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.
Su, Zhenpeng; Zhu, Hui; Xiao, Fuliang; Zheng, Huinan; Shen, Chao; Wang, Yuming; Wang, Shui
2013-06-01
Electromagnetic ion cyclotron (EMIC) waves are long suggested to account for the rapid loss of radiation belt relativistic electrons. Here we perform both theoretical analysis and numerical simulation to comprehensively investigate the nonlinear interaction between EMIC wave and relativistic electrons. In particular, we emphasize the dependence of nonlinear processes on the electron initial latitude. The nonlinear phase trapping yields negative equatorial pitch angle transport, with efficiency varying over the electron initial latitude, implying that it can increase the loss rate predicted by quasilinear theory. The nonlinear channel effect phase bunching produces positive equatorial pitch angle transport, less dependent on the electron initial latitude, suggesting that it can decrease the loss rate predicted by quasilinear theory. The nonlinear cluster effect phase bunching alternately causes positive and negative equatorial pitch angle transport, quasi-periodically dependent on the electron initial latitude, suggesting that it can either decrease or increase the loss rate predicted by the quasilinear theory. Such latitudinal dependence of nonlinear processes should be taken into account in the evaluation of radiation belt electron loss rate driven by EMIC waves.
Relativistic Cyclotron Resonance Shape in Magnetic Bottle Geonium
Dehmelt, Hans; Mittleman, Richard; Liu, Yuan
1988-10-01
The thermally excited axial oscillation of the electron through the weak magnetic bottle needed for the continuous Stern-Gerlach effect modulates the cyclotron frequency and produces a characteristic ≈ 12-kHz-wide vertical rise-exponential decline line shape of the cyclotron resonance. At the same time the relativistic mass shift decreases the frequency by ≈ 200 Hz per cyclotron motion quantum level n. Nevertheless, our analysis of the complex line shape shows that it should be possible to produce an abrupt rise in the cyclotron quantum number n from 0 to ≈ 20 over a small fraction of 200 Hz, when the 160-GHz microwave drive approaches the n = 0 → 1 transition, and a jump of 14 levels over a frequency increment of 200 Hz has already been observed in preliminary work. This realizes an earlier proposal to generate a very sharp cyclotron resonance feature by quasithermal excitation with a square noise band and should provide a way to detect spin flips when a weak bottle is used to reduce the broadening of the g - 2 resonance by a factor of 20.
Radiation surveillance in and around cyclotron facility
Kaur, Amandeep; Sharma, Sarika; Mittal, BR
2012-01-01
The cyclotron is the most widely used particle accelerator for producing medically important radio nuclides. Many medical centers in India have installed compact medical cyclotrons for on-site production of short-lived positron-emitting radio nuclides such as 18F, 13N, and 11C. A mandatory requirement for cyclotron installation is radiation control permit from Atomic Energy Regulatory Board. Cyclotron radiation survey is an integral part of the overall radiation safety in the cyclotron facility. Radiation surveillance in and around a newly installed cyclotron was performed using ionization chamber counter and Geiger Muller counter before, during and after operating the cyclotron. The readings were recorded at various locations where a high radiation field was expected. The results were recorded, tabulated and analyzed. The highest exposure level (0.93 μSv) was found at the back wall of the radiochemistry lab facing the cyclotron vault. Reason for the high exposure of 0.93 μSv/h: Synthesis of 18F-Fluoro-Deoxy-Glucose (18F-FDG) was going in the synthesis module and activity (18F) was present in the synthesis module when reading was taken. All other values were found to be below the recommended levels of exposure. PMID:24019654
Diffraction radiation from relativistic particles
Potylitsyn, Alexander Petrovich; Strikhanov, Mikhail Nikolaevich; Tishchenko, Alexey Alexandrovich
2010-01-01
This book deals with diffraction radiation, which implies the boundary problems of electromagnetic radiation theory. Diffraction radiation is generated when a charged particle moves in a vacuum near a target edge. Diffraction radiation of non-relativistic particles is widely used to design intense emitters in the cm wavelength range. Diffraction radiation from relativistic charged particles is important for noninvasive beam diagnostics and design of free electron lasers based on Smith-Purcell radiation which is diffraction radiation from periodic structures. Different analytical models of diffraction radiation and results of recent experimental studies are presented in this book. The book may also serve as guide to classical electrodynamics applications in beam physics and electrodynamics. It can be of great use for young researchers to develop skills and for experienced scientists to obtain new results.
Radiation reaction and relativistic hydrodynamics.
Berezhiani, V I; Hazeltine, R D; Mahajan, S M
2004-05-01
By invoking the radiation reaction force, first perturbatively derived by Landau and Lifschitz, and later shown by Rohrlich to be exact for a single particle, we construct a set of fluid equations obeyed by a relativistic plasma interacting with the radiation field. After showing that this approach reproduces the known results for a locally Maxwellian plasma, we derive and display the basic dynamical equations for a general magnetized plasma in which the radiation reaction force augments the direct Lorentz force.
Long-term cyclotron dynamics of relativistic wave packets: Spontaneous collapse and revival
Demikhovskii, V. Ya.; Maksimova, G. M.; Perov, A. A.; Telezhnikov, A. V.
2012-02-01
In this work we study the effects of collapse and revival, as well as the zitterbewegung (ZB) phenomenon, for the relativistic electron wave packets, which are a superposition of the states with quantum numbers sharply peaked around some Landau level n0 of the order of few tens. The probability densities as well as average velocities of the packet center and the average spin components were calculated analytically and their evolution is visualized. Our computations demonstrate that due to the dephasing of the states for times larger than the cyclotron period the initial wave packet (which includes the states with the positive energy only) loses the spatial localization so that the evolution can no longer be described classically. However, at the half-revival time t=TR/2 its reshaping takes place first. It is shown that the behavior of the wave packet containing the states of both energy bands (with En>0 and Ennegative energy) restores at various points of the cyclotron orbit, which makes reshaping of the initial wave packet impossible, entirely unlike the wave packet which consists of states with energies En>0 only. The obtained results can be useful for the description of electromagnetic radiation and absorption in relativistic plasma on astrophysics objects, where superhigh magnetic field has a value of the order 108-109T, as well as for interpretation of experiments with trapped ions.
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.
Rapid Loss of Radiation Belt Relativistic Electrons by EMIC Waves
Su, Zhenpeng; Gao, Zhonglei; Zheng, Huinan; Wang, Yuming; Wang, Shui; Spence, H. E.; Reeves, G. D.; Baker, D. N.; Wygant, J. R.
2017-10-01
How relativistic electrons are lost is an important question surrounding the complex dynamics of the Earth's outer radiation belt. Radial loss to the magnetopause and local loss to the atmosphere are two main competing paradigms. Here on the basis of the analysis of a radiation belt storm event on 27 February 2014, we present new evidence for the electromagnetic ion cyclotron (EMIC) wave-driven local precipitation loss of relativistic electrons in the heart of the outer radiation belt. During the main phase of this storm, the radial profile of relativistic electron phase space density was quasi-monotonic, qualitatively inconsistent with the prediction of radial loss theory. The local loss at low L shells was required to prevent the development of phase space density peak resulting from the radial loss process at high L shells. The rapid loss of relativistic electrons in the heart of outer radiation belt was observed as a dip structure of the electron flux temporal profile closely related to intense EMIC waves. Our simulations further confirm that the observed EMIC waves within a quite limited longitudinal region were able to reduce the off-equatorially mirroring relativistic electron fluxes by up to 2 orders of magnitude within about 1.5 h.
Radiation Hazard of Relativistic Interstellar Flight
Semyonov, Oleg G.
2006-01-01
From the point of view of radiation safety, interstellar space is not an empty void. Interstellar gas and cosmic rays, which consist of hydrogen and helium nucleons, present a severe radiation hazard to crew and electronics aboard a relativistic interstellar ship. Of the two, the oncoming relativistic flow of interstellar gas produces the most intence radiation. A protection shield will be needed to block relativistic interstellar gas that can also absorb most of the cosmic rays which, as a r...
Relativistic Cyclotron Resonance Shape in Magnetic Bottle Geonium
National Research Council Canada - National Science Library
Hans Dehmelt; Richard Mittleman; Yuan Liu
1988-01-01
The thermally excited axial oscillation of the electron through the weak magnetic bottle needed for the continuous Stern-Gerlach effect modulates the cyclotron frequency and produces a characteristic...
Radiatively-driven general relativistic jets
Indian Academy of Sciences (India)
Mukesh K. Vyas
2018-02-10
Feb 10, 2018 ... of radial jets and solve them using polytropic equation of state of the relativistic gas. We consider curved space- time around black holes and obtain jets with moderately relativistic terminal speeds. In addition, the radiation field from the accretion disc, is able to induce internal shocks in the jet close to the ...
Synchrotron Radiation From Plasmas with Sub-Relativistic Temperatures
Necas, Ales; Putvinski, Sergei; Ryutov, Dmitri; Yushmanov, Peter; TAE Team
2017-10-01
A simple expression for power radiated by synchrotron radiation from plasmas with electron temperatures between 50 - 200 keV is developed. We shall start by re-deriving a general expression for power radiated in vacuum from an individual cyclotron harmonic. Adding up power radiated from individual harmonics shows an asymptotic approach to the power radiated from all harmonics. In a case of Te =50 keV, summing the first 10 harmonics well represents radiation from all harmonics. However, for Te =150 keV, we require to sum over 60 harmonics to adequately represent the total radiation. This is computationally demanding. What follows is a derivation of a simple expression for high harmonic power radiation in vacuum. It is of interested that this expression proofs to be reasonable even for low harmonic numbers. Next we shall present the derivation of the relativistic frequency spectra. A discussion of cut-off for the electromagnetic O-wave and X-wave follows as well as re-emission of synchrotron radiation. Wave propagation close to perpendicular to B field is assumed.
Theory of relativistic radiation reflection from plasmas
Gonoskov, Arkady
2018-01-01
We consider the reflection of relativistically strong radiation from plasma and identify the physical origin of the electrons' tendency to form a thin sheet, which maintains its localisation throughout its motion. Thereby, we justify the principle of relativistic electronic spring (RES) proposed in [Gonoskov et al., Phys. Rev. E 84, 046403 (2011)]. Using the RES principle, we derive a closed set of differential equations that describe the reflection of radiation with arbitrary variation of polarization and intensity from plasma with an arbitrary density profile for an arbitrary angle of incidence. We confirm with ab initio PIC simulations that the developed theory accurately describes laser-plasma interactions in the regime where the reflection of relativistically strong radiation is accompanied by significant, repeated relocation of plasma electrons. In particular, the theory can be applied for the studies of plasma heating and coherent and incoherent emissions in the RES regime of high-intensity laser-plasma interaction.
Radiation Monitoring System of 30 MeV Cyclotron
Directory of Open Access Journals (Sweden)
Lee Jin-Woo
2017-01-01
Full Text Available 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.
Sakharov, A. S.
2017-11-01
Compact expressions are derived for the nonlocal permittivity tensor of weakly relativistic plasma in a 2D nonuniform magnetic field near the resonances at the second harmonic of the electron cyclotron frequency for an extraordinary wave and at the first harmonic for an ordinary wave. It is shown that the wave equation with allowance for the obtained thermal correction to the permittivity tensor in the form of a differential operator in transverse (with respect to the external magnetic field) coordinates possesses an integral in the form of the energy conservation law.
A relativistic model of electron cyclotron current drive efficiency in tokamak plasmas
Directory of Open Access Journals (Sweden)
Lin-Liu Y.R.
2012-09-01
Full Text Available 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 has generalized that of Marushchenko’s (N.B . Marushchenko, et al. Fusion Sci. & Tech., 2009, which is extended for arbitrary temperatures and covers exactly the asymptotic for u ≫ 1 when Z → ∞, and suitable for ray-tracing calculations.
Relativistically strong electromagnetic radiation in a plasma
Bulanov, S. V.; Esirkepov, T. Zh.; Kando, M.; Kiriyama, H.; Kondo, K.
2016-03-01
Physical processes in a plasma under the action of relativistically strong electromagnetic waves generated by high-power lasers have been briefly reviewed. These processes are of interest in view of the development of new methods for acceleration of charged particles, creation of sources of bright hard electromagnetic radiation, and investigation of macroscopic quantum-electrodynamical processes. Attention is focused on nonlinear waves in a laser plasma for the creation of compact electron accelerators. The acceleration of plasma bunches by the radiation pressure of light is the most efficient regime of ion acceleration. Coherent hard electromagnetic radiation in the relativistic plasma is generated in the form of higher harmonics and/or electromagnetic pulses, which are compressed and intensified after reflection from relativistic mirrors created by nonlinear waves. In the limit of extremely strong electromagnetic waves, radiation friction, which accompanies the conversion of radiation from the optical range to the gamma range, fundamentally changes the behavior of the plasma. This process is accompanied by the production of electron-positron pairs, which is described within quantum electrodynamics theory.
Cao, Xing; Shprits, Yuri Y; Ni, Binbin; Zhelavskaya, Irina S
2017-12-18
Electron flux in the Earth's outer radiation belt is highly variable due to a delicate balance between competing acceleration and loss processes. It has been long recognized that Electromagnetic Ion Cyclotron (EMIC) waves may play a crucial role in the loss of radiation belt electrons. Previous theoretical studies proposed that EMIC waves may account for the loss of the relativistic electron population. However, recent observations showed that while EMIC waves are responsible for the significant loss of ultra-relativistic electrons, the relativistic electron population is almost unaffected. In this study, we provide a theoretical explanation for this discrepancy between previous theoretical studies and recent observations. We demonstrate that EMIC waves mainly contribute to the loss of ultra-relativistic electrons. This study significantly improves the current understanding of the electron dynamics in the Earth's radiation belt and also can help us understand the radiation environments of the exoplanets and outer planets.
Cao, Xing; Shprits, Yuri Y.; Ni, Binbin; Zhelavskaya, Irina S.
2017-01-01
Electron flux in the Earth’s outer radiation belt is highly variable due to a delicate balance between competing acceleration and loss processes. It has been long recognized that Electromagnetic Ion Cyclotron (EMIC) waves may play a crucial role in the loss of radiation belt electrons. Previous theoretical studies proposed that EMIC waves may account for the loss of the relativistic electron population. However, recent observations showed that while EMIC waves are responsible for the signific...
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.
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.
Cyclotron Resonance Gain for FIR and THz Radiation in Graphene
Cole, Nightvid
2016-01-01
A cyclotron resonance maser source using low-effective-mass conduction electrons in graphene, if successful, would allow for generation of Far Infrared (FIR) and Terahertz (THz) radiation without requiring magnetic fields running into the tens of Tesla. In order to investigate this possibility, we consider a device in which electrons are effectively injected via pumping from the valence band to the conduction band using an infrared (IR) laser source, subsequently gyrate in a magnetic field applied perpendicular to the plane of the graphene, and give rise to gain for a FIR/THz wave crossing the plane of the graphene. A set of integral expressions is derived by assuming that the non-radiative energy loss processes of the electrons can be adequately represented by a damping force proportional and antiparallel to their momentum. Minimal gain may occur at very short electron damping times of hundreds of femtoseconds.
Explaining the Dynamics of the Ultra-relativistic Third Van Allen Radiation Belt
Mann, I. R.; Ozeke, L.; Murphy, K. R.; Claudepierre, S. G.; Turner, D. L.; Baker, D. N.; Rae, 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.
2016-12-01
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 losses deep in the heart of the belt which lead to the recently discovered ultra-relativistic third electron radiation belt. Prior theory asserted 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 can be 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.
Fuerst, Steven V.; Mizuno, Yosuke; Nishikawa, Ken-Ichi; Wu, Kinwah
2007-01-01
We have calculated the emission from relativistic flows in black hole systems using a fully general relativistic radiative transfer, with flow structures obtained by general relativistic magnetohydrodynamic simulations. We consider thermal free-free emission and thermal synchrotron emission. Bright filament-like features are found protruding (visually) from the accretion disk surface, which are enhancements of synchrotron emission when the magnetic field is roughly aligned with the line-of-sight in the co-moving frame. The features move back and forth as the accretion flow evolves, but their visibility and morphology are robust. We propose that variations and location drifts of the features are responsible for certain X-ray quasi-periodic oscillations (QPOs) observed in black-hole X-ray binaries.
Coherent radiation of relativistic electrons in dielectric fibers
Energy Technology Data Exchange (ETDEWEB)
Naumenko, G., E-mail: naumenko@tpu.ru; Potylitsyn, A.; Bleko, V.; Soboleva, V.
2015-07-15
The properties of different types of radiation, such as diffraction and Cherenkov radiation, induced by an electromagnetic field of a relativistic electron in optical fibers were calculated by Artru and Ray (2013). These authors have showed a difference of the considered radiation from the traditional radiation mechanisms, such as transition and diffraction radiation. In this paper we present the results of experimental investigations of this phenomenon in millimeter wavelength region. The spectral characteristics and radiation yield depending on the impact-parameter of fibers relative to the electron beam were investigated and compared with backward diffraction radiation for similar conditions. The influence of a fiber curvature on the generated radiation transmission in agreement with theoretical prediction was shown. The role of evanescent waves in the radiation generation and transport in fibers was experimentally investigated using the millimeter wavelength emitter.
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.
Radiation of relativistic electrons in a periodic wire structure
Energy Technology Data Exchange (ETDEWEB)
Soboleva, V.V., E-mail: sobolevaveronica@mail.ru; Naumenko, G.A.; Bleko, V.V.
2015-07-15
We present in this work the experimental investigation of the interaction of relativistic electron field with periodic wire structures. We used two types of the targets in experiments: flat wire target and sandwich wire target that represent the right triangular prism. The measurements were done in millimeter wavelength region (10–40 mm) on the relativistic electron beam with energy of 6.2 MeV in far-field zone. We showed that bunched electron beam passing near wire metamaterial prism generates coherent Cherenkov radiation. The experiments with flat wire target were carried out in two geometries. In the first geometry the electron beam passed close to the flat wire target surface. In the second case the electron beam passed through the flat wire structure with generation of a coherent backward transition radiation (CBTR). The comparison of the Cherenkov radiation intensity and BTR intensity from the flat wire target and from the flat conductive target (conventional BTR) was made.
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.
Cao, Xing; Ni, Binbin; Summers, Danny; Zou, Zhengyang; Fu, Song; Zhang, Wenxun
2017-10-01
Bounce resonant interactions with magnetospheric waves have been proposed as an important contributing mechanism for scattering near-equatorially mirroring electrons by violating the second adiabatic invariant associated with the electron bounce motion along a geomagnetic field line. This study demonstrates that low-frequency plasmaspheric hiss with significant wave power below 100 Hz can bounce resonate efficiently with radiation belt electrons. By performing quantitative calculations of pitch angle scattering rates, we show that low-frequency hiss-induced bounce resonant scattering of electrons has a strong dependence on equatorial pitch angle αeq. For electrons with αeq close to 90°, the timescale associated with bounce resonance scattering can be comparable to or even less than 1 h. Cyclotron and Landau resonant interactions between low-frequency hiss and electrons are also investigated for comparisons. It is found that while the bounce and Landau resonances are responsible for the diffusive transport of near-equatorially mirroring electrons to lower αeq, pitch angle scattering by cyclotron resonance could take over to further diffuse electrons into the atmosphere. Bounce resonance provides a more efficient pitch angle scattering mechanism of relativistic (≥1 MeV) electrons than Landau resonance due to the stronger scattering rates and broader resonance coverage of αeq, thereby demonstrating that bounce resonance scattering by low-frequency hiss can contribute importantly to the evolution of the electron pitch angle distribution and the loss of radiation belt electrons.
Radiative cooling of relativistic electron beams
Energy Technology Data Exchange (ETDEWEB)
Huang, Zhirong [Stanford Univ., CA (United States)
1998-05-01
Modern high-energy particle accelerators and synchrotron light sources demand smaller and smaller beam emittances in order to achieve higher luminosity or better brightness. For light particles such as electrons and positrons, radiation damping is a natural and effective way to obtain low emittance beams. However, the quantum aspect of radiation introduces random noise into the damped beams, yielding equilibrium emittances which depend upon the design of a specific machine. In this dissertation, the author attempts to make a complete analysis of the process of radiation damping and quantum excitation in various accelerator systems, such as bending magnets, focusing channels and laser fields. Because radiation is formed over a finite time and emitted in quanta of discrete energies, he invokes the quantum mechanical approach whenever the quasiclassical picture of radiation is insufficient. He shows that radiation damping in a focusing system is fundamentally different from that in a bending system. Quantum excitation to the transverse dimensions is absent in a straight, continuous focusing channel, and is exponentially suppressed in a focusing-dominated ring. Thus, the transverse normalized emittances in such systems can in principle be damped to the Compton wavelength of the electron, limited only by the Heisenberg uncertainty principle. In addition, he investigates methods of rapid damping such as radiative laser cooling. He proposes a laser-electron storage ring (LESR) where the electron beam in a compact storage ring repetitively interacts with an intense laser pulse stored in an optical resonator. The laser-electron interaction gives rise to rapid cooling of electron beams and can be used to overcome the space charge effects encountered in a medium energy circular machine. Applications to the designs of low emittance damping rings and compact x-ray sources are also explored.
Simulation of Relativistic Shocks and Associated Self-Consistent Radiation
Nishikawa, K.-I.; Niemiec, J.; Medvedev, M.; Zhang, B.; Hardee, P.; Mizuno, Y.; Nordlund, A.; Frederiksen, J.; Sol, H.; Pohl, M.;
2010-01-01
Plasma instabilities excited in collisionless shocks are responsible for particle acceleration. We have investigated the particle acceleration and shock structure associated with an unmagnetized relativistic electron-positron jet propagating into an unmagnetized electron-positron plasma. Cold jet electrons are thermalized and slowed while the ambient electrons are swept up to create a partially developed hydrodynamic-like shock structure. In the leading shock, electron density increases by a factor of about 3.5 in the simulation frame. Strong electromagnetic fields are generated in the trailing shock and provide an emission site. These magnetic fields contribute to the electrons transverse deflection behind the shock. We calculate the radiation from deflected electrons in the turbulent magnetic fields. The properties of this radiation may be important for understanding the complex time evolution and/or spectral structure in gamma-ray bursts, relativistic jets in general, and supernova remnants.
Scattering of Non-Relativistic Charged Particles by Electromagnetic Radiation
Apostol, M.
2017-11-01
The cross-section is computed for non-relativistic charged particles (like electrons and ions) scattered by electromagnetic radiation confined to a finite region (like the focal region of optical laser beams). The cross-section exhibits maxima at scattering angles given by the energy and momentum conservation in multi-photon absorption or emission processes. For convenience, a potential scattering is included and a comparison is made with the well-known Kroll-Watson scattering formula. The scattering process addressed in this paper is distinct from the process dealt with in previous studies, where the scattering is immersed in the radiation field.
Prakash, Bramha; Mishra, Ganeswar; Khullar, Roma
2016-03-01
In this paper spontaneous emission of radiation by relativistic electrons in a gyro-klystron is studied. The scheme consists of two solenoid sections separated by a dispersive section. In the dispersive section the electrons are made non-resonant with the radiation. The dispersive section transforms a small change of the velocity into changes of the phases of the electrons. This leads to enhanced radiation due to klystron-type modulation as compared with a conventional gyrotron-type device driven by cyclotron maser interaction. It is shown that the klystron-modulated spectrum depends on the dispersive field strength, finite perpendicular velocity component and length of the solenoids but is independent of the axial magnetic field strength. A simple scheme to design a gyro-klystron is discussed.
Results from the Project 8 phase-1 cyclotron radiation emission spectroscopy detector
Ashtari Esfahani, A.; Böser, S.; Claessens, C.; de Viveiros, L.; Doe, P. J.; Doeleman, S.; Fertl, M.; Finn, E. C.; Formaggio, J. A.; Guigue, M.; Heeger, K. M.; Jones, A. M.; Kazkaz, K.; LaRoque, B. H.; Machado, E.; Monreal, B.; Nikkel, J. A.; Oblath, N. S.; Robertson, R. G. H.; Rosenberg, L. J.; Rybka, G.; Saldaña, L.; Slocum, P. L.; Tedeschi, J. R.; Thümmler, T.; Vandevender, B. A.; Wachtendonk, M.; Weintroub, J.; Young, A.; Zayas, E.
2017-09-01
The Project 8 collaboration seeks to measure the absolute neutrino mass scale by means of precision spectroscopy of the beta decay of tritium. Our technique, cyclotron radiation emission spectroscopy, measures the frequency of the radiation emitted by electrons produced by decays in an ambient magnetic field. Because the cyclotron frequency is inversely proportional to the electron’s Lorentz factor, this is also a measurement of the electron’s energy. In order to demonstrate the viability of this technique, we have assembled and successfully operated a prototype system, which uses a rectangular waveguide to collect the cyclotron radiation from internal conversion electrons emitted from a gaseous 83m Kr source. Here we present the main design aspects of the first phase prototype, which was operated during parts of 2014 and 2015. We will also discuss the procedures used to analyze these data, along with the features which have been observed and the performance achieved to date.
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
Hembeck, J.; Lessard, M.; Engebretson, M. J.; Rodger, C. J.; Hendry, A.
2016-12-01
Electromagnetic Ion Cyclotron (EMIC) waves are phenomena that exist within the Earth's magnetosphere caused by an ion temperature anisotropy. The ideal conditions for EMIC wave growth occur during solar storms. In this statistical study, Polar Orbiting Environmental Satellites (POES) relativistic electron precipitation (REP) data are compared to EMIC wave data from Halley Bay in the years ranging from 2008-2010. This statistical study considers a specific type of EMIC wave events known as Intervals of Pulsations of Diminishing Periods (IPDP) to see whether this type of EMIC wave causes a statistically greater occurrence of REP. In this study, different types of IPDP are characterized based on the increase in frequency over time of each wave form. Another considered characteristic of the IPDP waves is whether the wave is continuous or appears as discrete packets, which may actually be separate events. IPDP events are cataloged and then compared to REP events from the POES data set, forming a study that is complementary to that of Hendry et al. [2016], who compared REP from POES data to the presence of EMIC waves at Halley Bay.
The 88-Inch Cyclotron: A One-Stop Facility for Electronics Radiation and Detector Testing
Energy Technology Data Exchange (ETDEWEB)
Kireeff Covo, M.; Albright, R. A.; Ninemire, B. F.; Johnson, M. B.; Hodgkinson, A.; Loew, T.; Benitez, J. Y.; Todd, D. S.; Xie, D. Z.; Perry, T.; Phair, L.; Bernsteiny, L. A.; Bevins, J.; Brown, J. A.; Goldblum, B. L.; Harasty, M.; Harrig, K. P.; Laplace, T. A.; Matthews, E. F.; Bushmaker, A.; Walker, D.; Oklejas, V.; Hopkins, A. R.; Bleuel, D. L.; Chen, J.; Cronin, S. B.
2017-10-01
In outer space down to the altitudes routinely flown by larger aircrafts, radiation can pose serious issues for microelectronics circuits. The 88-Inch Cyclotron at Lawrence Berkeley National Laboratory is a sector-focused cyclotron and home of the Berkeley Accelerator Space Effects Facility, where the effects of energetic particles on sensitive microelectronics are studied with the goal of designing electronic systems for the space community. This paper describes the flexibility of the facility and its capabilities for testing the bombardment of electronics by heavy ions, light ions, and neutrons. Experimental capabilities for the generation of neutron beams from deuteron breakups and radiation testing of carbon nanotube field effect transistor will be discussed.
Energy Technology Data Exchange (ETDEWEB)
Sandanger, Marit Irene J.
2009-07-01
The main objective was to study the losses of energetic particles in the magnetosphere during geomagnetic active periods. Considerable attention has been given to the dynamics of relativistic electrons in the inner magnetosphere during geomagnetic active times. Modern life depends on satellite observations and communications, and large enhancements of radiation belt electron fluxes can cause serious problems as they can damage the hardware onboard spacecraft causing system anomalies or complete failure. Precipitating relativistic electrons can also penetrate deep into the atmosphere and affect the ozone layer. During geomagnetic storms, the flux of radiation belt electrons can increase, decrease, or stay constant depending on the mechanism of acceleration and loss of the electrons. Radiation belt particles have traditionally been studied with data from geostationary satellites. In this thesis polar orbiting satellites that orbit the Earth at low altitude has been used. Energetic particles detected at high latitudes reflect the population in the outer part of the radiation belts and ring current, while the particles detected at lower latitudes reflect the population in the inner part of the radiation belts and ring current. The large database of particle data from the National Oceanic and Atmospheric Administration (NOAA) Polar Orbiting Environmental Satellites (POES) has been used. These orbit the Earth approximately 15 times each day at low altitude (around 850 km above the surface). The NOAA POES satellites orbit the Earth at different local times and the local time resolution is thus dependent on the number of satellites in orbit. Their orbital time are around 100 minutes. They are mainly weather satellites but are also a part of the Search and Rescue Satellite-Aided Tracking (SARSAT). Measurements from the Space Environment Monitor (SEM) instrument package which was first mounted on TIROS-N (Television and Infrared Observation Satellite) in 1978 as version SEM
Relativistic nonlinear electrodynamics the QED vacuum and matter in super-strong radiation fields
Avetissian, Hamlet K
2016-01-01
This revised edition of the author’s classic 2006 text offers a comprehensively updated review of the field of relativistic nonlinear electrodynamics. It explores the interaction of strong and super-strong electromagnetic/laser radiation with the electromagnetic quantum vacuum and diverse types of matter – including free charged particles and antiparticles, acceleration beams, plasma and plasmous media. The appearance of laser sources of relativistic and ultra-relativistic intensities over the last decade has stimulated investigation of a large class of processes under such super-strong radiation fields. Revisions for this second edition reflect these developments and the book includes new chapters on Bremsstrahlung and nonlinear absorption of superintense radiation in plasmas, the nonlinear interaction of relativistic atoms with intense laser radiation, nonlinear interaction of strong laser radiation with Graphene, and relativistic nonlinear phenomena in solid-plasma targets under supershort laser pul...
A cyclotron isotope production facility designed to maximize production and minimize radiation dose
Dickie, W. J.; Stevenson, N. R.; Szlavik, F. F.
1993-06-01
Continuing increases in requirements from the nuclear medicine industry for cyclotron isotopes is increasing the demands being put on an aging stock of machines. In addition, with the 1990 recommendations of the ICRP publication in place, strict dose limits will be required and this will have an effect on the way these machines are being operated. Recent advances in cyclotron design combined with lessons learned from two decades of commercial production mean that new facilities can result in a substantial charge on target, low personnel dose, and minimal residual activation. An optimal facility would utilize a well engineered variable energy/high current H - cyclotron design, multiple beam extraction, and individual target caves. Materials would be selected to minimize activation and absorb neutrons. Equipment would be designed to minimize maintenance activities performed in high radiation fields.
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).
Smolyakov, M N
2000-01-01
This paper deals with electromagnetic radiation generated by relativistic particles in arbitrary planar magnetic field (in undulator for example). Magnetic system producing this field is assumed to be planar consisting of permanent magnets. It is shown that there is a special class of magnetic moment rotations in such system while magnetic field is varying but spontaneous radiation spectrum generated by relativistic particles remains the same. This property of electromagnetic radiation can be used in designing new undulators.
Zhevago, N. K.; Glebov, V. I.
2017-06-01
We have developed the theory of electromagnetic interaction of relativistic charged particles with metal-organic frameworks (MOFs). The electrostatic potential and electron number density distribution in MOFs were calculated using the most accurate data for the atomic form factors. Peculiarities of axial channeling of fast charged particles and various types of electromagnetic radiation from relativistic particles has been discussed.
Ultra-low-frequency wave-driven diffusion of radiation belt relativistic electrons.
Su, Zhenpeng; Zhu, Hui; Xiao, Fuliang; Zong, Q-G; Zhou, X-Z; Zheng, Huinan; Wang, Yuming; Wang, Shui; Hao, Y-X; Gao, Zhonglei; He, Zhaoguo; Baker, D N; Spence, H E; Reeves, G D; Blake, J B; Wygant, J R
2015-12-22
Van Allen radiation belts are typically two zones of energetic particles encircling the Earth separated by the slot region. How the outer radiation belt electrons are accelerated to relativistic energies remains an unanswered question. Recent studies have presented compelling evidence for the local acceleration by very-low-frequency (VLF) chorus waves. However, there has been a competing theory to the local acceleration, radial diffusion by ultra-low-frequency (ULF) waves, whose importance has not yet been determined definitively. Here we report a unique radiation belt event with intense ULF waves but no detectable VLF chorus waves. Our results demonstrate that the ULF waves moved the inner edge of the outer radiation belt earthward 0.3 Earth radii and enhanced the relativistic electron fluxes by up to one order of magnitude near the slot region within about 10 h, providing strong evidence for the radial diffusion of radiation belt relativistic electrons.
Relativistic transformation of phase-space distributions
Directory of Open Access Journals (Sweden)
R. A. Treumann
2011-07-01
Full Text Available We investigate the transformation of the distribution function in the relativistic case, a problem of interest in plasma when particles with high (relativistic velocities come into play as for instance in radiation belt physics, in the electron-cyclotron maser radiation theory, in the vicinity of high-Mach number shocks where particles are accelerated to high speeds, and generally in solar and astrophysical plasmas. We show that the phase-space volume element is a Lorentz constant and construct the general particle distribution function from first principles. Application to thermal equilibrium lets us derive a modified version of the isotropic relativistic thermal distribution, the modified Jüttner distribution corrected for the Lorentz-invariant phase-space volume element. Finally, we discuss the relativistic modification of a number of plasma parameters.
The electron-cyclotron maser instability as a source of plasma radiation. [Solar radio bursts
Winglee, R. M.; Dulk, G. A.
1986-01-01
The generation of continuum bursts from the sun at dm and m wavelengths (in particular, type IV bursts) via the electron-cyclotron-maser instability is examined. The maser instability can be driven by an electron distribution with either a loss-cone anisotropy or a peak at large pitch angles. For omega(p)/Omega(e) much greater than 1, the maser emission is produced by electrons interacting through a harmonic (cyclotron) resonance and is electrostatic, being in the upper hybrid mode at frequencies approximately equal to omega(p). Coalescence processes are required to convert the electrostatic waves into transverse radiation which can escape from the source region. Whether the resultant spectrum is nearly a smooth continuum or has a zebra-stripe pattern (both of which occur in type IV bursts) depends on the form of the electron distribution, inhomogeneities in the density and magnetic field, and whether the maser reaches saturation. For at least the case of some type IV dm bursts with fine structure, comparison with observations seems to indicate that the electrons producing the emission are more likely to have a loss-cone distribution, and that the maser instability is not at saturation.
Tang, C. L.; Wang, Y. X.; Ni, B.; Su, Z. P.; Reeves, G. D.; Zhang, J.-C.; Baker, D. N.; Spence, H. E.; Funsten, H. O.; Blake, J. B.
2017-10-01
Using the electron phase space density (PSD) data measured by Van Allen Probe A from January 2013 to April 2015, we investigate the effects of magnetospheric processes on relativistic electron dynamics in the Earth's outer radiation belt during 50 geomagnetic storms. A statistical study shows that the maximum electron PSDs for various μ (μ = 630, 1096, 2290, and 3311 MeV/G) at L* 4.0 after the storm peak have good correlations with storm intensity (cc 0.70). This suggests that the occurrence and magnitude of geomagnetic storms are necessary for relativistic electron enhancements at the inner edge of the outer radiation belt (L* = 4.0). For moderate or weak storm events (SYM-Hmin > -100 nT) with weak substorm activity (AEmax 0.77). For storm events with intense substorms after the storm peak, relativistic electron enhancements at L* = 4.5 and 5.0 are observed. This shows that intense substorms during the storm recovery phase are crucial to relativistic electron enhancements in the heart of the outer radiation belt. Our statistics study suggests that magnetospheric processes during geomagnetic storms have a significant effect on relativistic electron dynamics.
Synchrotron Radiation Maps from Relativistic MHD Jet Simulations
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Dimitrios Millas
2017-11-01
Full Text Available Relativistic jets from active galactic nuclei (AGN often display a non-uniform structure and are, under certain conditions, susceptible to a number of instabilities. An interesting example is the development of non-axisymmetric, Rayleigh-Taylor type instabilities in the case of differentially rotating two-component jets, with the toroidal component of the magnetic field playing a key role in the development or suppression of these instabilities. We have shown that higher magnetization leads to stability against these non-axisymmetric instabilities. Using ray-casting on data from relativistic MHD simulations of two-component jets, we now investigate the effect of these instabilities on the synchrotron emission pattern from the jets. We recover many well known trends from actual observations, e.g., regarding the polarization fraction and the distribution of the position angle of the electric field, in addition to a different emitting region, depending on the stability of the jet.
Kersten, K.; Cattell, C. A.; Breneman, A.; Goetz, K.; Kellogg, P. J.; Wygant, J. R.; Wilson, L. B., III; Blake, J. B.; Looper, M. D.; Roth, I.
2011-01-01
We present multi-satellite observations of large amplitude radiation belt whistler-mode waves and relativistic electron precipitation. On separate occasions during the Wind petal orbits and STEREO phasing orbits, Wind and STEREO recorded intense whistler-mode waves in the outer nightside equatorial radiation belt with peak-to-peak amplitudes exceeding 300 mV/m. During these intervals of intense wave activity, SAMPEX recorded relativistic electron microbursts in near magnetic conjunction with Wind and STEREO. This evidence of microburst precipitation occurring at the same time and at nearly the same magnetic local time and L-shell with a bursty temporal structure similar to that of the observed large amplitude wave packets suggests a causal connection between the two phenomena. Simulation studies corroborate this idea, showing that nonlinear wave.particle interactions may result in rapid energization and scattering on timescales comparable to those of the impulsive relativistic electron precipitation.
