into account as the Kerr and Raman interactions.
Generalized kinetic Maxwell type models of granular gases
Bobylev, A V; Gamba, I M
2009-01-01
We consider generalizations of kinetic granular gas models given by Boltzmann equations of Maxwell type. These type of models for non-linear elastic or inelastic interactions, have many applications in physics, dynamics of granular gases, economy, etc. We present the problem and develop its form in the space of characteristic functions, i.e. Fourier transforms of probability measures, from a very general point of view, including those with arbitrary polynomial non-linearities and in any dimension space. We find a whole class of generalized Maxwell models that satisfy properties that characterize the existence and asymptotic of dynamically scaled or self-similar solutions, often referred as {\\em homogeneous cooling states}. Of particular interest is a concept interpreted as an operator generalization of usual Lipschitz conditions which allows to describe the behavior of solutions to the corresponding initial value problem. In particular, we present, in the most general case, existence of self similar solutions...
Locating radiating sources for Maxwell's equations using the approximate inverse
We present a new approach to solve inverse source problems for the three-dimensional time-harmonic Maxwell's equations using boundary measurements of the radiated fields. The modelling is based on the formulation as a system of integro-differential equations for the electric field. We introduce a method to recast the intertwined vector equations of Maxwell into decoupled scalar problems. The method of the approximate inverse is used both for regularization and the development of fast algorithms. We make the analysis of the method when data are collected on a spherical setting around the object. Based on the singular value decomposition, we study the smoothing properties for the underlying operator and derive an error estimate for the regularized solution in a Sobolev-space framework. Numerical simulations illustrate the efficiency and practical usefulness of the developed method
Reflection-free finite volume Maxwell's solver for adaptive grids
Elkina, Nina
2015-01-01
We present a non-staggered method for the Maxwell equations in adaptively refined grids. The code is based on finite volume central scheme that preserves in a discrete form both divergence-free property of magnetic field and the Gauss law. High spatial accuracy is achieved with help of non-oscillatory extrema preserving piece-wise or piece-wise-quadratic reconstructions. The semi-discrete equations are solved by implicit-explicit Runge-Kutta method. The new adaptive grid Maxwell's solver is examined based on several 1d examples, including the an propagation of a Gaussian pulse through vacuum and partially ionised gas. Two-dimensional extension is tested with a Gaussian pulse incident on dielectric disc. Additionally, we focus on testing computational accuracy and efficiency.
The effective action in Einstein-Maxwell theory
Considerable work has been done on the one-loop effective action in combined electromagnetic and gravitational fields, particularly as a tool for determining the properties of light propagation in curved space. After a short review of previous work, I will present some recent results obtained using the worldline formalism. In particular, I will discuss various ways of generalizing the QED Euler-Heisenberg Lagrangians to the Einstein-Maxwell case.
Basics of averaging of the Maxwell equations for bulk materials
Chipouline, A.; Simovski, C.; Tretyakov, S.
2012-01-01
Volume or statistical averaging of the microscopic Maxwell equations (MEs), i.e. transition from microscopic MEs to their macroscopic counterparts, is one of the main steps in electrodynamics of materials. In spite of the fundamental importance of the averaging procedure, it is quite rarely properly discussed in university courses and respective books; up to now there is no established consensus about how the averaging procedure has to be performed. In this paper we show that there are some b...
Incompressible Maxwell-Boussinesq approximation: Existence, uniqueness and shape sensitivity
Consiglieri, Luisa; Necasova, Sarka; Sokolowski, Jan
2009-01-01
We prove the existence and uniqueness of weak solutions to the variational formulation of the Maxwell-Boussinesq approximation problem. Some further regularity in $W^{1,2+\\delta}$, $\\delta>0$, is obtained for the weak solutions. The shape sensitivity analysis by the boundary variations technique is performed for the weak solutions. As a result, the existence of the strong material derivatives for the weak solutions of the problem is shown. The result can be used to establish the shape differe...
The effective action in Einstein-Maxwell theory
Bastianelli, Fiorenzo; Davila, Jose Manuel; Schubert, Christian
2008-01-01
Considerable work has been done on the one-loop effective action in combined electromagnetic and gravitational fields, particularly as a tool for determining the properties of light propagation in curved space. After a short review of previous work, I present some recent results obtained using the worldline formalism. In particular, I will discuss various ways of generalizing the QED Euler-Heisenberg Lagrangian to the Einstein-Maxwell case.
Charged Particle Tunnels from the Einstein-Maxwell Black Hole
Chen, Deyou; Yang, Shuzheng
Considering the self-gravitation interaction and the unfixed background space-time, we study the Hawking radiation of the Einstein-Maxwell-Dilaton-Axion (EMDA) black hole by the radial geodesic method and the Hamilton-Jacobi method. Both sets of results agree with Parikh and Wilczek's and show that the actual radiation spectrum deviates from the purely thermal one and the tunneling probability is related to the change of Bekenstein-Hawking entropy, which satisfies an underlying unitary theory.
Class of Einstein-Maxwell-Dilaton-Axion Space-Times
Matos, Tonatiuh; Sanchez-Sanchez, Ruben; Wiederhold, Petra
2009-01-01
We use the harmonic maps ansatz to find exact solutions of the Einstein-Maxwell-Dilaton-Axion (EMDA) equations. The solutions are harmonic maps invariant to the symplectic real group in four dimensions $Sp(4,\\Rreal)\\sim O(5)$. We find solutions of the EMDA field equations for the one and two dimensional subspaces of the symplectic group. Specially, for illustration of the method, we find space-times that generalise the Schwarzschild solution with dilaton, axion and electromagnetic fields.
Algorithm development for Maxwell's equations for computational electromagnetism
Goorjian, Peter M.
1990-01-01
A new algorithm has been developed for solving Maxwell's equations for the electromagnetic field. It solves the equations in the time domain with central, finite differences. The time advancement is performed implicitly, using an alternating direction implicit procedure. The space discretization is performed with finite volumes, using curvilinear coordinates with electromagnetic components along those directions. Sample calculations are presented of scattering from a metal pin, a square and a circle to demonstrate the capabilities of the new algorithm.
Comment on 'Perfect drain for the Maxwell fish eye lens'
Sun, Fei
2012-01-01
The non-magnetic loss material has been proposed (2011 New J. Phys. 13 023038) to mimic a passive perfect drain in the Maxwell's fish eye lens (MFL). In this comment, we argue that this passive medium can only be treated as a perfect absorber which can totally absorb all incident radiation without scattering by it, but it cannot mimic a delta function at the image point. As a result, this passive medium cannot help to achieve a perfect focusing in MFL.
Spline discrete differential forms. Application to Maxwell' s equations.
Back, Aurore; Sonnendrücker, Eric
2011-01-01
We construct a new set of discrete differential forms based on B-splines of arbitrary degree as well as an associated Hodge operator. The theory is first developed in 1D and then extended to multi-dimension using tensor products. We link our discrete differential forms with the theory of chains and cochains. The spline discrete differential forms are then applied to the numerical solution of Maxwell's equations.
