Some Surprises in Relativistic Gravity
Santos, N O
2016-01-01
General Relativity has had tremendous success both on the theoretical and the experimental fronts for over a century now. However, the contents of the theory are far from exhausted. Only very recently, with the detection of gravitational waves from colliding black holes, we have started probing the behavior of gravity in the strongly non-linear regime. Even today, the studies of black holes keep revealing more and more paradoxes and bizarre results. In this paper, inspired by David Hilbert's startling observation, we show that, contrary to the conventional wisdom, a freely falling test particle feels gravitational repulsion by a black hole as seen by the asymptotic observer. We dig deeper into this surprising behavior of relativistic gravity and offer some explanations.
Relativistic Cyclotron Instability in Anisotropic Plasmas
López, Rodrigo A.; Moya, Pablo S.; Navarro, Roberto E.; Araneda, Jaime A.; Muñoz, Víctor; Viñas, Adolfo F.; Alejandro Valdivia, J.
2016-11-01
A sufficiently large temperature anisotropy can sometimes drive various types of electromagnetic plasma micro-instabilities, which can play an important role in the dynamics of relativistic pair plasmas in space, astrophysics, and laboratory environments. Here, we provide a detailed description of the cyclotron instability of parallel propagating electromagnetic waves in relativistic pair plasmas on the basis of a relativistic anisotropic distribution function. Using plasma kinetic theory and particle-in-cell simulations, we study the influence of the relativistic temperature and the temperature anisotropy on the collective and noncollective modes of these plasmas. Growth rates and dispersion curves from the linear theory show a good agreement with simulations results.
Single electron detection and spectroscopy via relativistic cyclotron radiation
Asner, D M; de Viveiros, L; Doe, P J; Fernandes, J L; Fertl, M; Finn, E C; Formaggio, J A; Furse, D; Jones, A M; Kofron, J N; LaRoque, B H; Leber, M; McBride, E L; Miller, M L; Mohanmurthy, P; Monreal, B; Oblath, N S; Robertson, R G H; Rosenberg, L J; Rybka, G; Rysewyk, D; Sternberg, M G; Tedeschi, J R; Thummler, T; VanDevender, B A; Woods, N L
2014-01-01
It has been understood since 1897 that accelerating charges must emit electromagnetic radiation. Cyclotron radiation, the particular form of radiation emitted by an electron orbiting in a magnetic field, was first derived in 1904. Despite the simplicity of this concept, and the enormous utility of electron spectroscopy in nuclear and particle physics, single-electron cyclotron radiation has never been observed directly. Here we demonstrate single-electron detection in a novel radiofrequency spec- trometer. We observe the cyclotron radiation emitted by individual magnetically-trapped electrons that are produced with mildly-relativistic energies by a gaseous radioactive source. The relativistic shift in the cyclotron frequency permits a precise electron energy measurement. Precise beta elec- tron spectroscopy from gaseous radiation sources is a key technique in modern efforts to measure the neutrino mass via the tritium decay endpoint, and this work demonstrates a fundamentally new approach to precision beta sp...
Single-electron detection and spectroscopy via relativistic cyclotron radiation
Energy Technology Data Exchange (ETDEWEB)
Asner, David M.; Bradley, Rich; De Viveiros Souza Filho, Luiz A.; Doe, Peter J.; Fernandes, Justin L.; Fertl, M.; Finn, Erin C.; Formaggio, Joseph; Furse, Daniel L.; Jones, Anthony M.; Kofron, Jared N.; LaRoque, Benjamin; Leber, Michelle; MCBride, Lisa; Miller, M. L.; Mohanmurthy, Prajwal T.; Monreal, Ben; Oblath, Noah S.; Robertson, R. G. H.; Rosenberg, Leslie; Rybka, Gray; Rysewyk, Devyn M.; Sternberg, Michael G.; Tedeschi, Jonathan R.; Thummler, Thomas; VanDevender, Brent A.; Woods, N. L.
2015-04-01
It has been understood since 1897 that accelerating charges should emit electromagnetic radiation. Cyclotron radiation, the particular form of radiation emitted by an electron orbiting in a magnetic field, was first derived in 1904. Despite the simplicity of this concept, and the enormous utility of electron spectroscopy in nuclear and particle physics, single-electron cyclotron radiation has never been observed directly. Here we demonstrate single-electron detection in a novel radiofrequency spectrometer. We observe the cyclotron radiation emitted by individual electrons that are produced with mildly-relativistic energies by a gaseous radioactive source and are magnetically trapped. The relativistic shift in the cyclotron frequency permits a precise electron energy measurement. Precise beta electron spectroscopy from gaseous radiation sources is a key technique in modern efforts to measure the neutrino mass via the tritium decay endpoint, and this work is a proof-of-concept for future neutrino mass experiments using this technique.
A relativistic model of electron cyclotron current drive efficiency in tokamak plasmas
Lin-Liu Y.R.; Hu Y.J.; Hu Y.M.
2012-01-01
A fully relativistic model of electron cyclotron current drive (ECCD) efficiency based on the adjoint function techniques is considered. Numerical calculations of the current drive efficiency in a tokamak by using the variational approach are performed. A fully relativistic extension of the variational principle with the modified basis functions for the Spitzer function with momentum conservation in the electron-electron collision is described in general tokamak geometry. The model developed ...
Institute of Scientific and Technical Information of China (English)
SU Zhen-Peng; ZHENG Hui-Nan
2009-01-01
The bounce-averaged Fokker-Planck equation is solved to study the relativistic electron phase space density(PSD)evolution in the outer radiation belt due to resonant interactions with plasmaspheric plume electromagnetic ion cyclotron(EMIC)waves.It is found that the PSDs of relativistic electrons can be depleted by 1-3 orders of magnitude in 5h,supporting the previous finding that resonant interactions with EMIC waves may account for the frequently observed relativistic electron flux dropouts in the outer radiation belt during the main phase of a storm.The significant precipitation Joss of ～Me V electrons is primarily induced by the EMIC waves in H~+ and He~+ bands.The rapid remove of highly relativistic electrons(＞5 MeV)is mainly driven by the EMIC waves in O~+ band at lower pitch-angles,as well as the EMIC waves in H~+ and He~+ bands at larger pitch-angles.Moreover,a stronger depletion of relativistic electrons is found to occur over a wider pitch angle range when EMIC waves are centering relatively higher in the band.
``Pheudo-cyclotron'' radiation of non-relativistic particles in small-scale magnetic turbulence
Keenan, Brett; Ford, Alex; Medvedev, Mikhail V.
2014-03-01
Plasma turbulence in some astrophysical objects (e.g., weakly magnetized collisionless shocks in GRBs and SN) has small-scale magnetic field fluctuations. We study spectral characteristics of radiation produced by particles moving in such turbulence. It was shown earlier that relativistic particles produce jitter radiation, which spectral characteristics are markedly different from synchrotron radiation. Here we study radiation produced by non-relativistic particles. In the case of a homogeneous fields, such radiation is cyclotron and its spectrum consists of just a single harmonic at the cyclotron frequency. However, in the sub-Larmor-scale turbulence, the radiation spectrum is much reacher and reflects statistical properties of the underlying magnetic field. We present both analytical estimates and results of ab initio numerical simulations. We also show that particle propagation in such turbulence is diffusive and evaluate the diffusion coefficient. We demonstrate that the diffusion coefficient correlates with some spectral parameters. These results can be very valuable for remote diagnostics of laboratory and astrophysical plasmas. Supported by grant DOE grant DE-FG02-07ER54940 and NSF grant AST-1209665.
Uzbekov, Bogdan; Shprits, Yuri Y.; Orlova, Ksenia
2016-10-01
Electromagnetic Ion Cyclotron (EMIC) waves are transverse plasma waves that are generated in the Earth magnetosphere by ring current protons with temperature anisotropy in three different bands: below the H+, He+ and O+ ion gyrofrequencies. EMIC events are enhanced during the main phase of a geomagnetic storm when intensifications in the electric field result in enhanced injections of ions and are usually confined to high-density regions just inside the plasmapause or within drainage plumes. EMIC waves are capable of scattering radiation belt electrons and thus provide an important link between the intensification of the electric field, ion populations, and radiation belt electrons. Bounce-averaged diffusion coefficients computed with the assumption of parallel wave propagation are compared to the results of the code that uses the full cold plasma dispersion relation taking into account oblique propagation of waves and higher-order resonances. We study the sensitivity of the scattering rates to a number of included higher-order resonances, wave spectral distribution parameters, wave normal angle distribution parameters, ambient plasma density, and ion composition. Inaccuracies associated with the neglect of higher-order resonances and oblique propagation of waves are compared to potential errors introduced by uncertainties in the model input parameters.
Institute of Scientific and Technical Information of China (English)
Liu Yong; Han Xiang; Ti Ang; Wang Yu-Min; Ling Bi-Li; Hu Li-Qun; Gao Xiang
2012-01-01
This paper presents a theoretical calculation of the effects of relativistic broadening and frequency down-shift on the electron cyclotron emission measurements for a wide range of plasma parameters in the Experimental Advanced Superconducting Tokamak (EAST).The calculation is based on the radiation transfer equation,with the reabsorption and reemission processes taken into account.The broadening effect contributes to the radial resolution of the measurement,and the calculation results indicate that it is ～ 2 cm in the case of the central electron temperature 10 keV.A pseudo radial displacement of the obtained electron temperature profile occurs if the relativistic frequency down-shift effect is not taken into account in the determination of the emission layer position.The shift could be a few centimeters as the electron temperature increases,and this effect should be taken into account.
Electron Cloud Cyclotron Resonances in the Presence of a Short-bunch-length Relativistic Beam
Energy Technology Data Exchange (ETDEWEB)
Celata, C.M.; Furman, Miguel A.; Vay, J.-L.; Yu, Jennifer W.
2008-09-02
Computer simulations using the 2D code"POSINST" were used to study the formation of the electron cloud in the wiggler section of the positron damping ring of the International Linear Collider. In order to simulate an x-y slice of the wiggler (i.e., a slice perpendicular to the beam velocity), each simulation assumed a constant vertical magnetic field. At values of the magnetic field where the cyclotron frequency was an integral multiple of the bunch frequency, and where the field strength was less than approximately 0.6 T, equilibrium average electron densities were up to three times the density found at other neighboring field values. Effects of this resonance between the bunch and cyclotron frequency are expected to be non-negligible when the beam bunch length is much less than the product of the electron cyclotron period and the beam velocity, for a beam moving at v~;;c. Details of the dynamics of the resonance are described.
Eliasson, B.; Papadopoulos, K.
2017-10-01
A theoretical study of the propagation of left-hand polarized shear Alfvén waves in spatially decreasing magnetic field geometries near the EMIC resonance, including the spectrum and amplitude of the mode converted EMIC waves and the pitch angle scattering of relativistic electrons transiting the resonant region, is presented. The objective of the paper is to motivate an experimental study of the subject using the UCLA LAPD chamber. The results are relevant in exploring the possibility that shear Alfvén waves strategically injected into the radiation belts using either ionospheric heating from ground based RF transmitters or injected by transmitters based on space platforms can enhance the precipitation rate of trapped relativistic electrons. Effects of multi-ionic composition are also investigated.
Gamayunov, K. V.; Khazanov, G. V.
2007-01-01
We consider the effect of oblique EMIC waves on relativistic electron scattering in the outer radiation belt using simultaneous observations of plasma and wave parameters from CRRES. The main findings can be s ummarized as follows: 1. In 1comparison with field-aligned waves, int ermediate and highly oblique distributions decrease the range of pitc h-angles subject to diffusion, and reduce the local scattering rate b y an order of magnitude at pitch-angles where the principle absolute value of n = 1 resonances operate. Oblique waves allow the absolute va lue of n > 1 resonances to operate, extending the range of local pitc h-angle diffusion down to the loss cone, and increasing the diffusion at lower pitch angles by orders of magnitude; 2. The local diffusion coefficients derived from CRRES data are qualitatively similar to the local results obtained for prescribed plasma/wave parameters. Conseq uently, it is likely that the bounce-averaged diffusion coefficients, if estimated from concurrent data, will exhibit the dependencies similar to those we found for model calculations; 3. In comparison with f ield-aligned waves, intermediate and highly oblique waves decrease th e bounce-averaged scattering rate near the edge of the equatorial lo ss cone by orders of magnitude if the electron energy does not excee d a threshold (approximately equal to 2 - 5 MeV) depending on specified plasma and/or wave parameters; 4. For greater electron energies_ ob lique waves operating the absolute value of n > 1 resonances are more effective and provide the same bounce_averaged diffusion rate near the loss cone as fiel_aligned waves do.
Energy Technology Data Exchange (ETDEWEB)
Sato, Masayasu; Isei, Nobuaki; Ishida, Sinichi [Japan Atomic Energy Research Inst., Naka, Ibaraki (Japan). Naka Fusion Research Establishment
1995-11-01
Effect of relativistic frequency down-shift on the determination of the electron temperature profile from electron cyclotron emission(ECE) in JT-60U tokamak plasmas is studied. The radial shift of the electron temperature profile due to the effects is not negligible, compared with the spatial resolution of ECE measurement systems of JT-60U. Therefore it is necessary to correct the effect for precise measurement of the electron temperature profile. Dependencies of the shifted frequency on the electron density, electron temperature and toroidal magnetic field are studied for the uniform electron density and parabolic electron temperature profile in JT-60U. It is revealed to be necessary for the estimation of shift due to the relativistic down-shift frequency to take into account of the optical thickness. (author).
Cyclotron lines in X-ray pulsars as a probe of relativistic plasmas in superstrong magnetic fields
Dal Fiume, D; Masetti, N; Orlandini, M; Palazzi, E; Del Sordo, S; Santangelo, A; Segreto, A; Oosterbroek, T; Parmar, A N; Frontera, Filippo; Masetti, Nicola; Orlandini, Mauro; Palazzi, Eliana; Sordo, Stefano Del; Santangelo, Andrea; Segreto, Alberto; Oosterbroek, Tim; Parmar, Arvind N.
2000-01-01
The systematic search for the presence of cyclotron lines in the spectra ofaccreting X-ray pulsars is being carried on with the BeppoSAX satellite sincethe beginning of the mission. These highly successful observations allowed thedetection of cyclotron lines in many of the accreting X-ray pulsars observed.Some correlations between the different measured parameters were found. Wepresent these correlations and discuss them in the framework of the currenttheoretical scenario for the X-ray emission from these sources.
Keenan, Brett; Ford, Alex; Medvedev, Mikhail
2014-10-01
Plasma turbulence in some astrophysical objects (e.g., weakly magnetized collisionless shocks in GRBs and SN) has small-scale electro-magnetic field fluctuations. We study spectral characteristics of radiation produced by particles moving in such turbulence and relate it to transport properties (diffusion) of these particles. It was shown earlier that relativistic particles produce jitter radiation, which spectral characteristics are markedly different from synchrotron radiation. Here we study radiation produced by non-relativistic particles. Unlike radiation in homogeneous field, which spectrum consists of a single cyclotron harmonic, radiation in the sub-Larmor-scale turbulence reflects statistical properties of the underlying magnetic field. We present both analytical estimates and results of ab initio numerical simulations. We also show that particle propagation in such turbulence is diffusive and evaluate the diffusion coefficient. We demonstrate that the diffusion coefficient correlates with some spectral parameters. These results can be very valuable for remote diagnostics of laboratory and astrophysical plasmas. Supported by grant DOE grant DE-FG02-07ER54940 and NSF grant AST-1209665.
Surprises with Nonrelativistic Naturalness
Horava, Petr
2016-01-01
We explore the landscape of technical naturalness for nonrelativistic systems, finding surprises which challenge and enrich our relativistic intuition already in the simplest case of a single scalar field. While the immediate applications are expected in condensed matter and perhaps in cosmology, the study is motivated by the leading puzzles of fundamental physics involving gravity: The cosmological constant problem and the Higgs mass hierarchy problem.
Westerhof, E.
1994-01-01
The essential elements of the theory of electron cyclotron waves are reviewed, The two main electro-magnetic modes of propagation are identified and their dispersion and absorption properties are discussed. The importance of the use of the relativistic resonance condition is stressed.
Cyclotron resonant interactions in cosmic particle accelerators
Terasawa, T; 10.1007/s11214-012-9878-0
2012-01-01
A review is given for cyclotron resonant interactions in space plasmas. After giving a simple formulation for the test particle approach, illustrative examples for resonant interactions are given. It is shown that for obliquely propagating whistler waves, not only fundamental cyclotron resonance, but also other resonances, such as transit-time resonance, anomalous cyclotron resonance, higher-harmonic cyclotron resonance, and even subharmonic resonance can come into play. A few recent topics of cyclotron resonant interactions, such as electron injection in shocks, cyclotron resonant heating of solar wind heavy ions, and relativistic modifications, are also reviewed.
DEFF Research Database (Denmark)
Leahu, Lucian
2016-01-01
This paper investigates how we might rethink design as the technological crafting of human-machine relations in the context of a machine learning technique called neural networks. It analyzes Google’s Inceptionism project, which uses neural networks for image recognition. The surprising output of...... a hybrid approach where machine learning algorithms are used to identify objects as well as connections between them; finally, it argues for remaining open to ontological surprises in machine learning as they may enable the crafting of different relations with and through technologies....
DEFF Research Database (Denmark)
Korn, Matthias; Kawash, Raghid; Andersen, Lisbet Møller
We report on a platform that augments the natural experience of exploration in diverse indoor and outdoor environments. The system builds on the theme of surprises in terms of user expectations and finding points of interest. It utilizes physical icons as representations of users' interests and a...
Antonella Del Rosso
2011-01-01
The CP violation in charm quarks has always been thought to be extremely small. So, looking at particle decays involving matter and antimatter, the LHCb experiment has recently been surprised to observe that things might be different. Theorists are on the case. The study of the physics of the charm quark was not in the initial plans of the LHCb experiment, whose letter “b” stands for “beauty quark”. However, already one year ago, the Collaboration decided to look into a wider spectrum of processes that involve charm quarks among other things. The LHCb trigger allows a lot of these processes to be selected, and, among them, one has recently shown interesting features. Other experiments at b-factories have already performed the same measurement but this is the first time that it has been possible to achieve such high precision, thanks to the huge amount of data provided by the very high luminosity of the LHC. “We have observed the decay modes of t...
Antonella Del Rosso
2011-01-01
The CP violation in charm quarks has always been thought to be extremely small. So, looking at particle decays involving matter and antimatter, the LHCb experiment has recently been surprised to observe that things might be different. Theorists are on the case. The study of the physics of the charm quark was not in the initial plans of the LHCb experiment, whose letter “b” stands for “beauty quark”. However, already one year ago, the Collaboration decided to look into a wider spectrum of processes that involve charm quarks among other things. The LHCb trigger allows a lot of these processes to be selected, and, among them, one has recently shown interesting features. Other experiments at b-factories have already performed the same measurement but this is the first time that it has been possible to achieve such high precision, thanks to the huge amount of data provided by the very high luminosity of the LHC. “We have observed the decay modes of the D0, a pa...
Energy Technology Data Exchange (ETDEWEB)
Martin, J.A. (comp.)
1978-01-01
A compilation is presented of the experimental facilities of the world's cyclotrons including history and status, staff and operation, research staff, target facilities, magnet, acceleration system, vacuum system, characteristic beams, beam properties, and a plan view of the facility for each cyclotron. (GHT)
Energy Technology Data Exchange (ETDEWEB)
Jost, G.; Tran, T.M.; Appert, K. [Ecole Polytechnique Federale, Lausanne (Switzerland). Centre de Recherche en Physique des Plasma (CRPP); Wuethrich, S. [CRAY Research, PATP/PSE, EPFL, Lausanne (Switzerland)
1996-12-01
A two-dimensional PIC code aimed at the investigation of electron-cyclotron beam instabilities in gyrotrons and their effects on the beam quality is presented. The code is based on recently developed techniques for handling charge conservation and open boundaries and uses an electromagnetic field which is decomposed in its transverse magnetic (TM) and electric (TE) components. The code has been implemented on the massively parallel computer CRAY T3D, and on the CRAY Y-MP. (author) figs., tabs., refs.
Energy Technology Data Exchange (ETDEWEB)
Wolf, A P
1976-01-01
Cyclotrons as tools for therapy and for the production of radionuclides for use in nuclear medicine have been extensively reviewed in the literature. The current world status with respect to cyclotrons used primarily for research, development and application in nuclear medicine is reviewed here in the context of geographical distribution and type of use, presently available commercial types, machine characteristics and trends. Aspects of design requirements from a user perspective such as machine, beam and target characteristics are covered. Some special problems concerning many factors which can lead to effective production of the desired radionuclide or product are considered in light of machine characteristics. Consideration is also given to future directions for accelerators in nuclear medicine.
2010-09-24
SEP 2010 2. REPORT TYPE 3. DATES COVERED 00-00-2010 to 00-00-2010 4. TITLE AND SUBTITLE More Supernova Surprises 5a. CONTRACT NUMBER 5b. GRANT...PERSPECTIVES More Supernova Surprises ASTRONOMY J. Martin Laming Spectroscopic observations of the supernova SN1987A are providing a new window into high...a core-collapse supernova ) have stretched and motivated research that has expanded our knowledge of astrophysics. The brightest such event in
Semi-classical quantum theory for cyclotron radiation
Institute of Scientific and Technical Information of China (English)
陈军锋; 邓劲松; 徐毅; 尤峻汉
1997-01-01
A semi-classical quantum theory of the cyclotron radiation of the nonrelativistic thermal electrons in a very strong magnetic field is presented.The basic formulae of the absorption coefficient of cyclotron resonance kv and the absorption (scattering) cross-section of cyclotron resonance σv have been derived under the quadrupole approximation.σv is an important quantity in the study of the "magnetic inverse-Compton scattering".It is shown that σv is greatly larger than the Thomson cross-sectron σT,which is important in discussing the magnetic inverse-Compton scattering of the relativistic electrons in a very strong magnetic field.
The cyclotron maser theory of AKR and Z-mode radiation. [Auroral Kilometric Radiation
Wu, C. S.
1985-01-01
The cyclotron maser mechanism which may be responsible for the generation of auroral kilometric radiation and Z-mode radiation is discussed. Emphasis is placed on the basic concepts of the cyclotron maser theory, particularly the relativistic effect of the cyclotron resonance condition. Recent development of the theory is reviewed. Finally, the results of a computer simulation study which helps to understand the nonlinear saturation of the maser instability are reported.
Lominadze, D G
2013-01-01
Cyclotron Waves in Plasma is a four-chapter text that covers the basic physical concepts of the theory of cyclotron waves and cyclotron instabilities, brought about by the existence of steady or alternating plasma currents flowing perpendicular to the magnetic field.This book considers first a wide range of questions associated with the linear theory of cyclotron oscillations in equilibrium plasmas and in electron plasmas in metals and semiconductors. The next chapter deals with the parametric excitation of electron cyclotron oscillations in plasma in an alternating electric field. A chapter f
Surprises in astrophysical gasdynamics
Balbus, Steven A
2016-01-01
Much of astrophysics consists of the study of ionised gas under the influence of gravitational and magnetic fields. Thus, it is not possible to understand the astrophysical universe without a detailed knowledge of the dynamics of magnetised fluids. Fluid dynamics is, however, a notoriously tricky subject, in which it is all too easy for one's a priori intuition to go astray. In this review, we seek to guide the reader through a series of illuminating yet deceptive problems, all with an enlightening twist. We cover a broad range of topics including the instabilities acting in accretion discs, the hydrodynamics governing the convective zone of the Sun, the magnetic shielding of a cooling galaxy cluster, and the behaviour of thermal instabilities and evaporating clouds. The aim of this review is to surprise and intrigue even veteran astrophysical theorists with an idiosynchratic choice of problems and counterintuitive results. At the same time, we endeavour to bring forth the fundamental ideas, to set out import...
Relativistic Quantum Noninvasive Measurements
Bednorz, Adam
2014-01-01
Quantum weak, noninvasive measurements are defined in the framework of relativity. Invariance with respect to reference frame transformations of the results in different models is discussed. Surprisingly, the bare results of noninvasive measurements are invariant for certain class of models, but not the detection error. Consequently, any stationary quantum realism based on noninvasive measurements will break, at least spontaneously, relativistic invariance and correspondence principle at zero temperature.
Surprises in astrophysical gasdynamics
Balbus, Steven A.; Potter, William J.
2016-06-01
Much of astrophysics consists of the study of ionized gas under the influence of gravitational and magnetic fields. Thus, it is not possible to understand the astrophysical universe without a detailed knowledge of the dynamics of magnetized fluids. Fluid dynamics is, however, a notoriously tricky subject, in which it is all too easy for one’s a priori intuition to go astray. In this review, we seek to guide the reader through a series of illuminating yet deceptive problems, all with an enlightening twist. We cover a broad range of topics including the instabilities acting in accretion discs, the hydrodynamics governing the convective zone of the Sun, the magnetic shielding of a cooling galaxy cluster, and the behaviour of thermal instabilities and evaporating clouds. The aim of this review is to surprise and intrigue even veteran astrophysical theorists with an idiosyncratic choice of problems and counterintuitive results. At the same time, we endeavour to bring forth the fundamental ideas, to set out important assumptions, and to describe carefully whatever novel techniques may be appropriate to the problem at hand. By beginning at the beginning, and analysing a wide variety of astrophysical settings, we seek not only to make this review suitable for fluid dynamic veterans, but to engage novice recruits as well with what we hope will be an unusual and instructive introduction to the subject.
Surprises in astrophysical gasdynamics.
Balbus, Steven A; Potter, William J
2016-06-01
Much of astrophysics consists of the study of ionized gas under the influence of gravitational and magnetic fields. Thus, it is not possible to understand the astrophysical universe without a detailed knowledge of the dynamics of magnetized fluids. Fluid dynamics is, however, a notoriously tricky subject, in which it is all too easy for one's a priori intuition to go astray. In this review, we seek to guide the reader through a series of illuminating yet deceptive problems, all with an enlightening twist. We cover a broad range of topics including the instabilities acting in accretion discs, the hydrodynamics governing the convective zone of the Sun, the magnetic shielding of a cooling galaxy cluster, and the behaviour of thermal instabilities and evaporating clouds. The aim of this review is to surprise and intrigue even veteran astrophysical theorists with an idiosyncratic choice of problems and counterintuitive results. At the same time, we endeavour to bring forth the fundamental ideas, to set out important assumptions, and to describe carefully whatever novel techniques may be appropriate to the problem at hand. By beginning at the beginning, and analysing a wide variety of astrophysical settings, we seek not only to make this review suitable for fluid dynamic veterans, but to engage novice recruits as well with what we hope will be an unusual and instructive introduction to the subject.
Alfven cyclotron instability and ion cyclotron emission
Energy Technology Data Exchange (ETDEWEB)
Gorelenkov, N.N.; Cheng, C.Z.
1995-07-01
Two-dimensional solutions of compressional Alfven eigenmodes (CAE) are studied in the cold plasma approximation. For finite inverse aspect ratio tokamak plasmas the two-dimensional eigenmode envelope is localized at the low magnetic field side with the radial and poloidal localization on the order of a/{radical}m and a/(fourth root of m), respectively, where m is the dominant poloidal mode number. Charged fusion product driven Alfven Cyclotron Instability (ACI) of the compressional Alfven eigenmodes provides the explanation for the ion cyclotron emission (ICE) spectrum observed in tokamak experiments. The ACI is excited by fast charged fusion products via Doppler shifted cyclotron wave-particle resonances. The ion cyclotron and electron Landau dampings and fast particle instability drive are calculated perturbatively for deuterium-deuterium (DD) and deuterium-tritium (DT) plasmas. Near the plasma edge at the low field side the velocity distribution function of charged fusion products is localized in both pitch angle and velocity. The poloidal localization of the eigenmode enhances the ACI growth rates by a factor of {radical}m in comparison with the previous results without poloidal envelope. The thermal ion cyclotron damping determines that only modes with eigenfrequencies at multiples of the edge cyclotron frequency of the background ions can be easily excited and form an ICE spectrum similar to the experimental observations. Theoretical understanding is given for the results of TFTR DD and DT experiments with {upsilon}{sub {alpha}0}/{upsilon}{sub A} < 1 and JET experiments with {upsilon}{sub {alpha}0}/{upsilon}{sub A} > 1.
Demianski, Marek
2013-01-01
Relativistic Astrophysics brings together important astronomical discoveries and the significant achievements, as well as the difficulties in the field of relativistic astrophysics. This book is divided into 10 chapters that tackle some aspects of the field, including the gravitational field, stellar equilibrium, black holes, and cosmology. The opening chapters introduce the theories to delineate gravitational field and the elements of relativistic thermodynamics and hydrodynamics. The succeeding chapters deal with the gravitational fields in matter; stellar equilibrium and general relativity
Cyclotron Institute Upgrade Project
Energy Technology Data Exchange (ETDEWEB)
Clark, Henry [Texas A& M University; Yennello, Sherry [Texas A& M University; Tribble, Robert [Texas A& M University
2014-08-26
The Cyclotron Institute at Texas A&M University has upgraded its accelerator facilities to extend research capabilities with both stable and radioactive beams. The upgrade is divided into three major tasks: (1) re-commission the K-150 (88”) cyclotron, couple it to existing beam lines to provide intense stable beams into the K-500 experimental areas and use it as a driver to produce radioactive beams; (2) develop light ion and heavy ion guides for stopping radioactive ions created with the K-150 beams; and (3) transport 1+ ions from the ion guides into a charge-breeding electron-cyclotron-resonance ion source (CB-ECR) to produce highly-charged radioactive ions for acceleration in the K-500 cyclotron. When completed, the upgraded facility will provide high-quality re-accelerated secondary beams in a unique energy range in the world.
CERN PhotoLab
1972-01-01
The electromagnetic coil which forms the first section of the proton extraction channel in the improved synchro-cyclotron. The photograph shows the positioning gear and the current septum. An extraction efficiency above 50% is expected.
Lawson, J D
1966-01-01
Article describing how valuable scientific work can still be carried out with the smaller energy cyclotrons such as those at the Radiochemical Centre, Amersham and the Atomic Energy Research Establishment, Harwell (2 pages).
Acceleration of positrons by a relativistic electron beam in the presence of quantum effects
Energy Technology Data Exchange (ETDEWEB)
Niknam, A. R. [Laser and Plasma Research Institute, Shahid Beheshti University, G.C., Tehran (Iran, Islamic Republic of); Aki, H.; Khorashadizadeh, S. M. [Physics Department, Birjand University, Birjand (Iran, Islamic Republic of)
2013-09-15
Using the quantum magnetohydrodynamic model and obtaining the dispersion relation of the Cherenkov and cyclotron waves, the acceleration of positrons by a relativistic electron beam is investigated. The Cherenkov and cyclotron acceleration mechanisms of positrons are compared together. It is shown that growth rate and, therefore, the acceleration of positrons can be increased in the presence of quantum effects.
J. Vanhamme (Joëlle)
2003-01-01
textabstractThis research investigates the specific influence of the emotion of surprise on customer transaction-specific satisfaction. Four empirical studies-two field studies (a diary study and a cross section survey) and two experiments-were conducted. The results show that surprise positively
J. Vanhamme (Joëlle)
2003-01-01
textabstractThis research investigates the specific influence of the emotion of surprise on customer transaction-specific satisfaction. Four empirical studies-two field studies (a diary study and a cross section survey) and two experiments-were conducted. The results show that surprise positively [n
Inflation and Cyclotron Motion
Greensite, Jeff
2016-01-01
We consider, in the context of a braneworld cosmology, the motion of the universe coupled to a four-form gauge field, with constant field strength, defined in higher dimensions. It is found, under rather general initial conditions, that in this situation there is a period of exponential inflation combined with cyclotron motion in the inflaton field space. The main effect of the cyclotron motion is that conditions on the flatness of the inflaton potential, which are typically necessary for exponential inflation, can be evaded. There are Landau levels associated with the four-form gauge field, and these correspond to quantum excitations of the inflaton field.
1974-01-01
Final touches to the central region of SC2, the refurbished 600 MeV synchro-cyclotron, before the start of commissioning. Modifications included a new type of ion source at the centre. Protons were first accelerated in SC2 at full energy by October 1974. (See photo 7408042X)
Conceptual Design Study of 13 MeV Proton Cyclotron
Directory of Open Access Journals (Sweden)
Silakhuddin
2012-04-01
Full Text Available A study to determine the conceptual design of a 13 MeV proton cyclotron for PET (Positron Emission Tomography facility has been carried out. Based on studies on reactions of PET radioisotopes production, reaction cross-sections and some design references, a design of the proton cyclotron is proposed. The design criteria for the main components are decided using empirical and semitheoretical methods, as well as by referring to data regarding cyclotrons for PET production. The empirical method was carried out by using some data from operational experiences of BATAN cyclotron at Serpong, while the semitheoretical method was carried out by using the commonly used equations of cyclotron basic theory. The general layout of components and the main components, namely the ion source, the RF dees, the magnet, and the extractor are discussed. Based on the calculations and on the data used, the cyclotron is designed as a negative ion acceleration cyclotron with internal ion source. The designated proton energy and beam currents are 13 MeV and 50 µA. Its magnetic field is in the relativistic mode with sectors on the pole. The magnetic field intensity at the extraction radius is 12.745 kG and in the innermost radius is 12.571 kG. The magnetic poles consist of four sectors to make adequate space for components placement such as dees, ion source, extractor and beam probe. The dee angle is 430. The dee operates at 78 MHz on the fourth harmonic. A multifoil extractor is chosen to obtain an efficient operation
Ludden, G.D.S.; Schifferstein, H.N.J.; Hekkert, P.P.M.
2008-01-01
Imagine yourself queuing for the cashier’s desk in a supermarket. Naturally, you have picked the wrong line, the one that does not seem to move at all. Soon, you get tired of waiting. Now, how would you feel if the cashier suddenly started to sing? Many of us would be surprised and, regardless of
Ludden, G.D.S.; Schifferstein, H.N.J.; Hekkert, P.P.M.
2008-01-01
Imagine yourself queuing for the cashier’s desk in a supermarket. Naturally, you have picked the wrong line, the one that does not seem to move at all. Soon, you get tired of waiting. Now, how would you feel if the cashier suddenly started to sing? Many of us would be surprised and, regardless of th
Luciano, Rezzolla
2013-01-01
Relativistic hydrodynamics is a very successful theoretical framework to describe the dynamics of matter from scales as small as those of colliding elementary particles, up to the largest scales in the universe. This book provides an up-to-date, lively, and approachable introduction to the mathematical formalism, numerical techniques, and applications of relativistic hydrodynamics. The topic is typically covered either by very formal or by very phenomenological books, but is instead presented here in a form that will be appreciated both by students and researchers in the field. The topics covered in the book are the results of work carried out over the last 40 years, which can be found in rather technical research articles with dissimilar notations and styles. The book is not just a collection of scattered information, but a well-organized description of relativistic hydrodynamics, from the basic principles of statistical kinetic theory, down to the technical aspects of numerical methods devised for the solut...
Electron Cyclotron Emission Radiometer
Morales, Cristina
2009-11-01
There is much interest in studying plasmas that generate hot electrons. The goal of this project is to develop a wide band electron cyclotron radiometer to measure the non-Maxwellian rapid rises in electron temperature. These rapid increases in temperature will then be correlated to instabilities in the plasma. This project explores a type of noncontact temperature measurement. We will attempt to show the feasibility of electron cyclotron emissions to measure the Maryland Centrifugal Experiment's electron plasma temperature. The radiometer has been designed to have 100dB of gain and a sensitivity of 24mV/dB given by its logarithmic amplifier. If successful, this radiometer will be used as a diagnostic tool in later projects such as the proposed experiment studying magnetic reconnection using solar flux loops.
Electron cyclotron resonance heating and current drive
Energy Technology Data Exchange (ETDEWEB)
Fidone, I.; Castejon, F.
1992-07-01
A brief summary of the theory and experiments on electron- cyclotron heating and current drive is presented. The general relativistic formulation of wave propagation and linear absorption is considered in some detail. The O-mode and the X-mode for normal and oblique propagation are investigated and illustrated by several examples. The experimental verification of the theory in T-10 and D- III-D is briefly discussed. Quasilinear evolution of the momentum distribution and related applications as, for instance, non linear wave, damping and current drive, are also considered for special cases of wave frequencies, polarization and propagation. In the concluding section we present the general formulation of the wave damping and current drive in the absence of electron trapping for arbitrary values of the wave frequency. (Author) 13 refs.
Haba, Z
2009-02-01
We discuss relativistic diffusion in proper time in the approach of Schay (Ph.D. thesis, Princeton University, Princeton, NJ, 1961) and Dudley [Ark. Mat. 6, 241 (1965)]. We derive (Langevin) stochastic differential equations in various coordinates. We show that in some coordinates the stochastic differential equations become linear. We obtain momentum probability distribution in an explicit form. We discuss a relativistic particle diffusing in an external electromagnetic field. We solve the Langevin equations in the case of parallel electric and magnetic fields. We derive a kinetic equation for the evolution of the probability distribution. We discuss drag terms leading to an equilibrium distribution. The relativistic analog of the Ornstein-Uhlenbeck process is not unique. We show that if the drag comes from a diffusion approximation to the master equation then its form is strongly restricted. The drag leading to the Tsallis equilibrium distribution satisfies this restriction whereas the one of the Jüttner distribution does not. We show that any function of the relativistic energy can be the equilibrium distribution for a particle in a static electric field. A preliminary study of the time evolution with friction is presented. It is shown that the problem is equivalent to quantum mechanics of a particle moving on a hyperboloid with a potential determined by the drag. A relation to diffusions appearing in heavy ion collisions is briefly discussed.
Sahoo, Raghunath
2016-01-01
This lecture note covers Relativistic Kinematics, which is very useful for the beginners in the field of high-energy physics. A very practical approach has been taken, which answers "why and how" of the kinematics useful for students working in the related areas.
Mihara, Tatehiro; Nagase, Fumiaki
2014-01-01
We systematically analyzed the spectra of X-ray binary pulsars observed with GINGA (Mihara 1995). A new model NPEX (Negative and Positive power-laws EXponential) was introduced t o represent the pulsar continuum. Combining the NPEX continuum with the CYAB factor (cyclotron resonance scattering model), we successfully fit the whole-band spectra of all the pulsars. A possible physical meaning of the NPEX model is the Comptonized spectra. By using the smooth and concave NPEX model, the cyclotron structures were detected from 12 pulsars, about a half of the 23 sources, including new discoveries from LMC X-4 and GS 1843+00. The magnetic fields were scattered in the range of $3\\times10^{11}$ - $5\\times10^{12}$ G. The distribution was shown for the first time, which is remarkably similar to that of radio pulsars with a peak at $2 \\times 10^{12}$ G. The double harmonic cyclotron structures of 4U 0115+63 in 1990 changed to a sin gle structure in 1991. The resonance energy also increased by 40 % as the luminosity decre...
Brazilian rescue plan sparks surprise
Institute of Scientific and Technical Information of China (English)
2011-01-01
According to Financial Times,when Guido Mantega,Brazil's finance minister,suddenly proposed a “Bric” rescue package for the eurozone this week,he caught not only other world leaders by surprise but also many of his fellow countrymen.Even as officials from other members of the so-called Bric grouping,Russia,India and China,said it was the first they heard of the idea,many ordinary Brazilians expressed shock at the notion of bailing out the world's richest trading bloc.
Hakim, Rémi
1994-01-01
Il existe à l'heure actuelle un certain nombre de théories relativistes de la gravitation compatibles avec l'expérience et l'observation. Toutefois, la relativité générale d'Einstein fut historiquement la première à fournir des résultats théoriques corrects en accord précis avec les faits.
Jones, Bernard J. T.; Markovic, Dragoljub
1997-06-01
Preface; Prologue: Conference overview Bernard Carr; Part I. The Universe At Large and Very Large Redshifts: 2. The size and age of the Universe Gustav A. Tammann; 3. Active galaxies at large redshifts Malcolm S. Longair; 4. Observational cosmology with the cosmic microwave background George F. Smoot; 5. Future prospects in measuring the CMB power spectrum Philip M. Lubin; 6. Inflationary cosmology Michael S. Turner; 7. The signature of the Universe Bernard J. T. Jones; 8. Theory of large-scale structure Sergei F. Shandarin; 9. The origin of matter in the universe Lev A. Kofman; 10. New guises for cold-dark matter suspects Edward W. Kolb; Part II. Physics and Astrophysics Of Relativistic Compact Objects: 11. On the unification of gravitational and inertial forces Donald Lynden-Bell; 12. Internal structure of astrophysical black holes Werner Israel; 13. Black hole entropy: external facade and internal reality Valery Frolov; 14. Accretion disks around black holes Marek A. Abramowicz; 15. Black hole X-ray transients J. Craig Wheeler; 16. X-rays and gamma rays from active galactic nuclei Roland Svensson; 17. Gamma-ray bursts: a challenge to relativistic astrophysics Martin Rees; 18. Probing black holes and other exotic objects with gravitational waves Kip Thorne; Epilogue: the past and future of relativistic astrophysics Igor D. Novikov; I. D. Novikov's scientific papers and books.
Wave-induced loss of ultra-relativistic electrons in the Van Allen radiation belts
Shprits, Yuri Y.; Drozdov, Alexander Y.; Spasojevic, Maria; Kellerman, Adam C.; Usanova, Maria E.; Engebretson, Mark J.; Agapitov, Oleksiy V.; Zhelavskaya, Irina S.; Raita, Tero J.; Spence, Harlan E.; Baker, Daniel N.; Zhu, Hui; Aseev, Nikita A.
2016-01-01
The dipole configuration of the Earth's magnetic field allows for the trapping of highly energetic particles, which form the radiation belts. Although significant advances have been made in understanding the acceleration mechanisms in the radiation belts, the loss processes remain poorly understood. Unique observations on 17 January 2013 provide detailed information throughout the belts on the energy spectrum and pitch angle (angle between the velocity of a particle and the magnetic field) distribution of electrons up to ultra-relativistic energies. Here we show that although relativistic electrons are enhanced, ultra-relativistic electrons become depleted and distributions of particles show very clear telltale signatures of electromagnetic ion cyclotron wave-induced loss. Comparisons between observations and modelling of the evolution of the electron flux and pitch angle show that electromagnetic ion cyclotron waves provide the dominant loss mechanism at ultra-relativistic energies and produce a profound dropout of the ultra-relativistic radiation belt fluxes. PMID:27678050
Wave-induced loss of ultra-relativistic electrons in the Van Allen radiation belts.
Shprits, Yuri Y; Drozdov, Alexander Y; Spasojevic, Maria; Kellerman, Adam C; Usanova, Maria E; Engebretson, Mark J; Agapitov, Oleksiy V; Zhelavskaya, Irina S; Raita, Tero J; Spence, Harlan E; Baker, Daniel N; Zhu, Hui; Aseev, Nikita A
2016-09-28
The dipole configuration of the Earth's magnetic field allows for the trapping of highly energetic particles, which form the radiation belts. Although significant advances have been made in understanding the acceleration mechanisms in the radiation belts, the loss processes remain poorly understood. Unique observations on 17 January 2013 provide detailed information throughout the belts on the energy spectrum and pitch angle (angle between the velocity of a particle and the magnetic field) distribution of electrons up to ultra-relativistic energies. Here we show that although relativistic electrons are enhanced, ultra-relativistic electrons become depleted and distributions of particles show very clear telltale signatures of electromagnetic ion cyclotron wave-induced loss. Comparisons between observations and modelling of the evolution of the electron flux and pitch angle show that electromagnetic ion cyclotron waves provide the dominant loss mechanism at ultra-relativistic energies and produce a profound dropout of the ultra-relativistic radiation belt fluxes.
Wave-induced loss of ultra-relativistic electrons in the Van Allen radiation belts
Shprits, Yuri Y.; Drozdov, Alexander Y.; Spasojevic, Maria; Kellerman, Adam C.; Usanova, Maria E.; Engebretson, Mark J.; Agapitov, Oleksiy V.; Zhelavskaya, Irina S.; Raita, Tero J.; Spence, Harlan E.; Baker, Daniel N.; Zhu, Hui; Aseev, Nikita A.
2016-09-01
The dipole configuration of the Earth's magnetic field allows for the trapping of highly energetic particles, which form the radiation belts. Although significant advances have been made in understanding the acceleration mechanisms in the radiation belts, the loss processes remain poorly understood. Unique observations on 17 January 2013 provide detailed information throughout the belts on the energy spectrum and pitch angle (angle between the velocity of a particle and the magnetic field) distribution of electrons up to ultra-relativistic energies. Here we show that although relativistic electrons are enhanced, ultra-relativistic electrons become depleted and distributions of particles show very clear telltale signatures of electromagnetic ion cyclotron wave-induced loss. Comparisons between observations and modelling of the evolution of the electron flux and pitch angle show that electromagnetic ion cyclotron waves provide the dominant loss mechanism at ultra-relativistic energies and produce a profound dropout of the ultra-relativistic radiation belt fluxes.
Polarization in cyclotron radiation in strong magnetic fields
Institute of Scientific and Technical Information of China (English)
Luidmila Semionova; Denis Leahy; Jorge Paez
2010-01-01
We revisit the problem of radiative transitions of electrons in the presence of a strong magnetic field.We derive fully relativistic cyclotron transition rates for an arbitrary magnetic field,for any orientation of electron spin and for any polarization of the emitted radiation.Also,we obtain the transition rates for any value of the initial electron's parallel momentum.For very strong magnetic fields,transitions to the ground state predominate.Transition rates summed over the electron's spin orientation and for unpolarized radiation are also obtained,which confirm previous results by Latal.Transition widths are calculated for different electron spin orientations and different polarizations of radiation.We obtain general expressions for transition rates that reduce to the results for the non-relativistic case and for unpolarized radiation.Additionally we get,for the non-relativistic approximation,the transition rates for any polarization of radiation.As an application,the first five emission lines are evaluated and compared to the X-ray emitting neutron star V0332+53,which has multiple observable cyclotron lines,taking into account gravitational redshift.The most probable polarization is ∈(2).
Cyclotrons and positron emitting radiopharmaceuticals
Energy Technology Data Exchange (ETDEWEB)
Wolf, A.P.; Fowler, J.S.
1984-01-01
The state of the art of Positron Emission Tomography (PET) technology as related to cyclotron use and radiopharmaceutical production is reviewed. The paper discusses available small cyclotrons, the positron emitters which can be produced and the yields possible, target design, and radiopharmaceutical development and application. 97 refs., 12 tabs. (ACR)
A relativistic trolley paradox
Matvejev, Vadim N.; Matvejev, Oleg V.; Grøn, Ø.
2016-06-01
We present an apparent paradox within the special theory of relativity, involving a trolley with relativistic velocity and its rolling wheels. Two solutions are given, both making clear the physical reality of the Lorentz contraction, and that the distance on the rails between each time a specific point on the rim touches the rail is not equal to 2 π R , where R is the radius of the wheel, but 2 π R / √{ 1 - R 2 Ω 2 / c 2 } , where Ω is the angular velocity of the wheels. In one solution, the wheel radius is constant as the velocity of the trolley increases, and in the other the wheels contract in the radial direction. We also explain two surprising facts. First that the shape of a rolling wheel is elliptical in spite of the fact that the upper part of the wheel moves faster than the lower part, and thus is more Lorentz contracted, and second that a Lorentz contracted wheel with relativistic velocity rolls out a larger distance between two successive touches of a point of the wheel on the rails than the length of a circle with the same radius as the wheels.
Relativistic quantum information
Mann, R. B.; Ralph, T. C.
2012-11-01
Over the past few years, a new field of high research intensity has emerged that blends together concepts from gravitational physics and quantum computing. Known as relativistic quantum information, or RQI, the field aims to understand the relationship between special and general relativity and quantum information. Since the original discoveries of Hawking radiation and the Unruh effect, it has been known that incorporating the concepts of quantum theory into relativistic settings can produce new and surprising effects. However it is only in recent years that it has become appreciated that the basic concepts involved in quantum information science undergo significant revision in relativistic settings, and that new phenomena arise when quantum entanglement is combined with relativity. A number of examples illustrate that point. Quantum teleportation fidelity is affected between observers in uniform relative acceleration. Entanglement is an observer-dependent property that is degraded from the perspective of accelerated observers moving in flat spacetime. Entanglement can also be extracted from the vacuum of relativistic quantum field theories, and used to distinguish peculiar motion from cosmological expansion. The new quantum information-theoretic framework of quantum channels in terms of completely positive maps and operator algebras now provides powerful tools for studying matters of causality and information flow in quantum field theory in curved spacetimes. This focus issue provides a sample of the state of the art in research in RQI. Some of the articles in this issue review the subject while others provide interesting new results that will stimulate further research. What makes the subject all the more exciting is that it is beginning to enter the stage at which actual experiments can be contemplated, and some of the articles appearing in this issue discuss some of these exciting new developments. The subject of RQI pulls together concepts and ideas from
Relativistic and non-relativistic geodesic equations
Energy Technology Data Exchange (ETDEWEB)
Giambo' , R.; Mangiarotti, L.; Sardanashvily, G. [Camerino Univ., Camerino, MC (Italy). Dipt. di Matematica e Fisica
1999-07-01
It is shown that any dynamic equation on a configuration space of non-relativistic time-dependent mechanics is associated with connections on its tangent bundle. As a consequence, every non-relativistic dynamic equation can be seen as a geodesic equation with respect to a (non-linear) connection on this tangent bundle. Using this fact, the relationships between relativistic and non-relativistic equations of motion is studied.
Energy Technology Data Exchange (ETDEWEB)
Efthimion, P.C.; Arunasalam, V.; Hosea, J.C.
1979-11-01
Fundamental electron cyclotron resonance damping for 4 mm waves with ordinary polarization is measured for propagation along the major radius traversing the midplane of the plasma in the Princeton Large Torus (PLT). Optical depths obtained from the data are in good agreement with those predicted by the relativistic hot plasma theory. Near blackbody emission over much of the plasma midplane is obtained and, in conjunction with the damping measurements, indicates that the vessel reflectivity is high. The practical use of ordinary mode fundamental electron cyclotron resonance heating (ECRH) in existing and future toroidal devices is supported by these results.
Some Surprising Introductory Physics Facts and Numbers
Mallmann, A. James
2016-01-01
In the entertainment world, people usually like, and find memorable, novels, short stories, and movies with surprise endings. This suggests that classroom teachers might want to present to their students examples of surprising facts associated with principles of physics. Possible benefits of finding surprising facts about principles of physics are…
EC-5 fifth international workshop on electron cyclotron emission and electron cyclotron heating
Energy Technology Data Exchange (ETDEWEB)
Prater, R.; Lohr, J. [eds.
1985-12-31
This report contains papers on the following topics: electron cyclotron emission measurements; electron cyclotron emission theory; electron cyclotron heating; gyrotron development; and ECH systems and waveguide development. These paper have been indexed separately elsewhere. (LSP).
BEST medical radioisotope production cyclotrons
Sabaiduc, Vasile; Milton, Bruce; Suthanthiran, Krishnan; Gelbart, W. Z.; Johnson, Richard R.