HERO - A 3D general relativistic radiative post-processor for accretion discs around black holes
Zhu, Yucong; Narayan, Ramesh; Sadowski, Aleksander; Psaltis, Dimitrios
2015-08-01
HERO (Hybrid Evaluator for Radiative Objects) is a 3D general relativistic radiative transfer code which has been tailored to the problem of analysing radiation from simulations of relativistic accretion discs around black holes. HERO is designed to be used as a post-processor. Given some fixed fluid structure for the disc (i.e. density and velocity as a function of position from a hydrodynamic or magnetohydrodynamic simulation), the code obtains a self-consistent solution for the radiation field and for the gas temperatures using the condition of radiative equilibrium. The novel aspect of HERO is that it combines two techniques: (1) a short-characteristics (SC) solver that quickly converges to a self-consistent disc temperature and radiation field, with (2) a long-characteristics (LC) solver that provides a more accurate solution for the radiation near the photosphere and in the optically thin regions. By combining these two techniques, we gain both the computational speed of SC and the high accuracy of LC. We present tests of HERO on a range of 1D, 2D, and 3D problems in flat space and show that the results agree well with both analytical and benchmark solutions. We also test the ability of the code to handle relativistic problems in curved space. Finally, we discuss the important topic of ray defects, a major limitation of the SC method, and describe our strategy for minimizing the induced error.
Ultra-low-frequency wave-driven diffusion of radiation belt relativistic electrons
Su, Zhenpeng; Zhu, Hui; Xiao, Fuliang; Zong, Q.-G.; Zhou, X.-Z.; Zheng, Huinan; Wang, Yuming; Wang, Shui; Hao, Y.-X.; Gao, Zhonglei; He, Zhaoguo; Baker, D. N.; Spence, H. E.; Reeves, G. D.; Blake, J. B.
2015-01-01
Van Allen radiation belts are typically two zones of energetic particles encircling the Earth separated by the slot region. How the outer radiation belt electrons are accelerated to relativistic energies remains an unanswered question. Recent studies have presented compelling evidence for the local acceleration by very-low-frequency (VLF) chorus waves. However, there has been a competing theory to the local acceleration, radial diffusion by ultra-low-frequency (ULF) waves, whose importance ha...
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.
2016-01-01
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,...
Local Smooth Solution and Non-Relativistic Limit of Radiation Hydrodynamics Equations
Directory of Open Access Journals (Sweden)
Wang Shu
2010-01-01
Full Text Available Abstract We investigate a multidimensional nonisentropic radiation hydrodynamics model. We study the local existence and the convergence of the nonisentropic radiation hydrodynamics equations via the non-relativistic limit. The local existence of smooth solutions to both systems is obtained. For well-prepared initial data, the convergence of the limit is rigorously justified by an analysis of asymptotic expansion, an energy method, and an iterative scheme. We also establish uniform a priori estimates with respect to .
Two component relativistic acceleration and polarized radiation of the parsec-scale AGN jet
Porth, Oliver
2011-06-01
We perform axisymmetric simulations of two-component jet acceleration using the special relativistic MHD code PLUTO (Mignone et al., 2007). The inner, thermally driven component constitutes a dilute relativistic plasma originating in a high enthalpy central corona. The second component is a Poynting-dominated wind driven by a global current system. Once a near-stationary state is reached, we solve the polarized Synchrotron radiation transport incorporating self-absorption and (internal) Faraday rotation. With this approach we obtain high-resolution radio maps and spectra that can help in the interpretation of observational data from nearby active galactic nuclei by predicting spine-sheath polarization structures and Faraday rotation gradients.
Classifying initial conditions of long GRBs modeled with relativistic radiation hydrodynamics
Rivera-Paleo, F. J.; López Núñez, C. E.; Guzmán, F. S.; González, J. A.
2017-06-01
We present a method to classify initial conditions of a long gamma ray bursts model sourced by a single relativistic shock. It is based on the use of artificial neural networks (ANNs) that are trained with light curves (LC) generated with radiation relativistic hydrodynamics simulations. The model we use consists in a single shock with a highly relativistic injected beam into a stratified surrounding medium with profile 1 /r2. In the process we only consider the bremsstrahlung radiation and Thomson scattering process. The initial conditions we use to train the ANN are three: the rest mass density, Lorentz factor and radiation energy density of the beam that produces the relativistic shock, together with the LC generated during the process. The classification selects the location of a box in the 3d parameter space that better fits a given LC, and in order to decrease the uncertainty of the parameters this box is refined and the classification selects a new box of smaller size.
Tang, C. L.; Wang, Y. X.; Ni, B.; Zhang, J.-C.; Reeves, G. D.; Su, Z. P.; Baker, D. N.; Spence, H. E.; Funsten, H. O.; Blake, J. B.
2017-05-01
Using the particle data measured by Van Allen Probe A from October 2012 to March 2016, we investigate in detail the radiation belt seed population and its association with the relativistic electron dynamics during 74 geomagnetic storms. The period of the storm recovery phase was limited to 72 h. The statistical study shows that geomagnetic storms and substorms play important roles in the radiation belt seed population (336 keV electrons) dynamics. Based on the flux changes of 1 MeV electrons before and after the storm peak, these storm events are divided into two groups of "large flux enhancement" and "small flux enhancement." For large flux enhancement storm events, the correlation coefficients between the peak flux location of the seed population and those of relativistic electrons (592 keV, 1 MeV, 1.8 MeV, and 2.1 MeV) during the storm recovery phase decrease with electron kinetic energy, being 0.92, 0.68, 0.49, and 0.39, respectively. The correlation coefficients between the peak flux of the seed population and those of relativistic electrons are 0.92, 0.81, 0.75, and 0.73. For small flux enhancement storm events, the correlation coefficients between the peak flux location of the seed population and those of relativistic electrons are relatively smaller, while the peak flux of the seed population is well correlated with those of relativistic electrons (correlation coefficients >0.84). It is suggested that during geomagnetic storms there is a good correlation between the seed population and ≤1 MeV electrons and the seed population is important to the relativistic electron dynamics.
Turner, D. L.; O'Brien, T. P.; Fennell, J. F.; Claudepierre, S. G.; Blake, J. B.; Jaynes, A. N.; Baker, D. N.; Kanekal, S.; Gkioulidou, M.; Henderson, M. G.; Reeves, G. D.
2017-01-01
Using observations from NASA's Van Allen Probes, we study the role of sudden particle enhancements at low L shells (SPELLS) as a source of inner radiation belt electrons. SPELLS events are characterized by electron intensity enhancements of approximately an order of magnitude or more in less than 1 day at L belt electrons under quiet/average conditions. During SPELLS events, the evolution of electron distributions reveals an enhancement of phase space density that can exceed 3 orders of magnitude in the slot region and continues into the inner radiation belt, which is evidence that these events are an important—and potentially dominant—source of inner belt electrons. Electron fluxes from September 2012 through February 2016 reveal that SPELLS occur frequently ( 2.5/month at 200 keV), but the number of observed events decreases exponentially with increasing electron energy for ≥100 keV. After SPELLS events, the slot region reforms due to slow energy-dependent decay over several day time scales, consistent with losses due to interactions with plasmaspheric hiss. Combined, these results indicate that the peaked phase space density distributions in the inner electron radiation belt result from an "on/off," geomagnetic-activity-dependent source from higher radial distances.
Study of the source term of radiation of the CDTN GE-PET trace 8 cyclotron with the MCNPX code
Energy Technology Data Exchange (ETDEWEB)
Benavente C, J. A.; Lacerda, M. A. S.; Fonseca, T. C. F.; Da Silva, T. A. [Centro de Desenvolvimento da Tecnologia Nuclear / CNEN, Av. Pte. Antonio Carlos 6627, 31270-901 Belo Horizonte, Minas Gerais (Brazil); Vega C, H. R., E-mail: jhonnybenavente@gmail.com [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas, Zac. (Mexico)
2015-10-15
Full text: The knowledge of the neutron spectra in a PET cyclotron is important for the optimization of radiation protection of the workers and individuals of the public. The main objective of this work is to study the source term of radiation of the GE-PET trace 8 cyclotron of the Development Center of Nuclear Technology (CDTN/CNEN) using computer simulation by the Monte Carlo method. The MCNPX version 2.7 code was used to calculate the flux of neutrons produced from the interaction of the primary proton beam with the target body and other cyclotron components, during 18F production. The estimate of the source term and the corresponding radiation field was performed from the bombardment of a H{sub 2}{sup 18}O target with protons of 75 μA current and 16.5 MeV of energy. The values of the simulated fluxes were compared with those reported by the accelerator manufacturer (GE Health care Company). Results showed that the fluxes estimated with the MCNPX codes were about 70% lower than the reported by the manufacturer. The mean energies of the neutrons were also different of that reported by GE Health Care. It is recommended to investigate other cross sections data and the use of physical models of the code itself for a complete characterization of the source term of radiation. (Author)
Influence of ions on relativistic double layers radiation in astrophysical plasmas
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AM Ahadi
2009-12-01
Full Text Available As double layers (DLs are one of the most important acceleration mechanisms in space as well as in laboratory plasmas, they are studied from different points of view. In this paper, the emitted power and energy radiated from charged particles, accelerated in relativistic cosmic DLs are investigated. The effect of the presence of additional ions in a multi-species plasma, as a real example of astrophysical plasma, is also investigated. Considering the acceleration role of DLs, radiations from accelerated charged particles could be seen as a loss mechanism. These radiations are influenced directly by the additional ion species as well as their relative densities.
Blazhevich, S. V.; Noskov, A. V.
2008-09-01
Coherent X-radiation of a relativistic electron crossing a single crystal plate with constant speed is considered in the two-wave approximation of the dynamic diffraction theory [Z. Pinsker, Dynamical Scattering of X-rays in Crystals, Springer, Berlin, 1984] in a Laue geometry. Analytical expressions describing the spectral-angular distribution of parametric X-radiation (PXR) and diffracted transition radiation (DTR) formed on a system of parallel atomic planes situated at an arbitrary angle δ to the surface of the crystal plate (asymmetric reflection) are derived. The dependences of the PXR and DTR spectral-angular density and their interference with angle δ are studied.
Loss of the relativistic and ultra-relativistic radiation belt electrons
Shprits, Yuri; Drozdov, Alexander; Kellerman, Adam; Usanova, Maria; Aseev, Nikita; Spasovevich, Maria
2017-04-01
Recent observations and modeling provided significant improvements in our understanding of the energization mechanisms for the electrons in the radiation belts. However, loss processes remain poorly understood. In this study we present analysis of the evolution of electron radial profiles of fluxes, pitch angle and energy distributions. Our modeling and observational results show that different loss mechanisms are operational at different energies. Global simulations at all energies, radial distances, and pitch angels are compared to Van Allen Probes observations of electron fluxes. VERB 3D model including various waves is capable of reproducing the dynamics of pitch angle distributions and energy spectra, demonstrating which loss mechanisms dominate at different energies. Analysis of the profiles of phase space density provides additional confirmation for our conclusion and presents a novel technique that identifies the region of intense local loss due to EMIC wave scattering.
Fine features of parametric X-ray radiation by relativistic electrons and ions
Korotchenko, K. B.; Eikhorn, Yu. L.; Dabagov, S. B.
2017-11-01
In present work within the frame of dynamic theory for parametric X-ray radiation in two-beam approximation we have presented detailed studies on parametric radiation emitted by relativistic both electrons and ions at channeling in crystals that is highly requested at planned experiments. The analysis done has shown that the intensity of radiation at relativistic electron channeling in Si (110) with respect to the conventional parametric radiation intensity has up to 5% uncertainty, while the error of approximate formulas for calculating parametric X-ray radiation maxima does not exceed 1.2%. We have demonstrated that simple expressions for the Fourier components of Si crystal susceptibility χ0 and χgσ could be reduced, as well as the temperature dependence for radiation maxima in Si crystal (diffraction plane (110)) within Debye model. Moreover, for any types of channeled ions it is shown that the parametric X-ray radiation intensity is proportional to z 2 - b (Z , z) / z with the function b (Z , z) depending on the screening parameter and the ion charge number z = Z -Ze.
Arakelyan, S. A.; Grigoryan, G. V.; Grigoryan, R. P.
1999-01-01
Lienard-Wiechert potentials of the relativistic spinning particle with anomalous magnetic moment in pseudoclassical theory are constructed. General expressions for the Lienard-Wiechert potentials are used for investigation of some specific cases of the motion of the spinning particle. In particular the spin dependence of the intensity of the synchrotron radiation of the transversely polarized particle performing uniform circular motion is considered. When the movement of the particle in exter...
LaRoque, Benjamin Hines
The Project 8 collaboration is taking a phased approach to developing an experimental search for the absolute neutrino mass scale, based on a novel technique, Cyclotron Radiation Emission Spectroscopy. The first phase was a demonstration of this new spectroscopy technique using a well understood source of narrow conversion electron lines, 83mKr, as a proof of principle. Results from the first successful operation of the detector are presented, demonstrating the viability of the approach. The strong conversion electron lines near 17.8, 30.4, and 32 keV were observed with full width at half maximum between 140 eV and 15 eV depending on the choice of trapping configuration used. Various upgrades were made to the detector prior to its being operated with the specific goal of determining a performance baseline for planning future phases. These included alternative trapping configurations, with which the observed full width at half maximum has been improved to 3.6 eV. Evaluation of the event reconstruction and data quality are presented based on this data collection period. Areas where improvements will be required for phase II, when the approach will be used for the first time to measure a electrons from a continuous spectrum, are identified.
Non-relativistic limit in a model of radiative flow
Czech Academy of Sciences Publication Activity Database
Nečasová, Šárka; Ducomet, B.
2015-01-01
Roč. 35, č. 2 (2015), s. 117-137 ISSN 0174-4747 R&D Projects: GA ČR GA13-00522S Institutional support: RVO:67985840 Keywords : radiation hydrodynamics * Navier-Stokes-Fourier system * weak solution Subject RIV: BA - General Mathematics http://www.degruyter.com/view/j/anly.2015.35.issue-2/anly-2012-1295/anly-2012-1295. xml
Radiation from accelerated particles in relativistic jets with shocks, shear-flow, and reconnection
Directory of Open Access Journals (Sweden)
Nishikawa K.-I.
2013-12-01
Full Text Available We have investigated particle acceleration and shock structure associated with an unmagnetized relativistic jet propagating into an unmagnetized plasma for electron-positron and electron-ion plasmas. Strong magnetic fields generated in the trailing jet shock lead to transverse deflection and acceleration of the electrons. We have self-consistently calculated the radiation from the electrons accelerated in the turbulent magnetic fields for different jet Lorentz factors. We find that the synthetic spectra depend on the bulk Lorentz factor of the jet, the jet temperature, and the strength of the magnetic fields generated in the shock. We have investigated the generation of magnetic fields associated with velocity shear between an unmagnetized relativistic (core jet and an unmagnetized sheath plasma. We discuss particle acceleration in collimation shocks for AGN jets formed by relativistic MHD simulations. Our calculated spectra should lead to a better understanding of the complex time evolution and/or spectral structure from gamma-ray bursts, relativistic jets, and supernova remnants.
Ishii, Ayako; Ohnishi, Naofumi; Nagakura, Hiroki; Ito, Hirotaka; Yamada, Shoichi
2017-11-01
We developed a three-dimensional radiative transfer code for an ultra-relativistic background flow-field by using the Monte Carlo (MC) method in the context of gamma-ray burst (GRB) emission. For obtaining reliable simulation results in the coupled computation of MC radiation transport with relativistic hydrodynamics which can reproduce GRB emission, we validated radiative transfer computation in the ultra-relativistic regime and assessed the appropriate simulation conditions. The radiative transfer code was validated through two test calculations: (1) computing in different inertial frames and (2) computing in flow-fields with discontinuous and smeared shock fronts. The simulation results of the angular distribution and spectrum were compared among three different inertial frames and in good agreement with each other. If the time duration for updating the flow-field was sufficiently small to resolve a mean free path of a photon into ten steps, the results were thoroughly converged. The spectrum computed in the flow-field with a discontinuous shock front obeyed a power-law in frequency whose index was positive in the range from 1 to 10 MeV. The number of photons in the high-energy side decreased with the smeared shock front because the photons were less scattered immediately behind the shock wave due to the small electron number density. The large optical depth near the shock front was needed for obtaining high-energy photons through bulk Compton scattering. Even one-dimensional structure of the shock wave could affect the results of radiation transport computation. Although we examined the effect of the shock structure on the emitted spectrum with a large number of cells, it is hard to employ so many computational cells per dimension in multi-dimensional simulations. Therefore, a further investigation with a smaller number of cells is required for obtaining realistic high-energy photons with multi-dimensional computations.
Liu, Si; Yan, Qi; Yang, Chang; Zhou, Qinghua; He, Zhaoguo; He, Yihua; Gao, Zhonglei; Xiao, Fuliang
2018-02-01
Previous studies have revealed a typical picture that seed electrons are transported inward under the drive of radial diffusion and then accelerated via chorus to relativistic energies. Here we show a potentially different process during the 2-3 October 2013 storm when Van Allen Probes observed extremely rapid (by about 50 times in 2 h) flux enhancements of relativistic (1.8-3.4 MeV) electrons but without distinct chorus at lower L-shells. Meanwhile, Time History of Events and Macroscale Interactions during Substorms satellites simultaneously measured enhanced chorus and fluxes of energetic (˜100-300 keV) seed electrons at higher L-shells. Numerical calculations show that chorus can efficiently accelerate seed electrons at L ˜ 8.3. Then radial diffusion further increased the phase space density of relativistic electrons throughout the outer radiation belts, with a remarkable agreement with the observation in magnitude and timescale. The current results provide a different physical scenario on the interplay between radial diffusion and local acceleration in outer radiation belt.
Energy Technology Data Exchange (ETDEWEB)
De Colle, Fabio; Ramirez-Ruiz, Enrico [Astronomy and Astrophysics Department, University of California, Santa Cruz, CA 95064 (United States); Granot, Jonathan [Racah Institute of Physics, Hebrew University, Jerusalem 91904 (Israel); Lopez-Camara, Diego, E-mail: fabio@ucolick.org [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, Ap. 70-543, 04510 D.F. (Mexico)
2012-02-20
We report on the development of Mezcal-SRHD, a new adaptive mesh refinement, special relativistic hydrodynamics (SRHD) code, developed with the aim of studying the highly relativistic flows in gamma-ray burst sources. The SRHD equations are solved using finite-volume conservative solvers, with second-order interpolation in space and time. The correct implementation of the algorithms is verified by one-dimensional (1D) and multi-dimensional tests. The code is then applied to study the propagation of 1D spherical impulsive blast waves expanding in a stratified medium with {rho}{proportional_to}r{sup -k}, bridging between the relativistic and Newtonian phases (which are described by the Blandford-McKee and Sedov-Taylor self-similar solutions, respectively), as well as to a two-dimensional (2D) cylindrically symmetric impulsive jet propagating in a constant density medium. It is shown that the deceleration to nonrelativistic speeds in one dimension occurs on scales significantly larger than the Sedov length. This transition is further delayed with respect to the Sedov length as the degree of stratification of the ambient medium is increased. This result, together with the scaling of position, Lorentz factor, and the shock velocity as a function of time and shock radius, is explained here using a simple analytical model based on energy conservation. The method used for calculating the afterglow radiation by post-processing the results of the simulations is described in detail. The light curves computed using the results of 1D numerical simulations during the relativistic stage correctly reproduce those calculated assuming the self-similar Blandford-McKee solution for the evolution of the flow. The jet dynamics from our 2D simulations and the resulting afterglow light curves, including the jet break, are in good agreement with those presented in previous works. Finally, we show how the details of the dynamics critically depend on properly resolving the structure of the
De Colle, Fabio; Granot, Jonathan; López-Cámara, Diego; Ramirez-Ruiz, Enrico
2012-02-01
We report on the development of Mezcal-SRHD, a new adaptive mesh refinement, special relativistic hydrodynamics (SRHD) code, developed with the aim of studying the highly relativistic flows in gamma-ray burst sources. The SRHD equations are solved using finite-volume conservative solvers, with second-order interpolation in space and time. The correct implementation of the algorithms is verified by one-dimensional (1D) and multi-dimensional tests. The code is then applied to study the propagation of 1D spherical impulsive blast waves expanding in a stratified medium with ρvpropr -k , bridging between the relativistic and Newtonian phases (which are described by the Blandford-McKee and Sedov-Taylor self-similar solutions, respectively), as well as to a two-dimensional (2D) cylindrically symmetric impulsive jet propagating in a constant density medium. It is shown that the deceleration to nonrelativistic speeds in one dimension occurs on scales significantly larger than the Sedov length. This transition is further delayed with respect to the Sedov length as the degree of stratification of the ambient medium is increased. This result, together with the scaling of position, Lorentz factor, and the shock velocity as a function of time and shock radius, is explained here using a simple analytical model based on energy conservation. The method used for calculating the afterglow radiation by post-processing the results of the simulations is described in detail. The light curves computed using the results of 1D numerical simulations during the relativistic stage correctly reproduce those calculated assuming the self-similar Blandford-McKee solution for the evolution of the flow. The jet dynamics from our 2D simulations and the resulting afterglow light curves, including the jet break, are in good agreement with those presented in previous works. Finally, we show how the details of the dynamics critically depend on properly resolving the structure of the relativistic flow.
Relativistic electrons of the outer radiation belt and methods of their forecast (review)
Potapov, Alexander
2017-04-01
The paper reviews studies of the dynamics of relativistic electrons in the geosynchronous region. It lists the physical processes that lead to the acceleration of electrons filling the outer radiation belt. As one of the space weather factors, high-energy electron fluxes pose a serious threat to the operation of satellite equipment in one of the most populated orbital regions. Necessity is emphasized for efforts to develop methods for forecasting the situation in this part of the magnetosphere, possible predictors are listed, and their classification is given. An example of a predictive model for forecasting relativistic electron flux with a 1-2-day lead time is proposed. Some questions of practical organization of prediction are discussed; the main objectives of short-term, medium-term, and long-term forecasts are listed.
Neutron and gamma radiation levels analysis for 18 MeV cyclotron operation at IPEN-CNEN-SP
Energy Technology Data Exchange (ETDEWEB)
Silva, Paula P.N.; Fernandes, Ivani M.; Silva, Amanda J. da; Rodrigues, Demerval L.; Romero Filho, Christovam R., E-mail: ppsilva@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)
2011-07-01
The Accelerator Cyclotron Facility provides activities that involve exposure to ionizing radiation, so it is necessary to establish a monitoring program that allows the dose control of the workers, based on the principles of the radiation protection. Besides the individual monitoring, the area monitoring is carried out aiming to evaluate the dose rates in areas that are occupied by workers during the execution of their tasks. This study aims to present the levels of neutron and gamma radiation results, obtained by monitoring the Accelerator Cyclotron Facility areas, during the Cyclone-18 operation. The study was based on data gathered from the area monitoring reports conducted by the radioprotection team in the years 2010 and 2011. To determine the dose rate, specific equipment was used. It was monitored 09 spots (from A to I), totalizing 280 and 205 measurements at each spot in the years 2010 and 2011, respectively. The 'B' spot showed the least influence for gamma and neutron radiation in both years. The spots with the highest neutron and gamma dose rates, in both years, were the 'E' and 'I' spots, respectively. With these results, we can say that the area monitoring is carrying out with its goal of preventing the doses that can be accumulated by the workers during the course of their work. (author)
The relativistic electron response in the outer radiation belt during magnetic storms
Directory of Open Access Journals (Sweden)
R. H. A. Iles
Full Text Available The relativistic electron response in the outer radiation belt during magnetic storms has been studied in relation to solar wind and geomagnetic parameters during the first six months of 1995, a period in which there were a number of recurrent fast solar wind streams. The relativistic electron population was measured by instruments on board the two microsatellites, STRV-1a and STRV-1b, which traversed the radiation belt four times per day from L ~ 1 out to L ~ 7 on highly elliptical, near-equatorial orbits. Variations in the E > 750 keV and E > 1 MeV electrons during the main phase and recovery phase of 17 magnetic storms have been compared with the solar wind speed, interplanetary magnetic field z-component, B_{z} , the solar wind dynamic pressure and Dst *. Three different types of electron responses are identified, with outcomes that strongly depend on the solar wind speed and interplanetary magnetic field orientation during the magnetic storm recovery phase. Observations also confirm that the L-shell, at which the peak enhancement in the electron count rate occurs has a dependence on Dst *.
Key words. Magnetospheric physics (energetic particles, trapped; storms and substorms – Space plasma physics (charged particle motion and accelerations
The relativistic electron response in the outer radiation belt during magnetic storms
Directory of Open Access Journals (Sweden)
R. H. A. Iles
2002-07-01
Full Text Available The relativistic electron response in the outer radiation belt during magnetic storms has been studied in relation to solar wind and geomagnetic parameters during the first six months of 1995, a period in which there were a number of recurrent fast solar wind streams. The relativistic electron population was measured by instruments on board the two microsatellites, STRV-1a and STRV-1b, which traversed the radiation belt four times per day from L ~ 1 out to L ~ 7 on highly elliptical, near-equatorial orbits. Variations in the E > 750 keV and E > 1 MeV electrons during the main phase and recovery phase of 17 magnetic storms have been compared with the solar wind speed, interplanetary magnetic field z-component, Bz , the solar wind dynamic pressure and Dst *. Three different types of electron responses are identified, with outcomes that strongly depend on the solar wind speed and interplanetary magnetic field orientation during the magnetic storm recovery phase. Observations also confirm that the L-shell, at which the peak enhancement in the electron count rate occurs has a dependence on Dst *.Key words. Magnetospheric physics (energetic particles, trapped; storms and substorms – Space plasma physics (charged particle motion and accelerations
Simulation of Relativistic Shocks and Associated Radiation from Turbulent Magnetic Fields
Nishikawa, K.-I.; Niemiec, J.; Medvedev, M.; Zhang, B.; Hardee, P.; Nordlund, A.; Frederiksen, J.; Mizuno, Y.; Sol, H.; Pohl, M.;
2011-01-01
Using our new 3-D relativistic particle-in-cell (PIC) code, we investigated long-term particle acceleration associated with a relativistic electron-positron jet propagating in an unmagnetized ambient electron-positron plasma. The simulations were performed using a much longer simulation system than our previous simulations in order to investigate the full nonlinear stage of the Weibel instability and its particle acceleration mechanism. Cold jet electrons are thermalized and ambient electrons are accelerated in the resulting shocks. Acceleration of ambient electrons leads to a maximum ambient electron density three times larger than the original value as predicted by hydrodynamic compression. Behind the bow shock, in the jet shock, strong electromagnetic fields are generated. These fields may lead to time dependent afterglow emission. In order to go beyond the standard synchrotron model used in astrophysical objects we have used PIC simulations and calculated radiation based on first principles. We calculated radiation from electrons propagating in a uniform parallel magnetic field to verify the technique. We also used the technique to calculate emission from electrons based on simulations with a small system. We obtain spectra which are consistent with those generated from electrons propagating in turbulent magnetic fields. This turbulent magnetic field is similar to the magnetic field generated at an early nonlinear stage of the Weibel instability. A fully developed shock within a larger system may generate a jitter/synchrotron spectrum.
FOREWORD: IX International Symposium on Radiation from Relativistic Electrons in Periodic Structures (RREPS-2011)
Potylitsyn, Alexander; Karataev, Pavel
2012-05-01
This volume contains papers presented at the IX International Symposium on Radiation from Relativistic Electrons in Periodic Structures (RREPS'11) which was held at Royal Holloway, University of London on September 12-16, Egham, United Kingdom. The symposium was organized jointly by Royal Holloway, University of London and Tomsk Polytechnic University, Tomsk, Russia. RREPS is a biennial series of symposia founded in September 1993 as an initiative of the Nuclear Physics Institute at Tomsk Polytechnic University. The intention was to strengthen the basic and applied research focused on radiation from relativistic electrons in condensed media, particularly from natural and artificial periodic structures, and to review the research activity in this area. Since then, the symposium has developed into a forum attracting young scientists from different areas of research and from many countries. Previous successful symposia were held at Tomsk, Russia (1993, 1995, 1997, 2003), Lake Baikal, Russia (1999), Lake Aiya, Altai, Russia (2001), Czech Technical University in Prague, Czech Republic (2007) and Zvenigorod, Moscow region, Russia (2009). As an outcome of the symposia the conference proceedings have been published in Nuclear Instruments and Methods in Physics Research, Section B (Vol. 145 No 1-2, October 1998; Vol. 173 No 1-2, January 2001; Vol. 201 No 1 January 2003; Vol. 227 No 1-2, January 2005; Vol. 266 No 17, September 2008) and Journal of Physics: Conference Series (Vol. 236, June 2010). The purpose of the present RREPS'11 symposium was to review the up-to-date situation in the area of electromagnetic radiation generated by relativistic charged particles in condensed media, and to discuss the research strategy for the near future. Nowadays, electromagnetic radiation studies cover electron energies from a few MeV up to hundreds of GeV in many laboratories throughout the world. The goal is to study the physics of the generation of various kinds of radiation and their
Hornyak, W. F.
1978-01-01
A special beam line was set up in a separate shielded experimental room to provide a low background station for gamma-ray measurements at the University of Maryland cyclotron. The transmitted beam leaving the target is gathered in by a magnetic quadrupole lens located 1.8 m further downstream and focused on a Faraday cup located on the far side of the 2.5 m thick concrete shielding wall of the experimental room. A software computer program permits timing information ot be obtained using the cyclotron beam fine structure as a time reference for the observed gamma-ray events. Measurements indicate a beam fine structure width of less than 1.2 nanoseconds repeated, for example, in the case of 140 MeV alpha particles every 90 nanoseconds. Twelve contiguous time channels of adjustable width may be set as desired with reference to the RF signal. This allows the creation of 12 separate 8192 channel analyzers.
Causal dissipation and shock profiles in the relativistic fluid dynamics of pure radiation
Freistühler, Heinrich; Temple, Blake
2014-01-01
Current theories of dissipation in the relativistic regime suffer from one of two deficits: either their dissipation is not causal or no profiles for strong shock waves exist. This paper proposes a relativistic Navier–Stokes–Fourier-type viscosity and heat conduction tensor such that the resulting second-order system of partial differential equations for the fluid dynamics of pure radiation is symmetric hyperbolic. This system has causal dissipation as well as the property that all shock waves of arbitrary strength have smooth profiles. Entropy production is positive both on gradients near those of solutions to the dissipation-free equations and on gradients of shock profiles. This shows that the new dissipation stress tensor complies to leading order with the principles of thermodynamics. Whether higher order modifications of the ansatz are required to obtain full compatibility with the second law far from the zero-dissipation equilibrium is left to further investigations. The system has exactly three a priori free parameters χ,η,ζ, corresponding physically to heat conductivity, shear viscosity and bulk viscosity. If the bulk viscosity is zero (as is stated in the literature) and the total stress–energy tensor is trace free, the entire viscosity and heat conduction tensor is determined to within a constant factor. PMID:24910526
Wu, C. S.; Lin, C. S.; Wong, H. K.; Tsai, S. T.; Zhou, R. L.
1981-01-01
An investigation is presented of two cases: (1) weakly relativistic electrons with a loss-cone type distribution, and (2) electrons with a drift velocity parallel to the ambient magnetic field. Numerical computations are given for physical parameters close to those in the polar region of the earth magnetosphere and laboratory experiments, with attention to the fast extraordinary-mode radiation whose frequency is near that of the electron cyclotron frequency. The fast extraordinary mode can escape from a strong field region to the weaker field region and may therefore be measured outside the plasma. It is found that the X mode radiation can be amplified by means of a cyclotron maser effect when the electrons have a loss-cone distribution, and it is concluded that, when the electron energy is sufficiently high, the X mode cutoff frequency may be lower than the cyclotron frequency.
Relativistic electron precipitation enhancements near the outer edge of the radiation belt
Nakamura, R.; Baker, N. D.; Blake, J. B.; Kanekal, S.; Klecker, B.; Hovestadt, D.
1995-01-01
Characteristics of relativistic electron precipitation bursts observed by the Heavy Ion Large Telescope (HILT) experiment onboard the Solar, Anomalous, and Magnetospheric Partical Explorer (SAMPEX) satellite were examined. Relatively narrow, persitent, latitudinal bands of precipitation with time scales of 10 to approximately 30 sec near the outer edge of the radiation belt which develop and decay with a time scale of a few hours are reported. Acceleration processes more effective than the usual radial diffusion process or scattering process would be needed to explain this strong precipitation band phenomenon. Another prominent signature is microbursts with a time scale down to a few hundred milliseconds. It is suggested that these microbursts are due to wave-particle interaction involving a relaxation-oscillator type of mechanism.
Lu, Wenbin; Krolik, Julian; Crumley, Patrick; Kumar, Pawan
2017-10-01
Reverberation observations yielding a lag spectrum have uncovered an Fe K α fluorescence line in the tidal disruption event (TDE) Swift J1644+57. The discovery paper used the lag spectrum to argue that the source of the X-ray continuum was located very close to the black hole (˜30 gravitational radii) and moved subrelativistically. We reanalyse the lag spectrum, pointing out that dilution effects cause it to indicate a geometric scale an order of magnitude larger than inferred by Kara et al. If the X-ray continuum is produced by a relativistic jet, as suggested by the rapid variability, high luminosity and hard spectrum, this larger scale predicts an Fe ionization state consistent with efficient K α photon production. Moreover, the momentum of the jet X-rays impinging on the surrounding accretion flow on this large scale accelerates a layer of gas to speeds ˜0.1-0.2c, consistent with the blueshifted line profile. Implications of our results on the global picture of jetted TDEs are discussed. A power-law γ/X-ray spectrum may be produced by external ultraviolet (UV)-optical photons being repetitively inverse-Compton scattered by cold electrons in the jet, although our model for the K α reverberation does not depend on the jet radiation mechanism (magnetic reconnection in a Poynting jet is still a viable mechanism). The non-relativistic wind driven by jet radiation may explain the late-time radio rebrightening in Swift J1644+57. This energy injection may also cause the thermal UV-optical emission from jetted TDEs to be systematically brighter than in non-jetted ones.
Rapid local acceleration of relativistic radiation-belt electrons by magnetospheric chorus.
Thorne, R M; Li, W; Ni, B; Ma, Q; Bortnik, J; Chen, L; Baker, D N; Spence, H E; Reeves, G D; Henderson, M G; Kletzing, C A; Kurth, W S; Hospodarsky, G B; Blake, J B; Fennell, J F; Claudepierre, S G; Kanekal, S G
2013-12-19
Recent analysis of satellite data obtained during the 9 October 2012 geomagnetic storm identified the development of peaks in electron phase space density, which are compelling evidence for local electron acceleration in the heart of the outer radiation belt, but are inconsistent with acceleration by inward radial diffusive transport. However, the precise physical mechanism responsible for the acceleration on 9 October was not identified. Previous modelling has indicated that a magnetospheric electromagnetic emission known as chorus could be a potential candidate for local electron acceleration, but a definitive resolution of the importance of chorus for radiation-belt acceleration was not possible because of limitations in the energy range and resolution of previous electron observations and the lack of a dynamic global wave model. Here we report high-resolution electron observations obtained during the 9 October storm and demonstrate, using a two-dimensional simulation performed with a recently developed time-varying data-driven model, that chorus scattering explains the temporal evolution of both the energy and angular distribution of the observed relativistic electron flux increase. Our detailed modelling demonstrates the remarkable efficiency of wave acceleration in the Earth's outer radiation belt, and the results presented have potential application to Jupiter, Saturn and other magnetized astrophysical objects.
Radiation protection and environmental management at the relativistic heavy ion collider.
Musolino, S V; Briggs, S L; Stevens, A J
2001-01-01
The Relativistic Heavy Ion Collider (RHIC) is a high energy hadron accelerator built to study basic nuclear physics. It consists of two counter-rotating beams of fully stripped gold ions that are accelerated in two rings to an energy of 100 GeV/nucleon or protons at 250 GeV/c. The beams can be stored for a period of five to ten hours and brought into collision for experiments during that time. The first major physics objective is to recreate a state of matter, the quark-gluon plasma, that has been predicted to have existed at a short time after the creation of the universe. Because there are only a few other high energy particle accelerators like RHIC in the world, the rules promulgated in the US Code of Federal Regulations under the Atomic Energy Act, State regulations, or international guidance documents do not cover prompt radiation from accelerators to govern directly the design and operation of a superconducting collider. Special design criteria for prompt radiation were developed to provide guidance tor the design of radiation shielding. Environmental Management at RHIC is accomplished through the ISO 14001 Environmental Management System. The applicability, benefits, and implementation of ISO 14001 within the framework of a large research accelerator complex are discussed in the paper.
Pokhotelov, D.; Rae, I. J.; Murphy, K. R.; Mann, I. R.
2016-12-01
Electromagnetic ultralow-frequency (ULF) waves are known to play a substantial role in radial transport, acceleration, and loss of relativistic particles trapped in the Earth's outer radiation belt. Using in situ observations by multiple spacecraft operating in the vicinity of outer radiation belts, we analyze the temporal and spatial behavior of ULF waves throughout the geomagnetic storm of 8-9 October 2012 and compare with the dynamics of relativistic electron fluxes on board the twin Van Allen Probes spacecraft. The analysis shows that the relativistic electron fluxes reduce from their prestorm levels during the first phase of the storm and rapidly increase during the second phase of the storm. We demonstrate that the behavior of ULF wave power changes throughout the storm, from ULF oscillations being a mixture of compressional and shear magnetic components during the first phase of the storm to ULF oscillations being dominated by transverse (shear) components during the second phase. We analyze the parameters of ULF-driven radial diffusion throughout the storm and compare the observed diffusion coefficients with their statistical averages. We demonstrate that the observed diffusion coefficients are strong enough to impact the redistribution of relativistic electron fluxes from and to the outer boundary of radiation belts and the diffusion might influence the effects of any local electron acceleration by transporting fluxes inward or outward according to phase space density gradients.