A sharp stability criterion for the Vlasov-Maxwell system
Lin, Zhiwu; Strauss, Walter
2007-01-01
We consider the linear stability problem for a 3D cylindrically symmetric equilibrium of the relativistic Vlasov-Maxwell system that describes a collisionless plasma. For an equilibrium whose distribution function decreases monotonically with the particle energy, we obtained a linear stability criterion in our previous paper. Here we prove that this criterion is sharp; that is, there would otherwise be an exponentially growing solution to the linearized system. Therefore for the class of symm...
Super-resolution Properties of the Maxwell Fish-Eyes
Grabovičkić, Dejan; Gonzalez Lopez, Juan Carlos; Miñano Dominguez, Juan Carlos; Benitez Gimenez, Pablo
2011-01-01
In this paper we present an analysis that shows the Maxwell Fish Eye (MFE) only has super-resolution property for some particular frequencies (for other frequencies, the MFE behaves as conventional imaging lens). These frequencies are directly connected with the Schumann resonance frequencies of spherical symmetric systems. The analysis have been done using a thin spherical waveguide (two concentric spheres with constant index between them), which is a dual form of the MFE (the ele...
Classification of local conservation laws of Maxwell's equations
Anco, Stephen C.; Pohjanpelto, Juha
2001-01-01
A complete and explicit classification of all independent local conservation laws of Maxwell's equations in four dimensional Minkowski space is given. Besides the elementary linear conservation laws, and the well-known quadratic conservation laws associated to the conserved stress-energy and zilch tensors, there are also chiral quadratic conservation laws which are associated to a new conserved tensor. The chiral conservation laws possess odd parity under the electric-magnetic duality transfo...
Rheological properties for inelastic Maxwell mixtures under shear flow
Garzo, Vicente; Trizac, Emmanuel
2009-01-01
The Boltzmann equation for inelastic Maxwell models is considered to determine the rheological properties in a granular binary mixture in the simple shear flow state. The transport coefficients (shear viscosity and viscometric functions) are {\\em exactly} evaluated in terms of the coefficients of restitution, the (reduced) shear rate and the parameters of the mixture (particle masses, diameters and concentration). The results show that in general, for a given value of the coefficients of rest...
Adaptation of Galilean transformations to serve Maxwell's equations of electromagnetism
Gyurov, Anton; Tokin, Radina
2011-01-01
In this case study we aim to investigate the important milestones in the incorporation of Maxwell's laws of electromagnetism in Newtonian relativity. Theoretical research has been conducted upon the work of Voigt, Poincare and Lorentz, in the field of mathematical transformations between inertial frames. The development of these transformations is linked to Newton's and Einstein's relativity principles. Although accepting the constancy of speed of light and developing transformations in contr...
A Re-Examination of Maxwell's Electrodynamics Equations
Dunning-Davies J.
2015-10-01
Full Text Available It is pointed out that the usual derivation of the well-known Maxwell electromagnetic equations holds only for a medium at rest. A way in which the equations may be modified for the case when the mean flow of the medium is steady and uniform is proposed. The implication of this for the problem of the origin of planetary magnetic fields is discussed.
Maxwell electromagnetism as an emergent phenomenon in condensed matter.
Rehn, J; Moessner, R
2016-08-28
The formulation of a complete theory of classical electromagnetism by Maxwell is one of the milestones of science. The capacity of many-body systems to provide emergent mini-universes with vacua quite distinct from the one we inhabit was only recognized much later. Here, we provide an account of how simple systems of localized spins manage to emulate Maxwell electromagnetism in their low-energy behaviour. They are much less constrained by symmetry considerations than the relativistically invariant electromagnetic vacuum, as their substrate provides a non-relativistic background with even translational invariance broken. They can exhibit rich behaviour not encountered in conventional electromagnetism. This includes the existence of magnetic monopole excitations arising from fractionalization of magnetic dipoles; as well as the capacity of disorder, by generating defects on the lattice scale, to produce novel physics, as exemplified by topological spin glassiness or random Coulomb magnetism.This article is part of the themed issue 'Unifying physics and technology in light of Maxwell's equations'. PMID:27458263
On subwavelength imaging of Maxwell's fish eye lens
Sun, Fei
2010-01-01
Both explicit analysis and FEM numerical simulation are used to analyze the field distribution of a line current in the so-called Maxwell's fish eye lens, which has been claimed recently to be able to achieve perfect imaging. We show that such a Maxwell's fish eye lens cannot give perfect imaging due to the fact that high order modes of the object field can hardly reach the image point in the Maxwell's fish eye. If only zero order mode is excited, a subwavelength image can be achieved, however, its spot-size is larger than the spot size of the source field. The image resolution is determined by the field spot size of the image corresponding to the zeroth order component of the object field. Our explicit analysis consists very well with the FEM results for a modified fish eye bounded with perfectly electrical conductor (PEC). Explicit condition is given for achieving a subwavelength image. When this condition is not satisfied, a single line current source may give multiple image spots.
Can Maxwell's fish eye lens really give perfect imaging?
Sun, Fei
2010-01-01
Both explicit analysis and FEM numerical simulation are used to analyze the field distribution of a line current in the so-called Maxwell's fish eye lens [bounded with a perfectly electrical conductor (PEC) boundary]. We show that such a 2D Maxwell's fish eye lens cannot give perfect imaging due to the fact that high order modes of the object field can hardly reach the image point in Maxwell's fish eye lens. If only zeroth order mode is excited, a good image of a sharp object may be achieved in some cases, however, its spot-size is larger than the spot size of the initial object field. The image resolution is determined by the field spot size of the image corresponding to the zeroth order component of the object field. Our explicit analysis consists very well with the FEM results for a fish eye lens. Time-domain simulation is also given to verify our conclusion. Multi-point images for a single object point are also demonstrated.
On subwavelength imaging with Maxwell's fish eye lens
Sun, Fei
2010-01-01
Both explicit analysis and FEM numerical simulation are used to analyze the field distribution of a line current in the so-called Maxwell's fish eye lens [bounded with a perfectly electrical conductor (PEC) boundary]. We show that such a 2D Maxwell's fish eye lens cannot give perfect imaging due to the fact that high order modes of the object field can hardly reach the image point in Maxwell's fish eye lens. If only zeroth order mode is excited, a subwavelength image of a sharp object may be achieved in some cases, however, its spot-size is larger than the spot size of the initial object field. The image resolution is determined by the field spot size of the image corresponding to the zeroth order component of the object field. Our explicit analysis consists very well with the FEM results for a fish eye lens. Time-domain simulation is also given to verify our conclusion. Multi-point imaging for a single object point is also demonstrated.
The Maxwell-Stefan description of binary diffusion
Bringuier, E.