2013-04-01
Best Cyclotron Systems Inc (BCSI) is currently developing 14 MeV, 25 MeV, 35MeV and 70MeV cyclotrons for radioisotope production and research applications as well as the entire spectrum of targets and nuclear synthesis modules for the production of Positron Emission Tomography (PET), Single Photon Emission Computed Tomography (SPECT) and radiation therapy isotopes. The company is a subsidiary of Best Medical International, renowned in the field of medical instrumentation and radiation therapy. All cyclotrons have external negative hydrogen ion sources, four radial sectors with two dees in opposite valleys, cryogenic vacuum system and simultaneous beam extraction on opposite lines. The beam intensity ranges from 400 μA to 1000 μA, depending on the cyclotron energy and application [1].
Spiral Inflector For Compact Cyclotron
Karamysheva, G A
2004-01-01
Compact cyclotron for explosives detection by nuclear resonance absorption of γ-rays in nitrogen is under development [1] Cyclotron will be equipped with the external ion source. The injection system consists of a double-drift beam bunching system, a spiral inflector, beam diagnostics, focusing and adjustment elements [2]. The spiral inflector for ion bending from axial to median plane is used. Computer model of spiral inflector for the Customs cyclotron is developed. 3D electrostatic field calculations of the designed inflector are performed. Calculated electric field map and magnetic field map of the cyclotron [3] are used for beam dynamic simulations. Numeric simulations are carried out for 500 particles using code for calculation of particle dynamics by integration of differential equations in Cartesian coordinate system written in MATLAB. Direct Coulomb particle-to-particle method is used to take into account space-charge effects.
Ion Cyclotron Resonance Facility (ICR)
Federal Laboratory Consortium — his facility is charged with developing and exploiting the unique capabilities of Fourier Transform Ion Cyclotron Resonance (FT-ICR) mass spectrometry, and leads the...
Relativistic magnetohydrodynamics
Hernandez, Juan; Kovtun, Pavel
2017-05-01
We present the equations of relativistic hydrodynamics coupled to dynamical electromagnetic fields, including the effects of polarization, electric fields, and the derivative expansion. We enumerate the transport coefficients at leading order in derivatives, including electrical conductivities, viscosities, and thermodynamic coefficients. We find the constraints on transport coefficients due to the positivity of entropy production, and derive the corresponding Kubo formulas. For the neutral state in a magnetic field, small fluctuations include Alfvén waves, magnetosonic waves, and the dissipative modes. For the state with a non-zero dynamical charge density in a magnetic field, plasma oscillations gap out all propagating modes, except for Alfvén-like waves with a quadratic dispersion relation. We relate the transport coefficients in the "conventional" magnetohydrodynamics (formulated using Maxwell's equations in matter) to those in the "dual" version of magnetohydrodynamics (formulated using the conserved magnetic flux).
Leardini, Fabrice
2013-01-01
This manuscript presents a problem on special relativity theory (SRT) which embodies an apparent paradox relying on the concept of simultaneity. The problem is represented in the framework of Greek epic poetry and structured in a didactic way. Owing to the characteristic properties of Lorenz transformations, three events which are simultaneous in a given inertial reference system, occur at different times in the other two reference frames. In contrast to the famous twin paradox, in the present case there are three, not two, different inertial observers. This feature provides a better framework to expose some of the main characteristics of SRT, in particular, the concept of velocity and the relativistic rule of addition of velocities.
Single electron relativistic clock interferometer
Bushev, P. A.; Cole, J. H.; Sholokhov, D.; Kukharchyk, N.; Zych, M.
2016-09-01
Although time is one of the fundamental notions in physics, it does not have a unique description. In quantum theory time is a parameter ordering the succession of the probability amplitudes of a quantum system, while according to relativity theory each system experiences in general a different proper time, depending on the system's world line, due to time dilation. It is therefore of fundamental interest to test the notion of time in the regime where both quantum and relativistic effects play a role, for example, when different amplitudes of a single quantum clock experience different magnitudes of time dilation. Here we propose a realization of such an experiment with a single electron in a Penning trap. The clock can be implemented in the electronic spin precession and its time dilation then depends on the radial (cyclotron) state of the electron. We show that coherent manipulation and detection of the electron can be achieved already with present day technology. A single electron in a Penning trap is a technologically ready platform where the notion of time can be probed in a hitherto untested regime, where it requires a relativistic as well as quantum description.
Young Galaxy's Magnetism Surprises Astronomers
2008-10-01
Astronomers have made the first direct measurement of the magnetic field in a young, distant galaxy, and the result is a big surprise. Looking at a faraway protogalaxy seen as it was 6.5 billion years ago, the scientists measured a magnetic field at least 10 times stronger than that of our own Milky Way. They had expected just the opposite. The GBT Robert C. Byrd Green Bank Telescope CREDIT: NRAO/AUI/NSF The scientists made the discovery using the National Science Foundation's ultra-sensitive Robert C. Byrd Green Bank Telescope (GBT) in West Virginia. "This new measurement indicates that magnetic fields may play a more important role in the formation and evolution of galaxies than we have realized," said Arthur Wolfe, of the University of California-San Diego (UCSD). At its great distance, the protogalaxy is seen as it was when the Universe was about half its current age. According to the leading theory, cosmic magnetic fields are generated by the dynamos of rotating galaxies -- a process that would produce stronger fields with the passage of time. In this scenario, the magnetic fields should be weaker in the earlier Universe, not stronger. The new, direct magnetic-field measurement comes on the heels of a July report by Swiss and American astronomers who made indirect measurements that also implied strong magnetic fields in the early Universe. "Our results present a challenge to the dynamo model, but they do not rule it out," Wolfe said. There are other possible explanations for the strong magnetic field seen in the one protogalaxy Wolfe's team studied. "We may be seeing the field close to the central region of a massive galaxy, and we know such fields are stronger toward the centers of nearby galaxies. Also, the field we see may have been amplified by a shock wave caused by the collision of two galaxies," he said. The protogalaxy studied with the GBT, called DLA-3C286, consists of gas with little or no star formation occurring in it. The astronomers suspect that
Multicavity proton cyclotron accelerator
Directory of Open Access Journals (Sweden)
J. L. Hirshfield
2002-08-01
Full Text Available A mechanism for acceleration of protons is described, in which energy gain occurs near cyclotron resonance as protons drift through a sequence of rotating-mode TE_{111} cylindrical cavities in a strong nearly uniform axial magnetic field. Cavity resonance frequencies decrease in sequence from one another with a fixed frequency interval Δf between cavities, so that synchronism can be maintained between the rf fields and proton bunches injected at intervals of 1/Δf. An example is presented in which a 122 mA, 1 MeV proton beam is accelerated to 961 MeV using a cascade of eight cavities in an 8.1 T magnetic field, with the first cavity resonant at 120 MHz and with Δf=8 MHz. Average acceleration gradient exceeds 40 MV/m, average effective shunt impedance is 223 MΩ/m, but maximum surface field in the cavities does not exceed 7.2 MV/m. These features occur because protons make many orbital turns in each cavity and thus experience acceleration from each cavity field many times. Longitudinal and transverse stability appear to be intrinsic properties of the acceleration mechanism, and an example to illustrate this is presented. This acceleration concept could be developed into a proton accelerator for a high-power neutron spallation source, such as that required for transmutation of nuclear waste or driving a subcritical fission burner, provided a number of significant practical issues can be addressed.
CSIR cyclotron modified for radiotherapy
Energy Technology Data Exchange (ETDEWEB)
National Accelerator Centre (NAC) staff members will be making an important contribution to radiation therapy in South Africa when the Transvaal Department of Hospital Services starts treating certain types of cancer with fast neutrons, at the Pretoria Cyclotron on the CSIR campus. The fast neutrons will be utilized mainly to treat advanced cancers of the head and the neck. The project will develop along two lines. Firstly the Pretoria cyclotron must be modified and secondly satisfactory radiobiological data must be provided before patients may be treated. This radiobiological experiment heralds a new area for use of the cyclotron which has thus far been used mainly for basic nuclear research and the production of isotopes.
Energy Technology Data Exchange (ETDEWEB)
Qaim, S.M. E-mail: s.m.qaim@fz-juelich.de
2004-11-01
Cyclotrons are versatile ion-accelerating machines which find many applications in medicine. In this short review their use in hadron therapy is briefly discussed. Proton therapy is gaining significance because of its capability to treat deep-lying tumours. A strong area of application of cyclotrons involves the production of short-lived neutron deficient radiotracers for use in emission tomography, especially positron emission tomography. This fast and quantitative in vivo diagnostic technique is being increasingly used in neurology, cardiology and oncology. Besides routine patient care, considerable interdisciplinary work on development of new positron emitters is under way. A short account of those efforts is given. The use of cyclotrons in the production of radionuclides for internal radiotherapy is also briefly described.
Evaluative Appraisals of Environmental Mystery and Surprise
Nasar, Jack L.; Cubukcu, Ebru
2011-01-01
This study used a desktop virtual environment (VE) of 15 large-scale residential streets to test the effects of environmental mystery and surprise on response. In theory, mystery and surprise should increase interest and visual appeal. For each VE, participants walked through an approach street and turned right onto a post-turn street. We designed…
Evaluative Appraisals of Environmental Mystery and Surprise
Nasar, Jack L.; Cubukcu, Ebru
2011-01-01
This study used a desktop virtual environment (VE) of 15 large-scale residential streets to test the effects of environmental mystery and surprise on response. In theory, mystery and surprise should increase interest and visual appeal. For each VE, participants walked through an approach street and turned right onto a post-turn street. We designed…
Analyst Information Precision and Small Earnings Surprises
S. Bissessur; D. Veenman
2014-01-01
Prior research attributes zero and small positive earnings surprises to managers’ incentives for earnings management. In contrast, this study introduces and empirically tests an explanation for zero and small positive earnings surprises based on predictable variation in analyst forecast errors. We a
Cognitive and Social Perspectives on Surprise
Adhami, Mundler
2007-01-01
Meanings of "surprise" are wide and include uplifting and engaging facets like wonder and amazement on the one hand as well as ones that may be of the opposite nature like interruption and disrupt on the other. Pedagogically, educators who use surprise in class activities are focusing on students being "taken aback" by a situation, hopefully…
Energy Technology Data Exchange (ETDEWEB)
Kim, Yu Seok; Chai, Jong Seo; Bak, Seong Ki; Park, Chan Won; Jo, Young Ho; Hong, Seong Seok; Lee, Min Yong; Jang Ho Ha
2000-01-01
The first cyclotron in Korea, MC-50 cyclotron is used for neutron irradiation, radionuclide development, production and material and biomedical research. 50.5MeV and 35MeV proton beam have been extracted with 20-60{mu}A. A total of beam extraction time are 1095.7 hours. 206.5 hours are used for the developments and 663.8 hours are for radionuclide production and development and 225.4 hours for application researches. The shutdown days are 23 days. Fundamental data for failure decrement and efficient beam extraction were composed and maintenance technologies were developed.
On the Relativistic Formulation of Matter
Vishwakarma, Ram Gopal
2012-01-01
A critical analysis of the relativistic formulation of matter reveals some surprising inconsistencies and paradoxes. Corrections are discovered which lead to the long-sought-after equality of the gravitational and inertial masses, which are otherwise different in general relativity. Realizing the potentially great impact of the discovered corrections, an overview of the situation is provided resulting from the newly discovered crisis, amid the evidences defending the theory.
Radiative transfer in ultra-relativistic outflows
Beloborodov, Andrei M.
2010-01-01
Analytical and numerical solutions are obtained for the equation of radiative transfer in ultra-relativistic opaque jets. The solution describes the initial trapping of radiation, its adiabatic cooling, and the transition to transparency. Two opposite regimes are examined: (1) Matter-dominated outflow. Surprisingly, radiation develops enormous anisotropy in the fluid frame before decoupling from the fluid. The radiation is strongly polarized. (2) Radiation-dominated outflow. The transfer occu...
Cattaneo, Carlo
2011-01-01
This title includes: Pham Mau Quam: Problemes mathematiques en hydrodynamique relativiste; A. Lichnerowicz: Ondes de choc, ondes infinitesimales et rayons en hydrodynamique et magnetohydrodynamique relativistes; A.H. Taub: Variational principles in general relativity; J. Ehlers: General relativistic kinetic theory of gases; K. Marathe: Abstract Minkowski spaces as fibre bundles; and, G. Boillat: Sur la propagation de la chaleur en relativite.
Ion sources for cyclotron applications
Energy Technology Data Exchange (ETDEWEB)
Leung, K.N.; Bachman, D.A.; McDonald, D.S.; Young, A.T.
1992-07-01
The use of a multicusp plasma generator as an ion source has many advantages. The development of both positive and negative ion beams based on the multicusp source geometry is presented. It is shown that these sources can be operated at steady state or cw mode. As a result they are very suitable for cyclotron operations.
Status report on cyclotron operation
Kovács, P; Ander, I; Lakatos, T; Fenyvesi, A; Ditrói, F; Takács, S; Tarkanyi, F
2003-01-01
The operation of the cyclotron in 2002 was concentrated to 9 months; January, July and August were reserved for maintenance and holidays. The overall working time of the accelerator was 4084 hours, the breakdown periods amounted to 15 hours last year. In order to improve the circumstances of the irradiations, several following improvements were done. (R.P.)
Relativistic radiative transfer in relativistic spherical flows
Fukue, Jun
2017-02-01
Relativistic radiative transfer in relativistic spherical flows is numerically examined under the fully special relativistic treatment. We first derive relativistic formal solutions for the relativistic radiative transfer equation in relativistic spherical flows. We then iteratively solve the relativistic radiative transfer equation, using an impact parameter method/tangent ray method, and obtain specific intensities in the inertial and comoving frames, as well as moment quantities, and the Eddington factor. We consider several cases; a scattering wind with a luminous central core, an isothermal wind without a core, a scattering accretion on to a luminous core, and an adiabatic accretion on to a dark core. In the typical wind case with a luminous core, the emergent intensity is enhanced at the center due to the Doppler boost, while it reduces at the outskirts due to the transverse Doppler effect. In contrast to the plane-parallel case, the behavior of the Eddington factor is rather complicated in each case, since the Eddington factor depends on the optical depth, the flow velocity, and other parameters.
A toolkit for detecting technical surprise.
Energy Technology Data Exchange (ETDEWEB)
Trahan, Michael Wayne; Foehse, Mark C.
2010-10-01
The detection of a scientific or technological surprise within a secretive country or institute is very difficult. The ability to detect such surprises would allow analysts to identify the capabilities that could be a military or economic threat to national security. Sandia's current approach utilizing ThreatView has been successful in revealing potential technological surprises. However, as data sets become larger, it becomes critical to use algorithms as filters along with the visualization environments. Our two-year LDRD had two primary goals. First, we developed a tool, a Self-Organizing Map (SOM), to extend ThreatView and improve our understanding of the issues involved in working with textual data sets. Second, we developed a toolkit for detecting indicators of technical surprise in textual data sets. Our toolkit has been successfully used to perform technology assessments for the Science & Technology Intelligence (S&TI) program.
Deciphering network community structure by surprise
National Research Council Canada - National Science Library
Aldecoa, Rodrigo; Marín, Ignacio
2011-01-01
.... A fundamental, unsolved problem is how to characterize the community structure of a network. Here, using both standard and novel benchmarks, we show that maximization of a simple global parameter, which we call Surprise...
A Surprising Culprit Behind Celiac Disease?
... news/fullstory_164503.html A Surprising Culprit Behind Celiac Disease? Study suggests harmless viruses may set stage ... typically harmless type of virus might sometimes trigger celiac disease, a new study suggests. Celiac disease is ...
Resonant enhancement of relativistic electron fluxes during geomagnetically active periods
Directory of Open Access Journals (Sweden)
I. Roth
Full Text Available The strong increase in the flux of relativistic electrons during the recovery phase of magnetic storms and during other active periods is investigated with the help of Hamiltonian formalism and simulations of test electrons which interact with whistler waves. The intensity of the whistler waves is enhanced significantly due to injection of 10-100 keV electrons during the substorm. Electrons which drift in the gradient and curvature of the magnetic field generate the rising tones of VLF whistler chorus. The seed population of relativistic electrons which bounce along the inhomogeneous magnetic field, interacts resonantly with the whistler waves. Whistler wave propagating obliquely to the magnetic field can interact with energetic electrons through Landau, cyclotron, and higher harmonic resonant interactions when the Doppler-shifted wave frequency equals any (positive or negative integer multiple of the local relativistic gyrofrequency. Because the gyroradius of a relativistic electron may be the order of or greater than the perpendicular wavelength, numerous cyclotron, harmonics can contribute to the resonant interaction which breaks down the adiabatic invariant. A similar process diffuses the pitch angle leading to electron precipitation. The irreversible changes in the adiabatic invariant depend on the relative phase between the wave and the electron, and successive resonant interactions result in electrons undergoing a random walk in energy and pitch angle. This resonant process may contribute to the 10-100 fold increase of the relativistic electron flux in the outer radiation belt, and constitute an interesting relation between substorm-generated waves and enhancements in fluxes of relativistic electrons during geomagnetic storms and other active periods.
Key words. Magnetospheric physics (energetic particles · trapped; plasma waves and instabilities; storms and substorms
Relativistic Remnants of Non-Relativistic Electrons
Kashiwa, Taro
2015-01-01
Electrons obeying the Dirac equation are investigated under the non-relativistic $c \\mapsto \\infty$ limit. General solutions are given by derivatives of the relativistic invariant functions whose forms are different in the time- and the space-like region, yielding the delta function of $(ct)^2 - x^2$. This light-cone singularity does survive to show that the charge and the current density of electrons travel with the speed of light in spite of their massiveness.
The development of cyclotron radiopharmaceuticals
Energy Technology Data Exchange (ETDEWEB)
Yang, Seung Dae; Chun, K. W.; Suh, Y. S.; Lee, J. D.; Ahn, S. H. and others
1999-03-01
The purpose of this project is to developthe radiopharmaceuticals and automatic synthetic unit for labelled compounds, and to establish mass production system of radiopharmaceuticals. These will contribute to the early diagnosis of the disease hard to cure. The contents of this project are as follows, the development of the radiopharmaceutical for imaging of cancer, the development of automatic synthesizer for the synthesis of radio-pharmaceuticals, the development of hormone derivatives labelled with {sup 12}'3I, the development of the radiopharmaceuticals for therapy of cancer labelled with cyclotron produced radionuclides, the development of radiopharmaceuticals for therapy of cancer labelled with cyclotron produced radionuclides, the development of radiopharmaceuticals for imaging of myocardial metabolism.
Relativistic quantum mechanics
Wachter, Armin
2010-01-01
Which problems do arise within relativistic enhancements of the Schrödinger theory, especially if one adheres to the usual one-particle interpretation, and to what extent can these problems be overcome? And what is the physical necessity of quantum field theories? In many books, answers to these fundamental questions are given highly insufficiently by treating the relativistic quantum mechanical one-particle concept very superficially and instead introducing field quantization as soon as possible. By contrast, this monograph emphasizes relativistic quantum mechanics in the narrow sense: it extensively discusses relativistic one-particle concepts and reveals their problems and limitations, therefore motivating the necessity of quantized fields in a physically comprehensible way. The first chapters contain a detailed presentation and comparison of the Klein-Gordon and Dirac theory, always in view of the non-relativistic theory. In the third chapter, we consider relativistic scattering processes and develop the...
Institute of Scientific and Technical Information of China (English)
ZHANG Peng-Fei; RUAN Tu-Nan
2001-01-01
A systematic theory on the appropriate spin operators for the relativistic states is developed. For a massive relativistic particle with arbitrary nonzero spin, the spin operator should be replaced with the relativistic one, which is called in this paper as moving spin. Further the concept of moving spin is discussed in the quantum field theory. A new is constructed. It is shown that, in virtue of the two operators, problems in quantum field concerned spin can be neatly settled.
Relativistic Guiding Center Equations
Energy Technology Data Exchange (ETDEWEB)
White, R. B. [PPPL; Gobbin, M. [Euratom-ENEA Association
2014-10-01
In toroidal fusion devices it is relatively easy that electrons achieve relativistic velocities, so to simulate runaway electrons and other high energy phenomena a nonrelativistic guiding center formalism is not sufficient. Relativistic guiding center equations including flute mode time dependent field perturbations are derived. The same variables as used in a previous nonrelativistic guiding center code are adopted, so that a straightforward modifications of those equations can produce a relativistic version.
Relativistic Linear Restoring Force
Clark, D.; Franklin, J.; Mann, N.
2012-01-01
We consider two different forms for a relativistic version of a linear restoring force. The pair comes from taking Hooke's law to be the force appearing on the right-hand side of the relativistic expressions: d"p"/d"t" or d"p"/d["tau"]. Either formulation recovers Hooke's law in the non-relativistic limit. In addition to these two forces, we…
Commercial compact cyclotrons in the 90`s
Energy Technology Data Exchange (ETDEWEB)
Milton, B.F.
1995-09-01
Cyclotrons continue to be efficient accelerators for radio-isotope production. In recent years, developments in the accelerator technology have greatly increased the practical beam current in these machines while also improving the overall system reliability. These developments combined with the development of new isotopes for medicine and industry, and a retiring of older machines indicate a strong future for commercial cyclotrons. In this paper the authors will survey recent developments in the areas of cyclotron technology, as they relate to the new generation of commercial cyclotrons. Design criteria for the different types of commercial cyclotrons will be presented, with reference to those demands that differ from those in a research oriented cyclotron project. The authors also discuss the possibility of systems designed for higher energies and capable of extracted beam currents of up to 2.0 mA.
Method and apparatus for ion cyclotron spectrometry
Dahl, David A [Idaho Falls, ID; Scott, Jill R [Idaho Falls, ID; McJunkin, Timothy R [Idaho Falls, ID
2010-08-17
An ion cyclotron spectrometer may include a vacuum chamber that extends at least along a z-axis and means for producing a magnetic field within the vacuum chamber so that a magnetic field vector is generally parallel to the z-axis. The ion cyclotron spectrometer may also include means for producing a trapping electric field within the vacuum chamber that includes at least a first section that induces a first magnetron effect that increases a cyclotron frequency of an ion and at least a second section that induces a second magnetron effect that decreases the cyclotron frequency of an ion. The cyclotron frequency changes induced by the first and second magnetron effects substantially cancel one another so that an ion traversing the at least first and second sections will experience no net change in cyclotron frequency.
MALFLIET, R
1993-01-01
We discuss the present status of relativistic transport theory. Special emphasis is put on problems of topical interest: hadronic features, thermodynamical consistent approximations and spectral properties.
Surprises in numerical expressions of physical constants
Amir, Ariel; Tokieda, Tadashi
2016-01-01
In science, as in life, `surprises' can be adequately appreciated only in the presence of a null model, what we expect a priori. In physics, theories sometimes express the values of dimensionless physical constants as combinations of mathematical constants like pi or e. The inverse problem also arises, whereby the measured value of a physical constant admits a `surprisingly' simple approximation in terms of well-known mathematical constants. Can we estimate the probability for this to be a mere coincidence, rather than an inkling of some theory? We answer the question in the most naive form.
Surprising Connections between Partitions and Divisors
Osler, Thomas J.; Hassen, Abdulkadir; Chandrupatla, Tirupathi R.
2007-01-01
The sum of the divisors of a positive integer is one of the most interesting concepts in multiplicative number theory, while the number of ways of expressing a number as a sum is a primary topic in additive number theory. In this article, we describe some of the surprising connections between and similarities of these two concepts.
Surprises from extragalactic propagation of UHECRs
Boncioli, Denise; Grillo, Aurelio
2015-01-01
Ultra-high energy cosmic ray experimental data are now of very good statistical significance even in the region of the expected GZK feature. The identification of their sources requires sophisticate analysis of their propagation in the extragalactic space. When looking at the details of this propagation some unforeseen features emerge. We will discuss some of these "surprises".
Relativistic quantum mechanics; Mecanique quantique relativiste
Energy Technology Data Exchange (ETDEWEB)
Ollitrault, J.Y. [CEA Saclay, 91 - Gif-sur-Yvette (France). Service de Physique Theorique]|[Universite Pierre et Marie Curie, 75 - Paris (France)
1998-12-01
These notes form an introduction to relativistic quantum mechanics. The mathematical formalism has been reduced to the minimum in order to enable the reader to calculate elementary physical processes. The second quantification and the field theory are the logical followings of this course. The reader is expected to know analytical mechanics (Lagrangian and Hamiltonian), non-relativistic quantum mechanics and some basis of restricted relativity. The purpose of the first 3 chapters is to define the quantum mechanics framework for already known notions about rotation transformations, wave propagation and restricted theory of relativity. The next 3 chapters are devoted to the application of relativistic quantum mechanics to a particle with 0,1/5 and 1 spin value. The last chapter deals with the processes involving several particles, these processes require field theory framework to be thoroughly described. (A.C.) 2 refs.
Mushtukov, Alexander A; Serber, Alexander V; Suleimanov, Valery F; Poutanen, Juri
2015-01-01
Cyclotron resonance scattering features observed in the spectra of some X-ray pulsars show significant changes of the line centroid energy with the pulsar luminosity. Whereas for bright sources above the so called critical luminosity these variations are established to be connected with the appearance of the high accretion column above the neutron star surface, at low, sub-critical luminosities the nature of the variations (but with the opposite sign) has not been discussed widely. We argue here that the cyclotron line is formed when the radiation from a hotspot propagates through the plasma falling with a mildly relativistic velocity onto the neutron star surface. The position of the cyclotron resonance is determined by the Doppler effect. The change of the cyclotron line position in the spectrum with luminosity is caused by variations of the velocity profile in the line-forming region affected by the radiation pressure force. The presented model has several characteristic features: (i) the line centroid ene...
Towards relativistic quantum geometry
Energy Technology Data Exchange (ETDEWEB)
Ridao, Luis Santiago [Instituto de Investigaciones Físicas de Mar del Plata (IFIMAR), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Mar del Plata (Argentina); Bellini, Mauricio, E-mail: mbellini@mdp.edu.ar [Departamento de Física, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Mar del Plata, Funes 3350, C.P. 7600, Mar del Plata (Argentina); Instituto de Investigaciones Físicas de Mar del Plata (IFIMAR), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Mar del Plata (Argentina)
2015-12-17
We obtain a gauge-invariant relativistic quantum geometry by using a Weylian-like manifold with a geometric scalar field which provides a gauge-invariant relativistic quantum theory in which the algebra of the Weylian-like field depends on observers. An example for a Reissner–Nordström black-hole is studied.
Cyclotron Line Measurements with INTEGRAL
Pottschmidt, K.; Kreykenbohm, I.; Caballero, I.; Fritz, S.; Schoenherr, G.; Kretschmar, P.; Wilms, J.; McBride, V. A.; Suchy, S.; Rothschild, R. E.
2008-01-01
Due to its broadband energy coverage, INTEGRAL has made important contributions to observing and interpreting cyclotron lines, which are present in the 10-100 keV range of a sample of accreting pulsars. In these systems photons with energies fulfilling the resonance condition inelastically Compton scatter off electrons quantized in the accretion column above the neutron star's magnetic pole(s). This process gives rise to the broad, absorption-like lines or 'cyclotron resonant scattering features' (CRSF). The observed lines allow to directly measure the B-fields of these sources, resulting in values of a few times 1E12G. In this overview I will present recent highlights regarding CRSF observations as well as discuss current ideas and models for the physical conditions in the accretion column. Among the former are the stability of the spectrum of Vela X-1 during giant flares in 2003, the observation of three cyclotron lines during the 2004 outburst of V0332+53, the confirmation of the fundamental line at approximately 45 keV during a 2005 normal outburst of A0535-26, and the simultaneous detection of the two lines in the dipping source 4U 1907+09 (for which also a torque reversal was detected for the first time). Through these and other observations it has become increasingly apparent that two types of observations can potentially be used to constrain the accretion column geometry: the determination of energy ratios for multiple harmonic lines (only two sources with greater than 2 lines are known), was well as the evolution of the fundamental line centroid, which, for different sources, may or may not be correlated with flux. Furthermore, first steps have been taken away from the usual phenomenological description of the lines, towards a physical approach based on self-consistent CRSF modeling. Initial applications are presented.
Russell, C. T.; Wei, H. Y.; Cowee, M. M.; Neubauer, F. M.; Dougherty, M. K.
2016-03-01
During the interaction of Titan's thick atmosphere with the ambient plasma, it was expected that ion cyclotron waves would be generated by the free energy of the highly anisotropic velocity distribution of the freshly ionized atmospheric particles created in the interaction. However, ion cyclotron waves are rarely observed near Titan, due to the long growth times of waves associated with the major ion species from Titan's ionosphere, such as CH4+ and N2+. In the over 100 Titan flybys obtained by Cassini to date, there are only two wave events, for just a few minutes during T63 flyby and for tens of minutes during T98 flyby. These waves occur near the gyrofrequencies of proton and singly ionized molecular hydrogen. They are left-handed, elliptically polarized, and propagate nearly parallel to the field lines. Hybrid simulations are performed to understand the wave growth under various conditions in the Titan environment. The simulations using the plasma and field conditions during T63 show that pickup protons with densities ranging from 0.01 cm-3 to 0.02 cm-3 and singly ionized molecular hydrogens with densities ranging from 0.015 cm-3 to 0.25 cm-3 can drive ion cyclotron waves with amplitudes of ~0.02 nT and of ~0.04 nT within appropriate growth times at Titan, respectively. Since the T98 waves were seen farther upstream than the T63 waves, it is possible that the instability was stronger and grew faster on T98 than T63.
Cyclotron Line Measurements with INTEGRAL
Pottschmidt, K.; Kreykenbohm, I.; Caballero, I.; Fritz, S.; Schoenherr, G.; Kretschmar, P.; Wilms, J.; McBride, V. A.; Suchy, S.; Rothschild, R. E.
2008-01-01
Due to its broadband energy coverage, INTEGRAL has made important contributions to observing and interpreting cyclotron lines, which are present in the 10-100 keV range of a sample of accreting pulsars. In these systems photons with energies fulfilling the resonance condition inelastically Compton scatter off electrons quantized in the accretion column above the neutron star's magnetic pole(s). This process gives rise to the broad, absorption-like lines or 'cyclotron resonant scattering features' (CRSF). The observed lines allow to directly measure the B-fields of these sources, resulting in values of a few times 1E12G. In this overview I will present recent highlights regarding CRSF observations as well as discuss current ideas and models for the physical conditions in the accretion column. Among the former are the stability of the spectrum of Vela X-1 during giant flares in 2003, the observation of three cyclotron lines during the 2004 outburst of V0332+53, the confirmation of the fundamental line at approximately 45 keV during a 2005 normal outburst of A0535-26, and the simultaneous detection of the two lines in the dipping source 4U 1907+09 (for which also a torque reversal was detected for the first time). Through these and other observations it has become increasingly apparent that two types of observations can potentially be used to constrain the accretion column geometry: the determination of energy ratios for multiple harmonic lines (only two sources with greater than 2 lines are known), was well as the evolution of the fundamental line centroid, which, for different sources, may or may not be correlated with flux. Furthermore, first steps have been taken away from the usual phenomenological description of the lines, towards a physical approach based on self-consistent CRSF modeling. Initial applications are presented.
Choinski, J.; Miszczak, J.; Sura, J.
2001-12-01
The overview of the Warsaw cyclotron facility is presented. The facility consists of K=160 cyclotron, 10 GHz ECR ion source, and several experimental stations. The cyclotron is of compact design with 2 straight dees. A yearly operation time is about 2900 hours on an average for the past few years. The cyclotron can deliver beams up to Ar with energy up to 10 MeV/amu to the experimental area. Experimental stations are: 1) The multidetector OSIRIS II, allows the study of exotic nuclei in the double magic 100Sn region. The experimental set-up consists of 8 HPGe detectors equipped with charged particle 4π multiplicity filter SiBall, 50 elements BGO γ-rays multiplicity filter, 4 sector polarimeter and electron conversion detector system. 2) CUDAC-Coulomb Universal Detector Scattering Chamber-an array of PIN-diodes in connection with HPGe detectors and the computer data analysis package GOSIA, maintained by the Laboratory allows investigation the Coulomb Excitation (COULEX) reactions. 3) IGISOL or Helium-jet transport system opened investigation of the reaction products by means of the online mass separator with ion-guide system. The system uses the Scandinavian-type mass separator built in INR Świerk, Poland. 4) Giant Dipole Resonance studies using experimental set-up JANOSIK developed for the detection of high-energy photons emitted in heavy-ion collisions. The set-up consists of a large NaI(Tl) detector (25 cm×29 cm) surrounded by shields: passive lead shield, active anticoincidence plastic shield and LiH shield to absorb neutrons, and a multiplicity filter of 32 small scintillator detectors (BaF2 and NaI(Tl)). 5) Laser spectroscopy stand now in test phase. The laser spectroscopy group at HIL has completed an equipment consisting of Argon ion Laser Innova 400-25W in all lines and coherent Ring Laser 669-21 as well as atomic beam apparatus.
Superconducting cyclotrons at Michigan State University
Blosser, H. G.
1987-04-01
This paper describes the status of the three superconducting cyclotrons which are in operation or under construction at the National Superconducting Cyclotron Laboratory. The oldest of these, the K500, has been in operation since September 1982 supporting a national user program in heavy ion nuclear physics. A second large research cyclotron, the K800, is now nearing completion. This cyclotron will accelerate lighter heavy ions to 200 MeV/nuc and heavier particles up to energies given by 1200 Q2/ A MeV/nucleon. The magnet for this cyclotron came into operation in May 1984 and has performed smoothly and reliably in three extended operating periods. At present, K800 construction activity centers on fabrication and installation of the rf system, the extraction system, and the ECR injection line. The third NSCL superconducting cyclotron is a smaller 50 MeV deuteron cyclotron to be used for neutron therapy in the radiation oncology center of a major Detroit hospital (Harper Hospital). Design features of this small, application oriented, cyclotron are described in some detail.
Radar Design to Protect Against Surprise
Energy Technology Data Exchange (ETDEWEB)
Doerry, Armin W. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
2015-02-01
Technological and doctrinal surprise is about rendering preparations for conflict as irrelevant or ineffective . For a sensor, this means essentially rendering the sensor as irrelevant or ineffective in its ability to help determine truth. Recovery from this sort of surprise is facilitated by flexibility in our own technology and doctrine. For a sensor, this mean s flexibility in its architecture, design, tactics, and the designing organizations ' processes. - 4 - Acknowledgements This report is the result of a n unfunded research and development activity . Sandia National Laboratories is a multi - program laboratory manage d and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE - AC04 - 94AL85000.
Surprise Leads to Noisier Perceptual Decisions
Directory of Open Access Journals (Sweden)
Marta I Garrido
2011-02-01
Full Text Available Surprising events in the environment can impair task performance. This might be due to complete distraction, leading to lapses during which performance is reduced to guessing. Alternatively, unpredictability might cause a graded withdrawal of perceptual resources from the task at hand and thereby reduce sensitivity. Here we attempt to distinguish between these two mechanisms. Listeners performed a novel auditory pitch—duration discrimination, where stimulus loudness changed occasionally and incidentally to the task. Responses were slower and less accurate in the surprising condition, where loudness changed unpredictably, than in the predictable condition, where the loudness was held constant. By explicitly modelling both lapses and changes in sensitivity, we found that unpredictable changes diminished sensitivity but did not increase the rate of lapses. These findings suggest that background environmental uncertainty can disrupt goal-directed behaviour. This graded processing strategy might be adaptive in potentially threatening contexts, and reflect a flexible system for automatic allocation of perceptual resources.
Radar Design to Protect Against Surprise.
Energy Technology Data Exchange (ETDEWEB)
Doerry, Armin W.
2015-02-01
Technological and doctrinal surprise is about rendering preparations for conflict as irrelevant or ineffective . For a sensor, this means essentially rendering the sensor as irrelevant or ineffective in its ability to help determine truth. Recovery from this sort of surprise is facilitated by flexibility in our own technology and doctrine. For a sensor, this mean s flexibility in its architecture, design, tactics, and the designing organizations ' processes. - 4 - Acknowledgements This report is the result of a n unfunded research and development activity . Sandia National Laboratories is a multi - program laboratory manage d and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE - AC04 - 94AL85000.
Relativistic and Non-relativistic Equations of Motion
Mangiarotti, L
1998-01-01
It is shown that any second order dynamic equation on a configuration space $X$ of non-relativistic time-dependent mechanics can be seen as a geodesic equation with respect to some (non-linear) connection on the tangent bundle $TX\\to X$ of relativistic velocities. Using this fact, the relationship between relativistic and non-relativistic equations of motion is studied.
Surprise-Based Learning for Autonomous Systems
2009-02-28
for scientific theories containing recursive theoretical terms". British Journal of Philosophy of Science, 44. 641-652, 1993. Piaget J.. "The Origins...paradigm stems from Piaget’s theory of Developmental Psychology [5], Herben Simon’s theory on dual-space search for knowledge and problem solving [6...34, Twenty-First Conference on Uncertainty in Artificial Intelligence, Edinburgh, Scotland, July 2005. [34] Itti L., Baldi P., "A Surprising Theory of
Developing the smallest possible medical cyclotron
Katarina Anthony
2011-01-01
Imagine a portable medical cyclotron operated in a conventional radioactive facility at a hospital. Imagine a nurse or technician switching it on and producing isotopes at the patient’s bedside. Sounds like science fiction? Think again. CERN has teamed up with Spain’s national scientific research centre (CIEMAT) to develop an avant-garde cyclotron to be used for Positron Emission Tomography (PET). “We plan to make a cyclotron that doesn't need an insulated building or ‘vault’: a cyclotron small enough to fit inside a hospital lift,” explains Jose Manuel Perez, who is leading the CIEMAT/CERN collaboration. “It will be the smallest possible medical cyclotron for single patient dose production and will dramatically reduce costs for hospitals.” While PET technology has transformed imaging techniques, many of its medical benefits have remained confined to highly specialised hospitals. “Studies have foun...
Relativistic effects in homogeneous gold catalysis.
Gorin, David J; Toste, F Dean
2007-03-22
Transition-metal catalysts containing gold present new opportunities for chemical synthesis, and it is therefore not surprising that these complexes are beginning to capture the attention of the chemical community. Cationic phosphine-gold(i) complexes are especially versatile and selective catalysts for a growing number of synthetic transformations. The reactivity of these species can be understood in the context of theoretical studies on gold; relativistic effects are especially helpful in rationalizing the reaction manifolds available to gold catalysts. This Review draws on experimental and computational data to present our current understanding of homogeneous gold catalysis, focusing on previously unexplored reactivity and its application to the development of new methodology.
Highly charged ion X-rays from Electron-Cyclotron Resonance Ion Sources
Indelicato, Paul; Boucard, S.; Covita, D. S.; Gotta, D.; Gruber, A; Hirtl, A.; Fuhrmann, H.; Le Bigot, E.-O.; Schlesser, S.; dos Santos, J. M. F.; Simons, L.M.; Stingelin, L.; Trassinelli, Martino; Veloso, J.; Wasser, A.
2006-01-01
Radiation from the highly-charged ions contained in the plasma of Electron-Cyclotron Resonance Ion Sources constitutes a very bright source of X-rays. Because the ions have a relatively low kinetic energy ($\\approx 1$~eV) transitions can be very narrow, containing only small Doppler broadening. We describe preliminary accurate measurements of two and three-electron ions with $Z=16$--18. We show how these measurement can test sensitively many-body relativistic calculations or can be used as X-...
Pupil size tracks perceptual content and surprise.
Kloosterman, Niels A; Meindertsma, Thomas; van Loon, Anouk M; Lamme, Victor A F; Bonneh, Yoram S; Donner, Tobias H
2015-04-01
Changes in pupil size at constant light levels reflect the activity of neuromodulatory brainstem centers that control global brain state. These endogenously driven pupil dynamics can be synchronized with cognitive acts. For example, the pupil dilates during the spontaneous switches of perception of a constant sensory input in bistable perceptual illusions. It is unknown whether this pupil dilation only indicates the occurrence of perceptual switches, or also their content. Here, we measured pupil diameter in human subjects reporting the subjective disappearance and re-appearance of a physically constant visual target surrounded by a moving pattern ('motion-induced blindness' illusion). We show that the pupil dilates during the perceptual switches in the illusion and a stimulus-evoked 'replay' of that illusion. Critically, the switch-related pupil dilation encodes perceptual content, with larger amplitude for disappearance than re-appearance. This difference in pupil response amplitude enables prediction of the type of report (disappearance vs. re-appearance) on individual switches (receiver-operating characteristic: 61%). The amplitude difference is independent of the relative durations of target-visible and target-invisible intervals and subjects' overt behavioral report of the perceptual switches. Further, we show that pupil dilation during the replay also scales with the level of surprise about the timing of switches, but there is no evidence for an interaction between the effects of surprise and perceptual content on the pupil response. Taken together, our results suggest that pupil-linked brain systems track both the content of, and surprise about, perceptual events.
Relativistic spherical plasma waves
Bulanov, S. S.; Maksimchuk, A.; Schroeder, C. B.; Zhidkov, A. G.; Esarey, E.; Leemans, W. P.
2012-02-01
Tightly focused laser pulses that diverge or converge in underdense plasma can generate wake waves, having local structures that are spherical waves. Here we study theoretically and numerically relativistic spherical wake waves and their properties, including wave breaking.
Relativistic GLONASS and geodesy
Mazurova, E. M.; Kopeikin, S. M.; Karpik, A. P.
2016-12-01
GNSS technology is playing a major role in applications to civil, industrial and scientific areas. Nowadays, there are two fully functional GNSS: American GPS and Russian GLONASS. Their data processing algorithms have been historically based on the Newtonian theory of space and time with only a few relativistic effects taken into account as small corrections preventing the system from degradation on a fairly long time. Continuously growing accuracy of geodetic measurements and atomic clocks suggests reconsidering the overall approach to the GNSS theoretical model based on the Einstein theory of general relativity. This is essentially more challenging but fundamentally consistent theoretical approach to relativistic space geodesy. In this paper, we overview the basic principles of the relativistic GNSS model and explain the advantages of such a system for GLONASS and other positioning systems. Keywords: relativistic GLONASS, Einstein theory of general relativity.
Bliokh, Konstantin Y
2011-01-01
We consider the relativistic deformation of quantum waves and mechanical bodies carrying intrinsic angular momentum (AM). When observed in a moving reference frame, the centroid of the object undergoes an AM-dependent transverse shift. This is the relativistic analogue of the spin Hall effect, which occurs in free space without any external fields. Remarkably, the shifts of the geometric and energy centroids differ by a factor of 2, and both centroids are crucial for the correct Lorentz transformations of the AM tensor. We examine manifestations of the relativistic Hall effect in quantum vortices, mechanical flywheel, and discuss various fundamental aspects of the phenomenon. The perfect agreement of quantum and relativistic approaches allows applications at strikingly different scales: from elementary spinning particles, through classical light, to rotating black-holes.
Exact Relativistic 'Antigravity' Propulsion
Felber, F S
2006-01-01
The Schwarzschild solution is used to find the exact relativistic motion of a payload in the gravitational field of a mass moving with constant velocity. At radial approach or recession speeds faster than 3^-1/2 times the speed of light, even a small mass gravitationally repels a payload. At relativistic speeds, a suitable mass can quickly propel a heavy payload from rest nearly to the speed of light with negligible stresses on the payload.
Exact Relativistic `Antigravity' Propulsion
Felber, Franklin S.
2006-01-01
The Schwarzschild solution is used to find the exact relativistic motion of a payload in the gravitational field of a mass moving with constant velocity. At radial approach or recession speeds faster than 3-1/2 times the speed of light, even a small mass gravitationally repels a payload. At relativistic speeds, a suitable mass can quickly propel a heavy payload from rest nearly to the speed of light with negligible stresses on the payload.
Relativistic quantum revivals.
Strange, P
2010-03-26
Quantum revivals are now a well-known phenomena within nonrelativistic quantum theory. In this Letter we display the effects of relativity on revivals and quantum carpets. It is generally believed that revivals do not occur within a relativistic regime. Here we show that while this is generally true, it is possible, in principle, to set up wave packets with specific mathematical properties that do exhibit exact revivals within a fully relativistic theory.
Injection and extraction for cyclotrons
Kleeven, W
2006-01-01
The main design goals for beam injection are explained and special problems related to a central region with internal ion source are considered. The principle of a PIG source is addressed. The issue of vertical focusing in the cyclotron centre is briefly discussed. Several examples of numerical simulations are given. Different ways of (axial) injection are briefly outlined. A proposal for a magnetostatic axial inflector is given. Different solutions for beam extraction are treated. These include the internal target, extraction by stripping, resonant extraction using a deflector and self-extraction. The different ways of creating a turn-separation are explained. The purpose of different types of extraction devices such as harmonic coils, deflectors and gradient corrector channels are outlined. Several illustrations are given in the form of photographs and drawings.
Relativistic viscoelastic fluid mechanics.
Fukuma, Masafumi; Sakatani, Yuho
2011-08-01
A detailed study is carried out for the relativistic theory of viscoelasticity which was recently constructed on the basis of Onsager's linear nonequilibrium thermodynamics. After rederiving the theory using a local argument with the entropy current, we show that this theory universally reduces to the standard relativistic Navier-Stokes fluid mechanics in the long time limit. Since effects of elasticity are taken into account, the dynamics at short time scales is modified from that given by the Navier-Stokes equations, so that acausal problems intrinsic to relativistic Navier-Stokes fluids are significantly remedied. We in particular show that the wave equations for the propagation of disturbance around a hydrostatic equilibrium in Minkowski space-time become symmetric hyperbolic for some range of parameters, so that the model is free of acausality problems. This observation suggests that the relativistic viscoelastic model with such parameters can be regarded as a causal completion of relativistic Navier-Stokes fluid mechanics. By adjusting parameters to various values, this theory can treat a wide variety of materials including elastic materials, Maxwell materials, Kelvin-Voigt materials, and (a nonlinearly generalized version of) simplified Israel-Stewart fluids, and thus we expect the theory to be the most universal description of single-component relativistic continuum materials. We also show that the presence of strains and the corresponding change in temperature are naturally unified through the Tolman law in a generally covariant description of continuum mechanics.
Cyclotron resonance absorption in ionospheric plasma
Villalon, Elena
1991-04-01
The mode conversion of ordinary polarized electromagnetic waves into electrostatic cyclotron waves in the inhomogeneous ionospheric plasma is investigated. Near resonance the warm plasma dispersion relation is a function of the angle theta between the geomagnetic field and the density gradient and of the wave frequency omega, which lies between the electron cyclotron frequency and its doubling. The differential equations describing the electric field amplitudes near the plasma resonance are studied, including damping at the second gyroharmonic. The energy transmission coefficients and power absorbed by the cyclotron waves are calculated. The vertical penetration of the plasma wave amplitudes is estimated using a WKB analysis of the wave equation.
Cyclotron Line Features from Near-Critical Fields II on the Effect of Anisotropic Radiation Fields
Araya-Gochez, R A; Araya-Gochez, Rafael A.; Harding, Alice K.
2000-01-01
We assess the impact of radiation anisotropy on the line shapes that result from relativistic magnetic Compton scattering in the low-density/high-field regime. A Monte Carlo implementation of radiation transport allows for spatial diffusion of photons in arbitrary geometries and accounts for relativistic angular redistribution. The cross section includes natural line widths and photon "spawning" from up to fourth harmonic photons. In our first paper we noted that even if the photon injection is isotropic a strongly anisotropic radiation field rapidly ensues. We now investigate the angular distribution of cyclotron spectra emerging from an internally irradiated magnetized plasma with a prescribed global geometry (either cylindrical or plane parallel) and the effects of anisotropic photon injection on the line shapes. Varying the input angular distribution permits a better understanding of the line formation process in more realistic scenarios where the radiative mechanisms are influenced by the intrinsic aniso...
Mayo, D
2014-03-01
A common intuition about evidence is that if data x have been used to construct a hypothesis H, then x should not be used again in support of H. It is no surprise that x fits H, if H was deliberately constructed to accord with x. The question of when and why we should avoid such "double-counting" continues to be debated in philosophy and statistics. It arises as a prohibition against data mining, hunting for significance, tuning on the signal, and ad hoc hypotheses, and as a preference for predesignated hypotheses and "surprising" predictions. I have argued that it is the severity or probativeness of the test--or lack of it--that should determine whether a double-use of data is admissible. I examine a number of surprising ambiguities and unexpected facts that continue to bedevil this debate.
Electron cyclotron heating and current drive
Westerhof, E.
1996-01-01
Plasma heating and non-inductive current drive by waves in the electron cyclotron range of frequencies are reviewed. Both theoretical aspects concerning wave properties, heating and current drive mechanisms, as well as the major experimental results are summarized.
Method and apparatuses for ion cyclotron spectrometry
Dahl, David A [Idaho Falls, ID; Scott, Jill R [Idaho Falls, ID; McJunkin, Timothy R [Idaho Falls, ID
2012-03-06
An ion cyclotron spectrometer may include a vacuum chamber that extends at least along a z-axis and means for producing a magnetic field within the vacuum chamber so that a magnetic field vector is generally parallel to the z-axis. The ion cyclotron spectrometer may also include means for producing a trapping electric field within the vacuum chamber. The trapping electric field may comprise a field potential that, when taken in cross-section along the z-axis, includes at least one section that is concave down and at least one section that is concave up so that ions traversing the field potential experience a net magnetron effect on a cyclotron frequency of the ions that is substantially equal to zero. Other apparatuses and a method for performing ion cyclotron spectrometry are also disclosed herein.
Stroke Recovery: Surprising Influences and Residual Consequences
Directory of Open Access Journals (Sweden)
Argye E. Hillis
2014-01-01
Full Text Available There is startling individual variability in the degree to which people recover from stroke and the duration of time over which recovery of some symptoms occurs. There are a variety of mechanisms of recovery from stroke which take place at distinct time points after stroke and are influenced by different variables. We review recent studies from our laboratory that unveil some surprising findings, such as the role of education in chronic recovery. We also report data showing that the consequences that most plague survivors of stroke and their caregivers are loss of high level cortical functions, such as empathy or written language. These results have implications for rehabilitation and management of stroke.
Surprises and mysteries in urban soils
Groffman, P. M.
2015-12-01
In the Baltimore Ecosystem Study, one of two urban long-term ecological research (LTER) projects funded by the U.S. National Science Foundation, we are using "the watershed approach" to integrate ecological, physical and social sciences. Urban and suburban watershed input/output budgets for nitrogen have shown surprisingly high retention which has led to detailed analysis of sources and sinks in soils these watersheds. Home lawns, thought to be major sources of reactive nitrogen in suburban watersheds, have more complex coupled carbon and nitrogen dynamics than previously thought, and are likely the site of much nitrogen retention. Riparian zones, thought to be an important sink for reactive nitrogen in many watersheds, have turned out be nitrogen sources in urban watersheds due to hydrologic changes that disconnect streams from their surrounding landscape. Urban effects on atmospheric carbon dioxide levels and nitrogen deposition have strong effects on soil nitrogen cycling processes and soil:atmosphere fluxes of nitrous oxide, carbon dioxide and methane. Efforts to manage urban soils and watersheds through geomorphic stream restoration, creation of stormwater management features and changes in lawn and forest management can have significant effects on watershed carbon and nitrogen dynamics. Urban soils present a basic and applied science frontier that challenges our understanding of biological, physical, chemical and social science processes. The watershed approach provides an effective platform for integrating these disciplines and for articulating critical questions that arise from surprising results. This approach can help us to meet the challenge of urban soils, which is critical to achieving sustainability goals in cities across the world.