Modeling the Proton Radiation Belt With Van Allen Probes Relativistic Electron-Proton Telescope Data
Selesnick, R. S.; Baker, D. N.; Kanekal, S. G.; Hoxie, V. C.; Li, X.
2018-01-01
An empirical model of the proton radiation belt is constructed from data taken during 2013-2017 by the Relativistic Electron-Proton Telescopes on the Van Allen Probes satellites. The model intensity is a function of time, kinetic energy in the range 18-600 MeV, equatorial pitch angle, and L shell of proton guiding centers. Data are selected, on the basis of energy deposits in each of the nine silicon detectors, to reduce background caused by hard proton energy spectra at low L. Instrument response functions are computed by Monte Carlo integration, using simulated proton paths through a simplified structural model, to account for energy loss in shielding material for protons outside the nominal field of view. Overlap of energy channels, their wide angular response, and changing satellite orientation require the model dependencies on all three independent variables be determined simultaneously. This is done by least squares minimization with a customized steepest descent algorithm. Model uncertainty accounts for statistical data error and systematic error in the simulated instrument response. A proton energy spectrum is also computed from data taken during the 8 January 2014 solar event, to illustrate methods for the simpler case of an isotropic and homogeneous model distribution. Radiation belt and solar proton results are compared to intensities computed with a simplified, on-axis response that can provide a good approximation under limited circumstances.
Nishikawa, Ken-Ichi; Niemiec, J.; Medvedev, M.; Zhang, B.; Hardee, P.; Mizuno, Y.; Nordlund, A.; Frederiksen, J.; Sol, H.; Pohl, M.;
2010-01-01
Plasma instabilities excited in collisionless shocks are responsible for particle acceleration. We have investigated the particle acceleration and shock structure associated with an unmagnetized relativistic electron-positron jet propagating into an unmagnetized electron-positron plasma. Cold jet electrons are thermalized and slowed while the ambient electrons are swept up to create a partially developed hydrodynamic-like shock structure. In the leading shock, electron density increases by a factor of about 3.5 in the simulation frame. Strong electromagnetic fields are generated in the trailing shock and provide an emission site. This simulation corresponds to a case for gamma-ray burst afterglows. We will simulate colliding shells as an internal shock model for prompt emission. Turbulent magnetic fields generated by a slower shell will be collided by a faster shell. These magnetic fields contribute to the electron s transverse deflection behind the shock. We calculate the radiation from deflected electrons in the turbulent magnetic fields. The properties of this radiation may be important to understanding the complex time evolution and/or spectral structure in gamma-ray bursts
Observation of coherently enhanced tunable narrow-band terahertz transition radiation from a relativistic sub-picosecond electron bunch train
Energy Technology Data Exchange (ETDEWEB)
Piot, P. [Northern Illinois Univ., DeKalb, IL (United States); Fermi National Accelerator Laboratory (FNAL), Batavia, IL (United States); Sun, Y. -E [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Maxwell, T. J. [Northern Illinois Univ., DeKalb, IL (United States); Fermi National Accelerator Laboratory (FNAL), Batavia, IL (United States); Ruan, J. [Fermi National Accelerator Laboratory (FNAL), Batavia, IL (United States); Lumpkin, A. H. [Fermi National Accelerator Laboratory (FNAL), Batavia, IL (United States); Rihaoui, M. M. [Northern Illinois Univ., DeKalb, IL (United States); Thurman-Keup, R. [Fermi National Accelerator Laboratory (FNAL), Batavia, IL (United States)
2011-06-27
We experimentally demonstrate the production of narrow-band (δf/f ~ =20% at f ~ = 0.5 THz) THz transition radiation with tunable frequency over [0.37, 0.86] THz. The radiation is produced as a train of sub-picosecond relativistic electron bunches transits at the vacuum-aluminum interface of an aluminum converter screen. In addition, we show a possible application of modulated beams to extend the dynamical range of a popular bunch length diagnostic technique based on the spectral analysis of coherent radiation.
Meredith, Nigel P.; Horne, Richard B.; Sandberg, Ingmar; Papadimitriou, Constantinos; Evans, Hugh D. R.
2017-07-01
Relativistic electrons (E > 500 keV) cause internal charging and are an important space weather hazard. To assess the vulnerability of the satellite fleet to these so-called "killer" electrons, it is essential to estimate reasonable worst cases, and, in particular, to estimate the flux levels that may be reached once in 10 and once in 100 years. In this study we perform an extreme value analysis of the relativistic electron fluxes in the Earth's outer radiation belt as a function of energy and L∗. We use data from the Radiation Environment Monitor (IREM) on board the International Gamma Ray Astrophysical Laboratory (INTEGRAL) spacecraft from 17 October 2002 to 31 December 2016. The 1 in 10 year flux at L∗=4.5, representative of equatorial medium Earth orbit, decreases with increasing energy ranging from 1.36 × 107 cm-2 s-1 sr-1 MeV-1 at E = 0.69 MeV to 5.34 × 105 cm-2 s-1 sr-1 MeV-1 at E = 2.05 MeV. The 1 in 100 year flux at L∗=4.5 is generally a factor of 1.1 to 1.2 larger than the corresponding 1 in 10 year flux. The 1 in 10 year flux at L∗=6.0, representative of geosynchronous orbit, decreases with increasing energy ranging from 4.35 × 106 cm-2 s-1 sr-1 MeV-1 at E = 0.69 MeV to 1.16 × 105 cm-2 s-1 sr-1 MeV-1 at E = 2.05 MeV. The 1 in 100 year flux at L∗=6.0 is generally a factor of 1.1 to 1.4 larger than the corresponding 1 in 10 year flux. The ratio of the 1 in 10 year flux at L∗=4.5 to that at L∗=6.0 increases with increasing energy ranging from 3.1 at E = 0.69 MeV to 4.6 at E = 2.05 MeV.
Interaction of a relativistic electron beam with radiation in the THz frequency range
Sung, Chieh
The ability to generate a train of microbunches that are only typically tens of femtosecond wide and are separated by a picosecond is a topic of contemporary interest in the field of free electron lasers and plasma based accelerators. Moreover the usefulness of the high gradients present in plasma accelerators will depend on the ability to obtain mono-energetic relativistic electrons. This means that in addition to being prebunched on a scale shorter than the plasma wavelength the externally injected electron beam must be phase-locked to the accelerating plasma wave structure. In this thesis we investigate two techniques, Free Electron Laser interaction (FEL) and the Inverse Free Electron Laser interaction (IFEL), by which a medium energy electron beam can be prebunched into a series of microbunches with the same periodicity as a plasma wave and is phase locked to it. Using full-scale, 3-D simulations we show in this thesis that when a relativistic electron beam and an electromagnetic wave propagate collinearly through a magnetic undulator, FEL and IFEL interactions have the capability to form electron microbunches with periodicity 300-100 mum (1-3 THz range), which contain 50% of electrons within a small fraction of the ponderomotive buckets. Such a bunched beam is suitable for injection into plasma densities in the range 1016-1017 cm-3, respectively. Microbunching using the FEL mechanism requires a narrowband THz radiation source to act as a seed whereas the IFEL mechanism requires, in addition, such a source to be high power. In this thesis the generation of THz radiation in the Neptune Laboratory by mixing of two CO2 laser lines in a non-collinearly phase matched GaAs at room temperature is described A high-power THz pulse with up to 2 MW of peak power in a 250 ps pulse was generated using a TW class CO2 laser pulse. Such high power THz radiation is needed for the IFEL approach to microbunching. We also produced a high repetition rate THz source tunable in the
Twisted Radiation by Electrons in Spiral Motion
Katoh, M; Mirian, N S; Konomi, T; Taira, Y; Kaneyasu, T; Hosaka, M; Yamamoto, N; Mochihashi, A; Takashima, Y; Kuroda, K; Miyamoto, A; Miyamoto, K; Sasaki, S
2016-01-01
We theoretically show that a single free electron in circular/spiral motion radiates an electromagnetic wave possessing helical phase structure and carrying orbital angular momentum. We experimentally demonstrate it by double-slit diffraction on radiation from relativistic electrons in spiral motion. We show that twisted photons should be created naturally by cyclotron/synchrotron radiations or Compton scatterings in various situations in astrophysics. We propose promising laboratory vortex photon sources in various wavelengths ranging from radio wave to gamma-rays.
Transverse phase space mapping of relativistic electron beams using optical transition radiation
Directory of Open Access Journals (Sweden)
G. P. Le Sage
1999-12-01
Full Text Available Optical transition radiation (OTR has proven to be a versatile and effective diagnostic for measuring the profile, divergence, and emittance of relativistic electron beams with a wide range of parameters. Diagnosis of the divergence of modern high brightness beams is especially well suited to OTR interference (OTRI techniques, where multiple dielectric or metal foils are used to generate a spatially coherent interference pattern. Theoretical analysis of measured OTR and OTRI patterns allows precise measurement of electron beam emittance characteristics. Here we describe an extension of this technique to allow mapping of divergence characteristics as a function of transverse coordinates within a measured beam. We present the first experimental analysis of the transverse phase space of an electron beam using all optical techniques. Comparing an optically masked portion of the beam to the entire beam, we measure different angular spread and average direction of the particles. Direct measurement of the phase-space ellipse tilt angle has been demonstrated using this optical masking technique.
Baker, D. N.; Blake, J. B.; Callis, L. B.; Cummings, J. R.; Hovestadt, D.; Kanekal, S.; Klecker, B.; Mewaldt, R. A.; Zwickl, R. D.
1994-01-01
High-energy electrons have been measured systematically in a low-altitude (520 x 675 km), nearly polar (inclination = 82 deg) orbit by sensitive instruments onboard the Solar, Anomalous, and Magnetospheric Particle Explorer (SAMPEX). Count rate channels with electron energy thresholds ranging from 0.4 MeV to 3.5 MeV in three different instruments have been used to examine relativistic electron variations as a function of L-shell parameter and time. A long run of essentially continuous data (July 1992 - July 1993) shows substantial acceleration of energetic electrons throughout much of the magnetosphere on rapid time scales. This acceleration appears to be due to solar wind velocity enhancements and is surprisingly large in that the radiation belt 'slot' region often is filled temporarily and electron fluxes are strongly enhanced even at very low L-values (L aprroximately 2). A superposed epoch analysis shows that electron fluxes rise rapidly for 2.5 is approximately less than L is approximately less than 5. These increases occur on a time scale of order 1-2 days and are most abrupt for L-values near 3. The temporal decay rate of the fluxes is dependent on energy and L-value and may be described by J = Ke-t/to with t(sub o) approximately equals 5-10 days. Thus, these results suggest that the Earth's magnetosphere is a cosmic electron accelerator of substantial strength and efficiency.
Monte Carlo simulations of relativistic radiation-mediated shocks - I. Photon-rich regime
Ito, Hirotaka; Levinson, Amir; Stern, Boris E.; Nagataki, Shigehiro
2018-02-01
We explore the physics of relativistic radiation-mediated shocks (RRMSs) in the regime where photon advection dominates over photon generation. For this purpose, a novel iterative method for deriving a self-consistent steady-state structure of RRMS is developed, based on a Monte Carlo code that solves the transfer of photons subject to Compton scattering and pair production/annihilation. Systematic study is performed by imposing various upstream conditions which are characterized by the following three parameters: the photon-to-baryon inertia ratio ξu*, the photon-to-baryon number ratio \\tilde{n}, and the shock Lorentz factor γu. We find that the properties of RRMSs vary considerably with these parameters. In particular, while a smooth decline in the velocity, accompanied by a gradual temperature increase is seen for ξu* ≫ 1, an efficient bulk Comptonization, that leads to a heating precursor, is found for ξu* ≲ 1. As a consequence, although particle acceleration is highly inefficient in these shocks, a broad non-thermal spectrum is produced in the latter case. The generation of high-energy photons through bulk Comptonization leads, in certain cases, to a copious production of pairs that provide the dominant opacity for Compton scattering. We also find that for certain upstream conditions a weak subshock appears within the flow. For a choice of parameters suitable to gamma-ray bursts, the radiation spectrum within the shock is found to be compatible with that of the prompt emission, suggesting that subphotospheric shocks may give rise to the observed non-thermal features despite the absence of accelerated particles.
2013-06-17
these radiation-induced oscillations do overlap the more-rapidly- varying-with-B Shubnikov–de Haas ( SdH ) oscillations; see also Refs. 17, 21, and 22. A... SdH Oscillations RIMRO FIG. 2. (Color online) Microwave (f < 300 GHz) and terahertz (f 300 GHz) radiation-induced magnetoresistance oscillations in...Shubnikov–de Haas ( SdH ) oscillations. A subset of oscillations of each type are marked on the figure. The solid vertical lines below 0.1 T marks the
Directory of Open Access Journals (Sweden)
Zargan S.
2017-03-01
Full Text Available Background: PET/CT imaging using [18F]-FDG is utilized in clinical oncology for tumor detecting, staging and responding to therapy procedures. Essential consideration must be taken for radiation staff due to high gamma radiation in PET/CT and cyclotron center. The aim of this study was to assess the staff exposure regarding whole body and organ dose and to evaluate environment dose in PET/CT and cyclotron center. Materials and Methods: 80 patients participated in this study. Thermoluminescence, electronic personal dosimeter and Geiger–Muller dosimeter were also utilized for measurement purpose. Results: The mean annual equivalent organ dose for scanning operator with regard to lens of eyes, thyroid, breast and finger according to mean±SD value, were 0.262±0.044, 0.256±0.046, 0.257±0.040 and 0.316±0.118, respectively. The maximum and minimum estimated annual whole body doses were observed for injector and the chemist group with values of (3.98±0.021 mSv/yr and (1.64±0.014 mSv/yr, respectively. The observed dose rates were 5.67 µSv/h in uptake room at the distance of 0.5 meter from the patient whereas the value 4.94 and 3.08 µSv/h were recorded close to patient’s head in PET/CT room and 3.5 meter from the reception desk. Conclusion: In this study, the injector staff and scanning operator received the first high level and second high level of radiation. This study confirmed that low levels of radiation dose were received by all radiation staff during PET/CT procedure using 18F-FDG due to efficient shielding and using trained radiation staff in PET/CT and cyclotron center of Masih Daneshvari hospital.
Zargan, S; Ghafarian, P; Shabestani Monfared, A; Sharafi, A A; Bakhshayeshkaram, M; Ay, M R
2017-03-01
PET/CT imaging using [18F]-FDG is utilized in clinical oncology for tumor detecting, staging and responding to therapy procedures. Essential consideration must be taken for radiation staff due to high gamma radiation in PET/CT and cyclotron center. The aim of this study was to assess the staff exposure regarding whole body and organ dose and to evaluate environment dose in PET/CT and cyclotron center. 80 patients participated in this study. Thermoluminescence, electronic personal dosimeter and Geiger-Muller dosimeter were also utilized for measurement purpose. The mean annual equivalent organ dose for scanning operator with regard to lens of eyes, thyroid, breast and finger according to mean±SD value, were 0.262±0.044, 0.256±0.046, 0.257±0.040 and 0.316±0.118, respectively. The maximum and minimum estimated annual whole body doses were observed for injector and the chemist group with values of (3.98±0.021) mSv/yr and (1.64±0.014) mSv/yr, respectively. The observed dose rates were 5.67 µSv/h in uptake room at the distance of 0.5 meter from the patient whereas the value 4.94 and 3.08 µSv/h were recorded close to patient's head in PET/CT room and 3.5 meter from the reception desk. In this study, the injector staff and scanning operator received the first high level and second high level of radiation. This study confirmed that low levels of radiation dose were received by all radiation staff during PET/CT procedure using 18F-FDG due to efficient shielding and using trained radiation staff in PET/CT and cyclotron center of Masih Daneshvari hospital.
Improved system for perpendicular electron-cyclotron emission measurements on TMX-Upgrade
Energy Technology Data Exchange (ETDEWEB)
Lasnier, C.J.; Ellis, R.F.; James, R.A.
1986-03-07
Perpendicular electron-cyclotron emission (PECE) is used on TMX-U to diagnose thermal-barrier hot electrons (T/sub H/ approx. 100 to 400 keV); yielding the time history of the temperature of these relativistic electrons. We describe an improved quasi-optical viewing system for these measurements that uses high sensitivity superheterodyne receivers at fixed frequencies of 60, 98, 130, and 196 GHz. The improved viewing and transport system consists of an off-axis ellipsoidal mirror that images the plasma onto a V-band conical collection horn, an overmoded circular waveguide (7/8'' diam) that transports the radiation outside the vacuum vessel where the polarization is selected, and a high absorptivity Macor beam dump to prevent internal wall reflections from entering the viewing system. A relativistic code is used to calculate optically thin PECE signals from relativistic electrons for various energy and pitch angle distributions. 4 refs., 4 figs.
Liu, S.; Xiao, F.; Yang, C.; Zhou, Q.; He, Y.
2016-12-01
The possible acceleration mechanisms of relativistic electron fluxes in Earth's outer radiation belt are basically categorized into two groups: radial diffusion and in-situ acceleration. A physical understanding and modeling of the radiation belt dynamic require an investigation of the electron phase space density (PSD) to provide a delicate picture of the mechanisms. Here, we study the time evolution of relativistic electron PSD during two events. During 23 to 24 September, 2014, with minimum Dst=-27 nT and maximum Kp 4, relativistic (2.1 -3.4 MeV) electron fluxes and chorus waves were substantially enhanced at L=4.5-6 by the Van Allen Probes. Pronounced peaks in PSD radial profiles occurred at L*=4.9-5.2, suggesting a local acceleration process as the primary mechanism. Numerical calculation shows that bounce-averaged momentum diffusion coefficient from chorus wave approaches 10-5 s-1 at large pitch angle for 2 MeV electrons. Meanwhile, electromagnetic and electrostatic radial diffusion coefficients (DMLL and DELL) are smaller than approximately by 3-20 times and 25-100 times respectively. This indicates that chorus-electron interaction dominates the PSD evolution over the radial diffusion in this event. During 1 to 3 October, 2013, with minimum Dst=-67 nT and maximum Kp 8, relativistic electron fluxes increased by 1-2 orders at L=4.8-5.8, while chorus waves are not directly observed. The PSD radial profiles monotonically increases with L*. We find that DMLL and DELL can approach 10-4 s-1 and 10-5 s-1 respectively. Using inferred chorus intensity 50 pT, we obtain the momentum diffusion coefficient as about 10-6 s-1. The above calculations and observations indicated that the radial diffusion tends to be the dominant process for the PSD enhancement. The present results provide a direct support and reveal a typical picture for the previous statistical characteristics of radial PSD evolution related to different internal, magnetospheric processes. It further
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
Blazhevich, S. V.; Zagorodnyuk, R. A.; Noskov, A. V.
2015-07-01
In the present work a theory of coherent radiation of a relativistic electron moving at a constant speed in a combined target, consisting of several amorphous matter layers and a monocrystalline layer is built. The expressions describing the amplitudes of diffracted transition radiation (DTR) and parametric X-ray radiation (PXR) are derived within the framework of two-wave approach of the dynamic diffraction theory. The cases of one and two amorphous matter layers in the structure were considered. Also the extreme case, when vacuum is considered as the second amorphous layer in the structure, is investigated. The expressions obtained describe a spectral-angular distribution of DTR, PXR and their interference in such a structure. The X-ray wave generation and propagation processes in crystalline layer are considered in Laue scattering geometry for the general case of asymmetric reflection.
Energy Technology Data Exchange (ETDEWEB)
Blazhevich, S.V., E-mail: blazh@bsu.edu.ru; Zagorodnyuk, R.A.; Noskov, A.V.
2015-07-15
In the present work a theory of coherent radiation of a relativistic electron moving at a constant speed in a combined target, consisting of several amorphous matter layers and a monocrystalline layer is built. The expressions describing the amplitudes of diffracted transition radiation (DTR) and parametric X-ray radiation (PXR) are derived within the framework of two-wave approach of the dynamic diffraction theory. The cases of one and two amorphous matter layers in the structure were considered. Also the extreme case, when vacuum is considered as the second amorphous layer in the structure, is investigated. The expressions obtained describe a spectral-angular distribution of DTR, PXR and their interference in such a structure. The X-ray wave generation and propagation processes in crystalline layer are considered in Laue scattering geometry for the general case of asymmetric reflection.
Khorshidi, Abdollah; Pazirandeh, Ali; Tenreiro, Claudio; Kadi, Yacine
2014-01-01
In this study, the transmutation adiabatic resonance crossing (TARC) concept was estimated in Mo-99 radioisotope production via radiative capture reaction in two designs. The TARC method was composed of moderating neutrons in lead or a composition of lead and water. Additionally, the target was surrounded by a moderator assembly and a graphite reflector district. Produced neutrons were investigated by (p,xn) interactions with 30 MeV and 300 mu A proton beam on tungsten, beryllium, and tantalum targets. The Mo-99 production yield was related to the moderator property, cross section, and sample positioning inside the distinct region of neutron storage as must be proper to achieve gains. Gathered thermal flux of neutrons can contribute to molybdenum isotope production. Moreover, the sample positioning to gain higher production yield was dependent on a greater flux in the length of thermal neutrons and region materials inside the moderator or reflector. When the sample radial distance from Be was 38 cm inside the...
Moya, Pablo S.; Pinto, Víctor A.; Sibeck, David G.; Kanekal, Shrikanth G.; Baker, Daniel N.
2017-11-01
Using Van Allen Probes Energetic Particle, Composition, and Thermal Plasma-Relativistic Electron-Proton Telescope (ECT-REPT) observations, we performed a statistical study on the effect of geomagnetic storms on relativistic electrons fluxes in the outer radiation belt for 78 storms between September 2012 and June 2016. We found that the probability of enhancement, depletion, and no change in flux values depends strongly on L and energy. Enhancement events are more common for ˜2 MeV electrons at L ˜ 5, and the number of enhancement events decreases with increasing energy at any given L shell. However, considering the percentage of occurrence of each kind of event, enhancements are more probable at higher energies, and the probability of enhancement tends to increases with increasing L shell. Depletion are more probable for 4-5 MeV electrons at the heart of the outer radiation belt, and no-change events are more frequent at L 4.5 the probability of enhancement, depletion, or no-change response presents little variation for all energies. Because these probabilities remain relatively constant as a function of radial distance in the outer radiation belt, measurements obtained at geosynchronous orbit may be used as a proxy to monitor E≥1.8 MeV electrons in the outer belt.
Energy Technology Data Exchange (ETDEWEB)
Blazhevich, S. V.; Noskov, A. V., E-mail: noskovbupk@mail.ru [Belgorod State University (Russian Federation)
2016-10-15
We consider diffracted transition radiation (DTR) emitted by high-energy relativistic electrons crossing a thin single-crystal wafer in the Laue geometry. The expression describing the DTR angular density is derived for the case where the electron path length in the target is much smaller than the X-ray wave extinction length in the crystal and the kinematic nature of this expression is demonstrated. It is shown that the DTR angular density in a thin target is proportional to the target thickness.
Numerical Relativistic Quantum Optics
2013-11-08
m is a signed cyclotron frequency, nr is the radial quantum number and ` is the orbital quantum number. The principle quantum number is n ≡ nr...Gordon equation is accomplished via domain decomposition, where each GPGPU advances the solution in a given domain, and MPI is used for commu...other points to the corresponding location in the transfer buffer. Once the ghost cells have been updated, the GPGPU can advance the relativistic wave
Relativistic methods for chemists
Barysz, Maria
2010-01-01
"Relativistic Methods for Chemists", written by a highly qualified team of authors, is targeted at both experimentalists and theoreticians interested in the area of relativistic effects in atomic and molecular systems and processes and in their consequences for the interpretation of the heavy element's chemistry. The theoretical part of the book focuses on the relativistic methods for molecular calculations discussing relativistic two-component theory, density functional theory, pseudopotentials and correlations. The experimentally oriented chapters describe the use of relativistic methods in different applications focusing on the design of new materials based on heavy element compounds, the role of the spin-orbit coupling in photochemistry and photobiology, and chirality and its relations to relativistic description of matter and radiation. This book is written at an intermediate level in order to appeal to a broader audience than just experts working in the field of relativistic theory.
BEST medical radioisotope production cyclotrons
Energy Technology Data Exchange (ETDEWEB)
Sabaiduc, Vasile; Milton, Bruce; Suthanthiran, Krishnan; Johnson, Richard R. [Best Cyclotron Systems Inc., 7-8765 Ash Street, Vancouver, British Columbia, V6P 6T3 (Canada); Gelbart, W. Z. [Advanced System Designs Inc., 5295 Bear Bay Road, Garden Bay, BC, V0N 1S1 (Canada)
2013-04-19
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 {mu}A to 1000 {mu}A, depending on the cyclotron energy and application.
Non-adiabatic radiative collapse of a relativistic star under different ...
Indian Academy of Sciences (India)
used this space-time metric and examined various features of the evolution of the collapse of a shear-free homogeneous and isotropic configuration of matter. Pinheiro and Chan. [4,5] analysed the collapse of a matter distribution of uniform matter density with shear. We have examined the collapse of a relativistic star with ...
Vinas, A. F.; Moya, P. S.; Pinto, V. A.; Sibeck, D. G.; Kanekal, S.; Kletzing, C.
2015-12-01
The response of the inner magnetosphere to different geomagnetic storm and solar wind conditions is still not fully understood. For example, electron fluxes in the outer radiation belt can be enhanced or depleted depending on the energy of the particles, and the phase or driver of the storm. In addition, the time scale of the process can vary from minutes to several days. Wave-particle interactions (such as stochastic diffusion or resonant acceleration) are believed to play an important role regulating the dynamics of the particles. However, despite decades of intense theoretical and observational studies, a definitive framework for the wave-particle interactions and the resulting effects in the magnetospheric dynamics remains an open problem. To progress towards a better understanding of the inner magnetosphere dynamics, we need a complete characterization of the electromagnetic fluctuations during storms. Here, using Van Allen Probe magnetic field and relativistic electron observations, we present an statistical study of the relationship between ULF wave power and relativistic electron fluxes in the outer radiation belt during several geomagnetic storms between 2012 and 2015, depending on local time, geocentric distance and storm phase.
Source and seed populations for relativistic electrons: Their roles in radiation belt changes
Jaynes, AN; Baker, DN; Singer, HJ; Rodriguez, JV; Loto'aniu, TM; Ali, AF; Elkington, SR; Li, X; Kanekal, SG; Fennell, JF; Li, W; Thorne, RM; Kletzing, CA; Spence, HE; Reeves, GD
2015-01-01
©2015. American Geophysical Union. All Rights Reserved. Strong enhancements of outer Van Allen belt electrons have been shown to have a clear dependence on solar wind speed and on the duration of southward interplanetary magnetic field. However, individual case study analyses also have demonstrated that many geomagnetic storms produce little in the way of outer belt enhancements and, in fact, may produce substantial losses of relativistic electrons. In this study, focused upon a key period in...
Source and seed populations for relativistic electrons: Their roles in radiation belt changes
Jaynes, AN; Baker, DN; Singer, HJ; Rodriguez, JV; Rodriguez, JV; Loto'aniu, TM; Loto'aniu, TM; Ali, AF; Elkington, SR; Li, X; Kanekal, SG; Fennell, JF; Li, W; Thorne, RM; Kletzing, CA
2015-01-01
© 2015. American Geophysical Union. All Rights Reserved. Strong enhancements of outer Van Allen belt electrons have been shown to have a clear dependence on solar wind speed and on the duration of southward interplanetary magnetic field. However, individual case study analyses also have demonstrated that many geomagnetic storms produce little in the way of outer belt enhancements and, in fact, may produce substantial losses of relativistic electrons. In this study, focused upon a key period i...
Precipitation of radiation belt electrons by EMIC waves, observed from ground and space
Energy Technology Data Exchange (ETDEWEB)
Jordanova, Vania K [Los Alamos National Laboratory; Miyoski, Y [NAGOYA UNIV; Sakaguchi, K [NAGOYA UNIV; Shiokawa, K [NAGOYA UNIV; Evans, D S [NOAA, BOULDER; Albert, Jay [AFRL; Connors, M [UNIV OF ATHABASCA
2008-01-01
We show evidence that left-hand polarised electromagnetic ion cyclotron (EMIC) plasma waves can cause the loss of relativistic electrons into the atmosphere. Our unique set of ground and satellite observations shows coincident precipitation of ions with energies of tens of keY and of relativistic electrons into an isolated proton aurora. The coincident precipitation was produced by wave-particle interactions with EMIC waves near the plasmapause. The estimation of pitch angle diffusion coefficients supports that the observed EMIC waves caused coincident precipitation ofboth ions and relativistic electrons. This study clarifies that ions with energies of tens of ke V affect the evolution of relativistic electrons in the radiation belts via cyclotron resonance with EMIC waves, an effect that was first theoretically predicted in the early 1970's.
Boschini, M.J.; Gervasi, M.; Giani, S.; Grandi, D.; Ivantchenko, V.; Pensotti, S.; Rancoita, P.G.; Tacconi, M.
2011-01-01
In the space environment, instruments onboard of spacecrafts can be affected by displacement damage due to radiation. The differential scattering cross section for screened nucleus--nucleus interactions - i.e., including the effects due to screened Coulomb nuclear fields -, nuclear stopping powers and non-ionization energy losses are treated from about 50\\,keV/nucleon up to relativistic energies.
Stern, Boris E.; Poutanen, Juri
2008-02-01
High-energy photons propagating in the magnetized medium with large velocity gradients can mediate energy and momentum exchange. Conversion of these photons into electron-positron pairs in the field of soft photons with the consequent isotropization and emission of new high-energy photons by Compton scattering can lead to the runaway cascade of the high-energy photons and electron-positron pairs fed by the bulk energy of the flow. This is the essence of the photon breeding mechanism. We study the problem of high-energy emission of relativistic jets in blazars via photon breeding mechanism using 2D ballistic model for the jet with the detailed treatment of particle propagation and interactions. Our numerical simulations from first principles demonstrate that a jet propagating in the soft radiation field of broad emission-line region can convert a significant fraction (up to 80 per cent) of its total power into radiation. We show that the gamma-ray background of similar energy density as observed at Earth is sufficient to trigger the photon breeding. The considered mechanism produces a population of high-energy leptons and, therefore, alleviates the need for Fermi-type particle acceleration models in relativistic flows. The mechanism reproduces basic spectral features observed in blazars including the blazar sequence (shift of spectral peaks towards lower energies with increasing luminosity). The significant deceleration of the jet at subparsec scales and the transversal gradient of the Lorentz factor (so-called structured jet) predicted by the model reconcile the discrepancy between the high Doppler factors determined by the fits to the spectra of TeV blazars and the low apparent velocities observed at very long baseline interferometry (VLBI) scales. The mechanism produces significantly broader angular distribution of radiation than that predicted by a simple model assuming the isotropic emission in the jet frame. This helps to reconcile the observed statistics and
On the Stability of L4,5 in the Relativistic R3BP with Radiating ...
Indian Academy of Sciences (India)
and radiation force. The effect of oblateness and electromagnetic radiation force of the primaries on the location and the linear stability of the triangular points in the restricted three-body problem were analysed by Singh and Ishwar (1999). They considered both primaries as a source of radiation as well as oblate spheroids, ...
The Controlling Parameters for EMIC Wave Scattering of Relativistic Electrons
Zhang, X.; Li, W.; Ma, Q.; Thorne, R. M.; Angelopoulos, V.; Bortnik, J.
2016-12-01
Although there is growing support for relativistic electron losses due to precipitation from electromagnetic ion cyclotron (EMIC) wave scattering, this mechanism is yet to be quantified. Such a quantification has been difficult in the past, because equatorial electron measurements simultaneous with EMIC waves have been limited, due to the highly localized presence of EMIC waves in the magnetosphere. In this study, we examine parameters controlling characteristics of EMIC wave induced relativistic (0.3-6 MeV) electron scattering, directly based on simultaneous wave and particle measurements from Van Allen Probes. We first present a case study when relativistic electrons respond differently during two intervals of intense ( 1 nT) EMIC wave observations: one with no scattering signature and one with efficient electron losses at >1.8 MeV. Based on the observed EMIC wave spectra and background plasma conditions, we calculate the wave diffusion rates and model the evolution of electron pitch angle distributions. By comparing the modeled results with local observations of pitch angle distributions, we demonstrate that fpe/fce is critical in controlling the effectiveness of EMIC waves in scattering multi-MeV electrons. We then expand our analysis to explore the conditions (such as fpe/fce, wave frequency spectra, and ring current ion temperature and anisotropy levels) favorable for EMIC wave scattering multi-MeV electrons through multi-event analyses. Our study is important for accurately modeling relativistic electron loss processes in radiation belt electron forecasts.
Critical radiation fluxes and luminosities of black holes and relativistic stars
Lamb, Frederick K.; Miller, M. Coleman
1995-01-01
The critial luminosity at which the outward force of radiation balances the inward force of gravity plays an important role in many astrophysical systems. We present expressions for the radiation force on particles with arbitrary cross sections and analyze the radiation field produced by radiating matter, such as a disk, ring, boundary layer, or stellar surface, that rotates slowly around a slowly rotating gravitating mass. We then use these results to investigate the critical radiation flux and, where possible, the critical luminosity of such a system in genral relativity. We demonstrate that if the radiation source is axisymmetric and emission is back-front symmetric with repect to the local direction of motion of the radiating matter, as seen in the comoving frame, then the radial component of the radiation flux and the diagonal components of the radiation stress-energy tensor outside the source are the same, to first order in the rotation rates, as they would be if the radiation source and gravitating mass were not rotating. We argue that the critical radiation flux for matter at rest in the locally nonrotating frame is often satisfactory as an astrophysical benchmark flux and show that if this benchmark is adopted, many of the complications potentially introduced by rotation of the radiation source and the gravitating mass are avoided. We show that if the radiation field in the absence of rotation would be spherically symmetric and the opacity is independent of frequency and direction, one can define a critical luminosity for the system that is independent of frequency and direction, one can define a critical luminosity for the system that is independent of the spectrum and angular size of the radiation source and is unaffected by rotation of the source and mass and orbital motion of the matter, to first order. Finally, we analyze the conditions under which the maximum possible luminosity of a star or black hole powered by steady spherically symmetric radial
Energy Technology Data Exchange (ETDEWEB)
Ares de Parga, G.; Ortiz D, M.; Mares, R. [Dpto de Fisica, Escuela Superior de Fisica Matematicas, Instituto Politecnico Nacional, U.P. Adolfo Lopez Mateos, Zacatenco, 07738, Mexico D.F. (Mexico)]. e-mail: gonzalo@esfm.ipn.mx
2007-07-01
Starting with the magnetic Smirnov reaction force, a relativistic equation which describe the motion of a charged particle with constant magnetic moment of spin {mu}{sup {yields}}, is obtained. A Landau-Lifshitz-like equation is deduced with magnetic moment. A fundamental difference between the classical and relativistic radiation rate of energy is found. (Author)
Energy Technology Data Exchange (ETDEWEB)
Takahashi, Hiroyuki R. [Center for Computational Astrophysics, National Astronomical Observatory of Japan, National Institutes of Natural Sciences, Mitaka, Tokyo 181-8588 (Japan); Ohsuga, Ken, E-mail: takahashi@cfca.jp, E-mail: ken.ohsuga@nao.ac.jp [Division of Theoretical Astronomy, National Astronomical Observatory of Japan, National Institutes of Natural Sciences, Mitaka, Tokyo 181-8588 (Japan)
2017-08-10
By performing 2.5-dimensional general relativistic radiation magnetohydrodynamic simulations, we demonstrate supercritical accretion onto a non-rotating, magnetized neutron star, where the magnetic field strength of dipole fields is 10{sup 10} G on the star surface. We found the supercritical accretion flow consists of two parts: the accretion columns and the truncated accretion disk. The supercritical accretion disk, which appears far from the neutron star, is truncated at around ≃3 R {sub *} ( R {sub *} = 10{sup 6} cm is the neutron star radius), where the magnetic pressure via the dipole magnetic fields balances with the radiation pressure of the disks. The angular momentum of the disk around the truncation radius is effectively transported inward through magnetic torque by dipole fields, inducing the spin up of a neutron star. The evaluated spin-up rate, ∼−10{sup −11} s s{sup −1}, is consistent with the recent observations of the ultraluminous X-ray pulsars. Within the truncation radius, the gas falls onto a neutron star along the dipole fields, which results in a formation of accretion columns onto the northern and southern hemispheres. The net accretion rate and the luminosity of the column are ≃66 L {sub Edd}/ c {sup 2} and ≲10 L {sub Edd}, where L {sub Edd} is the Eddington luminosity and c is the light speed. Our simulations support a hypothesis whereby the ultraluminous X-ray pulsars are powered by the supercritical accretion onto the magnetized neutron stars.
Schiller, Q.; Tu, W.; Ali, A. F.; Li, X.; Godinez, H. C.; Turner, D. L.; Morley, S. K.; Henderson, M. G.
2017-03-01
The most significant unknown regarding relativistic electrons in Earth's outer Van Allen radiation belt is the relative contribution of loss, transport, and acceleration processes within the inner magnetosphere. Detangling each individual process is critical to improve the understanding of radiation belt dynamics, but determining a single component is challenging due to sparse measurements in diverse spatial and temporal regimes. However, there are currently an unprecedented number of spacecraft taking measurements that sample different regions of the inner magnetosphere. With the increasing number of varied observational platforms, system dynamics can begin to be unraveled. In this work, we employ in situ measurements during the 13-14 January 2013 enhancement event to isolate transport, loss, and source dynamics in a one-dimensional radial diffusion model. We then validate the results by comparing them to Van Allen Probes and Time History of Events and Macroscale Interactions during Substorms observations, indicating that the three terms have been accurately and individually quantified for the event. Finally, a direct comparison is performed between the model containing event-specific terms and various models containing terms parameterized by geomagnetic index. Models using a simple 3/Kp loss time scale show deviation from the event-specific model of nearly 2 orders of magnitude within 72 h of the enhancement event. However, models using alternative loss time scales closely resemble the event-specific model.