2013-09-01
The paper deals with interdiffusion in a two-component fluid (also called binary or mutual diffusion) near isothermal equilibrium. The historical approach of Maxwell and Stefan, developed in an ideal gaseous mixture, is updated by introducing the chemical potentials of the components subsequently devised by Gibbs, which enable one to implement the Maxwell-Stefan picture of interdiffusion in an arbitrary fluid mixture. The pattern of the interdiffusion law reduces to Fick's in the high-dilution limit, but care should be taken of the reference frame in which the laws of diffusion are written. For a third-year university student, the assets of the modern Maxwell-Stefan description, besides its simplicity and inborn connection with thermodynamics, are (i) manifest Galilean invariance (the principle of relativity of motion); (ii) straightforward compatibility with fluid dynamics; and (iii) simple generalization to a multicomponent fluid in future, graduate-level studies. The value of the mutual-diffusion coefficient, which is not given by the macroscopic description, was calculated by Stefan in an ideal gaseous mixture and found to be independent of the composition. That independence is often observed in real mixtures and is taken as evidence against the mean-free-path account of diffusion. Yet a mixture of components of disparate masses shows a dependence of the mutual-diffusion coefficient on its composition, and we examine why Stefan's calculation can be invalid for this mixture.
Maxwell boundary conditions impose non-Lindblad master equation
Bamba, Motoaki
2016-01-01
From the Hamiltonian connecting the inside and outside of an Fabry-Perot cavity, which is derived from the Maxwell boundary conditions at a mirror of the cavity, a master equation of a non-Lindblad form is derived when the cavity embeds matters, although we can transform it to the Lindblad form by performing the rotating-wave approximation to that Hamiltonian. We calculate absorption spectra by these Lindblad and non-Lindblad master equations and also by the Maxwell boundary conditions in framework of the classical electrodynamics, which we consider the most reliable approach. We found that, compared to the Lindblad master equation, the absorption spectra by the non-Lindblad one agree better with those by the Maxwell boundary conditions. Although the discrepancy is highlighted only in the ultra-strong light-matter interaction regime with a relatively large broadening, the master equation of the non-Lindblad form is preferable rather than of the Lindblad one for pursuing the consistency with the classical elec...
Druskin, V.; Knizhnerman, L.
1994-12-31
The authors solve the Cauchy problem for an ODE system Au + {partial_derivative}u/{partial_derivative}t = 0, u{vert_bar}{sub t=0} = {var_phi}, where A is a square real nonnegative definite symmetric matrix of the order N, {var_phi} is a vector from R{sup N}. The stiffness matrix A is obtained due to semi-discretization of a parabolic equation or system with time-independent coefficients. The authors are particularly interested in large stiff 3-D problems for the scalar diffusion and vectorial Maxwell`s equations. First they consider an explicit method in which the solution on a whole time interval is projected on a Krylov subspace originated by A. Then they suggest another Krylov subspace with better approximating properties using powers of an implicit transition operator. These Krylov subspace methods generate optimal in a spectral sense polynomial approximations for the solution of the ODE, similar to CG for SLE.
Massie, Norbert A.; Oster, Yale
1992-01-01
A large effective-aperture, low-cost optical telescope with diffraction-limited resolution enables ground-based observation of near-earth space objects. The telescope has a non-redundant, thinned-aperture array in a center-mount, single-structure space frame. It employs speckle interferometric imaging to achieve diffraction-limited resolution. The signal-to-noise ratio problem is mitigated by moving the wavelength of operation to the near-IR, and the image is sensed by a Silicon CCD. The steerable, single-structure array presents a constant pupil. The center-mount, radar-like mount enables low-earth orbit space objects to be tracked as well as increases stiffness of the space frame. In the preferred embodiment, the array has elemental telescopes with subaperture of 2.1 m in a circle-of-nine configuration. The telescope array has an effective aperture of 12 m which provides a diffraction-limited resolution of 0.02 arc seconds. Pathlength matching of the telescope array is maintained by an electro-optical system employing laser metrology. Speckle imaging relaxes pathlength matching tolerance by one order of magnitude as compared to phased arrays. Many features of the telescope contribute to substantial reduction in costs. These include eliminating the conventional protective dome and reducing on-site construction activites. The cost of the telescope scales with the first power of the aperture rather than its third power as in conventional telescopes.
Athermal laser launch telescopes
Kamphues, F.G.; Henselmans, R.; Rijnveld, N.; Lemmen, M.H.J.; Doelman, N.J.; Nijkerk, M.D.
2011-01-01
ESO has developed a concept for a compact laser guide star unit for use in future Adaptive Optics (AO) systems. A small powerful laser is combined with a telescope that launches the beam, creating a single modular unit that can be mounted directly on a large telescope. This approach solves several o
1990-02-01
An overview of the mission of the Hubble Space Telescope, a joint project between NASA and the European Space Agency which will be used to study deep space, as well as our solar system is presented. The video contains animations depicting the Hubble Space Telescope in orbit, as well as footage of scientists at the Space Telescope Science Institute making real time observations. The images Hubble acquires will be downloaded into a database that contains images of over 19,000,0000 celestial objects called the Star Catalog.
Rutten, R. J.; Hammerschlag, R.H.; Bettonvil, F.C.M.
2001-01-01
The Utrecht Open Tower Telescope, recently renamed into \\Dutch Open Telescope", is now being installed at the Roque de los Muchachos Observatory on La Palma (Fig. 1). Like THEMIS, the DOT is a solar telescope of novel design, is located at a superior site, aims at high spatial resolution, is suited to polarimetry, has been long in the making, and should start its scientic career in 1997. Unlike THEMIS, the DOT has no dome, no vacuum enclosure, no post-focus equipment, and no long-term funding.
Rutten, R. J.; Hammerschlag, R.H.; Bettonvil, F.C.M.
2001-01-01
The Utrecht Open Tower Telescope, recently renamed into "Dutch Open Telescope", is now being installed at the Roque de los Muchachos Observatory on La Palma (Fig. 1). Like THEMIS, the DOT is a solar telescope of novel design, is located at a superior site, aims at high spatial resolution, is suited to polarimetry, has been long in the making, and should start its scientific career in 1997. Unlike THEMIS, the DOT has no dome, no vacuum enclosure, no post-focus equipment, and no long-term funding.
The Remote Maxwell Demon as Energy Down-Converter
Hossenfelder, S.
2016-04-01
It is demonstrated that Maxwell's demon can be used to allow a machine to extract energy from a heat bath by use of information that is processed by the demon at a remote location. The model proposed here effectively replaces transmission of energy by transmission of information. For that we use a feedback protocol that enables a net gain by stimulating emission in selected fluctuations around thermal equilibrium. We estimate the down conversion rate and the efficiency of energy extraction from the heat bath.
Wormhole Solutions in the Presence of Nonlinear Maxwell Field
S. H. Hendi
2014-01-01
Full Text Available In generalizing the Maxwell field to nonlinear electrodynamics, we look for the magnetic solutions. We consider a suitable real metric with a lower bound on the radial coordinate and investigate the properties of the solutions. We find that in order to have a finite electromagnetic field near the lower bound, we should replace the Born-Infeld theory with another nonlinear electrodynamics theory. Also, we use the cut-and-paste method to construct wormhole structure. We generalize the static solutions to rotating spacetime and obtain conserved quantities.