Shielding Design for a Medical Cyclotron
Institute of Scientific and Technical Information of China (English)
WANG; Feng; SONG; Guo-fang; GUAN; Feng-ping; LV; Yin-long; ZHANG; Xing-zhi
2012-01-01
<正>A 10 MeV 100 μA medical cyclotron is constructed at CIAE which is used in the production of FDG. The energy of the cyclotron can reach 14 MeV by adjusting the magnetic field and RF system parameters, and the shielding design is in accordance with the 14 MeV beam energy. In this shielding design only neutron is considered, and the neutron source is produced by proton
Building 211 cyclotron characterization survey report
Energy Technology Data Exchange (ETDEWEB)
NONE
1998-03-30
The Building 211 Cyclotron Characterization Survey includes an assessment of the radioactive and chemical inventory of materials stored within the facility; an evaluation of the relative distribution of accelerator-produced activation products within various cyclotron components and adjacent structures; measurement of the radiation fields throughout the facility; measurement and assessment of internal and external radioactive surface contamination on various equipment, facility structures, and air-handling systems; and an assessment of lead (Pb) paint and asbestos hazards within the facility.
Precipitation of relativistic electrons of the Van Allen belts into the proton aurora
Energy Technology Data Exchange (ETDEWEB)
Jordanova, Vania K [Los Alamos National Laboratory; Miyoshi, Y [NAGOYA UNIV; Sakaguchi, K [NAGOYA UNIV; Shiokawa, K [NAGOYA UNIV; Evans, D S [SEC/NOAA; Albert, Jay [AFRL; Connors, M [UNIV OF ATHABASCA
2008-01-01
The Van Allen electron belts consist of two regions encircling the earth in which relativistic electrons are trapped in the earth's magnetic field. Populations of relativistic electrons in the Van Allen belts vary greatly with geomagnetic disturbance and they are a major source of damage to space vehicles. In order to know when and by how much these populations of relativistic electrons increase, it is important to elucidate not only the cause of acceleration of relativistic electrons but also the cause of their loss from the Van Allen belts. Here we show the first evidence that left-hand polarized electromagnetic ion cyclotron (EMIC) plasma waves can cause the loss of relativistic electrons into the atmosphere, on the basis of results of an excellent set of ground and satellite observations showing coincident precipitation of ions with energies of tens of keV and of relativistic electrons into an isolated proton aurora. The proton aurora was produced by precipitation of ions with energies of tens of keV due to EMIC waves near the plasma pause, which is a manifestation of wave-particle interactions. These observations clarify that ions with energies of tens of keV affect the evolution of relativistic electrons in the Van Allen belts via parasitic resonance with EMIC waves, an effect that was first theoretically predicted in the early 1970's.
The conceptualization model problem—surprise
Bredehoeft, John
2005-03-01
The foundation of model analysis is the conceptual model. Surprise is defined as new data that renders the prevailing conceptual model invalid; as defined here it represents a paradigm shift. Limited empirical data indicate that surprises occur in 20-30% of model analyses. These data suggest that groundwater analysts have difficulty selecting the appropriate conceptual model. There is no ready remedy to the conceptual model problem other than (1) to collect as much data as is feasible, using all applicable methods—a complementary data collection methodology can lead to new information that changes the prevailing conceptual model, and (2) for the analyst to remain open to the fact that the conceptual model can change dramatically as more information is collected. In the final analysis, the hydrogeologist makes a subjective decision on the appropriate conceptual model. The conceptualization problem does not render models unusable. The problem introduces an uncertainty that often is not widely recognized. Conceptual model uncertainty is exacerbated in making long-term predictions of system performance. C'est le modèle conceptuel qui se trouve à base d'une analyse sur un modèle. On considère comme une surprise lorsque le modèle est invalidé par des données nouvelles; dans les termes définis ici la surprise est équivalente à un change de paradigme. Des données empiriques limitées indiquent que les surprises apparaissent dans 20 à 30% des analyses effectuées sur les modèles. Ces données suggèrent que l'analyse des eaux souterraines présente des difficultés lorsqu'il s'agit de choisir le modèle conceptuel approprié. Il n'existe pas un autre remède au problème du modèle conceptuel que: (1) rassembler autant des données que possible en utilisant toutes les méthodes applicables—la méthode des données complémentaires peut conduire aux nouvelles informations qui vont changer le modèle conceptuel, et (2) l'analyste doit rester ouvert au fait
Indian Academy of Sciences (India)
Arpita Ghosh; Somenath Chakrabarty
2011-09-01
Following an extremely interesting idea (Schieber 1984), published long ago, the work function associated with the emission of ultra-relativistic electrons from magnetically deformed metallic crystal (mainly iron) at the outer crust of a magnetar is obtained using relativistic version of Thomas–Fermi type model for electron distribution around the nuclei in this region. In the present scenario, surprisingly, the work function becomes anisotropic; the longitudinal part is an increasing function of magnetic field strength, whereas the transverse part diverges.
Relativistic theories of materials
Bressan, Aldo
1978-01-01
The theory of relativity was created in 1905 to solve a problem concerning electromagnetic fields. That solution was reached by means of profound changes in fundamental concepts and ideas that considerably affected the whole of physics. Moreover, when Einstein took gravitation into account, he was forced to develop radical changes also in our space-time concepts (1916). Relativistic works on heat, thermodynamics, and elasticity appeared as early as 1911. However, general theories having a thermodynamic basis, including heat conduction and constitutive equations, did not appear in general relativity until about 1955 for fluids and appeared only after 1960 for elastic or more general finitely deformed materials. These theories dealt with materials with memory, and in this connection some relativistic versions of the principle of material indifference were considered. Even more recently, relativistic theories incorporating finite deformations for polarizable and magnetizable materials and those in which couple s...
Relativistic Quantum Communication
Hosler, Dominic
2013-01-01
In this Ph.D. thesis, I investigate the communication abilities of non-inertial observers and the precision to which they can measure parametrized states. I introduce relativistic quantum field theory with field quantisation, and the definition and transformations of mode functions in Minkowski, Schwarzschild and Rindler spaces. I introduce information theory by discussing the nature of information, defining the entropic information measures, and highlighting the differences between classical and quantum information. I review the field of relativistic quantum information. We investigate the communication abilities of an inertial observer to a relativistic observer hovering above a Schwarzschild black hole, using the Rindler approximation. We compare both classical communication and quantum entanglement generation of the state merging protocol, for both the single and dual rail encodings. We find that while classical communication remains finite right up to the horizon, the quantum entanglement generation tend...
Relativistic quantum mechanics
Horwitz, Lawrence P
2015-01-01
This book describes a relativistic quantum theory developed by the author starting from the E.C.G. Stueckelberg approach proposed in the early 40s. In this framework a universal invariant evolution parameter (corresponding to the time originally postulated by Newton) is introduced to describe dynamical evolution. This theory is able to provide solutions for some of the fundamental problems encountered in early attempts to construct a relativistic quantum theory. A relativistically covariant construction is given for which particle spins and angular momenta can be combined through the usual rotation group Clebsch-Gordan coefficients. Solutions are defined for both the classical and quantum two body bound state and scattering problems. The recently developed quantum Lax-Phillips theory of semigroup evolution of resonant states is described. The experiment of Lindner and coworkers on interference in time is discussed showing how the property of coherence in time provides a simple understanding of the results. Th...
Acceleration and loss of relativistic electrons during small geomagnetic storms.
Anderson, B R; Millan, R M; Reeves, G D; Friedel, R H W
2015-12-16
Past studies of radiation belt relativistic electrons have favored active storm time periods, while the effects of small geomagnetic storms (Dst > -50 nT) have not been statistically characterized. In this timely study, given the current weak solar cycle, we identify 342 small storms from 1989 through 2000 and quantify the corresponding change in relativistic electron flux at geosynchronous orbit. Surprisingly, small storms can be equally as effective as large storms at enhancing and depleting fluxes. Slight differences exist, as small storms are 10% less likely to result in flux enhancement and 10% more likely to result in flux depletion than large storms. Nevertheless, it is clear that neither acceleration nor loss mechanisms scale with storm drivers as would be expected. Small geomagnetic storms play a significant role in radiation belt relativistic electron dynamics and provide opportunities to gain new insights into the complex balance of acceleration and loss processes.
Super revivals of a slightly relativistic particle in a box
Ghosh, Suranjana
2010-01-01
The time evolution of a particle, caught in an infinitely deep square well, is an apparently well studied and understood subject. However, unexpected features emerge, when one includes small relativistic effects. Indeed, even the smallest corrections to the nonrelativistic quadratic spectrum manifest themselves in a dramatic way. Our theoretical analysis brings to light a completely new time scale, at which the system exhibits surprisingly perfect revivals. This longer time scale rules the system dynamics and replaces the original revival time of the unperturbed system. We investigate the role and the interplay between these two time scales in the slightly relativistic case. Moreover, the examination of sub-Planck structures in phase space allows us to compare the finest details of wave packet dynamics for different values of the relativistic corrections.
Handbook of relativistic quantum chemistry
Energy Technology Data Exchange (ETDEWEB)
Liu, Wenjian (ed.) [Peking Univ., Beijing (China). Center for Computational Science and Engineering
2017-03-01
This handbook focuses on the foundations of relativistic quantum mechanics and addresses a number of fundamental issues never covered before in a book. For instance: How can many-body theory be combined with quantum electrodynamics? How can quantum electrodynamics be interfaced with relativistic quantum chemistry? What is the most appropriate relativistic many-electron Hamiltonian? How can we achieve relativistic explicit correlation? How can we formulate relativistic properties? - just to name a few. Since relativistic quantum chemistry is an integral component of computational chemistry, this handbook also supplements the ''Handbook of Computational Chemistry''. Generally speaking, it aims to establish the 'big picture' of relativistic molecular quantum mechanics as the union of quantum electrodynamics and relativistic quantum chemistry. Accordingly, it provides an accessible introduction for readers new to the field, presents advanced methodologies for experts, and discusses possible future perspectives, helping readers understand when/how to apply/develop the methodologies.
Relativistic electronic dressing
Attaourti, Y
2002-01-01
We study the effects of the relativistic electronic dressing in laser-assisted electron-hydrogen atom elastic collisions. We begin by considering the case when no radiation is present. This is necessary in order to check the consistency of our calculations and we then carry out the calculations using the relativistic Dirac-Volkov states. It turns out that a simple formal analogy links the analytical expressions of the differential cross section without laser and the differential cross section in presence of a laser field.
Fabian, A C; Parker, M L
2014-01-01
Broad emission lines, particularly broad iron-K lines, are now commonly seen in the X-ray spectra of luminous AGN and Galactic black hole binaries. Sensitive NuSTAR spectra over the energy range of 3-78 keV and high frequency reverberation spectra now confirm that these are relativistic disc lines produced by coronal irradiation of the innermost accretion flow around rapidly spinning black holes. General relativistic effects are essential in explaining the observations. Recent results are briefly reviewed here.
Relativistic Rotating Vector Model
Lyutikov, Maxim
2016-01-01
The direction of polarization produced by a moving source rotates with the respect to the rest frame. We show that this effect, induced by pulsar rotation, leads to an important correction to polarization swings within the framework of rotating vector model (RVM); this effect has been missed by previous works. We construct relativistic RVM taking into account finite heights of the emission region that lead to aberration, time-of-travel effects and relativistic rotation of polarization. Polarizations swings at different frequencies can be used, within the assumption of the radius-to-frequency mapping, to infer emission radii and geometry of pulsars.
The special relativistic shock tube
Thompson, Kevin W.
1986-01-01
The shock-tube problem has served as a popular test for numerical hydrodynamics codes. The development of relativistic hydrodynamics codes has created a need for a similar test problem in relativistic hydrodynamics. The analytical solution to the special relativistic shock-tube problem is presented here. The relativistic shock-jump conditions and rarefaction solution which make up the shock tube are derived. The Newtonian limit of the calculations is given throughout.
Mansfeld, Dmitry; Viktorov, Mikhail; Golubev, Sergey; Vodopyanov, Alexander
Despite more than half a century history, the studies of the interaction between electromagnetic waves and particles in magnetoactive plasma under electron cyclotron resonance (ECR) conditions still remain topical. One of the most interesting ECR manifestations is the generation of bursts of electromagnetic radiation that are related to the explosive growth of cyclotron instabilities of the magnetoactive plasma confined in magnetic traps of various kinds and that are accompanied by particle precipitations from the trap. Such phenomena are observed in a wide range of plasma parameters under various conditions: in the magnetospheres of the Earth and planets, in solar coronal loops, and in laboratory magnetic traps. We demonstrate the use of a laboratory setup based on a magnetic mirror trap with plasma sustained by a gyrotron radiation under ECR conditions for investigation of the cyclotron instabilities similar to the ones which take place in space plasmas. Three stages of pulsed ECR discharge offer the opportunity to study wave-particles interactions for essentially different plasma parameters: the initial stage, when the density of hot (relativistic) electrons (Nh) exceeds the density of cold electrons (Nc), the developed discharge (NhZ- or X- mode), propagating across the external magnetic field. The detailed investigation of spectral and temporal characteristics of non-stationary bursts of electromagnetic emission is presented. The interrelationship between the observed time-frequency spectrograms of electromagnetic emission with similar effects occurring in the inner magnetosphere is discussed in report.
Surprising characteristics of visual systems of invertebrates.
González-Martín-Moro, J; Hernández-Verdejo, J L; Jiménez-Gahete, A E
2017-01-01
To communicate relevant and striking aspects about the visual system of some close invertebrates. Review of the related literature. The capacity of snails to regenerate a complete eye, the benefit of the oval shape of the compound eye of many flying insects as a way of stabilising the image during flight, the potential advantages related to the extreme refractive error that characterises the ocelli of many insects, as well as the ability to detect polarised light as a navigation system, are some of the surprising capabilities present in the small invertebrate eyes that are described in this work. The invertebrate eyes have capabilities and sensorial modalities that are not present in the human eye. The study of the eyes of these animals can help us to improve our understanding of our visual system, and inspire the development of optical devices. Copyright © 2016 Sociedad Española de Oftalmología. Publicado por Elsevier España, S.L.U. All rights reserved.
Surprises from Saturn: Implications for Other Environments
Coates, A. J.
2014-05-01
The exploration of Saturn by Cassini has provided many surprises regarding: Saturn's rapidly rotating magnetosphere, interactions with its diverse moons, and interactions with the solar wind. Enceladus, orbiting at 4 Saturn radii (RS), was found to have plumes of water vapour and ice which are the dominant source for the inner magnetosphere. Charged water clusters, charged dust and photoelectrons provide key populations in the 'dusty plasma' observed. Direct pickup is seen near Enceladus and field-aligned currents create a spot in Saturn's aurora. At Titan, orbiting at 20 RS, unexpected heavy negative and positive ions are seen in the ionosphere, which provide the source for Titan's haze. Ionospheric plasma is seen in Titan's tail, enabling ion escape to be estimated at 7 tonnes per day. Saturn's ring ionosphere was seen early in the mission and a return will be made in 2017. In addition, highly accelerated electrons are seen at Saturn's high Mach number (MA˜100) quasi-parallel bow shock. Here we review some of these key new results, and discuss the implications for other solar system objects.
Bruce, Adam L
2015-01-01
We show the traditional rocket problem, where the ejecta velocity is assumed constant, can be reduced to an integral quadrature of which the completely non-relativistic equation of Tsiolkovsky, as well as the fully relativistic equation derived by Ackeret, are limiting cases. By expanding this quadrature in series, it is shown explicitly how relativistic corrections to the mass ratio equation as the rocket transitions from the Newtonian to the relativistic regime can be represented as products of exponential functions of the rocket velocity, ejecta velocity, and the speed of light. We find that even low order correction products approximate the traditional relativistic equation to a high accuracy in flight regimes up to $0.5c$ while retaining a clear distinction between the non-relativistic base-case and relativistic corrections. We furthermore use the results developed to consider the case where the rocket is not moving relativistically but the ejecta stream is, and where the ejecta stream is massless.
Relativistic cosmology; Cosmologia Relativista
Energy Technology Data Exchange (ETDEWEB)
Bastero-Gil, M.
2015-07-01
Relativistic cosmology is nothing but the study of the evolution of our universe expanding from the General Theory of Relativity, which describes the gravitational interaction at any scale and given its character far-reaching is the force that dominate the evolution of the universe. (Author)
Relativistic impulse dynamics.
Swanson, Stanley M
2011-08-01
Classical electrodynamics has some annoying rough edges. The self-energy of charges is infinite without a cutoff. The calculation of relativistic trajectories is difficult because of retardation and an average radiation reaction term. By reconceptuallizing electrodynamics in terms of exchanges of impulses rather than describing it by forces and potentials, we eliminate these problems. A fully relativistic theory using photonlike null impulses is developed. Numerical calculations for a two-body, one-impulse-in-transit model are discussed. A simple relationship between center-of-mass scattering angle and angular momentum was found. It reproduces the Rutherford cross section at low velocities and agrees with the leading term of relativistic distinguishable-particle quantum cross sections (Møller, Mott) when the distance of closest approach is larger than the Compton wavelength of the particle. Magnetism emerges as a consequence of viewing retarded and advanced interactions from the vantage point of an instantaneous radius vector. Radiation reaction becomes the local conservation of energy-momentum between the radiating particle and the emitted impulse. A net action is defined that could be used in developing quantum dynamics without potentials. A reinterpretation of Newton's laws extends them to relativistic motion.
Antippa, Adel F.
2009-01-01
We solve the problem of the relativistic rocket by making use of the relation between Lorentzian and Galilean velocities, as well as the laws of superposition of successive collinear Lorentz boosts in the limit of infinitesimal boosts. The solution is conceptually simple, and technically straightforward, and provides an example of a powerful…
Relativistic length agony continued
Directory of Open Access Journals (Sweden)
Redžić D.V.
2014-01-01
Full Text Available We made an attempt to remedy recent confusing treatments of some basic relativistic concepts and results. Following the argument presented in an earlier paper (Redžić 2008b, we discussed the misconceptions that are recurrent points in the literature devoted to teaching relativity such as: there is no change in the object in Special Relativity, illusory character of relativistic length contraction, stresses and strains induced by Lorentz contraction, and related issues. We gave several examples of the traps of everyday language that lurk in Special Relativity. To remove a possible conceptual and terminological muddle, we made a distinction between the relativistic length reduction and relativistic FitzGerald-Lorentz contraction, corresponding to a passive and an active aspect of length contraction, respectively; we pointed out that both aspects have fundamental dynamical contents. As an illustration of our considerations, we discussed briefly the Dewan-Beran-Bell spaceship paradox and the ‘pole in a barn’ paradox. [Projekat Ministarstva nauke Republike Srbije, br. 171028
Low energy cyclotron for radiocarbon dating
Energy Technology Data Exchange (ETDEWEB)
Welch, J.J.
1984-12-01
The measurement of naturally occurring radioisotopes whose half lives are less than a few hundred million years but more than a few years provides information about the temporal behavior of geologic and climatic processes, the temporal history of meteoritic bodies as well as the production mechanisms of these radioisotopes. A new extremely sensitive technique for measuring these radioisotopes at tandem Van de Graaff and cyclotron facilities has been very successful though the high cost and limited availability have been discouraging. We have built and tested a low energy cyclotron for radiocarbon dating similar in size to a conventional mass spectrometer. These tests clearly show that with the addition of a conventional ion source, the low energy cyclotron can perform the extremely high sensitivity /sup 14/C measurements that are now done at accelerator facilities. We found that no significant background is present when the cyclotron is tuned to accelerate /sup 14/C negative ions and the transmission efficiency is adequate to perform radiocarbon dating on milligram samples of carbon. The internal ion source used did not produce sufficient current to detect /sup 14/C directly at modern concentrations. We show how a conventional carbon negative ion source, located outside the cyclotron magnet, would produce sufficient beam and provide for quick sampling to make radiocarbon dating milligram samples with a modest laboratory instrument feasible.
Current drive by electron cyclotron waves in stellarators
Energy Technology Data Exchange (ETDEWEB)
Castejon, F.; Alejaldre, C.; Coarasa, J. A.
1992-07-01
In this paper we propose a method to estimate the induced current by Electron Cyclotron waves fast enough, from the numerical point of view, to be included in a ray-tracing code, and yet accounting for the complicated geometry of stellarators. Since trapped particle effects are particularly important in this Current Drive method and in stellarator magnetic configuration, they are considered by the modification they introduce in the current drive efficiency. Basically, the method consists of integrating the Fisch and Boozer relativistic efficiency, corrected with the effect of trapped particles, times the absorbed power per momentum interval. This one is calculated for a Maxwellian distribution function, assuming a nearly linear regime. The influence of impurities and of species which are not protons is studied, calculating the efficiency for plasmas with Zeff) - Finally, a numerical analysis particularized to TJ-II stellarator is presented. The absorbed power density is calculated by the ray tracing code RAYS, taking into account the actual microwave beam structure. (Author) 23 refs.
Ion waves driven by shear flow in a relativistic degenerate astrophysical plasma
Indian Academy of Sciences (India)
KHAN SHABBIR A; BAKHTIAR-UD-DIN; ILYAS MUHAMMAD; WAZIR ZAFAR
2016-05-01
We investigate the existence and propagation of low-frequency (in comparison to ion cyclotron frequency) electrostatic ion waves in highly dense inhomogeneous astrophysical magnetoplasma comprising relativistic degenerate electrons and non-degenerate ions. The dispersion equation is obtained by Fourier analysis under mean-field quantum hydrodynamics approximationfor various limits of the ratio of rest mass energy to Fermi energy of electrons, relevant to ultrarelativistic, weakly-relativistic and non-relativistic regimes. It is found that the system admits an oscillatory instability under certain condition in the presence of velocity shear parallel to ambient magnetic field. The dispersive role of plasma density and magnetic field is also discussed parametrically in the scenario of dense and degenerate astrophysical plasmas.
Progress of General Test Stand for Intensive Beam Cyclotron
Institute of Scientific and Technical Information of China (English)
2008-01-01
<正>The general test stand for intensive beam cyclotron is one of the preliminary tasks of BRIF project at CIAE. The test stand, which actually is a small compact cyclotron with designed energy of 10 MeV,
A Shocking Surprise in Stephan's Quintet
2006-01-01
This false-color composite image of the Stephan's Quintet galaxy cluster clearly shows one of the largest shock waves ever seen (green arc). The wave was produced by one galaxy falling toward another at speeds of more than one million miles per hour. The image is made up of data from NASA's Spitzer Space Telescope and a ground-based telescope in Spain. Four of the five galaxies in this picture are involved in a violent collision, which has already stripped most of the hydrogen gas from the interiors of the galaxies. The centers of the galaxies appear as bright yellow-pink knots inside a blue haze of stars, and the galaxy producing all the turmoil, NGC7318b, is the left of two small bright regions in the middle right of the image. One galaxy, the large spiral at the bottom left of the image, is a foreground object and is not associated with the cluster. The titanic shock wave, larger than our own Milky Way galaxy, was detected by the ground-based telescope using visible-light wavelengths. It consists of hot hydrogen gas. As NGC7318b collides with gas spread throughout the cluster, atoms of hydrogen are heated in the shock wave, producing the green glow. Spitzer pointed its infrared spectrograph at the peak of this shock wave (middle of green glow) to learn more about its inner workings. This instrument breaks light apart into its basic components. Data from the instrument are referred to as spectra and are displayed as curving lines that indicate the amount of light coming at each specific wavelength. The Spitzer spectrum showed a strong infrared signature for incredibly turbulent gas made up of hydrogen molecules. This gas is caused when atoms of hydrogen rapidly pair-up to form molecules in the wake of the shock wave. Molecular hydrogen, unlike atomic hydrogen, gives off most of its energy through vibrations that emit in the infrared. This highly disturbed gas is the most turbulent molecular hydrogen ever seen. Astronomers were surprised not only by the turbulence
Improving cancer treatment with cyclotron produced radionuclides
Energy Technology Data Exchange (ETDEWEB)
Larson, S.M. Finn, R.D.
1992-08-04
This report describes the author's continuing long term goal of promoting nuclear medicine applications by improving the scientific basis for tumor diagnosis treatment and treatment follow-up based on the use of cyclotron produced radiotracers in oncology. The program has 3 interactive components: Radiochemistry /Cyclotron; Pharmacology; and Immunology. An essential strategy is as follows: novel radionuclides and radiotracers developed in the Radiochemistry/Cyclotron section under the DOE grant during the 1989--1992 grant period, will be employed in the Pharmacology and Immunology sections of the DOE grant during the 1992--1995 grant period. The development of novel radionuclides and tracers is of course useful in and of itself, but their utility is greatly enhanced by the interaction with the immunology and pharmacology components of the program.
Cyclotron resonance absorption in ionospheric plasma
Energy Technology Data Exchange (ETDEWEB)
Villalon, E. (Northeastern Univ., Boston, MA (USA) Geophysics Lab., Hanscom AFB, MA (USA))
1991-04-01
The mode conversion of ordinary polarized electromagnetic waves into electrostatic cyclotron waves in the inhomogeneous ionospheric plasma is investigated. Near resonance the warm plasma dispersion relation is a function of the angle {theta} between the geomagnetic field and the density gradient and of the wave frequency {omega}, where {Omega} {le} {omega} {le} 2{Omega} and {Omega} is the electron cyclotron frequency. The differential equations describing the electric field amplitudes near the plasma resonance are studied, including damping at the second gyroharmonic. For certain values of {omega} and {theta} (e.g., {theta} < 45{degree}, {omega} {approximately} 2{Omega}) the wave equations reduce to the parabolic cylinder equation. The energy transmission coefficients and power absorbed by the cyclotron waves are calculated. The vertical penetration of the plasma wave amplitudes is iestimated using a WKB analysis of the wave equation.
Induced Compton Scattering by Relativistic Electrons in Magnetized Astrophysical Plasmas.
Sincell, Mark William
1994-01-01
The effects of stimulated scattering on high brightness temperature radiation are studied in two important contexts. In the first case, we assume that the radiation is confined to a collimated beam traversing a relativistically streaming magnetized plasma. When the plasma is cold in the bulk frame, stimulated scattering is only significant if the angle between the photon motion and the plasma velocity is less than gamma^{-1} , where gamma is the bulk Lorentz factor. Under the assumption that the center of the photon beam is parallel to the bulk motion, we calculate the scattering rate as a function of the angular spread of the beam and gamma. Magnetization changes the photon recoil, without which stimulated scattering has no effect. It also introduces a strong dependence on frequency and polarization: if the photon frequency matches the electron cyclotron frequency, the scattering rate of photons polarized perpendicular to the magnetic field can be substantially enhanced relative to Thomson, and if the photon frequency is much less than the cyclotron frequency the scattering is suppressed. Applying these calculations to pulsars, we find that stimulated scattering of the radio beam in the magnetized wind believed to exist outside the light cylinder can substantially alter the spectrum and polarization state of the radio signal. We suggest that the scattering rate is so high in some pulsars that the ability of the radio signal to penetrate the pulsar magnetosphere requires modification of either the conventional model of the magnetosphere or assumptions about the effects of stimulated scattering upon a beam. In the second case, we present a model of the radio emission from synchrotron self-absorbed sources, including the effects of induced Compton scattering by the relativistic electrons in the source. Order of magnitude estimates show that stimulated scattering becomes the dominant absorption process when (kTB/m ec^2)tau_{T }_sp{~}> 0.1. Numerical simulations
Relativistic Hydrodynamics with Wavelets
DeBuhr, Jackson; Anderson, Matthew; Neilsen, David; Hirschmann, Eric W
2015-01-01
Methods to solve the relativistic hydrodynamic equations are a key computational kernel in a large number of astrophysics simulations and are crucial to understanding the electromagnetic signals that originate from the merger of astrophysical compact objects. Because of the many physical length scales present when simulating such mergers, these methods must be highly adaptive and capable of automatically resolving numerous localized features and instabilities that emerge throughout the computational domain across many temporal scales. While this has been historically accomplished with adaptive mesh refinement (AMR) based methods, alternatives based on wavelet bases and the wavelet transformation have recently achieved significant success in adaptive representation for advanced engineering applications. This work presents a new method for the integration of the relativistic hydrodynamic equations using iterated interpolating wavelets and introduces a highly adaptive implementation for multidimensional simulati...
Relativistic heavy ion reactions
Energy Technology Data Exchange (ETDEWEB)
Brink, D.M.
1989-08-01
The theory of quantum chromodynamics predicts that if nuclear matter is heated to a sufficiently high temperature then quarks might become deconfined and a quark-gluon plasma could be produced. One of the aims of relativistic heavy ion experiments is to search for this new state of matter. These lectures survey some of the new experimental results and give an introduction to the theories used to interpret them. 48 refs., 4 tabs., 11 figs.
Relativistic spherical plasma waves
Bulanov, S S; Schroeder, C B; Zhidkov, A G; Esarey, E; Leemans, W P
2011-01-01
Tightly focused laser pulses as they diverge or converge in underdense plasma can generate wake waves, having local structures that are spherical waves. Here we report on theoretical study of relativistic spherical wake waves and their properties, including wave breaking. These waves may be suitable as particle injectors or as flying mirrors that both reflect and focus radiation, enabling unique X-ray sources and nonlinear QED phenomena.
Relativistic cosmological hydrodynamics
Hwang, J
1997-01-01
We investigate the relativistic cosmological hydrodynamic perturbations. We present the general large scale solutions of the perturbation variables valid for the general sign of three space curvature, the cosmological constant, and generally evolving background equation of state. The large scale evolution is characterized by a conserved gauge invariant quantity which is the same as a perturbed potential (or three-space curvature) in the comoving gauge.
DEFF Research Database (Denmark)
Oosterbeek, J.W.; Bürger, A.; Westerhof, E.;
2008-01-01
An electron cyclotron emission (ECE) receiver inside the electron cyclotron resonance heating (ECRH) transmission line has been brought into operation. The ECE is extracted by placing a quartz plate acting as a Fabry-Perot interferometer under an angle inside the electron cyclotron wave (ECW) beam...
Relativistic gravity gradiometry
Bini, Donato; Mashhoon, Bahram
2016-12-01
In general relativity, relativistic gravity gradiometry involves the measurement of the relativistic tidal matrix, which is theoretically obtained from the projection of the Riemann curvature tensor onto the orthonormal tetrad frame of an observer. The observer's 4-velocity vector defines its local temporal axis and its local spatial frame is defined by a set of three orthonormal nonrotating gyro directions. The general tidal matrix for the timelike geodesics of Kerr spacetime has been calculated by Marck [Proc. R. Soc. A 385, 431 (1983)]. We are interested in the measured components of the curvature tensor along the inclined "circular" geodesic orbit of a test mass about a slowly rotating astronomical object of mass M and angular momentum J . Therefore, we specialize Marck's results to such a "circular" orbit that is tilted with respect to the equatorial plane of the Kerr source. To linear order in J , we recover the gravitomagnetic beating phenomenon [B. Mashhoon and D. S. Theiss, Phys. Rev. Lett. 49, 1542 (1982)], where the beat frequency is the frequency of geodetic precession. The beat effect shows up as a special long-period gravitomagnetic part of the relativistic tidal matrix; moreover, the effect's short-term manifestations are contained in certain post-Newtonian secular terms. The physical interpretation of this effect is briefly discussed.
Gravitationally confined relativistic neutrinos
Vayenas, C. G.; Fokas, A. S.; Grigoriou, D.
2017-09-01
Combining special relativity, the equivalence principle, and Newton’s universal gravitational law with gravitational rather than rest masses, one finds that gravitational interactions between relativistic neutrinos with kinetic energies above 50 MeV are very strong and can lead to the formation of gravitationally confined composite structures with the mass and other properties of hadrons. One may model such structures by considering three neutrinos moving symmetrically on a circular orbit under the influence of their gravitational attraction, and by assuming quantization of their angular momentum, as in the Bohr model of the H atom. The model contains no adjustable parameters and its solution, using a neutrino rest mass of 0.05 eV/c2, leads to composite state radii close to 1 fm and composite state masses close to 1 GeV/c2. Similar models of relativistic rotating electron - neutrino pairs give a mass of 81 GeV/c2, close to that of W bosons. This novel mechanism of generating mass suggests that the Higgs mass generation mechanism can be modeled as a latent gravitational field which gets activated by relativistic neutrinos.
Relativistic Radiation Mediated Shocks
Budnik, Ran; Sagiv, Amir; Waxman, Eli
2010-01-01
The structure of relativistic radiation mediated shocks (RRMS) propagating into a cold electron-proton plasma is calculated and analyzed. A qualitative discussion of the physics of relativistic and non relativistic shocks, including order of magnitude estimates for the relevant temperature and length scales, is presented. Detailed numerical solutions are derived for shock Lorentz factors $\\Gamma_u$ in the range $6\\le\\Gamma_u\\le30$, using a novel iteration technique solving the hydrodynamics and radiation transport equations (the protons, electrons and positrons are argued to be coupled by collective plasma processes and are treated as a fluid). The shock transition (deceleration) region, where the Lorentz factor $ \\Gamma $ drops from $ \\Gamma_u $ to $ \\sim 1 $, is characterized by high plasma temperatures $ T\\sim \\Gamma m_ec^2 $ and highly anisotropic radiation, with characteristic shock-frame energy of upstream and downstream going photons of a few~$\\times\\, m_ec^2$ and $\\sim \\Gamma^2 m_ec^2$, respectively.P...
Parker, Edward
2017-08-01
A nonrelativistic particle released from rest at the edge of a ball of uniform charge density or mass density oscillates with simple harmonic motion. We consider the relativistic generalizations of these situations where the particle can attain speeds arbitrarily close to the speed of light; generalizing the electrostatic and gravitational cases requires special and general relativity, respectively. We find exact closed-form relations between the position, proper time, and coordinate time in both cases, and find that they are no longer harmonic, with oscillation periods that depend on the amplitude. In the highly relativistic limit of both cases, the particle spends almost all of its proper time near the turning points, but almost all of the coordinate time moving through the bulk of the ball. Buchdahl's theorem imposes nontrivial constraints on the general-relativistic case, as a ball of given density can only attain a finite maximum radius before collapsing into a black hole. This article is intended to be pedagogical, and should be accessible to those who have taken an undergraduate course in general relativity.
Point form relativistic quantum mechanics and relativistic SU(6)
Klink, W. H.
1993-01-01
The point form is used as a framework for formulating a relativistic quantum mechanics, with the mass operator carrying the interactions of underlying constituents. A symplectic Lie algebra of mass operators is introduced from which a relativistic harmonic oscillator mass operator is formed. Mass splittings within the degenerate harmonic oscillator levels arise from relativistically invariant spin-spin, spin-orbit, and tensor mass operators. Internal flavor (and color) symmetries are introduced which make it possible to formulate a relativistic SU(6) model of baryons (and mesons). Careful attention is paid to the permutation symmetry properties of the hadronic wave functions, which are written as polynomials in Bargmann spaces.
Relativistic Transitions in the Hydrogenic Atoms
Boudet, R
2009-01-01
When one approaches the study of the quantal relativistic theory of the electron, one may be surprised by the gap which lies between the frame of the experiments, i.e. the real geometry of the space and time, and the abstraction of the complex matrices and spinors formalism employed in the presentation of the theory. This book uses a theory of the electron, introduced by David Hestenes, in which the mathematical language is the same as the one of the geometry of the space and time. Such a language not only allows one to find again the well known results concerning the one-electron atoms theory but furthermore leads easily to the resolution of problems considered for a long time without solution.
Generation of the jovian radio emission by the maser cyclotron instability: first lessons from JUNO
Louarn, Philippe; Allegrini, Frederic; Kurth, WilliamS.; Valek, Philips. W.; McComas, Dave; Bagenal, Fran; Bolton, Scott; Connerney, John; Ebert, Robert W.; Levin, Steven; Szalay, Jamey; Wilson, Robert; Zink, Jenna; André, Nicolas; Imai, Masafumi
2017-04-01
Using JUNO plasma and wave observations (JADE and Waves instruments), the scenario for the generation of jovian auroral radio emissions are analyzed. The sources of radiation are identified by localized intensifications of the radio flux at frequencies close to the electron gyrofrequency. Not surprisingly, it is shown that the cyclotron maser instability is perfectly adapted to the plasma conditions prevailing in the radio sources. However, it appears that different forms of activation of the cyclotron maser are observed. For radiation at hectometric wavelengths (one of the main emissions), pronounced loss-cones in the electron distribution functions are likely the source of free energy. The sources would be extended over several thousand km in directions traverse to the magnetic field. The applications of the theory reveals that sufficient growth rates are obtained from the distributions functions that are actually measured by JADE. This differs from the Earth scenario for which 'trapped' distribution functions drive the maser. More localized sources are also observed, possibly linked to local acceleration process. These examples may present analogies with the 'Earth' scenario, with other forms of free energy than the loss-cone. A first lesson of these direct in-situ JADE and RPWS observations is thus to confirm the maser cyclotron scenario with, however, conditions for the wave amplification and detailed maser processes that appear to be different than at Earth.
Imaging Cyclotron Orbits of Electrons in Graphene.
Bhandari, Sagar; Lee, Gil-Ho; Klales, Anna; Watanabe, Kenji; Taniguchi, Takashi; Heller, Eric; Kim, Philip; Westervelt, Robert M
2016-03-09
Electrons in graphene can travel for several microns without scattering at low temperatures, and their motion becomes ballistic, following classical trajectories. When a magnetic field B is applied perpendicular to the plane, electrons follow cyclotron orbits. Magnetic focusing occurs when electrons injected from one narrow contact focus onto a second contact located an integer number of cyclotron diameters away. By tuning the magnetic field B and electron density n in the graphene layer, we observe magnetic focusing peaks. We use a cooled scanning gate microscope to image cyclotron trajectories in graphene at 4.2 K. The tip creates a local change in density that casts a shadow by deflecting electrons flowing nearby; an image of flow can be obtained by measuring the transmission between contacts as the tip is raster scanned across the sample. On the first magnetic focusing peak, we image a cyclotron orbit that extends from one contact to the other. In addition, we study the geometry of orbits deflected into the second point contact by the tip.
Tokamak startup with electron cyclotron heating
Energy Technology Data Exchange (ETDEWEB)
Holly, D J; Prager, S C; Shepard, D A; Sprott, J C
1980-04-01
Experiments are described in which the startup voltage in a tokamak is reduced by approx. 60% by the use of a modest amount of electron cyclotron resonance heating power for preionization. A 50% reduction in volt-second requirement and impurity reflux are also observed.
1971-01-01
One of the 14 pancakes of the new magnet coils for the 600 MeV synchro-cyclotron which were wound and coated with epoxy resin on the CERN site. These new coils will replace the present ones which have been in use for more than 14 years but are now showing signs of deteriorations.
Stability of the Electron Cyclotron Resonance
Asch, Joachim; Bourget, Olivier; Meresse, Cédric
2015-12-01
We consider the magnetic AC Stark effect for the quantum dynamics of a single particle in the plane under the influence of an oscillating homogeneous electric and a constant perpendicular magnetic field. We prove that the electron cyclotron resonance is insensitive to impurity potentials.
Cyclotron-based neutron source for BNCT
Mitsumoto, T.; Yajima, S.; Tsutsui, H.; Ogasawara, T.; Fujita, K.; Tanaka, H.; Sakurai, Y.; Maruhashi, A.
2013-04-01
Kyoto University Research Reactor Institute (KURRI) and Sumitomo Heavy Industries, Ltd. (SHI) have developed a cyclotron-based neutron source for Boron Neutron Capture Therapy (BNCT). It was installed at KURRI in Osaka prefecture. The neutron source consists of a proton cyclotron named HM-30, a beam transport system and an irradiation & treatment system. In the cyclotron, H- ions are accelerated and extracted as 30 MeV proton beams of 1 mA. The proton beams is transported to the neutron production target made by a beryllium plate. Emitted neutrons are moderated by lead, iron, aluminum and calcium fluoride. The aperture diameter of neutron collimator is in the range from 100 mm to 250 mm. The peak neutron flux in the water phantom is 1.8×109 neutrons/cm2/sec at 20 mm from the surface at 1 mA proton beam. The neutron source have been stably operated for 3 years with 30 kW proton beam. Various pre-clinical tests including animal tests have been done by using the cyclotron-based neutron source with 10B-p-Borono-phenylalanine. Clinical trials of malignant brain tumors will be started in this year.
Development of the cyclotron radioisotope production technology
Energy Technology Data Exchange (ETDEWEB)
Suh, Yong Sup; Chun, K.S.; Yang, S.D.; Lee, J.D.; Ahn, S.H.; Yun, Y.K.; Park, H.; Lee, J.S.; Chai, J.S.; Kim, U.S.; Hong, S.S.; Lee, M.Y.; Park, C.W.; Baik, S. K.; Kim, E. H.; Kim, T. K.; Kim, K. S.; Kim, J. H
1999-04-01
The purpose of this study is to contribute the advance of nuclear medicine and to the improvement of human health through the development of various accelerator radionuclides and mass production with automization of production. The results obtained from this study are following: 1) In order to introduce 30 MeV high current cyclotron, the specification of cyclotron has been made, the building site was selected and we drew the draw-up of cyclotron. The cyclotron installation contract was postponed until the financial resources could be secured. 2) For a development high purity 1-123 producing system, a Xe-124 target system, a temperature measurement system of the inner part of the target and a target window were fabricated. A Xe-124 gas target recovery system and a full production system of 1-123 was drew up. 3) For a development of a therapeutic nuclide At-211, a target for the production of At-211 via {sup 209}Bi(alpha, 2n) reaction was fabricated. Produced At-211 was separated by distillation method. 4) For development of beta-emitting nuclides, Ti-45, C-11, F{sub 2}-18, beam irradiation system suitable for each target were fabricated. 5) For automatic production of Ga-67, automated module and PLC program was made 6) For the quality control of radiopharmaceuticals, analytical method of thallium and copper by polarography was investigated and established.
SC Cyclotron and RIB Facilities in Kolkata
Sinha, Bikash; Chakrabarti, Alok
2005-01-01
The superconducting cyclotron under construction at this Centre has bending limit (K-bend) of 520 and focusing limit (K-foc) of 160. It is being constructed, primarily, for nuclear physics experiments with heavy ion beams at intermediate energies. The 100-ton main magnet is currently in the commissioning phase with the main coil already at 4.2K temperature. Magnetic field measurements will be carried out over the next several months. All other systems of the cyclotron are in an advanced stage of fabrication or development. We plan to start assembly of the complete cyclotron around the end of 2005. In the phase-I of the project one beam line has been provided. Construction of three more beam lines and various experimental facilities for nuclear physics as well as irradiation experiments has also been funded and the work is well on its way. An ISOL type Radioactive Ion Beam (RIB) facility is being built with the existing K=130 room temperature cyclotron, VEC, as the primary beam source. In-beam RIB production a...
The irradiation facility at the AGOR cyclotron
Brandenburg, Sytze; Ostendorf, Reint; Hofstee, Mariet; Kiewiet, Harry; Beijers, Hans
2007-01-01
The KVI is conducting radiobiology research using protons up to 190 MeV from the superconducting AGOR cyclotron in collaboration with the University Medical Center Groningen (UMCG) since 1998. Using the same set-up, we have started irradiations for radiation hardness studies of detectors and compone
Electron cyclotron resonance heating on TEXTOR
Westerhof, E.; Hoekzema, J. A.; Hogeweij, G. M. D.; Jaspers, R. J. E.; Schüller, F. C.; Barth, C. J.; Bongers, W. A.; Donne, A. J. H.; Dumortier, P.; van der Grift, A. F.; van Gorkom, J. C.; Kalupin, D.; Koslowski, H. R.; Kramer-Flecken, A.; Kruijt, O. G.; Cardozo, N. J. L.; Mantica, P.; van der Meiden, H. J.; Merkulov, A.; Messiaen, A.; Oosterbeek, J. W.; Oyevaar, T.; Poelman, A. J.; Polman, R. W.; Prins, P. R.; Scholten, J.; Sterk, A. B.; Tito, C. J.; Udintsev, V.S.; Unterberg, B.; Vervier, M.; van Wassenhove, G.
2003-01-01
The 110 GHz and the new 140 GHz gyrotron systems for electron cyclotron resonance heating (ECRH) and ECCD on TEXTOR are described and results of ECRH experiments with the 110 GHz system are reported. Central ECRH on Ohmic plasmas shows the presence of an internal electron transport barrier near q =
Cyclotron-based neutron source for BNCT
Energy Technology Data Exchange (ETDEWEB)
Mitsumoto, T.; Yajima, S.; Tsutsui, H.; Ogasawara, T.; Fujita, K. [Sumitomo Heavy Industries, Ltd (Japan); Tanaka, H.; Sakurai, Y.; Maruhashi, A. [Kyoto University Research Reactor Institute (Japan)
2013-04-19
Kyoto University Research Reactor Institute (KURRI) and Sumitomo Heavy Industries, Ltd. (SHI) have developed a cyclotron-based neutron source for Boron Neutron Capture Therapy (BNCT). It was installed at KURRI in Osaka prefecture. The neutron source consists of a proton cyclotron named HM-30, a beam transport system and an irradiation and treatment system. In the cyclotron, H- ions are accelerated and extracted as 30 MeV proton beams of 1 mA. The proton beams is transported to the neutron production target made by a beryllium plate. Emitted neutrons are moderated by lead, iron, aluminum and calcium fluoride. The aperture diameter of neutron collimator is in the range from 100 mm to 250 mm. The peak neutron flux in the water phantom is 1.8 Multiplication-Sign 109 neutrons/cm{sup 2}/sec at 20 mm from the surface at 1 mA proton beam. The neutron source have been stably operated for 3 years with 30 kW proton beam. Various pre-clinical tests including animal tests have been done by using the cyclotron-based neutron source with {sup 10}B-p-Borono-phenylalanine. Clinical trials of malignant brain tumors will be started in this year.
Relativistic magnetohydrodynamics in one dimension.
Lyutikov, Maxim; Hadden, Samuel
2012-02-01
We derive a number of solutions for one-dimensional dynamics of relativistic magnetized plasma that can be used as benchmark estimates in relativistic hydrodynamic and magnetohydrodynamic numerical codes. First, we analyze the properties of simple waves of fast modes propagating orthogonally to the magnetic field in relativistically hot plasma. The magnetic and kinetic pressures obey different equations of state, so that the system behaves as a mixture of gases with different polytropic indices. We find the self-similar solutions for the expansion of hot strongly magnetized plasma into vacuum. Second, we derive linear hodograph and Darboux equations for the relativistic Khalatnikov potential, which describe arbitrary one-dimensional isentropic relativistic motion of cold magnetized plasma and find their general and particular solutions. The obtained hodograph and Darboux equations are very powerful: A system of highly nonlinear, relativistic, time-dependent equations describing arbitrary (not necessarily self-similar) dynamics of highly magnetized plasma reduces to a single linear differential equation.
The Influence of Negative Surprise on Hedonic Adaptation
Directory of Open Access Journals (Sweden)
Ana Paula Kieling
2016-01-01
Full Text Available After some time using a product or service, the consumer tends to feel less pleasure with consumption. This reduction of pleasure is known as hedonic adaptation. One of the emotions that interfere in this process is surprise. Based on two experiments, we suggest that negative surprise – differently to positive – influences with the level of pleasure foreseen and experienced by the consumer. Study 1 analyzes the influence of negative (vs. positive surprise on the consumer’s post-purchase hedonic adaptation expectation. Results showed that negative surprise influences the intensity of adaptation, augmenting its strength. Study 2 verifies the influence of negative (vs positive surprise over hedonic adaptation. The findings suggested that negative surprise makes adaptation happen more intensively and faster as time goes by, which brings consequences to companies and consumers in the post-purchase process, such as satisfaction and loyalty.
Effects of Surprisal and Locality on Danish Sentence Processing
DEFF Research Database (Denmark)
Balling, Laura Winther; Kizach, Johannes
2017-01-01
An eye-tracking experiment in Danish investigates two dominant accounts of sentence processing: locality-based theories that predict a processing advantage for sentences where the distance between the major syntactic heads is minimized, and the surprisal theory which predicts that processing time...... constructions with two postverbal NP-objects. An eye-tracking experiment showed a clear advantage for local syntactic relations, with only a marginal effect of lexicalised surprisal and no effect of syntactic surprisal. We conclude that surprisal has a relatively marginal effect, which may be clearest for verbs...
Mushtukov, Alexander A.; Tsygankov, Sergey S.; Serber, Alexander V.; Suleimanov, Valery F.; Poutanen, Juri
2015-12-01
Cyclotron resonance scattering features observed in the spectra of some X-ray pulsars show significant changes of the line centroid energy with the pulsar luminosity. Whereas for bright sources above the so-called critical luminosity, these variations are established to be connected with the appearance of the high-accretion column above the neutron star surface, at low, sub-critical luminosities the nature of the variations (but with the opposite sign) has not been discussed widely. We argue here that the cyclotron line is formed when the radiation from a hotspot propagates through the plasma falling with a mildly relativistic velocity on to the neutron star surface. The position of the cyclotron resonance is determined by the Doppler effect. The change of the cyclotron line position in the spectrum with luminosity is caused by variations of the velocity profile in the line-forming region affected by the radiation pressure force. The presented model has several characteristic features: (i) the line centroid energy is positively correlated with the luminosity; (ii) the line width is positively correlated with the luminosity as well; (iii) the position and the width of the cyclotron absorption line are variable over the pulse phase; (iv) the line has a more complicated shape than widely used Lorentzian or Gaussian profiles; (v) the phase-resolved cyclotron line centroid energy and the width are negatively and positively correlated with the pulse intensity, respectively. The predictions of the proposed theory are compared with the variations of the cyclotron line parameters in the X-ray pulsar GX 304-1 over a wide range of sub-critical luminosities as seen by the INTEGRAL observatory.
Recurrence relation for relativistic atomic matrix elements
Martínez y Romero, R P; Salas-Brito, A L
2000-01-01
Recurrence formulae for arbitrary hydrogenic radial matrix elements are obtained in the Dirac form of relativistic quantum mechanics. Our approach is inspired on the relativistic extension of the second hypervirial method that has been succesfully employed to deduce an analogous relationship in non relativistic quantum mechanics. We obtain first the relativistic extension of the second hypervirial and then the relativistic recurrence relation. Furthermore, we use such relation to deduce relativistic versions of the Pasternack-Sternheimer rule and of the virial theorem.
Relativistic twins or sextuplets?
Sheldon, E S
2003-01-01
A recent study of the relativistic twin 'paradox' by Soni in this journal affirmed that 'A simple solution of the twin paradox also shows anomalous behaviour of rigidly connected distant clocks' but entailed a pedagogic hurdle which the present treatment aims to surmount. Two scenarios are presented: the first 'flight-plan' is akin to that depicted by Soni, with constant-velocity segments, while the second portrays an alternative mission undertaken with sustained acceleration and deceleration, illustrated quantitatively for a two-way spacecraft flight from Earth to Polaris (465.9 light years distant) and back.