Monte Carlo simulation of cyclotron resonant scattering features
Schwarm, Fritz-Walter; Schönherr, Gabriele; Wilms, Joern
In the regime of very high magnetic fields on the order of 10(12} mathrm{G) the electron momenta perpendicular to the field are quantized due to the discrete Landau levels populated by the electrons. Parallel to the magnetic field the electrons form a continuous momentum distribution. The seed photon continuum is generated for example by bremsstrahlung or blackbody radiation. Resonant scattering of a seed photon by an electron may excite the electron to a higher Landau level. The subsequent de-excitation of the excited electron produces additional photons close to the resonance energy. This way complex cyclotron resonant scattering features (CRSFs) are imprinted on the continuum radiation. Due to the continuous electron momentum distribution parallel to the magnetic field the scattering photon's energy and angle are mixed by Lorentz transformation to the electron rest frame in which the resonant scattering process is being carried out. Therefore synthetic spectra of cyclotron lines can not be accurately calculated analytically. CRSFs have been observed in more than a dozen accreting X-ray binaries. They provide much information about the accretion structure in the observed systems since the exact line shape is sensitive to many parameters in the column. Typical parameters are for example the geometry and the spectral properties of seed photon sources, the geometry of the column, or the magnetic field and temperature within the column. We present an overview over the Monte-Carlo approach to cyclotron line simulation and show results from our texttt{cyclosim} code. Furthermore we investigate the influence of the accretion geometry on the cyclotron line shape. Our code enables us to perform fully relativistic simulations including the correct cyclotron scattering cross sections and the possibility to cope with parameter gradients such as magnetic field, temperature, or velocity gradients within the accretion column. Using a Green's function approach these simulations
Selivanova, Svetlana V; Lavallée, Éric; Senta, Helena; Caouette, Lyne; Sader, Jayden A; van Lier, Erik J; Zyuzin, Alexander; van Lier, Johan E; Guérin, Brigitte; Turcotte, Éric; Lecomte, Roger
2015-10-01
Cyclotron production of 99mTc is a promising route to supply 99mTc radiopharmaceuticals. Higher 99mTc yields can be obtained with medium-energy cyclotrons in comparison to those dedicated to PET isotope production. To take advantage of this capability, evaluation of the radioisotopic purity of 99mTc produced at medium energy (20-24 MeV) and its impact on image quality and dosimetry was required. Thick 100Mo (99.03% and 99.815%) targets were irradiated with incident energies of 20, 22, and 24 MeV for 2 or 6 h. The targets were processed to recover an effective thickness corresponding to approximately 5-MeV energy loss, and the resulting sodium pertechnetate 99mTc was assayed for chemical, radiochemical, and radionuclidic purity. Radioisotopic content in final formulation was quantified using γ-ray spectrometry. The internal radiation dose for 99mTc-pertechnetate was calculated on the basis of experimentally measured values and biokinetic data in humans. Planar and SPECT imaging were performed using thin capillary and water-filled Jaszczak phantoms. Extracted sodium pertechnetate 99mTc met all provisional quality standards. The formulated solution for injection had a pH of 5.0-5.5, contained greater than 98% of radioactivity in the form of pertechnetate ion, and was stable for at least 24 h after formulation. Radioisotopic purity of 99mTc produced with 99.03% enriched 100Mo was greater than 99.0% decay corrected to the end of bombardment (EOB). The radioisotopic purity of 99mTc produced with 99.815% enriched 100Mo was 99.98% or greater (decay corrected to the EOB). The estimated dose increase relative to 99mTc without any radionuclidic impurities was below 10% for sodium pertechnetate 99mTc produced from 99.03% 100Mo if injected up to 6 h after the EOB. For 99.815% 100Mo, the increase in effective dose was less than 2% at 6 h after the EOB and less than 4% at 15 h after the EOB when the target was irradiated at an incident energy of 24 MeV. Image spatial resolution
Dal Lago, A.; Marchezi, J. P.; Alves, L. R.; da Silva, L.; Dallaqua, R.; Medeiros, C.; Souza, V. M. C. E. S.; Rockenbach, M.; Vieira, L.; Mendes, O., Jr.; Sibeck, D. G.; Kanekal, S. G.; Kletzing, C.; Baker, D. N.; Wygant, J. R.
2016-12-01
Various physical processes can contribute to loss and acceleration of energetic electrons in the Earth's radiation belts. In the range of 1 mHz to 10 Hz, ultra-low frequency (ULF) waves are known to cause significant changes in the energetic particle flux in the radiation belts. On board the Van Allen Probes, the Relativistic Electron Proton Telescope (REPT) measures the relativistic electron flux in the outer radiation belts in the energy range from 1.8 MeV up to 20 MeV. We selected events that have significant electron flux dropouts, classified into two categories regarding the time elapsed between the outer radiation belt dropout and the refurbishing, namely events that time scale had taken (i) a few hours and, (ii) some days. This work aims to investigate the presence of ULF waves using the radial and azimuthal magnetic and electric field components recorded by the Electric and Magnetic Field Instrument Suite and Integrated Science (EMFISIS). The evaluation of the power spectral density of those components unravels the poloidal and toroidal characteristc of the rapid compressional waves. We discuss how these modes can contribute to modifications of the relativistic electron fluxes considering the (i) and (ii) cases.
Yamaguchi, Ichiro; Kimura, Ken-ichi; Fujibuchi, Toshioh; Takahashi, Yasuyuki; Saito, Kyoko; Otake, Hidenori
2011-07-01
The depth distribution of residual long-lived radioactivity in the inner concrete wall of a medical cyclotron room was measured by assaying concrete cores. Seven long-lived radioactive nuclides ((46)Sc, (60)Co, (65)Zn, (134)Cs, (152)Eu, (22)Na and (54)Mn) were identified by gamma-ray spectrometry of the concrete samples. It was confirmed that the gamma-ray-emitting radionuclides induced by thermal neutrons through the (n, γ) reaction are dominant, and that the activity induced by thermal neutrons is greater at a depth of 10-30 cm, rather than at the surface of the concrete, and decreased exponentially beyond a depth of ~40 cm. Although the specific activity at the surface was greater than the clearance level for radioactive waste indicated in IAEA RS-G-1.7, the mean specific activities in the walls and floor were less than the clearance level.
McMillan, E.M.; Judd, D.L.
1959-02-01
A cyclotron is presented embodying a unique magnetic field configuration, which configuration increases in intensity with radius and therefore compensates for the reltivistic mass effect, the field having further convolutions productive of axial stability in the particle beam. By reconciling the seemingly opposed requirements of mass increase compensation on one hand and anial stability on the other, the production of extremely high current particle beams in the relativistie energy range is made feasible. Certain further advantages inhere in the invention, notably an increase in the usable magnet gap, simplified and more efficient extraction of the beam from the accelerator, and ready adaptation to the use of multiply phased excitation as contrasted with the single phased systems herstofore utilized. General
Large-angle channeling radiation from relativistic electrons in optically transparent crystals
Korotchenko, K. B.; Pivovarov, Yu. L.
2018-02-01
In the work within the frame of quantum electrodynamics are obtained new formulae describing the large-angle photon emission from channeled electrons with taking into account of the dispersion of refractive index. Calculations based on these formulae show that the spectral and angular distributions of large-angle optical and ultraviolet radiation from planar channeled sub-GeV electrons in optically transparent crystal reflect the band structure of transverse energy levels of channeled electrons. Comparison with ordinary Cherenkov radiation spectrum reveals that channeling (depending on the beam energy) leads to sufficient change of the large-angle emission spectrum.
Directory of Open Access Journals (Sweden)
Zhen Wang
2014-09-01
Full Text Available A new scheme to generate narrow-band tunable terahertz (THz radiation using a variant of the echo-enabled harmonic generation is analyzed. We show that by using an energy chirped beam, THz density modulation in the beam phase space can be produced with two lasers having the same wavelength. This removes the need for an optical parametric amplifier system to provide a wavelength-tunable laser to vary the central frequency of the THz radiation. The practical feasibility and applications of this scheme are demonstrated numerically with a start-to-end simulation using the beam parameters at the Shanghai Deep Ultraviolet Free-Electron Laser facility (SDUV. The central frequency of the density modulation can be continuously tuned by either varying the chirp of the beam or the momentum compactions of the chicanes. The influence of nonlinear rf chirp and longitudinal space charge effect have also been studied in our article. The methods to generate the THz radiation in SDUV with the new scheme and the estimation of the radiation power are also discussed briefly.
Channeling radiation from relativistic electrons - Study of stacking faults and dislocations
Pathak, A P; Prakash-Goteti, L N S
2002-01-01
The discrete nature of the energy associated with channeled particles and consequent emission of channeling radiation has opened new applications in accelerator and atomic physics. The spontaneous transitions among various energy levels in the transverse space lead to what is known as channeling radiation. One-dimensional hydrogen atom model for continuum planar potential due to single plane is used for the case of planar channeled electrons to estimate the corresponding bound states in the potential well. The effects of extended defects like stacking faults (SFs) and dislocations on transitions among the various levels are studied by calculating the transition probabilities at the faulted region, i.e. at the SF boundary for the case of SF and distorted region of the dislocation. The obstruction and distortion effects of these extended defects are incorporated suitably to obtain initial and final populations of the eigenstates.
A Monte Carlo Code for Relativistic Radiation Transport Around Kerr Black Holes
Schnittman, Jeremy David; Krolik, Julian H.
2013-01-01
We present a new code for radiation transport around Kerr black holes, including arbitrary emission and absorption mechanisms, as well as electron scattering and polarization. The code is particularly useful for analyzing accretion flows made up of optically thick disks and optically thin coronae. We give a detailed description of the methods employed in the code and also present results from a number of numerical tests to assess its accuracy and convergence.
Zhou, Qinghua; Xiao, Fuliang; Yang, Chang; Liu, Si; He, Yihua; Baker, D. N.; Spence, H. E.; Reeves, G. D.; Funsten, H. O.
2017-06-01
Electrostatic electron cyclotron harmonic (ECH) waves generated by the electron loss cone distribution can produce efficient scattering loss of plasma sheet electrons, which has a significant effect on the dynamics in the outer magnetosphere. Here we report two ECH emission events around the same location L≈ 5.7-5.8, MLT ≈ 12 from Van Allen Probes on 11 February (event A) and 9 January 2014 (event B), respectively. The spectrum of ECH waves was centered at the lower half of the harmonic bands during event A, but the upper half during event B. The observed electron phase space density in both events is fitted by the subtracted bi-Maxwellian distribution, and the fitting functions are used to evaluate the local growth rates of ECH waves based on a linear theory for homogeneous plasmas. ECH waves are excited by the loss cone instability of 50 eV-1 keV electrons in the lower half of harmonic bands in the low-density plasmasphere in event A, and 1-10 keV electrons in the upper half of harmonic bands in a relatively high-density region in event B. The current results successfully explain observations and provide a first direct evidence on how ECH waves are generated in the lower and upper half of harmonic frequency bands.
Novel radiation sources using relativistic electrons from infrared to x-rays
Rullhusen, P; Dhez, P
1998-01-01
The purpose of this book is to give a description of the state of the art in theoretical and experimental work achieved in radiation source development. It summarizes clearly and comprehensibly, the basic physical aspects needed to understand the phenomena, and also provides the interested reader with sufficient literature to be able to follow the development in more detail. In addition, it contains a unified view of most theoretical effects and their common properties. The most recent developments as well as references to further work can be found in this volume. In many cases, review article
Kim, K. C.; Shprits, Y.; Blake, J. B.
2015-12-01
During July 2000 geomagnetic storm, known as the Bastille Day storm, SAMPEX HILT observed a strong injection of ~1 MeV electrons into the inner radiation zone (below 2 RE) during the storm main phase. Then during the recovery phase electrons are clearly diffusing inwards and forming a pronounced split-structure encompassing a narrow newly formed slot region around L=3. SAMPEX observations are first compared with electron and proton observations on NOAA POES and HEO to validate that the observed unusual dynamics is not caused by contamination by protons. In this study, we perform the time-dependent 3D Versatile Electron Radiation Belt (VERB) simulations of 1 MeV electron flux evolution and have compared the results with the SAMPEX HILT observations. The result shows that the overall time evolution of the observed split structure is in a good agreement with our model simulations. We find that this new belt at energy of ~1 MeV is resulted from scattering by plasmaspheric hiss to the Earth's atmosphere.
Cooray, G. V.; Cooray, G. K.
2011-12-01
Gurevich et al. [1] postulated that the source of narrow bipolar pulses, a class of high energy pulses that occur during thunderstorms, could be a runaway electron avalanche driven by the intense electric fields of a thunderstorm. Recently, Watson and Marshall [2] used the modified transmission line model to test the mechanism of the source of narrow bipolar pulses. In a recent paper, Cooray and Cooray [3] demonstrated that the electromagnetic fields of accelerating charges could be used to evaluate the electromagnetic fields from electrical discharges if the temporal and spatial variation of the charges in the discharge is known. In the present study, those equations were utilized to evaluate the electromagnetic fields generated by a relativistic electron avalanche. In the analysis it is assumed that all the electrons in the avalanche are moving with the same speed. In other words, the growth or the decay of the number of electrons takes place only at the head of the avalanche. It is shown that the radiation is emanating only from the head of the avalanche where electrons are being accelerated. It is also shown that an analytical expression for the radiation field of the avalanche at any distance can be written directly in terms of the e-folding length of the avalanche. This makes it possible to extract directly the spatial variation of the e-folding length of the avalanche from the measured radiation fields. In the study this model avalanche was used to investigate whether it can be used to describe the measured electromagnetic fields of narrow bipolar pulses. The results obtained are in reasonable agreement with the two station data of Eack [4] for speeds of propagation around (2 - 2.5) x 10^8 m/s and when the propagation effects on the electric fields measured at the distant station is taken into account. [1] Gurevich et al. (2004), Phys. Lett. A., 329, pp. 348 -361. [2] Watson, S. S. and T. C. Marshall (2007), Geophys. Res. Lett., Vol. 34, L04816, doi: 10
Exotic dense matter states pumped by relativistic laser plasma in the radiation dominant regime
Colgan, J; Jr.,; Faenov, A Ya; Pikuz, S A; Wagenaars, E; Booth, N; Brown, C R D; Culfa, O; Dance, R J; Evans, R G; Gray, R J; Hoarty, D J; Kaempfer, T; Lancaster, K L; McKenna, P; Rossall, A L; Skobelev, I Yu; Schulze, K S; Uschmann, I; Zhidkov, A G; Woolsey, N C
2012-01-01
The properties of high energy density plasma are under increasing scrutiny in recent years due to their importance to our understanding of stellar interiors, the cores of giant planets$^{1}$, and the properties of hot plasma in inertial confinement fusion devices$^2$. When matter is heated by X-rays, electrons in the inner shells are ionized before the valence electrons. Ionization from the inside out creates atoms or ions with empty internal electron shells, which are known as hollow atoms (or ions)$^{3,4,5}$. Recent advances in free-electron laser (FEL) technology$^{6,7,8,9}$ have made possible the creation of condensed matter consisting predominantly of hollow atoms. In this Letter, we demonstrate that such exotic states of matter, which are very far from equilibrium, can also be formed by more conventional optical laser technology when the laser intensity approaches the radiation dominant regime$^{10}$. Such photon-dominated systems are relevant to studies of photoionized plasmas found in active galactic ...
Chugunov, A. I.
2017-10-01
I suggest a novel approach for deriving evolution equations for rapidly rotating relativistic stars affected by radiation-driven Chandrasekhar-Friedman-Schutz instability. This approach is based on the multipolar expansion of gravitational wave emission and appeals to the global physical properties of the star (energy, angular momentum, and thermal state), but not to canonical energy and angular momentum, which is traditional. It leads to simple derivation of the Chandrasekhar-Friedman-Schutz instability criterion for normal modes and the evolution equations for a star, affected by this instability. The approach also gives a precise form to simple explanation of the Chandrasekhar-Friedman-Schutz instability; it occurs when two conditions are met: (a) gravitational wave emission removes angular momentum from the rotating star (thus releasing the rotation energy) and (b) gravitational waves carry less energy, than the released amount of the rotation energy. To illustrate the results, I take the r-mode instability in slowly rotating Newtonian stellar models as an example. It leads to evolution equations, where the emission of gravitational waves directly affects the spin frequency, being in apparent contradiction with widely accepted equations. According to the latter, effective spin frequency decrease is coupled with dissipation of unstable mode, but not with the instability as it is. This problem is shown to be superficial, and arises as a result of specific definition of the effective spin frequency applied previously. Namely, it is shown, that if this definition is taken into account properly, the evolution equations coincide with obtained here in the leading order in mode amplitude. I also argue that the next-to-leading order terms in evolution equations were not yet derived accurately and thus it would be more self-consistent to omit them.
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.
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 transitions of bound ions
Bezchastnov, Victor G.; Pavlov, George G.
2017-06-01
A charged particle in a magnetic field possesses discrete energy levels associated with particle rotation around the field lines. The radiative transitions between these levels are the well-known cyclotron transitions. We show that a bound complex of particles with a nonzero net charge displays analogous transitions between the states of confined motion of the entire complex in the field. The latter bound-ion cyclotron transitions are affected by a coupling between the collective and internal motions of the complex and, as a result, differ from the transitions of a "reference" bare ion with the same mass and charge. We analyze the cyclotron transitions for complex ions by including the coupling within a rigorous quantum approach. Particular attention is paid to comparison of the transition energies and oscillator strengths to those of the bare ion. Selection rules based on integrals of collective motion are derived for the bound-ion cyclotron transitions analytically, and the perturbation and coupled-channel approaches are developed to study the transitions quantitatively. Representative examples are considered and discussed for positive and negative atomic and cluster ions.
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
Ma, Kun; Chen, Zhan-Bin; Xie, Lu-You; Dong, Chen-Zhong; Qu, Yi-Zhi
2017-11-01
We present a theoretical study of relativistic effects on the linear polarization and angular distribution of x-ray radiation for the L {α }2 (3{d}3/2\\to 2{p}3/2) characteristic line following inner-shell single photoionization of Cd, Ba, Yb and Ra atoms. The analysis is performed based on the multi-configuration Dirac–Fock method and the density matrix theory. To explore the nature of these effects, calculations are carried out based on detailed analyses of the total and magnetic sublevel cross sections, the linear polarization, and the angular distribution of the x-ray photoemission, as well as on corresponding data calculated in the nonrelativistic limit. Our results show a significant difference in the above parameters compared to the nonrelativistic treatment, which is mainly due to the relativistic treatment of the target. Higher multipole contributions are also estimated, and found to be generally weaker. The importance of inclusion of the relativistic effects grows with increasing atomic number and the incoming photon energy.
Directory of Open Access Journals (Sweden)
R. Kataoka
2008-06-01
Full Text Available We report average profiles of the solar wind and outer radiation belt during the extreme flux enhancement of relativistic electrons at geosynchronous orbit (GEO. It is found that seven of top ten extreme events at GEO during solar cycle 23 are associated with the magnetosphere inflation during the storm recovery phase as caused by the large-scale solar wind structure of very low dynamic pressure (<1.0 nPa during rapid speed decrease from very high (>650 km/s to typical (400–500 km/s in a few days. For the seven events, the solar wind parameters, geomagnetic activity indices, and relativistic electron flux and geomagnetic field at GEO are superposed at the local noon period of GOES satellites to investigate the physical cause. The average profiles support the "double inflation" mechanism that the rarefaction of the solar wind and subsequent magnetosphere inflation are one of the best conditions to produce the extreme flux enhancement at GEO because of the excellent magnetic confinement of relativistic electrons by reducing the drift loss of trapped electrons at dayside magnetopause.
Vujanovic, Gojko; Paquet, Jean-François; Denicol, Gabriel S.; Luzum, Matthew; Jeon, Sangyong; Gale, Charles
2016-07-01
The penetrating nature of electromagnetic signals makes them suitable probes to explore the properties of the strongly interacting medium created in relativistic nuclear collisions. We examine the effects of the initial conditions and shear relaxation time on the spectra and flow coefficients of electromagnetic probes, using an event-by-event 3+1-dimensional viscous hydrodynamic simulation (music).
Energy Technology Data Exchange (ETDEWEB)
Gomez, P
1999-12-01
This thesis aims at characterizing the dynamics of fast electrons generated by the Landau absorption of the hybrid wave and studying their effects on electron cyclotron radiation. The different processes involved in the propagation and resonant absorption of the hybrid wave in plasmas are described. A method such as ray-tracing allows the characterization of the dynamics of heating but this method relies on the hypothesis of geometrical optics. Whenever absorption rate is low as it is in Tore-Supra, the hybrid wave undergoes a series of successive reflections on the edge of the plasma before being completely absorbed. These reflections generate an electromagnetic chaos in which geometrical optics hypothesis are no longer valid. A statistical treatment of the Fokker-Planck equation allows the calculation of the mean distribution function of electrons in the plasma submitted to hybrid wave. The electron cyclotron radiation is then deduced and by assuming that plasma behaves like a black body, a theoretical radiative temperature is calculated. The confrontation of this theoretical temperature profile with experimental values allows the validation of this modeling and the estimation of the effects of fast electrons on temperature measurements. (A.C.)
Dang, Fangchao; Zhang, Xiaoping; Zhang, Jun; Ju, Jinchuan; Zhong, Huihuang
2017-03-01
We report on a radial-line relativistic klystron oscillator (RL-RKO), which is physically designed to generate gigawatt-level high power microwaves (HPMs) at Ku-band. The 3π/4 mode of a four-gap buncher is selected to highly modulate the radially propagating intense relativistic electron beam (IREB). A three-gap extractor operating at the π mode is employed to extract the radio-frequency energy efficiently. The Ku-band RL-RKO is investigated experimentally on an intense-current electron beam accelerator. The radially propagating IREB is well focused with an axial-width of 2 mm by a radial magnetic field of 0.4 T. Microwaves with a frequency of 14.86 GHz and a power of 1.5 GW are generated, corresponding to an efficiency of 24%, which indicates a significant advance for the research of radial-line HPM sources.
Kim, S. H.
2017-12-01
We reason that in the free-electron radiation if the transition rate τ is less than the radiation frequency ν, the radiation is of broad-band spectrum whereas if τ ≫ ν, the radiation is of monochromatic. We find that when a weaker magnetic wiggler (MW) is superpositioned on a predominantly strong uniform magnetic field, free-electron two-quantum magnetic-wiggler (FETQMW) radiation takes place. In FETQMW radiation, the MW and the electron's intrinsic motivity to change its internal configuration through radiation play as two first-order perturbers while the uniform magnetic field acts as the sole zeroth-order perturber. When Δ E≪ hν, where Δ E is the uncertainty in the electron energy produced by transverse wiggling due to the MW in conjuction with a Heisenberg's uncertainty principle Δ EΔ x h and E = ( m 2 c 4 + c 2 p 2)1/2, the power of FETQMW radiation cannot exceed hν 2. However, we find that this power cap is lifted by the amount of νΔ E when Δ E ≫ hν holds [1,2]. This lift-up of the saturated radiation power is the responsible mechanism for the effective external injection of a 20 kW maser in an electron-cyclotron maser (ECM). We find that an MW-added ECM with radius 5 cm and length 1 m and operating parameters of the present beam technology can yield laser power of 50 MW at the radiation wavelength of 0.001 cm.
Westerhof, E.
2010-01-01
This lecture gives an overview of heating and current drive with electron cyclotron waves. We present the main theoretical aspects of wave propagation, wave absorption, and non-inductive current drive, as well as important technical aspects for the application of high power electron cyclotron waves,
Westerhof, E.
2012-01-01
This lecture gives an overview of heating and current drive with electron cyclotron waves. We present the main theoretical aspects of wave propagation, wave absorption, and non-inductive current drive, as well as important technical aspects for the application of high power electron cyclotron waves,
Westerhof, E.
2008-01-01
This lecture gives an overview of heating and current drive with electron cyclotron waves. We present the main theoretical aspects of wave propagation, wave absorption, and non-inductive current drive, as well as important technical aspects for the application of high power electron cyclotron waves,
Shielding design of the Mayo Clinic Scottsdale cyclotron vault
Directory of Open Access Journals (Sweden)
Riper Kenneth A. Van
2017-01-01
Full Text Available Mayo Clinic Scottsdale (Scottsdale, Arizona is building a cyclotron vault containing a cyclotron with adjacent targets and a beam line leading to an external target. The targets are irradiated by high energy (15 to 16.5 MeV protons for the production of radioisotopes. We performed Monte Carlo radiation transport simulations to calculate the radiation dose outside of the vault during irradiation of the cyclotron and external targets. We present the Monte Carlo model including the geometry, sources, and variance reduction methods. Mesh tallies surrounding the vault show the external dose rate is within acceptable limits.
Helical Phase Structure of Radiation from an Electron in Circular Motion.
Katoh, M; Fujimoto, M; Mirian, N S; Konomi, T; Taira, Y; Kaneyasu, T; Hosaka, M; Yamamoto, N; Mochihashi, A; Takashima, Y; Kuroda, K; Miyamoto, A; Miyamoto, K; Sasaki, S
2017-07-21
We theoretically show that a single free electron in circular motion radiates an electromagnetic wave possessing helical phase structure, which is closely related to orbital angular momentum carried by it. We experimentally demonstrate it by interference and double-slit diffraction experiments on radiation from relativistic electrons in spiral motion. Our results indicate that photons carrying orbital angular momentum should be created naturally by cyclotron/synchrotron radiations or Compton scatterings in various situations in cosmic space. We propose promising laboratory vortex photon sources in various wavelengths ranging from radio wave to gamma-rays.
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.
Price, R H
1993-01-01
Work reported in the workshop on relativistic astrophysics spanned a wide varicy of topics. Two speciﬁc areas seemed of particular interest. Much attention was focussed on gravitational wave sources, especially on the waveforms they produce, and progress was reported in theoretical and observational aspects of accretion disks.
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.
Jiang, Song; Li, Fucai; Xie, Feng
2015-01-01
As is well-known that the general radiation hydrodynamics models include two mainly coupled parts: one is macroscopic fluid part, which is governed by the compressible Navier-Stokes-Fourier equations, another is radiation field part, which is described by the transport equation of photons. Under the two physical approximations: "gray" approximation and P1 approximation, one can derive the so-called Navier-Stokes-Fourier-P1 approximation radiation hydrodynamics model from the general one. In t...
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.
Ion waves driven by shear flow in a relativistic degenerate ...
Indian Academy of Sciences (India)
Abstract. We investigate the existence and propagation of low-frequency (in comparison to ion cyclotron frequency) electrostatic ion waves in highly dense inhomogeneous astrophysical mag- netoplasma comprising relativistic degenerate electrons and non-degenerate ions. The dispersion equation is obtained by Fourier ...
Workshop on gravitational waves and relativistic astrophysics
Indian Academy of Sciences (India)
This workshop saw five presentations in the field of gravitational radiation and two on compact, relativistic self-gravitating systems. Gravitational waves (GWs) and black holes (BHs) are two of the most significant predictions of Einstein's relativistic theory of gravity and, as far as their experimental status is concerned, both of ...
Evidence For Acceleration of Outer Zone Electrons To Relativistic Energies By Whistler Mode Chorus
Meredith, N.; Horne, R.; Summers, D.; Thorne, R.; Iles, R.; Heynderickx, D.; Anderson, R.
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 ac- celeration mechanism to relativistic energies driven by gyroresonant interactions with whistler mode chorus. In particular, we examine the temporal evolution of the spec- tral response of the electrons and the waves during the October 9, 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 spec- tral 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. Fur- thermore, we show that the observed spectral hardening is not consistent with standard radial diffusion models. These results provide strong circumstantial evidence for a lo- cal 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 sug- gest 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.
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.
Energy Technology Data Exchange (ETDEWEB)
Bleko, V.V., E-mail: bleko_vitold@mail.ru; Konkov, A.S., E-mail: Ekwinus@tpu.ru; Soboleva, V.V.
2015-07-15
The coherent diffraction radiation (DR) and Cherenkov radiation (ChR) emitted by bunched electron beam of 6.1 MeV passing near a flat dielectric target have been observed in the millimeter wavelength range. The simple geometry of experiment allows testing different theoretical approaches, which consider the process of simultaneous emission of DR and ChR from dielectric targets. Properties of the radiation have been experimentally investigated in far-field zone. The angular distribution of the observed radiation at various tilt angles of the target in respect to the electron beam have shown the effect of interference between DR and ChR. The comparison of experimental results with the theoretical calculations based on the approach of polarization currents has been done.
On the Raman instability in degenerate relativistic plasmas
Chanturia, G. T.; Berezhiani, V. I.; Mahajan, S. M.
2017-07-01
The stimulated Raman scattering instability in a fully degenerate electron plasma is studied applying relativistic hydrodynamic and Maxwell equations. We demonstrated that the instability develops for weakly and strongly relativistic degenerate plasmas. It is shown that in the field of strong radiation, a degenerate relativistic plasma effectively responses as in the case of weak degeneracy.
Bouazza, Safa; Palmeri, Patrick; Quinet, Pascal
2017-09-01
We present a semi-empirical determination of Mo II radiative parameters in a wide wavelength range 1716-8789 Å. Our fitting procedure to experimental oscillator strengths available in the literature permits us to provide reliable values for a large number of Mo II lines, predicting previously unmeasured oscillator strengths of lines involving 4d45p and 4d35s5p odd-parity configurations. The extracted transition radial integral values are compared with ab-initio calculations: on average they are 0.88 times the values obtained with the basic pseudo-relativistic Hartree Fock method and they agree well when core polarization effects are included. When making a survey of our present and previous studies and including also those given in the literature we observe as general trends a decreasing of transition radial integral values with filling nd shells of the same principal quantum numbers for ndk(n + 1)s → ndk(n + 1)p transitions.
Baker, D N; Jaynes, A N; Kanekal, S G; Foster, J C; Erickson, P J; Fennell, J F; Blake, J B; Zhao, H; Li, X; Elkington, S R; Henderson, M G; Reeves, G D; Spence, H E; Kletzing, C A; Wygant, J R
2016-07-01
Two of the largest geomagnetic storms of the last decade were witnessed in 2015. On 17 March 2015, a coronal mass ejection-driven event occurred with a Dst (storm time ring current index) value reaching -223 nT. On 22 June 2015 another strong storm ( Dst reaching -204 nT) was recorded. These two storms each produced almost total loss of radiation belt high-energy ( E ≳ 1 MeV) electron fluxes. Following the dropouts of radiation belt fluxes there were complex and rather remarkable recoveries of the electrons extending up to nearly 10 MeV in kinetic energy. The energized outer zone electrons showed a rich variety of pitch angle features including strong "butterfly" distributions with deep minima in flux at α = 90°. However, despite strong driving of outer zone earthward radial diffusion in these storms, the previously reported "impenetrable barrier" at L ≈ 2.8 was pushed inward, but not significantly breached, and no E ≳ 2.0 MeV electrons were seen to pass through the radiation belt slot region to reach the inner Van Allen zone. Overall, these intense storms show a wealth of novel features of acceleration, transport, and loss that are demonstrated in the present detailed analysis.
Baker, D. N.; Jaynes, A. N.; Kanekal, S. G.; Foster, J.C.; Erickson, P. J.; Fennell, Joseph; Blake, J. B.; Zhao, H.; Li, X.; Elkington, S. R.;
2016-01-01
Two of the largest geomagnetic storms of the last decade were witnessed in 2015. On 17 March 2015, a coronal mass ejection-driven event occurred with a Dst (Disturbance Storm Time Ring Current Index) value reaching 223 nanoteslas. On 22 June 2015 another strong storm (Dst reaching 204 nanoteslas) was recorded. These two storms each produced almost total loss of radiation belt high-energy (E (Energy) greater than or approximately equal to 1 millielectronvolt) electron fluxes. Following the dropouts of radiation belt fluxes there were complex and rather remarkable recoveries of the electrons extending up to nearly 10 millielectronvolts in kinetic energy. The energized outer zone electrons showed a rich variety of pitch angle features including strong butterfly distributions with deep minima in flux at alpha equals 90 degrees. However, despite strong driving of outer zone earthward radial diffusion in these storms, the previously reported impenetrable barrier at L (L-shell magnetic field line value) approximately equal to 2.8 was pushed inward, but not significantly breached, and no E (Energy) greater than or approximately equal to 2.0 millielectronvolts electrons were seen to pass through the radiation belt slot region to reach the inner Van Allen zone. Overall, these intense storms show a wealth of novel features of acceleration, transport, and loss that are demonstrated in the present detailed analysis.
Research of the Electron Cyclotron Emission with Vortex Property excited by high power high frequency Gyrotron
Goto, Yuki; Kubo, Shin; Tsujimura, Tohru; Takubo, Hidenori
2017-10-01
Recently, it has been shown that the radiation from a single electron in cyclotron motion has vortex property. Although the cyclotron emission exists universally in nature, the vortex property has not been featured because this property is normally cancelled out due to the randomness in gyro-phase of electrons and the development of detection of the vortex property has not been well motivated. In this research, we are developing a method to generate the vortex radiation from electrons in cyclotron motion with controlled gyro-phase. Electron that rotates around the uniform static magnetic field is accelerated by right-hand circular polarized (RHCP) radiation resonantly when the cyclotron frequency coincides with the applied RHCP radiation frequency. A large number of electrons can be coherently accelerated in gyro-phase by a RHCP high power radiation so that these electrons can radiate coherent emission with vortex feature. We will show that vortex radiation created by purely rotating electrons for the first time.
Baryshevsky, Vladimir
2016-01-01
Until recently, the interaction of electromagnetic waves with crystals built from parallel metallic wires (wire media) was analyzed in the approximation of isotropic scattering of the electromagnetic wave by a single wire. However, if the wires are thick (kR~1), electromagnetic wave scattering by a wire is anisotropic, i.e., the scattering amplitude depends on the scattering angle. In this work, we derive the equations that describe diffraction of electromagnetic waves and spontaneous emission of charged particles in wire media, and take into account the angular dependence of scattering amplitude. Numerical solutions of these equations show that the radiation intensity increases as the wire radius is increased and achieves its maximal value in the range kR~1. The case when the condition kR~1 is fulfilled in the THz frequency range is considered in detail. The calculations show that the instantaneous power of Cherenkov and parametric (quasi-Cherenkov) radiations from electron bunches in the crystal can be tens...
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.
Exotic dense-matter states pumped by a relativistic laser plasma in the radiation-dominated regime.
Colgan, J; Abdallah, J; Faenov, A Ya; Pikuz, S A; Wagenaars, E; Booth, N; Culfa, O; Dance, R J; Evans, R G; Gray, R J; Kaempfer, T; Lancaster, K L; McKenna, P; Rossall, A L; Skobelev, I Yu; Schulze, K S; Uschmann, I; Zhidkov, A G; Woolsey, N C
2013-03-22
In high-spectral resolution experiments with the petawatt Vulcan laser, strong x-ray radiation of KK hollow atoms (atoms without n = 1 electrons) from thin Al foils was observed at pulse intensities of 3 × 10(20) W/cm(2). The observations of spectra from these exotic states of matter are supported by detailed kinetics calculations, and are consistent with a picture in which an intense polychromatic x-ray field, formed from Thomson scattering and bremsstrahlung in the electrostatic fields at the target surface, drives the KK hollow atom production. We estimate that this x-ray field has an intensity of >5 × 10(18) W/cm(2) and is in the 3 keV range.
Production of cyclotron radionuclides
Energy Technology Data Exchange (ETDEWEB)
Suh, Yong Sup; Lim, Sang Moo; Yang, Seung Dae; Chun, Kwon Soo; Ahn, Soon Hyuk; Yun, Yong Kee; Park, Hyun; Lee, Ji Sup; Lee, Jong Doo; Chai, Jong Seo; Kim, Yoo Seok; Hong, Sung Suk; Lee, Min Yong; Beak, Seung Ki [Korea Cancer Center Hospital, Seoul (Korea)
1999-12-01
In the project, 11,492mCi of {sup 201}Tl, 4,384mCi of {sup 67}Ga, 1,245mCi of {sup 123}l, 523mCi of [{sup 123}I]mlBG and 1,283mCi of {sup 18}FDG were supplied, and the revenue were 304,723,000won. In the production of RI, 13 deg for {sup 201}Tl and {sup 67}Ga, 45 deg for {sup 123}l angle solid target have been used, and liquid target system has been used for {sup 18}F production. For the efficient use of the cyclotron, the MC-50 cyclotron was opened to outside user and basic research project was carried out. The technical supports and radionuclides analysis were done during the execution of the research. Then the facilities of safety supervision and handling techniques of radioisotope production were improved. 7 refs., 9 figs., 8 tabs. (Author)
Production of cyclotron radionuclides
Energy Technology Data Exchange (ETDEWEB)
Chun, Kwon Soo; Lim, Sang Moo; Yang, Seung Dae; Suh, Yong Sup; Ahn, Soon Hyuk; Yun, Yong Kee; Park, Hyun; Lee, Ji Sup; Chai, Jong Seo; Kim, Yoo Seok; Hong, Sung Suk; Lee, Min Yong; Beak, Seung Ki; Kim, Jang Hye; Kim, Gi Sup [Korea Cancer Center Hospital, Seoul (Korea)
2000-12-01
In the project, 12,077mCi of {sup 201}Tl, 5,717mCi of {sup 67}Ga, 2,096mCi of {sup 123}l, 482mCi of [{sup 123}I]mlBG and 2,738mCi of {sup 18}FDG were supplied, and the revenue were 387,253,000won. In the production of RI, 13 deg for {sup 201}Tl and {sup 67}Ga, 45 deg for {sup 123}l angle solid target have been used, and liquid target system has been used for {sup 18}F production. For the efficient use of the cyclotron, the MC-50 cyclotron was opened to outside user and basic research project was carried out. The technical supports and radionuclides analysis were done during the execution of the research. Then the facilities of safety supervision and handling techniques of radioisotope production were improved. 7 refs., 8 figs., 9 tabs. (Author)
Limits and signatures of relativistic spaceflight
Yurtsever, Ulvi; Wilkinson, Steven
2018-01-01
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 photons from an ultra-relativistic object may create radiation with a characteristic signature allowing the detection of such objects at large distances.