Godunov scheme for Maxwell's equations with Kerr nonlinearity
Aregba-Driollet, Denise
2014-01-01
We study the Godunov scheme for a nonlinear Maxwell model arising in nonlinear optics, the Kerr model. This is a hyperbolic system of conservation laws with some eigenvalues of variable multiplicity, neither genuinely nonlinear nor linearly degenerate. The solution of the Riemann problem for the full-vector 6x6 system is constructed and proved to exist for all data. This solution is compared to the one of the reduced Transverse Magnetic model. The scheme is implemented in one and two space di...
Perfect drain for the Maxwell Fish Eye lens
Gonzalez Lopez, Juan Carlos; Benitez Gimenez, Pablo; Miñano Dominguez, Juan Carlos
2010-01-01
Perfect imaging of electromagnetic waves using the Maxwell ﬁsh eye (MFE) requires a new concept: a point called the perfect drain that we shall call the perfect point drain. From the mathematical point of view, a perfect point drain is just like an ideal point source, except that it drains power from the electromagnetic ﬁeld instead of generating it. We introduce here the perfect drain for the MFE as a dissipative region of non-zero size that completely drains the power from the point source....
SIM(1)-VSR Maxwell-Chern-Simons electrodynamics
Bufalo, R.
2016-06-01
In this paper we propose a very special relativity (VSR)-inspired generalization of the Maxwell-Chern-Simons (MCS) electrodynamics. This proposal is based upon the construction of a proper study of the SIM (1)-VSR gauge-symmetry. It is shown that the VSR nonlocal effects present a significant and healthy departure from the usual MCS theory. The classical dynamics is analysed in full detail, by studying the solution for the electric field and static energy for this configuration. Afterwards, the interaction energy between opposite charges is derived and we show that the VSR effects play an important part in obtaining a (novel) finite expression for the static potential.
Maxwell Equations Solution Using Spin-weighted Spherical Harmonics
The electric and magnetic fields in vacuum, in a source-free region, are divergenceless and, if it is assumed that they have a harmonic time dependence with frequency ω, they satisfy the vector Helmholtz equation. We can then solve the Helmholtz equation using the spin-weighted spherical harmonics. However a lot of constants produced in the process have to be determined. In this work we find these constants corresponding to the electric and magnetic fields, i.e. we obtain the multipole solution of Maxwell equations in a rigorous manner. In addition we give an Expression for the vector potential in terms of the multipole moments
Introduction to the Fock quantization of the Maxwell field
In this article we give an introduction to the Fock quantization of the Maxwell field. At the classical level, we treat the theory in both the covariant and canonical phase space formalisms. The approach is general since we consider arbitrary (globally-hyperbolic) space-times. The Fock quantization is shown to be equivalent to the definition of a complex structure on the classical phase space. As examples, we consider stationary space-times as well as ordinary Minkowski space-time. The account is pedagogical in spirit and is tailored to beginning graduate students. The paper is self contained and is intended to fill an existing gap in the literature. (Author)
Small amplitude solitary waves in the Dirac-Maxwell system
Comech, Andrew; Stuart, David
2012-01-01
We study nonlinear bound states, or solitary waves, in the Dirac-Maxwell system proving the existence of solutions in which the Dirac wave function is of the form $\\phi(x,\\omega)e^{-i\\omega t}$, $\\omega\\in(-m,\\omega_*)$, with some $\\omega_*>-m$, such that $\\phi_\\omega\\in H^1(\\R^3,\\C^4)$, $\\Vert\\phi_\\omega\\Vert^2_{L^2}=O(m-|\\omega|)$, and $\\Vert\\phi_\\omega\\Vert_{L^\\infty}=O(m-|\\omega|)$. The method of proof is an implicit function theorem argument based on an identification of the nonrelativis...
SIM$(1)$--VSR Maxwell-Chern-Simons electrodynamics
Bufalo, R
2016-01-01
In this paper we propose a very special relativity (VSR)-inspired generalization of the Maxwell-Chern-Simons (MCS) electrodynamics. This proposal is based upon the construction of a proper study of the SIM$(1)$--VSR gauge-symmetry. It is shown that the VSR nonlocal effects present a significant and health departure from the usual MCS theory. The classical dynamics is analysed in full detail, by studying the solution for the electric field and static energy for this configuration. Afterwards, the interaction energy between opposite charges are derived and we show that the VSR effects play an important part in obtaining a (novel) finite expression for the static potential.
The free energy of Maxwell-Vlasov equilibria
A previously derived expression for the energy of arbitrary perturbations about arbitrary Vlasov-Maxwell equilibria is transformed into a very compact form. The new form is also obtained by a canonical transformation method for solving Vlasov's equation, which is based on Lie group theory. This method is simpler than the one used before and provides better physical insight. Finally a procedure is presented for determining the existence of negative-energy modes. In this context the question of why there is an accessibility constraint for the particles, but not for the fields, is discussed. 16 refs
A Modified Szilard's Engine: Measurement, Information, and Maxwell's Demon
Michael Devereux
2004-03-01
Full Text Available Abstract: Using an isolated measurement process, I've calculated the effect measurement has on entropy for the multi-cylinder Szilard engine. This calculation shows that the system of cylinders possesses an entropy associated with cylinder total energy states, and that it records information transferred at measurement. Contrary to other's results, I've found that the apparatus loses entropy due to measurement. The Second Law of Thermodynamics may be preserved if Maxwell's demon gains entropy moving the engine partition.
Viscoelastic Modelling of Solid Rocket Propellants using Maxwell Fluid Model
Himanshu Shekhar
2010-07-01
Full Text Available Maxwell fluid model consisting of a spring and a dashpot in series is applied for viscoelastic characterisation of solid rocket propellants. Suitable values of spring constant and damping coefficient wereemployed by least square variation of errors for generation of complete stress-strain curve in uniaxial tensile mode for case-bonded solid propellant formulations. Propellants from the same lot were tested at different strain rates. It was observed that change in spring constant, representing elastic part was very small with strain rate but damping constant varies significantly with variation in strain rate. For a typical propellant formulation, when strain rate was raised from 0.00037/s to 0.185/s, spring constant K changed from 5.5 MPato 7.9 MPa, but damping coefficient D was reduced from 1400 MPa-s to 4 MPa-s. For all strain rates, stress-strain curve was generated using Maxwell model and close matching with actual test curve was observed.This indicates validity of Maxwell fluid model for uniaxial tensile testing curves of case-bonded solid propellant formulations. It was established that at higher strain rate, damping coefficient becomes negligible as compared to spring constant. It was also observed that variation of spring constant is logarithmic with strain rate and that of damping coefficient follows power law. The correlation coefficients were introduced to ascertain spring constants and damping coefficients at any strain rate from that at a reference strain rate. Correlationfor spring constant needs a coefficient H, which is function of propellant formulation alone and not of test conditions and the equation developeds K2 = K1 + H ´ ln{(de2/dt/(de1/dt}. Similarly for damping coefficient D also another constant S is introduced and prediction formula is given by D2 = D1 ´ {(de2/dt/(de1/dt}S.Evaluating constants H and S at different strain rates validate this mathematical formulation for differentpropellant formulations
Derivation of special relativity from Maxwell and Newton.