Numerical Relativistic Quantum Optics
2013-11-08
µm and a = 1. The condition for an atomic spectrum to be non-relativistic is Z α−1 ≈ 137, as follows from elementary Dirac theory. One concludes that...peculiar result that B0 = 1 TG is a weak field. At present, such fields are observed only in connection with astrophysical phenomena [14]. The highest...pulsars. The Astrophysical Journal, 541:367–373, Sep 2000. [15] M. Tatarakis, I. Watts, F.N. Beg, E.L. Clark, A.E. Dangor, A. Gopal, M.G. Haines, P.A
Corinaldesi, Ernesto
1963-01-01
Geared toward advanced undergraduate and graduate students of physics, this text provides readers with a background in relativistic wave mechanics and prepares them for the study of field theory. The treatment originated as a series of lectures from a course on advanced quantum mechanics that has been further amplified by student contributions.An introductory section related to particles and wave functions precedes the three-part treatment. An examination of particles of spin zero follows, addressing wave equation, Lagrangian formalism, physical quantities as mean values, translation and rotat
Rössler, O E; Matsuno, K
1998-04-01
The two mindsets of absolutism and relativism are juxtaposed, and the relational or relativist stance is vindicated. The only 'absolute' entity which undeniably exists, consciousness has the reality of a dream. The escape hatch from this prison is relational, as Descartes and Levinas found out: Unfalsified relational consistency implies exteriority. Exteriority implies infinite power which in turn makes compassion inevitable. Aside from ethics as a royal way to enlightenment, a new technology called 'deep technology' may be accessible. It changes the whole world in a demonstrable fashion by manipulation of the micro frame--that is, the observer-world interface.
Surprise and Sense Making: Undergraduate Placement Experiences in SMEs
Walmsley, Andreas; Thomas, Rhodri; Jameson, Stephanie
2006-01-01
Purpose: This paper seeks to explore undergraduate placement experiences in tourism and hospitality SMEs, focusing on the notions of surprise and sense making. It aims to argue that surprises and sense making are important elements not only of the adjustment process when entering new work environments, but also of the learning experience that…
Ion Injection at Non-relativistic Collisionless Shocks
Caprioli, Damiano; Spitkovsky, Anatoly
2014-01-01
We use kinetic hybrid simulations (kinetic ions - fluid electrons) to characterize the fraction of ions that are accelerated to non-thermal energies at non-relativistic collisionless shocks. We investigate the properties of the shock discontinuity and show that shocks propagating almost along the background magnetic field (quasi-parallel shocks) reform quasi-periodically on ion cyclotron scales. Ions that impinge on the shock when the discontinuity is the steepest are specularly reflected. This is a necessary condition for being injected, but it is not sufficient. Also by following the trajectories of reflected ions, we calculate the minimum energy needed for injection into diffusive shock acceleration, as a function of the shock inclination. We construct a minimal model that accounts for the ion reflection from quasi-periodic shock barrier, for the fraction of injected ions, and for the ion spectrum throughout the transition from thermal to non-thermal energies. This model captures the physics relevant for i...
Neural Responses to Rapid Facial Expressions of Fear and Surprise
Directory of Open Access Journals (Sweden)
Ke Zhao
2017-05-01
Full Text Available Facial expression recognition is mediated by a distributed neural system in humans that involves multiple, bilateral regions. There are six basic facial expressions that may be recognized in humans (fear, sadness, surprise, happiness, anger, and disgust; however, fearful faces and surprised faces are easily confused in rapid presentation. The functional organization of the facial expression recognition system embodies a distinction between these two emotions, which is investigated in the present study. A core system that includes the right parahippocampal gyrus (BA 30, fusiform gyrus, and amygdala mediates the visual recognition of fear and surprise. We found that fearful faces evoked greater activity in the left precuneus, middle temporal gyrus (MTG, middle frontal gyrus, and right lingual gyrus, whereas surprised faces were associated with greater activity in the right postcentral gyrus and left posterior insula. These findings indicate the importance of common and separate mechanisms of the neural activation that underlies the recognition of fearful and surprised faces.
Exotic Non-relativistic String
Casalbuoni, Roberto; Longhi, Giorgio
2007-01-01
We construct a classical non-relativistic string model in 3+1 dimensions. The model contains a spurion tensor field that is responsible for the non-commutative structure of the model. Under double dimensional reduction the model reduces to the exotic non-relativistic particle in 2+1 dimensions.
'Antigravity' Propulsion and Relativistic Hyperdrive
Felber, F S
2006-01-01
Exact payload trajectories in the strong gravitational fields of compact masses moving with constant relativistic velocities are calculated. The strong field of a suitable driver mass at relativistic speeds can quickly propel a heavy payload from rest to a speed significantly faster than the driver, a condition called hyperdrive. Hyperdrive thresholds and maxima are calculated as functions of driver mass and velocity.
A Simple Relativistic Bohr Atom
Terzis, Andreas F.
2008-01-01
A simple concise relativistic modification of the standard Bohr model for hydrogen-like atoms with circular orbits is presented. As the derivation requires basic knowledge of classical and relativistic mechanics, it can be taught in standard courses in modern physics and introductory quantum mechanics. In addition, it can be shown in a class that…
A Simple Relativistic Bohr Atom
Terzis, Andreas F.
2008-01-01
A simple concise relativistic modification of the standard Bohr model for hydrogen-like atoms with circular orbits is presented. As the derivation requires basic knowledge of classical and relativistic mechanics, it can be taught in standard courses in modern physics and introductory quantum mechanics. In addition, it can be shown in a class that…
Komissarov, S S; Lyutikov, M
2015-01-01
In this paper we describe a simple numerical approach which allows to study the structure of steady-state axisymmetric relativistic jets using one-dimensional time-dependent simulations. It is based on the fact that for narrow jets with v~c the steady-state equations of relativistic magnetohydrodynamics can be accurately approximated by the one-dimensional time-dependent equations after the substitution z=ct. Since only the time-dependent codes are now publicly available this is a valuable and efficient alternative to the development of a high-specialized code for the time-independent equations. The approach is also much cheaper and more robust compared to the relaxation method. We tested this technique against numerical and analytical solutions found in literature as well as solutions we obtained using the relaxation method and found it sufficiently accurate. In the process, we discovered the reason for the failure of the self-similar analytical model of the jet reconfinement in relatively flat atmospheres a...
Robust relativistic bit commitment
Chakraborty, Kaushik; Chailloux, André; Leverrier, Anthony
2016-12-01
Relativistic cryptography exploits the fact that no information can travel faster than the speed of light in order to obtain security guarantees that cannot be achieved from the laws of quantum mechanics alone. Recently, Lunghi et al. [Phys. Rev. Lett. 115, 030502 (2015), 10.1103/PhysRevLett.115.030502] presented a bit-commitment scheme where each party uses two agents that exchange classical information in a synchronized fashion, and that is both hiding and binding. A caveat is that the commitment time is intrinsically limited by the spatial configuration of the players, and increasing this time requires the agents to exchange messages during the whole duration of the protocol. While such a solution remains computationally attractive, its practicality is severely limited in realistic settings since all communication must remain perfectly synchronized at all times. In this work, we introduce a robust protocol for relativistic bit commitment that tolerates failures of the classical communication network. This is done by adding a third agent to both parties. Our scheme provides a quadratic improvement in terms of expected sustain time compared with the original protocol, while retaining the same level of security.
Heating and Current Drive by Electron Cyclotron Waves
Prater, R.
2003-10-01
The physics model of electron cyclotron heating (ECH) and current drive (ECCD) is becoming well validated through systematic comparisons of theory and experiment. Work has shown that ECCD can be highly localized and robustly controlled, leading to applications including stabilization of MHD instabilities like neoclassical tearing modes, control and sustainment of desired profiles of current density and plasma pressure, and studies of localized transport. These physics applications and the study of the basic physics of ECH and ECCD were enabled by the advent of the gyrotron in the 1980s and of the diamond window for megawatt gyrotrons in the 1990s. The experimental work stimulated a broad base of theory based on first principles which is encapsulated in linear ray tracing codes and fully relativistic quasilinear Fokker-Planck codes. Recent experiments use measurements of the local poloidal magnetic field through the motional Stark effect to determine the magnitude and profile of the locally driven current. The subtle balance between wave-induced diffusion and Coulomb relaxation in velocity space provides an understanding of the effects of trapping of current-carrying electrons in the magnetic well, an effect which can be used to advantage. Strong quasilinear effects and radial transport of electrons which may broaden the driven current profile have also been observed under some conditions and appear to be consistent with theory, but in large devices these are usually insignificant. Additional advantages of ECH compared with other rf heating methods are that the antenna can be far removed from the plasma and the power density can be very high. The agreement of theory and experiment, the broad base of established applications, and the technical advantages of ECH support the application of ECH in next-step tokamaks and stellarators.
Ring Current-Electromagnetic Ion Cyclotron Waves Coupling
Khazanov, G. V.
2005-01-01
The effect of Electromagnetic Ion Cyclotron (EMIC) waves, generated by ion temperature anisotropy in Earth s ring current (RC), is the best known example of wave- particle interaction in the magnetosphere. Also, there is much controversy over the importance of EMIC waves on RC depletion. Under certain conditions, relativistic electrons, with energies 21 MeV, can be removed from the outer radiation belt (RB) by EMIC wave scattering during a magnetic storm. That is why the calculation of EMIC waves must be a very critical part of the space weather studies. The new RC model that we have developed and present for the first time has several new features that we have combine together in a one single model: (a) several lower frequency cold plasma wave modes are taken into account; (b) wave tracing of these wave has been incorporated in the energy EMIC wave equation; (c) no assumptions regarding wave shape spectra have been made; (d) no assumptions regarding the shape of particle distribution have been made to calculate the growth rate; (e) pitch-angle, energy, and mix diffusions are taken into account together for the first time; (f) the exact loss-cone RC analytical solution has been found and coupled with bounce-averaged numerical solution of kinetic equation; (g) the EMIC waves saturation due to their modulation instability and LHW generation are included as an additional factor that contributes to this process; and (h) the hot ions were included in the real part of dielectric permittivity tensor. We compare our theoretical results with the different EMIC waves models as well as RC experimental data.
Fractional Dynamics of Relativistic Particle
Tarasov, Vasily E
2011-01-01
Fractional dynamics of relativistic particle is discussed. Derivatives of fractional orders with respect to proper time describe long-term memory effects that correspond to intrinsic dissipative processes. Relativistic particle subjected to a non-potential four-force is considered as a nonholonomic system. The nonholonomic constraint in four-dimensional space-time represents the relativistic invariance by the equation for four-velocity u_{\\mu} u^{\\mu}+c^2=0, where c is a speed of light in vacuum. In the general case, the fractional dynamics of relativistic particle is described as non-Hamiltonian and dissipative. Conditions for fractional relativistic particle to be a Hamiltonian system are considered.
Fourier Transform Ion Cyclotron Resonance Mass Spectrometry at the Cyclotron Frequency
Nagornov, Konstantin O.; Kozhinov, Anton N.; Tsybin, Yury O.
2017-02-01
The phenomenon of ion cyclotron resonance allows for determining mass-to-charge ratio, m/z, of an ensemble of ions by means of measurements of their cyclotron frequency, ω c . In Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS), the ω c quantity is usually unavailable for direct measurements: the resonant state is located close to the reduced cyclotron frequency (ω+), whereas the ω c and the corresponding m/z values may be calculated via theoretical derivation from an experimental estimate of the ω+ quantity. Here, we describe an experimental observation of a new resonant state, which is located close to the ω c frequency and is established because of azimuthally-dependent trapping electric fields of the recently developed ICR cells with narrow aperture detection electrodes. We show that in mass spectra, peaks close to ω+ frequencies can be reduced to negligible levels relative to peaks close to ω c frequencies. Due to reduced errors with which the ω c quantity is obtained, the new resonance provides a means of cyclotron frequency measurements with precision greater than that achieved when ω+ frequency peaks are employed. The described phenomenon may be considered for a development into an FT-ICR MS technology with increased mass accuracy for applications in basic research, life, and environmental sciences.
Fourier Transform Ion Cyclotron Resonance Mass Spectrometry at the Cyclotron Frequency.
Nagornov, Konstantin O; Kozhinov, Anton N; Tsybin, Yury O
2017-04-01
The phenomenon of ion cyclotron resonance allows for determining mass-to-charge ratio, m/z, of an ensemble of ions by means of measurements of their cyclotron frequency, ω c . In Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS), the ω c quantity is usually unavailable for direct measurements: the resonant state is located close to the reduced cyclotron frequency (ω+), whereas the ω c and the corresponding m/z values may be calculated via theoretical derivation from an experimental estimate of the ω+ quantity. Here, we describe an experimental observation of a new resonant state, which is located close to the ω c frequency and is established because of azimuthally-dependent trapping electric fields of the recently developed ICR cells with narrow aperture detection electrodes. We show that in mass spectra, peaks close to ω+ frequencies can be reduced to negligible levels relative to peaks close to ω c frequencies. Due to reduced errors with which the ω c quantity is obtained, the new resonance provides a means of cyclotron frequency measurements with precision greater than that achieved when ω+ frequency peaks are employed. The described phenomenon may be considered for a development into an FT-ICR MS technology with increased mass accuracy for applications in basic research, life, and environmental sciences. Graphical Abstract ᅟ.
TFTR Michelson interferometer electron cyclotron emission diagnostic
Energy Technology Data Exchange (ETDEWEB)
Stauffer, F.J.; Boyd, D.A.; Cutler, R.C.; McCarthy, M.P.
1985-05-01
In July 1984, a Fourier transform spectrometer employing a fast-scanning Michelson interferometer began operating on TFTR. This diagnostic system can measure the electron cyclotron emission spectrum 72 times per s with a time resolution of 11 ms and a spectral resolution of 3.6 GHz. The initial operating spectral range is 75--540 GHz, which is adequate for measuring the first three cyclotron harmonics at present TFTR magnetic field levels. The range can be extended easily to 75--1080 GHz in order to accommodate increases in toroidal magnetic field or to study superthermal ECE. The measured spectra are absolutely calibrated using a liquid nitrogen cooled blackbody reference source. The second harmonic feature of each spectrum is used to calculate the absolute electron temperature profile.
Hybrid simulation of electron cyclotron resonance heating
Ropponen, T; Suominen, P; Koponen, T K; Kalvas, T; Koivisto, H
2008-01-01
Electron Cyclotron Resonance (ECR) heating is a fundamentally important aspect in understanding the physics of Electron Cyclotron Resonance Ion Sources (ECRIS). Absorption of the radio frequency (RF) microwave power by electron heating in the resonance zone depends on many parameters including frequency and electric field strength of the microwave, magnetic field structure and electron and ion density profiles. ECR absorption has been studied in the past by e.g. modelling electric field behaviour in the resonance zone and its near proximity. This paper introduces a new ECR heating code that implements damping of the microwave power in the vicinity of the resonance zone, utilizes electron density profiles and uses right hand circularly polarized (RHCP) electromagnetic waves to simulate electron heating in ECRIS plasma.
Cyclotrons as Drivers for Precision Neutrino Measurements
Directory of Open Access Journals (Sweden)
A. Adelmann
2014-01-01
Full Text Available As we enter the age of precision measurement in neutrino physics, improved flux sources are required. These must have a well defined flavor content with energies in ranges where backgrounds are low and cross-section knowledge is high. Very few sources of neutrinos can meet these requirements. However, pion/muon and isotope decay-at-rest sources qualify. The ideal drivers for decay-at-rest sources are cyclotron accelerators, which are compact and relatively inexpensive. This paper describes a scheme to produce decay-at-rest sources driven by such cyclotrons, developed within the DAEδALUS program. Examples of the value of the high precision beams for pursuing Beyond Standard Model interactions are reviewed. New results on a combined DAEδALUS—Hyper-K search for CP violation that achieve errors on the mixing matrix parameter of 4° to 12° are presented.
Hybrid simulation of electron cyclotron resonance heating
Energy Technology Data Exchange (ETDEWEB)
Ropponen, T. [Department of Physics, University of Jyvaeskylae, P.O. Box 35, FI-40014 (Finland)], E-mail: tommi.ropponen@phys.jyu.fi; Tarvainen, O. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Suominen, P. [CERN Geneve 23, CH-1211 (Switzerland); Koponen, T.K. [Department of Physics, University of Jyvaeskylae, Nanoscience Center, P.O. Box 35, FI-40014 (Finland); Kalvas, T.; Koivisto, H. [Department of Physics, University of Jyvaeskylae, P.O. Box 35, FI-40014 (Finland)
2008-03-11
Electron Cyclotron Resonance (ECR) heating is a fundamentally important aspect in understanding the physics of Electron Cyclotron Resonance Ion Sources (ECRIS). Absorption of the radio frequency (RF) microwave power by electron heating in the resonance zone depends on many parameters including frequency and electric field strength of the microwave, magnetic field structure and electron and ion density profiles. ECR absorption has been studied in the past by e.g. modelling electric field behaviour in the resonance zone and its near proximity. This paper introduces a new ECR heating code that implements damping of the microwave power in the vicinity of the resonance zone, utilizes electron density profiles and uses right hand circularly polarized (RHCP) electromagnetic waves to simulate electron heating in ECRIS plasma.
Beam stripping extraction from the VINCY cyclotron
Directory of Open Access Journals (Sweden)
Ristić-Đurović Jasna L.
2006-01-01
Full Text Available The extraction system of a cyclotron guides an ion beam from a spiral acceleration orbit, through an extraction trajectory, into a high energy transport line. The two methods commonly used to direct an ion into the extraction path are deflection, by the electric field of an electrostatic deflector, and ion stripping, by a thin carbon foil. Compared to the electrostatic deflector system, the stripping extraction provides a fast and easy change of the extracted ion energy and is easier to manufacture operate, and maintain. However, the extraction trajectory and dynamics of an ion beam after stripping are highly dependant on the ion energy and specific charge. Thus, when a multipurpose machine such as the VINCY Cyclotron is concerned, it is far from easy to deliver a variety of ion beams into the same high energy transport line and at the same time preserve a reasonable compactness of the extraction system. The front side stripping extraction system of the VINCY Cyclotron provides high (~70 MeV and mid (~30 MeV energy protons, as well as a number of heavy ions in broad energy ranges. The back side stripping extraction system extracts low energy protons (~18 MeV and enables their simultaneous use with high energy protons at the front side of the machine.
Ion Cyclotron Heating on Proto-MPEX
Goulding, R. H.; Caughman, J. B. O.; Rapp, J.; Biewer, T. M.; Campbell, I. H.; Caneses, J. F.; Kafle, N.; Ray, H. B.; Showers, M. A.; Piotrowicz, P. A.
2016-10-01
Ion cyclotron heating will be used on Proto-MPEX (Prototype Material Plasma Exposure eXperiment) to increase heat flux to the target, to produce varying ion energies without substrate biasing, and to vary the extent of the magnetic pre-sheath for the case of a tilted target. A 25 cm long, 9 cm diameter dual half-turn helical ion cyclotron antenna has been installed in the device located at the magnetic field maximum. It couples power to ions via single pass damping of the slow wave at the fundamental resonance, and operates with ω 0.8ωci at the antenna location. It is designed to operate at power levels up to 30 kW, with a later 200 kW upgrade planned. Near term experiments include measuring RF loading at low power as a function of frequency and antenna gap. The plasma is generated by a helicon plasma source that has achieved ne > 5 ×1019m-3 operating with deuterium, as measured downstream from the ion cyclotron antenna location. Measurements will be compared with 1-D and 2-D models of RF coupling. The latest results will be presented. This manuscript has been authored by UT-Battelle, LLC, under Contract No. DE-AC05-00OR22725 with the U.S. Department of Energy.
Transparency of Magnetized Plasma at Cyclotron Frequency
Energy Technology Data Exchange (ETDEWEB)
G. Shvets; J.S. Wurtele
2002-03-14
Electromagnetic radiation is strongly absorbed by a magnetized plasma if the radiation frequency equals the cyclotron frequency of plasma electrons. It is demonstrated that absorption can be completely canceled in the presence of a magnetostatic field of an undulator or a second radiation beam, resulting in plasma transparency at the cyclotron frequency. This effect is reminiscent of the electromagnetically induced transparency (EIT) of the three-level atomic systems, except that it occurs in a completely classical plasma. Unlike the atomic systems, where all the excited levels required for EIT exist in each atom, this classical EIT requires the excitation of the nonlocal plasma oscillation. The complexity of the plasma system results in an index of refraction at the cyclotron frequency that differs from unity. Lagrangian description was used to elucidate the physics and enable numerical simulation of the plasma transparency and control of group and phase velocity. This control naturally leads to applications for electromagnetic pulse compression in the plasma and electron/ion acceleration.
Commercial compact cyclotrons in the 90's
Energy Technology Data Exchange (ETDEWEB)
Milton, B.F
1995-09-01
Cyclotrons continue to be efficient accelerators for radio-isotope production. In recent years, developments in the accelerator technology have greatly increased the practical beam current in these machines while also improving the overall system reliability. These developments combined with the development of new isotopes for medicine and industry, and a retiring of older machines indicate a strong future for commercial cyclotrons. In this paper we will survey recent developments in the areas of cyclotron technology, as they relate to the new generation of commercial cyclotrons. Design criteria for the different types of commercial cyclotrons will be presented, with reference to those demands that differ from those in a research oriented cyclotron project. We will also discuss the possibility of systems designed for higher energies and capable of extracted beam currents of up to 2.0 mA. (author)
Nuclear physics with superconducting cyclotron at Kolkata: Scopes and possibilities
Indian Academy of Sciences (India)
Sailajananda Bhattacharya
2010-08-01
The K500 superconducting cyclotron at the Variable Energy Cyclotron Centre, Kolkata, India is getting ready to deliver its first accelerated ion beam for experiment. At the same time, the nuclear physics programme and related experimental facility development activities are taking shape. A general review of the nuclear physics research opportunities with the superconducting cyclotron and the present status of the development of different detector arrays and other experimental facilities will be presented.
Magnetic Dissipation in Relativistic Jets
Directory of Open Access Journals (Sweden)
Yosuke Mizuno
2016-10-01
Full Text Available The most promising mechanisms for producing and accelerating relativistic jets, and maintaining collimated structure of relativistic jets involve magnetohydrodynamical (MHD processes. We have investigated the magnetic dissipation mechanism in relativistic jets via relativistic MHD simulations. We found that the relativistic jets involving a helical magnetic field are unstable for the current-driven kink instability, which leads to helically distorted structure in relativistic jets. We identified the regions of high current density in filamentary current sheets, indicative of magnetic reconnection, which are associated to the kink unstable regions and correlated to the converted regions of magnetic to kinetic energies of the jets. We also found that an over-pressured relativistic jet leads to the generation of a series of stationary recollimation shocks and rarefaction structures by the nonlinear interaction of shocks and rarefaction waves. The differences in the recollimation shock structure due to the difference of the magnetic field topologies and strengths may be observable through mm-VLBI observations and space-VLBI mission.
Energy Technology Data Exchange (ETDEWEB)
Skalyga, V. [Institute of Applied Physics of Russian Academy of Sciences, 46 Ulyanova st., Nizhny Novgorod (Russian Federation); Lobachevsky State University of Nizhny Novgorod (UNN), 23 Gagarina st., Nizhny Novgorod (Russian Federation); Izotov, I.; Mansfeld, D. [Institute of Applied Physics of Russian Academy of Sciences, 46 Ulyanova st., Nizhny Novgorod (Russian Federation); Kalvas, T.; Koivisto, H.; Komppula, J.; Kronholm, R.; Laulainen, J.; Tarvainen, O. [Department of Physics, University of Jyväskylä, Jyväskylä (Finland)
2015-08-15
Multiple frequency heating is one of the most effective techniques to improve the performance of Electron Cyclotron Resonance (ECR) ion sources. The method increases the beam current and average charge state of the extracted ions and enhances the temporal stability of the ion beams. It is demonstrated in this paper that the stabilizing effect of two-frequency heating is connected with the suppression of electron cyclotron instability. Experimental data show that the interaction between the secondary microwave radiation and the hot electron component of ECR ion source plasmas plays a crucial role in mitigation of the instabilities.
Relativistic Fractal Cosmologies
Ribeiro, Marcelo B
2009-01-01
This article reviews an approach for constructing a simple relativistic fractal cosmology whose main aim is to model the observed inhomogeneities of the distribution of galaxies by means of the Lemaitre-Tolman solution of Einstein's field equations for spherically symmetric dust in comoving coordinates. This model is based on earlier works developed by L. Pietronero and J.R. Wertz on Newtonian cosmology, whose main points are discussed. Observational relations in this spacetime are presented, together with a strategy for finding numerical solutions which approximate an averaged and smoothed out single fractal structure in the past light cone. Such fractal solutions are shown, with one of them being in agreement with some basic observational constraints, including the decay of the average density with the distance as a power law (the de Vaucouleurs' density power law) and the fractal dimension in the range 1 <= D <= 2. The spatially homogeneous Friedmann model is discussed as a special case of the Lemait...
Relativistic Gravothermal Instabilities
Roupas, Zacharias
2014-01-01
The thermodynamic instabilities of the self-gravitating, classical ideal gas are studied in the case of static, spherically symmetric configurations in General Relativity taking into account the Tolman-Ehrenfest effect. One type of instabilities is found at low energies, where thermal energy becomes too weak to halt gravity and another at high energies, where gravitational attraction of thermal pressure overcomes its stabilizing effect. These turning points of stability are found to depend on the total rest mass $\\mathcal{M}$ over the radius $R$. The low energy instability is the relativistic generalization of Antonov instability, which is recovered in the limit $G\\mathcal{M} \\ll R c^2$ and low temperatures, while in the same limit and high temperatures, the high energy instability recovers the instability of the radiation equation of state. In the temperature versus energy diagram of series of equilibria, the two types of gravothermal instabilities make themselves evident as a double spiral! The two energy l...
Lock, Maximilian P E
2016-01-01
The conflict between quantum theory and the theory of relativity is exemplified in their treatment of time. We examine the ways in which their conceptions differ, and describe a semiclassical clock model combining elements of both theories. The results obtained with this clock model in flat spacetime are reviewed, and the problem of generalizing the model to curved spacetime is discussed, before briefly describing an experimental setup which could be used to test of the model. Taking an operationalist view, where time is that which is measured by a clock, we discuss the conclusions that can be drawn from these results, and what clues they contain for a full quantum relativistic theory of time.
Galilean relativistic fluid mechanics
Ván, Péter
2015-01-01
Single component Galilean-relativistic (nonrelativistic) fluids are treated independently of reference frames. The basic fields are given, their balances, thermodynamic relations and the entropy production is calculated. The usual relative basic fields, the mass, momentum and energy densities, the diffusion current density, the pressure tensor and the heat flux are the time- and spacelike components of the third order mass-momentum-energy density tensor according to a velocity field. The transformation rules of the basic fields are derived and prove that the non-equilibrium thermodynamic background theory, that is the Gibbs relation, extensivity condition and the entropy production is absolute, that is independent of the reference frame and also of the fluid velocity. --- Az egykomponensu Galilei-relativisztikus (azaz nemrelativisztikus) disszipativ folyadekokat vonatkoztatasi rendszertol fuggetlenul targyaljuk. Megadjuk az alapmennyisegeket, ezek merlegeit, a termodinamikai osszefuggeseket es kiszamoljuk az ...
Relativistic Runaway Electrons
Breizman, Boris
2014-10-01
This talk covers recent developments in the theory of runaway electrons in a tokamak with an emphasis on highly relativistic electrons produced via the avalanche mechanism. The rapidly growing population of runaway electrons can quickly replace a large part of the initial current carried by the bulk plasma electrons. The magnetic energy associated with this current is typically much greater than the particle kinetic energy. The current of a highly relativistic runaway beam is insensitive to the particle energy, which separates the description of the runaway current evolution from the description of the runaway energy spectrum. A strongly anisotropic distribution of fast electrons is generally prone to high-frequency kinetic instabilities that may cause beneficial enhancement of runaway energy losses. The relevant instabilities are in the frequency range of whistler waves and electron plasma waves. The instability thresholds reported in earlier work have been revised considerably to reflect strong dependence of collisional damping on the wave frequency and the role of plasma non-uniformity, including radial trapping of the excited waves in the plasma. The talk also includes a discussion of enhanced scattering of the runaways as well as the combined effect of enhanced scattering and synchrotron radiation. A noteworthy feature of the avalanche-produced runaway current is a self-sustained regime of marginal criticality: the inductive electric field has to be close to its critical value (representing avalanche threshold) at every location where the runaway current density is finite, and the current density should vanish at any point where the electric field drops below its critical value. This nonlinear Ohm's law enables complete description of the evolving current profile. Work supported by the U.S. Department of Energy Contract No. DEFG02-04ER54742 and by ITER contract ITER-CT-12-4300000273. The views and opinions expressed herein do not necessarily reflect those of
A finite Zitterbewegung model for relativistic quantum mechanics
Energy Technology Data Exchange (ETDEWEB)
Noyes, H.P.
1990-02-19
Starting from steps of length h/mc and time intervals h/mc{sup 2}, which imply a quasi-local Zitterbewegung with velocity steps {plus minus}c, we employ discrimination between bit-strings of finite length to construct a necessary 3+1 dimensional event-space for relativistic quantum mechanics. By using the combinatorial hierarchy to label the strings, we provide a successful start on constructing the coupling constants and mass ratios implied by the scheme. Agreement with experiments is surprisingly accurate. 22 refs., 1 fig.
What is "Relativistic Canonical Quantization"?
Arbatsky, D. A.
2005-01-01
The purpose of this review is to give the most popular description of the scheme of quantization of relativistic fields that was named relativistic canonical quantization (RCQ). I do not give here the full exact account of this scheme. But with the help of this review any physicist, even not a specialist in the relativistic quantum theory, will be able to get a general view of the content of RCQ, of its connection with other known approaches, of its novelty and of its fruitfulness.
Defense Science Board (DSB) Summer Study Report on Strategic Surprise
2015-07-01
DSB Summer Study Report on Strategic Surprise July 2015 Report Documentation Page Form ApprovedOMB No. 0704-0188 Public reporting burden...SUBTITLE DSB Summer Study Report on Strategic Surprise 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT...NUMBER 5e. TASK NUMBER 5f. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) Defense Science Board ( DSB ),The Pentagon ,OUSD(AT&L
Weibel Instability Growth Rate in Magnetized Plasmas with Quasi-Relativistic Distribution Function
Hosseini, Sayed Ahmad; Mahdavi, Mohammad
2016-12-01
The mechanism of the Weibel instability is investigated for dense magnetized plasmas. As we know, due to the electron velocity distribution, the Coulomb collision effect of electron-ion and the relativistic properties play an important role in such study. In this study an analytical expression for the growth rate and the condition of restricting the Weibel instability are derived for low-frequency limit. These calculations are done for the oscillation frequency dependence on the electron cyclotron frequency. It is shown that, the relativistic properties of the particle lead to increasing the growth rate of the instability. On the other hand the collision effects and background magnetic field try to decrease the growth rate by decreasing the temperature anisotropy and restricting the particles movement.
Simulating relativistic binaries with Whisky
Baiotti, L.
We report about our first tests and results in simulating the last phase of the coalescence and the merger of binary relativistic stars. The simulations were performed using our code Whisky and mesh refinement through the Carpet driver.
Relativistic effects in atom gravimeters
Tan, Yu-Jie; Shao, Cheng-Gang; Hu, Zhong-Kun
2017-01-01
Atom interferometry is currently developing rapidly, which is now reaching sufficient precision to motivate laboratory tests of general relativity. Thus, it is extremely significant to develop a general relativistic model for atom interferometers. In this paper, we mainly present an analytical derivation process and first give a complete vectorial expression for the relativistic interferometric phase shift in an atom interferometer. The dynamics of the interferometer are studied, where both the atoms and the light are treated relativistically. Then, an appropriate coordinate transformation for the light is performed crucially to simplify the calculation. In addition, the Bordé A B C D matrix combined with quantum mechanics and the "perturbation" approach are applied to make a methodical calculation for the total phase shift. Finally, we derive the relativistic phase shift kept up to a sensitivity of the acceleration ˜1 0-14 m/s 2 for a 10 -m -long atom interferometer.
Prater, R.; Farina, D.; Gribov, Y.; Harvey, R. W.; Ram, A. K.; Lin-Liu, Y. R.; Poli, E.; Smirnov, A. P.; Volpe, F.; Westerhof, E.; Zvonkovo, A.
2008-01-01
Optimal design and use of electron cyclotron heating requires that accurate and relatively quick computer codes be available for prediction of wave coupling, propagation, damping and current drive at realistic levels of EC power. To this end, a number of codes have been developed in laboratories wor
Scattering in Relativistic Particle Mechanics.
de Bievre, Stephan
The problem of direct interaction in relativistic particle mechanics has been extensively studied and a variety of models has been proposed avoiding the conclusions of the so-called no-interaction theorems. In this thesis we study scattering in the relativistic two-body problem. We use our results to analyse gauge invariance in Hamiltonian constraint models and the uniqueness of the symplectic structure in manifestly covariant relativistic particle mechanics. We first present a general geometric framework that underlies approaches to relativistic particle mechanics. This permits a model-independent and geometric definition of the notions of asymptotic completeness and of Moller and scattering operators. Subsequent analysis of these concepts divides into two parts. First, we study the kinematic properties of the scattering transformation, i.e. those properties that arise solely from the invariance of the theory under the Poincare group. We classify all canonical (symplectic) scattering transformations on the relativistic phase space for two free particles in terms of a single function of the two invariants of the theory. We show how this function is determined by the center of mass time delay and scattering angle and vice versa. The second part of our analysis of the relativistic two-body scattering problem is devoted to the dynamical properties of the scattering process. Hence, we turn to two approaches to relativistic particle mechanics: the Hamiltonian constraint models and the manifestly covariant formalism. Using general geometric arguments, we prove "gauge invariance" of the scattering transformation in the Todorov -Komar Hamiltonian constraint model. We conclude that the scattering cross sections of the Todorov-Komar models have the same angular dependence as their non-relativistic counterpart, irrespective of a choice of gauge. This limits the physical relevance of those models. We present a physically non -trivial Hamiltonian constraint model, starting from
Soliton propagation in relativistic hydrodynamics
Fogaça, D A; 10.1016/j.nuclphysa.2007.03.104
2013-01-01
We study the conditions for the formation and propagation of Korteweg-de Vries (KdV) solitons in nuclear matter. In a previous work we have derived a KdV equation from Euler and continuity equations in non-relativistic hydrodynamics. In the present contribution we extend our formalism to relativistic fluids. We present results for a given equation of state, which is based on quantum hadrodynamics (QHD).
Relativistic formulation and reference frame
Klioner, Sergei A.
2004-01-01
After a short review of experimental foundations of metric theories of gravity, the choice of general relativity as a theory to be used for the routine modeling of Gaia observations is justified. General principles of relativistic modeling of astronomical observations are then sketched and compared to the corresponding Newtonian principles. The fundamental reference system -- Barycentric Celestial Reference System, which has been chosen to be the relativistic reference system underlying the f...
Status of the Cyclotron Institute Upgrade Project
Melconian, Dan
2016-09-01
The Texas A&M University Re-accelerated EXotics (T-REX) project, an upgrade to the Cyclotron Institute, will provide high-quality re-accelerated secondary beams of a unique energy range and the ability to provide primary beams to two experiments concurrently. The upgrade is nearing completion of its three major tasks: re-commissioning of the existing K150 cyclotron; construction of light- and heavy-ion guide transport systems; and charge-boosting the K150 RIB for re-acceleration using the K500 cyclotron. The light-ion guide transport system will utilize the high intensity (>= 10 μ A) proton beam from the K150 to produce rare ions via fusion-evapouration reactions or proton-induced fission fragments. These ions will be transported to an ECR charge breeder prior to injection in the K500. The heavy-ion guide will use deep inelastic, transfer and fragmentation reactions using the up to 25 MeV/u primary beams from the K150. The products will be separated by a superconducting solenoid and collected in a large gas-catcher, after which a multi-RFQ system will transport the RIB to any of: the charge-breeder and K500; the TAMU Penning Trap beamline; or an MR-TOF for beam analysis. The status of the T-REX upgrade and an overview of its capabilities will be presented Supported by DOE Grant Number DE-FG03-93ER40773 and the Robert A. Welch Foundation Grant Number H-A-0098.
Pechhacker, Roman
2012-01-01
A beam of super-thermal, hot electrons was injected into maxwellian plasma with a density gradient along a magnetic field line. 1.5D particle-in-cell simulations were carried out which established that the EM emission is produced by the perpendicular component of the beam injection momentum. The beam has a positive slope in the distribution function in perpendicular momentum phase space, which is the characteristic feature of a cyclotron maser. The cyclotron maser in the overdense plasma generates emission at the electron cyclotron frequency. The frequencies of generated waves were too low to propagate away from the injection region, hence the wavelet transform shows a pulsating wave generation and decay process. The intensity pulsation frequency is twice the relativistic cyclotron frequency. Eventually, a stable wave packet formed and could mode couple on the density gradient to reach frequencies of the order of the plasma frequency, that allowed for propagation. The emitted wave is likely to be a z-mode wav...
Microwave Absorption in Electron Cyclotron Resonance Plasma
Institute of Scientific and Technical Information of China (English)
LIU Ming-Hai; HU Xi-Wei; WU Qin-Chong; YU Guo-Yang
2000-01-01
The microwave power absorption in electron cyclotron resonance plasma reactor was investigated with a twodimensional hybrid-code. Simulation results indicated that there are two typical power deposition profiles over the entire parameter region: (1) microwave power deposition peaks on the axis and decreases in radial direction,(2) microwave power deposition has its maximum at some radial position, i.e., a hollow distribution. The spatial distribution of electron temperature resembles always to the microwave power absorption profile. The dependence of plasma parameter on the gas pressure is discussed also.
Electron cyclotron emission diagnostics on KSTAR tokamak.
Jeong, S H; Lee, K D; Kogi, Y; Kawahata, K; Nagayama, Y; Mase, A; Kwon, M
2010-10-01
A new electron cyclotron emission (ECE) diagnostics system was installed for the Second Korea Superconducting Tokamak Advanced Research (KSTAR) campaign. The new ECE system consists of an ECE collecting optics system, an overmode circular corrugated waveguide system, and 48 channel heterodyne radiometer with the frequency range of 110-162 GHz. During the 2 T operation of the KSTAR tokamak, the electron temperatures as well as its radial profiles at the high field side were measured and sawtooth phenomena were also observed. We also discuss the effect of a window on in situ calibration.
Electron cyclotron emission diagnostics on KSTAR tokamak
Energy Technology Data Exchange (ETDEWEB)
Jeong, S. H. [Korea Atomic Energy Research Institute, 1045 Daedeokdaero, Daejeon 305-353 (Korea, Republic of); Lee, K. D.; Kwon, M. [National Fusion Research Institute, 113 Gwahangno, Daejeon 305-333 (Korea, Republic of); Kogi, Y. [Fukuoka Institute of Technology, Higashiku, Fukuoka 811-0295 (Japan); Kawahata, K.; Nagayama, Y. [National Institute for Fusion Science, Toki, Gifu 509-5292 (Japan); Mase, A. [KASTEC, Kyushu University, Kasuga, Fukuoka 816-8580 (Japan)
2010-10-15
A new electron cyclotron emission (ECE) diagnostics system was installed for the Second Korea Superconducting Tokamak Advanced Research (KSTAR) campaign. The new ECE system consists of an ECE collecting optics system, an overmode circular corrugated waveguide system, and 48 channel heterodyne radiometer with the frequency range of 110-162 GHz. During the 2 T operation of the KSTAR tokamak, the electron temperatures as well as its radial profiles at the high field side were measured and sawtooth phenomena were also observed. We also discuss the effect of a window on in situ calibration.
Electron Cyclotron Resonance Heating of a High-Density Plasma
DEFF Research Database (Denmark)
Hansen, F. Ramskov
1986-01-01
Various schemes for electron cyclotron resonance heating of tokamak plasmas with the ratio of electron plasma frequency to electron cyclotron frequency, "»pe/^ce* larger than 1 on axis, are investigated. In particular, a mode conversion scheme is investigated using ordinary waves at the fundamental...
The next generation of electron cyclotron emission imaging diagnostics (invited)
Zhang, P.; Domier, C.W.; Liang, T.; Kong, X.; Tobias, B.; Shen, Z.; N C Luhmann Jr.,; Park, H.; Classen, I.G.J.; van de Pol, M.J.; Donne, A. J. H.; R. Jaspers,
2008-01-01
A 128 channel two-dimensional electron cyclotron emission imaging system collects time-resolved 16x8 images of T-e profiles and fluctuations on the TEXTOR tokamak. Electron cyclotron emission imaging (ECEI) is undergoing significant changes which promise to revolutionize and extend its capabilities
The next generation of electron cyclotron emission imaging diagnostics (invited)
Zhang, P.; Domier, C.W.; Liang, T.; Kong, X.; Tobias, B.; Shen, Z.; N C Luhmann Jr.,; Park, H.; Classen, I.G.J.; van de Pol, M.J.; Donne, A. J. H.; R. Jaspers,
2008-01-01
A 128 channel two-dimensional electron cyclotron emission imaging system collects time-resolved 16x8 images of T-e profiles and fluctuations on the TEXTOR tokamak. Electron cyclotron emission imaging (ECEI) is undergoing significant changes which promise to revolutionize and extend its capabilities
A new generation of medical cyclotrons for the 90`s
Energy Technology Data Exchange (ETDEWEB)
Milton, B.F.
1995-08-01
Cyclotrons continue to be efficient accelerators for use in radio-isotope production. In recent years, developments in accelerator technology have greatly increased the practical beam current in these machines while also improving the overall system reliability. These developments combined with the development of new isotopes for medicine and industry, and a retiring of older machines indicates a strong future for commercial cyclotrons. In this paper the authors will survey recent developments in the areas of cyclotron technology as they relate to the new generation of commercial cyclotrons. Existing and potential markets for these cyclotrons will be presented. They will also discuss the possibility of systems capable of extracted energies up to 150 MeV and extracted beam currents of up to 2.0 mA.
Cyclotron resonance effects on stochastic acceleration of light ionospheric ions
Singh, N.; Schunk, R. W.; Sojka, J. J.
1982-01-01
The production of energetic ions with conical pitch angle distributions along the auroral field lines is a subject of considerable current interest. There are several theoretical treatments showing the acceleration (heating) of the ions by ion cyclotron waves. The quasi-linear theory predicts no acceleration when the ions are nonresonant. In the present investigation, it is demonstrated that the cyclotron resonances are not crucial for the transverse acceleration of ions by ion cyclotron waves. It is found that transverse energization of ionospheric ions, such as He(+), He(++), O(++), and O(+), is possible by an Electrostatic Hydrogen Cyclotron (EHC) wave even in the absence of cyclotron resonance. The mechanism of acceleration is the nonresonant stochastic heating. However, when there are resonant ions both the total energy gain and the number of accelerated ions increase with increasing parallel wave number.
Compression-amplified EMIC waves and their effects on relativistic electrons
Energy Technology Data Exchange (ETDEWEB)
Li, L. Y., E-mail: lyli-ssri@buaa.edu.cn; Yu, J.; Cao, J. B. [School of Space and Environment, Beihang University, Beijing (China); Yuan, Z. G. [School of Electronic Information, Wuhan University, Wuhan (China)
2016-06-15
During enhancement of solar wind dynamic pressure, we observe the periodic emissions of electromagnetic ion cyclotron (EMIC) waves near the nightside geosynchronous orbit (6.6R{sub E}). In the hydrogen and helium bands, the different polarized EMIC waves have different influences on relativistic electrons (>0.8 MeV). The flux of relativistic electrons is relatively stable if there are only the linearly polarized EMIC waves, but their flux decreases if the left-hand polarized (L-mode) EMIC waves are sufficiently amplified (power spectral density (PSD) ≥ 1 nT{sup 2}/Hz). The larger-amplitude L-mode waves can cause more electron losses. In contrast, the R-mode EMIC waves are very weak (PSD < 1 nT{sup 2}/Hz) during the electron flux dropouts; thus, their influence may be ignored here. During the electron flux dropouts, the relativistic electron precipitation is observed by POES satellite near the foot point (∼850 km) of the wave emission region. The quasi-linear simulation of wave-particle interactions indicates that the L-mode EMIC waves can cause the rapid precipitation loss of relativistic electrons, especially when the initial resonant electrons have a butterfly-like pitch angle distribution.
Beam Phase Measurements in the AGOR Cyclotron
Brandenburg, S; Van Asselt, W K
2003-01-01
Beamphase measurement to optimize the isochronism is an essential part of the diagnostics in multi-particle, multi-energy cyclotrons. In the AGOR cyclotron an array of 13 nondestructive beamphase pick-ups is installed. To reduce the large disturbances from the RF-system the measurements are traditionally performed at the 2nd harmonic of the RF-frequency. To further improve the sensitivity intensity modulation of the beam has been introduced. This creates side-bands in the Fourier spectrum, that are completely free of interference from the RF-system. These side-bands contain information on both the beamphase with respect to the accelerating voltage and the number of revolutions up to the radius of the measurement. A specific case is intensity modulation at the orbital frequency, where the side-bands contain only information on the beamphase. Measurements with the different methods will be presented, demonstrating that the intensity modulation strongly improves the sensitivity of the measurement. Useful beampha...
Status of the NSCL Cyclotron Gas Stopper
Joshi, N; Brodeur, M; Morrissey, D J; Schwarz, S
2016-01-01
A gas-filled reverse cyclotron for the thermalisation of energetic beams is under construction at NSCL/MSU. Rare isotopes produced via projectile fragmentation after in-flight separation will be injected into the device and converted into low-energy beams through buffer gas interactions as they spiral towards the centre of the device. The extracted thermal beams will be used for low energy experiments such as precision mass measurements with traps or laser spectroscopy, and further transport for reacceleration. Detailed calculations have been performed to optimize the magnetic field design as well as the transport and stopping of ions inside the gas. An RF carpet will be used to transport the thermal ions to the axial extraction point. The calculations indicate that the cyclotron gas stopper will be much more efficient for the thermalisation of light and medium mass ions compared to linear gas cells. In this contribution we will discuss simulations of the overall performance and acceptance of machine, the bea...
Cyclotron and linac production of Ac-225.
Melville, Graeme; Allen, Barry J
2009-04-01
Radium needles that were once implanted into tumours as a cancer treatment are now obsolete and constitute a radioactive waste problem, as their half-life is 1600 years. The reduction of radium by photonuclear transmutation by bombarding Ra-226 with high-energy photons from a medical linear accelerator (linac) has been investigated. A linac dose of 2800 Gy produced about 2.4 MBq (64 microCi) of Ra-225, which decays to Ac-225 and can then be used for 'Targeted Alpha Therapy' (TAT) of cancer. This result, while consistent with theoretical calculations, is far too low to be of practical use unless much larger quantities of radium are irradiated. The increasing application of Ac-225 for cancer therapy indicates the potential need for its increased production and availability. This paper investigates the possibility of producing of Ac-225 in commercial quantities, which could potentially reduce obsolete radioactive material and displace the need for expensive importation of Ac-225 from the USA and Russia in the years ahead. Scaled up production of Ac-225 could theoretically be achieved by the use of a high current cyclotron or linac. Production specifications are determined for a linac in terms of current, pulse length and frequency, as well as an examination of other factors such as radiation issues and radionuclei separation. Yields are compared with those calculated for the Australian National Cyclotron in Sydney.
Resonant cyclotron scattering in magnetars' emission
Rea, Nanda; Turolla, Roberto; Lyutikov, Maxim; Gotz, Diego
2008-01-01
We present a systematic application of a resonant cyclotron scattering (RCS) model to a comprehensive set of magnetars, including canonical and transient anomalous X-ray pulsars, and soft gamma repeaters. In this scenario, non-thermal magnetar spectra in the soft X-rays (i.e. below ~10keV) result from resonant cyclotron scattering of the thermal surface emission by hot magnetospheric plasma. We find that this model can successfully account for the X-ray emission of magnetars, while using the same number of free parameters than the commonly used empirical blackbody plus power-law model. We find that the entire class of sources is characterized by magnetospheric plasma with similar properties, in particular the optical depth is in a quite narrow range (tau_{res} ~1-2). This leads to an estimate of the magnetospheric electron densities at the resonance n_e ~ 1.5x10^{13} tau_{res} cm^{-3}, which is 3 orders of magnitudes greater than n_{GJ}, the Goldreich-Julian electron density for pulsar magnetospheres. The inf...
Refining a relativistic, hydrodynamic solver: Admitting ultra-relativistic flows
Bernstein, J. P.; Hughes, P. A.
2009-09-01
We have undertaken the simulation of hydrodynamic flows with bulk Lorentz factors in the range 102-106. We discuss the application of an existing relativistic, hydrodynamic primitive variable recovery algorithm to a study of pulsar winds, and, in particular, the refinement made to admit such ultra-relativistic flows. We show that an iterative quartic root finder breaks down for Lorentz factors above 102 and employ an analytic root finder as a solution. We find that the former, which is known to be robust for Lorentz factors up to at least 50, offers a 24% speed advantage. We demonstrate the existence of a simple diagnostic allowing for a hybrid primitives recovery algorithm that includes an automatic, real-time toggle between the iterative and analytical methods. We further determine the accuracy of the iterative and hybrid algorithms for a comprehensive selection of input parameters and demonstrate the latter’s capability to elucidate the internal structure of ultra-relativistic plasmas. In particular, we discuss simulations showing that the interaction of a light, ultra-relativistic pulsar wind with a slow, dense ambient medium can give rise to asymmetry reminiscent of the Guitar nebula leading to the formation of a relativistic backflow harboring a series of internal shockwaves. The shockwaves provide thermalized energy that is available for the continued inflation of the PWN bubble. In turn, the bubble enhances the asymmetry, thereby providing positive feedback to the backflow.
a Surprise from the Pulsar in the Crab Nebula
1995-11-01
classical atomic-line spectra. The matter is further complicated by the presence of a strong gravitational field near the surface of the pulsar which introduces a wavelength shift of an unknown size. This is the so called `gravitational redshift', a relativistic effect that may be observed in intense gravitational fields. The size of the wavelength shift is proportionate, at least to a first approximation, to the strength of the gravitational field to which the emitting atoms are subjected. But the strength of the pulsar's gravitational field decreases with the altitude above the surface and as we do not know at which altitude the ions that produce the observed `dip' are located, the induced shift is of unknown size. The presence of this feature is an unexpected bonus for the study of the physics of neutron stars. Following a preliminary investigation of the possible causes, the astronomers are now of the opinion that it may have to do with light being absorbed due to the peculiar motion of atoms in the superintense magnetic field around the pulsar [4]. To cast more light on this problem, the group is now planning to obtain spectroscopic observations with an even higher spectral resolution. If not before, this will in any case become possible when the first 8.2-metre VLT Unit Telescope enters into operation in about two years' time. Notes: [1] The group consists of Giovanni Bignami, Patrizia Caraveo, Roberto Mignani and Francesco Nasuti from Istituto di Fisica Cosmica e Tecnologie Relative in Milan, Italy. [2] Named after Franco Pacini, Director of the Florence observatory and former President of the ESO Council. [3] Much of this work is due to Lodewijk Woltjer, a Dutch astronomer, who was ESO Director General from 1975 to 1987. [4] However, better data are needed to understand the nature of the absorption. While Iron has some lines in this spectral range, it could as well be cyclotron absorption for Hydrogen.