Photon and gluon emission in relativistic plasmas
Arnold, Peter; Moore, Guy D.; Yaffe, Laurence G.
2002-06-01
We recently derived, using diagrammatic methods, the leading-order hard photon emission rate in ultra-relativistic plasmas. This requires a correct treatment of multiple scattering effects which limit the coherence length of emitted radiation (the Landau-Pomeranchuk-Migdal effect). In this paper, we provide a more physical derivation of this result, and extend the treatment to the case of gluon radiation.
Energy Technology Data Exchange (ETDEWEB)
Musabaeva, L. I., E-mail: musabaevaLI@oncology.tomsk.ru; Lisin, V. A., E-mail: Lisin@oncology.tomsk.ru [Tomsk Cancer Research Institute, Kooperativny Street 5, Tomsk, 634050 (Russian Federation); Startseva, Zh. A., E-mail: zhanna.alex@rambler.ru; Gribova, O. V., E-mail: gribova79@mail.ru; Velikaya, V. V., E-mail: viktoria.v.v@inbox.ru [Tomsk Cancer Research Institute, Kooperativny Street 5, Tomsk, 634050 (Russian Federation); National Research Tomsk Polytechnic University, Lenin Avenue 30, Tomsk, 634050 (Russian Federation)
2016-08-02
The analysis of clinical use of neutron therapy with 6 MeV fast neutrons compared to conventional radiation therapy was carried out. The experience of using neutron and mixed neutron and photon therapy in patients with different radio-resistant malignant tumors shows the necessity of further studies and development of the novel approaches to densely-ionizing radiation. The results of dosimetry and radiobiological studies have been the basis for planning clinical programs for neutron therapy. Clinical trials over the past 30 years have shown that neutron therapy successfully destroys radio-resistant cancers, including salivary gland tumors, adenoidcystic carcinoma, inoperable sarcomas, locally advanced head and neck tumors, and locally advanced prostate cancer. Radiation therapy with 6.3 MeV fast neutrons used alone and in combination with photon therapy resulted in improved long-term treatment outcomes in patients with radio-resistant malignant tumors.
Operation of a quasioptical electron cyclotron maser
Energy Technology Data Exchange (ETDEWEB)
Morse, E.C.; Pyle, R.V.
1984-12-01
The electron cyclotron maser or gyrotron concept has been developed to produce sources producing 200 kW at 28 GHz continuously, and higher power outputs and frequencies in pulsed mode. These sources have been useful in electron cyclotron resonance heating (ECRH) in magnetically confined fusion devices. However, higher frequencies and higher power levels will be required in reactor-grade fusion plasmas, with likely requirements of 1.0 MW or more per source at 140 GHz. Conventional gyrotrons follow a trend of decreasing power for increasing frequency. In order to circumvent this problem, the quasioptical electron cyclotron maser was proposed. In this device, the closed resonator of the conventional gyrotron is replaced with an open, Fabry-Perot type resonator. The cavity modes are then the TEM-type modes of an optical laser. The advantage of this configuration is that the cavity size is not a function of frequency, since the length can be any half-integer number of wavelengths. Furthermore, the beam traverses across the cavity transverse to the direction of radiation output, and thus the rf window design is less complicated than in conventional tubes. The rf output, if obtained by diffraction coupling around one of the mirrors, could be in a TEM mode, which would allow for quasioptical transmission of the microwaves into the plasma in fusion devices. 4 references, 1 figure.
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)
Risk assessment of 30 MeV cyclotron facilities
Energy Technology Data Exchange (ETDEWEB)
Jeong, Gyo Seong; Lee, Jin Woo [Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup (Korea, Republic of); Kim, Chong Yeal [Dept. of Radiation Science and Technology, Chonbuk National University, Jeonju (Korea, Republic of)
2017-03-15
A cyclotron is a kind of particle accelerator that produces a beam of charged particles for the production of medical, industrial, and research radioisotopes. More than 30 cyclotrons are operated in Korea to produce 18F, an FDG synthesis at hospitals. A 30-MeV cyclotron was installed at ARTI (Advanced Radiation Technology Institute, KAERI) mainly for research regarding isotope production. In this study, we analyze and estimate the items of risk such as the problems in the main components of the cyclotron, the loss of radioactive materials, the leakage of coolant, and the malfunction of utilities, fres and earthquakes. To estimate the occurrence frequency in an accident risk assessment, five levels, i.e., Almost certain, Likely, Possible, Unlikely, and Rare, are applied. The accident consequence level is classified under four grades based on the annual permissible dose for radiation workers and the public in the nuclear safety law. The analysis of the accident effect is focused on the radioactive contamination caused by radioisotope leakage and radioactive material leakage of a ventilation filter due to a free. To analyze the risks, Occupation Safety and Health Acts is applied. In addition, action plans against an accident were prepared after a deep discussion among relevant researchers. In this acts, we will search for hazard and introduce the risk assessment for the research 30-MeV cyclotron facilities of ARTI.
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.
Weller, R.R.
1995-02-14
An ion cyclotron resonance cell is disclosed having two adjacent sections separated by a center trapping plate. The first section is defined by the center trapping plate, a first end trapping plate, and excitation and detector electrodes. The second section includes a second end trapping plate spaced apart from the center plate, a mirror, and an analyzer. The analyzer includes a wavelength-selective light detector, such as a detector incorporating an acousto-optical device (AOD) and a photodetector. One or more ion guides, grounded plates with holes for the ion beam, are positioned within the vacuum chamber of the mass spectrometer between the ion source and the cell. After ions are trapped and analyzed by ion cyclotron resonance techniques in the first section, the ions of interest are selected according to their mass and passed into the second section for optical spectroscopic studies. The trapped ions are excited by light from a laser and caused thereby to fluoresce. The fluorescent light emitted by the excited ions is reflected by the mirror and directed onto the detector. The AOD is scanned, and the photodetector output is recorded and analyzed. The ions remain in the second section for an extended period, enabling multiple studies to be carried out on the same ensemble of ions. 5 figs.
Relativistic quantum mechanics and introduction to field theory
Energy Technology Data Exchange (ETDEWEB)
Yndurain, F.J. [Universidad Autonoma de Madrid (Spain). Dept. de Fisica Teorica
1996-12-01
The following topics were dealt with: relativistic transformations, the Lorentz group, Klein-Gordon equation, spinless particles, spin 1/2 particles, Dirac particle in a potential, massive spin 1 particles, massless spin 1 particles, relativistic collisions, S matrix, cross sections, decay rates, partial wave analysis, electromagnetic field quantization, interaction of radiation with matter, interactions in quantum field theory and relativistic interactions with classical sources.
Relativistic-microwave theory of ball lightning
H.-C. Wu
2016-01-01
Ball lightning, a fireball sometimes observed during lightnings, has remained unexplained. Here we present a comprehensive theory for the phenomenon: At the tip of a lightning stroke reaching the ground, a relativistic electron bunch can be produced, which in turn excites intense microwave radiation. The latter ionizes the local air and the radiation pressure evacuates the resulting plasma, forming a spherical plasma bubble that stably traps the radiation. This mechanism is verified by partic...
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
Evidence for acceleration of outer zone electrons to relativistic energies by whistler mode chorus
Directory of Open Access Journals (Sweden)
N. P. Meredith
2002-07-01
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-particle interactions
Energy Technology Data Exchange (ETDEWEB)
Ta Phuoc, K
2002-10-15
The aim of this work is to design a new source of X-radiation that is both femtosecond and polychromatic. We have studied the Larmor radiation emitted during the relativistic interaction between an intense femtosecond laser and an under dense helium plasma. When the value of a{sub 0}, the laser force parameter, is below 1 and when the interaction is volume is important, the characteristics of the emitted radiation are those of Bremsstrahlung radiation and radiative recombination. When the value of a{sub 0} is about 5 the emitted radiation is strongly different and look like much more the Larmor radiation. Nevertheless some features such as the shape of the angular distribution or the amplitude of the laser polarization effect are not yet well understood. The spectra of the X-ray produced is peaked around 150 eV and spreads up to 2 keV. The number of photons produced by laser shot is over 10{sup 9} and the duration of the X-ray impulse is expected to be in the same order of magnitude as that of the laser impulse: 30 fs. The average photon flux is 2*10{sup 3} ph/s/0.1%BW at 2 keV and reaches 6*10{sup 7} ph/s/0.1%BW at 0.15 keV. The average brilliance is 1.5*10{sup 4} ph/s/mm{sup 2}/mrad{sup 2}/0.1%BW at 2 keV and 8*10{sup 4} ph/s/mm{sup 2}/mrad{sup 2}/0.1%BW at 0.15 keV. Different ways are considered to improve the characteristics of this new X-ray source. (A.C.)
Energy Technology Data Exchange (ETDEWEB)
Kipping, David, E-mail: dkipping@astro.columbia.edu [Department of Astronomy, Columbia University, 550 W. 120th St., New York, NY 10027 (United States)
2017-06-01
One proposed method for spacecraft to reach nearby stars is by accelerating sails using either solar radiation pressure or directed energy. This idea constitutes the thesis behind the Breakthrough Starshot project, which aims to accelerate a gram-mass spacecraft up to one-fifth the speed of light toward Proxima Centauri. For such a case, the combination of the sail’s low mass and relativistic velocity renders previous treatments incorrect at the 10% level, including that of Einstein himself in his seminal 1905 paper introducing special relativity. To address this, we present formulae for a sail’s acceleration, first in response to a single photon and then extended to an ensemble. We show how the sail’s motion in response to an ensemble of incident photons is equivalent to that of a single photon of energy equal to that of the ensemble. We use this principle of ensemble equivalence for both perfect and imperfect mirrors, enabling a simple analytic prediction of the sail’s velocity curve. Using our results and adopting putative parameters for Starshot , we estimate that previous relativistic treatments underestimate the spacecraft’s terminal velocity by ∼10% for the same incident energy. Additionally, we use a simple model to predict the sail’s temperature and diffraction beam losses during the laser firing period; this allows us to estimate that, for firing times of a few minutes and operating temperatures below 300°C (573 K), Starshot will require a sail that absorbs less than one in 260,000 photons.
Kipping, David
2017-06-01
One proposed method for spacecraft to reach nearby stars is by accelerating sails using either solar radiation pressure or directed energy. This idea constitutes the thesis behind the Breakthrough Starshot project, which aims to accelerate a gram-mass spacecraft up to one-fifth the speed of light toward Proxima Centauri. For such a case, the combination of the sail’s low mass and relativistic velocity renders previous treatments incorrect at the 10% level, including that of Einstein himself in his seminal 1905 paper introducing special relativity. To address this, we present formulae for a sail’s acceleration, first in response to a single photon and then extended to an ensemble. We show how the sail’s motion in response to an ensemble of incident photons is equivalent to that of a single photon of energy equal to that of the ensemble. We use this principle of ensemble equivalence for both perfect and imperfect mirrors, enabling a simple analytic prediction of the sail’s velocity curve. Using our results and adopting putative parameters for Starshot, we estimate that previous relativistic treatments underestimate the spacecraft’s terminal velocity by ˜10% for the same incident energy. Additionally, we use a simple model to predict the sail’s temperature and diffraction beam losses during the laser firing period; this allows us to estimate that, for firing times of a few minutes and operating temperatures below 300°C (573 K), Starshot will require a sail that absorbs less than one in 260,000 photons.
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 effects on the modulational instability of electron plasma ...
Indian Academy of Sciences (India)
netosphere [2], Van Allen radiation belts [3] and laser–plasma interaction experiments. [4]. The relativistic motion in plasmas is assumed to exist during the early evolution of the Universe [5]. Studies on relativistic effects on ion-acoustic solitary waves are many. Das and Paul [6] first investigated the ion-acoustic solitary ...
Self-Consistent Ring Current/Electromagnetic Ion Cyclotron Waves Modeling
Khazanov, G. V.; Gamayunov, K.; Gallagher, D.
2006-12-01
The self-consistent treatment of ring current (RC) ion dynamics and electromagnetic ion cyclotron (EMIC) waves, which are thought to exert important influences on dynamic ion evolution and are an important missing element in our understanding of the storm-and recovery-time ring current evolution. For example, the EMIC waves cause the RC decay on a time scale of about one hour or less during the main phase of storms. The oblique EMIC waves damp due to Landau resonance with the thermal plasmaspheric electrons, and subsequent transport of the dissipating wave energy into the ionosphere below causes an ionosphere temperature enhancement. Under certain conditions, relativistic electrons, with energies ~1 MeV, can be removed from the outer radiation belt by EMIC wave scattering during a magnetic storm. That is why the modeling of EMIC waves is a critical and timely issue in magnetospheric physics. This study will generalize the self-consistent theoretical description of RC ions and EMIC waves that has been developed by Khazanov et al. [2002, 2003] and include the heavy ions and propagation effects of EMIC waves in global dynamic modeling of self-consistent RC - EMIC waves coupling. The results of our newly developed model will be presented, focusing mainly on the dynamics of EMIC waves and comparison of these results with the previous global RC modeling studies devoted to EMIC waves formation. We will also discuss RC ion precipitations and wave induced thermal electron fluxes into the ionosphere.
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).
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...
Cyclotron for Beam Therapy Application
Alenitsky, Yu G; Karamysheva, G A; Kostromin, S A; Mitsyn, G V; Molokanov, A G; Onishchenko, L M; Samsonov, E V; Vorozhtsov, S B; Zaplatin, N L
2005-01-01
The basic parameters of the proton isochronous cyclotron on the fixed energy are considered. The energy of protons is $E_{p}\\sim $ 220~MeV, intensity of the extracted beam is $I_{p}\\sim $ 0.1~$\\mu$A. The cyclotron is projected on the basis of compact magnet with four sectors and the diameter of poles 300 cm. Two dees of the accelerating system are located in valleys.
Energy Technology Data Exchange (ETDEWEB)
Guimaraes, Adriana, E-mail: amgr@cdtn.b [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil). Programa de Pos-Graduacao em Ciencia e Tecnologia das Radiacoes, Minerais e Materiais; Rodrigues, Sergio Luiz Moreira; Andrade, Ricardo Severino [Centro de Desenvolvimento da Tecnologia Nuclear (SECPRA/CDTN/CNEN-MG), Belo Horizonte, MG (Brazil). Servico de Pesquisa e Producao de Radiofarmacos; Lacerda, Marco Aurelio de Sousa [Centro de Desenvolvimento da Tecnologia Nuclear (SEPRA/CDTN/CNEN-MG), Belo Horizonte, MG (Brazil). Servico de Protecao Radiologica; Silva, Teogenes Augusto da [Centro de Desenvolvimento da Tecnologia Nuclear (SERAS/CDTN/CNEN-MG), Belo Horizonte, MG (Brazil). Servico das Radiacoes Aplicadas a Saude
2011-10-26
Use activation foils of {sup 115}In were evaluated for study of neutron radiation field surrounding a non shielded 16.5 MeV cyclotron, during the production of fluorine-18. Two foils of {sup 115}In were used which were exposed to the neutron flux of target-chamber of the GEPETtrace-8 of CDTN/CNEN, Brazil. The first foil were positioned in front of cyclotron beam, and the second one in the diametral opposed position to the beam. It was possible to distinguish for the first foil the 417 keV photo peaks, attributed to the thermal and the 417 keV neutrons attributed to the fast neutrons. On the second foil it was only distinguished the 417 keV photopeak. The results had shown that it is possible to evaluate the fast and thermal neutron fraction surrounding the cyclotron by using indium foils. However, the short half life of the {sup 115}In makes unviable the simultaneous irradiation of a great number of foils
Kumar, Rajeev; Sonkawade, Rajendra G; Tripathi, Madhavi; Sharma, Punit; Gupta, Priyanka; Kumar, Praveen; Pandey, Anil K; Bal, Chandrasekhar; Damle, Nishikant Avinash; Bandopadhayaya, Gurupad
2014-01-01
Our aim was to establish an easy and convenient procedure for the preparation of fluorine-18-sodium fluoride ((18)F-NaF) for bone positron emission tomography (PET) during routine (18)F-FDG production using the Explora FDG4 radiochemistry module (EFRM) by single run of Cyclotron with negligible radiation exposure. We compared three techniques for (18)F-NaF production during routine PET radiochemistry at our setup. In one method we used synthesis module and in other two methods we did not. In the first and third method, F-18 was directly extracted from the V-vial and in the second method, (18)F-NaF was extracted by post processing from the EFRM. In the first method, F-18 was extracted directly from V-vial manually by opening the V-vial cap. In the second method, Explora FDG-4 Module was used. First, F-18 was transferred from the V-vial. Then, after post processing in EFRM, pure F-18 was obtained in the product vial. In the third method, pure F-18 was obtained in the product vial with the help of a mechanical robotic arm. The above were followed by routine quality control of (18)F-NaF produced by each method. Results of quality control of the (18)F-NaF obtained by all three methods satisfied all parameters prescribed by the United States Pharmacopeia (USP) and the British Pharmacopeia (BP) including biological, physical and chemical specifications. The radiochemical purity was 98.5±1.5% with Rf 0.006. The level of Kryptofix-222 (K222) in (18)F-NaF was within the prescribed limit. Mean pH of (18)F-NaF was 6.0±1.5. The exposure rate around the hot cell was negligible. In conclusion, from the results it was obvious that by our method number three (18)F-NaF was directly obtained from the V-vial using mechanical robotic arms. This method was the most appropriate with minimized radiation exposure to the handling Radiochemist and was also saving time as compared to the other two methods.
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…
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.
Energy Technology Data Exchange (ETDEWEB)
Geloni, Gianluca [European XFEL GmbH, Hamburg (Germany); Kocharyan, Vitali; Saldin, Evgeni [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)
2017-04-15
;'true'' particle trajectory vector x(t) calculated or measured in the conventional way, and covariant particle trajectory vector x{sub cov}(t) calculated by projecting the world line to the lab frame (t(τ),x{sub 1}(τ),x{sub 2}(τ),x{sub 3}(τ)) and using the lab time t to parameterize the trajectory curve. In other words, for a relativistic motion accelerated along a curved trajectory, the results of conventional particle tracking differ from those of covariant particle tracking. The difference is only due to a choice of convention, but only vector x{sub cov}(t) is consistent with the usual Maxwell's equations. This essential point has never received attention in the physical community. As a result, a correction of the conventional synchrotron-cyclotron radiation theory is required.
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.
Astrophysical Applications of Relativistic Shear Flows
Liang, Edison
2017-10-01
We review recent PIC simulation results of relativistic collisionless shear flows in both 2D and 3D. We apply these results to spine-sheath jet models of blazars and gamma-ray-bursters, and to shear flows near the horizon of rapidly spinning black holes. We will discuss magnetic field generation, particle energization and radiation processes, and their observational consequences.
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.
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.
Towards relativistic quantum geometry
Directory of Open Access Journals (Sweden)
Luis Santiago Ridao
2015-12-01
Full Text Available 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.
Norbury, John W.
Nuclear fission reactions induced by the electromagnetic field of relativistic nuclei are studied for energies relevant to present and future relativistic heavy ion accelerators. Cross sections are calculated for U-238 and Pu-239 fission induced by C-12, Si-28, Au-197, and U-238 projectiles. It is found that some of the cross sections can exceed 10 b.
Conjugate Observations of EMIC Waves and Precipitation of Relativistic Electrons
Wang, Dedong; Shprits, Yuri; Yuan, Zhigang; Yu, Xiongdong; Huang, Shiyong
2017-04-01
Utilizing data from NOAA Geostationary Operational Environmental Satellite (GOES)-12 and low-altitude Polar Orbiting Environmental Satellites (POES)-15, a well-conjugate observation of Electromagnetic Ion Cyclotron (EMIC) waves and precipitation of ring current ions and relativistic electrons is reported. This event took place in periods without geomagnetic storms at near 21:30 on June 19, 2008. During this interval, GOES-12 observed EMIC waves at geosynchronous orbit in dusk Magnetic Local Time (MLT) sector. Conjugately, low-altitude NOAA POES-15 observed precipitation of ring current ions and relativistic electrons. To our knowledge, this is the best conjugated observation from satellites to illustrate EMIC wave-driven Relativistic Electron Precipitation (REP) in the MLT dusk sector during non-storm periods. The REP was observed by POES-15 at the same L (the radial distance in the equatorial plane under dipolar geomagnetic model) and MLT as where EMIC waves were observed by GOES-12, and the projections along the geomagnetic field line of NOAA GOES-12 and POES-15 at the altitude of 100 km above the Earth are nearly at the same geomagnetic latitude and longitude (△MLAT 0.7°, △MLong 0.6°). The diffusion coefficients of relativistic electrons by the EMIC waves are also calculated. This event suggests that, during the periods without geomagnetic storms, EMIC waves can also cause the loss of ring current ions and relativistic electrons through pitch-angle scattering in the dusk sector.
Relativistic versus non-relativistic mean field
Reinhard, Paul-Gerhard
Three variants of the relativistic mean-field model (RMF) and the nonrelativistic Skyrme-Hartree-Fock model (SHF) are compared. Overall quality, predictive power, and correlations between observables are addressed using statistical analysis on the basis of least squares fits. Appropriate density dependence is a crucial ingredient for good performance of RMF. However, SHF shows still more flexibility particularly in the isovector channel.
Energy Technology Data Exchange (ETDEWEB)
Chae, Jong Seo; Lee, Dong Hoon; Kim, You Seok; Park, Chan Won; Lee, Yong Min; Hong, Sung Seok; Lee, Min Yong
1995-12-01
The first cyclotron in Korea, MC-59 cyclotron is used for neutron irradiation, radionuclide development, production and material and biomedical research. 50.5MeV and 35MeV proton beam have been extracted with 20-70 .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 23days. Fundamental data for failure decrement and efficient beam extraction were composed and maintenance technologies were developed. (author). 8 tabs., 17 figs., 10 refs.
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.
Relativistic-microwave theory of ball lightning
Wu, H.-C.
2016-06-01
Ball lightning, a fireball sometimes observed during lightnings, has remained unexplained. Here we present a comprehensive theory for the phenomenon: At the tip of a lightning stroke reaching the ground, a relativistic electron bunch can be produced, which in turn excites intense microwave radiation. The latter ionizes the local air and the radiation pressure evacuates the resulting plasma, forming a spherical plasma bubble that stably traps the radiation. This mechanism is verified by particle simulations. The many known properties of ball lightning, such as the occurrence site, relation to the lightning channels, appearance in aircraft, its shape, size, sound, spark, spectrum, motion, as well as the resulting injuries and damages, are also explained. Our theory suggests that ball lighting can be created in the laboratory or triggered during thunderstorms. Our results should be useful for lightning protection and aviation safety, as well as stimulate research interest in the relativistic regime of microwave physics.
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.
Relativistic Length Agony Continued
Redzic, D. V.
2014-06-01
We made an attempt to remedy recent confusing treatments of some basic relativistic concepts and results. Following the argument presented in an earlier paper (Redzic 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.
Bliokh, Konstantin Y; Nori, Franco
2012-03-23
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 Lorentz transformations of the AM tensor. We examine manifestations of the relativistic Hall effect in quantum vortices and mechanical flywheels and also discuss various fundamental aspects of this 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.
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.
Energy Technology Data Exchange (ETDEWEB)
Antippa, Adel F [Departement de Physique, Universite du Quebec a Trois-Rivieres, Trois-Rivieres, Quebec G9A 5H7 (Canada)
2009-05-15
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 method that can be applied to a wide range of special relativistic problems of linear acceleration.
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 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.
Bremsstrahlung from relativistic heavy ions in matter
DEFF Research Database (Denmark)
Sørensen, Allan Hvidkjær
2010-01-01
The emission of electromagnetic radiation by relativistic bare heavy ions penetrating ordinary matter is investigated. Our main aim is to determine the bremsstrahlung which we define as the radiation emitted when the projectile does not break up. It pertains to collisions without nuclear contact....... As a result of its relative softness, bremsstrahlung never dominates the energy-loss process for heavy ions. As to the emission of electromagnetic radiation in collisions with nuclear break-up, it appears modest when pertaining to incoherent action of the projectile nucleons in noncontact collisions...
Mechanism for electron cyclotron heating of collisionless plasma
Energy Technology Data Exchange (ETDEWEB)
Golovanivskii, K.S.; Dugard-Jabon, V.D.; Milant' ev, V.P.
1975-01-01
The electron distribution with respect to transverse energy is derived for electron cyclotron resonance in a constant, homogeneous magnetic field; weak relativistic effects are taken into account. After the establishment of a steady-state distribution with groups of hot and cold electrons, no energy is pumped from the rf field to the plasma. The rf electrostatic perturbations are studied on the basis of the distribution function found; it is shown that waves of two types are unstable eigenmodes of the plasma at rest and drift waves. The growth rates for the corresponding instabilities are derived. A study is also made of the stability of right-handed circularly polarized electromagnetic wave propagating along the magnetic field. Instabilities occur at frequencies which depend on the degree of anisotropy, analogous to the case of a plasma with a temperature anisotropy.
Rotating black hole solutions in relativistic analogue gravity
Giacomelli, Luca; Liberati, Stefano
2017-09-01
Simulation and experimental realization of acoustic black holes in analogue gravity systems have lead to a novel understanding of relevant phenomena such as Hawking radiation or superradiance. We explore here the possibility of using relativistic systems for simulating rotating black hole solutions and possibly get an acoustic analogue of a Kerr black hole. In doing so, we demonstrate a precise relation between nonrelativistic and relativistic solutions and provide a new class of vortex solutions for relativistic systems. Such solutions might be used in the future as a test bed in numerical simulations as well as concrete experiments.
Experimental monitoring of ozone production in a PET cyclotron facility
Energy Technology Data Exchange (ETDEWEB)
Zanibellato, L. [Department of Energetic, Nuclear and Environmental Control, University of Bologna (Italy); Cicoria, G.; Pancaldi, D. [Department of Medical Physics, University Hospital ' S.Orsola-Malpighi' , Bologna (Italy); Boschi, S. [PET Radiopharmacy Unit, Department of Nuclear Medicine, University Hospital ' S.Orsola-Malpighi' , Bologna (Italy); Mostacci, D. [Department of Energetic, Nuclear and Environmental Control, University of Bologna (Italy); Marengo, M., E-mail: marengo@med.unibo.i [Department of Medical Physics, University Hospital ' S.Orsola-Malpighi' , Bologna (Italy)
2010-10-15
Ozone produced from radiolytic processes was investigated as a possible health hazard in the working environment at the University Hospital 'S.Orsola-Malpighi' PET facility. Intense radiation fields can generate ozone, known to be the most toxic gas produced by ionizing radiation around a particle accelerator. To evaluate ozone concentration in air, two different measurement campaigns were conducted with passive diffusion detectors. Comparison of the results with the concentration limits recommended by American Conference of Governmental Industrial Hygienists (ACGIH) demonstrated that ozone poses no health hazard to workers around a biomedical cyclotron.
Why NASA and the Space Electronics Community Cares About Cyclotrons
LaBel, Kenneth A.
2017-01-01
NASA and the space community are faced with the harsh reality of operating electronic systems in the space radiation environment. Systems need to work reliably (as expected for as long as expected) and be available during critical operations such as docking or firing a thruster. This talk will provide a snapshot of the import of ground-based research on the radiation performance of electronics. Discussion topics include: 1) The space radiation environment hazard, 2) Radiation effects on electronics, 3) Simulation of effects with cyclotrons (and other sources), 4) Risk prediction for space missions, and, 5) Real-life examples of both ground-based testing and space-based anomalies and electronics performance. The talk will conclude with a discussion of the current state of radiation facilities in North America for ground-based electronics testing.
The cyclotron laboratory and the RFQ accelerator in Bern
Braccini, S.; Ereditato, A.; Kreslo, I.; Nirkko, M.; Scampoli, P.; von Bremen, K.; Weber, M.
2013-07-01
Two proton accelerators have been recently put in operation in Bern: an 18 MeV cyclotron and a 2 MeV RFQ linac. The commercial IBA 18/18 cyclotron, equipped with a specifically conceived 6 m long external beam line ending in a separate bunker, will provide beams for routine 18-F and other PET radioisotope production as well as for novel detector, radiation biophysics, radioprotection, radiochemistry and radiopharmacy developments. The accelerator is embedded into a complex building hosting two physics laboratories and four Good Manufacturing Practice (GMP) laboratories. This project is the result of a successful collaboration between the Inselspital, the University of Bern and private investors, aiming at the constitution of a combined medical and research centre able to provide the most cutting-edge technologies in medical imaging and cancer radiation therapy. The cyclotron is complemented by the RFQ with the primary goals of elemental analysis via Particle Induced Gamma Emission (PIGE), and the detection of potentially dangerous materials with high nitrogen content using the Gamma-Resonant Nuclear Absorption (GRNA) technique. In this context, beam instrumentation devices have been developed, in particular an innovative beam profile monitor based on doped silica fibres and a setup for emittance measurements using the pepper-pot technique. On this basis, the establishment of a proton therapy centre on the campus of the Inselspital is in the phase of advanced study.
The cyclotron laboratory and the RFQ accelerator in Bern
Energy Technology Data Exchange (ETDEWEB)
Braccini, S.; Ereditato, A.; Kreslo, I.; Nirkko, M.; Weber, M. [Albert Einstein Center for Fundamental Physics, Laboratory for High Energy Physics (LHEP), University of Bern, Sidlerstrasse 5, CH-3012 Bern (Switzerland); Scampoli, P. [Albert Einstein Center for Fundamental Physics, Laboratory for High Energy Physics (LHEP), University of Bern, Sidlerstrasse 5, CH-3012 Bern, Switzerland and Department of Physical Sciences, University Federico II, Via Cintia, I-60126 Napoli (Italy); Bremen, K. von [SWAN Isotopen AG, Inselspital, CH-3010 Bern (Switzerland)
2013-07-18
Two proton accelerators have been recently put in operation in Bern: an 18 MeV cyclotron and a 2 MeV RFQ linac. The commercial IBA 18/18 cyclotron, equipped with a specifically conceived 6 m long external beam line ending in a separate bunker, will provide beams for routine 18-F and other PET radioisotope production as well as for novel detector, radiation biophysics, radioprotection, radiochemistry and radiopharmacy developments. The accelerator is embedded into a complex building hosting two physics laboratories and four Good Manufacturing Practice (GMP) laboratories. This project is the result of a successful collaboration between the Inselspital, the University of Bern and private investors, aiming at the constitution of a combined medical and research centre able to provide the most cutting-edge technologies in medical imaging and cancer radiation therapy. The cyclotron is complemented by the RFQ with the primary goals of elemental analysis via Particle Induced Gamma Emission (PIGE), and the detection of potentially dangerous materials with high nitrogen content using the Gamma-Resonant Nuclear Absorption (GRNA) technique. In this context, beam instrumentation devices have been developed, in particular an innovative beam profile monitor based on doped silica fibres and a setup for emittance measurements using the pepper-pot technique. On this basis, the establishment of a proton therapy centre on the campus of the Inselspital is in the phase of advanced study.
TRIUMF cyclotron vacuum system refurbishing
Sekachev, I.
2008-03-01
The cyclotron at TRIUMF was commissioned to full energy in 1974. The volume of the cyclotron vacuum tank is about 100 m3 and it operates at 5×10-8 Torr pressure during beam production. The pumping is mainly based on a Phillips B-20 cryogenerator (Stirling cycle 4-cylinder engine). The cryogenerator supplies helium gas at 16 K and 70 K to cryopanels in the tank. The decreasing reliability of the B-20 and demanding maintenance requirements triggered the decision to completely overhaul or replace the cryogenerator. Replacement with the LINDE-1630 helium refrigerator was found to be the most attractive (technically and economically) option. The details of the proposal with installation of the helium refrigerator and with a continuous flow liquid nitrogen shield cooling system are presented.
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.
Mittleman, R; Palmer, F; Gabrielse, G.; Dehmelt, H.
1991-01-01
By substituting the relativistic spin state dependence of the cyclotron frequency for the continuous Stern-Gerlach effect and running the geonium atom as a microsynchrocyclotron accelerator we have detected spin flips of the individual trapped electron. In our initial efforts we have been able to obtain a simple symmetric spin resonance about 4-fold narrower instead of a complex asymmetric one and also to support but not as yet seriously test the result of the earlier geonium "S" work, g/2 = ...
Neutron spectra due (13)N production in a PET cyclotron.
Benavente, J A; Vega-Carrillo, H R; Lacerda, M A S; Fonseca, T C F; Faria, F P; da Silva, T A
2015-05-01
Monte Carlo and experimental methods have been used to characterize the neutron radiation field around PET (Positron Emission Tomography) cyclotrons. In this work, the Monte Carlo code MCNPX was used to estimate the neutron spectra, the neutron fluence rates and the ambient dose equivalent (H*(10)) in seven locations around a PET cyclotron during (13)N production. In order to validate these calculations, H*(10) was measured in three sites and were compared with the calculated doses. All the spectra have two peaks, one above 0.1MeV due to the evaporation neutrons and another in the thermal region due to the room-return effects. Despite the relatively large difference between the measured and calculated H*(10) for one point, the agreement was considered good, compared with that obtained for (18)F production in a previous work. Copyright © 2015 Elsevier Ltd. All rights reserved.
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.
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...
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...
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.
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.
Hojo, S; Katagiri, K; Nakao, M; Sugiura, A; Muramatsu, M; Noda, A; Okada, T; Takahashi, Y; Komiyama, A; Honma, T; Noda, K
2014-02-01
The Kei-source is a compact electron cyclotron resonance ion source using only permanent magnets and a frequency of 10 GHz. It was developed at the National Institute of Radiological Sciences (NIRS) for producing C(4+) ions oriented for high-energy carbon therapy. It has also been used as an ion source for the NIRS-930 cyclotron. Its microwave band region for the traveling-wave-tube amplifier and maximum output power are 8-10 GHz and 350 W, respectively. Since 2006, it has provided various ion beams such as proton, deuteron, carbon, oxygen, and neon with sufficient intensity (200 μA for proton and deuteron, 50 μA for C(4+), for example) and good stability for radioisotope production, tests of radiation damage, and basic research experiments. Its horizontal and vertical emittances were measured using a screen monitor and waist-scan. The present paper reports the current status of the Kei-source.
Hojo, S.; Katagiri, K.; Nakao, M.; Sugiura, A.; Muramatsu, M.; Noda, A.; Okada, T.; Takahashi, Y.; Komiyama, A.; Honma, T.; Noda, K.
2014-02-01
The Kei-source is a compact electron cyclotron resonance ion source using only permanent magnets and a frequency of 10 GHz. It was developed at the National Institute of Radiological Sciences (NIRS) for producing C4+ ions oriented for high-energy carbon therapy. It has also been used as an ion source for the NIRS-930 cyclotron. Its microwave band region for the traveling-wave-tube amplifier and maximum output power are 8-10 GHz and 350 W, respectively. Since 2006, it has provided various ion beams such as proton, deuteron, carbon, oxygen, and neon with sufficient intensity (200 μA for proton and deuteron, 50 μA for C4+, for example) and good stability for radioisotope production, tests of radiation damage, and basic research experiments. Its horizontal and vertical emittances were measured using a screen monitor and waist-scan. The present paper reports the current status of the Kei-source.
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.
2011-12-27
...-0292] International Cyclotron, Inc., Hato Rey, Puerto Rico; Order Suspending Licensed Activities I International Cyclotron, Inc. (International Cyclotron; Licensee) is the holder of Byproduct Materials License... International Cyclotron submitted its NRC license application related to the cyclotron, it requested...
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
Relativistic configuration interaction approach
Indian Academy of Sciences (India)
level of reliability and accuracy in accounting for both relativistic and correlation effects associated with these properties has gained importance. In this paper, we will compute one of the P, ... this procedure provides reasonable accuracy with small computational cost. Titov and co-workers have also reported the result of Wd.
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…
Indian Academy of Sciences (India)
Home; Journals; Pramana – Journal of Physics; Volume 77; Issue 3. Relativistic stellar models ... Upon specifying particular forms for one of the gravitational potentials and the electric ﬁeld intensity, the condition for pressure isotropy is transformed into a hypergeometric equation with two free parameters. For particular ...
Atkinson, David
A Zenonian supertask involving an infinite number of identical colliding balls is generalized to include balls with different masses. Under the restriction that the total mass of all the balls is finite, classical mechanics leads to velocities that have no upper limit. Relativistic mechanics results
Relativistic Quantum Information Theory
2007-11-20
Relativistic Quantum Information Theory Army Research Office Grant # DAAD -0301-0207 Christoph Adami November 16, 2007 1 Foreword The stated goal of the...the future will allow us to finish the work we started. A List of manuscripts produced under ARO grant # DAAD - 0301-0207 All these manuscripts
Energy Technology Data Exchange (ETDEWEB)
Paroli, B., E-mail: bruno.paroli@unimi.it [Dipartimento di Fisica, Universitá degli Studi di Milano and INFN Sezione di Milano, via G. Celoria 16, 20133 Milano (Italy); Chiadroni, E.; Ferrario, M. [INFN-LNF, via E. Fermi, 00044 Frascati (Italy); Potenza, M.A.C. [Dipartimento di Fisica, Universitá degli Studi di Milano and INFN Sezione di Milano, via G. Celoria 16, 20133 Milano (Italy)
2016-12-11
We show the results of a systematic study of the properties recently evidenced for the asymmetric lateral coherence of broadband radiation emitted by particles in betatron motion. 2-dimensional Montecarlo simulations have been used in order to investigate changes of the coherence properties by varying the spatial distribution of an ensemble of particles, whose parameters match those of the electron beams at the SPARC-LAB test facility. A clear interpretation is given under several conditions, and applications to diagnostics of particle beams appear a natural exploitation of the coherence measurements.