Dunstan, D J
2008-05-28
Special relativity derives directly from the principle of relativity and from Newton's laws of motion with a single undetermined parameter, which is found from Faraday's and Ampère's experimental work and from Maxwell's own introduction of the displacement current to be the -c(-2) term in the Lorentz transformations. The axiom of the constancy of the speed of light is quite unnecessary. The behaviour and the mechanism of the propagation of light are not at the foundations of special relativity. PMID:18218595
Time-harmonic Maxwell equations with asymptotically linear polarization
Qin, Dongdong; Tang, Xianhua
2016-06-01
This paper is concerned with the following time-harmonic semilinear Maxwell equation: nabla× (nabla× u)+λ u=f(x,u), &in Ω ν × u=0, &on partialΩ, where {Ωsubset {R}3} is a bounded, convex domain and {ν : partial Ωto {R}3} is the exterior normal. Motivated by recent work of Bartsch and Mederski and based on some observations and new techniques, we study above equation by developing the generalized Nehari manifold method. Particularly, existence of ground-state solutions of Nehari-Pankov type for the equation is established with asymptotically linear nonlinearity.
Traffic restrictions on Routes Bloch, Maxwell and Bohr
IT Department
2008-01-01
Excavation and pipework is being carried out in the framework of the transfer of the waste water treatment plant for the effluents from the surface treatment workshops from Building 254 to Building 676, currently under construction. This work may encroach onto Routes Bloch, Maxwell and Bohr and disrupt the flow of traffic. Users are requested to comply with the road signs that will be erected. The work is expected to last until the beginning of December 2008. Thank you for your understanding. TS/CE and TS/FM Groups Tel.7 4188 or 16 4314
Goddard Robotic Telescope (GRT)
National Aeronautics and Space Administration — Since it is not possible to predict when a Gamma-Ray Burst (GRB) occurs, the follow-up ground telescopes must be distributed as uniform as possible all over the...
Tyson, J A; Angel, J R P; Wittman, David
2001-01-01
Weak gravitational lensing enables direct reconstruction of dark matter maps over cosmologically significant volumes. This research is currently telescope-limited. The Dark Matter Telescope (DMT) is a proposed 8.4 m telescope with a 3 degree field of view, with an etendue of 260 $(m. degree)^2$, ten times greater than any other current or planned telescope. With its large etendue and dedicated observational mode, the DMT fills a nearly unexplored region of parameter space and enables projects that would take decades on current facilities. The DMT will be able to reach 10-sigma limiting magnitudes of 27-28 magnitude in the wavelength range .3 - 1 um over a 7 square degree field in 3 nights of dark time. Here we review its unique weak lensing cosmology capabilities and the design that enables those capabilities.
Djupvik, Anlaug Amanda; Andersen, Johannes
2009-01-01
An overview of the Nordic Optical Telescope (NOT) is presented. Emphasis is on current capabilities of direct interest to the scientific user community, including instruments. Educational services and prospects and strategies for the future are discussed briefly as well.
The characteristics and capabilities of the Hubble Space Telescope (HST) are described. The telescope can provide an angular resolution of about 0.1 arcsec, a faint stellar limiting magnitude of about 28 mag, and UV observations greater than or equal to 1150 A. The scientific instruments on the HST include: a wide-field and planetary camera, a faint object spectrograph, a faint object camera, a high speed photometer, a high resolution spectrograph, and three fine guidance sensors. The role of the Space Telescope Science Institute in managing and distributing the HST data is examined. The application of the telescope to the study of cosmology, evolution, QSOs and AGNs, galaxies and cluster, stars and the interstellar medium, and planetary astronomy is proposed
Optimized Schwarz Methods for Maxwell's equations with non-zero electric conductivity
Dolean, Victoria; El Bouajaji, Mohamed; Gander, Martin Jakob; Lanteri, Stéphane
2010-01-01
The first ideas for optimized Schwarz methods for Maxwell's equations came from the analysis of optimized Schwarz methods for the Helmholtz equation, see [3, 4, 2, 11]. For the case of the rot-rot formulation of the Maxwell equations, optimized Schwarz methods were developed in [1]. The systematic study of Schwarz methods for Maxwell's equations in their general formulation was started in [9, 10], and an entire hierarchy of families of optimized Schwarz methods was analyzed in [8], see also [...
Bigongiari, Ciro
2016-01-01
The Cherenkov Telescope Array (CTA) is planned to be the next generation ground based observatory for very high energy (VHE) gamma-ray astronomy. Gamma-rays provide a powerful insight into the non-thermal universe and hopefully a unique probe for new physics. Imaging Cherenkov telescopes have already discovered more than 170 VHE gamma-ray emitters providing plentiful of valuable data and clearly demonstrating the power of this technique. In spite of the impressive results there are indication...
The Atacama Cosmology Telescope
Kosowsky, Arthur
2004-01-01
The Atacama Cosmology Telescope (ACT) project is described. This multi-institution collaboration aims to produce arcminute-resolution and micro-Kelvin sensitivity maps of the microwave background temperature over 200 square degrees of the sky in three frequency bands. We give a brief overview of the scientific motivations for such a map, followed by a design outline of our six-meter custom telescope, an overview of our proposed bolometer array detector technology, and site considerations and ...
Hubble Space Telescope Configuration
1985-01-01
This image illustrates the overall Hubble Space Telescope (HST) configuration. The HST is the product of a partnership between NASA, European Space Agency Contractors, and the international community of astronomers. It is named after Edwin P. Hubble, an American Astronomer who discovered the expanding nature of the universe and was the first to realize the true nature of galaxies. The purpose of the HST, the most complex and sensitive optical telescope ever made, is to study the cosmos from a low-Earth orbit. By placing the telescope in space, astronomers are able to collect data that is free of the Earth's atmosphere. The HST detects objects 25 times fainter than the dimmest objects seen from Earth and provides astronomers with an observable universe 250 times larger than visible from ground-based telescopes, perhaps as far away as 14 billion light-years. The HST views galaxies, stars, planets, comets, possibly other solar systems, and even unusual phenomena such as quasars, with 10 times the clarity of ground-based telescopes. The major elements of the HST are the Optical Telescope Assembly (OTA), the Support System Module (SSM), and the Scientific Instruments (SI). The HST is approximately the size of a railroad car, with two cylinders joined together and wrapped in a silvery reflective heat shield blanket. Wing-like solar arrays extend horizontally from each side of these cylinders, and dish-shaped anternas extend above and below the body of the telescope. The HST was deployed from the Space Shuttle Discovery (STS-31 mission) into Earth orbit in April 1990. The Marshall Space Flight Center had responsibility for design, development, and construction of the HST. The Perkin-Elmer Corporation, in Danbury, Connecticut, developed the optical system and guidance sensors. The Lockheed Missile and Space Company of Sunnyvale, California produced the protective outer shroud and spacecraft systems, and assembled and tested the finished telescope.