Roles of Fast-Cyclotron and Alfven-Cyclotron Waves for the Multi-Ion Solar Wind
Xiong, Ming
2012-01-01
Using linear Vlasov theory of plasma waves and quasi-linear theory of resonant wave-particle interaction, the dispersion relations and the electromagnetic field fluctuations of fast and Alfven waves are studied for a low-beta multi-ion plasma in the inner corona. Their probable roles in heating and accelerating the solar wind via Landau and cyclotron resonances are quantified. We assume that (1) low-frequency Alfven and fast waves have the same spectral shape and the same amplitude of power spectral density; (2) these waves eventually reach ion cyclotron frequencies due to a turbulence cascade; (3) kinetic wave-particle interaction powers the solar wind. The existence of alpha particles in a dominant proton/electron plasma can trigger linear mode conversion between oblique fast-whistler and hybrid alpha-proton cyclotron waves. The fast-cyclotron waves undergo both alpha and proton cyclotron resonances. The alpha cyclotron resonance in fast-cyclotron waves is much stronger than that in Alfven-cyclotron waves. ...
Cyclotron Production of Technetium-99m
Gagnon, Katherine M.
Technetium-99m (99mTc) has emerged as the most widely used radionuclide in medicine and is currently obtained from a 99Mo/ 99mTc generator system. At present, there are only a handful of ageing reactors worldwide capable of producing large quantities of the parent isotope, 99Mo, and owing to the ever growing shutdown periods for maintenance and repair of these ageing reactors, the reliable supply 99mTc has been compromised in recent years. With an interest in alternative strategies for producing this key medical isotope, this thesis focuses on several technical challenges related to the direct cyclotron production of 99mTc via the 100Mo(p,2n)99mTc reaction. In addition to evaluating the 100Mo(p,2n)99mTc and 100Mo(p,x)99Mo reactions, this work presented the first experimental evaluation of the 100Mo(p,2n) 99gTc excitation function in the range of 8-18 MeV. Thick target calculations suggested that large quantities of cyclotron-produced 99mTc may be possible. For example, a 6 hr irradiation at 500 μA with an energy window of 18→10 MeV is expected to yield 1.15 TBq of 99mTc. The level of coproduced 99gTc contaminant was found to be on par with the current 99Mo/99mTc generator standard eluted with a 24 hr frequency. Highly enriched 100Mo was required as the target material for 99mTc production and a process for recycling of this expensive material is presented. An 87% recovery yield is reported, including metallic target preparation, irradiation, 99mTc extraction, molybdate isolation, and finally hydrogen reduction to the metal. Further improvements are expected with additional optimization experiments. A method for forming structurally stable metallic molybdenum targets has also been developed. These targets are capable of withstanding more than a kilowatt of beam power and the reliable production and extraction of Curie quantities of 99mTc has been demonstrated. With the end-goal of using the cyclotron-produced 99mTc clinically, the quality of the cyclotron
Empirical Foundations of Relativistic Gravity
Ni, W T
2005-01-01
In 1859, Le Verrier discovered the mercury perihelion advance anomaly. This anomaly turned out to be the first relativistic-gravity effect observed. During the 141 years to 2000, the precisions of laboratory and space experiments, and astrophysical and cosmological observations on relativistic gravity have been improved by 3 orders of magnitude. In 1999, we envisaged a 3-6 order improvement in the next 30 years in all directions of tests of relativistic gravity. In 2000, the interferometric gravitational wave detectors began their runs to accumulate data. In 2003, the measurement of relativistic Shapiro time-delay of the Cassini spacecraft determined the relativistic-gravity parameter gammaγ with a 1.5-order improvement. In October 2004, Ciufolini and Pavlis reported a measurement of the Lense-Thirring effect on the LAGEOS and LAGEOS2 satellites to 10 percent of the value predicted by general relativity. In April 2004, Gravity Probe B was launched and has been accumulating science data for more than ...
Avoiding surprises when implementing a single quality system.
Donawa, Maria
2009-01-01
European medical device manufacturers are sometimes surprised to learn that operating ISO 13485 alone is not sufficient to meet United States (US) quality system requirements. This article discusses important considerations for meeting US and European requirements when operating under a single quality system.
Reconsiderations: Donald Murray and the Pedagogy of Surprise
Ballenger, Bruce
2008-01-01
Toward the end of his life, Donald Murray felt that his approach to writing instruction was no longer appreciated by journals in his field. Nevertheless, his emphasis on encouraging students to surprise themselves through informal writing still has considerable value. (Contains 1 note.)
Reconsiderations: Donald Murray and the Pedagogy of Surprise
Ballenger, Bruce
2008-01-01
Toward the end of his life, Donald Murray felt that his approach to writing instruction was no longer appreciated by journals in his field. Nevertheless, his emphasis on encouraging students to surprise themselves through informal writing still has considerable value. (Contains 1 note.)
Errors and surprise in patients with focal brain lesions
Ullsperger, M.
2016-01-01
Recent theories of performance monitoring suggest that not only errors and negative action outcomes but also valence-free expectancy violations can trigger cognitive and behavioral adaptations. EEG and fMRI evidence suggests that monitoring of both errors and surprising but valence-free action
Electromagnetic ion cyclotron waves observed near the oxygen cyclotron frequency by ISEE 1 and 2
Fraser, B. J.; Samson, J. C.; Hu, Y. D.; Mcpherron, R. L.; Russell, C. T.
1992-01-01
The first results of observations of ion cyclotron waves by the elliptically orbiting ISEE 1 and 2 pair of spacecraft are reported. The most intense waves (8 nT) were observed in the outer plasmasphere where convection drift velocities were largest and the Alfven velocity was a minimum. Wave polarization is predominantly left-handed with propagation almost parallel to the ambient magnetic field, and the spectral slot and polarization reversal predicted by cold plasma propagation theory are identified in the wave data. Computations of the experimental wave spectra during the passage through the plasmapause show that the spectral slots relate to the local plasma parameters, possibly suggesting an ion cyclotron wave growth source near the spacecraft. A regular wave packet structure seen over the first 30 min of the event is attributed to the modulation of this energy source by the Pc 5 waves seen at the same time.
Cyclotrons and positron emission tomography radiopharmaceuticals for clinical imaging.
Saha, G B; MacIntyre, W J; Go, R T
1992-07-01
Positron emission tomography (PET) requires positron-emitting radionuclides that emit 511-keV photons detectable by PET imagers. Positron-emitting radionuclides are commonly produced in charged particle accelerators, eg, linear accelerators or cyclotrons. The most widely available radiopharmaceuticals for PET imaging are carbon-11-, nitrogen-13-, and oxygen-15-labeled compounds, many of which, either in their normal state or incorporated in other compounds, serve as physiological tracers. Other useful PET radiopharmaceuticals include fluorine-18-, bromine-75-, gallium-68 (68Ga)-, rubidium-82 (82Rb)-, and copper-62 (62Cu)-labeled compounds. Many positron emitters have short half-lives and thus require on-site cyclotrons for application, and others (68Ga, 82Rb, and 62Cu) are available from radionuclides generators using relatively long-lived parent radionuclides. This review is divided into two sections: cyclotrons and PET radiopharmaceuticals for clinical imaging. In the cyclotron section, the principle of operation of the cyclotron, types of cyclotrons, medical cyclotrons, and production of radionuclides are discussed. In the section on PET radiopharmaceuticals, the synthesis and clinical use of PET radiopharmaceuticals are described.
Relativistic causality and clockless circuits
Matherat, Philippe; 10.1145/2043643.2043650
2011-01-01
Time plays a crucial role in the performance of computing systems. The accurate modelling of logical devices, and of their physical implementations, requires an appropriate representation of time and of all properties that depend on this notion. The need for a proper model, particularly acute in the design of clockless delay-insensitive (DI) circuits, leads one to reconsider the classical descriptions of time and of the resulting order and causal relations satisfied by logical operations. This questioning meets the criticisms of classical spacetime formulated by Einstein when founding relativity theory and is answered by relativistic conceptions of time and causality. Applying this approach to clockless circuits and considering the trace formalism, we rewrite Udding's rules which characterize communications between DI components. We exhibit their intrinsic relation with relativistic causality. For that purpose, we introduce relativistic generalizations of traces, called R-traces, which provide a pertinent des...
Surprising results from abiotic enzyme digestion of dissolved organic matter at the molecular scale
Hess, N. J.; Tfaily, M. M.; Heredia-Langnar, A.; Rodriguez, L.; Purvine, E.; Todd-Brown, K. E.
2016-12-01
Sometimes even the simplest of experiments leads to unexpected results and new understanding. We extract dissolved organic matter using water from peat soil obtained from the S1 bog at the Marcell Experimental Forest in northern Minnesota. We characterized the dissolved organic matter in the water extract before and after adding glucosidase, peroxidase and β-N-Acetylglucosaminidase enzymes using electrospray Fourier transform ion cyclotron resonance mass spectrometry in negative ion mode. Based on mass measurement accuracy of less than 1 ppm for singly charged ions, we assigned putative chemical formula to greater than 80% of the measured mass spectrometry features. For each enzyme tested we are able to easily distinguish between the types and composition of dissolved organic molecules that are susceptible to enzyme degradation - and those that are not - based on the presence new compounds in reacted extracts and loss of compounds from the initial water extract. Next, we created a consensus molecular network analysis based on the neutral mass loss between the measured compounds for each enzyme. The connectivity within these networks suggested a unique, distinctive chemistry for each enzyme. Some results were expected, like the nondiscriminatory oxidation of organic molecules by peroxidase and preferential loss of lignin and tannin-like molecules by glucosidase. However, surprising results include the apparent reactivity of glucosidase enzymatic products to reassemble, forming larger mass organic molecules. While these experiments were conducted abiotically, these molecular-resolved results suggest that biotic enzymatic processes may result in product compounds with unexpected chemistry and reactivity, implying that our current conceptual model of microbial enzymatic activity may be overly simplistic.
On the nonuniqueness of free motion of the fundamental relativistic rotator
Bratek, Łukasz
2009-01-01
Consider a class of relativistic rotators described by position and a single null direction. Such a rotator is called fundamental if both its Casimir invariants are intrinsic dimensional parameters independent of arbitrary constants of motion. As shown by Staruszkiewicz, only one rotator with this property exists (its partner with similar property can be excluded on physical grounds). We obtain a general solution to equations of free motion of the fundamental relativistic rotator in a covariant manner. Surprisingly, this motion is not entirely determined by initial conditions but depends on one arbitrary function of time, which specifies rotation of the null direction in the centre of momentum frame. This arbitrariness is in manifest contradiction with classical determinism. In this sense the isolated fundamental relativistic rotator is pathological as a dynamical system. To understand why this is so, we study the necessary condition for the uniqueness of the related Cauchy problem. It turns out that the fund...
Ion cyclotron emission by spontaneous emission
Energy Technology Data Exchange (ETDEWEB)
Da Costa, O. [Commission of the European Communities, Abingdon (United Kingdom). JET Joint Undertaking; Gresillon, D. [Ecole Polytechnique, 91 - Palaiseau (France). Lab. de Physique des Milieux Ionises
1994-07-01
The goal of the study is to examine whether the spontaneous emission can account for ICE (ion cyclotron emission) experimental results, or part of them. A straightforward approach to plasma emission is chosen, investigating the near equilibrium wave radiation by gyrating ions, and thus building from the majority and fast fusion ions the plasma fluctuations and emission on the fast magnetoacoustic or compressional Alfven wave mode in the IC frequency range. Similarities with the ICE experiments are shown: the emission temperature in the presence of fast ions (even in a very small amount), the strong fast ion emission increase with the harmonic, the fine double-line splitting of each peak, the linear but not proportional increase of the peak width with the harmonic. 3 refs., 2 figs.
Simulation of cyclotron resonant scattering features
Directory of Open Access Journals (Sweden)
Schwarm Fritz-Walter
2014-01-01
Full Text Available X-ray binary systems consisting of a mass donating optical star and a highly magnetized neutron star, under the right circumstances, show quantum mechanical absorption features in the observed spectra called cyclotron resonant scattering features (CRSFs. We have developed a simulation to model CRSFs using Monte Carlo methods. We calculate Green’s tables which can be used to imprint CRSFs to arbitrary X-ray continua. Our simulation keeps track of scattering parameters of individual photons, extends the number of variable parameters of previous works, and allows for more flexible geometries. Here we focus on the influence of bulk velocity of the accreted matter on the CRSF line shapes and positions.
Ion cyclotron resonance heating system on Aditya
Indian Academy of Sciences (India)
D Bora; Sunil Kumar; Raj Singh; S V Kulkarni; A Mukherjee; J P Singh; Raguraj Singh; S Dani; A Patel; Sai Kumar; V George; Y S S Srinivas; P Khilar; M Kushwah; P Shah; H M Jadav; Rajnish Kumar; S Gangopadhyay; H Machhar; B Kadia; K Parmar; A Bhardwaj; Suresh Adav; D Rathi; D S Bhattacharya
2005-02-01
An ion cyclotron resonance heating (ICRH) system has been designed, fabricated indigenously and commissioned on Tokamak Aditya. The system has been commissioned to operate between 20·0 and 47·0 MHz at a maximum power of 200 kW continuous wave (CW). Duration of 500 ms is sufﬁcient for operation on Aditya, however, the same system feeds the ﬁnal stage of the 1·5 MW ICRH system being prepared for the steady-state superconducting tokamak (SST-1) for a duration of 1000 s. Radio frequency (RF) power (225 kW) has been generated and successfully tested on a dummy load for 100s at 30·0 MHz. Lower powers have been coupled to Aditya in a breakdown experiment. We describe the system in detail in this work.
Relativistic RPA in axial symmetry
Arteaga, D Pena; 10.1103/PhysRevC.77.034317
2009-01-01
Covariant density functional theory, in the framework of self-consistent Relativistic Mean Field (RMF) and Relativistic Random Phase approximation (RPA), is for the first time applied to axially deformed nuclei. The fully self-consistent RMF+RRPA equations are posed for the case of axial symmetry and non-linear energy functionals, and solved with the help of a new parallel code. Formal properties of RPA theory are studied and special care is taken in order to validate the proper decoupling of spurious modes and their influence on the physical response. Sample applications to the magnetic and electric dipole transitions in $^{20}$Ne are presented and analyzed.
Multifragmentation calculated with relativistic forces
Feldmeier, H; Papp, G
1995-01-01
A saturating hamiltonian is presented in a relativistically covariant formalism. The interaction is described by scalar and vector mesons, with coupling strengths adjusted to the nuclear matter. No explicit density depe ndence is assumed. The hamiltonian is applied in a QMD calculation to determine the fragment distribution in O + Br collision at different energies (50 -- 200 MeV/u) to test the applicability of the model at low energies. The results are compared with experiment and with previous non-relativistic calculations. PACS: 25.70Mn, 25.75.+r
Relativistic Stern-Gerlach Deflection
Talman, Richard
2016-01-01
Modern advances in polarized beam control should make it possible to accurately measure Stern-Gerlach (S-G) deflection of relativistic beams. Toward this end a relativistically covariant S-G formalism is developed that respects the opposite behavior under inversion of electric and magnetic fields. Not at all radical, or even new, this introduces a distinction between electric and magnetic fields that is not otherwise present in pure Maxwell theory. Experimental configurations (mainly using polarized electron beams passing through magnetic or electric quadrupoles) are described. Electron beam preparation and experimental methods needed to detect the extremely small deflections are discussed.
Special Relativistic Hydrodynamics with Gravitation
Hwang, Jai-chan; Noh, Hyerim
2016-12-01
Special relativistic hydrodynamics with weak gravity has hitherto been unknown in the literature. Whether such an asymmetric combination is possible has been unclear. Here, the hydrodynamic equations with Poisson-type gravity, considering fully relativistic velocity and pressure under the weak gravity and the action-at-a-distance limit, are consistently derived from Einstein’s theory of general relativity. An analysis is made in the maximal slicing, where the Poisson’s equation becomes much simpler than our previous study in the zero-shear gauge. Also presented is the hydrodynamic equations in the first post-Newtonian approximation, now under the general hypersurface condition. Our formulation includes the anisotropic stress.
Special relativistic hydrodynamics with gravitation
Hwang, Jai-chan
2016-01-01
The special relativistic hydrodynamics with weak gravity is hitherto unknown in the literature. Whether such an asymmetric combination is possible was unclear. Here, the hydrodynamic equations with Poisson-type gravity considering fully relativistic velocity and pressure under the weak gravity and the action-at-a-distance limit are consistently derived from Einstein's general relativity. Analysis is made in the maximal slicing where the Poisson's equation becomes much simpler than our previous study in the zero-shear gauge. Also presented is the hydrodynamic equations in the first post-Newtonian approximation, now under the {\\it general} hypersurface condition. Our formulation includes the anisotropic stress.
Vector Theory in Relativistic Thermodynamics
Institute of Scientific and Technical Information of China (English)
刘泽文
1994-01-01
It is pointed out that five defects occur in Planck-Einstein’s relativistic thermodynamics (P-E theory). A vector theory in relativistic thermodynamics (VTRT) is established. Defining the internal energy as a 4-vector, and supposing the entropy and the number of. particles to be invariants we have derived the transformations of all quantities, and subsequently got the Lagrangian and 4-D forms of thermodynamic laws. In order to test the new theory, several exact solutions with classical limits are given. The VTRT is free from the defects of the P-E theory.
Frontiers in relativistic celestial mechanics
2014-01-01
Relativistic celestial mechanics – investigating the motion celestial bodies under the influence of general relativity – is a major tool of modern experimental gravitational physics. With a wide range of prominent authors from the field, this two-volume series consists of reviews on a multitude of advanced topics in the area of relativistic celestial mechanics – starting from more classical topics such as the regime of asymptotically-flat spacetime, light propagation and celestial ephemerides, but also including its role in cosmology and alternative theories of gravity as well as modern experiments in this area.
ECR Ion Source for a High-Brightness Cyclotron
Comeaux, Justin; McIntyre, Peter; Assadi, Saeed
2011-10-01
New technology is being developed for high-brightness, high-current cyclotrons with performance benefits for accelerator-driven subcritical fission power, medical isotope production, and proton beam cancer therapy. This paper describes the design for a 65 kV electron cyclotron resonance (ECR) ion source that will provide high-brightness beam for injection into the cyclotron. The ion source is modeled closely upon the one that is used at the Paul Scherrer Institute. Modifications are being made to provide enhanced brightness and compatibility for higher-current operation.
Improving cancer treatment with cyclotron produced radionuclides. Progress report
Energy Technology Data Exchange (ETDEWEB)
Larson, S.M.; Finn, R.D.
1993-11-01
This report describes our continuing long term goal of promoting nuclear medicine applications by improving the scientific basis for tumor diagnosis, treatment and treatment follow-up based on the use of cyclotron produced radiotracers in oncology. The program includes 3 interactive components: Radiochemistry/Cyclotron; Pharmacology; and Immunology. An essential strategy is as follows: novel radionuclides and radiotracers developed in the Radiochemistry/Cyclotron section will be employed in the Pharmacology and Immunology sections during the next year. The development of novel radionuclides and tracers is of course useful in and of itself, but their utility is greatly enhanced by the interaction with the immunology and pharmacology components of the program.
Accelerators for hadrontherapy: From Lawrence cyclotrons to linacs
Amaldi, U.; Bonomi, R.; Braccini, S.; Crescenti, M.; Degiovanni, A.; Garlasché, M.; Garonna, A.; Magrin, G.; Mellace, C.; Pearce, P.; Pittà, G.; Puggioni, P.; Rosso, E.; Verdú Andrés, S.; Wegner, R.; Weiss, M.; Zennaro, R.
2010-08-01
Hadrontherapy with protons and carbon ions is a fast developing methodology in radiation oncology. The accelerators used and planned for this purpose are reviewed starting from the cyclotrons used in the thirties. As discussed in the first part of this paper, normal and superconducting cyclotrons are still employed, together with synchrotrons, for proton therapy while for carbon ion therapy synchrotrons have been till now the only option. The latest developments concern a superconducting cyclotron for carbon ion therapy, fast-cycling high frequency linacs and 'single room' proton therapy facilities. These issues are discussed in the second part of the paper by underlining the present challenges, in particular the treatment of moving organs.
Radiation Monitoring System of 30 MeV Cyclotron
Lee, Jin-Woo; Hur, Min-Goo; Jeong, Gyosung; Kim, Jongil
2017-09-01
A state-of-the-art radiation monitoring system was implemented at KAERI for a 30-MeV cyclotron. This system consists of several types of radiation measuring systems for ambient dose equivalent rate measurements of outside photon and neutron areas as well as inside the cyclotron, and monitors the alpha and beta particulates released from a stack, as well as the results of worker contamination at the portal of the cyclotron. In addition, an automatic alarm system is also mounted if there are alarms in the measuring systems.
High-current cyclotron to drive an electronuclear assembly
Alenitsky, Yu G
2002-01-01
The proposal on creation of a high-current cyclotron complex for driving an electronuclear assembly reported at the 17th Meeting on Accelerators of Charged Particles is discussed. Some changes in the basic design parameters of the accelerator are considered in view of new results obtained in the recent works. It is shown that the cyclotron complex is now the most real and cheapest accelerator for production of proton beams with a power of up to 10 MW. Projects on design of a high-current cyclotron complex for driving an electronuclear subcritical assembly are presented.
Global Simulation of Electromagnetic Ion Cyclotron Waves
Khazanov, George V.; Gallagher, D. L.; Kozyra, J. U.
2007-01-01
It is very well known that the effects of electromagnetic ion cyclotron (EMIC) waves on ring current (RC) ion and radiation belt (RB) electron dynamics strongly depend on such particle/wave characteristics as the phase-space distribution function, frequency, wave-normal angle, wave energy, and the form of wave spectral energy density. The consequence is that accurate modeling of EMIC waves and RC particles requires robust inclusion of the interdependent dynamics of wave growth/damping, wave propagation, and particles. Such a self-consistent model is being progressively developed by Khazanov et al. This model is based on a system of coupled kinetic equations for the RC and EMIC wave power spectral density along with the ray tracing equations. We will discuss the recent progress in understanding EMIC waves formation mechanisms in the inner magnetosphere. This problem remains unsettled in spite of many years of experimental and theoretical studies. Modern satellite observations by CRRES, Polar and Cluster still do not reveal the whole picture experimentally since they do not stay long enough in the generation region to give a full account of all the spatio-temporal structure of EMIC waves. The complete self-consistent theory taking into account all factors significant for EMIC waves generation remains to be developed. Several mechanisms are discussed with respect to formation of EMIC waves, among them are nonlinear modification of the ionospheric reflection by precipitating energetic protons, modulation of ion-cyclotron instability by long-period (Pc3/4) pulsations, reflection of waves from layers of heavy-ion gyroresonances, and nonlinearities of wave generation process. We show that each of these mechanisms have their attractive features and explains certain part experimental data but any of them, if taken alone, meets some difficulties when compared to observations. We conclude that development of a refined nonlinear theory and further correlated analysis of modern
Relativistic Hydrodynamics for Heavy-Ion Collisions
Ollitrault, Jean-Yves
2008-01-01
Relativistic hydrodynamics is essential to our current understanding of nucleus-nucleus collisions at ultrarelativistic energies (current experiments at the Relativistic Heavy Ion Collider, forthcoming experiments at the CERN Large Hadron Collider). This is an introduction to relativistic hydrodynamics for graduate students. It includes a detailed…
Sleeping beauties in theoretical physics 26 surprising insights
Padmanabhan, Thanu
2015-01-01
This book addresses a fascinating set of questions in theoretical physics which will both entertain and enlighten all students, teachers and researchers and other physics aficionados. These range from Newtonian mechanics to quantum field theory and cover several puzzling issues that do not appear in standard textbooks. Some topics cover conceptual conundrums, the solutions to which lead to surprising insights; some correct popular misconceptions in the textbook discussion of certain topics; others illustrate deep connections between apparently unconnected domains of theoretical physics; and a few provide remarkably simple derivations of results which are not often appreciated. The connoisseur of theoretical physics will enjoy a feast of pleasant surprises skilfully prepared by an internationally acclaimed theoretical physicist. Each topic is introduced with proper background discussion and special effort is taken to make the discussion self-contained, clear and comprehensible to anyone with an undergraduate e...
The June surprises: balls, strikes, and the fog of war.
Fried, Charles
2013-04-01
At first, few constitutional experts took seriously the argument that the Patient Protection and Affordable Care Act exceeded Congress's power under the commerce clause. The highly political opinions of two federal district judges - carefully chosen by challenging plaintiffs - of no particular distinction did not shake that confidence that the act was constitutional. This disdain for the challengers' arguments was only confirmed when the act was upheld by two highly respected conservative court of appeals judges in two separate circuits. But after the hostile, even mocking questioning of the government's advocate in the Supreme Court by the five Republican-appointed justices, the expectation was that the act would indeed be struck down on that ground. So it came as no surprise when the five opined the act did indeed exceed Congress's commerce clause power. But it came as a great surprise when Chief Justice John Roberts, joined by the four Democrat-appointed justices, ruled that the act could be sustained as an exercise of Congress's taxing power - a ground urged by the government almost as an afterthought. It was further surprising, even shocking, that Justices Antonin Scalia, Anthony Kennedy, Clarence Thomas, and Samuel Alito not only wrote a joint opinion on the commerce clause virtually identical to that of their chief, but that in writing it they did not refer to or even acknowledge his opinion. Finally surprising was the fact that Justices Ruth Bader Ginsburg and Stephen Breyer joined the chief in holding that aspects of the act's Medicaid expansion were unconstitutional. This essay ponders and tries to unravel some of these puzzles.
Microscopic Processes in Relativistic Jets
Nishikawa, K.-I.; Hardee, P.; Mizuno, Y.; Medvedev, M.; Zhang, B.; Nordlund, A.; Fredricksen, J.; Sol, H.; Niemiec, J.; Lyubarsky, Y.;
2008-01-01
Nonthermal radiation observed from astrophysical systems containing relativistic jets and shocks, e.g., gamma-ray bursts (GRBs), active galactic nuclei (AGNs), and Galactic microquasar systems usually have power-law emission spectra. Recent PIC simulations of relativistic electron-ion (electro-positron) jets injected into a stationary medium show that particle acceleration occurs within the downstream jet. In the collisionless relativistic shock particle acceleration is due to plasma waves and their associated instabilities (e.g., the Buneman instability, other two-streaming instability, and the Weibel (filamentation) instability) created in the shocks are responsible for particle (electron, positron, and ion) acceleration. The simulation results show that the Weibel instability is responsible for generating and amplifying highly nonuniform, small-scale magnetic fields. These magnetic fields contribute to the electron's transverse deflection behind the jet head. The 'jitter' radiation from deflected electrons has different properties than synchrotron radiation which is calculated in a uniform magnetic field. This jitter radiation may be important to understanding the complex time evolution and/or spectral structure in gamma-ray bursts, relativistic jets, and supernova remnants.
The Highest Redshift Relativistic Jets
Energy Technology Data Exchange (ETDEWEB)
Cheung, C.C.; Stawarz, L.; Siemiginowska, A.; Harris, D.E; Schwartz, D.A.; Wardle, J.F.C.; Gobeille, D.; Lee, N.P.
2007-12-18
We describe our efforts to understand large-scale (10's-100's kpc) relativistic jet systems through observations of the highest-redshift quasars. Results from a VLA survey search for radio jets in {approx} 30 z > 3.4 quasars are described along with new Chandra observations of 4 selected targets.
Circular polarization in relativistic jets
Macquart, JP
2003-01-01
Circular polarization is observed in some relativistic jet sources at radio wavelengths. It is largely associated with activity in the cores of the radio sources, is highly variable, and is strongest during ejection episodes. VLBI imaging and interstellar scintillation arguments show that the degree
Cyclotron mode frequency shifts in multi-species ion plasmas
Energy Technology Data Exchange (ETDEWEB)
Affolter, M.; Anderegg, F.; Dubin, D.H.E.; Driscoll, C.F.
2014-06-27
In trapped plasmas, electric fields and collective effects shift the cyclotron mode frequencies away from the “bare” cyclotron frequency for each species s. Here, these shifts are measured on a set of cyclotron modes (m=0,1, and 2) with cos(mθ) azimuthal dependence in near rigid-rotor multi-species ion plasmas. We observe that these frequency shifts are dependent on the plasma density, through the E×B rotation frequency f{sub E}, and on the “local” charge concentration δ{sub s} of species s, in close agreement with theory. - Highlights: • Cyclotron modes varying as sin(mθ) with m=0,1and2 are detected. • These mode frequencies shift by factors of the ExB rotation frequency. • These frequency shifts depend on the species charge fraction and radial distribution. • Centrifugal separation of species can greatly modify these frequency shifts.
Variable-Energy Cyclotron for Proton Therapy Application
Alenitsky, Yu G; Vorozhtsov, A S; Glazov, A A; Mytsyn, G V; Molokanov, A G; Onishchenko, L M
2004-01-01
The requirements to characteristics of the beams used for proton therapy are considered. The operation and proposed cyclotrons for proton therapy are briefly described. The technical decisions of creation of the cyclotron with energy variation in the range 70-230 MeV and with current up to 100 nA are estimated. Taking into account the fact, that the size and cost of the cyclotron are approximately determined by the maximum proton energy, it is realistically offered to limit the maximum proton energy to 190 MeV and to elaborate a cyclotron project with a warm winding of the magnet for acceleration of H^{-} ions. The energy of the extracted protons for each run is determined by a stripped target radius in the vacuum chamber of the accelerator, and the radiation dose field for the patient is created by the external devices using the developed techniques.
Cryogenic system for VECC K500 superconducting cyclotron
Pal, G; Bhattacharyya, T K; Bhandari, R K
2009-01-01
VEC Centre, Kolkata in India is at an advanced stage of commissioning a K500 superconducting cyclotron. The superconducting coil of the magnet for cyclotron is cooled by liquid helium. Three liquid helium cooled cryopanels, placed inside the Dees of the radiofrequency system, maintain the vacuum in the acceleration region of the superconducting cyclotron. The cryogenic system for magnet for cyclotron has been tested by cooling the coil and energizing the magnet. The cryogenic system for cryopanels has also been tested. Heater and temperature sensor were placed on the liquid helium cold head for cryopanel. The temperature of the cold head was observed to be below 20 K upto a heat load of 11.7 watt.
Design Study Of Cyclotron Magnet With Permanent Magnet
Kim, Hyun Wook; Chai, Jong Seo
2011-06-01
Low energy cyclotrons for Positron emission tomography (PET) have been wanted for the production of radio-isotopes after 2002. In the low energy cyclotron magnet design, increase of magnetic field between the poles is needed to make a smaller size of magnet and decrease power consumption. The Permanent magnet can support this work without additional electric power consumption in the cyclotron. In this paper the study of cyclotron magnet design using permanent magnet is shown and also the comparison between normal magnet and the magnet which is designed with permanent magnet is shown. Maximum energy of proton is 8 MeV and RF frequency is 79.3 MHz. 3D CAD design was done by CATIA P3 V5 R18 [1] and the All field calculations had been performed by OPERA-3D TOSCA [2]. The self-made beam dynamics program OPTICY [3] is used for making isochronous field and other calculations.
Undergraduate Education with the Rutgers 12-Inch Cyclotron
Koeth, Timothy W.
The Rutgers 12-Inch Cyclotron is a research grade accelerator dedicated to undergraduate education. From its inception, it has been intended for instruction and has been designed to demonstrate classic beam physics phenomena and provides students hands on experience with accelerator technology. The cyclotron is easily reconfigured, allowing experiments to be designed and performed within one academic semester. Our cyclotron offers students the opportunity to operate an accelerator and directly observe many fundamental beam physics concepts, including axial and radial betatron motion, destructive resonances, weak and azimuthally varying field (AVF) focusing schemes, RF and DEE voltage effects, diagnostic techniques, and perform low energy nuclear reactions. This paper emphasizes the unique beam physics measurements and beam manipulations capable at the Rutgers 12-Inch Cyclotron.
The fundamental cyclotron line in 4U 1538-52
Rodes-Roca, J J; Bernabéu, J G
2009-01-01
We present pulse phase averaged spectra of the high mass X-ray binary pulsar 4U 1538-52/QV Nor. Observations of this persistent accreting pulsar were made with the Rossi X-ray Timing Explorer (RXTE). We study the variability of cyclotron resonant scattering feature (CRSF or simply cyclotron line) in the high energy spectra of this binary system. We show that the parameters of the CRSF are correlated. The first one is, as suggested by theory, between the width and the energy of the cyclotron line. The second one is between the relative width and the optical depth of the cyclotron line. We discuss these results with studies of other X-ray pulsars and their implications on the line variability.
Design of 10 MeV cyclotron accelerator
Directory of Open Access Journals (Sweden)
R Solhju
2015-09-01
Full Text Available Design and construction of 10MeV cyclotron has been started at Amirkabir University of Technology since 2012. So far, the conceptual and detail engineering design phases have been finalized. The main purpose of this baby cyclotron is to generate proton beam for the production of PET radioisotopes. The cyclotron consists of magnet, cavity, ion source, RF and LLRF system, vacuum system, cooling system, power amplifiers and power supplies system. In this paper, a brief of design principles for all the parts of cyclotron and their final simulation results is presented. It should be noted that these simulations have been performed and optimized by the most accurate softwares such as TOSCA, ANSYS, HFSS, SolidWorks and CST. Also, the manufacturing feasibility of all the parts is performed and their dimensions and parameters are synchronized with manufacturing standards
Maryland University sectored isochronous cyclotron (MUSIC): Progress report No. 32
Energy Technology Data Exchange (ETDEWEB)
1968-06-28
Completion of magnet tests, followed by completion of installation of major cyclotron components, are reported. Intermediate level power tests of the rf system are also reported. Design and fabrication of the control system are reported to be under way. (LEW)
Maryland University sectored isochronous cyclotron (MUSIC): Progress report No. 26
Energy Technology Data Exchange (ETDEWEB)
1968-01-17
Progress is reported in the fabrication, installation, and testing of cyclotron components, including magnets and coils, rf components, vacuum and control equipment. Also reported are magnet and rf component measurements. (LEW)
Maryland University sectored isochronous cyclotron (MUSIC): Progress report No. 23
Energy Technology Data Exchange (ETDEWEB)
1967-10-09
Progress is reported in the design, installation of various components of the cyclotron, including coils, magnets, rf system, and vacuum system. Also reported are measurements on magnets and rf components. (LEW)
Maryland University sectored isochronous cyclotron (MUSIC): Progress report No. 20
Energy Technology Data Exchange (ETDEWEB)
1967-06-30
Progress is reported in the fabrication and testing of cyclotron components, including magnet system and rf system components. Work on vacuum components and instrumentation and control equipment is also reported. (LEW)
Fusion Reactivity in the Case of Ion Cyclotron Resonant Heating
Institute of Scientific and Technical Information of China (English)
俞国扬; 常永斌; 沈林芳
2003-01-01
By applying the integral-variable-change technique,an explicit expression of deuterium-tritium fusion reactivity in the case of second harmonic ion cyclotron resonant heating on deuterium is obtained.
Effect of EMIC Wave Normal Angle Distribution on Relativistic Electron Scattering
Gamayunov, K. V.; Khazanov, G. V.
2006-01-01
The flux level of outer-zone relativistic electrons (above 1 MeV) is extremely variable during geomagnetic storms, and controlled by a competition between acceleration and loss. Precipitation of these electrons due to resonant pitch-angle scattering by electromagnetic ion cyclotron (EMIC) waves is considered one of the major loss mechanisms. This mechanism was suggested in early theoretical studies more than three decades ago. However, direct experimental evidence of the wave role in relativistic electrons precipitation is difficult to obtain because of lack of concurrent measurements of precipitating electrons at low altitudes and the waves in a magnetically conjugate equatorial region. Recently, the data from balloon-borne X-ray instruments provided indirect but strong evidence on an efficiency of the EMIC wave induced loss for the outer-zone relativistic electrons. These observations stimulated theoretical studies that, particularly, demonstrated that EMIC wave induced pitch-angle diffusion of MeV electrons can operate in the strong diffusion limit and this mechanism can compete with relativistic electron depletion caused by the Dst effect during the initial and main phases of storm. Although an effectiveness of relativistic electron scattering by EMIC waves depends strongly on the wave spectral properties, the most favorable assumptions regarding wave characteristics has been made in all previous theoretical studies. Particularly, only quasi field-aligned EMIC waves have been considered as a driver for relativistic electron loss. At the same time, there is growing experimental and theoretical evidence that these waves can be highly oblique; EMIC wave energy can occupy not only the region of generation, i.e. the region of small wave normal angles, but also the entire wave normal angle region, and even only the region near 90 degrees. The latter can dramatically change he effectiveness of relativistic electron scattering by EMIC waves. In the present study, we
Fast lattice Boltzmann solver for relativistic hydrodynamics.
Mendoza, M; Boghosian, B M; Herrmann, H J; Succi, S
2010-07-01
A lattice Boltzmann formulation for relativistic fluids is presented and numerically validated through quantitative comparison with recent hydrodynamic simulations of relativistic fluids. In order to illustrate its capability to handle complex geometries, the scheme is also applied to the case of a three-dimensional relativistic shock wave, generated by a supernova explosion, impacting on a massive interstellar cloud. This formulation opens up the possibility of exporting the proven advantages of lattice Boltzmann methods, namely, computational efficiency and easy handling of complex geometries, to the context of (mildly) relativistic fluid dynamics at large, from quark-gluon plasmas up to supernovae with relativistic outflows.
Ion-Beam-Excited Electrostatic Ion Cyclotron Waves
DEFF Research Database (Denmark)
Michelsen, Poul; Pécseli, Hans; Juul Rasmussen, Jens
1976-01-01
Self-excited electrostatic ion cyclotron waves were observed in an ion-beam-plasma system produced in a DP-operated Q-machine. The frequency of the waves showed the theoretically predicted variation with the magnetic field.......Self-excited electrostatic ion cyclotron waves were observed in an ion-beam-plasma system produced in a DP-operated Q-machine. The frequency of the waves showed the theoretically predicted variation with the magnetic field....
Kiyan, I N; Vorozhtsov, S B
2002-01-01
The Cyclotron Analytic Model Program (CAMP) written in C++ with the use of Visual C++ is described. The program is intended for the mean magnetic field calculation of the isochronous cyclotron with allowance for flutter. The program algorithm was developed on the basis of the paper 'Calculation of Isochronous Fields for Sector-Focused Cyclotrons', by M.M.Gordon (Particle Accelerators. 1983. V.13). The accuracy of the calculations, performed with this program, was tested with the use of maps of isochronous magnetic fields of different cyclotrons with the azimuthally varying fields - AVF cyclotrons, in which the ion beams were produced. The calculation by CAMP showed that the isochronous mean magnetic field curve for the measured magnetic field, in which the ion beam was produced, exactly corresponded to the curve of the isochronous mean magnetic field, calculated with the allowance for flutter for all the AVF cyclotrons that were considered. As is evident from the calculations, this program can be used for cal...
Energy Technology Data Exchange (ETDEWEB)
Artemyev, A. V., E-mail: ante0226@gmail.com [Space Research Institute, RAS, Moscow (Russian Federation); Mourenas, D.; Krasnoselskikh, V. V. [LPC2E/CNRS - University of Orleans, Orleans (France); Agapitov, O. V. [Space Sciences Laboratory, University of California, Berkeley, California 94720 (United States)
2015-06-15
In this paper, we study relativistic electron scattering by fast magnetosonic waves. We compare results of test particle simulations and the quasi-linear theory for different spectra of waves to investigate how a fine structure of the wave emission can influence electron resonant scattering. We show that for a realistically wide distribution of wave normal angles θ (i.e., when the dispersion δθ≥0.5{sup °}), relativistic electron scattering is similar for a wide wave spectrum and for a spectrum consisting in well-separated ion cyclotron harmonics. Comparisons of test particle simulations with quasi-linear theory show that for δθ>0.5{sup °}, the quasi-linear approximation describes resonant scattering correctly for a large enough plasma frequency. For a very narrow θ distribution (when δθ∼0.05{sup °}), however, the effect of a fine structure in the wave spectrum becomes important. In this case, quasi-linear theory clearly fails in describing accurately electron scattering by fast magnetosonic waves. We also study the effect of high wave amplitudes on relativistic electron scattering. For typical conditions in the earth's radiation belts, the quasi-linear approximation cannot accurately describe electron scattering for waves with averaged amplitudes >300 pT. We discuss various applications of the obtained results for modeling electron dynamics in the radiation belts and in the Earth's magnetotail.
Nonlinear ion-acoustic cnoidal waves in a dense relativistic degenerate magnetoplasma
El-Shamy, E. F.
2015-03-01
The complex pattern and propagation characteristics of nonlinear periodic ion-acoustic waves, namely, ion-acoustic cnoidal waves, in a dense relativistic degenerate magnetoplasma consisting of relativistic degenerate electrons and nondegenerate cold ions are investigated. By means of the reductive perturbation method and appropriate boundary conditions for nonlinear periodic waves, a nonlinear modified Korteweg-de Vries (KdV) equation is derived and its cnoidal wave is analyzed. The various solutions of nonlinear ion-acoustic cnoidal and solitary waves are presented numerically with the Sagdeev potential approach. The analytical solution and numerical simulation of nonlinear ion-acoustic cnoidal waves of the nonlinear modified KdV equation are studied. Clearly, it is found that the features (amplitude and width) of nonlinear ion-acoustic cnoidal waves are proportional to plasma number density, ion cyclotron frequency, and direction cosines. The numerical results are applied to high density astrophysical situations, such as in superdense white dwarfs. This research will be helpful in understanding the properties of compact astrophysical objects containing cold ions with relativistic degenerate electrons.
Electron cyclotron emission diagnostic for ITER.
Rowan, W; Austin, M; Beno, J; Ellis, R; Feder, R; Ouroua, A; Patel, A; Phillips, P
2010-10-01
Electron temperature measurements and electron thermal transport inferences will be critical to the nonactive and deuterium phases of ITER operation and will take on added importance during the alpha heating phase. The diagnostic must meet stringent criteria on spatial coverage and spatial resolution during full field operation. During the early phases of operation, it must operate equally well at half field. The key to the diagnostic is the front end design. It consists of a quasioptical antenna and a pair of calibration sources. The radial resolution of the diagnostic is less than 0.06 m. The spatial coverage extends at least from the core to the separatrix with first harmonic O-mode being used for the core and second harmonic X-mode being used for the pedestal. The instrumentation used for the core measurement at full field can be used for detection at half field by changing the detected polarization. Intermediate fields are accessible. The electron cyclotron emission systems require in situ calibration, which is provided by a novel hot calibration source. The critical component for the hot calibration source, the emissive surface, has been successfully tested. A prototype hot calibration source has been designed, making use of extensive thermal and mechanical modeling.
Cyclotron-based effects on plant gravitropism
Kordyum, E.; Sobol, M.; Kalinina, Ia.; Bogatina, N.; Kondrachuk, A.
Primary roots exhibit positive gravitropism and grow in the direction of the gravitational vector, while shoots respond negatively and grow opposite to the gravitational vector. We first demonstrated that the use of a weak combined magnetic field (CMF), which is comprised of a permanent magnetic field and an alternating magnetic field with the frequency resonance of the cyclotron frequency of calcium ions, can change root gravitropism from a positive direction to negative direction. Two-day-old cress seedlings were gravistimulated in a chamber that was placed into a μ-metal shield where this CMF was created. Using this "new model" of a root gravitropic response, we have studied some of its components including the movement of amyloplasts-statoliths in root cap statocytes and the distribution of Ca 2+ ions in the distal elongation zone during gravistimulation. Unlike results from the control, amyloplasts did not sediment in the distal part of a statocyte, and more Ca 2+ accumulation was observed in the upper side of a gravistimulated root for seedlings treated with the CMF. For plants treated with the CMF, it appears that a root gravitropic reaction occurs by a normal physiological process resulting in root bending although in the opposite direction. These results support the hypothesis that both the amyloplasts in the root cap statocytes and calcium are important signaling components in plant gravitropism.
Relativistic electron beams above thunderclouds
DEFF Research Database (Denmark)
Füellekrug, M.; Roussel-Dupre, R.; Symbalisty, E. M. D.;
2011-01-01
Non-luminous relativistic electron beams above thunderclouds have been detected by the radio signals of low frequency similar to 40-400 kHz which they radiate. The electron beams occur similar to 2-9 ms after positive cloud-to-ground lightning discharges at heights between similar to 22-72 km above...... thunderclouds. Intense positive lightning discharges can also cause sprites which occur either above or prior to the electron beam. One electron beam was detected without any luminous sprite which suggests that electron beams may also occur independently of sprites. Numerical simulations show that beams...... of electrons partially discharge the lightning electric field above thunderclouds and thereby gain a mean energy of similar to 7MeV to transport a total charge of similar to-10mC upwards. The impulsive current similar to 3 x 10(-3) Am-2 associated with relativistic electron beams above thunderclouds...
Relativistic electron beams above thunderclouds
Directory of Open Access Journals (Sweden)
M. Füllekrug
2011-05-01
Full Text Available Non-luminous relativistic electron beams above thunderclouds are detected by radio remote sensing with low frequency radio signals from 40–400 kHz. The electron beams occur 2–9 ms after positive cloud-to-ground lightning discharges at heights between 22–72 km above thunderclouds. The positive lightning discharges also cause sprites which occur either above or before the electron beam. One electron beam was detected without any luminous sprite occurrence which suggests that electron beams may also occur independently. Numerical simulations show that the beamed electrons partially discharge the lightning electric field above thunderclouds and thereby gain a mean energy of 7 MeV to transport a total charge of 10 mC upwards. The impulsive current associated with relativistic electron beams above thunderclouds is directed downwards and needs to be considered as a novel element of the global atmospheric electric circuit.
Volatility smile as relativistic effect
Kakushadze, Zura
2017-06-01
We give an explicit formula for the probability distribution based on a relativistic extension of Brownian motion. The distribution (1) is properly normalized and (2) obeys the tower law (semigroup property), so we can construct martingales and self-financing hedging strategies and price claims (options). This model is a 1-constant-parameter extension of the Black-Scholes-Merton model. The new parameter is the analog of the speed of light in Special Relativity. However, in the financial context there is no ;speed limit; and the new parameter has the meaning of a characteristic diffusion speed at which relativistic effects become important and lead to a much softer asymptotic behavior, i.e., fat tails, giving rise to volatility smiles. We argue that a nonlocal stochastic description of such (Lévy) processes is inadequate and discuss a local description from physics. The presentation is intended to be pedagogical.
Double Relativistic Electron Accelerating Mirror
Directory of Open Access Journals (Sweden)
Saltanat Sadykova
2013-02-01
Full Text Available In the present paper, the possibility of generation of thin dense relativistic electron layers is shown using the analytical and numerical modeling of laser pulse interaction with ultra-thin layers. It was shown that the maximum electron energy can be gained by optimal tuning between the target width, intensity and laser pulse duration. The optimal parameters were obtained from a self-consistent system of Maxwell equations and the equation of motion of electron layer. For thin relativistic electron layers, the gaining of maximum electron energies requires a second additional overdense plasma layer, thus cutting the laser radiation off the plasma screen at the instant of gaining the maximum energy (DREAM-schema.
Relativistic stars in bigravity theory
Aoki, Katsuki; Tanabe, Makoto
2016-01-01
Assuming static and spherically symmetric spacetimes in the ghost-free bigravity theory, we find a relativistic star solution, which is very close to that in general relativity. The coupling constants are classified into two classes: Class [I] and Class [II]. Although the Vainshtein screening mechanism is found in the weak gravitational field for both classes, we find that there is no regular solution beyond the critical value of the compactness in Class [I]. This implies that the maximum mass of a neutron star in Class [I] becomes much smaller than that in GR. On the other hand, for the solution in Class [II], the Vainshtein screening mechanism works well even in a relativistic star and the result in GR is recovered.
Relativistic Hydrodynamics on Graphic Cards
Gerhard, Jochen; Bleicher, Marcus
2012-01-01
We show how to accelerate relativistic hydrodynamics simulations using graphic cards (graphic processing units, GPUs). These improvements are of highest relevance e.g. to the field of high-energetic nucleus-nucleus collisions at RHIC and LHC where (ideal and dissipative) relativistic hydrodynamics is used to calculate the evolution of hot and dense QCD matter. The results reported here are based on the Sharp And Smooth Transport Algorithm (SHASTA), which is employed in many hydrodynamical models and hybrid simulation packages, e.g. the Ultrarelativistic Quantum Molecular Dynamics model (UrQMD). We have redesigned the SHASTA using the OpenCL computing framework to work on accelerators like graphic processing units (GPUs) as well as on multi-core processors. With the redesign of the algorithm the hydrodynamic calculations have been accelerated by a factor 160 allowing for event-by-event calculations and better statistics in hybrid calculations.
A relativistic symmetry in nuclei
Energy Technology Data Exchange (ETDEWEB)
Ginocchio, J N [MS B283, Theoretical Division, Los Alamos National Laboratory Los Alamos, New Mexico 87545 (Mexico)
2007-11-15
We review some of the empirical and theoretical evidence supporting pseudospin symmetry in nuclei as a relativistic symmetry. We review the case that the eigenfunctions of realistic relativistic nuclear mean fields approximately conserve pseudospin symmetry in nuclei. We discuss the implications of pseudospin symmetry for magnetic dipole transitions and Gamow-Teller transitions between states in pseudospin doublets. We explore a more fundamental rationale for pseudospin symmetry in terms of quantum chromodynamics (QCD), the basic theory of the strong interactions. We show that pseudospin symmetry in nuclei implies spin symmetry for an anti-nucleon in a nuclear environment. We also discuss the future and what role pseudospin symmetry may be expected to play in an effective field theory of nucleons.
Fluctuations in Relativistic Causal Hydrodynamics
Kumar, Avdhesh; Mishra, Ananta P
2013-01-01
The formalism to calculate the hydrodynamics fluctuation using the quasi-stationary fluctuation theory of Onsager to the relativistic Navier-Stokes hydrodynamics is already known. In this work we calculate hydrodynamic fluctuations in relativistic causal theory of Muller, Israel and Stewart and other related causal hydrodynamic theories. We show that expressions for the Onsager coefficients and the correlation functions have form similar to the ones obtained by using Navier-Stokes equation. However, temporal evolution of the correlation functions obtained using MIS and the other causal theories can be significantly different than the correlation functions obtained using the Navier-Stokes equation. Finally, as an illustrative example, we explicitly plot the correlation functions obtained using the causal-hydrodynamics theories and compare them with correlation functions obtained by earlier authors using the expanding boost-invariant (Bjorken) flows.
A small low energy cyclotron for radioisotope measurements
Energy Technology Data Exchange (ETDEWEB)
Bertsche, K.J.
1989-11-01
Direct detection of {sup 14}C by accelerator mass spectrometry has proved to be a much more sensitive method for radiocarbon dating than the decay counting method invented earlier by Libby. A small cyclotron (the cyclotrino'') was proposed for direct detection of radiocarbon in 1980. This combined the suppression of background through the use of negative ions, which had been used effectively in tandem accelerators, with the high intrinsic mass resolution of a cyclotron. Development of a small electrostatically-focused cyclotron for use as a mass spectrometer was previously reported but the sensitivity needed for detection of {sup 14}C at natural abundance was not achieved. The major contributions of this work are the integration of a high current external ion source with a small flat-field, electrostatically-focused cyclotron to comprise a system capable of measuring {sup 14}C at natural levels, and the analysis of ion motion in such a cyclotron, including a detailed analysis of phase bunching and its effect on mass resolution. A high current cesium sputter negative ion source generates a beam of carbon ions which is pre-separated with a Wien filter and is transported to the cyclotron via a series of electrostatic lenses. Beam is injected radially into the cyclotron using electrostatic deflectors and an electrostatic mirror. Axial focusing is entirely electrostatic. A microchannel plate detector is used with a phase-grated output. In its present form the system is capable of improving the sensitivity of detecting {sup 14}C in some biomedical experiments by a factor of 10{sup 4}. Modifications are discussed which could bring about an additional factor of 100 in sensitivity, which is important for archaeological and geological applications. Possibilities for measurements of other isotopes, such as {sup 3}H, and {sup 10}Be, and {sup 26}Al, are discussed. 70 refs.