Zhu, H.; Shprits, Y. Y.; Spasojevic, M.; Kellerman, A. C.; Drozdov, A.
2016-12-01
New wave frequency and amplitude models for nightside and dayside chorus waves are developed based on measurement from the Electric and Magnetic Field Instrument Suite and Integrated Science (EMFISIS) instrument on board Van Allen Probes. New paremetrizations can be used for quiet, moderate and disturbed conditions. The corresponding 3D diffusion coefficients are calculated using the Full Diffusion Code. The new parameterizations result in differences in the diffusion coefficients as a function of both electron energy and pitch angle. Furthermore, one-year 3D simulations are performed using the Versatile Electron Radiation Belt (VERB) code. Simulations with new parametrizations show better agreement with observations.
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.
PRODUCTION OF 11 C-METHIONINE BY CYCLOTRON AVF JAERI
Directory of Open Access Journals (Sweden)
Sri Hastini
2010-06-01
Full Text Available At the Takasaki-site of JAERI, an AVF cyclotron has been constructed for advanced radiation technology research. The cyclotron produces extracted beams particularly light and heavy ions of proton as well as deutron. Target chamber is available for production of 11CO2 a positron emitter radioisotope, by bombardment of proton from nitrogen gas as a target, by 14 N (p,a 11C reaction. The use of incident energy on target was estimated to be 11 MeV for primary proton energy of 20 MeV and the beam current was 0,1 m A and the irradiation time was 10 minutes for production of 11CO2 and the yield was about 30 MBq (EOBand for irradiation time 15 minutes and the beam current was 1 mA for production of 11C-Methionine, the yield was about 70 MBq (EOB. Remotely operated automatic and semiautomatic processing systems are used for the production of the 11 C-Methionine agent and the radiochemical purity of the product obtained was determined by High Performance Liquid Chromatography (HPLC with cation exchange column was LC 10 AD MERCK LICHROSPHER 100 RP-18 and the mobile phase was 10 mM ammonium phormmate, the mean of retention time was 1,815 minutes and the radiochemical purity to be more than 90 %. The product was used for plant studies and visualized by PETIS (Positron Emission Tracer Imaging System Keywords: cyclotron, Positron emitter, 11C-Methionine.
Relativistic Electron Pitch Angle Distributions in the Inner Magnetosphere
Friedel, Reiner; Zhao, Hong; Reeves, Geoff; Chen, Yue; Henderson, Mike; Kanekal, Shri; Baker, Dan; Jaynes, Allison
2017-04-01
Relativistic electron pitch angle distributions (PADs) in the trapped inner region of the magnetosphere are a sensitive measure of many processes that govern the dynamics of these particles. We report here on statistical observations of relativistic electron PADs from the REPT (Relativistic Electron/Proton Telescope) instrument aboard the Van Allen Probes mission, which show an unexpected dawn/dusk asymmetry that seems to be a persistent feature during quiet times of Dst > -20 nT. The observed PADs show a more peaked pancake distribution at dusk compared to dawn for energies above 1.8 MeV only. Energies from a few 100 KeV to 1 m,eV do NOT show these asymmetries, ruling out magnetic field model effects. These observations hint at persistent processes that can act on relativistic electrons on timescales on the order of the outer radiation belt drift period (10 minutes).
On the origin of cyclotron lines in the spectra of X-ray pulsars
Directory of Open Access Journals (Sweden)
Mushtukov A. A.
2014-01-01
Full Text Available Cyclotron resonance scattering features are observed in the spectra of some X-ray pulsars and show significant changes in the line energy with the pulsar luminosity. In a case of bright sources, the line centroid energy is anti-correlated with the luminosity. Such a behaviour is often associated with the onset and growth of the accretion column, which is believed to be the origin of the observed emission and the cyclotron lines. However, this scenario inevitably implies large gradient of the magnetic field strength within the line-forming region, and it makes the formation of the observed line-like features problematic. Moreover, the observed variation of the cyclotron line energy is much smaller than could be anticipated for the corresponding luminosity changes. We argue that a more physically realistic situation is that the cyclotron line forms when the radiation emitted by the accretion column is reflected from the neutron star surface. The idea is based on the facts that a substantial part of column luminosity is intercepted by the neutron star surface and the reflected radiation should contain absorption features. The reflection model is developed and applied to explain the observed variations of the cyclotron line energy in a bright X-ray pulsar V 0332+53 over a wide range of luminosities.
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...
DEFF Research Database (Denmark)
Jensen, Tue Vissing; Sørensen, Allan Hvidkjær
2013-01-01
A charged particle emits bremsstrahlung while traversing matter. We calculate the radiation cross section for bare heavy ions penetrating amorphous materials and single crystals at highly relativistic energies. The main component originates in scattering of the virtual photons of screened target...... in a pronounced directional dependence of the energy loss of bare heavy ions at extreme relativistic energies....
Three-wave interaction during electron cyclotron resonance heating and current drive
DEFF Research Database (Denmark)
Nielsen, Stefan Kragh; Jacobsen, Asger Schou; Hansen, Søren Kjer
2016-01-01
Non-linear wave-wave interactions in fusion plasmas, such as the parametric decay instability (PDI) of gyrotron radiation, can potentially hamper the use of microwave diagnostics. Here we report on anomalous scattering in the ASDEX Upgrade tokamak during electron cyclotron resonance heating...
Evaluating the Role and Effects of Precipitation on Relativistic Electron Losses during Storms
Chen, Y.; Fu, X.
2016-12-01
Theoretic studies have suggested that during storm times various waves (e.g., whistler-mode chorus and electromagnetic ion cyclotron waves) can cause significant precipitation of relativistic ( MeV) electrons that are originally trapped inside the outer radiation belt. However, the role of precipitation and its quantitative contribution to the losses of outer-belt electrons remain open questions. In this study, we tackle these questions by systemically examining the latest wave and electron in-situ, simultaneous observations made at different altitudes by Van Allen Probes from near equator, NOAA POES at low Earth orbits near/across electron loss cone, and BARREL under the mesosphere. After calibrating with DEMTER observations, we first confirm and quantify the response of POES MEPED proton channels to MeV electrons. Next, we identify a list of precipitation events from BARREL and POES measurements, examine the temporal adn spatial relation between the two data sets, and estimate the intensities of electron precipitation with ascertained uncertainties. Then, from Van Allen Probes data, we select another list of dropout events during storms. By cross checking the above two lists, we are able to determine the causal relation between precipitation and dropouts through individual case as well as statistical studies so as to quantify the contributions from precipitation. This study mainly focuses on the relatively small L-shells with positive phase space density radial gradient in order to alleviate the impacts from outward radial diffusion and adiabatic effects. Based upon the recent discovery of cross-energy cross-pitch angle coherence, we pay particular attention to the cross-term diffusions which may account for the extra "loss" needed by observed MeV electron dropouts. Results from this observational study will advance our knowledge on the loss mechanism of outer-belt electrons, and thus lay down another stepping stone towards high-fidelity physics-based models for
Correlation electron cyclotron emission diagnostic in TCV
Fontana, M.; Porte, L.; Molina Cabrera, P.
2017-08-01
The correlation electron cyclotron emission diagnostic of tokamak à configuration variable has recently been upgraded. It now has the choice of three lines of sight: two horizontal lines placed on the low field side of the vessel, perpendicular to the magnetic field, and a dual-axis steerable antenna. The polarization of the radiation collected by the latter can be rotated using a universal polarizer situated in the transmission line. This line is also shared with a reflectometry system, allowing simultaneous measurements of temperature and density fluctuations in the same plasma volumes. When using this line, it is possible to choose between two dedicated front ends characterized by different local oscillator frequencies, adding flexibility in the choice of the plasma region to be studied. The intermediate frequency section is now equipped with six frequency tunable YIG filters allowing the study of turbulence properties in a wide range of radial positions. When studying fluctuations over the whole video bandwidth, the minimum detectable fluctuation level is δ Te/Te˜0.5 % . The new system has been used to measure electron temperature fluctuations over a large fraction of the plasma profiles in a series of plasmas with triangularity varying from 0.6 to -0.6 but comparable collisionality profiles.
Excitation of dust kinetic Alfven waves by semi-relativistic ion beams
Energy Technology Data Exchange (ETDEWEB)
Rubab, N. [Department of Space Science, Institute of Space Technology, Islamabad (Pakistan); Jaffer, G. [Department of Space Science, University of the Punjab, Lahore (Pakistan)
2016-05-15
The growth rates for dust kinetic Alfvén wave (DKAW) based on semi-relativistic Maxwellian distribution function are investigated in a hot and magnetized plasma. The dispersion relation of DKAW is obtained on a dust acoustic velocity branch, and the kinetic instability due to cross-field semi-relativistic ion flow is examined by the effect of dust parameters. Analytical expressions are derived for various modes as a natural consequence of the form of the solution, and is shown through graphical representation that the presence of dust particles and the cross-field semi-relativistic ions sensibly modify the dispersion characteristics of low-frequency DKAW. The results are valid for a frequency regime well below the dust cyclotron frequency. We suggest that semi-relativistic particles are an important factor in the growth/damping of DKAWs. It is also found that relativistic effects appear with the dust lower hybrid frequency are more effective for dust kinetic Alfvén waves in the perpendicular component as compared to the parallel one. In particular, the relativistic effects associated with electrons suppress the instability while ions enhance the growth rates. The growth rates are significantly modified with dust parameters and streaming velocity of cross-field ions.
Cherenkov wakefield excitation by relativistic electron beams in plasma channels
Wang, Tianhong; Khudik, Vladimir; Shvets, Gennday
2017-10-01
We report on our theoretical investigations of Cherenkov radiation excited by relativistic electron bunches propagating in plasma channels and in polaritonic channels. Two surface plasmons (SPs) modes of the radiation are analyzed: the longitudinal (accelerating) and the transverse (deflecting) ones. Both form Cherenkov cones that are different in the magnitude of the cone angle and the central frequency. We show that the Cherenkov field profile change dramatically depending on the driver velocity and the channel size, and the longitudinal mode forms a reversed Cherenkov radiation cone due to the negative group velocity for sufficiently small air gaps. In addition, we find that when the channel surface is corrugated, a strong deflecting wake is excited by a relativistic electron bunch. A trailing electron bunch experiencing this wake is forced to undergo betatron oscillations and thus to emit radiation. Numerical simulation showed that intense x-ray radiation can be generated.
A relativistic trolley paradox
Matvejev, Vadim N.; Matvejev, Oleg V.; Grøn, Ø.
2016-01-01
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 p R ,where R is the radius of the wheel, but 2 p R = ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi...
The relativistic glider revisited
Bergamin, L.; Delva, P.; Hees, A.
2009-01-01
In this paper we analyze some aspects of the "relativistic glider" proposed by Gu\\'eron and Mosna more in detail. In particular an explicit weak gravity and low velocity expansion is presented, the influence of different initial conditions are studied and the behavior of the glider over a longer integration time is presented. Our results confirm that the system can be used as a glider, but is not able to stop or even revert the fall of an object.
The Electron Cyclotron Resonance Light Source Assembly of PTB - ELISA
Gruebling, P; Ulm, G
1999-01-01
In the radiometry laboratory of the Physikalisch-Technische,Bundesanstalt at the Berlin electron storage ring BESSY I, radiation sources for radiometric applications in industry and basic research in the vacuum ultraviolet (VUV) spectral range are developed, characterized and calibrated. Established sources such as deuterium lamps, Penning and hollow cathode discharge sources have limited spectral ranges and in particular their stability and life time suffers from the erosion of the cathode material. To overcome these limitations we have developed a radiation source based on the principle of the electron cyclotron resonance ion source. ELISA is a 10 GHz monomode source with a compact design featuring a tunable cavity and axially positionable permanent magnets. The radiation emission of the source can be detected simultaneously in the VUV and X-ray spectral range via a toroidal grating monochromator and a Si(Li)-detector. The special design of the source allows spectroscopic investigations of the plasma in dep...
Relativistic tidal disruption events
Directory of Open Access Journals (Sweden)
Levan A.
2012-12-01
Full Text Available In March 2011 Swift detected an extremely luminous and long-lived outburst from the nucleus of an otherwise quiescent, low luminosity (LMC-like galaxy. Named Swift J1644+57, its combination of high-energy luminosity (1048 ergs s−1 at peak, rapid X-ray variability (factors of >100 on timescales of 100 seconds and luminous, rising radio emission suggested that we were witnessing the birth of a moderately relativistic jet (Γ ∼ 2 − 5, created when a star is tidally disrupted by the supermassive black hole in the centre of the galaxy. A second event, Swift J2058+0516, detected two months later, with broadly similar properties lends further weight to this interpretation. Taken together this suggests that a fraction of tidal disruption events do indeed create relativistic outflows, demonstrates their detectability, and also implies that low mass galaxies can host massive black holes. Here, I briefly outline the observational properties of these relativistic tidal flares observed last year, and their evolution over the first year since their discovery.
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.
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.
Cyclotrons: From Science to Human Health
Craddock, Michael
2011-04-01
Lawrence's invention of the cyclotron, whose 80th anniversary we have just celebrated, not only revolutionized nuclear physics, but proved the starting point for a whole variety of recirculating accelerators, from the smallest microtron to the largest synchrotron, that have had an enormous impact in almost every branch of science and in several areas of medicine and industry. Cyclotrons themselves have proved remarkably adaptable, incorporating a variety of new ideas and technologies over the years: frequency modulation, edge focusing, AG focusing, separate magnet sectors, axial and azimuthal injection, ring geometries, stripping extraction, superconducting magnets and rf...... Even FFAGs, those most complex members of the cyclotron (fixed-magnetic-field) family, are making a comeback. Currently there are more than 50 medium or large cyclotrons around the world devoted to research. These provide intense primary beams of protons or stable ions, and correspondingly intense secondary beams of neutrons, pions, muons and radioactive ions, for experiments in nuclear, particle and condensed-matter physics, and in the materials and life sciences. Far outnumbering these, however, are the 800 or so small and medium cyclotrons used to produce radioisotopes for medical and other purposes. In addition, a rapidly growing number of 230-MeV proton cyclotrons are being built for cancer therapy -12 brought into operation since 1998 and as many more in the works. Altogether, cyclotrons are flourishing!
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
Dielectric effects on Thomson scattering in a relativistic magnetized plasma
DEFF Research Database (Denmark)
Bindslev, H.
1991-01-01
The effects of the dielectric properties of a relativistic magnetized plasma on the scattering of electromagnetic radiation by fluctuations in electron density are investigated. The origin of the density fluctuations is not considered. Expressions for the scattering cross-section and the scattered...
Transport models for relativistic heavy-ion collisions at Relativistic ...
Indian Academy of Sciences (India)
2015-04-29
Apr 29, 2015 ... Transport models for relativistic heavy-ion collisions at Relativistic Heavy Ion Collider and Large Hadron Collider. Subrata Pal. Volume 84 Issue 5 May 2015 pp ... Subrata Pal1. Department of Nuclear and Atomic Physics, Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400 005, India ...
Weibel instability in relativistic electron positron plasma
Ehsan, Zahida; Tsintsadze, Nodar; Yoon, Peter
2017-10-01
We consider a situation in when the interaction of relativistically intense EM waves with an isotropic electron positron? plasma takes place, i.e., we consider short pulse lasers with intensity up to 1021 W/cm2, in which the photon density is of the order of 1030cm-3 and the strength of electric field E = 109 statvolt/cm. Such a situation is possible in astrophysical and laboratory plasmas which are subject to intense laser radiation, thus leading to nonthermal equilibrium field radiations. Such interaction of the superstrong laser radiation with an isotropic pair plasma leads to the generation of low frequency electromagnetic EM waves and in particular a quasistationary magnetic field. When the relativistic circularly polarized transverse EM wave propagates along z-axis, it creates a ponderomotive force, which affects the motion of particles along the direction of its propagation. On the other hand, motion of the particles across the direction of propagation is defined by the ponderomotive potential. Moreover dispersion relation for the transverse EM wave using a special distribution function, which has an anisotropic form, is derived and is subsequently investigated for a number of special cases. In general, it is shown that the growth rate of the EM wave strongly depends upon its intensity.
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.
10 GHz ECRIS for Warsaw Cyclotron
Sudlitz, K
1999-01-01
Cusp type, 10 GHz ECRIS has been built and tested earlier. For obtaining intensive beams, more relevant for cyclotron, cusp geometry has been replaced by hexapole. Discharge chamber (stainless steel, 50 mm diameter, 250 mm long) is an extension of a coaxial line, feeding RF (9,6 GHz, up to 200 W) to the plasma. The NdFeB hexapole (0,52 T on the surface) has been used. The axial magnetic field is created by water cooled coils. The axial injection line dedicated to K160 isochronous heavy ion cyclotron has been constructed. The line consists of Glaser lenses, double focusing magnet, solenoid and mirror type inflector. The system provides sufficient transmission of the beam from ECR ion source to the firsts orbits of the cyclotron for m/q ranging from 7 to 2. After successful initial tests which were done in July 1997 the ECRIS serves as an external source for Warsaw Cyclotron.
Relativistic effects in the pionium lifetime
Energy Technology Data Exchange (ETDEWEB)
Jallouli, H.; Sazdjian, H.
1997-12-31
Pionium decay width is evaluated in the framework of chiral perturbation theory and the relativistic bound state formalism of constraint theory. Corrections of order O({alpha}) are calculated with respect to the conventional lowest-order formula, in which the strong interaction amplitude has been calculated to two-loop order with charged pion masses. Strong interaction corrections, electromagnetic radiative corrections due to pion-photon interactions, electromagnetic mass shift insertions in internal propagators and correction due to the passage from the strong interaction scattering amplitude are calculated. (author). 53 refs.
Relativistic Dynamics of Graphene
Semenoff, Gordon
2011-10-01
Graphene is a one-atom thick layer of carbon atoms where electrons obey an emergent Dirac equation. Only seven years after it first became available in the laboratory, graphene has captured the attention of a wide spectrum of scientists: from particle physicists interested in using graphene's emergent relativistic dynamics to study quantum field theory phenomena to condensed matter physicists fascinated by its unusual electronic propertied and technologists searching for materials for the nest generation of electronic devices. This presentation will review the basics of graphene and some questions, such as the possibility of chiral symmetry breaking, which have overlap with similar ones in strong interaction particle physics.
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.
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
Relativistic dissipative fluids
Geroch, R
1993-01-01
We observe in Nature ﬂuids that manifest dissipation, e.g., the effects of heat conductivity and viscosity. We believe that all physical phenomena are to be described within the framework of General Relativity. What, then, is the appropriate description of a relativistic dissipative ﬂuid? This is not only a question of principle, but also one of practical interest. There exist systems, such as certain neutron stars, in which relativity and dissipation are at the same time signiﬁcant.
Cyclotron axial ion-beam-buncher system
Energy Technology Data Exchange (ETDEWEB)
Hamm, R.W.; Swenson, D.A.; Wangler, T.P.
1982-02-11
Adiabatic ion bunching is achieved in a cyclotron axial ion injection system through the incorporation of a radio frequency quadrupole system, which receives ions from an external ion source via an accelerate-decelerate system and a focusing einzel lens system, and which adiabatically bunches and then injects the ions into the median plane of a cyclotron via an electrostatic quadrupole system and an inflection mirror.
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.
relline: Relativistic line profiles calculation
Dauser, Thomas
2015-05-01
relline calculates relativistic line profiles; it is compatible with the common X-ray data analysis software XSPEC (ascl:9910.005) and ISIS (ascl:1302.002). The two basic forms are an additive line model (RELLINE) and a convolution model to calculate relativistic smearing (RELCONV).
Pelletier, Guy; Bykov, Andrei; Ellison, Don; Lemoine, Martin
2017-07-01
Relativistic astrophysical collisionless shocks represent outstanding dissipation agents of the huge power of relativistic outflows produced by accreting black holes, core collapsed supernovae and other objects into multi-messenger radiation (cosmic rays, neutrinos, electromagnetic radiation). This article provides a theoretical discussion of the fundamental physical ingredients of these extreme phenomena. In the context of weakly magnetized shocks, in particular, it is shown how the filamentation type instabilities, which develop in the precursor of pair dominated or electron-ion shocks, provide the seeds for the scattering of high energy particles as well as the agent which preheats and slows down the incoming precursor plasma. This analytical discussion is completed with a mesoscopic, non-linear model of particle acceleration in relativistic shocks based on Monte Carlo techniques. This Monte Carlo model uses a semi-phenomenological description of particle scattering which allows it to calculate the back-reaction of accelerated particles on the shock structure on length and momentum scales which are currently beyond the range of microscopic particle-in-cell (PIC) simulations.
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.
Energy Technology Data Exchange (ETDEWEB)
Ujevic, Maximiliano [Universidade Federal do ABC (UFABC), Santo Andre, SP (Brazil). Centro de Ciencias Naturais e Humanas; Letelier, Patricio S.; Vogt, Daniel [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Inst. de Matematica, Estatistica e Computacao Cientifica. Dept. de Matematica Aplicada
2011-07-01
Full text: Relativistic thick ring models are constructed using previously found analytical Newtonian potential-density pairs for flat rings and toroidal structures obtained from Kuzmin-Toomre family of discs. This was achieved by inflating previously constructed Newtonian ring potentials using the transformation |z|{yields}{radical}z{sup 2} + b{sup 2}, and then finding their relativistic analog. The models presented have infinite extension but the physical quantities decays very fast with the distance, and in principle, one could make a cut-off radius to consider it finite. In particular, we present systems with one ring, two rings and a disc with a ring. Also, the circular velocity of a test particle and its stability when performing circular orbits are presented in all these models. Using the Rayleigh criterion of stability of a fluid at rest in a gravitational field, we find that the different systems studied present a region of non-stability that appears in the intersection of the disc and the ring, and between the rings when they become thinner. (author)
Relativistic Planck-scale polymer
Amelino-Camelia, Giovanni; Arzano, Michele; Da Silva, Malú Maira; Orozco-Borunda, Daniel H.
2017-12-01
Polymer quantum mechanics has been studied as a simplified picture that reflects some of the key properties of Loop Quantum Gravity; however, while the fate of relativistic symmetries in Loop Quantum Gravity is still not established, it is usually assumed that the discrete polymer structure should lead to a breakdown of relativistic symmetries. We here focus for simplicity on a one-spatial-dimension polymer model and show that relativistic symmetries are deformed, rather than being broken. The specific type of deformed relativistic symmetries which we uncover appears to be closely related to analogous descriptions of relativistic symmetries in some noncommutative spacetimes. This also contributes to an ongoing effort attempting to establish whether the ;quantum-Minkowski limit; of Loop Quantum Gravity is a noncommutative spacetime.
Yang, Xiaochao; Ni, Binbin; Yu, Jiang; Zhang, Yang; Zhang, Xiaoxin; Sun, Yueqiang
2017-06-01
Using multisatellite measurements, a uniquely strong and long-lived relativistic electron slot region refilling event from November 2004 to January 2005 is investigated. This event occurred under remarkable interplanetary and magnetospheric conditions. Both empirically modeled and observationally estimated plasmapause locations demonstrate that the plasmasphere eroded significantly prior to the enhancement phase of this event. The estimated diffusion coefficients indicate that the radial diffusion due to ULF waves is insufficient to account for the observed enhancement of slot region electrons. However, the diffusion coefficients evaluated using the distribution of chorus wave intensities derived from low-altitude POES electron observations indicate that the local acceleration induced by chorus could account for the major feature of observed enhancement outside the plasmapause. When the plasmasphere recovered, the refilled slot region was enveloped inside the plasmapause. In the plasmasphere, while the efficiency of hiss scattering loss increases by including unusually low frequency hiss waves, the interaction with hiss alone cannot fully explain the decay of this event, especially at higher energies, which suggests that electromagnetic ion cyclotron waves contribute to the relativistic electron loss process at such low L shells for this refilling event. Through a comprehensive analysis on the basis of data analyses and numerical calculations, the present study sheds light on the underlying physics responsible for the unusual slot refilling by relativistic electrons, which exhibits the complexity of both radiation belt electron dynamics and associated wave-particle interactions.
Understanding the bursty electron cyclotron emission during a sawtooth crash in the HT-7 tokamak
Energy Technology Data Exchange (ETDEWEB)
Li, Erzhong, E-mail: rzhonglee@ipp.ac.cn; Hu, Liqun; Chen, Kaiyun [Institute of Plasma Physics, Chinese Academy of Science, Hefei 230031 (China)
2014-01-15
Bursts in electron cyclotron emission (ECE) were observed during sawtooth crashes in HT-7 in discharges with ion cyclotron resonance heating injected near the q = 1 rational surface (q is the safety factor). The local ECE measurement indicated that the bursty radiation is only observed on channels near but a little away outward from the q = 1 magnetic surface. In conjunction with the soft x-ray tomography analysis, it was determined that, for the first time, only a compression process survives in the later stage of fast magnetic reconnection but before prompt heat transport. The compression enhanced the electron radiation temperature, the increased amplitude of which agreed well with the estimation according to a kinetic compression theory model [R. J. Hastie and T. C. Hender, Nucl. Fusion 28, 585 (1988)]. This paper presents the experimental evidence that there indeed exists a transient compression phase which results in the bursty ECE radiation during a sawtooth crash.
Understanding the bursty electron cyclotron emission during a sawtooth crash in the HT-7 tokamak
Li, Erzhong; Hu, Liqun; Chen, Kaiyun
2014-01-01
Bursts in electron cyclotron emission (ECE) were observed during sawtooth crashes in HT-7 in discharges with ion cyclotron resonance heating injected near the q = 1 rational surface (q is the safety factor). The local ECE measurement indicated that the bursty radiation is only observed on channels near but a little away outward from the q = 1 magnetic surface. In conjunction with the soft x-ray tomography analysis, it was determined that, for the first time, only a compression process survives in the later stage of fast magnetic reconnection but before prompt heat transport. The compression enhanced the electron radiation temperature, the increased amplitude of which agreed well with the estimation according to a kinetic compression theory model [R. J. Hastie and T. C. Hender, Nucl. Fusion 28, 585 (1988)]. This paper presents the experimental evidence that there indeed exists a transient compression phase which results in the bursty ECE radiation during a sawtooth crash.
Efficient 58-GHz relativistic orotron with combined mode selection
Totmeninov, E. M.; Pegel, I. V.; Tarakanov, V. P.
2017-05-01
This article presents time-dependent numerical modeling of V-band relativistic orotron: a high-power microwave generator with a TM03 oscillation mode in an oversized (D/λ ˜ 2.7) electrodynamic structure and diffractive output in the TM02 mode. Single-mode operation of the oscillator is ensured by the cyclotron selection of the working axisymmetric mode, with simultaneous depression of competing non-axisymmetric modes by means of cutting longitudinal slits in the wall of the slow-wave structure. The simulated output microwave power is 350 MW with a power conversion efficiency of 31% when using a 3.6 kA, 310 keV electron beam transported in the 3.9 T magnetic field. The simulation employed 2.5D axisymmetric and 3D Cartesian versions of the KARAT code.
Wang, D.
2016-12-01
Electromagnetic Ion Cyclotron (EMIC) waves are believed to be able to pitch-angle scatter ring current ions and relativistic electrons leading to the precipitation of them. Utilizing data from GOES and NOAA Polar Orbiting Environmental Satellites (POES), a conjugate observation of EMIC waves and precipitation of ring current ions and relativistic electrons is found. This event took place under quiet geomagnetic conditions. During this interval, GOES satellite observed EMIC waves at geosynchronous orbit in dusk MLT sector. Conjugately, during this interval, low-altitude NOAA POES satellite observed precipitation of ring current ions and relativistic electrons. To our knowledge, this is the best conjugated observation by satellites to illustrate EMIC wave-driven Relativistic Electron Precipitation (REP) in the Magnetic Local Time (MLT) dusk sector. The REP was observed by NOAA POES at the same L and MLT as where EMIC wave was observed by GOES, and the projections of GOES and NOAA POES on the Earth along the geomagnetic field line are nearly at the same geomagnetic latitude and longitude (△MLAT 0.7°, △MLong 0.6°). This event suggests that, during the quiet geomagnetic conditions, EMIC waves can also cause the loss of ring current ions and relativistic electrons through pitch-angle scattering in the dusk sector.
Cyclotron facilities in Brazil: Current status and licensing aspects
Energy Technology Data Exchange (ETDEWEB)
Facure, A.; Carvalho, S.M.; Di Prinzio, R.; Silveira, C.S.; Gasparian, P.B.R.; Franca, W.F., E-mail: facure@cnen.gov.br [Comissao Nacional de Energia Nuclear (CNEN), Rio de Janeiro, RJ (Brazil)
2017-09-01
Positron Emission Tomography (PET) is a highly sensitive and accurate nuclear medicine imaging technology but the major problem of this technique is the use of radioisotopes with short half-life, less than two hours. The production and selling of short half-life radioisotopes used to be monopoly of the Brazilian Government. In 2006, a Constitutional Amendment revoked the state monopoly due to the need for the use of short half-life radioisotopes in nuclear medicine centers very far from the government production facilities. The aim of this study is to describe the current status of short half-life radioisotopes production in Brazil and discuss some licensing process. In Brazil, as has been occurring worldwide, the number of nuclear medicine centers is increasing. Currently there are 123 services performing PET scans in Brazil. There are 14 cyclotrons operating in Brazil. The type of licensing process conducted in Brazil does not take into account the population density of each state, with a free competition model being adopted. Because of this there is a lot of equipment concentrated in the Southeast and no cyclotrons operating in the Northern part of the country. One of the biggest obstacles during the licensing process is the designation of qualified personnel as operation workers and radiation safety officers. The number of cyclotron accelerators and PET/CT equipment increased in recent years. However, a number of external factors such as the distance from the nuclear medicine centers, and qualified personnel have proved crucial for the economic viability of this type of facility. (author)
Glow plasma trigger for electron cyclotron resonance ion sources.
Vodopianov, A V; Golubev, S V; Izotov, I V; Nikolaev, A G; Oks, E M; Savkin, K P; Yushkov, G Yu
2010-02-01
Electron cyclotron resonance ion sources (ECRISs) are particularly useful for nuclear, atomic, and high energy physics, as unique high current generators of multicharged ion beams. Plasmas of gas discharges in an open magnetic trap heated by pulsed (100 micros and longer) high power (100 kW and higher) high-frequency (greater than 37.5 GHz) microwaves of gyrotrons is promising in the field of research in the development of electron cyclotron resonance sources for high charge state ion beams. Reaching high ion charge states requires a decrease in gas pressure in the magnetic trap, but this method leads to increases in time, in which the microwave discharge develops. The gas breakdown and microwave discharge duration becomes greater than or equal to the microwave pulse duration when the pressure is decreased. This makes reaching the critical plasma density initiate an electron cyclotron resonance (ECR) discharge during pulse of microwave gyrotron radiation with gas pressure lower than a certain threshold. In order to reduce losses of microwave power, it is necessary to shorten the time of development of the ECR discharge. For fast triggering of ECR discharge under low pressure in an ECRIS, we initially propose to fill the magnetic trap with the plasmas of auxiliary pulsed discharges in crossed ExB fields. The glow plasma trigger of ECR based on a Penning or magnetron discharge has made it possible not only to fill the trap with plasma with density of 10(12) cm(-3), required for a rapid increase in plasma density and finally for ECR discharge ignition, but also to initially heat the plasma electrons to T(e) approximately = 20 eV.
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 gauge invariant potentials
Energy Technology Data Exchange (ETDEWEB)
Gonzalez, J.J. (Valladolid Univ. (Spain). Dept. de Fisica Teorica); Negro, J. (Valladolid Univ. (Spain). Dept. de Fisica Teorica); Olmo, M.A. del (Valladolid Univ. (Spain). Dept. de Fisica Teorica)
1995-01-01
A global method characterizing the invariant connections on an abelian principal bundle under a group of transformations is applied in order to get gauge invariant electromagnetic (elm.) potentials in a systematic way. So, we have classified all the elm. gauge invariant potentials under the Poincare subgroups of dimensions 4, 5, and 6, up to conjugation. It is paid attention in particular to the situation where these subgroups do not act transitively on the space-time manifold. We have used the same procedure for some galilean subgroups to get nonrelativistic potentials and study the way they are related to their relativistic partners by means of contractions. Some conformal gauge invariant potentials have also been derived and considered when they are seen as consequence of an enlargement of the Poincare symmetries. (orig.)
Conductivity of a relativistic plasma
Energy Technology Data Exchange (ETDEWEB)
Braams, B.J.; Karney, C.F.F.
1989-03-01
The collision operator for a relativistic plasma is reformulated in terms of an expansion in spherical harmonics. This formulation is used to calculate the electrical conductivity. 13 refs., 1 fig., 1 tab.
Superposition as a Relativistic Filter
Ord, G. N.
2017-07-01
By associating a binary signal with the relativistic worldline of a particle, a binary form of the phase of non-relativistic wavefunctions is naturally produced by time dilation. An analog of superposition also appears as a Lorentz filtering process, removing paths that are relativistically inequivalent. In a model that includes a stochastic component, the free-particle Schrödinger equation emerges from a completely relativistic context in which its origin and function is known. The result establishes the fact that the phase of wavefunctions in Schrödinger's equation and the attendant superposition principle may both be considered remnants of time dilation. This strongly argues that quantum mechanics has its origins in special relativity.
Residual radioactivity at the Milan AVF cyclotron
Birattari, C.; Cantone, M. C.; Ferrari, A.; Silari, M.
1989-08-01
γ-ray spectrometry measurements have been carried out at the Cyclotron Laboratory at the Department of Physics of the University of Milan, to evaluate the levels of residual radioactivity after about one year from shut down. Measurements were performed inside the cyclotron and at several points in the accelerator vault and target room, as well as on specific components removed from the beam transport system, on samples of the concrete shields and on residues taken from the cyclotron vacuum chamber. The radionuclides identified and the values of specific activity and dose rate are reported. The results indicate that no particular hazard and waste disposal problems should be encountered at the time of the decommissioning of the facility.
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.
Su, Z.; Zhu, H.; Xiao, F.; Zheng, H.; Shen, C.; Wang, Y.; Wang, S.
2012-12-01
The electromagnetic ion cyclotron (EMIC) wave has been long suggested to be responsible for the rapid loss of radiation belt relativistic electrons. The test-particle simulations are performed to calculate the bounce-averaged pitch-angle advection and diffusion coefficients for parallel-propagating monochromatic EMIC waves. The comparison between test-particle (TP) and quasi-linear (QL) transport coefficients is further made to quantify the influence of nonlinear processes. For typical EMIC waves, four nonlinear physical processes, i.e., the boundary reflection effect, finite perturbation effect, phase bunching and phase trapping, are found to occur sequentially from small to large equatorial pitch angles. The pitch-angle averaged finite perturbation effect yields slight differences between the transport coefficients of TP and QL models. The boundary reflection effect and phase bunching produce an average reduction of >80% in the diffusion coefficients but a small change in the corresponding average advection coefficients, tending to lower the loss rate predicted by QL theory. In contrast, the phase trapping causes continuous negative advection toward the loss cone and a minor change in the corresponding diffusion coefficients, tending to increase the loss rate predicted by QL theory. For small amplitude EMIC waves, the transport coefficients grow linearly with the square of wave amplitude. As the amplitude increases, the boundary reflection effect, phase bunching and phase trapping start to occur. Consequently, the TP advection coefficients deviate from the linear growth with the square of wave amplitude, and the TP diffusion coefficients become saturated with the amplitude approaching 1nT or above. The current results suggest that these nonlinear processes can cause significant deviation of transport coefficients from the prediction of QL theory, which should be taken into account in the future simulations of radiation belt dynamics driven by the EMIC waves.
Relativistic runaway breakdown in low-frequency radio
DEFF Research Database (Denmark)
Fullekrug, M.; Roussel-Dupre, R.; Symbalisty, E.M.D.
2011-01-01
The electromagnetic radiation emitted by an electron avalanche beam resulting from relativistic runaway breakdown within the Earth's atmosphere is investigated. It is found from theoretical modeling with a computer simulation that the electron beam emits electromagnetic radiation which...... at a distance of similar to 550 km. The measured broadband pulses occur similar to 4-9 ms after the sprite-producing lightning discharge, they exhibit electromagnetic radiation which mainly spans the frequency range from similar to 50 to 350 kHz, and they exhibit complex waveforms without the typical...
Relativistic multiwave Cerenkov generator
Bugaev, S. P.; Kanavets, V. I.; Klimov, A. I.; Koshelev, V. I.; Cherepenin, V. A.
1983-11-01
The design and operation of a multiwave Cerenkov generator using a relativistic electron beam are reported. The device comprises a 3-cm-radius tubular graphite cathode fed with a 1-microsec 1-2.5-MW pulse from a Marx generator; a 5.6-cm-radius anode; an increasing 14-32-kG magnetic field; a 3.4-cm-aperture-radius graphite collimating iris; a stainless-steel semitoroidal-iris-loaded slow-wave structure of maximum length 48.6 cm, inside radius 4.2 cm, iris aperture radius 3.0 cm, iris minor radius 3 mm, and period 1.5 cm; a stainless-steel cone collector; and a vacuum-tight 60-cm-radius window. At 2.5 MV and 21 kG, output power at wavelength 3.15 + or - 0.1 cm is measured as about 5 GW, with baseline pulse length 30-50 nsec and efficiency up to about 10 percent.
Relativistic Electron Vortices.