Alignment telescope for Antares
The Antares Automatic Alignment System employs a specially designed telescope for alignment of its laser beamlines. There are two telescopes in the system, and since each telescope is a primary alignment reference, stringent boresight accuracy and stability over the focus range were required. Optical and mechanical designs, which meet this requirement as well as that of image quality over a wide wavelength band, are described. Special test techniques for initial assembly and alignment of the telescope are also presented. The telescope, which has a 180-mm aperture FK51-KZF2 type glass doublet objective, requires a boresight accuracy of 2.8 μrad at two focal lengths, and object distances between 11 meters and infinity. Travel of a smaller secondary doublet provides focus from 11 m to infinity with approximately 7.8 m effective focal length. By flipping in a third doublet, the effective focal length is reduced to 2.5 m. Telescope alignment was accomplished by using a rotary air bearing to establish an axis in front of the system and placing the focus of a Laser Unequal Path Interferometer (LUPI) at the image plane
Einstein-Maxwell-Anti-de-Sitter spinning solitons
Herdeiro, Carlos; Radu, Eugen
2016-06-01
Electrostatics on global Anti-de-Sitter (AdS) spacetime is sharply different from that on global Minkowski spacetime. It admits a multipolar expansion with everywhere regular, finite energy solutions, for every multipole moment except the monopole [1]. A similar statement holds for global AdS magnetostatics. We show that everywhere regular, finite energy, electric plus magnetic fields exist on AdS in three distinct classes: (I) with non-vanishing total angular momentum J; (II) with vanishing J but non-zero angular momentum density, Tφt ; (III) with vanishing J and Tφt . Considering backreaction, these configurations remain everywhere smooth and finite energy, and we find, for example, Einstein-Maxwell-AdS solitons that are globally - Type I - or locally (but not globally) - Type II - spinning. This backreaction is considered first perturbatively, using analytical methods and then non-perturbatively, by constructing numerical solutions of the fully non-linear Einstein-Maxwell-AdS system. The variation of the energy and total angular momentum with the boundary data is explicitly exhibited for one example of a spinning soliton.
Reduced basis method for Maxwell's equations with resonance phenomena
Hammerschmidt, Martin; Herrmann, Sven; Pomplun, Jan; Zschiedrich, Lin; Burger, Sven; Schmidt, Frank
2015-09-01
Rigorous optical simulations of 3-dimensional nano-photonic structures are an important tool in the analysis and optimization of scattering properties of nano-photonic devices or parameter reconstruction. To construct geometrically accurate models of complex structured nano-photonic devices the finite element method (FEM) is ideally suited due to its flexibility in the geometrical modeling and superior convergence properties. Reduced order models such as the reduced basis method (RBM) allow to construct self-adaptive, error-controlled, very low dimensional approximations for input-output relationships which can be evaluated orders of magnitude faster than the full model. This is advantageous in applications requiring the solution of Maxwell's equations for multiple parameters or a single parameter but in real time. We present a reduced basis method for 3D Maxwell's equations based on the finite element method which allows variations of geometric as well as material and frequency parameters. We demonstrate accuracy and efficiency of the method for a light scattering problem exhibiting a resonance in the electric field.
Einstein-aether theory with a Maxwell field: General formalism
Balakin, Alexander B., E-mail: Alexander.Balakin@kpfu.ru [Department of General Relativity and Gravitation, Institute of Physics, Kazan Federal University, Kremlevskaya str. 18, Kazan 420008 (Russian Federation); Lemos, José P.S., E-mail: joselemos@ist.utl.pt [Centro Multidisciplinar de Astrofísica-CENTRA, Departamento de Física, Instituto Superior Técnico-IST, Universidade de Lisboa-UL, Avenida Rovisco Pais 1, 1049-001 Lisboa (Portugal)
2014-11-15
We extend the Einstein-aether theory to include the Maxwell field in a nontrivial manner by taking into account its interaction with the time-like unit vector field characterizing the aether. We also include a generic matter term. We present a model with a Lagrangian that includes cross-terms linear and quadratic in the Maxwell tensor, linear and quadratic in the covariant derivative of the aether velocity four-vector, linear in its second covariant derivative and in the Riemann tensor. We decompose these terms with respect to the irreducible parts of the covariant derivative of the aether velocity, namely, the acceleration four-vector, the shear and vorticity tensors, and the expansion scalar. Furthermore, we discuss the influence of an aether non-uniform motion on the polarization and magnetization of the matter in such an aether environment, as well as on its dielectric and magnetic properties. The total self-consistent system of equations for the electromagnetic and the gravitational fields, and the dynamic equations for the unit vector aether field are obtained. Possible applications of this system are discussed. Based on the principles of effective field theories, we display in an appendix all the terms up to fourth order in derivative operators that can be considered in a Lagrangian that includes the metric, the electromagnetic and the aether fields.
Einstein-Maxwell dynamics as a P(4) affine theory
In Newtonian mechanics the energy of a particle is defined only up to an arbitrary additive constant. By using affine functions to model the Newtonian energy we show that it is possible to reformulate arbitrary time- and velocity-independent forces as R1 affine gauge potentials. Solutions of Newton's second law then define R1 affine energy geodesics, and the R1 flat gauge potentials are shown to correspond to conservative Newtonian forces. We generalize these ideas to relativistic mechanics by modeling the energy-momentum of classical particles as R4 affine four-vectors. If this R4 affine structure is to be compatible with the O(1,3) Riemannian structure of spacetime, then the R4 gauge potential must correspond to an antisymmetric tensor field on spacetime, and this field is identified with the electromagnetic field tensor. We are eventually led to a reformulation of the Einstein-Maxwell theory as a P(4) = O(1,3) x R4 affine gauge theory in which the timelike affine geodesics correspond to Lorentz-force-law trajectories, and the Einstein-Maxwell field equations are reformulated as gauge field equations in terms of the P(4) curvature
Ruhl, J.E.; Ade, P.A.R.; Carlstrom, J.E.; Cho, H.M.; Crawford,T.; Dobbs, M.; Greer, C.H.; Halverson, N.W.; Holzapfel, W.L.; Lanting,T.M.; Lee, A.T.; Leitch, E.M.; Leong, J.; Lu, W.; Lueker, M.; Mehl, J.; Meyer, S.S.; Mohr, J.J.; Padin, S.; Plagge, T.; Pryke, C.; Runyan, M.C.; Schwan, D.; Sharp, M.K.; Spieler, H.; Staniszewski, Z.; Stark, A.A.
2004-11-04
A new 10 meter diameter telescope is being constructed for deployment at the NSF South Pole research station. The telescope is designed for conducting large-area millimeter and sub-millimeter wave surveys of faint, low contrast emission, as required to map primary and secondary anisotropies in the cosmic microwave background. To achieve the required sensitivity and resolution, the telescope design employs an off-axis primary with a 10 m diameter clear aperture. The full aperture and the associated optics will have a combined surface accuracy of better than 20 microns rms to allow precision operation in the submillimeter atmospheric windows. The telescope will be surrounded with a large reflecting ground screen to reduce sensitivity to thermal emission from the ground and local interference. The optics of the telescope will support a square degree field of view at 2mm wavelength and will feed a new 1000-element micro-lithographed planar bolometric array with superconducting transition-edge sensors and frequency-multiplexed readouts. The first key project will be to conduct a survey over 4000 degrees for galaxy clusters using the Sunyaev-Zeldovich Effect. This survey should find many thousands of clusters with a mass selection criteria that is remarkably uniform with redshift. Armed with redshifts obtained from optical and infrared follow-up observations, it is expected that the survey will enable significant constraints to be placed on the equation of state of the dark energy.