Estimations of expectedness and potential surprise in possibility theory
Prade, Henri; Yager, Ronald R.
1992-01-01
This note investigates how various ideas of 'expectedness' can be captured in the framework of possibility theory. Particularly, we are interested in trying to introduce estimates of the kind of lack of surprise expressed by people when saying 'I would not be surprised that...' before an event takes place, or by saying 'I knew it' after its realization. In possibility theory, a possibility distribution is supposed to model the relative levels of mutually exclusive alternatives in a set, or equivalently, the alternatives are assumed to be rank-ordered according to their level of possibility to take place. Four basic set-functions associated with a possibility distribution, including standard possibility and necessity measures, are discussed from the point of view of what they estimate when applied to potential events. Extensions of these estimates based on the notions of Q-projection or OWA operators are proposed when only significant parts of the possibility distribution are retained in the evaluation. The case of partially-known possibility distributions is also considered. Some potential applications are outlined.
10 years of surprises at Saturn: CAPS and INMS highlights
Coates, A. J.; Waite, J. H.
2014-04-01
The Cassini mission at Saturn has provided many surprises on Saturn's rapidly rotating magnetosphere and its interaction with the diverse moons, as well as its interaction with the solar wind. One of the early discoveries was the water-rich composition of the magnetosphere. Its structure and dynamics indicate remarkable injections, periodicities and interchange events. Enceladus, orbiting at 4 RS, was found to have plumes of water vapour and ice which are the dominant source for the inner magnetosphere. Charged water clusters, charged dust and photoelectrons provide key populations in the 'dusty plasma' seen here, as well as chemical complexity in the plume material. Direct pickup is seen near Enceladus and field aligned currents create a spot in Saturn's aurora. At Titan, orbiting at 20 RS, heavy negative and positive ions are seen in the ionosphere, as well as neutrals, all of which have surprising chemical complexity. These provide the source for Titan's haze. Ionospheric plasma is seen in Titan's tail, enabling ion escape to be estimated at 7 tonnes per day. Saturn's ring ionosphere was seen early in the mission, which was oxygen rich and produced photoelectrons; a return will be made in 2017. At Rhea, pickup positive and negative ions indicated weak atmospheres sustained by energetic particle impact, seen in the neutrals also. A weak atmosphere was also seen at Dione. The exosphere production process operates at Jupiter's moons also. Here we review some of the key new results, and discuss the implications for other solar system contexts.
Thermodynamic and relativistic uncertainty relations
Artamonov, A. A.; Plotnikov, E. M.
2017-01-01
Thermodynamic uncertainty relation (UR) was verified experimentally. The experiments have shown the validity of the quantum analogue of the zeroth law of stochastic thermodynamics in the form of the saturated Schrödinger UR. We have also proposed a new type of UR for the relativistic mechanics. These relations allow us to consider macroscopic phenomena within the limits of the ratio of the uncertainty relations for different physical quantities.
Pythagoras Theorem and Relativistic Kinematics
Mulaj, Zenun; Dhoqina, Polikron
2010-01-01
In two inertial frames that move in a particular direction, may be registered a light signal that propagates in an angle with this direction. Applying Pythagoras theorem and principles of STR in both systems, we can derive all relativistic kinematics relations like the relativity of simultaneity of events, of the time interval, of the length of objects, of the velocity of the material point, Lorentz transformations, Doppler effect and stellar aberration.
Trembling motion of relativistic electrons in a magnetic field
Rusin, Tomasz M
2010-01-01
One-electron 3+1 and 2+1 Dirac equations are used to calculate the motion of a relativistic electron in a vacuum in the presence of an external magnetic field. First, calculations are carried on an operator level and exact analytical results are obtained for the electron trajectories which contain both intraband frequency components, identified as the cyclotron motion, as well as interband frequency components, identified as the trembling motion (Zitterbewegung, ZB). Next, time-dependent Heisenberg operators are used for the same problem to compute average values of electron position and velocity employing Gaussian wave packets. It is shown that the presence of a magnetic field and the resulting quantization of the energy spectrum has pronounced effects on the electron Zitterbewegung: it introduces intraband frequency components into the motion, influences all the frequencies and makes the motion stationary (not decaying in time) in case of the 2+1 Dirac equation. Finally, simulations of the 2+1 Dirac equatio...
Relativistic Binaries in Globular Clusters
Directory of Open Access Journals (Sweden)
Benacquista Matthew J.
2006-02-01
Full Text Available The galactic population of globular clusters are old, dense star systems, with a typical cluster containing 10^4 - 10^7 stars. As an old population of stars, globular clusters contain many collapsed and degenerate objects. As a dense population of stars, globular clusters are the scene of many interesting close dynamical interactions between stars. These dynamical interactions can alter the evolution of individual stars and can produce tight binary systems containing one or two compact objects. In this review, we discuss the theoretical models of globular cluster evolution and binary evolution, techniques for simulating this evolution which lead to relativistic binaries, and current and possible future observational evidence for this population. Globular cluster evolution will focus on the properties that boost the production of hard binary systems and on the tidal interactions of the galaxy with the cluster, which tend to alter the structure of the globular cluster with time. The interaction of the components of hard binary systems alters the evolution of both bodies and can lead to exotic objects. Direct N-body integrations and Fokker-Planck simulations of the evolution of globular clusters that incorporate tidal interactions and lead to predictions of relativistic binary populations are also discussed. We discuss the current observational evidence for cataclysmic variables, millisecond pulsars, and low-mass X-ray binaries as well as possible future detection of relativistic binaries with gravitational radiation.
Relativistic Binaries in Globular Clusters
Directory of Open Access Journals (Sweden)
Benacquista Matthew
2002-01-01
Full Text Available The galactic population of globular clusters are old, dense star systems, with a typical cluster containing $10^4 - 10^6$ stars. As an old population of stars, globular clusters contain many collapsed and degenerate objects. As a dense population of stars, globular clusters are the scene of many interesting close dynamical interactions between stars. These dynamical interactions can alter the evolution of individual stars and can produce tight binary systems containing one or two compact objects. In this review, we discuss the theoretical models of globular cluster evolution and binary evolution, techniques for simulating this evolution which lead to relativistic binaries, and current and possible future observational evidence for this population. Globular cluster evolution will focus on the properties that boost the production of hard binary systems and on the tidal interactions of the galaxy with the cluster, which tend to alter the structure of the globular cluster with time. The interaction of the components of hard binary systems alters the evolution of both bodies and can lead to exotic objects. Direct $N$-body integrations and Fokker--Planck simulations of the evolution of globular clusters that incorporate tidal interactions and lead to predictions of relativistic binary populations are also discussed. We discuss the current observational evidence for cataclysmic variables, millisecond pulsars, and low-mass X-ray binaries as well as possible future detection of relativistic binaries with gravitational radiation.
Relativistic Binaries in Globular Clusters
Directory of Open Access Journals (Sweden)
Matthew J. Benacquista
2013-03-01
Full Text Available Galactic globular clusters are old, dense star systems typically containing 10^4 – 10^6 stars. As an old population of stars, globular clusters contain many collapsed and degenerate objects. As a dense population of stars, globular clusters are the scene of many interesting close dynamical interactions between stars. These dynamical interactions can alter the evolution of individual stars and can produce tight binary systems containing one or two compact objects. In this review, we discuss theoretical models of globular cluster evolution and binary evolution, techniques for simulating this evolution that leads to relativistic binaries, and current and possible future observational evidence for this population. Our discussion of globular cluster evolution will focus on the processes that boost the production of tight binary systems and the subsequent interaction of these binaries that can alter the properties of both bodies and can lead to exotic objects. Direct N-body integrations and Fokker–Planck simulations of the evolution of globular clusters that incorporate tidal interactions and lead to predictions of relativistic binary populations are also discussed. We discuss the current observational evidence for cataclysmic variables, millisecond pulsars, and low-mass X-ray binaries as well as possible future detection of relativistic binaries with gravitational radiation.
Relativistic Tennis Using Flying Mirror
Pirozhkov, A. S.; Kando, M.; Esirkepov, T. Zh.; Ma, J.; Fukuda, Y.; Chen, L.-M.; Daito, I.; Ogura, K.; Homma, T.; Hayashi, Y.; Kotaki, H.; Sagisaka, A.; Mori, M.; Koga, J. K.; Kawachi, T.; Daido, H.; Bulanov, S. V.; Kimura, T.; Kato, Y.; Tajima, T.
2008-06-01
Upon reflection from a relativistic mirror, the electromagnetic pulse frequency is upshifted and the duration is shortened by the factor proportional to the relativistic gamma-factor squared due to the double Doppler effect. We present the results of the proof-of-principle experiment for frequency upshifting of the laser pulse reflected from the relativistic "flying mirror", which is a wake wave near the breaking threshold created by a strong driver pulse propagating in underdense plasma. Experimentally, the wake wave is created by a 2 TW, 76 fs Ti:S laser pulse from the JLITE-X laser system in helium plasma with the electron density of ≈4-6×1019 cm-3. The reflected signal is observed with a grazing-incidence spectrograph in 24 shots. The wavelength of the reflected radiation ranges from 7 to 14 nm, the corresponding frequency upshifting factors are ˜55-115, and the gamma-factors are y = 4-6. The reflected signal contains at least 3×107 photons/sr. This effect can be used to generate coherent high-frequency ultrashort pulses that inherit temporal shape and polarization from the original (low-frequency) ones. Apart from this, the reflected radiation contains important information about the wake wave itself, e.g. location, size, phase velocity, etc.
Magnetohydrodynamics of Chiral Relativistic Fluids
Boyarsky, Alexey; Ruchayskiy, Oleg
2015-01-01
We study the dynamics of a plasma of charged relativistic fermions at very high temperature $T\\gg m$, where $m$ is the fermion mass, coupled to the electromagnetic field. In particular, we derive a magneto-hydrodynamical description of the evolution of such a plasma. We show that, as compared to conventional MHD for a plasma of non-relativistic particles, the hydrodynamical description of the relativistic plasma involves new degrees of freedom described by a pseudo-scalar field originating in a local asymmetry in the densities of left-handed and right-handed fermions. This field can be interpreted as an effective axion field. Taking into account the chiral anomaly we present dynamical equations for the evolution of this field, as well as of other fields appearing in the MHD description of the plasma. Due to its non-linear coupling to helical magnetic fields, the axion field significantly affects the dynamics of a magnetized plasma and can give rise to a novel type of inverse cascade.
The Thomas-Fermi Quark Model: Non-Relativistic Aspects
Liu, Quan
2012-01-01
Non-relativistic aspects of the Thomas-Fermi statistical quark model are developed. A review is given and our modified approach to spin in the model is explained. Our results are limited so far to two inequivalent simultaneous wave functions which can apply to multiple degenerate flavors. An explicit spin interaction is introduced, which requires the introduction of a generalized spin "flavor". Although the model is designed to be most reliable for many-quark states, we find surprisingly that it may be used to fit the low energy spectrum of octet and decouplet baryons. The low energy fit allows us to investigate the six-quark doubly strange H-dibaryon state, possible 6 quark nucleon-nucleon resonances and flavor symmetric strange states of higher quark content.
Chemical freeze-out in relativistic heavy-ion collisions
Xu, Jun; Ko, Che Ming
2017-09-01
One surprising result in relativistic heavy-ion collisions is that the abundance of various particles measured in experiments is consistent with the picture that they reach chemical equilibrium at a temperature much higher than the temperature they freeze out kinetically. Using a multiphase transport model to study particle production in these collisions, we find, as an example, that the effective pion to nucleon ratio, which includes those from resonance decays, indeed changes very little during the evolution of the hadronic matter from the chemical to the kinetic freeze-out, and it is also accompanied by an almost constant specific entropy. We further use a hadron resonance gas model to illustrate the results from the transport model study.
Relativistic effects in Lyman-alpha forest
Iršič, Vid; Viel, Matteo
2015-01-01
We present the calculation of the Lyman-alpha (Lyman-$\\alpha$) transmitted flux fluctuations with full relativistic corrections to the first order. Even though several studies exist on relativistic effects in galaxy clustering, this is the first study to extend the formalism to a different tracer of underlying matter at unique redshift range ($z = 2 - 5$). Furthermore, we show a comprehensive application of our calculations to the Quasar- Lyman-$\\alpha$ cross-correlation function. Our results indicate that the signal of relativistic effects can be as large as 30% at Baryonic Acoustic Oscillation (BAO) scale, which is much larger than anticipated and mainly due to the large differences in density bias factors of our tracers. We construct an observable, the anti-symmetric part of the cross- correlation function, that is dominated by the relativistic signal and offers a new way to measure the relativistic terms at relatively small scales. The analysis shows that relativistic effects are important when considerin...
Transverse relativistic effects in paraxial wave interference
Bliokh, Konstantin Y; Nori, Franco
2013-01-01
We consider relativistic deformations of interfering paraxial waves moving in the transverse direction. Owing to superluminal transverse phase velocities, noticeable deformations of the interference patterns arise when the waves move with respect to each other with non-relativistic velocities. Similar distortions also appear on a mutual tilt of the interfering waves, which causes a phase delay analogous to the relativistic time delay. We illustrate these observations by the interference between a vortex wave beam and a plane wave, which exhibits a pronounced deformation of the radial fringes into a fork-like pattern (relativistic Hall effect). Furthermore, we describe an additional relativistic motion of the interference fringes (a counter-rotation in the vortex case), which become noticeable at the same non-relativistic velocities.
Entropy current for non-relativistic fluid
Banerjee, Nabamita; Jain, Akash; Roychowdhury, Dibakar
2014-01-01
We study transport properties of a parity-odd, non-relativistic charged fluid in presence of background electric and magnetic fields. To obtain stress tensor and charged current for the non-relativistic system we start with the most generic relativistic fluid, living in one higher dimension and reduce the constituent equations along the light-cone direction. We also reduce the equation satisfied by the entropy current of the relativistic theory and obtain a consistent entropy current for the non-relativistic system (we call it "canonical form" of the entropy current). Demanding that the non-relativistic fluid satisfies the second law of thermodynamics we impose constraints on various first order transport coefficients. For parity even fluid, this is straight forward; it tells us positive definiteness of different transport coefficients like viscosity, thermal conductivity, electric conductivity etc. However for parity-odd fluid, canonical form of the entropy current fails to confirm the second law of thermody...
Design of RF system for CYCIAE-230 superconducting cyclotron
Yin, Zhiguo; Ji, Bin; Fu, Xiaoliang; Cao, Xuelong; Zhao, Zhenlu; Zhang, Tinajue
2017-05-01
The CYCIAE230 is a low-current, compact superconducting cyclotron designed for proton therapy. The Radio Frequency system consists of four RF cavities and applies second harmonic to accelerate beams. The driving power for the cavity system is estimated to be approximately 150 kW. The LLRF controller is a self-made device developed and tested at low power using a small-scale cavity model. In this paper, the resonator systems of an S.C. cyclotron in history are reviewed. Contrary to those RF systems, the cavities of the CYCIAE230 cyclotron connect two opposite dees. Two high-power RF windows are included in the system. Each window carries approximately 75 kW RF power from the driver to the cavities. Thus, the RF system for the CY-CIAE230 cyclotron is operated in driven push-pull mode. The two-way amplifier-coupler-cavity systems are operated with approximately the same amount of RF power but 180° out of phase compared with each other. The design, as well as the technical advantage and limitations of this operating mode, of the CYCIAE230 cyclotron RF system is analyzed.
Cyclotron-based of plant gravisensing
Kordyum, E.; Kalinina, Ia.; Bogatina, N.; Kondrachuk, A.
Roots exhibit positive gravitropism they grow in the direction of a gravitational vector while shoots respond negatively and grow opposite to a gravitational vector We first demonstrated the inversion of roots gravitropism from positive to negative one under gravistimulation in the weak combined magnetic field WCMF consisted of permanent magnetic field PMF with the magnitude of order of 50 mu T and altering magnetic field AMF with the 6 mu T magnitude and a frequency of 32 Hz It was found that the effect of inversion has a resonance nature It means that in the interval of frequencies 1-45 Hz inversion of root gravitropism occurs only at frequency 32 Hz 2-3-day old cress seedlings were gravistimulated in moist chambers which are placed in mu -metal shields Inside mu -metal shields combined magnetic fields have been created The magnitude of magnetic fields was measured by a flux-gate magnetometer Experiments were performed in darkness at temperature 20 pm 1 0 C We measured the divergence angle of a growing root from its horizontal position After 1 h of gravistimulation in the WCMF we observed negative gravitropism of cress roots i e they grow in the opposite direction to a gravitational vector Frequency of 32 Hz for the magnitude of the PMF applied formally corresponds to cyclotron frequency of Ca 2 ions This indicates possible participation of calcium ions in root gravitropism There are many evidences of resonance effects of the WCMF on the biological processes that involve Ca 2 but the nature of
Electron cyclotron emission radiometer upgrade on the J-TEXT tokamak
Yang, Z. J.; Pan, X. M.; Ma, X. D.; Ruan, B. W.; Zhou, R. B.; Zhang, C.
2016-11-01
To meet experimental requirements, the J-TEXT electron cyclotron emission (ECE) diagnostic is being upgraded. The front end antenna and transmission line have been modified and a new 8-channel W-band detecting unit has been developed. The improved ECE system will extend the frequency range from 94.5-124.5 GHz to 80.5-124.5 GHz. This will enable the system to cover the most plasma in the radius direction for BT = 1.8-2.2 T, and it even can cover almost the whole plasma range ρ = - 0.8-0.9 (minus means the high field side) at BT = 1.8 T. A new auxiliary channel bank with 8 narrow band, tunable yttrium iron garnet filters is planned to add to the ECE system. Due to observations along a major radius, perpendicular to BT, and relatively low electron temperature, Doppler and relativistic broadening are minimal and thus high spatial resolution measurements can be made at variable locations with these tunable channels.
Generation of auroral kilometric and Z mode radiation by the cyclotron maser mechanism
Omidi, N.; Gurnett, D. A.; Wu, C. S.
1984-01-01
The relativistic Doppler-shifted cyclotron resonance condition for EM wave interactions with a plasma defines an ellipse in velocity space when the product of the index of refraction and cosine of the wave normal angle is less than or equal to unity, and defines a partial ellipse when the product is greater than unity. It is also noted that waves with frequencies greater than the gyrofrequency can only resonate with particles moving in the same direction along the magnetic field, while waves with lower frequencies than these resonate with particles moving in both directions along the magnetic field. It is found, in the case of auroral kilometric radiation, that both the upgoing and the downgoing electrons are unstable and can give rise to this radiation's growth. The magnitudes of the growth rates for both the upgoing and downgoing auroral kilometric radiation are comparable, and indicate that the path lengths needed to account for the observed intensities of this radiation are of the order of a few hundred km, which is probably too large. Growth rate calculations for the Z mode radiation show that, for wave frequencies just below the gyrofrequency and wave normal angles at or near 90 deg, the electron distribution is unstable and the growth rates are large enough to account for the observed intensities.
Non-Relativistic Spacetimes with Cosmological Constant
Aldrovandi, R.; Barbosa, A. L.; Crispino, L.C.B.; Pereira, J. G.
1998-01-01
Recent data on supernovae favor high values of the cosmological constant. Spacetimes with a cosmological constant have non-relativistic kinematics quite different from Galilean kinematics. De Sitter spacetimes, vacuum solutions of Einstein's equations with a cosmological constant, reduce in the non-relativistic limit to Newton-Hooke spacetimes, which are non-metric homogeneous spacetimes with non-vanishing curvature. The whole non-relativistic kinematics would then be modified, with possible ...
Relativistic non-equilibrium thermodynamics revisited
García-Colin, L S
2006-01-01
Relativistic irreversible thermodynamics is reformulated following the conventional approach proposed by Meixner in the non-relativistic case. Clear separation between mechanical and non-mechanical energy fluxes is made. The resulting equations for the entropy production and the local internal energy have the same structure as the non-relativistic ones. Assuming linear constitutive laws, it is shown that consistency is obtained both with the laws of thermodynamics and causality.
Analogy betwen dislocation creep and relativistic cosmology
J.A. Montemayor-Aldrete; J.D. Muñoz-Andrade; Mendoza-Allende, A.; Montemayor-Varela, A.
2005-01-01
A formal, physical analogy between plastic deformation, mainly dislocation creep, and Relativistic Cosmology is presented. The physical analogy between eight expressions for dislocation creep and Relativistic Cosmology have been obtained. By comparing the mathematical expressions and by using a physical analysis, two new equations have been obtained for dislocation creep. Also, four new expressions have been obtained for Relativistic Cosmology. From these four new equations, one may determine...
A relativistic correction to semiclassical charmonium
Weiss, J.
1995-09-01
It is shown that the relativistic linear potentials, introduced by the author within the particle à la Wheeler-Feynman direct-interaction (AAD) theory, applied to the semiclassically quantized charmonium, yield energy spectrum comparable to that of some known models. Using the expansion of the relativistic linear AAD potentials in powers ofc -1, the charmonium spectrum, given as a rule by Bohr-Sommerfeld quantization of circular orbits, is extended up to the second order of relativistic corrections.
Generalized One-Dimensional Point Interaction in Relativistic and Non-relativistic Quantum Mechanics
Shigehara, T; Mishima, T; Cheon, T; Cheon, Taksu
1999-01-01
We first give the solution for the local approximation of a four parameter family of generalized one-dimensional point interactions within the framework of non-relativistic model with three neighboring $\\delta$ functions. We also discuss the problem within relativistic (Dirac) framework and give the solution for a three parameter family. It gives a physical interpretation for so-called high energy substantially differ between non-relativistic and relativistic cases.
Quark Gluon Plasma: Surprises from strongly coupled QCD matter
Jacak, Barbara
2017-01-01
Quantum Chromodynamics has long predicted a transition from normal hadronic matter to a phase where the quarks and gluons are no longer bound together and can move freely. Quark gluon plasma is now produced regularly in collisions of heavy nuclei at very high energy at both the Relativistic Heavy Ion Collider (RHIC) in the U.S. and at the LHC in Europe. Quark gluon plasma exhibits remarkable properties. Its vanishingly small shear viscosity to entropy density ratio means that it flows essentially without internal friction, making it one of the most ``perfect'' liquids known. It is also very opaque to transiting particles including heavy charm quarks, though the exact mechanism for this is not yet understood. Recent data suggest that even very small colliding systems may produce a droplet of plasma. The similarities to strongly coupled or correlated systems in ultra-cold atoms and condensed matter are striking, and have inspired novel theoretical descriptions growing out of string theory. It remains a mystery how this plasma emerges from cold, dense gluonic matter deep inside nuclei. I will discuss how a future electron-ion collider can help address this question.
Measured Zero Net Energy Performance: Results, Lessons, and Surprises
Energy Technology Data Exchange (ETDEWEB)
Brown, Carrie; LaRue, Anna; Pigman, Margaret; Roberts, Jon; Kaneda, David; Connelly, Dylan; Elliott, John; Pless, Shanti; Pande, Abhijeet; Dean, Edward; Anbarlilar, Can
2016-08-26
As more and more zero net energy (ZNE) buildings are built and monitored, we can learn from both careful case studies of individual projects as well as a broader perspective of trends over time. In a forum sponsored by Pacific Gas and Electric Company (PG&E), eight expert speakers discussed: results and lessons from monitoring occupied ZNE buildings; best practices for setting performance targets and getting actionable performance information, and; things that have surprised them about monitored ZNE buildings. This paper distills the content of the forum by laying out the most common hurdles that are encountered in setting up monitoring projects, frequent performance issues that the monitoring uncovers, and lessons learned that can be applied to future projects.
Surprising hair analysis results following acute carbofuran intoxication.
Dulaurent, S; Gaulier, J M; Zouaoui, K; Moesch, C; François, B; Lachâtre, G
2011-10-10
We present two non fatal cases of intoxication with carbofuran (CBF) documented by hair analysis. Carbofuran and 3-hydroxycarbofuran (OHCBF, its main metabolite) hair concentrations were determined using a liquid chromatography-tandem mass spectrometry method. The obtained results were surprising if we consider several hair analyses previously published and based on a theory of the presence of xenobiotic in the only segment that comprised its intake. Among the two intoxication cases, we noticed the presence of CBF and OHCBF in hair segments corresponding to 45 days before, and more than 100 days after, the day of intoxication. Additionally, repeated hair samplings and subsequent analysis revealed a decrease of the carbofuran's concentration during the hair life.
Physics Nobel prize 2004: Surprising theory wins physics Nobel
2004-01-01
From left to right: David Politzer, David Gross and Frank Wilczek. For their understanding of counter-intuitive aspects of the strong force, which governs quarks inside protons and neutrons, on 5 October three American physicists were awarded the 2004 Nobel Prize in Physics. David J. Gross (Kavli Institute of Theoretical Physics, University of California, Santa Barbara), H. David Politzer (California Institute of Technology), and Frank Wilczek (Massachusetts Institute of Technology) made a key theoretical discovery with a surprising result: the closer quarks are together, the weaker the force - opposite to what is seen with electromagnetism and gravity. Rather, the strong force is analogous to a rubber band stretching, where the force increases as the quarks get farther apart. These physicists discovered this property of quarks, known as asymptotic freedom, in 1976. It later became a key part of the theory of quantum chromodynamics (QCD) and the Standard Model, the current best theory to describe the interac...
Probability and Surprisal in Auditory Comprehension of Morphologically Complex Words
DEFF Research Database (Denmark)
Balling, Laura Winther; Baayen, R. Harald
2012-01-01
Two auditory lexical decision experiments document for morphologically complex words two points at which the probability of a target word given the evidence shifts dramatically. The first point is reached when morphologically unrelated competitors are no longer compatible with the evidence....... Adapting terminology from Marslen-Wilson (1984), we refer to this as the word’s initial uniqueness point (UP1). The second point is the complex uniqueness point (CUP) introduced by Balling and Baayen (2008), at which morphologically related competitors become incompatible with the input. Later initial...... in the course of the word co-determines response latencies. The presence of effects of surprisal, both at the initial uniqueness point of complex words, and cumulatively throughout the word, challenges the Shortlist B model of Norris and McQueen (2008), and suggests that a Bayesian approach to auditory...
2014 Presidential elections in Romania – surprising result or strategy
Directory of Open Access Journals (Sweden)
Dan Mihalache
2015-03-01
Full Text Available The presidential elections in Romania which took place in November 2014 were won by Klaus Iohannis, who clearly defeated the incumbent prime-minister Victor Ponta by 10%. The result was considered by many a surprise, as none of the opinion polls were able to predict it. This article reveals a part of the strategy of Klaus Iohannis’s campaign and it offers a few clues about how this is result was possible, without having the aim to explain it fully. As the authors were accountable for strategy and political message in the electoral campaign for Klaus Iohannis, the scientific approach is combined with the inside view, to provide the reader a better understanding of the November 2014 events.
Do non-relativistic neutrinos oscillate?
Akhmedov, Evgeny
2017-07-01
We study the question of whether oscillations between non-relativistic neutrinos or between relativistic and non-relativistic neutrinos are possible. The issues of neutrino production and propagation coherence and their impact on the above question are discussed in detail. It is demonstrated that no neutrino oscillations can occur when neutrinos that are non-relativistic in the laboratory frame are involved, except in a strongly mass-degenerate case. We also discuss how this analysis depends on the choice of the Lorentz frame. Our results are for the most part in agreement with Hinchliffe's rule.
Geometric Models of the Relativistic Harmonic Oscillator
Cotaescu, I I
1997-01-01
A family of relativistic geometric models is defined as a generalization of the actual anti-de Sitter (1+1) model of the relativistic harmonic oscillator. It is shown that all these models lead to the usual harmonic oscillator in the non-relativistic limit, even though their relativistic behavior is quite different. Among quantum models we find a set of models with countable energy spectra, and another one having only a finite number of energy levels and in addition a continuous spectrum.
Relativistic and non-relativistic solitons in plasmas
Barman, Satyendra Nath
This thesis entitled as "Relativistic and Non-relativistic Solitons in Plasmas" is the embodiment of a number of investigations related to the formation of ion-acoustic solitary waves in plasmas under various physical situations. The whole work of the thesis is devoted to the studies of solitary waves in cold and warm collisionless magnetized or unmagnetized plasmas with or without relativistic effect. To analyze the formation of solitary waves in all our models of plasmas, we have employed two established methods namely - reductive perturbation method to deduce the Korteweg-de Vries (KdV) equation, the solutions of which represent the important but near exact characteristic concepts of soliton-physics. Next, the pseudopotential method to deduce the energy integral with total nonlinearity in the coupling process for exact characteristic results of solitons has been incorporated. In Chapter 1, a brief description of plasma in nature and laboratory and its generation are outlined elegantly. The nonlinear differential equations to characterize solitary waves and the relevant but important methods of solutions have been mentioned in this chapter. The formation of solitary waves in unmagnetized and magnetized plasmas, and in relativistic plasmas has been described through mathematical entity. Applications of plasmas in different fields are also put forwarded briefly showing its importance. The study of plasmas as they naturally occur in the universe encompasses number of topics including sun's corona, solar wind, planetary magnetospheres, ionospheres, auroras, cosmic rays and radiation. The study of space weather to understand the universe, communications and the activities of weather satellites are some useful areas of space plasma physics. The surface cleaning, sterilization of food and medical appliances, killing of bacteria on various surfaces, destroying of viruses, fungi, spores and plasma coating in industrial instruments ( like computers) are some of the fields
Electric and Magnetic Vertical Focusing Study for 100 MeV High Intensity Proton Cyclotron
Institute of Scientific and Technical Information of China (English)
2008-01-01
<正>For the central region design of cyclotrons, the basic problem in the vertical motion is very different from the one in the radial motion. The reason is that vertical tune is almost zero at the center of cyclotrons,
Energy Technology Data Exchange (ETDEWEB)
Glantz, M.H.; Moore, C.M. [National Center for Atmospheric Research, Boulder, CO (United States); Streets, D.G.; Bhatti, N.; Rosa, C.H. [Argonne National Lab., IL (United States). Decision and Information Sciences Div.; Stewart, T.R. [State Univ. of New York, Albany, NY (United States)
1998-01-01
This report examines the concept of climate surprise and its implications for environmental policymaking. Although most integrated assessment models of climate change deal with average values of change, it is usually the extreme events or surprises that cause the most damage to human health and property. Current models do not help the policymaker decide how to deal with climate surprises. This report examines the literature of surprise in many aspects of human society: psychology, military, health care, humor, agriculture, etc. It draws together various ways to consider the concept of surprise and examines different taxonomies of surprise that have been proposed. In many ways, surprise is revealed to be a subjective concept, triggered by such factors as prior experience, belief system, and level of education. How policymakers have reacted to specific instances of climate change or climate surprise in the past is considered, particularly with regard to the choices they made between proactive and reactive measures. Finally, the report discusses techniques used in the current generation of assessment models and makes suggestions as to how climate surprises might be included in future models. The report concludes that some kinds of surprises are simply unpredictable, but there are several types that could in some way be anticipated and assessed, and their negative effects forestalled.
Vertical Electron Cyclotron Emission Diagnostic for TCV Plasmas
Directory of Open Access Journals (Sweden)
Goodman T. P.
2012-09-01
Full Text Available Electron cyclotron resonance heating (ECRH and electron cyclotron current drive (ECCD are used to heat the plasma, to tailor the current profiles and to achieve different operating regimes of tokamak plasmas. Plasmas with ECRH/ECCD are characterized by non-thermal electrons, which cannot be described by a Maxwellian distribution. Non-thermal electrons are also generated during MHD activity, like sawteeth crashes. Quantifying the non-thermal electron distribution is therefore a key for understanding EC heated fusion plasmas. For this purpose a vertical electron cyclotron emission (V-ECE diagnostic is being installed at TCV. The diagnostic layout, the calibration, the analysis technique for data interpretation, the physics potentials and limitations are discussed.
Calibration of the simulation model of the VINCY cyclotron magnet
Directory of Open Access Journals (Sweden)
Ćirković Saša
2002-01-01
Full Text Available The MERMAID program will be used to isochronise the nominal magnetic field of the VINCY Cyclotron. This program simulates the response, i. e. calculates the magnetic field, of a previously defined model of a magnet. The accuracy of 3D field calculation depends on the density of the grid points in the simulation model grid. The size of the VINCY Cyclotron and the maximum number of grid points in the XY plane limited by MERMAID define the maximumobtainable accuracy of field calculations. Comparisons of the field simulated with maximum obtainable accuracy with the magnetic field measured in the first phase of the VINCY Cyclotron magnetic field measurements campaign has shown that the difference between these two fields is not as small as required. Further decrease of the difference between these fields is obtained by the simulation model calibration, i. e. by adjusting the current through the main coils in the simulation model.
Cassini observations of ion cyclotron waves and ions anisotropy
Crary, F. J.; Dols, V. J.; Cassidy, T. A.; Tokar, R. L.
2013-12-01
In Saturn's equatorial, inner magnetosphere, the production of fresh ions in a pick-up distribution generates ion cyclotron waves. These waves are a sensitive indicator of fresh plasma production, but the quantitative relation between wave properties and ionization rates is nontrivial. We present a combined analysis of Cassini MAG and CAPS data, from a variety of equatorial orbits between 2005 and 2012. Using the MAG data, we determine the amplitude and peak frequency of ion cyclotron waves. From the CAPS data we extract the parallel and perpendicular velocity distribution of water group ions. We compare these results with hybrid simulations of the ion cyclotron instability and relate the observed wave amplitudes and ion velocity distributions to the production rate of pickup ions. The resulting relation between wave and plasma properties will allow us to infer ion production rates even at times when no direct ion measurements are available.
Design study of the KIRAMS-430 superconducting cyclotron magnet
Kim, Hyun Wook; Kang, Joonsun; Hong, Bong Hwan; Jung, In Su
2016-07-01
Design study of superconducting cyclotron magnet for the carbon therapy was performed at the Korea Institute of Radiological and Medical Science (KIRAMS). The name of this project is The Korea Heavy Ion Medical Accelerator (KHIMA) project and a fixed frequency cyclotron with four spiral sector magnet was one of the candidate for the accelerator type. Basic parameters of the cyclotron magnet and its characteristics were studied. The isochronous magnetic field which can guide the 12C6+ ions up to 430 MeV/u was designed and used for the single particle tracking simulation. The isochronous condition of magnetic field was achieved by optimization of sector gap and width along the radius. Operating range of superconducting coil current was calculated and changing of the magnetic field caused by mechanical deformations of yokes was considered. From the result of magnetic field design, structure of the magnet yoke was planned.
Accelerators for hadrontherapy: From Lawrence cyclotrons to linacs
Energy Technology Data Exchange (ETDEWEB)
Amaldi, U.; Bonomi, R.; Braccini, S., E-mail: Saverio.Braccini@cern.ch; Crescenti, M.; Degiovanni, A.; Garlasche, M.; Garonna, A.; Magrin, G.; Mellace, C.; Pearce, P.; Pitta, G.; Puggioni, P.; Rosso, E.; Verdu Andres, S.; Wegner, R.; Weiss, M.; Zennaro, R.
2010-08-21
Hadrontherapy with protons and carbon ions is a fast developing methodology in radiation oncology. The accelerators used and planned for this purpose are reviewed starting from the cyclotrons used in the thirties. As discussed in the first part of this paper, normal and superconducting cyclotrons are still employed, together with synchrotrons, for proton therapy while for carbon ion therapy synchrotrons have been till now the only option. The latest developments concern a superconducting cyclotron for carbon ion therapy, fast-cycling high frequency linacs and 'single room' proton therapy facilities. These issues are discussed in the second part of the paper by underlining the present challenges, in particular the treatment of moving organs.
Accelerators for hadrontherapy: From Lawrence cyclotrons to linacs
Braccini, S; Garlasche, M; Weiss, M; Crescenti, M; Pearce, P; Rosso, E; Wegner, R; Magrin, G; Pitta, G; Amaldi, U; Puggioni, P; Degiovanni, A; Mellace, C; Zennaro, R; Bonomi, R; Garonna, A
2010-01-01
Hadrontherapy with protons and carbon ions is a fast developing methodology in radiation oncology. The accelerators used and planned for this purpose are reviewed starting from the cyclotrons used in the thirties. As discussed in the first part of this paper, normal and superconducting cyclotrons are still employed, together with synchrotrons, for proton therapy while for carbon ion therapy synchrotrons have been till now the only option. The latest developments concern a superconducting cyclotron for carbon ion therapy, fast-cycling high frequency linacs and `single room' proton therapy facilities. These issues are discussed in the second part of the paper by underlining the present challenges, in particular the treatment of moving organs. (C) 2010 Elsevier B.V. All rights reserved.
Calibration of the simulation model of the Vincy cyclotron magnet
Cirkovic, S; Vorozhtsov, A S; Vorozhtsov, S B
2002-01-01
The MERMAID program will be used to isochronise the nominal magnetic field of the VINCY Cyclotron. This program simulates the response, i. e. calculates the magnetic field, of a previously defined model of a magnet. The accuracy of 3D field calculation depends on the density of the grid points in the simulation model grid. The size of the VINCY Cyclotron and the maximum number of grid points in the XY plane limited by MERMAID define the maximum obtainable accuracy of field calculations. Comparisons of the field simulated with maximum obtainable accuracy with the magnetic field measured in the first phase of the VINCY Cyclotron magnetic field measurements campaign has shown that the difference between these two fields is not as small as required. Further decrease of the difference between these fields is obtained by the simulation model calibration, i. e. by adjusting the current through the main coils in the simulation model.
Relativistic Corrections to the Bohr Model of the Atom
Kraft, David W.
1974-01-01
Presents a simple means for extending the Bohr model to include relativistic corrections using a derivation similar to that for the non-relativistic case, except that the relativistic expressions for mass and kinetic energy are employed. (Author/GS)
2D electron cyclotron emission imaging at ASDEX Upgrade (invited)
Energy Technology Data Exchange (ETDEWEB)
Classen, I. G. J. [Max Planck Institut fuer Plasmaphysik, 85748 Garching (Germany); FOM-Institute for Plasma Physics, Rijnhuizen, 3430 BE Nieuwegein (Netherlands); Boom, J. E.; Vries, P. C. de [FOM-Institute for Plasma Physics, Rijnhuizen, 3430 BE Nieuwegein (Netherlands); Suttrop, W.; Schmid, E.; Garcia-Munoz, M.; Schneider, P. A. [Max Planck Institut fuer Plasmaphysik, 85748 Garching (Germany); Tobias, B.; Domier, C. W.; Luhmann, N. C. Jr. [University of California at Davis, Davis, California 95616 (United States); Donne, A. J. H. [FOM-Institute for Plasma Physics, Rijnhuizen, 3430 BE Nieuwegein (Netherlands); Eindhoven University of Technology, 5600 MB Eindhoven (Netherlands); Jaspers, R. J. E. [Eindhoven University of Technology, 5600 MB Eindhoven (Netherlands); Park, H. K. [POSTECH, Pohang, Gyeongbuk, 790-784 (Korea, Republic of); Munsat, T. [University of Colorado, Boulder, Colorado 80309 (United States)
2010-10-15
The newly installed electron cyclotron emission imaging diagnostic on ASDEX Upgrade provides measurements of the 2D electron temperature dynamics with high spatial and temporal resolution. An overview of the technical and experimental properties of the system is presented. These properties are illustrated by the measurements of the edge localized mode and the reversed shear Alfven eigenmode, showing both the advantage of having a two-dimensional (2D) measurement, as well as some of the limitations of electron cyclotron emission measurements. Furthermore, the application of singular value decomposition as a powerful tool for analyzing and filtering 2D data is presented.
Electron cyclotron emission diagnostics on the large helical device
Nagayama, Y.; Kawahata, K.; England, A.; Ito, Y.; Bretz, N.; McCarthy, M.; Taylor, G.; Doane, J.; Ikezi, H.; Edlington, T.; Tomas, J.
1999-01-01
The electron cyclotron emission (ECE) diagnostic system is installed on the large helical device (LHD). The system includes the following instruments: a heterodyne radiometer, a Michelson spectrometer, and a grating polychromator. A 63.5 mm corrugated waveguide system is fully utilized. Large collection optics and notch filters at the frequency of the LHD electron cyclotron heating (ECH) were developed for this system. In addition to these filters, the rectangular waveguide notch filters, the ECE measurement with the radiometer has been successfully performed during the ECH.
Fluid equations in the presence of electron cyclotron current drive
Energy Technology Data Exchange (ETDEWEB)
Jenkins, Thomas G.; Kruger, Scott E. [Tech-X Corporation, 5621 Arapahoe Avenue, Boulder, Colorado 80303 (United States)
2012-12-15
Two-fluid equations, which include the physics imparted by an externally applied radiofrequency source near electron cyclotron resonance, are derived in their extended magnetohydrodynamic forms using the formalism of Hegna and Callen [Phys. Plasmas 16, 112501 (2009)]. The equations are compatible with the closed fluid/drift-kinetic model developed by Ramos [Phys. Plasmas 17, 082502 (2010); 18, 102506 (2011)] for fusion-relevant regimes with low collisionality and slow dynamics, and they facilitate the development of advanced computational models for electron cyclotron current drive-induced suppression of neoclassical tearing modes.
Electron Plasmas Cooled by Cyclotron-Cavity Resonance
Povilus, A P; Evans, L T; Evetts, N; Fajans, J; Hardy, W N; Hunter, E D; Martens, I; Robicheaux, F; Shanman, S; So, C; Wang, X; Wurtele, J S
2016-01-01
We observe that high-Q electromagnetic cavity resonances increase the cyclotron cooling rate of pure electron plasmas held in a Penning-Malmberg trap when the electron cyclotron frequency, controlled by tuning the magnetic field, matches the frequency of standing wave modes in the cavity. For certain modes and trapping configurations, this can increase the cooling rate by factors of ten or more. In this paper, we investigate the variation of the cooling rate and equilibrium plasma temperatures over a wide range of parameters, including the plasma density, plasma position, electron number, and magnetic field.
Magnetogenesis through Relativistic Velocity Shear
Miller, Evan
Magnetic fields at all scales are prevalent in our universe. However, current cosmological models predict that initially the universe was bereft of large-scale fields. Standard magnetohydrodynamics (MHD) does not permit magnetogenesis; in the MHD Faraday's law, the change in magnetic field B depends on B itself. Thus if B is initially zero, it will remain zero for all time. A more accurate physical model is needed to explain the origins of the galactic-scale magnetic fields observed today. In this thesis, I explore two velocity-driven mechanisms for magnetogenesis in 2-fluid plasma. The first is a novel kinematic 'battery' arising from convection of vorticity. A coupling between thermal and plasma oscillations, this non-relativistic mechanism can operate in flows that are incompressible, quasi-neutral and barotropic. The second mechanism results from inclusion of thermal effects in relativistic shear flow instabilities. In such flows, parallel perturbations are ubiquitously unstable at small scales, with growth rates of order with the plasma frequency over a defined range of parameter-space. Of these two processes, instabilities seem far more likely to account for galactic magnetic fields. Stable kinematic effects will, at best, be comparable to an ideal Biermann battery, which is suspected to be orders of magnitude too weak to produce the observed galactic fields. On the other hand, instabilities grow until saturation is reached, a topic that has yet to be explored in detail on cosmological scales. In addition to investigating these magnetogenesis sources, I derive a general dispersion relation for three dimensional, warm, two species plasma with discontinuous shear flow. The mathematics of relativistic plasma, sheared-flow instability and the Biermann battery are also discussed.
Relativistic Plasma Polarizer: Impact of Temperature Anisotropy on Relativistic Transparency
Hazeltine, R. D.; Stark, David J.; Bhattacharjee, Chinmoy; Arefiev, Alexey V.; Toncian, Toma; Mahajan, S. M.
2015-11-01
3D particle-in-cell simulations demonstrate that the enhanced transparency of a relativistically hot plasma is sensitive to how the energy is partitioned between different degrees of freedom. We consider here the simplest problem: the propagation of a low amplitude pulse through a preformed relativistically hot anisotropic electron plasma to explore its intrinsic dielectric properties. We find that: 1) the critical density for propagation depends strongly on the pulse polarization, 2) two plasmas with the same density and average energy per electron can exhibit profoundly different responses to electromagnetic pulses, 3) the anisotropy-driven Weibel instability develops as expected; the timescales of the growth and back reaction (on anisotropy), however, are long enough that sufficient anisotropy persists for the entire duration of the simulation. This plasma can then function as a polarizer or a wave plate to dramatically alter the pulse polarization. This work was supported by the U.S. DOE Contract Nos. DE-FG02-04ER54742 and DE-AC05-06OR23100 (D. J. S.) and NNSA Contract No. DE-FC52-08NA28512.
On the relativistic anisotropic configurations
Energy Technology Data Exchange (ETDEWEB)
Shojai, F. [University of Tehran, Department of Physics, Tehran (Iran, Islamic Republic of); Institute for Research in Fundamental Sciences (IPM), Foundations of Physics Group, School of Physics, Tehran (Iran, Islamic Republic of); Kohandel, M. [Alzahra University, Department of Physics and Chemistry, Tehran (Iran, Islamic Republic of); Stepanian, A. [University of Tehran, Department of Physics, Tehran (Iran, Islamic Republic of)
2016-06-15
In this paper we study anisotropic spherical polytropes within the framework of general relativity. Using the anisotropic Tolman-Oppenheimer-Volkov equations, we explore the relativistic anisotropic Lane-Emden equations. We find how the anisotropic pressure affects the boundary conditions of these equations. Also we argue that the behavior of physical quantities near the center of star changes in the presence of anisotropy. For constant density, a class of exact solution is derived with the aid of a new ansatz and its physical properties are discussed. (orig.)
Simple waves in relativistic fluids.
Lyutikov, Maxim
2010-11-01
We consider the Riemann problem for relativistic flows of polytropic fluids and find relations for the flow characteristics. Evolution of physical quantities takes especially simple form for the case of cold magnetized plasmas. We find exact explicit analytical solutions for one-dimensional expansion of magnetized plasma into vacuum, valid for arbitrary magnetization. We also consider expansion into cold unmagnetized external medium both for stationary initial conditions and for initially moving plasma, as well as reflection of rarefaction wave from a wall. We also find self-similar structure of three-dimensional magnetized outflows into vacuum, valid close to the plasma-vacuum interface.
Observation of relativistic antihydrogen atoms
Blanford, Glenn Delfosse, Jr.
1997-09-01
An observation of relativistic antihydrogen atoms is reported in this dissertation. Experiment 862 at Fermi National Accelerator Laboratory observed antihydrogen atoms produced by the interaction of a circulating beam of high momentum (3 production is outlined within. The cross section corresponds to the process where a high momentum antiproton causes e+e/sp- pair creation near a nucleus with the e+ being captured by the antiproton. Antihydrogen is the first atom made exclusively of antimatter to be detected. The observation experiment's results are the first step towards an antihydrogen spectroscopy experiment which would measure the n = 2 Lamb shift and fine structure.
Einstein Toolkit for Relativistic Astrophysics
Collaborative Effort
2011-02-01
The Einstein Toolkit is a collection of software components and tools for simulating and analyzing general relativistic astrophysical systems. Such systems include gravitational wave space-times, collisions of compact objects such as black holes or neutron stars, accretion onto compact objects, core collapse supernovae and Gamma-Ray Bursts. The Einstein Toolkit builds on numerous software efforts in the numerical relativity community including CactusEinstein, Whisky, and Carpet. The Einstein Toolkit currently uses the Cactus Framework as the underlying computational infrastructure that provides large-scale parallelization, general computational components, and a model for collaborative, portable code development.
Density perturbations with relativistic thermodynamics
Maartens, R
1997-01-01
We investigate cosmological density perturbations in a covariant and gauge- invariant formalism, incorporating relativistic causal thermodynamics to give a self-consistent description. The gradient of density inhomogeneities splits covariantly into a scalar part, a rotational vector part that is determined by the vorticity, and a tensor part that describes the shape. We give the evolution equations for these parts in the general dissipative case. Causal thermodynamics gives evolution equations for viswcous stress and heat flux, which are coupled to the density perturbation equation and to the entropy and temperature perturbation equations. We give the full coupled system in the general dissipative case, and simplify the system in certain cases.
Thermodynamics of polarized relativistic matter
Kovtun, Pavel
2016-07-01
We give the free energy of equilibrium relativistic matter subject to external gravitational and electromagnetic fields, to one-derivative order in the gradients of the external fields. The free energy allows for a straightforward derivation of bound currents and bound momenta in equilibrium. At leading order, the energy-momentum tensor admits a simple expression in terms of the polarization tensor. Beyond the leading order, electric and magnetic polarization vectors are intrinsically ambiguous. The physical effects of polarization, such as the correlation between the magneto-vortically induced surface charge and the electro-vortically induced surface current, are not ambiguous.
Thermodynamics of polarized relativistic matter
Kovtun, Pavel
2016-01-01
We give the free energy of equilibrium relativistic matter subject to external gravitational and electromagnetic fields, to one-derivative order in the gradients of the external fields. The free energy allows for a straightforward derivation of bound currents and bound momenta in equilibrium. At leading order, the energy-momentum tensor admits a simple expression in terms of the polarization tensor. Beyond the leading order, electric and magnetic polarization vectors are intrinsically ambiguous. The physical effects of polarization, such as the correlation between the magneto-vortically induced surface charge and the electro-vortically induced surface current, are not ambiguous.
Relativistic solitons and superluminal signals
Energy Technology Data Exchange (ETDEWEB)
Maccari, Attilio [Technical Institute ' G. Cardano' , Piazza della Resistenza 1, Monterotondo, Rome 00015 (Italy)]. E-mail: solitone@yahoo.it
2005-02-01
Envelope solitons in the weakly nonlinear Klein-Gordon equation in 1 + 1 dimensions are investigated by the asymptotic perturbation (AP) method. Two different types of solitons are possible according to the properties of the dispersion relation. In the first case, solitons propagate with the group velocity (less than the light speed) of the carrier wave, on the contrary in the second case solitons always move with the group velocity of the carrier wave, but now this velocity is greater than the light speed. Superluminal signals are then possible in classical relativistic nonlinear field equations.
Optimal Design of Proposed 800 MeV Proton Cyclotron Beam Dynamics
Institute of Scientific and Technical Information of China (English)
YANG; Jian-jun; LI; Ming; ZHANG; Tian-jue; SONG; Guo-fang; AN; Shi-zhong
2015-01-01
The high intensity beam dynamic simulation shows that the theoretic beam current limit of the original design version of the 800 MeV proton cyclotron CYCIEA-800is 1mA.In order to further improve the current limit and reduce beam losses in the cyclotron,the layout of the cyclotron
Higher harmonic emission by a relativistic electron beam in a longitudinal magnetic wiggler
Davidson, Ronald C.; McMullin, Wayne A.