Barnett, Stephen M
2017-03-17
The desire to push recent experiments on electron vortices to higher energies leads to some theoretical difficulties. In particular the simple and very successful picture of phase vortices of vortex charge ℓ associated with ℓℏ units of orbital angular momentum per electron is challenged by the facts that (i) the spin and orbital angular momentum are not separately conserved for a Dirac electron, which suggests that the existence of a spin-orbit coupling will complicate matters, and (ii) that the velocity of a Dirac electron is not simply the gradient of a phase as it is in the Schrödinger theory suggesting that, perhaps, electron vortices might not exist at a fundamental level. We resolve these difficulties by showing that electron vortices do indeed exist in the relativistic theory and show that the charge of such a vortex is simply related to a conserved orbital part of the total angular momentum, closely related to the familiar situation for the orbital angular momentum of a photon.
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 electron precipitation as seen by NOAA POES
Yahnin, A. G.; Yahnina, T. A.; Semenova, N. V.; Gvozdevsky, B. B.; Pashin, A. B.
2016-09-01
We performed a survey of relativistic electron precipitation (REP) events revealed by the Medium Energy Proton and Electron Detector instrument on board NOAA Polar-orbiting Operational Environmental Satellites during a 38 day interval. We have divided the observed REP events into three groups with respect to the simultaneous observations of energetic (>30 keV) electron and proton precipitation. The first group consists of REP enhancements forming the isotropy zone at the poleward edge of trapped relativistic electron fluxes. These REP events are observed on the nightside, and they are, apparently, produced by isotropization process related to nonadiabatic motion of particles in the stretched magnetic field. The second group are the REP events related to simultaneous enhancements of energetic >30-300 keV electrons. These events have a wider magnetic local time range of occurrence with a maximum in the premidnight sector. They can be related to the interaction of electrons with waves whose possible nature is briefly discussed on the basis of comparison with the cold plasma density in the conjugated region of the equatorial plane. The third group consists of the REP events correlated with the burst-like precipitation of >30-keV protons within an anisotropy zone, where the trapped flux dominates. These events are found in the dusk sector in association with enhanced cold plasma density in the conjugate equatorial magnetosphere. As is known, proton bursts within the anisotropy zone indicate the location of the electromagnetic ion cyclotron (EMIC) wave source. Such REP events can be due to scattering of the relativistic electrons by EMIC waves. However, we noted that some of these REP events are associated with precipitation of energetic electrons with low-energy cutoff below 100 keV. We suggest that in such cases the electrons within a wide energy range are precipitated by other waves (probably, by plasmaspheric hiss).
Graphical user interface for yield and dose estimations for cyclotron-produced technetium.
Hou, X; Vuckovic, M; Buckley, K; Bénard, F; Schaffer, P; Ruth, T; Celler, A
2014-07-07
The cyclotron-based (100)Mo(p,2n)(99m)Tc reaction has been proposed as an alternative method for solving the shortage of (99m)Tc. With this production method, however, even if highly enriched molybdenum is used, various radioactive and stable isotopes will be produced simultaneously with (99m)Tc. In order to optimize reaction parameters and estimate potential patient doses from radiotracers labeled with cyclotron produced (99m)Tc, the yields for all reaction products must be estimated. Such calculations, however, are extremely complex and time consuming. Therefore, the objective of this study was to design a graphical user interface (GUI) that would automate these calculations, facilitate analysis of the experimental data, and predict dosimetry. The resulting GUI, named Cyclotron production Yields and Dosimetry (CYD), is based on Matlab®. It has three parts providing (a) reaction yield calculations, (b) predictions of gamma emissions and (c) dosimetry estimations. The paper presents the outline of the GUI, lists the parameters that must be provided by the user, discusses the details of calculations and provides examples of the results. Our initial experience shows that the proposed GUI allows the user to very efficiently calculate the yields of reaction products and analyze gamma spectroscopy data. However, it is expected that the main advantage of this GUI will be at the later clinical stage when entering reaction parameters will allow the user to predict production yields and estimate radiation doses to patients for each particular cyclotron run.
Graphical user interface for yield and dose estimations for cyclotron-produced technetium
Hou, X.; Vuckovic, M.; Buckley, K.; Bénard, F.; Schaffer, P.; Ruth, T.; Celler, A.
2014-07-01
The cyclotron-based 100Mo(p,2n)99mTc reaction has been proposed as an alternative method for solving the shortage of 99mTc. With this production method, however, even if highly enriched molybdenum is used, various radioactive and stable isotopes will be produced simultaneously with 99mTc. In order to optimize reaction parameters and estimate potential patient doses from radiotracers labeled with cyclotron produced 99mTc, the yields for all reaction products must be estimated. Such calculations, however, are extremely complex and time consuming. Therefore, the objective of this study was to design a graphical user interface (GUI) that would automate these calculations, facilitate analysis of the experimental data, and predict dosimetry. The resulting GUI, named Cyclotron production Yields and Dosimetry (CYD), is based on Matlab®. It has three parts providing (a) reaction yield calculations, (b) predictions of gamma emissions and (c) dosimetry estimations. The paper presents the outline of the GUI, lists the parameters that must be provided by the user, discusses the details of calculations and provides examples of the results. Our initial experience shows that the proposed GUI allows the user to very efficiently calculate the yields of reaction products and analyze gamma spectroscopy data. However, it is expected that the main advantage of this GUI will be at the later clinical stage when entering reaction parameters will allow the user to predict production yields and estimate radiation doses to patients for each particular cyclotron run.
Low current performance of the Bern medical cyclotron down to the pA range
Auger, M.; Braccini, S.; Ereditato, A.; Nesteruk, K. P.; Scampoli, P.
2015-09-01
A medical cyclotron accelerating H- ions to 18 MeV is in operation at the Bern University Hospital (Inselspital). It is the commercial IBA 18/18 cyclotron equipped with a specifically conceived 6 m long external beam line ending in a separate bunker. This feature is unique for a hospital-based facility and makes it possible to conduct routine radioisotope production for PET diagnostics in parallel with multidisciplinary research activities, among which are novel particle detectors, radiation biophysics, radioprotection, radiochemistry and radiopharmacy developments. Several of these activities, such as radiobiology experiments for example, require low current beams down to the pA range, while medical cyclotrons are designed for high current operation above 10 μA. In this paper, we present the first results on the low current performance of a PET medical cyclotron obtained by ion source, radio-frequency and main coil tuning. With this method, stable beam currents down to (1.5+/- 0.5 ) pA were obtained and measured with a high-sensitivity Faraday cup located at the end of the beam transport line.
Sarma phase in relativistic and non-relativistic systems
Directory of Open Access Journals (Sweden)
I. Boettcher
2015-03-01
Full Text Available We investigate the stability of the Sarma phase in two-component fermion systems in three spatial dimensions. For this purpose we compare strongly-correlated systems with either relativistic or non-relativistic dispersion relation: relativistic quarks and mesons at finite isospin density and spin-imbalanced ultracold Fermi gases. Using a Functional Renormalization Group approach, we resolve fluctuation effects onto the corresponding phase diagrams beyond the mean-field approximation. We find that fluctuations induce a second-order phase transition at zero temperature, and thus a Sarma phase, in the relativistic setup for large isospin chemical potential. This motivates the investigation of the cold atoms setup with comparable mean-field phase structure, where the Sarma phase could then be realized in experiment. However, for the non-relativistic system we find the stability region of the Sarma phase to be smaller than the one predicted from mean-field theory. It is limited to the BEC side of the phase diagram, and the unitary Fermi gas does not support a Sarma phase at zero temperature. Finally, we propose an ultracold quantum gas with four fermion species that has a good chance to realize a zero-temperature Sarma phase.
Spinelli, A. E.; Boschi, F.; Calandrino, R.
2017-05-01
Radioisotopes production for PET radiopharmaceuticals is performed using cyclotrons resulting in radio activation of different cyclotron components. It is thus necessary to measure the level of radiation exposure and, if possible, to image the areas where most of the radiations are emitted in particular during maintenance or decommissioning procedures. In this work we present a novel optical imaging approach using Cerenkov luminescence imaging (CLI) and radioluminescence imaging (RLI). CLI was performed by placing a glass Cerenkov radiator on a target window (Havar foils) and RLI data were obtained by covering the Havar foils with an intensifying screen. CLI or RLI were acquired using a small animal optical imaging system used in bioluminescence mode without the use of any optical filters. The analysis of the normalized radiance line profiles of both CLI and RLI images showed a similar pattern, however the absolute radiance of the RLI signal is several order of magnitude higher with respect to CLI. We conclude that optical imaging with CLI and RLI can be considered a novel method to detect and image activation areas in irradiated samples from a medical cyclotron.
Proton radiation therapy in Canada
Energy Technology Data Exchange (ETDEWEB)
Grein, E.; Duzenli, C.; Pickles, T.; Ma, R.; Paton, K.; Kwa, W.; Harrison, R.; Blackmore, E. [BC Cancer Agency, Vancouver, British Columbia (Canada); TRIUMF, Vancouver, British Columbia (Canada)
2002-04-01
The development, commissioning, and implementation of the first Canadian Proton Radiation Therapy facility at TRIUMF in British Columbia is described. This was a collaborative project by the cyclotron physicists and staff at TRIUMF, the medical physicists and radiation oncologists of the Cancer Agency and the ocular oncology physicians of the Eye Care Center at Vancouver Hospital. (author)
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 =
Microwave power coupling with electron cyclotron resonance ...
Indian Academy of Sciences (India)
Electron cyclotron resonance (ECR) plasma was produced at 2.45 GHz using 200 – 750 W microwave power. The plasma was produced from argon gas at a pressure of 2 × 10−4 mbar. Three water-cooled solenoid coils were used to satisfy the ECR resonant conditions inside the plasma chamber. The basic parameters of ...
The Data Cyclotron query processing scheme
Goncalves, R.; Kersten, M.
2011-01-01
A grand challenge of distributed query processing is to devise a self-organizing architecture which exploits all hardware resources optimally to manage the database hot set, minimize query response time, and maximize throughput without single point global coordination. The Data Cyclotron
The Data Cyclotron query processing scheme.
R.A. Goncalves (Romulo); M.L. Kersten (Martin)
2011-01-01
htmlabstractA grand challenge of distributed query processing is to devise a self-organizing architecture which exploits all hardware resources optimally to manage the database hot set, minimize query response time, and maximize throughput without single point global coordination. The Data Cyclotron
Electron-cyclotron-resonance ion sources (review)
Energy Technology Data Exchange (ETDEWEB)
Golovanivskii, K.S.; Dougar-Jabon, V.D. [People`s Friendship Univ., Moscow (Russian Federation)
1992-01-01
The physical principles are described and a brief survey of the present state is given of ion sources based on electron-cyclotron heating of plasma in a mirror trap. The characteristics of ECR sources of positive and negative ions used chiefly in accelerator technology are presented. 20 refs., 10 figs., 3 tabs.
CERN PhotoLab
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.
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.
Resonant cyclotron scattering in magnetars' emission
Rea, N.; Zane, S.; Turolla, R.; Lyutikov, M.; Götz, D.
2008-01-01
We present a systematic fit of a model of resonant cyclotron scattering (RCS) to the X-ray data of 10 magnetars, including canonical and transient anomalous X-ray pulsars (AXPs) and soft gamma repeaters (SGRs). In this scenario, nonthermal magnetar spectra in the soft X-rays (i.e., below ~10 keV)
Ion cyclotron resonance heating system on Aditya
Indian Academy of Sciences (India)
R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22
1Institute for Plasma Research, Bhat, Gandhinagar 382 428, India. 2Variable Electron Cyclotron .... Requirements for RF generators for fusion research include high power, long pulse duration and reliability. ... Output of pre-driver (triode 3CX5000A7) grounded grid amplifier is made tunable within. 20 to 47 MHz by using a ...
Program Complex For Cyclotron Beam Dynamic Simulations
Glazov, A A; Karamysheva, G A; Lisenkova, O E
2004-01-01
The program complex in MATLAB intended for particle dynamic simulations is described. Programming in an easy-to-use environment permits creation of models in a short space of time. Advanced graphical tools of MATLAB give good visualization features to created models. The beam dynamic modelling results by the example of two different cyclotron designs are presented.
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...
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.
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.
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.
The relativistic feedback discharge model of terrestrial gamma ray flashes
Dwyer, Joseph R.
2012-02-01
As thunderclouds charge, the large-scale fields may approach the relativistic feedback threshold, above which the production of relativistic runaway electron avalanches becomes self-sustaining through the generation of backward propagating runaway positrons and backscattered X-rays. Positive intracloud (IC) lightning may force the large-scale electric fields inside thunderclouds above the relativistic feedback threshold, causing the number of runaway electrons, and the resulting X-ray and gamma ray emission, to grow exponentially, producing very large fluxes of energetic radiation. As the flux of runaway electrons increases, ionization eventually causes the electric field to discharge, bringing the field below the relativistic feedback threshold again and reducing the flux of runaway electrons. These processes are investigated with a new model that includes the production, propagation, diffusion, and avalanche multiplication of runaway electrons; the production and propagation of X-rays and gamma rays; and the production, propagation, and annihilation of runaway positrons. In this model, referred to as the relativistic feedback discharge model, the large-scale electric fields are calculated self-consistently from the charge motion of the drifting low-energy electrons and ions, produced from the ionization of air by the runaway electrons, including two- and three-body attachment and recombination. Simulation results show that when relativistic feedback is considered, bright gamma ray flashes are a natural consequence of upward +IC lightning propagating in large-scale thundercloud fields. Furthermore, these flashes have the same time structures, including both single and multiple pulses, intensities, angular distributions, current moments, and energy spectra as terrestrial gamma ray flashes, and produce large current moments that should be observable in radio waves.
EBCO Technologies TR Cyclotrons, Dynamics, Equipment, and Applications
Johnson, R. R.; Erdman, K. L.; Gyles, Wm.; Burbee, J.; VanLier, E.; Kovacs, M.; Perron, F.
2003-08-01
The Ebco Technologies TR cyclotrons have a common parent in the 500 MeV negative ion cyclotron at TRIUMF in Vancouver. As such, the TR cyclotrons have features that can be adapted for specific application. The cyclotron design is modularized into ion source and injection system, central region and then extraction. The cyclotron ion source is configured for cyclotron beam currents ranging from 50 microAmps to 2 milliAmps. The injection line can be operated in either continuous (CW) or in pulsed mode. The center region of the cyclotron is configured to match the ion source configuration. The extracted beams are directed either to a local target station or to beam lines and thence to target stations. There has been development both in solid, liquid and gas targets. There has been development in radioisotope handling techniques, target material recovery and radiochemical synthesis.
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.
Measuring main-ion temperatures in ASDEX upgrade using scattering of ECRH radiation
DEFF Research Database (Denmark)
Pedersen, Morten Stejner; Nielsen, Stefan Kragh; Jacobsen, Asger Schou
2016-01-01
We demonstrate that collective Thomson scattering of millimeter wave electron cyclotron resonance heating radiation can be used for measurements of the main-ion temperature in the ASDEX Upgrade tokamak.......We demonstrate that collective Thomson scattering of millimeter wave electron cyclotron resonance heating radiation can be used for measurements of the main-ion temperature in the ASDEX Upgrade tokamak....
Relativistic Quasiparticle Random Phase Approximation in Deformed Nuclei
Pena Arteaga, Daniel
2008-01-01
Covariant density functional theory is used to study the influence of electromagnetic radiation on deformed superfluid nuclei. The relativistic Hartree-Bogoliubov equations and the resulting diagonalization problem of the quasiparticle random phase approximation are solved for axially symmetric systems in a fully self-consistent way by a newly developed parallel code. Three different kinds of high precision energy functionals are investigated and special care is taken for the decoupling of th...
Electron injection by relativistic protons in active galactic nuclei
Sikora, Marek; Kirk, John G.; Begelman, Mitchell C.; Schneider, Peter
1987-01-01
It is shown that protons with Lorentz factors larger than about 1,000,000 are cooled very rapidly by collisions with soft photons in the environment of an AGN. If the energy distribution of accelerated protons is sufficiently flat, then most of the energy contained in relativistic protons will be transformed to pairs, and then to radiation. Under these conditions, proton cooling due to p-gamma interactions is much more important than energy losses due to inelastic proton-proton collisions.
Schiller, Quintin; Mahendrakumar, Abhishek
2010-01-01
The Relativistic Electron and Proton Telescope integrated l little experiment (REPTile) is a solid-state Particle detector designed to measure solar energetic protons and relativistic electrons in Earth's outer radiation belt. These particles pose a radiation threat to both spacecraft and astronauts in space, and developing a better understanding of these particles has been identified as a critical area of research by NASA's Living with a Star program. REPTile has been designed specifically t...
Modeling of electron cyclotron resonance acceleration in a stationary inhomogeneous magnetic field
Directory of Open Access Journals (Sweden)
Valeri D. Dougar-Jabon
2008-04-01
Full Text Available In this paper, the cyclotron autoresonance acceleration of electrons in a stationary inhomogeneous magnetic field is studied. The trajectory and energy of electrons are found through a numerical solution of the relativistic Newton-Lorentz equation by a finite difference method. The electrons move along a TE_{112} cylinder cavity in a steady-state magnetic field whose axis coincides with the cavity axis. The magnetic field profile is such that it keeps the phase difference between the electric microwave field and the electron velocity vector within the acceleration phase band. The microwaves amplitude of 6 kV/cm is used for numerical calculations. It is shown that an electron with an initial longitudinal energy of 8 keV can be accelerated up to 260 keV by 2.45 GHz microwaves at a distance of 17 cm.
Energy Technology Data Exchange (ETDEWEB)
Castor, J I
2003-10-16
to distinguish hydrogen atoms from helium atoms, for instance. There are all just components of a mixed fluid in this case. So why do we have a special subject called ''radiation hydrodynamics'', when photons are just one of the many kinds of particles that comprise our fluid? The reason is that photons couple rather weakly to the atoms, ions and electrons, much more weakly than those particles couple with each other. Nor is the matter-radiation coupling negligible in many problems, since the star or nebula may be millions of mean free paths in extent. Radiation hydrodynamics exists as a discipline to treat those problems for which the energy and momentum coupling terms between matter and radiation are important, and for which, since the photon mean free path is neither extremely large nor extremely small compared with the size of the system, the radiation field is not very easy to calculate. In the theoretical development of this subject, many of the relations are presented in a form that is described as approximate, and perhaps accurate only to order of {nu}/c. This makes the discussion cumbersome. Why are we required to do this? It is because we are using Newtonian mechanics to treat our fluid, yet its photon component is intrinsically relativistic; the particles travel at the speed of light. There is a perfectly consistent relativistic kinetic theory, and a corresponding relativistic theory of fluid mechanics, which is perfectly suited to describing the photon gas. But it is cumbersome to use this for the fluid in general, and we prefer to avoid it for cases in which the flow velocity satisfies {nu} << c. The price we pay is to spend extra effort making sure that the source-sink terms relating to our relativistic gas component are included in the equations of motion in a form that preserves overall conservation of energy and momentum, something that would be automatic if the relativistic equations were used throughout.
Use of maze in cyclotron hoppers; Utilizacao de labirinto em bunker de ciclotron
Energy Technology Data Exchange (ETDEWEB)
Fernandes, Fernando A.; Alves, Juliano S.; Fochesatto, Cintia; Cerioli, Luciane; Borges, Joao Alfredo; Gonzalez, Delfin; Silva, Daniel C., E-mail: fernandofernandes@biofarmaco.com.br [Delfin Farmacos e Derivados (Biofarmaco Marcadores Moleculares), Lauro de Freitas, BA (Brazil)
2013-07-01
Introduction: the increasing number of cyclotrons in Brazil due to constitutional amendment 49 /06 that enabled the production of radiopharmaceuticals with a short half - life by private companies. The radionuclides used for PET - CT require production centers near or within the diagnostic centers. In order to minimize maintenance and operating risks, gaining efficiency, our facility was the first in Brazil to use the access to a cyclotron bunker via maze, rather than armored door stopper type. Materials: the design calculations were based on the Monte Carlo method (MCNP5 - Monte Carlo N-Particletransportcode version 5). At the ends of the labyrinth are installed a door of polyethylene, for thermalization of neutrons, and other of wood for limiting access. Both legs of the maze have wall thickness of 100cm. In inspection Brazilian CNEN realize measures of dose rate for neutrons and gamma 9 points: 7 around the bunker, 1 over the bunker and 1 in the exhaust with the cyclotron operating with maximum load, double beam of 50uA for 2 hours. After commissioning were carried out around the bunker, the following measures: cumulative dose in three months with dosimeters for neutron rate dose with a gas proportional detector type filled with {sup 3}He and polyethylene neutron moderator and dose rate with a Geiger - Mueller detector for gamma radiation. Readings with neutron detectors were classified as background radiation and dose rates were always below the limits established in standard EN 3.01, and the calculation of the predicted regardless of the intensity of irradiation inside the bunker. Conclusion: the use of labyrinths as a way to access the bunkers cyclotron has been shown to be effective as the radiation shielding and efficient by allowing quick and easy access, virtually eliminating the maintenance.
Properties of relativistically rotating quark stars
Zhou, Enping
2017-06-01
In this work, quasi-equilibrium models of rapidly rotating triaxially deformed quark stars are computed in general relativistic gravity, assuming a conformally flat spatial geometry (Isenberg-Wilson-Mathews formulation) and a polynomial equation of state. Especially, since we are using a full 3-D numerical relativity initial data code, we are able to consider the triaxially deformed rotating quark stars at very high spins. Such triaxially deformed stars are possible gravitational radiation sources detectable by ground based gravitational wave observatories. Additionally, the bifurcation from axisymmetric rotating sequence to triaxially rotating sequence hints a more realistic spin up limit for rotating compact stars compared with the mass-shedding limit. With future observations such as sub-millisecond pulsars, we could possibly distinguish between equation of states of compact stars, thus better understanding strong interaction in the low energy regime.
Relativistic runaway breakdown in low-frequency radio
Füllekrug, Martin; Roussel-Dupré, Robert; Symbalisty, Eugene M. D.; Chanrion, Olivier; Odzimek, Anna; van der Velde, Oscar; Neubert, Torsten
2010-01-01
The electromagnetic radiation emitted by an electron avalanche beam resulting from relativistic runaway breakdown within the Earth's atmosphere is investigated. It is found from theoretical modeling with a computer simulation that the electron beam emits electromagnetic radiation which is characterized by consecutive broadband pulses in the low-frequency radio range from ˜10 to 300 kHz at a distance of ˜800 km. Experimental evidence for the existence of consecutive broadband pulses is provided by low-frequency radio observations of sprite-producing lightning discharges at a distance of ˜550 km. The measured broadband pulses occur ˜4-9 ms after the sprite-producing lightning discharge, they exhibit electromagnetic radiation which mainly spans the frequency range from ˜50 to 350 kHz, and they exhibit complex waveforms without the typical ionospheric reflection of the first hop sky wave. Two consecutive pulses occur ˜4.5 ms and ˜3 ms after the causative lightning discharge and coincide with the sprite luminosity. It is concluded that relativistic runaway breakdown within the Earth's atmosphere can emit broadband electromagnetic pulses and possibly generates sprites. The source location of the broadband pulses can be determined with an interferometric network of wideband low-frequency radio receivers to lend further experimental support to the relativistic runaway breakdown theory.
Relativistic quantum mechanics wave equations
Greiner, Walter
1990-01-01
Relativistic Quantum Mechanics - Wave Equations concentrates mainly on the wave equations for spin-0 and spin-12 particles Chapter 1 deals with the Klein-Gordon equation and its properties and applications The chapters that follow introduce the Dirac equation, investigate its covariance properties and present various approaches to obtaining solutions Numerous applications are discussed in detail, including the two-center Dirac equation, hole theory, CPT symmetry, Klein's paradox, and relativistic symmetry principles Chapter 15 presents the relativistic wave equations for higher spin (Proca, Rarita-Schwinger, and Bargmann-Wigner) The extensive presentation of the mathematical tools and the 62 worked examples and problems make this a unique text for an advanced quantum mechanics course
Non-Relativistic Superstring Theories
Energy Technology Data Exchange (ETDEWEB)
Kim, Bom Soo
2007-12-14
We construct a supersymmetric version of the 'critical' non-relativistic bosonic string theory [1] with its manifest global symmetry. We introduce the anticommuting bc CFT which is the super partner of the {beta}{gamma} CFT. The conformal weights of the b and c fields are both 1/2. The action of the fermionic sector can be transformed into that of the relativistic superstring theory. We explicitly quantize the theory with manifest SO(8) symmetry and find that the spectrum is similar to that of Type IIB superstring theory. There is one notable difference: the fermions are non-chiral. We further consider 'noncritical' generalizations of the supersymmetric theory using the superspace formulation. There is an infinite range of possible string theories similar to the supercritical string theories. We comment on the connection between the critical non-relativistic string theory and the lightlike Linear Dilaton theory.
Ogunjobi, O.; Sivakumar, V.; Mtumela, Z.
2017-06-01
Energetic electrons are trapped in the Earth's radiation belts which occupy a toroidal region between 3 and 7 \\hbox {R}E above the Earth's surface. Rapid loss of electrons from the radiation belts is known as dropouts. The source and loss mechanisms regulating the radiation belts population are not yet understood entirely, particularly during geomagnetic storm times. Nevertheless, the dominant loss mechanism may require an event based study to be better observed. Utilizing multiple data sources from the year 1997-2007, this study identifies radiation belt electron dropouts which are ultimately triggered when solar wind stream interfaces (SI) arrived at Earth, or when magnetic clouds (MC) arrived. Using superposed epoch analysis (SEA) technique, a synthesis of multiple observations is performed to reveal loss mechanism which might, perhaps, be a major contributor to radiation belt losses under SI and MC driven storms. Results show an abrupt slower decaying precipitation of electron peak (about 3000 counts/sec) on SI arrival within 5.05 < L < 6.05, which persist till 0.5 day before gradual recovery. This pattern is interpreted as an indication of depleted electrons from bounce lost cone via precipitating mechanism known as relativistic electron microburst. On the other hand, MC shows a pancake precipitating peak extending to lower L (Plasmapause); indicating a combination of electron cyclotron harmonic (ECH) and whistler mode waves as the contributing mechanisms.
Relativistic EOS for supernova simulations
Directory of Open Access Journals (Sweden)
Shen H.
2014-03-01
Full Text Available We study the relativistic equation of state (EOS of dense matter covering a wide range of temperature, proton fraction, and baryon density for the use of supernova simulations. This work is based on the relativistic mean-field theory (RMF and the Thomas-Fermi approximation. The Thomas-Fermi approximation in combination with assumed nucleon distribution functions and a free energy minimization is adopted to describe the non-uniform matter, which is composed of a lattice of heavy nuclei. We treat the uniform matter and non-uniform matter consistently using the same RMF theory. We compare the EOS tables in detail.
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.
Transport models for relativistic heavy-ion collisions at Relativistic ...
Indian Academy of Sciences (India)
Abstract. We review the transport models that are widely used to study the properties of the quark-gluon plasma formed in relativistic heavy-ion collisions at RHIC and LHC. We show that transport model analysis of two important and complementary observables, the anisotropic flow of bulk hadrons and suppression of ...
Modeling terrestrial gamma ray flashes produced by relativistic feedback discharges
Liu, Ningyu; Dwyer, Joseph R.
2013-05-01
This paper reports a modeling study of terrestrial gamma ray flashes (TGFs) produced by relativistic feedback discharges. Terrestrial gamma ray flashes are intense energetic radiation originating from the Earth's atmosphere that has been observed by spacecraft. They are produced by bremsstrahlung interactions of energetic electrons, known as runaway electrons, with air atoms. An efficient physical mechanism for producing large fluxes of the runaway electrons to make the TGFs is the relativistic feedback discharge, where seed runaway electrons are generated by positrons and X-rays, products of the discharge itself. Once the relativistic feedback discharge becomes self-sustaining, an exponentially increasing number of relativistic electron avalanches propagate through the same high-field region inside the thundercloud until the electric field is partially discharged by the ionization created by the discharge. The modeling results indicate that the durations of the TGF pulses produced by the relativistic feedback discharge vary from tens of microseconds to several milliseconds, encompassing all durations of the TGFs observed so far. In addition, when a sufficiently large potential difference is available in thunderclouds, a self-propagating discharge known as the relativistic feedback streamer can be formed, which propagates like a conventional positive streamer. For the relativistic feedback streamer, the positive feedback mechanism of runaway electron production by the positrons and X-rays plays a similar role as the photoionization for the conventional positive streamer. The simulation results of the relativistic feedback streamer show that a sequence of TGF pulses with varying durations can be produced by the streamer. The relativistic streamer may initially propagate with a pulsed manner and turn into a continuous propagation mode at a later stage. Milliseconds long TGF pulses can be produced by the feedback streamer during its continuous propagation. However
Strong-coupling diffusion in relativistic systems
Indian Academy of Sciences (India)
Relativistic heavy-ion collisions; fluctuation phenomena; relativistic diffusion model; net-proton rapidly ... cients on the available relativistic energy, results at 40 A•GeV/c are obtained. Extrapolat- ing to higher ... proached for times t ^τs larger than the time τs that is characteristic for strong coupling. – when all secondary ...
Energy Technology Data Exchange (ETDEWEB)
Videira, Heber S.; Burkhardt, Guilherme M.; Santos, Ronielly S., E-mail: heber@cyclopet.com.br [Cyclopet Radiofarmacos Ltda., Curitiba, PR (Brazil); Passaro, Bruno M.; Gonzalez, Julia A.; Santos, Josefina; Guimaraes, Maria I.C.C. [Universidade de Sao Paulo (HCFMRP/USP), Sao Paulo, SP (Brazil). Faculdade de Medicina. Hospital das Clinicas; Lenzi, Marcelo K. [Universidade Federal do Parana (UFPR), Curitina (Brazil). Programa de Pos-Graduacao em Engenharia Quimica
2013-04-15
The technological advances in positron emission tomography (PET) in conventional clinic imaging have led to a steady increase in the number of cyclotrons worldwide. Most of these cyclotrons are being used to produce {sup 18}F-FDG, either for themselves as for the distribution to other centers that have PET. For there to be safety in radiological facilities, the cyclotron intended for medical purposes can be classified in category I and category II, ie, self-shielded or non-shielded (bunker). Therefore, the aim of this work is to verify the effectiveness of borated water shield built for a cyclotron accelerator-type Self-shielded PETtrace 860. Mixtures of water borated occurred in accordance with the manufacturer’s specifications, as well as the results of the radiometric survey in the vicinity of the self-shielding of the cyclotron in the conditions established by the manufacturer showed that radiation levels were below the limits. (author)
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.
Future relativistic heavy ion experiments
Energy Technology Data Exchange (ETDEWEB)
Pugh, H.G.
1980-12-01
Equations of state for nuclear matter and ongoing experimental studies are discussed. Relativistic heavy ion physics is the only opportunity to study in the laboratory the properties of extended multiquark systems under conditions such that quarks might run together into new arrangements previously unobserved. Several lines of further study are mentioned. (GHT)
Revisiting non-relativistic limits
Energy Technology Data Exchange (ETDEWEB)
Jensen, Kristan [C.N. Yang Institute for Theoretical Physics, SUNY Stony Brook,Stony Brook, NY 11794-3840 (United States); Karch, Andreas [Department of Physics, University of Washington,Seattle, WA 98195 (United States)
2015-04-28
We show that the full spurionic symmetry of Galilean-invariant field theories can be deduced when those theories are the limits of relativistic parents. Under the limit, the non-relativistic daughter couples to Newton-Cartan geometry together with all of the symmetries advocated in previous work, including the recently revived Milne boosts. Our limit is a covariant version of the usual one, where we start with a gapped relativistic theory with a conserved charge, turn on a chemical potential equal to the rest mass of the lightest charged state, and then zoom in to the low energy sector. This procedure gives a simple physical interpretation for the Milne boosts. Our methods even apply when there is a magnetic moment, which is known to modify the non-relativistic symmetry transformations. We focus on two examples. Free scalars are used to demonstrate the basic procedure, whereas hydrodynamics is used in order to exhibit the power of this approach in a fully dynamical setting, correcting several inaccuracies in the existing literature.
Van Allen Probes observations of oxygen cyclotron harmonic waves in the inner magnetosphere
Usanova, M.; Malaspina, D.; Jaynes, A. N.; Bruder, R.; Mann, I. R.; Wygant, J. R.; Ergun, R.
2016-12-01
Waves with frequencies in the vicinity of the oxygen cyclotron frequency and its harmonics have been regularly observed on the Van Allen Probes satellites during geomagnetic storms. We focus on properties of these waves and present events from the main phase of two storms on November 1, 2012 and March 17, 2013 and associated dropouts of few MeV electron fluxes. They are electromagnetic, in the frequency range 0.5 - several Hz, and amplitude 0.1- a few nT in magnetic and 0.1- a few mV/m in electric field, with both the wave velocity and the Poynting vector directed almost parallel to the background magnetic field. These properties are very similar to those of electromagnetic ion cyclotron (EMIC) waves, which are believed to contribute to loss of ring current ions and radiation belt electrons and therefore can be also important for inner magnetosphere dynamics.
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.
Relativistic quantum mechanics an introduction to relativistic quantum fields
Maiani, Luciano
2016-01-01
Written by two of the world's leading experts on particle physics and the standard model - including an award-winning former Director General of CERN - this textbook provides a completely up-to-date account of relativistic quantum mechanics and quantum field theory. It describes the formal and phenomenological aspects of the standard model of particle physics, and is suitable for advanced undergraduate and graduate students studying both theoretical and experimental physics.
Nonlinear collisionless damping of Weibel turbulence in relativistic blast waves
Lemoine, Martin
2015-01-01
The Weibel/filamentation instability is known to play a key role in the physics of weakly magnetized collisionless shock waves. From the point of view of high energy astrophysics, this instability also plays a crucial role because its development in the shock precursor populates the downstream with a small-scale magneto-static turbulence which shapes the acceleration and radiative processes of suprathermal particles. The present work discusses the physics of the dissipation of this Weibel-generated turbulence downstream of relativistic collisionless shock waves. It calculates explicitly the first-order nonlinear terms associated to the diffusive nature of the particle trajectories. These corrections are found to systematically increase the damping rate, assuming that the scattering length remains larger than the coherence length of the magnetic fluctuations. The relevance of such corrections is discussed in a broader astrophysical perspective, in particular regarding the physics of the external relativistic shock wave of a gamma-ray burst.
Channeling of ultra-relativistic positrons in bent diamond crystals
Directory of Open Access Journals (Sweden)
R.G. Polozkov
2015-06-01
Full Text Available Results of numerical simulations of channeling of ultra-relativistic positrons are reported for straight and uniformly bent diamond crystals. The projectile trajectories in a crystal are computed using a newly developed module of the MBN Explorer package which simulates classical trajectories in a crystalline medium by integrating the relativistic equations of motion with account for the interaction between the projectile and the crystal atoms. The Monte Carlo method is employed to sample the incoming positrons and to account for thermal vibrations of the crystal atoms. The channeling parameters and emission spectra of incident positrons with a projecti le energy of 855 MeV along C(110 crystallographic planes are calculated for different bending radii of the crystal. Two features of the emission spectrum associated with positron oscillations in a channel and synchrotron radiation are studied as a function of crystal curvature.
Kinetic approach to relativistic dissipation
Gabbana, A.; Mendoza, M.; Succi, S.; Tripiccione, R.
2017-08-01
Despite a long record of intense effort, the basic mechanisms by which dissipation emerges from the microscopic dynamics of a relativistic fluid still elude complete understanding. In particular, several details must still be finalized in the pathway from kinetic theory to hydrodynamics mainly in the derivation of the values of the transport coefficients. In this paper, we approach the problem by matching data from lattice-kinetic simulations with analytical predictions. Our numerical results provide neat evidence in favor of the Chapman-Enskog [The Mathematical Theory of Non-Uniform Gases, 3rd ed. (Cambridge University Press, Cambridge, U.K., 1970)] procedure as suggested by recent theoretical analyses along with qualitative hints at the basic reasons why the Chapman-Enskog expansion might be better suited than Grad's method [Commun. Pure Appl. Math. 2, 331 (1949), 10.1002/cpa.3160020403] to capture the emergence of dissipative effects in relativistic fluids.
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.
Special vortex in relativistic hydrodynamics
Chupakhin, A. P.; Yanchenko, A. A.
2017-10-01
An exact solution of the Euler equations governing the flow of a compressible fluid in relativistic hydrodynamics is found and studied. It is a relativistic analogue of the Ovsyannikov vortex (special vortex) investigated earlier for classical gas dynamics. Solutions are partially invariant of Defect 1 and Rank 2 with respect to the rotation group. A theorem on the representation of the factor-system in the form of a union of a non-invariant subsystem for the function determining the deviation of the velocity vector from the meridian, and invariant subsystem for determination of thermodynamic parameters, the Lorentz factor and the radial velocity component is proved. Compatibility conditions for the overdetermined non-invariant subsystem are obtained. A stationary solution of this type is studied in detail. It is proved that its invariant subsystem reduces to an implicit differential equation. For this equation, the manifold of branching of solutions is investigated, and a set of singular points is found.
Towards a relativistic statistical theory
Kaniadakis, G.
2006-06-01
In special relativity the mathematical expressions, defining physical observables as the momentum, the energy etc. emerge as one parameter (light speed) continuous deformations of the corresponding ones of the classical physics. Here, we show that the special relativity imposes a proper one parameter continuous deformation also to the expression of the classical Boltzmann-Gibbs-Shannon entropy. The obtained relativistic entropy permits to construct a coherent and selfconsistent relativistic statistical theory [G. Kaniadakis, Phys. Rev. E 66 (2002) 056125; G. Kaniadakis, Phys. Rev. E 72 (2005) 036108], preserving the main features (maximum entropy principle, thermodynamic stability, Lesche stability, continuity, symmetry, expansivity, decisivity, etc.) of the classical statistical theory, which is recovered in the classical limit. The predicted distribution function is a one-parameter continuous deformation of the classical Maxwell-Boltzmann distribution and has a simple analytic form, showing power-law tails in accordance with the experimental evidence.