Towers for Antarctic Telescopes
Hammerschlag, R. H.; Bettonvil, F. C. M.; Jägers, A. P. L.; Nielsen, G.
To take advantage of the exceptional seeing above the boundary layer on Antarctic sites, a high-resolution telescope must be mounted on a support tower. An open transparent tower of framework minimizes the upward temperature-disturbed airflow. A typical minimum height is 30m. The tower platform has to be extremely stable against wind-induced rotational motions, which have to be less than fractions of an arc second, unusually small from a mechanical engineering viewpoint. In a traditional structure, structural deflections result in angular deflections of the telescope platform, which introduce tip and tilt motions in the telescope. However, a structure that is designed to deflect with parallel motion relative to the horizontal plane will undergo solely translation deflections in the telescope platform and thus will not degrade the image. The use of a parallel motion structure has been effectively demonstrated in the design of the 15-m tower for the Dutch Open Telescope (DOT) on La Palma. Special framework geometries are developed, which make it possible to construct high towers in stories having platforms with extreme stability against wind-induced tilt. These geometric solutions lead to constructions, being no more massive than a normal steel framework carrying the same load. Consequently, these lightweight towers are well suited to difficult sites as on Antarctica. A geometry with 4 stories has been worked out.
Murabona Oduori, Susan
2015-08-01
The telescope has been around for more than 400 years, and through good use of it scientists have made many astonishing discoveries and begun to understand our place in the universe. Most people, however, have never looked through one. Yet it is a great tool for cool science and observation especially in a continent and country with beautifully dark skies. The Travelling Telescope project aims to invite people outside under the stars to learn about those curious lights in the sky.The Travelling Telescope aims to promote science learning to a wide range of Kenyan schools in various locations exchanging knowledge about the sky through direct observations of celestial bodies using state of the art telescopes. In addition to direct observing we also teach science using various hands-on activities and astronomy software, ideal for explaining concepts which are hard to understand, and for a better grasp of the sights visible through the telescope. We are dedicated to promoting science using astronomy especially in schools, targeting children from as young as 3 years to the youth, teachers, their parents and members of the public. Our presentation focuses on the OAD funded project in rural coastal Kenya.
Woźniak, Przemysław
Robotic telescopes are revolutionizing the way astronomers collect their dataand conduct sky surveys. This chapter begins with a discussion of principles thatguide the process of designing, constructing, and operating telescopes andobservatories that offer a varying degree of automation, from instruments remotelycontrolled by observers to fully autonomous systems requiring no humansupervision during their normal operations. Emphasis is placed on designtrade-offs involved in building end-to-end systems intended for a wide range ofscience applications. The second part of the chapter contains descriptions ofseveral projects and instruments, both existing and currently under development.It is an attempt to provide a representative selection of actual systems thatillustrates state of the art in technology, as well as important ideas and milestonesin the development of the field. The list of presented instruments spans the fullrange in size starting from small all-sky monitors, through midrange robotic andsurvey telescopes, and finishing with large robotic instruments and surveys.Explosive growth of telescope networking is enabling entirely new modesof interaction between the survey and follow-up observing. Increasingimportance of standardized communication protocols and software is stressed.These developments are driven by the fusion of robotic telescope hardware,massive storage and databases, real-time knowledge extraction, and datacross-correlation on a global scale. The chapter concludes with examplesof major science results enabled by these new technologies and futureprospects.
Kitchin, C R
2013-01-01
Telescopes and Techniques has proved itself in its first two editions, having become probably one of the most widely used astronomy texts, both for amateur astronomers and astronomy and astrophysics undergraduates. Both earlier editions of the book were widely used for introductory practical astronomy courses in many universities. In this Third Edition the author guides the reader through the mathematics, physics and practical techniques needed to use today's telescopes (from the smaller models to the larger instruments installed in many colleges) and how to find objects in the sky. Most of the physics and engineering involved is described fully and requires little prior knowledge or experience. Both visual and electronic imaging techniques are covered, together with an introduction to how data (measurements) should be processed and analyzed. A simple introduction to radio telescopes is also included. Brief coverage of the more advanced topics of photometry and spectroscopy are included, but mainly to enable ...
Integrated Modeling of Telescopes
Andersen, Torben
2011-01-01
With increasingly complex and costly opto-mechanical systems, there is a growing need for reliable computer modeling and simulation. The field of integrated modeling, combining optics, mechanics, control engineering, and other disciplines, is the subject of this book. Although the book primarily focuses on ground-based optical telescopes, the techniques introduced are applicable also to other wavelengths and to other opto-mechanical applications on the ground or in space. Basic tools of integrated modeling are introduced together with concepts of ground-based telescopes. Modeling of optical systems, structures, wavefront control systems with emphasis on segmented mirror control, and active and adaptive optics are described together with a variety of noise sources; many examples are included in this book. Integrated Modeling of Telescopes is a text for physicists and engineers working in the field of opto-mechanical design and wavefront control, but it will also be valuable as a textbook for PhD students.
D'Amico, Nichi
2011-08-01
We present the status of the Sardinia Radio Telescope (SRT) project, a new general purpose, fully steerable 64 m diameter parabolic radio telescope under construction in Sardinia. The instrument is funded by Italian Ministry of University and Research (MIUR), by the Sardinia Regional Government (RAS), and by the Italian Space Agency (ASI), and it is charge to three research structures of the National Institute for Astrophysics (INAF): the Institute of Radio Astronomy of Bologna, the Cagliari Astronomical Observatory (in Sardinia), and the Arcetri Astrophysical Observatory in Florence. The radio telescope has a shaped Gregorian optical configuration with a 8 m diameter secondary mirror and additional Beam-Wave Guide (BWG) mirrors. One of the most challenging feature of SRT is the active surface of the primary reflector which provides good efficiency up to about 100 GHz. This paper reports on the most recent advances of the construction.
Configurable Aperture Space Telescope
Ennico, Kimberly; Bendek, Eduardo
2015-01-01
In December 2014, we were awarded Center Innovation Fund to evaluate an optical and mechanical concept for a novel implementation of a segmented telescope based on modular, interconnected small sats (satlets). The concept is called CAST, a Configurable Aperture Space Telescope. With a current TRL is 2 we will aim to reach TLR 3 in Sept 2015 by demonstrating a 2x2 mirror system to validate our optical model and error budget, provide straw man mechanical architecture and structural damping analyses, and derive future satlet-based observatory performance requirements. CAST provides an alternative access to visible and/or UV wavelength space telescope with 1-meter or larger aperture for NASA SMD Astrophysics and Planetary Science community after the retirement of HST
Infinite Maxwell fish-eye lens as a complement for an imaging device
Liu, Yangjie; Naeem, Majid; Hao, Yang
2015-01-01
This manuscript proposes a new imaging medium via isotropic refractive index of heterogeneous medium. By aid of conformal map, one transfers the full Maxwell fisheye into a mapped profile within a unit circle. Thus the imaging resolution of this new profile is maintained as good as the truncated Maxwell fisheye profile or its conformally-mapped counterpart in previous literature.