1982-10-01
The classical limit of the Einstein-coefficient method is used in the low-gain regime to calculate the stimulated emission from a tenuous relativistic electron beam propagating in the combined solenoidal and longitudinal wiggler fields (B0+δB k0z)e^z produced near the axis of a multiple-mirror (undulator) field configuration. Emission is found to occur at all harmonics of the wiggler wave number k0 with Doppler upshifted output frequency given by ω=(lk0Vb+ωcb)(1+Vbc)γ2b(1+γ2bV2⊥c2), where l>=1. The emission is compared to the low-gain cyclotron maser with δB=0 and to the low-gain free-electron laser (operating at higher harmonics) utilizing a transverse linearly polarized wiggler field.
Relativistic suppression of wave packet spreading.
Su, Q; Smetanko, B; Grobe, R
1998-03-30
We investigate numerically the solution of Dirac equation and analytically the Klein-Gordon equation and discuss the relativistic motion of an electron wave packet in the presence of an intense static electric field. In contrast to the predictions of the (non-relativistic) Schroedinger theory, the spreading rate in the field's polarization direction as well as in the transverse directions is reduced.
Magnetism and rotation in relativistic field theory
Mameda, Kazuya; Yamamoto, Arata
2016-09-01
We investigate the analogy between magnetism and rotation in relativistic theory. In nonrelativistic theory, the exact correspondence between magnetism and rotation is established in the presence of an external trapping potential. Based on this, we analyze relativistic rotation under external trapping potentials. A Landau-like quantization is obtained by considering an energy-dependent potential.
Relativistic heavy-ion physics: Experimental overview
Indian Academy of Sciences (India)
Itzhak Tserruya
2003-04-01
The ﬁeld of relativistic heavy-ion physics is reviewed with emphasis on new results and highlights from the ﬁrst run of the relativistic heavy-ion collider at BNL and the 15 year research programme at the super proton synchrotron (SPS) at CERN and the AGS at BNL.
Physico-mathematical foundations of relativistic cosmology
Soares, Domingos
2013-01-01
I briefly present the foundations of relativistic cosmology, which are, General Relativity Theory and the Cosmological Principle. I discuss some relativistic models, namely, "Einstein static universe" and "Friedmann universes". The classical bibliographic references for the relevant tensorial demonstrations are indicated whenever necessary, although the calculations themselves are not shown.
Einstein Never Approved of Relativistic Mass
Hecht, Eugene
2009-01-01
During much of the 20th century it was widely believed that one of the significant insights of special relativity was "relativistic mass." Today there are two schools on that issue: the traditional view that embraces speed-dependent "relativistic mass," and the more modern position that rejects it, maintaining that there is only one mass and it's…
General relativistic Boltzmann equation, I: Covariant treatment
Debbasch, F.; van Leeuwen, W.A.
2009-01-01
This series of two articles aims at dissipating the rather dense haze existing in the present literature around the General Relativistic Boltzmann equation. In this first article, the general relativistic one-particle distribution function in phase space is defined as an average of delta functions.
Critique of Conventional Relativistic Quantum Mechanics.
Fanchi, John R.
1981-01-01
Following an historical sketch of the development of relativistic quantum mechanics, a discussion of the still unresolved difficulties of the currently accepted theories is presented. This review is designed to complement and update the discussion of relativistic quantum mechanics presented in many texts used in college physics courses. (Author/SK)
Lattice Boltzmann equation for relativistic quantum mechanics.
Succi, Sauro
2002-03-15
Relativistic versions of the quantum lattice Boltzmann equation are discussed. It is shown that the inclusion of nonlinear interactions requires the standard collision operator to be replaced by a pair of dynamic fields coupling to the relativistic wave function in a way which can be described by a multicomponent complex lattice Boltzmann equation.
Relativistic corrections to molecular dynamic dipole polarizabilities
DEFF Research Database (Denmark)
Kirpekar, Sheela; Oddershede, Jens; Jensen, Hans Jørgen Aagaard
1995-01-01
Using response function methods we report calculations of the dynamic isotropic polarizability of SnH4 and PbH4 and of the relativistic corrections to it in the random phase approximation and at the correlated multiconfigurational linear response level of approximation. All relativistic corrections...
Energy Technology Data Exchange (ETDEWEB)
Mascali, David, E-mail: davidmascali@lns.infn.it; Castro, Giuseppe; Celona, Luigi; Neri, Lorenzo; Gammino, Santo [INFN–Laboratori Nazionali del Sud, Via S. Sofia 62, 95125 Catania (Italy); Biri, Sándor; Rácz, Richárd; Pálinkás, József [Institute for Nuclear Research (Atomki), Hungarian Academy of Sciences, Bem tér 18/c, H-4026 Debrecen (Hungary); Caliri, Claudia [INFN–Laboratori Nazionali del Sud, Via S. Sofia 62, 95125 Catania (Italy); Università degli Studi di Catania, Dip.to di Fisica e Astronomia, via Santa Sofia 64, 95123 Catania (Italy); Romano, Francesco Paolo [INFN–Laboratori Nazionali del Sud, Via S. Sofia 62, 95125 Catania (Italy); CNR, Istituto per i Beni Archeologici e Monumentali, Via Biblioteca 4, 95124 Catania (Italy); Torrisi, Giuseppe [INFN–Laboratori Nazionali del Sud, Via S. Sofia 62, 95125 Catania (Italy); Università Mediterranea di Reggio Calabria, DIIES, Via Graziella, I-89100 Reggio Calabria (Italy)
2016-02-15
An experimental campaign aiming to investigate electron cyclotron resonance (ECR) plasma X-ray emission has been recently carried out at the ECRISs—Electron Cyclotron Resonance Ion Sources laboratory of Atomki based on a collaboration between the Debrecen and Catania ECR teams. In a first series, the X-ray spectroscopy was performed through silicon drift detectors and high purity germanium detectors, characterizing the volumetric plasma emission. The on-purpose developed collimation system was suitable for direct plasma density evaluation, performed “on-line” during beam extraction and charge state distribution characterization. A campaign for correlating the plasma density and temperature with the output charge states and the beam intensity for different pumping wave frequencies, different magnetic field profiles, and single-gas/gas-mixing configurations was carried out. The results reveal a surprisingly very good agreement between warm-electron density fluctuations, output beam currents, and the calculated electromagnetic modal density of the plasma chamber. A charge-coupled device camera coupled to a small pin-hole allowing X-ray imaging was installed and numerous X-ray photos were taken in order to study the peculiarities of the ECRIS plasma structure.
Hollweg, J. V.; Markovskii, S. A.
2001-05-01
UVCS/SOHO has provided observations of protons and ions in coronal holes which suggest the operation of ion-cyclotron heating and acceleration. Many models have concentrated on the interactions of particles with parallel-propagating ion-cyclotron waves. There is of course no reason to expect parallel propagation in the corona, so we consider here some consequences of oblique propagation. Following Stix (1992), we analytically calculate the energy absorbed by an ion moving in an obliquely-propagating electromagnetic wave. Resonances occur at harmonics of the gyro frequency, though we will show that the physical interpretations are quite different for electric field polarizations in, or perpendicular to, the plane containing k and Bo (k is wavenumber and Bo is the ambient magnetic field). Surprisingly, a resonance at the fundamental frequency can occur even if the wave is right-hand circularly polarized (i.e. opposite to the sense of the gyromotion). We suggest, therefore, that resonances with the fast/whistler branch, which are often overlooked, may play a role in the heating of ions and protons in coronal holes as long as the waves are oblique. We will discuss possible sources of such waves. We will also summarize other consequences of oblique propagation for the resonant heating of coronal holes and the origin of the fast solar wind. Stix, T.H., Waves in Plasmas, AIP, New York, 1992.
The surprising diversity of clostridial hydrogenases: a comparative genomic perspective.
Calusinska, Magdalena; Happe, Thomas; Joris, Bernard; Wilmotte, Annick
2010-06-01
Among the large variety of micro-organisms capable of fermentative hydrogen production, strict anaerobes such as members of the genus Clostridium are the most widely studied. They can produce hydrogen by a reversible reduction of protons accumulated during fermentation to dihydrogen, a reaction which is catalysed by hydrogenases. Sequenced genomes provide completely new insights into the diversity of clostridial hydrogenases. Building on previous reports, we found that [FeFe] hydrogenases are not a homogeneous group of enzymes, but exist in multiple forms with different modular structures and are especially abundant in members of the genus Clostridium. This unusual diversity seems to support the central role of hydrogenases in cell metabolism. In particular, the presence of multiple putative operons encoding multisubunit [FeFe] hydrogenases highlights the fact that hydrogen metabolism is very complex in this genus. In contrast with [FeFe] hydrogenases, their [NiFe] hydrogenase counterparts, widely represented in other bacteria and archaea, are found in only a few clostridial species. Surprisingly, a heteromultimeric Ech hydrogenase, known to be an energy-converting [NiFe] hydrogenase and previously described only in methanogenic archaea and some sulfur-reducing bacteria, was found to be encoded by the genomes of four cellulolytic strains: Clostridum cellulolyticum, Clostridum papyrosolvens, Clostridum thermocellum and Clostridum phytofermentans.
Atom Surprise: Using Theatre in Primary Science Education
Peleg, Ran; Baram-Tsabari, Ayelet
2011-10-01
Early exposure to science may have a lifelong effect on children's attitudes towards science and their motivation to learn science in later life. Out-of-class environments can play a significant role in creating favourable attitudes, while contributing to conceptual learning. Educational science theatre is one form of an out-of-class environment, which has received little research attention. This study aims to describe affective and cognitive learning outcomes of watching such a play and to point to connections between theatrical elements and specific outcomes. "Atom Surprise" is a play portraying several concepts on the topic of matter. A mixed methods approach was adopted to investigate the knowledge and attitudes of children (grades 1-6) from two different school settings who watched the play. Data were gathered using questionnaires and in-depth interviews. Analysis suggested that in both schools children's knowledge on the topic of matter increased after the play with younger children gaining more conceptual knowledge than their older peers. In the public school girls showed greater gains in conceptual knowledge than boys. No significant changes in students' general attitudes towards science were found, however, students demonstrated positive changes towards science learning. Theatrical elements that seemed to be important in children's recollection of the play were the narrative, props and stage effects, and characters. In the children's memory, science was intertwined with the theatrical elements. Nonetheless, children could distinguish well between scientific facts and the fictive narrative.
Novelty biases attention and gaze in a surprise trial.
Horstmann, Gernot; Herwig, Arvid
2016-01-01
While the classical distinction between task-driven and stimulus-driven biasing of attention appears to be a dichotomy at first sight, there seems to be a third category that depends on the contrast or discrepancy between active representations and the upcoming stimulus, and may be termed novelty, surprise, or prediction failure. For previous demonstrations of the discrepancy-attention link, stimulus-driven components (saliency) may have played a decisive role. The present study was conducted to evaluate the discrepancy-attention link in a display where novel and familiar stimuli are equated for saliency. Eye tracking was used to determine fixations on novel and familiar stimuli as a proxy for attention. Results show a prioritization of attention by the novel color, and a de-prioritization of the familiar color, which is clearly present at the second fixation, and spans over the next couple of fixations. Saliency, on the other hand, did not prioritize items in the display. The results thus reinforce the notion that novelty captures and binds attention.
A Well-Known But Still Surprising Generator
Haugland, Ole Anton
2014-12-01
The bicycle generator is often mentioned as an example of a method to produce electric energy. It is cheap and easily accessible, so it is a natural example to use in teaching. There are different types, but I prefer the old side-wall dynamo. The most common explanation of its working principle seems to be something like the illustration in Fig. 1. The illustration is taken from a popular textbook in the Norwegian junior high school.1 Typically it is explained as a system of a moving magnet or coils that directly results in a varying magnetic field through the coils. According to Faraday's law a voltage is induced in the coils. Simple and easy! A few times I have had a chance to glimpse into a bicycle generator, and I was somewhat surprised to sense that the magnet rotated parallel to the turns of the coil. How could the flux through the coil change and induce a voltage when the magnet rotated parallel to the turns of the coil? When teaching electromagnetic induction I have showed the students a dismantled generator and asked them how this could work. They naturally found that this was more difficult to understand than the principle illustrated in Fig. 1. Other authors in this journal have discussed even more challenging questions concerning electric generators.2,3
Magnetic Sublevel Population Studied for H- and He-like Uranium in Relativistic Ion-Atom Collisions
Energy Technology Data Exchange (ETDEWEB)
Gumberidze, A.; Stoehlker, T. [GSI-Darmstadt (Germany); Bednarz, G. [Cracow University, Institute of Physics (Poland); Bosch, F. [GSI-Darmstadt (Germany); Fritzsche, S. [University of Kassel (Germany); Hagmann, S. [Kansas State University (United States); Ionescu, D. C.; Klepper, O.; Kozhuharov, C.; Kraemer, A.; Liesen, D.; Ma, X.; Mann, R.; Mokler, P. H. [GSI-Darmstadt (Germany); Sierpowski, D. [Cracow University, Institute of Physics (Poland); Stachura, Z. [INP (Poland); Steck, M.; Toleikis, S. [GSI-Darmstadt (Germany); Warczak, A. [Cracow University, Institute of Physics (Poland)
2003-03-15
An experimental study for K-shell excitation of helium-like uranium in relativistic collisions with low-Z gaseous target is presented. Within this experiment information about the population of the magnetic sublevels has been obtained via a photon angular differential study of the decay photons associated with the excitation process. The preliminary results presented show, for the particular case of the {sup 3}P{sub 1} level, a surprisingly strong population of the magnetic sublevels with {mu}={+-}1.
Relativistic electron beams above thunderclouds
Directory of Open Access Journals (Sweden)
M. Füllekrug
2011-08-01
Full Text Available Non-luminous relativistic electron beams above thunderclouds have been detected by the radio signals of low frequency ∼40–400 kHz which they radiate. The electron beams occur ∼2–9 ms after positive cloud-to-ground lightning discharges at heights between ∼22–72 km above thunderclouds. Intense positive lightning discharges can also cause sprites which occur either above or prior to the electron beam. One electron beam was detected without any luminous sprite which suggests that electron beams may also occur independently of sprites. Numerical simulations show that beams of electrons partially discharge the lightning electric field above thunderclouds and thereby gain a mean energy of ∼7 MeV to transport a total charge of ∼−10 mC upwards. The impulsive current ∼3 × 10^{−3} Am^{−2} associated with relativistic electron beams above thunderclouds is directed downwards and needs to be considered as a novel element of the global atmospheric electric circuit.
Ponderomotive Acceleration by Relativistic Waves
Lau, Calvin; Yeh, Po-Chun; Luk, Onnie; McClenaghan, Joseph; Ebisuzaki, Toshikazu; Tajima, Toshiki
2014-01-01
In the extreme high intensity regime of electromagnetic (EM) waves in plasma, the acceleration process is found to be dominated by the ponderomotive acceleration (PA). While the wakefields driven by the ponderomotive force of the relativistic intensity EM waves are important, they may be overtaken by the PA itself in the extreme high intensity regime when the dimensionless vector potential $a_0$ of the EM waves far exceeds unity. The energy gain by this regime (in 1D) is shown to be (approximately) proportional to $a_0^2$. Before reaching this extreme regime, the coexistence of the PA and the wakefield acceleration (WA) is observed where the wave structures driven by the wakefields show the phenomenon of multiple and folded wave-breakings. Investigated are various signatures of the acceleration processes such as the dependence on the mass ratio for the energy gain as well as the energy spectral features. The relevance to high energy cosmic ray acceleration and to the relativistic laser acceleration is conside...
24-Hour Relativistic Bit Commitment
Verbanis, Ephanielle; Martin, Anthony; Houlmann, Raphaël; Boso, Gianluca; Bussières, Félix; Zbinden, Hugo
2016-09-01
Bit commitment is a fundamental cryptographic primitive in which a party wishes to commit a secret bit to another party. Perfect security between mistrustful parties is unfortunately impossible to achieve through the asynchronous exchange of classical and quantum messages. Perfect security can nonetheless be achieved if each party splits into two agents exchanging classical information at times and locations satisfying strict relativistic constraints. A relativistic multiround protocol to achieve this was previously proposed and used to implement a 2-millisecond commitment time. Much longer durations were initially thought to be insecure, but recent theoretical progress showed that this is not so. In this Letter, we report on the implementation of a 24-hour bit commitment solely based on timed high-speed optical communication and fast data processing, with all agents located within the city of Geneva. This duration is more than 6 orders of magnitude longer than before, and we argue that it could be extended to one year and allow much more flexibility on the locations of the agents. Our implementation offers a practical and viable solution for use in applications such as digital signatures, secure voting and honesty-preserving auctions.
Chaos and Maps in Relativistic Dynamical Systems
Horwitz, L P
1999-01-01
The basic work of Zaslavskii et al showed that the classical non-relativistic electromagnetically kicked oscillator can be cast into the form of an iterative map on the phase space; the resulting evolution contains a stochastic flow to unbounded energy. Subsequent studies have formulated the problem in terms of a relativistic charged particle in interaction with the electromagnetic field. We review the structure of the covariant Lorentz force used to study this problem. We show that the Lorentz force equation can be derived as well from the manifestly covariant mechanics of Stueckelberg in the presence of a standard Maxwell field, establishing a connection between these equations and mass shell constraints. We argue that these relativistic generalizations of the problem are intrinsically inaccurate due to an inconsistency in the structure of the relativistic Lorentz force, and show that a reformulation of the relativistic problem, permitting variations (classically) in both the particle mass and the effective...
Relativistic Particles in Clusters of Galaxies
Ensslin, T A
2002-01-01
A brief overview on the theory and observations of relativistic particle populations in clusters of galaxies is given. The following topics are addressed: (i) the diffuse relativistic electron population within the intra-cluster medium (ICM) as seen in the cluster wide radio halos and possibly also seen in the high energy X-ray and extreme ultraviolet excess emissions of some clusters, (ii) the observed confined relativistic electrons within fresh and old radio plasma and their connection to cluster radio relics at cluster merger shock waves, (iii) the relativistic proton population within the ICM, and its observable consequences (if it exists), and (iv) the confined relativistic proton population (if it exists) within radio plasma. The importance of upcoming, sensitive gamma-ray telescopes for this research area is highlighted.
Relativistic gas in a Schwarzschild metric
Kremer, Gilberto M
2013-01-01
A relativistic gas in a Schwarzschild metric is studied within the framework of a relativistic Boltzmann equation in the presence of gravitational fields, where Marle's model for the collision operator of the Boltzmann equation is employed. The transport coefficients of bulk and shear viscosities and thermal conductivity are determined from the Chapman-Enskog method. It is shown that the transport coefficients depend on the gravitational potential. Expressions for the transport coefficients in the presence of weak gravitational fields in the non-relativistic (low temperatures) and ultra-relativistic (high temperatures) limiting cases are given. Apart from the temperature gradient the heat flux has two relativistic terms. The first one, proposed by Eckart, is due to the inertia of energy and represents an isothermal heat flux when matter is accelerated. The other, suggested by Tolman, is proportional to the gravitational potential gradient and indicates that -- in the absence of an acceleration field -- a stat...
Relativistic recursion relations for transition matrix elements
Martínez y Romero, R P; Salas-Brito, A L
2004-01-01
We review some recent results on recursion relations which help evaluating arbitrary non-diagonal, radial hydrogenic matrix elements of $r^\\lambda$ and of $\\beta r^\\lambda$ ($\\beta$ a Dirac matrix) derived in the context of Dirac relativistic quantum mechanics. Similar recursion relations were derived some years ago by Blanchard in the non relativistic limit. Our approach is based on a generalization of the second hypervirial method previously employed in the non-relativistic Schr\\"odinger case. An extension of the relations to the case of two potentials in the so-called unshifted case, but using an arbitrary radial function instead of a power one, is also given. Several important results are obtained as special instances of our recurrence relations, such as a generalization to the relativistic case of the Pasternack-Sternheimer rule. Our results are useful in any atomic or molecular calculation which take into account relativistic corrections.
Surprise disrupts cognition via a fronto-basal ganglia suppressive mechanism.
Wessel, Jan R; Jenkinson, Ned; Brittain, John-Stuart; Voets, Sarah H E M; Aziz, Tipu Z; Aron, Adam R
2016-04-18
Surprising events markedly affect behaviour and cognition, yet the underlying mechanism is unclear. Surprise recruits a brain mechanism that globally suppresses motor activity, ostensibly via the subthalamic nucleus (STN) of the basal ganglia. Here, we tested whether this suppressive mechanism extends beyond skeletomotor suppression and also affects cognition (here, verbal working memory, WM). We recorded scalp-EEG (electrophysiology) in healthy participants and STN local field potentials in Parkinson's patients during a task in which surprise disrupted WM. For scalp-EEG, surprising events engage the same independent neural signal component that indexes action stopping in a stop-signal task. Importantly, the degree of this recruitment mediates surprise-related WM decrements. Intracranially, STN activity is also increased post surprise, especially when WM is interrupted. These results suggest that surprise interrupts cognition via the same fronto-basal ganglia mechanism that interrupts action. This motivates a new neural theory of how cognition is interrupted, and how distraction arises after surprising events.
Fokker-Planck Study of Tokamak Electron Cyclotron Resonance Heating
Institute of Scientific and Technical Information of China (English)
SHIBingren; LONGYongxing; DONGJiaqi; LIWenzhong; JIAOYiming; WANGAike
2002-01-01
In this study, we add a subroutine for describing the electron cyclotron resonant heating calculation to the Fokker-Planck code. By analyzing the wave-particle resonance condition in tokamak plasma and the fast motion of electrons along magnetic field lines, suitable quasi-linear diffusion coefficients are given.
Electron cyclotron heating and current drive in toroidal geometry
Energy Technology Data Exchange (ETDEWEB)
Kritz, A.H.
1991-11-01
The Principal Investigator has continued to work on problems associated both with the deposition and with the emission of electron cyclotron power in toroidal plasmas. We have investigated the use of electron cyclotron resonance heating for bringing compact tokamaks (BPX) to ignition-like parameters. This requires that we continue to refine the modeling capability of the TORCH code linked with the BALDUR 1 {1/2} D transport code. Using this computational tool, we have examined the dependence of ignition on heating and transport employing both theoretical (multi-mode) and empirically based transport models. The work on current drive focused on the suppression of tearing modes near the q = 2 surface and sawteeth near the q = 1 surface. Electron cyclotron current drive in CIT near the q =2 surface was evaluated for a launch scenario where electron cyclotron power was launched near the equatorial plane. The work on suppression of sawteeth has been oriented toward understanding the suppression that has been observed in a number of tokamaks, in particular, in the WT-3 tokamak in Kyoto. To evaluate the changes in current profile (shear) near the q =1 surface, simulations have been carried out using the linked BALDUR-TORCH code. We consider effects on shear resulting both from wave-induced current as well as from changes in conductivity associated with changes in local temperature. Abstracts and a paper relating to this work is included in Appendix A.
Beam phase measurement in the AGOR-cyclotron
Brandenburg, S; Roobol, LP; Schreuder, HW; de Vries, L; Laune, B; Baron, E.; Lieuvin, M.
1999-01-01
The AGOR cyclotron is equipped with thirteen phase probes for optimization of the isochronism The beam phase is measured at the 2(nd) harmonic of the RF frequency, in order to be able to suppress the large RF interference from the nearby resonators. At low RF frequencies a phase accuracy of 1 deg. i
Traveling wave ion transport for the cyclotron gas stopper
Energy Technology Data Exchange (ETDEWEB)
Brodeur, M., E-mail: maxime.brodeur.2@nd.edu; Joshi, N.; Gehring, A.E.; Bollen, G.; Morrissey, D.J.; Schwarz, S.
2013-12-15
Highlights: • Estimated transport time of thermal ions of 5 ms or less for the cyclotron gas stopper using the ion surfing method. • Experimental investigation of a prototype ion conveyor to transport ions in the magnet magnetic field gradient. • Efficient long-distance ion transport with the conveyor is expected. -- Abstract: Next generation beam thermalization devices such as the cyclotron gas stopper are being developed to efficiently deliver a broad range of radioactive isotopes to experiments. Ion transport methods utilizing a traveling wave were investigated experimentally as part of the developments needed for this device. The “ion surfing” method, which will be used to transports thermal ions inside the main chamber of the cyclotron gas stopper, was found to transport ions at speeds reaching 75 m/s, resulting in net transport times as short as 5 ms. A second traveling wave transport method called the “ion conveyor” was investigated for the challenging task of extracting the ions through the cyclotron gas stopper magnetic field gradient. Results from the first prototype conveyor show a strong pressure and wave amplitude dependance for the transport efficiency. A second prototype designed to operate over a larger pressure range is currently being tested.
Cyclotron waves in a non-neutral plasma column
Energy Technology Data Exchange (ETDEWEB)
Dubin, Daniel H. E. [Department of Physics, University of California at San Diego, La Jolla, California 92093 (United States)
2013-04-15
A kinetic theory of linear electrostatic plasma waves with frequencies near the cyclotron frequency {Omega}{sub c{sub s}} of a given plasma species s is developed for a multispecies non-neutral plasma column with general radial density and electric field profiles. Terms in the perturbed distribution function up to O(1/{Omega}{sub c{sub s}{sup 2}}) are kept, as are the effects of finite cyclotron radius r{sub c} up to O(r{sub c}{sup 2}). At this order, the equilibrium distribution is not Maxwellian if the plasma temperature or rotation frequency is not uniform. For r{sub c}{yields}0, the theory reproduces cold-fluid theory and predicts surface cyclotron waves propagating azimuthally. For finite r{sub c}, the wave equation predicts that the surface wave couples to radially and azimuthally propagating Bernstein waves, at locations where the wave frequency equals the local upper hybrid frequency. The equation also predicts a second set of Bernstein waves that do not couple to the surface wave, and therefore have no effect on the external potential. The wave equation is solved both numerically and analytically in the WKB approximation, and analytic dispersion relations for the waves are obtained. The theory predicts that both types of Bernstein wave are damped at resonances, which are locations where the Doppler-shifted wave frequency matches the local cyclotron frequency as seen in the rotating frame.
Vacuum Pre-designing for CYCIAE-230 Superconducting Cyclotron
Institute of Scientific and Technical Information of China (English)
ZHANG; Su-ping; PAN; Gao-feng; LI; Zhen-guo; QIN; Jiu-chang
2015-01-01
CYCIAE-230superconducting cyclotron has two separate vacuum system,one is for beam chamber,another is for cryostat.Beam chamber and cryostat shall maintain separate vacuum against atmospheric pressure.The pressure of pumps inlet is better than 1×10-4Pa and the
Digital control in LLRF system for CYCIAE-100 cyclotron
Energy Technology Data Exchange (ETDEWEB)
Yin, Zhiguo, E-mail: bitbearAT@hotmail.com; Fu, Xiaoliang; Ji, Bin; Zhang, Tianjue; Wang, Chuan
2016-05-21
As a driven accelerator, the CYCIAE-100 cyclotron is designed by China Institute of Atomic Energy for the Beijing Radio Ion-beam Facility project. The cyclotron RF system is designed to use two RF power sources of 100 kW to drive two half-wavelength cavities respectively. Two Dee accelerating electrodes are kept separately from each other inside the cyclotron, while their accelerating voltages are maintained in phase by the efforts of LLRF control. An analog–digital hybrid LLRF system has been developed to achieve cavity tuning control, dee voltage amplitude and phase stabilization etc. The analog subsystems designs are focused on RF signal up/down conversion, tuning control, and dee voltage regulation. The digital system provides an RF signal source, aligns the cavity phases and maintains a Finite State Machine. The digital parts combine with the analog functions to provide the LLRF control. A brief system hardware introduction will be given in this paper, followed by the review of several major characteristics of the digital control in the 100 MeV cyclotron LLRF system. The commissioning is also introduced, and most of the optimization during the process was done by changing the digital parts.
Ion-Beam-Excited Electrostatic Ion Cyclotron Instability
DEFF Research Database (Denmark)
Michelsen, Poul; Pécseli, Hans; Juul Rasmussen, Jens
1977-01-01
The stability limits of the ion‐beam‐excited, electrostatic, ion cyclotron instability were investigated in a Q‐machine plasma where the electrons could be heated by microwaves. In agreement with theory, the beam energy necessary for excitation decreased with increasing electron temperature....
Unstable Electrostatic Ion Cyclotron Waves Exited by an Ion Beam
DEFF Research Database (Denmark)
Michelsen, Poul; Pécseli, Hans; Juul Rasmussen, Jens
1976-01-01
Electrostatic ion cyclotron waves were observed in a quiescent cesium plasma into which a low‐energy beam of sodium ions was injected. The instability appeared when the beam velocity was above 12 times the ion thermal velocity. The waves propagated along the magnetic field with a velocity somewhat...
Cyclotrons with Fast Variable and/or Multiple Energy Extraction
Baumgarten, C
2013-01-01
We discuss the principle possibility of stripping extraction in combination with reverse bends in isochronous separate sector cyclotrons (and/or FFAGs). If one uses reverse bends between the sectors (instead of drifts) and places stripper foils at the sector exit edges, the stripped beam has a reduced bending radius and it should be able to leave the cyclotron within the range of the reverse bend - even if the beam is stripped at less than full energy. We are especially interested in $H_2^+$-cyclotrons, which allow to double the charge to mass ratio by stripping. However the principle could be applied to other ions or ionized molecules as well. For the production of proton beams by stripping extraction of an $H_2^+$-beam, we discuss possible designs for three types of machines: First a low-energy cyclotron for the simultaneous production of several beams at multiple energies - for instance 15 MeV, 30 MeV and 70 MeV - thus allowing to have beam on several isotope production targets. In this case it is desired ...
Radiation safety aspects of the AGOR superconducting cyclotron facility
Beijers, JPM; de Meijer, RJ
1996-01-01
This paper describes shielding calculations and skyshine estimates for the new AGOR K=600 superconducting cyclotron facility. Both simple, semi-empirical models and Monte-Carlo simulations were used. The calculations are based on a 200 MeV proton beam incident on a trick aluminum target. Also the
Heavy stable isotope separation by ion cyclotron resonance
Energy Technology Data Exchange (ETDEWEB)
Louvet, P.; Compant La Fontaine, A.; Larousse, B.; Patris, M.
1994-12-31
The scientific feasibility of the ion cyclotron resonance process (ICR), as well as the technical one, has been investigated carefully for light metallic elements, whose masses lies between 40 and 100/1,2/. The present work deals mainly with the same demonstration for heavier elements such as ytterbium, gadolinium and barium. Recent results, as well as future prospects, are considered here. (authors).
The development of technology for the improvement of cyclotron performance
Energy Technology Data Exchange (ETDEWEB)
Chai, Jong Seo; Kim, Y. S.; Ha, J. H.; Lee, M. Y.; Lee, H. S
1999-05-01
We show the first-order beam optics theory which is a simplified theory that can be used to carry out the initial design of a cyclotron. Based on this, a computer program has been developed to determine main cyclotron parameters such as number of magnet sectors, sector angle, hill and valley fields, and overall size of the cyclotron etc. We then show the result of two-dimensional magnetic field calculation using POISSON program. By using this program, one can determine magnet yoke geometry and the average magnetic fields etc. Finally, the three-dimensional computer program OPERA-3D had been invoked to determine magnet pole tips (i.e. sector). Validity of the design can be seen by investigating magnetic fields, radial and vertical focusing frequencies as a function of the beam energy. In this report, we show the results of cyclotron magnet design. And we designed 72 MHz RF system and ion source system. We tested RF resonance each coupling methods. We show the result of RF design and prototype operation. Our developed ion source is PIG type. We described our design methods and implementation. We report the result of getting negative hydrogen ion.
A new RF system for a rejuvenated Synchro-cyclotron
1975-01-01
The Synchro-cyclotron is shown here shortly after the completion of the improvement programme, which left the steel magnet yoke as almost the only remaining component of the original machine. On the left can be seen the rotary condenser which produces the frequency modulation required for the acceleration (one of a pair available -in this instance ROTCO II). (see photo 7506015)
Radiation safety aspects of the AGOR superconducting cyclotron facility
Beijers, JPM; de Meijer, RJ
1996-01-01
This paper describes shielding calculations and skyshine estimates for the new AGOR K=600 superconducting cyclotron facility. Both simple, semi-empirical models and Monte-Carlo simulations were used. The calculations are based on a 200 MeV proton beam incident on a trick aluminum target. Also the de
Asymmetric Wave Transmission During Electron-Cyclotron Resonant Heating
Peeters, A.G.; Smits, F. M. A.; Giruzzi, G.; Oomens, A. A. M.; Westerhof, E.
1995-01-01
In low density plasmas in the RTP tokamak the single-pass absorption of O-mode waves at the fundamental electron cyclotron resonance is observed to be toroidally asymmetric. The absorption is highest for waves travelling in the direction opposite to the toroidal plasma current. Fokker-Planck
THE DEMINERALIZED WATER SYSTEM FOR THE NRL CYCLOTRON.
handling system was considered impractical to handle this heat load. Therefore, the demineralized water system for the NRL Sector-Focusing Cyclotron...decided to run the water system on a continuous basis. Continuous operation can be dangerous, because it can cause a large leak to occur, but this
Ion-Beam-Excited, Electrostatic, Ion Cyclotron Instability
DEFF Research Database (Denmark)
Michelsen, Poul; Pécseli, Hans; Juul Rasmussen, Jens
1977-01-01
The stability limits of the ion‐beam‐excited, electrostatic, ion cyclotron instability were investigated in a Q‐machine plasma where the electrons could be heated by microwaves. In agreement with theory, the beam energy necessary for excitation decreased with increasing electron temperature....
Development of beam instruments at JAERI cyclotron facility
Energy Technology Data Exchange (ETDEWEB)
Okumura, Susumu; Fukuda, Mitsuhiro; Ishibori, Ikuo; Agematsu, Takashi; Yokota, Watalu; Nara, Takayuki; Nakamura, Yoshiteru; Arakawa, Kazuo [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment
1997-03-01
A beam phase monitor and two kinds of fluence distribution monitors have been developed for measuring characteristics of cyclotron beams. The beam phase monitor provides a beam phase signal for tuning a beam chopping system and a beam phase selection system. A two-dimensional fluence distribution on a large area is measured with fluence distribution monitors. (author)
Maryland University sectored isochronous cyclotron (MUSIC): Progress report No. 35
Energy Technology Data Exchange (ETDEWEB)
1986-10-29
Efforts are reported on the installation and checkout of cyclotron components which had been previously fabricated. Final integration of subsystems and major systems leading to internal beam tests is reported near completion. Progress is reported in relation to control system components, focus and steering magnet design, and rf system testing. (LEW)
Digital control in LLRF system for CYCIAE-100 cyclotron
Yin, Zhiguo; Fu, Xiaoliang; Ji, Bin; Zhang, Tianjue; Wang, Chuan
2016-05-01
As a driven accelerator, the CYCIAE-100 cyclotron is designed by China Institute of Atomic Energy for the Beijing Radio Ion-beam Facility project. The cyclotron RF system is designed to use two RF power sources of 100 kW to drive two half-wavelength cavities respectively. Two Dee accelerating electrodes are kept separately from each other inside the cyclotron, while their accelerating voltages are maintained in phase by the efforts of LLRF control. An analog-digital hybrid LLRF system has been developed to achieve cavity tuning control, dee voltage amplitude and phase stabilization etc. The analog subsystems designs are focused on RF signal up/down conversion, tuning control, and dee voltage regulation. The digital system provides an RF signal source, aligns the cavity phases and maintains a Finite State Machine. The digital parts combine with the analog functions to provide the LLRF control. A brief system hardware introduction will be given in this paper, followed by the review of several major characteristics of the digital control in the 100 MeV cyclotron LLRF system. The commissioning is also introduced, and most of the optimization during the process was done by changing the digital parts.
Classical calculation of relativistic frequency-shifts in an ideal Penning trap
Ketter, Jochen; Höcker, Martin; Schuh, Marc; Streubel, Sebastian; Blaum, Klaus
2013-01-01
The ideal Penning trap consists of a uniform magnetic field and an electrostatic quadrupole potential. In the classical low-energy limit, the three characteristic eigenfrequencies of a charged particle trapped in this configuration do not depend on the amplitudes of the three eigenmotions. No matter how accurate the experimental realization of the ideal Penning trap, its harmonicity is ultimately compromised by special relativity. Using a classical formalism of first-order perturbation theory, we calculate the relativistic frequency-shifts associated with the motional degrees of freedom for a spinless particle stored in an ideal Penning trap, and we compare the results with the simple but surprisingly accurate model of relativistic mass-increase.
Certified Randomness from a Two-Level System in a Relativistic Quantum Field
Thinh, Le Phuc; Martin-Martinez, Eduardo
2016-01-01
Randomness is an indispensable resource in modern science and information technology. Fortunately, an experimentally simple procedure exists to generate randomness with well-characterized devices: measuring a quantum system in a basis complementary to its preparation. Towards realizing this goal one may consider using atoms or superconducting qubits, promising candidates for quantum information processing. However, their unavoidable interaction with the electromagnetic field affects their dynamics. At large time scales, this can result in decoherence. Smaller time scales in principle avoid this problem, but may not be well analysed under the usual rotating wave and single-mode approximation (RWA and SMA) which break the relativistic nature of quantum field theory. Here, we use a fully relativistic analysis to quantify the information that an adversary with access to the field could get on the result of an atomic measurement. Surprisingly, we find that the adversary's guessing probability is not minimized for ...
Institute of Scientific and Technical Information of China (English)
B.(I). GUL(I)YEV; R. F. EM(I)NBEYL(I); A. KORKUT
2007-01-01
The Fermi energy, cyclotron energy and cyclotron effective mass of degenerate electron gas in a size-quantized semiconductor thin film with non-parabolic energy bands are studied. The influences of quantizing magnetic field on these quantities in two-band approximation of the Kane model are investigated. It is shown that the Fermi energy oscillates in a magnetic field. The period and positions of these oscillations are found as a function of film thickness and concentration of electrons. Cyclotron energy and cyclotron effective mass are investigated as a function of film thickness in detail. The results obtained here are compared with experimental data on GaAs quantum wells.
Properties and Surprises of Solar Activity XXIII Cycle
Ishkov, V. N.
2010-12-01
The main properties of the 23rd cycle match almost completely those of average-magnitude solar cycles, and some of the features of the cycle may indicate a change in the generation mode of magnetic fields in the solar convection zone. If this is the case, the Sun enters a period of intermediate and weak cycles of solar activity (SA) in terms of the Wolf number, which may last for 3 to 6 solar cycles. The main development stages of solar cycle 23 are the following: minimum of solar cycle 22: April 1996 (W* = 8.0); maximum of the smoothed relative sunspot number: April 2000; global polarity reversal of the general solar magnetic field: July to December 2000; secondary maximum of the relative sunspot number: November 2001; maximum of the 10.7-cm radio flux: February 2002; phase of the cycle maximum: October 1999 to June 2002; beginning of the decrease phase: July 2002; the point of minimum of the current SA cycle: December 2008. Solar cycle 23 has presented two powerful flare-active sunspot groups, in September 2005 and December 2006 (+5.5 and +6.6 years from the maximum) which by flare potential occupy 4th and 20th place among the most flare-active regions for the last four solar cycles. The unprecedented duration of the relative sunspot numbers fall that has led to already record duration of the last solar cycle among authentic cycles (since 1849) became the next surprise of development of solar activity during the last cycle. The phase of the minimum began in May 2005 and lasted for 4.5 years. Thus, the new solar cycle 24 has begun in January 2009.
Dracunculiasis eradication - Finishing the job before surprises arise
Institute of Scientific and Technical Information of China (English)
Benjamin Jelle Visser
2012-01-01
ABSTRACT Dracunculiasis(Guinea worm disease) is a preventable waterborne parasitic disease that affects the poorest people living in remote rural areas in sub-SaharanAfrican countries, who do not have access to safe drinking water.The Guinea Worm Eradication Program, a25-year old campaign to rid the world ofGuineaWorm disease has now reached its final stage accelerating to zero cases in all endemic countries.During the19th and20th centuries, dracunculiasis was common in much ofSouthernAsia and theAfrican continent.The overall number of cases has been reduced tremendously by≥99%, from the3.32 million cases estimated to have occurred in1986 inAfrica to only1797 cases reported in2010 reported in only five countries(Sudan,Mali,Ethiopia,Chad andGhana) andAsia free of the disease.This achievement is unique in its kind - the only previously eradicated disease is smallpox, a viral infection for which vaccination was possible - and it has been achieved through primary community-based prevention and health education programs.Most efforts need to be taken in two countries,SouthSudan(comprising94% or1698 out of1797 of the cases reported world-wide in2010) andMali because of frequent movements of nomads in a vast area inside and outsideMali’s borders.All factors favourable to dracunculiasis eradication are available including adequate financial resources, community and political support and high levels of advocacy.Thus there is no reason that this disabling parasitic disease cannot be eradicated soon before surprises arise such as new civil conflicts in currently endemic countries.
Use of cyclotrons in medical research: Past, present, future
Smathers, James B.; Myers, Lee T.
1985-05-01
The use of cyclotrons in medical research started in the late 1930s with the most prominent use being neutron irradiation in cancer therapy. Due to a lack of understanding of the biological effect of neutrons, the results were less than encouraging. In the 1940s and 1950s, small cyclotrons were used for isotope production and in the mid 60s, the biological effect of neutrons was more thoroughly studied, with the result that a second trial of neutron therapy was initiated at Hammersmith Hospital, England. Concurrent with this, work on the use of high energy charged particles, initially protons and alphas, was initiated in Sweden and Russia and at Harvard and Berkeley. The English success in neutron therapy led to some pilot studies in the USA using physics cyclotrons of various energies and targets. These results in turn lead to the present series of machines presently being installed at M.D. Anderson Hospital (42 MeV), Seattle (50 MeV) and UCLA (46 MeV). The future probably bodes well for cyclotrons at the two extremes of the energy range. For nuclear medicine the shift is away from the use of multiple isotopes, which requires a large range of particles and energies to 11C, 13N, 15O, and 18F, which can be incorporated in metabolic specific compounds and be made with small 8-10 MeV p+ "table top" cyclotrons. For tumor therapy machines of 60 MeV or so will probably be the choice for the future, as they allow the treatment of deep seated tumors with neutrons and the charged particles have sufficient range to allow the treatment of ocular tumors.
Heavy ion cocktail beams at the 88 inch Cyclotron
Energy Technology Data Exchange (ETDEWEB)
Leitner, Daniela; McMahan, Margaret A.; Argento, David; Gimpel, Thomas; Guy, Aran; Morel, James; Siero, Christine; Thatcher, Ray; Lyneis, Claude M.
2002-09-03
Cyclotrons in combination with ECR ion sources provide the ability to accelerate ''cocktails'' of ions. A cocktail is a mixture of ions of near-identical mass-to-charge (m/q) ratio. The different ions cannot be separated by the injector mass-analyzing magnet and are tuned out of the ion source together. The cyclotron then is utilized as a mass analyzer by shifting the accelerating frequency. This concept was developed soon after the first ECR ion source became operational at the 88-Inch Cyclotron and has since become a powerful tool in the field of heavy ion radiation effects testing. Several different ''cocktails'' at various energies are available at the 88-Inch cyclotron for radiation effect testing, covering a broad range of linear energy transfer and penetration depth. Two standard heavy ion cocktails at 4.5 MeV/nucleon and 10 MeV/nucleon have been developed over the years containing ions from boron to bismuth. Recently, following requests for higher penetration depths, a 15MeV/nucleon heavy ion cocktail has been developed. Up to nine different metal and gaseous ion beams at low to very high charge states are tuned out of the ion source simultaneously and injected together into the cyclotron. It is therefore crucial to balance the ion source very carefully to provide sufficient intensities throughout the cocktail. The paper describes the set-up and tuning of the ion source for the various heavy ion cocktails.
Relativistic Electrons in Electric Discharges
DEFF Research Database (Denmark)
Cinar, Deniz
discharges as the source. The “Atmosphere-Space Interactions Monitor” (ASIM) for the International Space Station in 2016, led by DTU Space, and the French microsatellite TARANIS, also with launch in 2016, will identify with certainty the source of TGFs. In preparation for the missions, the Ph.D. project has...... developed a Monte Carlo module of a simulation code to model the formation of avalanches of electrons accelerated to relativistic energies, and the generation of bremsstrahlung through interactions with the neutral atmosphere. The code will be used in the analysis of data from the two space missions. We...... scattering. However, we only explored the properties of the complete number of photons reaching space, not the distribution at speci_c locations as in the case of a satellite. With this reservation we conclude that it is not possible to deduce much information from a satellite measurement of the photons...
Real vs. simulated relativistic jets
Gómez, J L; Agudo, I; Marscher, A P; Jorstad, S G; Aloy, M A
2005-01-01
Intensive VLBI monitoring programs of jets in AGN are showing the existence of intricate emission patterns, such as upstream motions or slow moving and quasi-stationary componentes trailing superluminal features. Relativistic hydrodynamic and emission simulations of jets are in very good agreement with these observations, proving as a powerful tool for the understanding of the physical processes taking place in the jets of AGN, microquasars and GRBs. These simulations show that the variability of the jet emission is the result of a complex combination of phase motions, viewing angle selection effects, and non-linear interactions between perturbations and the underlying jet and/or ambient medium. Both observations and simulations suggest that shock-in-jet models may be an overly simplistic idealization when interpreting the emission structure observed in actual jets.
Causal categories: relativistically interacting processes
Coecke, Bob
2011-01-01
A symmetric monoidal category naturally arises as the mathematical structure that organizes physical systems, processes, and composition thereof, both sequentially and in parallel. This structure admits a purely graphical calculus. This paper is concerned with the encoding of a fixed causal structure within a symmetric monoidal category: causal dependencies will correspond to topological connectedness in the graphical language. We show that correlations, either classical or quantum, force terminality of the tensor unit. We also show that well-definedness of the concept of a global state forces the monoidal product to be only partially defined, which in turn results in a relativistic covariance theorem. Except for these assumptions, at no stage do we assume anything more than purely compositional symmetric-monoidal categorical structure. We cast these two structural results in terms of a mathematical entity, which we call a `causal category'. We provide methods of constructing causal categories, and we study t...
Relativistic effects and quasipotential equations
Ramalho, G; Peña, M T
2002-01-01
We compare the scattering amplitude resulting from the several quasipotential equations for scalar particles. We consider the Blankenbecler-Sugar, Spectator, Thompson, Erkelenz-Holinde and Equal-Time equations, which were solved numerically without decomposition into partial waves. We analyze both negative-energy state components of the propagators and retardation effects. We found that the scattering solutions of the Spectator and the Equal-Time equations are very close to the nonrelativistic solution even at high energies. The overall relativistic effect increases with the energy. The width of the band for the relative uncertainty in the real part of the scattering $T$ matrix, due to different dynamical equations, is largest for backward-scattering angles where it can be as large as 40%.
Relativistic heavy-ion collisions
Bhalerao, Rajeev S
2014-01-01
The field of relativistic heavy-ion collisions is introduced to the high-energy physics students with no prior knowledge in this area. The emphasis is on the two most important observables, namely the azimuthal collective flow and jet quenching, and on the role fluid dynamics plays in the interpretation of the data. Other important observables described briefly are constituent quark number scaling, ratios of particle abundances, strangeness enhancement, and sequential melting of heavy quarkonia. Comparison is made of some of the basic heavy-ion results obtained at LHC with those obtained at RHIC. Initial findings at LHC which seem to be in apparent conflict with the accumulated RHIC data are highlighted.
General relativity and relativistic astrophysics
Mukhopadhyay, Banibrata
2016-01-01
Einstein established the theory of general relativity and the corresponding field equation in 1915 and its vacuum solutions were obtained by Schwarzschild and Kerr for, respectively, static and rotating black holes, in 1916 and 1963, respectively. They are, however, still playing an indispensable role, even after 100 years of their original discovery, to explain high energy astrophysical phenomena. Application of the solutions of Einstein's equation to resolve astrophysical phenomena has formed an important branch, namely relativistic astrophysics. I devote this article to enlightening some of the current astrophysical problems based on general relativity. However, there seem to be some issues with regard to explaining certain astrophysical phenomena based on Einstein's theory alone. I show that Einstein's theory and its modified form, both are necessary to explain modern astrophysical processes, in particular, those related to compact objects.
In search of relativistic time
Lachieze-Rey, Marc
2013-01-01
This paper explores the status of some notions which are usually associated to time, like datations, chronology, durations, causality, cosmic time and time functions in the Einsteinian relativistic theories. It shows how, even if some of these notions do exist in the theory or for some particular solution of it, they appear usually in mutual conflict: they cannot be synthesized coherently, and this is interpreted as the impossibility to construct a common entity which could be called time. This contrasts with the case in Newtonian physics where such a synthesis precisely constitutes Newtonian time. After an illustration by comparing the status of time in Einsteinian physics with that of the vertical direction in Newtonian physics, I will conclude that there is no pertinent notion of time in Einsteinian theories.
Playing relativistic billiards beyond graphene
Energy Technology Data Exchange (ETDEWEB)
Sadurni, E [Institut fuer Quantenphysik, Ulm Universitaet, Albert-Einstein Allee 11, 89081 Ulm (Germany); Seligman, T H [Centro Internacional de Ciencias A.C., Apartado Postal 6-101 C.P. 62131 Cuernavaca, Mor. (Mexico); Mortessagne, F, E-mail: esadurni@uni-ulm.d, E-mail: seligman@fis.unam.m, E-mail: fabrice.mortessagne@unice.f [Laboratoire de Physique de la Matiere Condensee, Universite de Nice-Sophia Antipolis, CNRS, UMR 6622 Parc Valrose, 06108 Nice cedex 2 (France)
2010-05-15
The possibility of using hexagonal structures in general, and graphene in particular, to emulate the Dirac equation is the topic under consideration here. We show that Dirac oscillators with or without rest mass can be emulated by distorting a tight-binding model on a hexagonal structure. In the quest to make a toy model for such relativistic equations, we first show that a hexagonal lattice of attractive potential wells would be a good candidate. Firstly, we consider the corresponding one-dimensional (1D) model giving rise to a 1D Dirac oscillator and then construct explicitly the deformations needed in the 2D case. Finally, we discuss how such a model can be implemented as an electromagnetic billiard using arrays of dielectric resonators between two conducting plates that ensure evanescent modes outside the resonators for transversal electric modes, and we describe a feasible experimental setup.
Playing relativistic billiards beyond graphene
Sadurní, E.; Seligman, T. H.; Mortessagne, F.
2010-05-01
The possibility of using hexagonal structures in general, and graphene in particular, to emulate the Dirac equation is the topic under consideration here. We show that Dirac oscillators with or without rest mass can be emulated by distorting a tight-binding model on a hexagonal structure. In the quest to make a toy model for such relativistic equations, we first show that a hexagonal lattice of attractive potential wells would be a good candidate. Firstly, we consider the corresponding one-dimensional (1D) model giving rise to a 1D Dirac oscillator and then construct explicitly the deformations needed in the 2D case. Finally, we discuss how such a model can be implemented as an electromagnetic billiard using arrays of dielectric resonators between two conducting plates that ensure evanescent modes outside the resonators for transversal electric modes, and we describe a feasible experimental setup.
Playing relativistic billiards beyond graphene
Sadurni, Emerson; Mortessagne, Fabrice
2010-01-01
The possibility of using hexagonal structures in general and graphene in particular to emulate the Dirac equation is the basis of our considerations. We show that Dirac oscillators with or without restmass can be emulated by distorting a tight binding model on a hexagonal structure. In a quest to make a toy model for such relativistic equations we first show that a hexagonal lattice of attractive potential wells would be a good candidate. First we consider the corresponding one-dimensional model giving rise to a one-dimensional Dirac oscillator, and then construct explicitly the deformations needed in the two-dimensional case. Finally we discuss, how such a model can be implemented as an electromagnetic billiard using arrays of dielectric resonators between two conducting plates that ensure evanescent modes outside the resonators for transversal electric modes, and describe an appropriate experimental setup.