The Goldberg-Sachs theorem and the alignment condition for Einstein-Maxwell fields
Bergh, Norbert Van den
2016-01-01
A new characterisation is given of the Garcia-Plebanski and Plebanski-Hacyan metrics within the family of non-null aligned Einstein-Maxwell fields with a cosmological constant and of the Debever-Kamran-McLenaghan `class D' metrics with non-vanishing cosmological constant within the general family of non-null Einstein-Maxwell fields.
Comment on the "Maxwell Equations as the One-Photon Quantum Equation" by A. Gersten
Dvoeglazov, V V
2000-01-01
We show that the Gersten derivation of Maxwell equations can be generalized. It actually leads to additional solutions of `S=1 equations'. They follow directly from previous considerations by Majorana, Oppenheimer, Weinberg and Ogievetskii and Polubarinov. Therefore, {\\it generalized} Maxwell equations should be used as a guideline for proper interpretations of quantum theories.
Peristaltic flow of a Maxwell fluid in a channel with compliant walls
Ali, Nasir [Department of Mathematics, Quaid-i-Azam University 45320, Islamabad 44000 (Pakistan)], E-mail: nasirali_qau@yahoo.com; Hayat, Tasawar [Department of Mathematics, Quaid-i-Azam University 45320, Islamabad 44000 (Pakistan); Asghar, Saleem [Department of Mathematical Sciences, COMSATS Institute of Information Technology, Islamabad (Pakistan)
2009-01-15
This paper describes the peristaltic motion of a non-Newtonian fluid in a channel having compliant boundaries. Constitutive equations for a Maxwell fluid have been used. Perturbation method has been used for the analytic solution. The influence of pertinent parameters is analyzed. Comparison of the present analysis of Maxwell fluid is made with the existing results of viscous fluid.
2011-09-13
... National Park Service Notice of Inventory Completion: Maxwell Museum of Anthropology, University of New... Museum of Anthropology, University of New Mexico has completed an inventory of human remains, in... itself to be culturally affiliated with the human remains may contact the Maxwell Museum of...
2012-08-02
... National Park Service Notice of Inventory Completion: Maxwell Museum of Anthropology, University of New... Museum of Anthropology has completed an inventory of human remains in consultation with the appropriate... Maxwell Museum of Anthropology at the address below by September 4, 2012. ADDRESSES: Heather...
The Covariant Formulation of Maxwell's Equations Expressed in a Form Independent of Specific Units
Heras, Jose A.; Baez, G.
2009-01-01
The covariant formulation of Maxwell's equations can be expressed in a form independent of the usual systems of units by introducing the constants alpha, beta and gamma into these equations. Maxwell's equations involving these constants are then specialized to the most commonly used systems of units: Gaussian, SI and Heaviside-Lorentz by giving…
2011-01-01
With its pure aperture up to 985mm, the New Vacuum Solar Telescope of China （NVST） has become the world＇s biggest vacuum solar telescope. The main science task of NVST is the high-resolution observation of photosphere and chromosphere including their fine structure of magnetic field on the sun. The NVST was equipped with many new technologies and powerful instruments, such as an adaptive optical system, a polarization analyzer, two vertical spectrographs, a high-resolution image system and a very narrow Ha filter （0.125A）.
Athermal laser launch telescopes
Kamphues, F.G.; Henselmans, R.; Rijnveld, N.; Lemmen, M.H.J.; Doelman, N.J.; Nijkerk, M.D.
2011-01-01
ESO has developed a concept for a compact laser guide star unit for use in future Adaptive Optics (AO) systems. A small powerful laser is combined with a telescope that launches the beam, creating a single modular unit that can be mounted directly on a large telescope. This approach solves several of the stability problems experienced with a number of first generation laser guide star systems around the world. Four of these compact laser guide stars will be used for the new VLT 4LGSF Adaptive...
Up to now the 20-300 GeV energy range has been inaccessible to gamma-ray astronomy. Here we report on a design for a 17-m φ air Cerenkov telescope, dubbed MAGIC telescope, which will have a threshold of 20 GeV, a large collection area of > 105 m2 and a high gamma/hadron separation power. It is estimated that the hardware investments would be about 3.5 M$ and 2.5-3.5 years would be needed for the construction. (author)
Convection displacement current and alternative form of Maxwell-Lorentz equations
Chubykalo, A E; Chubykalo, Andrew E.; Smirnov-Rueda, Roman
1996-01-01
Some mathematical inconsistencies in the conventional form of Maxwell's equations extended by Lorentz for a single charge system are discussed. To surmount these in framework of Maxwellian theory, a novel convection displacement current is considered as additional and complementary to the famous Maxwell displacement current. It is shown that this form of the Maxwell-Lorentz equations is similar to that proposed by Hertz for electrodynamics of bodies in motion. Original Maxwell's equations can be considered as a valid approximation for a continuous and closed (or going to infinity) conduction current. It is also proved that our novel form of the Maxwell-Lorentz equations is relativistically invariant. In particular, a relativistically invariant gauge for quasistatic fields has been found to replace the non-invariant Coulomb gauge. The new gauge condition contains the famous relationship between electric and magnetic potentials for one uniformly moving charge that is usually a! ttributed to the Lorentz transfor...
On the locally rotationally symmetric Einstein-Maxwell perfect fluid
Pugliese, D.; Valiente Kroon, J. A.
2016-06-01
We examine the stability of Einstein-Maxwell perfect fluid configurations with a privileged radial direction by means of a 1+1+2-tetrad formalism. We use this formalism to cast in a quasilinear symmetric hyperbolic form the equations describing the evolution of the system. This hyperbolic reduction is used to discuss the stability of linear perturbations in some special cases. By restricting the analysis to isotropic fluid configurations, we assume a constant electrical conductivity coefficient for the fluid. As a result of this analysis we provide a complete classification and characterization of various stable and unstable configurations. We find, in particular, that in many cases the stability conditions are strongly determined by the constitutive equations and the electric conductivity. A threshold for the emergence of the instability appears in both contracting and expanding systems.
Holographic Renormalization of Einstein-Maxwell-Dilaton Theories
Kim, Bom Soo
2016-01-01
We generalize the boundary value problem with a mixed boundary condition that involves the gauge and scalar fields in the context of Einstein-Maxwell-Dilaton theories. In particular, the expectation value of the dual scalar operator can be a function of the expectation value of the current operator. The properties are prevalent in a fixed charge ensemble because the conserved charge is shared by both fields through the dilaton coupling, which is also responsible for non-Fermi liquid properties. We study the on-shell action and the stress energy tensor to note practical importances of the boundary value problem. In the presence of the scalar fields, physical quantities are not fully fixed due to the finite boundary terms that manifest in the massless scalar or the scalar with mass saturating the Breitenlohner-Freedman bound.