Relativistic Kinetic Theory: An Introduction
Sarbach, Olivier
2013-01-01
We present a brief introduction to the relativistic kinetic theory of gases with emphasis on the underlying geometric and Hamiltonian structure of the theory. Our formalism starts with a discussion on the tangent bundle of a Lorentzian manifold of arbitrary dimension. Next, we introduce the Poincare one-form on this bundle, from which the symplectic form and a volume form are constructed. Then, we define an appropriate Hamiltonian on the bundle which, together with the symplectic form yields the Liouville vector field. The corresponding flow, when projected onto the base manifold, generates geodesic motion. Whenever the flow is restricted to energy surfaces corresponding to a negative value of the Hamiltonian, its projection describes a family of future-directed timelike geodesics. A collisionless gas is described by a distribution function on such an energy surface, satisfying the Liouville equation. Fibre integrals of the distribution function determine the particle current density and the stress-energy ten...
Thermodynamic Laws and Equipartition Theorem in Relativistic Brownian Motion
Koide, T.; Kodama, T.
2011-01-01
We extend the stochastic energetics to a relativistic system. The thermodynamic laws and equipartition theorem are discussed for a relativistic Brownian particle and the first and the second law of thermodynamics in this formalism are derived. The relation between the relativistic equipartition relation and the rate of heat transfer is discussed in the relativistic case together with the nature of the noise term.
Thermodynamic laws and equipartition theorem in relativistic Brownian motion.
Koide, T; Kodama, T
2011-06-01
We extend the stochastic energetics to a relativistic system. The thermodynamic laws and equipartition theorem are discussed for a relativistic Brownian particle and the first and the second law of thermodynamics in this formalism are derived. The relation between the relativistic equipartition relation and the rate of heat transfer is discussed in the relativistic case together with the nature of the noise term.
Surprising Sensitivities in Simulations of Radiative Convective Equilibrium
Drotos, Gabor; Becker, Tobias; Mauritsen, Thorsten; Stevens, Bjorn
2017-04-01
The climate and climate-sensitivity of a global model run in radiative equilibrium is explored. Results from simulations with ECHAM6.3 coupled to a slab ocean and run in a wide range of configurations are presented. Simulations both with and without a parameterised representation of deep convection are conducted for CO2 concentrations ranging from one eighth of present day values to thirty-two times the present day, and for variations in the solar constant of more than a factor of two. Very long simulations, in some case more than a thousand years, are performed to adequately sample the attractor of the different climate states of the model, and provide robust estimates of the system's climate sensitivity parameter. For the standard configuration of the model the climate sensitivity progressively decreases from very large values (6-7K) for the coldest climates to well below 1 K for the warmest climates. For very high CO2 levels (16 and 32 times the present value) fluctuations of globally averaged temperature as large as 10 K arise on decadal time-scales. These fluctuations manifest as quasi-period coolings, driven by large and persistent global scale decks of stratiform low clouds, so that for a period of several years global temperatures drop to levels below the lowest temperatures of the climate with present day values of CO2. The same configuration of the model has more modest sensitivities when the insolation is reduced, but runaway warming results for small (10%) increases. Simulations without parameterised convection have colder (by roughly 10K) climates and smaller (1K) sensitivities, allowing a stable climate with earth-like temperatures even for insolation much (50%) larger than the present day. Such values of insolation are possible because over a large range of the insolation the climate sensitivity parameter is very near zero. The surprising sensitivities of the system, and the limit-cycle like behaviour of the very CO2 rich climates, can be traced to
On the question of symmetries in non-relativistic diffeomorphism invariant theories
Banerjee, Rabin; Mukherjee, Pradip
2016-01-01
Nonrelativistic diffeomorphism invariance has recently emerged as a powerful tool for investigating various phenomena. The flat limit of such an invariance which should yield the Galilean invariance is, surprisingly, riddled with ambiguities and anomalies. We show that our approach, based on Galilean gauge theory, resolves these shortcomings. As a spin-off, we provide a systematic and unique way of interpreting nonrelativistic diffeomorphism invariance and Galilean invariance as appropriate nonrelativistic limits of relativistic invariances in curved and flat backgrounds, respectively. The complementary role of flat and nonrelativistic limits is highlighted.
Unitary representations of the Poincaré group and relativistic wave equations
Ohnuki, Yoshio
1976-01-01
This book is devoted to an extensive and systematic study on unitary representations of the Poincaré group. The Poincaré group plays an important role in understanding the relativistic picture of particles in quantum mechanics. Complete knowledge of every free particle states and their behaviour can be obtained once all the unitary irreducible representations of the Poincaré group are found. It is a surprising fact that a simple framework such as the Poincaré group, when unified with quantum theory, fixes our possible picture of particles severely and without exception. In this connection, the
Holographic Aspects of a Relativistic Nonconformal Theory
Directory of Open Access Journals (Sweden)
Chanyong Park
2013-01-01
Full Text Available We study a general D-dimensional Schwarzschild-type black brane solution of the Einstein-dilaton theory and derive, by using the holographic renormalization, its thermodynamics consistent with the geometric results. Using the membrane paradigm, we calculate the several hydrodynamic transport coefficients and compare them with the results obtained by the Kubo formula, which shows the self-consistency of the gauge/gravity duality in the relativistic nonconformal theory. In order to understand more about the relativistic non-conformal theory, we further investigate the binding energy, drag force, and holographic entanglement entropy of the relativistic non-conformal theory.
Relativistic MHD with Adaptive Mesh Refinement
Anderson, M; Liebling, S L; Neilsen, D; Anderson, Matthew; Hirschmann, Eric; Liebling, Steven L.; Neilsen, David
2006-01-01
We solve the relativistic magnetohydrodynamics (MHD) equations using a finite difference Convex ENO method (CENO) in 3+1 dimensions within a distributed parallel adaptive mesh refinement (AMR) infrastructure. In flat space we examine a Balsara blast wave problem along with a spherical blast wave and a relativistic rotor test both with unigrid and AMR simulations. The AMR simulations substantially improve performance while reproducing the resolution equivalent unigrid simulation results. We also investigate the impact of hyperbolic divergence cleaning for the spherical blast wave and relativistic rotor. We include unigrid and mesh refinement parallel performance measurements for the spherical blast wave.
Relativistic Electron Experiment for the Undergraduate Laboratory
Marvel, Robert E
2011-01-01
We have developed an undergraduate laboratory experiment to make independent measurements of the momentum and kinetic energy of relativistic electrons from a \\beta -source. The momentum measurements are made with a magnetic spectrometer and a silicon surface-barrier detector is used to measure the kinetic energy. A plot of the kinetic energy as a function of momentum compared to the classical and relativistic predictions clearly shows the relativistic nature of the electrons. Accurate values for the rest mass of the electron and the speed of light are also extracted from the data.
DYNAMICS OF RELATIVISTIC FLUID FOR COMPRESSIBLE GAS
Institute of Scientific and Technical Information of China (English)
无
2011-01-01
In this paper the relativistic fluid dynamics for compressible gas is studied.We show that the strict convexity of the negative thermodynamical entropy preserves invariant under the Lorentz transformation if and only if the local speed of sound in this gas is strictly less than that of light in the vacuum.A symmetric form for the equations of relativistic hydrodynamics is presented,and thus the local classical solutions to these equations can be deduced.At last,the non-relativistic limits of these local cla...
Pireaux, S
2008-01-01
The Relativistic Motion Integrator (RMI) consists in integrating numerically the EXACT relativistic equations of motion, with respect to the appropriate gravitational metric, instead of Newtonian equations plus relativistic corrections. The aim of the present paper is to validate the method, and to illustrate how RMI can be used for space missions to produce relativistic ephemerides of satellites. Indeed, nowadays, relativistic effects have to be taken into account, and comparing a RMI ephemeris with a classical keplerian one helps to quantify such effects. LISA is a relevant example to use RMI. This mission is an interferometer formed by three spacecraft which aims at the detection of gravitational waves. Precise ephemerides of LISA spacecraft are needed not only for the sake of the orbitography but also to compute the photon flight time in laser links between spacecraft, required in LISA data pre-processing in order to reach the gravitational wave detection level. Relativistic effects in LISA orbitography n...
Stars Form Surprisingly Close to Milky Way's Black Hole
2005-10-01
The supermassive black hole at the center of the Milky Way has surprisingly helped spawn a new generation of stars, according to observations from NASA's Chandra X-ray Observatory. This novel mode of star formation may solve several mysteries about the supermassive black holes that reside at the centers of nearly all galaxies. "Massive black holes are usually known for violence and destruction," said Sergei Nayakshin of the University of Leicester, United Kingdom, and coauthor of a paper on this research in an upcoming issue of the Monthly Notices of the Royal Astronomical Society. "So it's remarkable that this black hole helped create new stars, not just destroy them." Black holes have earned their fearsome reputation because any material -- including stars -- that falls within the so-called event horizon is never seen again. However, these new results indicate that the immense disks of gas known to orbit many black holes at a "safe" distance from the event horizon can help nurture the formation of new stars. Animation of Stars Forming Around Black Hole Animation of Stars Forming Around Black Hole This conclusion came from new clues that could only be revealed in X-rays. Until the latest Chandra results, astronomers have disagreed about the origin of a mysterious group of massive stars discovered by infrared astronomers to be orbiting less than a light year from the Milky Way's central black hole, a.k.a. Sagittarius A*, or Sgr A*. At such close distances to Sgr A*, the standard model for star formation predicts that gas clouds from which stars form should have been ripped apart by tidal forces from the black hole. Two models to explain this puzzle have been proposed. In the disk model, the gravity of a dense disk of gas around Sgr A* offsets the tidal forces and allows stars to form; in the migration model, the stars formed in a star cluster far away from the black hole and migrated in to form the ring of massive stars. The migration scenario predicts about a
Explaining the dynamics of the ultra-relativistic third Van Allen radiation belt
Mann, I. R.; Ozeke, L. G.; Murphy, K. R.; Claudepierre, S. G.; Turner, D. L.; Baker, D. N.; Rae, I. J.; Kale, A.; Milling, D. K.; Boyd, A. J.; Spence, H. E.; Reeves, G. D.; Singer, H. J.; Dimitrakoudis, S.; Daglis, I. A.; Honary, F.
2016-10-01
Since the discovery of the Van Allen radiation belts over 50 years ago, an explanation for their complete dynamics has remained elusive. Especially challenging is understanding the recently discovered ultra-relativistic third electron radiation belt. Current theory asserts that loss in the heart of the outer belt, essential to the formation of the third belt, must be controlled by high-frequency plasma wave-particle scattering into the atmosphere, via whistler mode chorus, plasmaspheric hiss, or electromagnetic ion cyclotron waves. However, this has failed to accurately reproduce the third belt. Using a data-driven, time-dependent specification of ultra-low-frequency (ULF) waves we show for the first time how the third radiation belt is established as a simple, elegant consequence of storm-time extremely fast outward ULF wave transport. High-frequency wave-particle scattering loss into the atmosphere is not needed in this case. When rapid ULF wave transport coupled to a dynamic boundary is accurately specified, the sensitive dynamics controlling the enigmatic ultra-relativistic third radiation belt are naturally explained.
Simulations and Theory of Ion Injection at Non-relativistic Collisionless Shocks
Caprioli, Damiano; Pop, Ana-Roxana; Spitkovsky, Anatoly
2015-01-01
We use kinetic hybrid simulations (kinetic ions-fluid electrons) to characterize the fraction of ions that are accelerated to non-thermal energies at non-relativistic collisionless shocks. We investigate the properties of the shock discontinuity and show that shocks propagating almost along the background magnetic field (quasi-parallel shocks) reform quasi-periodically on ion cyclotron scales. Ions that impinge on the shock when the discontinuity is the steepest are specularly reflected. This is a necessary condition for being injected, but it is not sufficient. Also, by following the trajectories of reflected ions, we calculate the minimum energy needed for injection into diffusive shock acceleration, as a function of the shock inclination. We construct a minimal model that accounts for the ion reflection from quasi-periodic shock barrier, for the fraction of injected ions, and for the ion spectrum throughout the transition from thermal to non-thermal energies. This model captures the physics relevant for ion injection at non-relativistic astrophysical shocks with arbitrary strengths and magnetic inclinations, and represents a crucial ingredient for understanding the diffusive shock acceleration of cosmic rays.
Spitkovsky, A; Spitkovsky, Anatoly; Arons, Jonathan
2004-01-01
We describe results from time-dependent numerical modeling of the collisionless reverse shock terminating the pulsar wind in the Crab Nebula. We treat the upstream relativistic wind as composed of ions and electron-positron plasma embedded in a toroidal magnetic field, flowing radially outward from the pulsar in a sector around the rotational equator. The relativistic cyclotron instability of the ion gyrational orbit downstream of the leading shock in the electron-positron pairs launches outward propagating magnetosonic waves. Because of the fresh supply of ions crossing the shock, this time-dependent process achieves a limit-cycle, in which the waves are launched with periodicity on the order of the ion Larmor time. Compressions in the magnetic field and pair density associated with these waves, as well as their propagation speed, semi-quantitatively reproduce the behavior of the wisp and ring features described in recent observations obtained using the Hubble Space Telescope and the Chandra X-Ray Observator...
Confirmation of EMIC wave-driven relativistic electron precipitation
Hendry, Aaron T.; Rodger, Craig J.; Clilverd, Mark A.; Engebretson, Mark J.; Mann, Ian R.; Lessard, Marc R.; Raita, Tero; Milling, David K.
2016-06-01
Electromagnetic ion cyclotron (EMIC) waves are believed to be an important source of pitch angle scattering driven relativistic electron loss from the radiation belts. To date, investigations of this precipitation have been largely theoretical in nature, limited to calculations of precipitation characteristics based on wave observations and small-scale studies. Large-scale investigation of EMIC wave-driven electron precipitation has been hindered by a lack of combined wave and precipitation measurements. Analysis of electron flux data from the POES (Polar Orbiting Environmental Satellites) spacecraft has been suggested as a means of investigating EMIC wave-driven electron precipitation characteristics, using a precipitation signature particular to EMIC waves. Until now the lack of supporting wave measurements for these POES-detected precipitation events has resulted in uncertainty regarding the driver of the precipitation. In this paper we complete a statistical study comparing POES precipitation measurements with wave data from several ground-based search coil magnetometers; we further present a case study examining the global nature of this precipitation. We show that a significant proportion of the precipitation events correspond with EMIC wave detections on the ground; for precipitation events that occur directly over the magnetometers, this detection rate can be as high as 90%. Our results demonstrate that the precipitation region is often stationary in magnetic local time, narrow in L, and close to the expected plasmapause position. Predominantly, the precipitation is associated with helium band rising tone Pc1 waves on the ground. The success of this study proves the viability of POES precipitation data for investigating EMIC wave-driven electron precipitation.
Relativistic elastic differential cross sections for equal mass nuclei
Directory of Open Access Journals (Sweden)
C.M. Werneth
2015-10-01
Full Text Available The effects of relativistic kinematics are studied for nuclear collisions of equal mass nuclei. It is found that the relativistic and non-relativistic elastic scattering amplitudes are nearly indistinguishable, and, hence, the relativistic and non-relativistic differential cross sections become indistinguishable. These results are explained by analyzing the Lippmann–Schwinger equation with the first order optical potential that was employed in the calculation.
Relativistic elastic differential cross sections for equal mass nuclei
Energy Technology Data Exchange (ETDEWEB)
Werneth, C.M., E-mail: charles.m.werneth@nasa.gov [NASA Langley Research Center, 2 West Reid Street, Hampton, VA 23681 (United States); Maung, K.M.; Ford, W.P. [The University of Southern Mississippi, 118 College Drive, Box 5046, Hattiesburg, MS 39406 (United States)
2015-10-07
The effects of relativistic kinematics are studied for nuclear collisions of equal mass nuclei. It is found that the relativistic and non-relativistic elastic scattering amplitudes are nearly indistinguishable, and, hence, the relativistic and non-relativistic differential cross sections become indistinguishable. These results are explained by analyzing the Lippmann–Schwinger equation with the first order optical potential that was employed in the calculation.
Energy Technology Data Exchange (ETDEWEB)
Artru, X. [Inst. de Physique Nucleaire, Lyon-1 Univ., 69 - Villeurbanne (France); Collaboration: IPN-Lyon, IRMM (Gell), LURE (Orsay); Collaboration: IPN-Lyon, LAL and IEF (Orsay), HIP (Helsinki), INFN (Frascati, Milan)
1998-12-31
We have studied different effects related to electromagnetic interaction of relativistic electrons in matter and investigated their use in beam profile measurements. (authors) 4 refs. Short communication
Carbon Dioxide: Surprising Effects on Decision Making and Neurocognitive Performance
James, John T.
2013-01-01
The occupants of modern submarines and the International Space Station (ISS) have much in common as far as their air quality is concerned. Air is polluted by materials offgassing, use of utility compounds, leaks of systems chemicals, and anthropogenic sources. The primary anthropogenic compound of concern to submariners and astronauts has been carbon dioxide (CO2). NASA and the US Navy rely on the National Research Council Committee on Toxicology (NRC-COT) to help formulate exposure levels to CO2 that are thought to be safe for exposures of 3-6 months. NASA calls its limits Spacecraft Maximum Allowable Concentrations (SMACs). Years of experience aboard the ISS and a recent publication on deficits in decision making in ground-based subjects exposed briefly to 0.25% CO2 suggest that exposure levels that have been presumed acceptable to preserve health and performance need to be reevaluated. The current CO2 exposure limits for 3-6 months set by NASA and the UK Navy are 0.7%, and the limit for US submariners is 0.5%, although the NRC-COT recommended a 90-day level of 0.8% as safe a few years ago. NASA has set a 1000-day SMAC at 0.5% for exploration-class missions. Anecdotal experience with ISS operations approaching the current 180-day SMAC of 0.7% suggest that this limit is too high. Temporarily, NASA has limited exposures to 0.5% until further peer-reviewed data become available. In the meantime, a study published last year in the journal Environmental Health Perspectives (Satish U, et al. 2012) demonstrated that complexdecision- making performance is somewhat affected at 0.1% CO2 and becomes "dysfunctional" for at least half of the 9 indices of performance at concentrations approaching 0.25% CO2. The investigators used the Strategic Management Simulation (SMS) method of testing for decisionmaking ability, and the results were so surprising to the investigators that they declared that their findings need to be independently confirmed. NASA has responded to the
Are seismic hazard assessment errors and earthquake surprises unavoidable?
Kossobokov, Vladimir
2013-04-01
Why earthquake occurrences bring us so many surprises? The answer seems evident if we review the relationships that are commonly used to assess seismic hazard. The time-span of physically reliable Seismic History is yet a small portion of a rupture recurrence cycle at an earthquake-prone site, which makes premature any kind of reliable probabilistic statements about narrowly localized seismic hazard. Moreover, seismic evidences accumulated to-date demonstrate clearly that most of the empirical relations commonly accepted in the early history of instrumental seismology can be proved erroneous when testing statistical significance is applied. Seismic events, including mega-earthquakes, cluster displaying behaviors that are far from independent or periodic. Their distribution in space is possibly fractal, definitely, far from uniform even in a single segment of a fault zone. Such a situation contradicts generally accepted assumptions used for analytically tractable or computer simulations and complicates design of reliable methodologies for realistic earthquake hazard assessment, as well as search and definition of precursory behaviors to be used for forecast/prediction purposes. As a result, the conclusions drawn from such simulations and analyses can MISLEAD TO SCIENTIFICALLY GROUNDLESS APPLICATION, which is unwise and extremely dangerous in assessing expected societal risks and losses. For example, a systematic comparison of the GSHAP peak ground acceleration estimates with those related to actual strong earthquakes, unfortunately, discloses gross inadequacy of this "probabilistic" product, which appears UNACCEPTABLE FOR ANY KIND OF RESPONSIBLE SEISMIC RISK EVALUATION AND KNOWLEDGEABLE DISASTER PREVENTION. The self-evident shortcomings and failures of GSHAP appeals to all earthquake scientists and engineers for an urgent revision of the global seismic hazard maps from the first principles including background methodologies involved, such that there becomes: (a) a
Clumps in large scale relativistic jets
Tavecchio, F; Celotti, A
2003-01-01
The relatively intense X-ray emission from large scale (tens to hundreds kpc) jets discovered with Chandra likely implies that jets (at least in powerful quasars) are still relativistic at that distances from the active nucleus. In this case the emission is due to Compton scattering off seed photons provided by the Cosmic Microwave Background, and this on one hand permits to have magnetic fields close to equipartition with the emitting particles, and on the other hand minimizes the requirements about the total power carried by the jet. The emission comes from compact (kpc scale) knots, and we here investigate what we can predict about the possible emission between the bright knots. This is motivated by the fact that bulk relativistic motion makes Compton scattering off the CMB photons efficient even when electrons are cold or mildly relativistic in the comoving frame. This implies relatively long cooling times, dominated by adiabatic losses. Therefore the relativistically moving plasma can emit, by Compton sc...
General relativistic corrections and non-Gaussianity
Villa, Eleonora; Matarrese, Sabino
2014-01-01
General relativistic cosmology cannot be reduced to linear relativistic perturbations superposed on an isotropic and homogeneous (Friedmann-Robertson-Walker) background, even though such a simple scheme has been successfully applied to analyse a large variety of phenomena (such as Cosmic Microwave Background primary anisotropies, matter clustering on large scales, weak gravitational lensing, etc.). The general idea of going beyond this simple paradigm is what characterises most of the efforts made in recent years: the study of second and higher-order cosmological perturbations including all general relativistic contributions -- also in connection with primordial non-Gaussianities -- the idea of defining large-scale structure observables directly from a general relativistic perspective, the various attempts to go beyond the Newtonian approximation in the study of non-linear gravitational dynamics, by using e.g., Post-Newtonian treatments, are all examples of this general trend. Here we summarise some of these ...
Relativistic Thermodynamics: A Modern 4-Vector Approach
Directory of Open Access Journals (Sweden)
J. Güémez
2011-01-01
Full Text Available Using the Minkowski relativistic 4-vector formalism, based on Einstein's equation, and the relativistic thermodynamics asynchronous formulation (Grøn (1973, the isothermal compression of an ideal gas is analyzed, considering an electromagnetic origin for forces applied to it. This treatment is similar to the description previously developed by Van Kampen (van Kampen (1969 and Hamity (Hamity (1969. In this relativistic framework Mechanics and Thermodynamics merge in the first law of relativistic thermodynamics expressed, using 4-vector notation, such as ΔUμ = Wμ + Qμ, in Lorentz covariant formulation, which, with the covariant formalism for electromagnetic forces, constitutes a complete Lorentz covariant formulation for classical physics.
Relativistic effect of spin and pseudospin symmetries
Chen, Shou-Wan
2012-01-01
Dirac Hamiltonian is scaled in the atomic units $\\hbar =m=1$, which allows us to take the non-relativistic limit by setting the Compton wavelength $% \\lambda \\rightarrow 0 $. The evolutions of the spin and pseudospin symmetries towards the non-relativistic limit are investigated by solving the Dirac equation with the parameter $\\lambda$. With $\\lambda$ transformation from the original Compton wavelength to 0, the spin splittings decrease monotonously in all spin doublets, and the pseudospin splittings increase in several pseudospin doublets, no change, or even reduce in several other pseudospin doublets. The various energy splitting behaviors of both the spin and pseudospin doublets with $\\lambda$ are well explained by the perturbation calculations of Dirac Hamiltonian in the present units. It indicates that the origin of spin symmetry is entirely due to the relativistic effect, while the origin of pseudospin symmetry cannot be uniquely attributed to the relativistic effect.
Relativistic calculations of coalescing binary neutron stars
Indian Academy of Sciences (India)
Joshua Faber; Phillippe Grandclément; Frederic Rasio
2004-10-01
We have designed and tested a new relativistic Lagrangian hydrodynamics code, which treats gravity in the conformally flat approximation to general relativity. We have tested the resulting code extensively, finding that it performs well for calculations of equilibrium single-star models, collapsing relativistic dust clouds, and quasi-circular orbits of equilibrium solutions. By adding a radiation reaction treatment, we compute the full evolution of a coalescing binary neutron star system. We find that the amount of mass ejected from the system, much less than a per cent, is greatly reduced by the inclusion of relativistic gravitation. The gravity wave energy spectrum shows a clear divergence away from the Newtonian point-mass form, consistent with the form derived from relativistic quasi-equilibrium fluid sequences.
Non-Newtonian Properties of Relativistic Fluids
Koide, Tomoi
2010-01-01
We show that relativistic fluids behave as non-Newtonian fluids. First, we discuss the problem of acausal propagation in the diffusion equation and introduce the modified Maxwell-Cattaneo-Vernotte (MCV) equation. By using the modified MCV equation, we obtain the causal dissipative relativistic (CDR) fluid dynamics, where unphysical propagation with infinite velocity does not exist. We further show that the problems of the violation of causality and instability are intimately related, and the relativistic Navier-Stokes equation is inadequate as the theory of relativistic fluids. Finally, the new microscopic formula to calculate the transport coefficients of the CDR fluid dynamics is discussed. The result of the microscopic formula is consistent with that of the Boltzmann equation, i.e., Grad's moment method.
Energy spectra in relativistic electron precipitation events.
Rosenberg, T. J.; Lanzerotti, L. J.; Bailey, D. K.; Pierson, J. D.
1972-01-01
Two events in August 1967, categorized as relativistic electron precipitation (REP) events by their effect on VHF transmissions propagated via the forward-scatter mode, have been examined with regard to the energy spectra of trapped and precipitated electrons. These two substorm-associated events August 11 and August 25 differ with respect to the relativistic, trapped electron population at synchronous altitude; in the August 25 event there was a nonadiabatic enhancement of relativistic (greater than 400 keV) electrons, while in the August 11 event no relativistic electrons were produced. In both events electron spectra deduced from bremsstrahlung measurements (made on a field line close to that of the satellite) had approximately the same e-folding energies as the trapped electron enhancements. However, the spectrum of electrons in the August 25 event was significantly harder than the spectrum in the event of August 11.
Relativistic Effects at the Freshman Level.
Banna, M. Salim
1985-01-01
Summarizes the content of a lecture in which relativistic effects in chemistry are introduced through a calculation that illustrates these effects on the s and p electrons and that can be verified by photoelectron spectroscopy data. (JN)
Star Products for Relativistic Quantum Mechanics
Henselder, P.
2007-01-01
The star product formalism has proved to be an alternative formulation for nonrelativistic quantum mechanics. We want introduce here a covariant star product in order to extend the star product formalism to relativistic quantum mechanics in the proper time formulation.
Relabeling symmetry in relativistic fluids and plasmas
Kawazura, Yohei; Fukumoto, Yasuhide
2014-01-01
The conservation of the recently formulated relativistic canonical helicity [Yoshida Z, Kawazura Y, and Yokoyama T 2014 J. Math. Phys. 55 043101] is derived from Noether's theorem by constructing an action principle on the relativistic Lagrangian coordinates (we obtain general cross helicities that include the helicity of the canonical vorticity). The conservation law is, then, explained by the relabeling symmetry pertinent to the Lagrangian label of fluid elements. Upon Eulerianizing the Noether current, the purely spatial volume integral on the Lagrangian coordinates is mapped to a space-time mixed three-dimensional integral on the four-dimensional Eulerian coordinates. The relativistic conservation law in the Eulerian coordinates is no longer represented by any divergence-free current; hence, it is not adequate to regard the relativistic helicity (represented by the Eulerian variables) as a Noether charge, and this stands the reason why the "conventional helicity" is no longer a constant of motion. We have...
Relativistic diffusion equation from stochastic quantization
Kazinski, P O
2007-01-01
The new scheme of stochastic quantization is proposed. This quantization procedure is equivalent to the deformation of an algebra of observables in the manner of deformation quantization with an imaginary deformation parameter (the Planck constant). We apply this method to the models of nonrelativistic and relativistic particles interacting with an electromagnetic field. In the first case we establish the equivalence of such a quantization to the Fokker-Planck equation with a special force. The application of the proposed quantization procedure to the model of a relativistic particle results in a relativistic generalization of the Fokker-Planck equation in the coordinate space, which in the absence of the electromagnetic field reduces to the relativistic diffusion (heat) equation. The stationary probability distribution functions for a stochastically quantized particle diffusing under a barrier and a particle in the potential of a harmonic oscillator are derived.
Relativistic Langevin equation for runaway electrons
Mier, J. A.; Martin-Solis, J. R.; Sanchez, R.
2016-10-01
The Langevin approach to the kinetics of a collisional plasma is developed for relativistic electrons such as runaway electrons in tokamak plasmas. In this work, we consider Coulomb collisions between very fast, relativistic electrons and a relatively cool, thermal background plasma. The model is developed using the stochastic equivalence of the Fokker-Planck and Langevin equations. The resulting Langevin model equation for relativistic electrons is an stochastic differential equation, amenable to numerical simulations by means of Monte-Carlo type codes. Results of the simulations will be presented and compared with the non-relativistic Langevin equation for RE electrons used in the past. Supported by MINECO (Spain), Projects ENE2012-31753, ENE2015-66444-R.
Solutions of relativistic radial quasipotential equations
Energy Technology Data Exchange (ETDEWEB)
Minh, V.X.; Kadyshevskii, V.G.; Zhidkov, E.P.
1985-11-01
A systematic approach to the investigation of relativistic radial quasipotential equations is developed. The quasipotential equations can be interpreted either as linear equations in finite differences of fourth and second orders, respectively, or as differential equations of infinite order.
Spin, localization and uncertainty of relativistic fermions
Céleri, Lucas C; Terno, Daniel R
2016-01-01
We describe relations between several relativistic spin observables and derive a Lorentz-invariant characteristic of a reduced spin density matrix. A relativistic position operator that satisfies all the properties of its non-relativistic analogue does not exist. Instead we propose two causality-preserving positive operator-valued measures (POVM) that are based on projections onto one-particle and antiparticle spaces, and on the normalized energy density. They predict identical expectation values for position. The variances differ by less than a quarter of the squared de Broglie wavelength and coincide in the non-relativistic limit. Since the resulting statistical moment operators are not canonical conjugates of momentum, the Heisenberg uncertainty relations need not hold. Indeed, the energy density POVM leads to a lower uncertainty. We reformulate the standard equations of the spin dynamics by explicitly considering the charge-independent acceleration, allowing a consistent treatment of backreaction and incl...
Relativistic Model for two-band Superconductivity
Ohsaku, Tadafumi
2003-01-01
To understand the superconductivity in MgB2, several two-band models of superconductivity were proposed. In this paper, by using the relativistic fermion model, we clearize the effect of the lower band in the superconductivity.
Westerhof, E.; Austin, M. E.; Kubo, S.; Lin-Liu, Y. R.; Plaum, B.
2013-01-01
An overview is given of the papers presented at the 17th Joint Workshop on Electron Cyclotron Emission (ECE) and Electron Cyclotron Resonance Heating (ECRH). The meeting covered all aspects of the research field ranging from theory to enabling technologies. From the workshop, advanced control by ele
On Lorentz invariants in relativistic magnetic reconnection
Yang, Shu-Di; Wang, Xiao-Gang
2016-08-01
Lorentz invariants whose nonrelativistic correspondences play important roles in magnetic reconnection are discussed in this paper. Particularly, the relativistic invariant of the magnetic reconnection rate is defined and investigated in a covariant two-fluid model. Certain Lorentz covariant representations for energy conversion and magnetic structures in reconnection processes are also investigated. Furthermore, relativistic measures for topological features of reconnection sites, particularly magnetic nulls and separatrices, are analyzed.
On the convexity of Relativistic Hydrodynamics
Ibáñez, José María; Martí, José María; Miralles, Juan Antonio; 10.1088/0264-9381/30/5/057002
2013-01-01
The relativistic hydrodynamic system of equations for a perfect fluid obeying a causal equation of state is hyperbolic (Anile 1989 {\\it Relativistic Fluids and Magneto-Fluids} (Cambridge: Cambridge University Press)). In this report, we derive the conditions for this system to be convex in terms of the fundamental derivative of the equation of state (Menikoff and Plohr 1989 {\\it Rev. Mod. Phys.} {\\bf 61} 75). The classical limit is recovered.
Benedicks effect in a relativistic simple fluid
Garcia-Perciante, A L; Garcia-Colin, L S
2013-01-01
According to standard thermophysical theories, cross effects are mostly present in multicomponent systems. In this paper we show that for relativistic fluids an electric field generates a heat flux even in the single component case. In the non-relativistic limit the effect vanishes and Fourier's law is recovered. This result is novel and may have applications in the transport properties of very hot plasmas.
New Developments in Relativistic Viscous Hydrodynamics
Romatschke, Paul
2009-01-01
Starting with a brief introduction into the basics of relativistic fluid dynamics, I discuss our current knowledge of a relativistic theory of fluid dynamics in the presence of (mostly shear) viscosity. Derivations based on the generalized second law of thermodynamics, kinetic theory, and a complete second-order gradient expansion are reviewed. The resulting fluid dynamic equations are shown to be consistent for all these derivations, when properly accounting for the respective region of appl...
Limits and Signatures of Relativistic Spaceflight
Yurtsever, Ulvi
2015-01-01
While special relativity imposes an absolute speed limit at the speed of light, our Universe is not empty Minkowski spacetime. The constituents that fill the interstellar/intergalactic vacuum, including the cosmic microwave background photons, impose a lower speed limit on any object travelling at relativistic velocities. Scattering of cosmic microwave phtotons from an ultra-relativistic object may create radiation with a characteristic signature allowing the detection of such objects at large distances.
Chiral quark model with relativistic kinematics
Garcilazo, H
2003-01-01
The non-strange baryon spectrum is studied within a three-body model that incorporates relativistic kinematics. We found that the combined effect of relativistic kinematics together with the pion exchange between quarks is able to reverse the order of the first positive- and negative-parity nucleon excited states as observed experimentally. Including the chiral partner of the pion (the $\\sigma$ meson) leads to an overall good description of the spectrum.
Relativistic diffusive motion in random electromagnetic fields
Energy Technology Data Exchange (ETDEWEB)
Haba, Z, E-mail: zhab@ift.uni.wroc.pl [Institute of Theoretical Physics, University of Wroclaw, 50-204 Wroclaw, Plac Maxa Borna 9 (Poland)
2011-08-19
We show that the relativistic dynamics in a Gaussian random electromagnetic field can be approximated by the relativistic diffusion of Schay and Dudley. Lorentz invariant dynamics in the proper time leads to the diffusion in the proper time. The dynamics in the laboratory time gives the diffusive transport equation corresponding to the Juettner equilibrium at the inverse temperature {beta}{sup -1} = mc{sup 2}. The diffusion constant is expressed by the field strength correlation function (Kubo's formula).
Evidence for acceleration of outer zone electrons to relativistic energies by whistler mode chorus
Directory of Open Access Journals (Sweden)
N. P. Meredith
Full Text Available We use plasma wave and electron data from the Combined Release and Radiation Effects Satellite (CRRES to investigate the viability of a local stochastic electron acceleration mechanism to relativistic energies driven by gyroresonant interactions with whistler mode chorus. In particular, we examine the temporal evolution of the spectral response of the electrons and the waves during the 9 October 1990 geomagnetic storm. The observed hardening of the electron energy spectra over about 3 days in the recovery phase is coincident with prolonged substorm activity, as monitored by the AE index and enhanced levels of whistler mode chorus waves. The observed spectral hardening is observed to take place over a range of energies appropriate to the resonant energies associated with Doppler-shifted cyclotron resonance, as supported by the construction of realistic resonance curves and resonant diffusion surfaces. Furthermore, we show that the observed spectral hardening is not consistent with energy-independent radial diffusion models. These results provide strong circumstantial evidence for a local stochastic acceleration mechanism, involving the energisation of a seed population of electrons with energies of the order of a few hundred keV to relativistic energies, driven by wave-particle interactions involving whistler mode chorus. The results suggest that this mechanism contributes to the reformation of the relativistic outer zone population during geomagnetic storms, and is most effective when the recovery phase is characterised by prolonged substorm activity. An additional significant result of this paper is that we demonstrate that the lower energy part of the storm-time electron distribution is in steady-state balance, in accordance with the Kennel and Petschek (1966 theory of limited stably-trapped particle fluxes.
Key words. Magnetospheric physics (storms and substorms, energetic particles, trapped – Space plasma physics (wave
Examination of the Plasma located in PSI Ring Cyclotron
Pogue, Nathaniel; Schneider, Markus; Stingelin, Lukas
2016-01-01
A plasma has been observed inside the vacuum chamber of the PSI Ring Cyclotron. This ionized gas cloud maybe a substantial contributor to several interior components having reduced lifetimes. The plasma's generation has been directly linked to the voltage that is applied to the Flat Top Cavity through visual confirmation using CCD cameras. A spectrometer was used to correlate the plasma's intensity and ignition to the Flat Top Cavity voltage as well as to determine the composition of the plasma. This paper reports on the analysis of the plasma using spectroscopy. The spectrometer data was analyzed to determine the composition of the plasma and that the plasma intensity (luminosity) directly corresponds to the Flat Top voltage. The results showed that the plasma was comprised of elements consistent with the cyclotrons vacuum interior
Vortex dynamics and shear layer instability in high intensity cyclotrons
Cerfon, Antoine J
2016-01-01
We show that the space charge dynamics of high intensity beams in the plane perpendicular to the magnetic field in cyclotrons is described by the two-dimensional Euler equations for an incompressible fluid. This analogy with fluid dynamics gives a unified and intuitive framework to explain the beam spiraling and beam break up behavior observed in experiments and in simulations. In particular, we demonstrate that beam break up is the result of a classical instability occurring in fluids subject to a sheared flow. We give scaling laws for the instability and predict the nonlinear evolution of beams subject to it. Our work suggests that cyclotrons may be uniquely suited for the experimental study of shear layers and vortex distributions that are not achievable in Penning-Malmberg traps.
Ernest Orlando Lawrence (1901-1958), Cyclotron and Medicine
Energy Technology Data Exchange (ETDEWEB)
Chu, William T.
2005-09-01
On August 8, 2001, Lawrence Berkeley National Laboratory celebrated the centennial of the birth of its founder (and namesake), Ernest Orlando Lawrence. For the occasion, many speeches were given and old speeches were remembered. We recall the words of the late Luis Alvarez, a Nobel Laureate and one of the Lawrence's closest colleagues: ''Lawrence will always be remembered as the inventor of the cyclotron, but more importantly, he should be remembered as the inventor of the modern way of doing science''. J. L. Heilbron and R. W. Seidel, in the introduction of their book, ''Lawrence and His Laboratory'' stated, ''The motives and mechanisms that shaped the growth of the Laboratory helped to force deep changes in the scientific estate and in the wider society. In the entrepreneurship of its founder, Ernest Orlando Lawrence, these motives, mechanisms, and changes came together in a tight focus. He mobilized great and small philanthropists, state and local governments, corporations, and plutocrats, volunteers and virtuosos. The work they supported, from astrophysics and atomic bombs, from radiochemistry to nuclear medicine, shaped the way we observe, control, and manipulate our environment.'' Indeed, all over the civilized world, the ways we do science changed forever after Lawrence built his famed Radiation Laboratory. In this editorial, we epitomize his legacy of changing the way we do medicine, thereby affecting the health and well being of all humanity. This year marks the 75th anniversary of the invention of the cyclotron by Ernest Orlando Lawrence at the University of California at Berkeley. Lawrence conceived the idea of the cyclotron early in 1929 after reading an article by Rolf Wideroe on high-energy accelerators. In the spring of 1930 one of his students, Nels Edlefsen, constructed two crude models of a cyclotron. Later in the fall of the same year, another student, M. Stanley Livingston
RF cavity design for KIRAMS-430 superconducting cyclotron
Energy Technology Data Exchange (ETDEWEB)
Jung, In Su, E-mail: jis@kirams.re.kr [Korea Institute of Radiological & Medical Sciences (KIRMAS), 75 Nowon-Gil, Nowon-Gu, Seoul 139-706 (Korea, Republic of); Hong, Bong Hwan; Kang, Joonsun; Kim, Hyun Wook; Kim, Chang Hyeuk [Korea Institute of Radiological & Medical Sciences (KIRMAS), 75 Nowon-Gil, Nowon-Gu, Seoul 139-706 (Korea, Republic of); Kwon, Key Ho [School of Information and Communication Engineering, Natural Sciences Campus, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of)
2015-03-21
The Korea Heavy Ion Medical Accelerator (KHIMA) has developed a superconducting cyclotron for the carbon therapy, which is called KIRAMS-430. The cyclotron is designed to accelerate only {sup 12}C{sup 6+} ions up to the energy of 430 MeV/u. It uses two normal conducting RF cavities. The RF frequency is about 70.76 MHz. The nominal dee voltage is 70 kV at the center and 160 kV at the extraction. The RF cavity was designed with 4 stems by using CST microwave studio (MWS). In this paper, we represent the simulation results and the optimized design of the RF cavity for the KIRAMS-430.
Studies of radioisotope production with an AVF cyclotron in TIARA
Energy Technology Data Exchange (ETDEWEB)
Sekine, Toshiaki [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment
1997-03-01
The production of radioisotopes to be used mainly for nuclear medicine and biology is studied with an AVF cyclotron in TIARA. A production method of no-carrier-added {sup 186}Re with the {sup 186}W(p,n){sup 186}Re reaction has been developed; this product may be used as a therapeutic agent in radioimmunotherapy due to the adequate nuclear and chemical properties. For the study of the function of plants using a positron-emitter two-dimensional imaging system, a simple method of producing the positron emitter {sup 18}F in water was developed by taking advantage of a highly-energetic {alpha} beam from the AVF cyclotron. (author)
Cyclotron resonance studies on InAs/GaSb heterostructures
Petchsingh, C
2002-01-01
Far-infrared cyclotron resonance is used to study the magneto-optical properties of semimetallic InAs/GaSb heterostructures. Spatially separated two-dimensional electron and hole gases coexist in this 'broken-gap' type-ll system due to charge transfer across the interfaces. Hybridisations of the overlapping electron and hole wavefunctions are investigated experimentally in samples of varying growth parameters. A self-consistent 8-band k centre dot p model is used to assist in the interpretation of experimental results. In samples subjected to varying magnetic field, hybridisations result in oscillations of cyclotron resonance mass, amplitude and linewidth, accompanied by transition splittings in the vicinity of Landau level anticrossings. Asymmetries introduced by InSb interface biasing enhance these effects. Comparison of samples with varying confinement energies (at specified magnetic field) shows effective mass enhancement greater than the standard nonparabolicity effect. The mass enhancement increases wit...
Physics of electron cyclotron current drive on DIII-D
Petty, C C; Harvey, R W; Kinsey, J E; Lao, L L; Lohr, J; Luce, T C; Makowski, M A; Prater, R
2002-01-01
OAK A271 PHYSICS OF ELECTRON CYCLOTRON CURRENT DRIVE ON DIII-D. Recent experiments on the DIII-D tokamak have focused on determining the effect of trapped particles on the electron cyclotron current drive (ECCD) efficiency. The measured ECCD efficiency increases as the deposition location is moved towards the inboard midplane or towards smaller minor radius for both co and counter injection. The measured ECCD efficiency also increases with increasing electron density and/or temperature. The experimental ECCD is compared to both the linear theory (Toray-GA) as well as a quasilinear Fokker-Planck model (CQL3D). The experimental ECCD is found to be in better agreement with the more complete Fokker-Planck calculation, especially for cases of high rf power density and/or loop voltage. The narrow width of the measured ECCD profile is consistent with only low levels of radial transport for the current carrying electrons.
Convexity and symmetrization in relativistic theories
Ruggeri, T.
1990-09-01
There is a strong motivation for the desire to have symmetric hyperbolic field equations in thermodynamics, because they guarantee well-posedness of Cauchy problems. A generic quasi-linear first order system of balance laws — in the non-relativistic case — can be shown to be symmetric hyperbolic, if the entropy density is concave with respect to the variables. In relativistic thermodynamics this is not so. This paper shows that there exists a scalar quantity in relativistic thermodynamics whose concavity guarantees a symmetric hyperbolic system. But that quantity — we call it —bar h — is not the entropy, although it is closely related to it. It is formed by contracting the entropy flux vector — ha with a privileged time-like congruencebar ξ _α . It is also shown that the convexity of h plus the requirement that all speeds be smaller than the speed of light c provide symmetric hyperbolic field equations for all choices of the direction of time. At this level of generality the physical meaning of —h is unknown. However, in many circumstances it is equal to the entropy. This is so, of course, in the non-relativistic limit but also in the non-dissipative relativistic fluid and even in relativistic extended thermodynamics for a non-degenerate gas.
The relativistic geoid: redshift and acceleration potential
Philipp, Dennis; Lämmerzahl, Claus; Puetzfeld, Dirk; Hackmann, Eva; Perlick, Volker
2017-04-01
We construct a relativistic geoid based on a time-independent redshift potential, which foliates the spacetime into isochronometric surfaces. This relativistic potential coincides with the acceleration potential for isometric congruences. We show that the a- and u- geoid, defined in a post-Newtonian framework, coincide also in a more general setup. Known Newtonian and post-Newtonian results are recovered in the respective limits. Our approach offers a relativistic definition of the Earth's geoid as well as a description of the Earth itself (or observers on its surface) in terms of an isometric congruence. Being fully relativistic, this notion of a geoid can also be applied to other compact objects such as neutron stars. By definition, this relativistic geoid can be determined by a congruence of Killing observers equipped with standard clocks by comparing their frequencies as well as by measuring accelerations of objects that follow the congruence. The redshift potential gives the correct result also for frequency comparison through optical fiber links as long as the fiber is at rest w.r.t. the congruence. We give explicit expressions for the relativistic geoid in the Kerr spacetime and the Weyl class of spacetimes. To investigate the influence of higher order mass multipole moments we compare the results for the Schwarzschild case to those obtained for the Erez-Rosen and q-metric spacetimes.
Electron Cyclotron Waves Polarization in the TJII Stellarator
Energy Technology Data Exchange (ETDEWEB)
Cappa, A.; Martinez-Fernandez, J.; Wagner, D.
2013-05-01
This report describes the theoretical calculations related with the electron cyclotron (EC) waves polarization control in the TJII stellarator. Two main aspects will be distinguished: the determination of the vacuum polarization that the wave must exhibit if a given propagation mode in a cold plasma is desired and the calculation of the behavior of the grooved polarizers and other transmission systems used to launch the vacuum wave with the required polarization. (Author) 13 refs.
Development of Production Procedure of 64Cu on Cyclotron
Institute of Scientific and Technical Information of China (English)
LIANG; Ji-xin; CHEN; Yu-qing; LI; Guang; DENG; Xue-song; SHEN; Yi-jia; QIAO; Lai-cheng; LIU; Yu-ping; JIANG; Hua; LI; Gui-qun
2013-01-01
Due to intermediate half-life(12.7 h)and favourable coordination chemistry,64Cu is an important emerging medical radionuclide that is suitable for labeling a wide range of radiopharmaceuticals for PET imaging and radiotherapy of tumor.The aim of this study is to develop the procedure for 64Cu production on Cyclone-30 cyclotron providing energy from 15-30 MeV.
Heavy ion beam transmission in the AGOR cyclotron
Sen, Ayanangsha
2013-01-01
In the framework of the TRImP program initiated at the KVI in 2002, the AGOR cyclotron was used to accelerate low energy heavy ion beams up to a beam intensity (>=10^12 particles per second). Typical beam ions are: 206Pb accelerated to 8 MeV/amu and 20Ne accelerated to 25 MeV/amu. In the course of b
Multimegawatt DAE$\\delta$ALUS Cyclotrons for Neutrino Physics
Abs, M; Alonso, J R; Barletta, W A; Barlow, R; Calabretta, L; Calanna, A; Campo, D; Celona, L; Conrad, J M; Gammino, S; Kleeven, W; Koeth, T; Maggiore, M; Okuno, H; Piazza, L A C; Seidel, M; Shaevitz, M H; Stingelin, L; Yang, J J; Yeck, J
2012-01-01
DAE$\\delta$ALUS (Decay-At-rest Experiment for $\\delta_{CP}$ studies At the Laboratory for Underground Science) provides a new approach to the search for CP violation in the neutrino sector. High-power continuous-wave proton cyclotrons efficiently provide the necessary proton beams with an energy of up to 800 MeV to create neutrinos from pion and muon decay-at-rest. The experiment searches for $\\bar{\
Design options for an ITER ion cyclotron system
Swain, D. W.; Baity, F. W.; Bigelow, T. S.; Ryan, P. M.; Goulding, R. H.; Carter, M. D.; Stallings, D. C.; Batchelor, D. B.; Hoffman, D. J.
1996-02-01
Recent changes have occurred in the design requirements for the ITER ion cyclotron system, requiring in-port launchers in four main horizontal ports to deliver 50 MW of power to the plasma. The design is complicated by the comparatively large antenna-separatrix distance of 10-20 cm. Designs of a conventional strap launcher and a folded waveguide launcher that can meet the new requirements are presented.
Design options for an ITER ion cyclotron system
Energy Technology Data Exchange (ETDEWEB)
Swain, D.W.; Baity, F.W.; Bigelow, T.S.; Ryan, P.M.; Goulding, R.H.; Carter, M.D.; Stallings, D.C.; Batchelor, D.B.; Hoffman, D.J. [Oak Ridge National Laboratory, P.O. Box 2009, Oak Ridge, Tennessee 37831 (United States)
1996-02-01
Recent changes have occurred in the design requirements for the ITER ion cyclotron system, requiring in-port launchers in four main horizontal ports to deliver 50 MW of power to the plasma. The design is complicated by the comparatively large antenna-separatrix distance of 10{endash}20 cm. Designs of a conventional strap launcher and a folded waveguide launcher that can meet the new requirements are presented. {copyright} {ital 1996 American Institute of Physics.}
Design options for an ITER ion cyclotron system
Energy Technology Data Exchange (ETDEWEB)
Swain, D.W.; Baity, F.W.; Bigelow, T.S.; Ryan, P.M.; Goulding, R.H.; Carter, M.D.; Stallings, D.C.; Batchelor, D.B.; Hoffman, D.J.
1995-09-01
Recent changes have occurred in the design requirements for the ITER ion cyclotron system, requiring in-port launchers in four main horizontal ports to deliver 50 MW of power to the plasma. The design is complicated by the comparatively large antenna-separatrix distance of 10--20 cm. Designs of a conventional strap launcher and a folded waveguide launcher than can meet the new requirements are presented.
Coaxial Ring Cyclotron as a Perspective Nuclear Power Engineering Machine
Tumanyan, A. R.; Simonyan, Kh. A.; Mkrtchyan, R. L.; Amatuni, A. Ts.; Avakyan, R. O.; Khudaverdyan, A. G.
1995-01-01
The circuit arrangement of the proposed coaxial ring cyclotron (CRC) is described, and its main advantages, such as simple injection technique, several injected beams summation option, high efficiency, are considered. The proposed proton accelerator is a perspective machine for the solution of the main problems of the present day nuclear power engineering as well as for the next-generation nuclear power plants, representing a combination of subcritical reactors and particle accelerators. The ...