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
Relativistic gravitational deflection of photons
Saca, J M
2002-01-01
A relativistic analysis of the deflection of a light ray due to a massive attractive centre is here developed by solving a differential equation of the orbit of photons. Results are compared with a widely known approximate formula for the deflection obtained by Einstein in 1916. Finally, it is concluded that the results here obtained, although very close to Einstein's values, could stand out as a conclusive reference for comparison with future direct measurements of the deflection.
Relativistic approach to electromagnetic imaging
Budko, Neil
2004-01-01
A novel imaging principle based on the interaction of electromagnetic waves with a beam of relativistic electrons is proposed. Wave-particle interaction is assumed to take place in a small spatial domain, so that each electron is only briefly accelerated by the incident field. In the one-dimensional case the spatial distribution of the source density can be directly observed in the temporal spectrum of the scattered field. Whereas, in the two-dimensional case the relation between the source a...
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.
Intense Relativistic Electron Beam Investigations
1979-04-01
dif- fusion pump furnished with the electron beam machine was sized to hold vacuum rathcr thani to ,achieve rapid pump down, we were limited to 2 or...camera and lasers as well as providing an advance synchronized trigger pulse to the oscilloscopes. Since this water filled spark gap switch initiates...Equipment Source NRL 0.5 XeV 7 ohm relativistic "electron beam machine Government furnished Capacitor bank and magnetic field solenoid 4’ long with
A special relativistic heat engine
Directory of Open Access Journals (Sweden)
William S. Cariens
1983-01-01
main concepts taken from themodynamics and special relativity are those of a heat engine and E=mc2 respectively. Central to understanding the operation of this relativistic heat engine is the fact that upon heating a mass, its rest mass increases! This concept is nonexistent in classical thermodynamics. An increase in rest mass means that both the internal energy of a mass and its macroscopic kinetic energy increase!!!
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.
Energy Technology Data Exchange (ETDEWEB)
Le Bel, E.; Simonet, F. [CEA Bruyeres-le-Chatel, 91 (France); Ciurea-Borcia, R.; Matthieussent, G. [Paris-11 Univ., LPGP/CNRS, 91 - Orsay (France); Solomon, J. [Paris-11 Univ., IAS/CNRS, 91 - Orsay (France)
1999-07-01
The study of whistler waves excited by artificial electrons injection is necessary to evaluate the maximum level of trapped electrons in radiation belts: the relativistic dispersion equation for the parallel and oblique propagation cases have been solved. From the whole of the results we can draw the following conclusions: -) the frequencies of the emitted waves correspond to the range of natural whistlers, -) the growth rates and the frequencies of the excited waves are less important in the relativistic case, and -) growth rates are less important in oblique propagation than in parallel propagation (relative to the direction of the magnetic field)
Ion cyclotron and spin-flip emissions from fusion products in tokamaks
Energy Technology Data Exchange (ETDEWEB)
Arunasalam, V.; Greene, G.J.; Young, K.M.
1993-02-01
Power emission by fusion products of tokamak plasmas in their ion cyclotron range of frequencies (ICRF) and at their spin-flip resonance frequency is calculated for some specific model fusion product velocity-space distribution functions. The background plasma of say deuterium (D) is assumed to be in equilibrium with a Maxwellian distribution both for the electrons and ions. The fusion product velocity distributions analyzed here are: (1) A monoenergetic velocity space ring distribution. (2) A monoenergetic velocity space spherical shell distribution. (3) An anisotropic Maxwellian distribution with T {perpendicular} {ne} T{parallel}and with appreciable drift velocity along the confining magnetic field. Single ``dressed`` test particle spontaneous emission calculations are presented first and the radiation temperature for ion cyclotron emission (ICE) is analyzed both for black-body emission and nonequilibrium conditions. Thresholds for instability and overstability conditions are then examined and quasilinear and nonlinear theories of the electromagnetic ion cyclotron modes are discussed. Distinctions between ``kinetic or causal instabilities`` and ``hydrodynamic instabilities`` are drawn and some numerical estimates are presented for typical tokamak parameters. Semiquantitative remarks are offered on wave accessibility, mode conversion, and parametric decay instabilities as possible for spatially localized ICE. Calculations are carried out both for k{parallel} = 0 for k{parallel} {ne} 0. The effects of the temperature anisotropy and large drift velocities in the parallel direction are also examined. Finally, proton spin-flip resonance emission and absorption calculations are also presented both for thermal equilibrium conditions and for an ``inverted`` population of states.
Electron cyclotron emission imaging diagnostic system for Rijnhuizen Tokamak Project
Deng, B.H.; Hsia, R. P.; Domier, C.W.; Burns, S. R.; Hillyer, T. R.; N C Luhmann Jr.,; Oyevaar, T.; Donne, A. J. H.; R. T. P. Team,
1999-01-01
A 16-channel electron cyclotron emission (ECE) imaging diagnostic system has been developed and installed on the Rijnhuizen Tokamak Project for measuring plasma electron cyclotron emission with a temporal resolution of 2 mu s. The high spatial resolution of the system is achieved by utilizing a low
Cyclotron Lines: From Magnetic Field Strength Estimators to ...
Indian Academy of Sciences (India)
Chandreyee Maitra
2017-09-12
Sep 12, 2017 ... With forty years since the discovery of the first cyclotron line in Her X-1, there have been remarkable ... the important results related to cyclotron lines since its discovery and reviews their significance. ... context can provide, to build a complete picture for the physics of accretion and hence X-ray emission in.
Ion–Cyclotron Resonance Frequency Interval Dependence on the O ...
Indian Academy of Sciences (India)
Solar corona—ion–cyclotron waves—coronal heating—. Vlasov equation. 1. Introduction. Heating of solar corona is still an active research area. It has recently been suggested that the ion–cyclotron resonance could play a key role in the problem of coronal heating. It is generally argued that various electromagnetic plasma ...
Unstable plasma characteristics in mirror field electron cyclotron ...
Indian Academy of Sciences (India)
Electron cyclotron plasma reactor are prone to instabilities in specific input power [3–. 7] region (150–450 watts). ... Electron cyclotron resonance (ECR) plasma technology has become very important for fabrication of very large scale ... left hand polarized (LHP) wave. Shufflbotham and Thomson [4] observed several distinct.
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...
Relativistic x-ray free-electron lasers in the quantum regime.
Eliasson, Bengt; Shukla, P K
2012-06-01
We present a nonlinear theory for relativistic x-ray free-electron lasers in the quantum regime, using a collective Klein-Gordon (KG) equation (for relativistic electrons), which is coupled with the Maxwell-Poisson equations for the electromagnetic and electrostatic fields. In our model, an intense electromagnetic wave is used as a wiggler which interacts with a relativistic electron beam to produce coherent tunable radiation. The KG-Maxwell-Poisson model is used to derive a general nonlinear dispersion relation for parametric instabilities in three space dimensions, including an arbitrarily large amplitude electromagnetic wiggler field. The nonlinear dispersion relation reveals the importance of quantum recoil effects and oblique scattering of the radiation that can be tuned by varying the beam energy.
Relativistic Celestial Mechanics of the Solar System
Kopeikin, Sergei; Efroimsky, Michael; Kaplan, George
2011-09-01
objects like vectors and tensors, for example, the velocity, acceleration, force, electromagnetic field, and so on. Chapter 3 is devoted to general relativity. It explains the main ideas of the tensor calculus on curved manifolds, the theory of the affine connection and parallel transport, and the mathematical and physical foundations of Einstein's approach to gravity. Within this chapter, we have also included topics which are not well covered in standard books on general relativity: namely, the variational analysis on manifolds and the multipolar expansion of gravitational radiation. Chapter 4 introduces a detailed theory of relativistic reference frames and time scales in an N-body system comprised of massive, extended bodies - like our own solar system. Here, we go beyond general relativity and base our analysis on the scalar-tensor theory of gravity. This allows us to extend the domain of applicability of the IAU resolutions on relativistic reference frames, which in their original form were applicable only in the framework of general relativity. We explain the principles of construction of reference frames, and explore their relationship with the solutions of the gravitational field equations. We also discuss the post-Newtonian multipolemoments of the gravitational field from the viewpoint of global and local coordinates. Chapter 5 discusses the principles of derivation of transformations between reference frames in relativistic celestial mechanics. The standard parameterized post-Newtonian (PPN) formalism by K. Nordtevdt and C. Will operates with a single coordinate frame covering the entire N-body system, but it is insufficient for discussion of more subtle relativistic effects showing up in orbital and rotational motion of extended bodies. Consideration of such effects require, besides the global frame, the introduction of a set of local frames needed to properly treat each body and its internal structure and dynamics. The entire set of global and local frames
Kubo, Hitoshi; Otani, Tamaki; Otsuka, Hideki; Harada, Masafumi
2014-01-01
The purpose of this study was to evaluate the impact of a cyclotron on small-animal PET equipment installed directly above the cyclotron. The cyclotron equipment was HM-12, which has two targets, and the PET/CT equipment was Inveon. The equipment was installed in conformity to Japanese law and regulations. Before installation of the PET/CT equipment, the radiation dose, radio waves, and static and fluctuating magnetic fields were measured at the position where it would be placed, both when the cyclotron was in use and when it was not in use. After installation of the PET/CT, natural background and emission counts were measured at the same place under the same conditions. An increase of radiation dose was observed when the target nearest the PET equipment was used. There were no distinct effects of radio waves or static and fluctuating magnetic fields. A significant increase of emission counts, approximately 300 cpm, was observed when the nearest target was used. Though radio waves and static and fluctuating magnetic fields generated by running cyclotron had no influence, a significant increase in emission count was observed. Careful attention should be paid to this influence when very low-radioactivity PET measurements are done.
Infantino, Angelo; Marengo, Mario; Baschetti, Serafina; Cicoria, Gianfranco; Longo Vaschetto, Vittorio; Lucconi, Giulia; Massucci, Piera; Vichi, Sara; Zagni, Federico; Mostacci, Domiziano
2015-11-01
Biomedical cyclotrons for production of Positron Emission Tomography (PET) radionuclides and radiotherapy with hadrons or ions are widely diffused and established in hospitals as well as in industrial facilities and research sites. Guidelines for site planning and installation, as well as for radiation protection assessment, are given in a number of international documents; however, these well-established guides typically offer analytic methods of calculation of both shielding and materials activation, in approximate or idealized geometry set up. The availability of Monte Carlo codes with accurate and up-to-date libraries for transport and interactions of neutrons and charged particles at energies below 250 MeV, together with the continuously increasing power of nowadays computers, makes systematic use of simulations with realistic geometries possible, yielding equipment and site specific evaluation of the source terms, shielding requirements and all quantities relevant to radiation protection. In this work, the well-known Monte Carlo code FLUKA was used to simulate two representative models of cyclotron for PET radionuclides production, including their targetry; and one type of proton therapy cyclotron including the energy selection system. Simulations yield estimates of various quantities of radiological interest, including the effective dose distribution around the equipment, the effective number of neutron produced per incident proton and the activation of target materials, the structure of the cyclotron, the energy degrader, the vault walls and the soil. The model was validated against experimental measurements and comparison with well-established reference data. Neutron ambient dose equivalent H*(10) was measured around a GE PETtrace cyclotron: an average ratio between experimental measurement and simulations of 0.99±0.07 was found. Saturation yield of 18F, produced by the well-known 18O(p,n)18F reaction, was calculated and compared with the IAEA recommended
Effect of Ring Current Ions on Electromagnetic Ion Cyclotron Wave Dispersion Relation
Gamayunov, K. V.; Khazanov, G. V.
2006-01-01
Electromagnetic ion cyclotron (EMIC) waves are widely observed in the inner and outer magnetosphere, at geostationary orbit, at high latitudes along the plasmapause, and at the ionospheric altitudes. Interaction of the Ring Current (RC) ions and EMIC waves causes ion scattering into the loss cone and leads to decay of the RC, especially during the main phase of storms when the RC decay times of about one hour or less are observed. The oblique EMIC waves damp due to Landau resonance with the thermal plasmaspheric electrons, and subsequent transport of the dissipating wave energy into the ionosphere below causes an ionosphere temperature enhancement. Induced scattering of these waves by the plasmaspheric thermal ions leads to ion temperature enhancement, and forms a so-called hot zone near the plasmapause where the temperature of core plasma ions can reach tens of thousands of degrees. Relativistic electrons in the outer radiation belt also interact well with the EMIC waves, and during the main and/or recovery phases of the storms these electrons can easily be scattered into the loss cone over a time scale from several hours to a day. The plasma density distribution in the magnetosphere and the ion content play a critical role in EMIC wave generation and propagation, but the wave dispersion relation in the known RC-EMIC wave interaction models is assumed to be determined by the thermal plasma distribution only. In these models, the modification of the EMIC wave dispersion relation caused by the RC ions is not taken into account, and the RC ions are only treated as a source of free energy in order to generate EMIC waves. At the same time, the RC ions can dominate the thermal magnetospheric content in the night MLT sector at great L shells during the main and/or recovery storm phase. In this study, using our self-consistent RC-EMIC wave model [Khazanov et al., 2006], we simulate the May 1998 storm in order to quantify the global EMIC wave redistribution caused by
Ground pulsation magnetometer observations conjugated with relativistic electron precipitation
Yahnin, A. G.; Yahnina, T. A.; Raita, T.; Manninen, J.
2017-09-01
In this report, we investigate the role of electromagnetic ion cyclotron (EMIC) waves in production of relativistic electron precipitation (REP). Over a thousand REP events were detected from four NOAA Polar-orbiting Operational Environmental Satellites in July-December 2005. Of these, a total of 112 events were conjugated with a ground-based network of six Finnish induction coil magnetometers and one in Lovozero observatory at Kola Peninsula, Russia. The observation of geomagnetic pulsations during the conjugated events showed that about one third of them were accompanied by pulsations in the Pc1 range, which are the signature of EMIC waves. In fact, the sources of some of these EMIC waves were well outside the location of the REP event. This means that in such cases the REP events were not originated from scattering by EMIC waves. Finally, it is concluded that for this limited set of conjugated events only a quarter might be related to scattering by EMIC waves. The majority of the events are not correlated with EMIC wave signatures in ground-based observations; they were associated with either no pulsations or noise-like pulsations PiB and PiC.
Directory of Open Access Journals (Sweden)
E. E. Woodfield
2013-10-01
Full Text Available Jupiter has the most intense radiation belts of all the outer planets. It is not yet known how electrons can be accelerated to energies of 10 MeV or more. It has been suggested that cyclotron-resonant wave-particle interactions by chorus waves could accelerate electrons to a few MeV near the orbit of Io. Here we use the chorus wave intensities observed by the Galileo spacecraft to calculate the changes in electron flux as a result of pitch angle and energy diffusion. We show that, when the bandwidth of the waves and its variation with L are taken into account, pitch angle and energy diffusion due to chorus waves is a factor of 8 larger at L-shells greater than 10 than previously shown. We have used the latitudinal wave intensity profile from Galileo data to model the time evolution of the electron flux using the British Antarctic Survey Radiation Belt (BAS model. This profile confines intense chorus waves near the magnetic equator with a peak intensity at ∼5° latitude. Electron fluxes in the BAS model increase by an order of magnitude for energies around 3 MeV. Extending our results to L = 14 shows that cyclotron-resonant interactions with chorus waves are equally important for electron acceleration beyond L = 10. These results suggest that there is significant electron acceleration by cyclotron-resonant interactions at Jupiter contributing to the creation of Jupiter's radiation belts and also increasing the range of L-shells over which this mechanism should be considered.
Using Jupiter's Synchrotron Radiation as a Probe into Jupiter's Inner Radiation Belts
Bolton, S. J.; Gulkis, S.; Klein, M. J.; Thorne, R. M.
1995-01-01
The Jovian decimetric emission is caused by the combined emission of synchrotron radiation originating from the relativistic electrons trapped in Jupiter's 'Van Allen radiation belts' and thermal emission from the planet's atmosphere. Synchrotron radiation characteristics and variations (which provides insight into the physical properties of Jupiter's inner radiation belts) will be amplified and discussed.
Spectra of KeV Protons Related to Ion-Cyclotron Wave Packets
Khazanov, G. V.; Sibeck, D. G.; Tel'Nikhin, A. A.; Kronberg, T. K.
2017-01-01
We use the Fokker-Planck-Kolmogorov equation to study the statistical aspects of stochastic dynamics of the radiation belt (RB) protons driven by nonlinear electromagnetic ion-cyclotron (EMIC) wave packets. We obtain the spectra of keV protons scattered by these waves that showsteeping near the gyroresonance, the signature of resonant wave-particle interaction that cannot be described by a simple power law. The most likely mechanism for proton precipitation events in RBs is shown to be nonlinear wave-particle interaction, namely, the scattering of RB protons into the loss cone by EMIC waves.
Development of helium electron cyclotron wall conditioning on TCV
Douai, D.; Goodman, T.; Isayama, A.; Fukumoto, M.; Wauters, T.; Sozzi, C.; Coda, S.; Blanchard, P.; Figini, L.; Garavaglia, S.; Miyata, Y.; Moro, A.; Ricci, D.; Silva, M.; Theiler, C.; Vartanian, S.; Verhaegh, K.; the EUROfusion MST1 Team; the TCV Team
2018-02-01
JT-60SA envisions electron cyclotron wall conditioning (ECWC), as wall conditioning method in the presence of the toroidal field to control fuel and impurity recycling and to improve plasma performance and reproducibility. This paper reports on Helium ECWC experiments on TCV in support of JT-60SA operation. Nearly sixty Helium conditioning discharges have been successfully produced in TCV, at a toroidal field B T = 1.3 or 1.54 T, with gyrotrons at 82.7 GHz in X2 mode, mimicking ECWC operation in JT-60SA at the second harmonic of the EC wave. Discharge parameters were tuned in order to (i) minimize the time for the onset of ECWC plasmas, thus minimizing absorption of stray radiation by in-vessel components, (ii) improve discharge homogeneity by extending the discharge vertically and radially, and wall coverage, in particular of inboard surfaces where JT-60SA plasmas will be initiated, (iii) assess the efficiency of He-ECWC to deplete carbon walls from fuel. An optimized combination of vertical and radial magnetic fields, with amplitudes typically 0.1 to 0.6% of that of B T, has been determined, which resulted in lowest breakdown time, improved wall coverage and enhanced fuel removal. A standard ohmic D 2-plasma could be then sustained, whereas it would not have been possible without He-ECWC.
Applied research with cyclotron beams at FLNR JINR
Energy Technology Data Exchange (ETDEWEB)
Oganessian, Yu.Ts.; Apel, P.Yu.; Didyk, A.Yu.; Dmitriev, S.N.; Gulbekian, G.G. [Joint Inst. for Nuclear Research, Dubna, Moscow (Russian Federation). Flerov Lab. of Nuclear Reactions
1997-03-01
The Center of Applied Physics at the Flerov Laboratory carries out an R and D program comprising development of track membrane technology, materials research with heavy ion beams and production of radioisotopes. Experiments are performed on three cyclotrons: U-400, U-200 and IC-100 providing a wide variety of ion beams with the energies of 1 to 10 MeV/u. The activity on track membranes (TMs) includes studies of track formation in polymers and latent track structure, track sensitization and etching, methods of membrane testing, development of track membranes on the basis of new materials, surface modification of TMs, design and construction of facilities for track membrane production. Recent experiments on heavy ion-induced radiation damage in non-polymeric substances have been devoted to defect creation in semiconductor and dielectric single crystals. TEM, SEM, STM and `in situ` luminescent spectroscopy are used to investigate heavy ion effects. Methods for producing several isotopes of high radiochemical and isotopic purity for medical, biomedical and environmental protection applications have been developed. (author)
Forecasting the relativistic electron flux at geosynchronous orbit
Gorney, David J.; Koons, Harry C.
1992-04-01
A neural network, developed to model the temporal variations of relativistic (greater than 3 MeV) electrons at geosynchronous orbit, has been used to make reasonably accurate day-ahead forecasts of the relativistic electron flux at geosynchronous orbit. This model can be used to forecast days when internal discharges might occur on geosynchronous satellites or satellites operating within the outer Van Allen radiation belt. The neural network (in essence, a nonlinear prediction filter) consists of three layers of neurons, containing 10 neurons in the input layer, 6 neurons in a hidden layer, and 1 output neuron. The network inputs consist of ten consecutive days of the daily sum of the planetary magnetic index, Sigma Kp. The output is a prediction of the daily averaged electron flux for the tenth day. The neural network model, together with projections of Sigma Kp based on its historical behavior, can be used to make the day-ahead forecasts of the relativistic electron flux at geosynchronous orbit. A significantly better forecast is obtained by modifying the network to include one additional input, the measured daily averaged electron flux for the day prior to the forecast day, and one more neuron in the hidden layer. Both models are described in this report.
Demonstration of light reflection from the relativistic mirror
Energy Technology Data Exchange (ETDEWEB)
Pirozhkov, A S; Esirkepov, T Z; Kando, M; Fukuda, Y; Ma, J; 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 [Advanced Photon Research Center, Japan Atomic Energy Agency, 8-1 Umemidai, Kizugawa, Kyoto 619-0215 (Japan)], E-mail: pirozhkov.alexander@jaea.go.jp
2008-05-01
Electromagnetic wave frequency upshifting upon reflection from a relativistic mirror (the double Doppler effect) can be used for the generation of coherent high-frequency radiation. The reflected high-frequency pulse inherits the coherence, polarization, and temporal shape from the original laser pulse. A partly reflecting relativistic mirror (flying mirror) can be formed by a breaking wake wave created by a strong laser pulse propagating in underdense plasma [Bulanov S V et al. 2003 Phys. Rev. Lett. 91, 085001]. We present the results of the proof-of-principle experiment for frequency upshifting of the laser pulse reflected from the flying mirror. In the experiment, the breaking wake wave is created by a Ti:S laser pulse (2 TW, 76 fs) in helium plasma with the electron density of {approx}5x10{sup 19} cm{sup -3}. The incidence angle of the second laser pulse on the flying mirror is 45 deg. The reflected signal is observed in 24 shots, with the wavelength from 7 to 14 nm, which corresponds to the frequency upshifting factors from 55 to 114 and the relativistic gamma-factors from 4 to 6. The reflected signal contains at least 3x10{sup 7} photons/sr. The new source promises the generation of coherent ultrashort XUV and x-ray pulses with tunable wavelength and duration, with the possibility of focusing to record intensities.
Energy Technology Data Exchange (ETDEWEB)
Vyacheslavov, L.N.; Kandaurov, I.V.; Kruglyakov, E.P.; Losev, M.V.; Meshkov, O.I.; Sanin, A.L.
1992-02-01
Scattering radiation from a CO{sub 2} laser is used to carry out direct observations of Langmuir oscillations associated with the interaction between a high-power relativistic electron beam and a plasma. Experimental data on the frequency spectrum of the turbulence and the first results on studies of the spatial spectra of the oscillations are presented. 4 refs., 2 figs.
Relativistic Particle-In-Cell Simulation Studies of Prompt and Early Afterglows from GRBs
Nishikawa, Ken-Ichi; Hardee, Philip; Mizuno, Yosuke; Fishman, Gerald
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 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.-/
New Relativistic Particle-In-Cell Simulation Studies of Prompt and Early Afterglows from GRBs
Nishikawa, Ken-ichi; Hardee, P.; Mizuno, Y.; Zhang, B.; Medvedev, M.; Hartmann, D.; Fishman, J. F.; Preece, R.
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.
Non-relativistic Bremsstrahlung in QED: Hamiltonian vs. Path Integral Approach
Jahan, A.
2012-01-01
An alternative derivation of the radiation intensity in non-relativistic bremsstrahlung is provided utilizing the path integral formalism. By integrating out the gauge field, one obtains the effective action which it's imaginary part is interpreted as the rate of photon production during the collision.
A study on the irradiation effect of reactor materials using a cyclotron
Energy Technology Data Exchange (ETDEWEB)
Hong, Joon Hwa; Ji, Se Hwan; Kang, Yung Hwan; Park, Duk Keun; Park, Jong Man; Lee, Bong Sang; Oh, Jong Myung [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)
1994-12-01
The objectives of the present study are to develop the simulation techniques of neutron irradiation through ion irradiation using a Cyclotron and small specimen techniques and to evaluate radiation effects of reactor materials. Effects of proton or neutron irradiation on domestic 12Cr-1MoV and SA508-3 steels were evaluated by small scale specimen test techniques, i.e, small punch and miniaturized tensile test. In order to study the radiation damage mechanism, irradiation effects of the steels were investigated by means of property change tests such as microstructure, physical and thermal properties. Feasibility study on application of a magnetic non-destructive methods to evaluate radiation effects on RPV materials was performed. 109 figs, 12 tabs, 102 refs. (Author).
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 quasiparticle random phase approximation in deformed nuclei
Energy Technology Data Exchange (ETDEWEB)
Pena Arteaga, D.
2007-06-25
Covariant density functional theory is used to study the influence of electromagnetic radiation on deformed superfluid nuclei. The relativistic Hartree-Bogolyubov equations and the resulting diagonalization problem of the quasiparticle random phase approximation are solved for axially symmetric systems in a fully self-consistent way by a newly developed parallel code. Three different kinds of high precision energy functionals are investigated and special care is taken for the decoupling of the Goldstone modes. This allows the microscopic investigation of Pygmy and scissor resonances in electric and magnetic dipole fields. Excellent agreement with recent experiments is found and new types of modes are predicted for deformed systems with large neutron excess. (orig.)
Extended quasiparticle approximation for relativistic electrons in plasmas
Directory of Open Access Journals (Sweden)
V.G.Morozov
2006-01-01
Full Text Available Starting with Dyson equations for the path-ordered Green's function, it is shown that the correlation functions for relativistic electrons (positrons in a weakly coupled non-equilibrium plasmas can be decomposed into sharply peaked quasiparticle parts and off-shell parts in a rather general form. To leading order in the electromagnetic coupling constant, this decomposition yields the extended quasiparticle approximation for the correlation functions, which can be used for the first principle calculation of the radiation scattering rates in QED plasmas.
Huang, T. W.; Zhou, C. T.; Zhang, H.; Wu, S. Z.; Qiao, B.; He, X. T.; Ruan, S. C.
2017-04-01
The hosing processes of a relativistic laser pulse, electron acceleration, and betatron radiation in a parabolic plasma channel are investigated in the direct laser acceleration regime. It is shown that the laser hosing instability would result in the generation of a randomly directed off-axis electron beam and radiation source with a large divergence angle. While employing a preformed parabolic plasma channel, the restoring force provided by the plasma channel would correct the perturbed laser wave front and thus suppress the hosing instability. As a result, the accelerated electron beam and the emitted photons are well guided and concentrated along the channel axis. The employment of a proper plasma density channel can stably guide the relativistically intense laser pulse and greatly improve the properties of the electron beam and radiation source. This scheme is of great interest for the generation of high quality electron beams and radiation sources.
Symmetries of relativistic world lines
Koch, Benjamin; Muñoz, Enrique; Reyes, Ignacio A.
2017-10-01
Symmetries are essential for a consistent formulation of many quantum systems. In this paper we discuss a fundamental symmetry, which is present for any Lagrangian term that involves x˙2. As a basic model that incorporates the fundamental symmetries of quantum gravity and string theory, we consider the Lagrangian action of the relativistic point particle. A path integral quantization for this seemingly simple system has long presented notorious problems. Here we show that those problems are overcome by taking into account the additional symmetry, leading directly to the exact Klein-Gordon propagator.
Quasiparticle Dynamics in Relativistic Plasmas
Yaffe, Laurence G.
2003-06-01
Quasiparticle dynamics in relativistic plasmas associated with hot, weakly-coupled gauge theories (such as QCD at asymptotically high temperature T) can be described by an effective kinetic theory, valid on sufficiently large time and distance scales. This effective kinetic theory may be used to evaluate observables which are dominantly sensitive to the dynamics of typical ultrarelativistic excitations, to leading order in the running coupling g(T) and all orders in 1/log g(T)-1. Suitable observables include transport coefficients (viscosities and diffusion constants) and energy loss rates. This summary sketches the form of the effective theory and outlines its domain of applicability.
Relativistic atomic beam spectroscopy II
Energy Technology Data Exchange (ETDEWEB)
NONE
1989-12-31
The negative ion of H is one of the simplest 3-body atomic systems. The techniques we have developed for experimental study of atoms moving near speed of light have been productive. This proposal request continuing support for experimental studies of the H{sup -} system, principally at the 800 MeV linear accelerator (LAMPF) at Los Alamos. Four experiments are currently planned: photodetachment of H{sup -} near threshold in electric field, interaction of relativistic H{sup -} ions with matter, high excitations and double charge escape in H{sup -}, and multiphoton detachment of electrons from H{sup -}.
On the Relativistic anisotropic configurations
Shojai, F; Stepanian, A
2016-01-01
In this paper we study anisotropic spherical polytropes within the framework of general relativity. Using the anisotropic Tolman-Oppenheimer-Volkov (TOV) 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 behaviour 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.
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.
Gravitational mass of relativistic matter and antimatter
Directory of Open Access Journals (Sweden)
Tigran Kalaydzhyan
2015-12-01
Full Text Available The universality of free fall, the weak equivalence principle (WEP, is a cornerstone of the general theory of relativity, the most precise theory of gravity confirmed in all experiments up to date. The WEP states the equivalence of the inertial, m, and gravitational, mg, masses and was tested in numerous occasions with normal matter at relatively low energies. However, there is no confirmation for the matter and antimatter at high energies. For the antimatter the situation is even less clear – current direct observations of trapped antihydrogen suggest the limits −65
Magnetic field generation in relativistic shocks
Energy Technology Data Exchange (ETDEWEB)
Wiersma, J.; Achterberg, A. [Utrecht Univ., Utrecht (Germany). Sterrekundig Instituut
2005-06-01
Linear theory of the Weibel instability cannot explain magnetic field generation in relativistic shock fronts in electron-proton plasmas. The fireball model far Gamma-ray Burst afterglows requires a magnetic field in similar shock fronts between the fireball and the surrounding matter to explain the detected nonthermal afterglow radiation. We consider an analytical model of post-shock protons penetrating the hot post-shock electron plasma. The linear Weibel instability produces magnetic fields through self-enhancing current channels. Perturbations with a length-scale comparable to the electron skin depth reach the high est magnetic field before the linear theory breaks down. The electrons quench the linear proton instability so that it cannot randomize the proton velocity distribution and only converts a small fraction of the available kinetic energy of the protons into magnetic fields. We conclude that the linear Weibel instability that dominates in pair plasmas is relatively unimportant in electron-proton plasmas and that non-linear processes are probably much more important.
Energy Technology Data Exchange (ETDEWEB)
Mendez, R.; Guerrero, J. E.; Lagares, J. I.; Sansaloni, F.; Perez, J. M.; Llop, J.; Kralik, M.
2013-07-01
The most widely used for Neutron spectrometry system is formed by the Bonner spheres with an active sensor sensitive to thermal neutrons in its Center. But, the presence of strong electromagnetic fields and the hold character around a cyclotron radiation detectors active employment make unviable so it is necessary to replace it with other liabilities. In this case it has resorted to the use of Au foils such as thermal neutron detectors, found the matrix the new spectrometer response and has been validated with a source of {sup 2}52Cf for later measurements in the interior of the bunker of a cyclotron production of radioisotopes for PET. (Author)
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…
Relativistic heavy-ion physics: Experimental overview
Indian Academy of Sciences (India)
Abstract. 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.
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 correctio...
Compton Effect with Non-Relativistic Kinematics
Shivalingaswamy, T.; Kagali, B. A.
2011-01-01
In deducing the change of wavelength of x-rays scattered by atomic electrons, one normally makes use of relativistic kinematics for electrons. However, recoiling energies of the electrons are of the order of a few keV which is less than 0.2% of their rest energies. Hence the authors may ask whether relativistic formulae are really necessary. In…
Relativistic calculations of coalescing binary neutron stars
Indian Academy of Sciences (India)
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 ...
Relativistic calculations of coalescing binary neutron stars
Indian Academy of Sciences (India)
Relativistic calculations of coalescing binary neutron stars. JOSHUA FABER, PHILIPPE GRANDCLÉMENT and FREDERIC RASIO. Department of Physics and Astronomy, Northwestern University, Evanston,. IL 60208-0834, USA. E-mail: rasio@mac.com. Abstract. We have designed and tested a new relativistic Lagrangian ...
Alba, David; Crater, Horace W.; Lusanna, Luca
2012-01-01
A new formulation of relativistic classical mechanics allows a revisiting of old unsolved problems in relativistic kinetic theory and in relativistic statistical mechanics. In particular a definition of the relativistic micro-canonical partition function is given strictly in terms of the Poincar\\'e generators of an interacting N-particle system both in the inertial and non-inertial rest frames. The non-relativistic limit allows a definition of both the inertial and non-inertial micro-canonica...
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.
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.
Non-relativistic scale anomalies
Energy Technology Data Exchange (ETDEWEB)
Arav, Igal [Raymond and Beverly Sackler School of Physics and Astronomy, Tel-Aviv University,55 Haim Levanon street, Tel-Aviv, 69978 (Israel); Chapman, Shira [Perimeter Institute for Theoretical Physics,31 Caroline Street North, ON N2L 2Y5 (Canada); Oz, Yaron [Raymond and Beverly Sackler School of Physics and Astronomy, Tel-Aviv University,55 Haim Levanon street, Tel-Aviv, 69978 (Israel)
2016-06-27
We extend the cohomological analysis in arXiv:1410.5831 of anisotropic Lifshitz scale anomalies. We consider non-relativistic theories with a dynamical critical exponent z=2 with or without non-relativistic boosts and a particle number symmetry. We distinguish between cases depending on whether the time direction does or does not induce a foliation structure. We analyse both 1+1 and 2+1 spacetime dimensions. In 1+1 dimensions we find no scale anomalies with Galilean boost symmetries. The anomalies in 2+1 dimensions with Galilean boosts and a foliation structure are all B-type and are identical to the Lifshitz case in the purely spatial sector. With Galilean boosts and without a foliation structure we find also an A-type scale anomaly. There is an infinite ladder of B-type anomalies in the absence of a foliation structure with or without Galilean boosts. We discuss the relation between the existence of a foliation structure and the causality of the field theory.
Lecture Series on Relativistic Quantum Information
Fuentes, Ivette
2013-09-01
The insight that the world is fundamentally quantum mechanical inspired the development of quantum information theory. However, the world is not only quantum but also relativistic, and indeed many implementations of quantum information tasks involve truly relativistic systems. In this lecture series I consider relativistic effects on entanglement in flat and curved spacetimes. I will emphasize the qualitative differences to a non-relativistic treatment, and demonstrate that a thorough understanding of quantum information theory requires taking relativity into account. The exploitation of such relativistic effects will likely play an increasing role in the future development of quantum information theory. The relevance of these results extends beyond pure quantum information theory, and applications to foundational questions in cosmology and black hole physics will be presented.
High-Resolution Ion Cyclotron Mobility Spectrometry
Merenbloom, Samuel I.; Glaskin, Rebecca S.; Henson, Zachary B.; Clemmer, David E.
2009-01-01
A novel ion mobility spectrometry instrument incorporating a cyclotron geometry drift tube is presented. The drift tube consists of eight regions, four curved drift tubes and four ion funnels. Packets of ions are propagated around the drift tube by changing the drift field at a frequency that is resonant with the ion’s drift time through each region. The approach trims each packet of ions as it leaves and enters each new region. An electrostatic gate allows ions to be kept in the drift tube for numerous cycles, increasing the ability to resolve specified ions. We demonstrate the approach by isolating the [M+2H]2+ or [M+3H]3+ charge state of substance P as well as individual trisaccharide isomers from a mixture of melezitose and raffinose. Resolving powers in excess of 300 are obtainable with this approach. PMID:19143495
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.
Radiation processes in astrophysics
Tucker, Wallace H
1975-01-01
The purpose of this book is twofold: to provide a brief, simple introduction to the theory of radiation and its application in astrophysics and to serve as a reference manual for researchers. The first part of the book consists of a discussion of the basic formulas and concepts that underlie the classical and quantum descriptions of radiation processes. The rest of the book is concerned with applications. The spirit of the discussion is to present simple derivations that will provide some insight into the basic physics involved and then to state the exact results in a form useful for applications. The reader is referred to the original literature and to reviews for rigorous derivations.The wide range of topics covered is illustrated by the following table of contents: Basic Formulas for Classical Radiation Processes; Basic Formulas for Quantum Radiation Processes; Cyclotron and Synchrotron Radiation; Electron Scattering; Bremsstrahlung and Collision Losses; Radiative Recombination; The Photoelectric Effect; a...
Energy Technology Data Exchange (ETDEWEB)
Fraboulet, D.; Becoulet, A.; Nguyen, F
1998-11-01
To maintain the ignition state in a tokamak fusion reactor, a control must be performed on the population of alpha-products, and this implies the ability to diagnose those {alpha}-particles. It is studied here whether the detection of emission radiated in the ion cyclotron range of frequency be a reactor plasma can provide useful information concerning fusion products, especially concerning their density profile. It is shown that the detection of the radiation emitted by the fast alpha particles along their cyclotron motion can give access to moments of their distribution function. This requires to compute the phase of the emitted field, using a full-wave approach. Such a technique allows to set in a convenient way the inverse problem of the determination of the emitting {alpha}-particles distribution through the radiation detection. A brief analysis of the expected situation in a reactor-relevant plasma is given. In parallel, the 1-D full-wave code developed in this frame is also useful for studying the physics of Fast Wave plasma heating. It enables to take into account the mode conversion of the Fast Wave into the Ion Bernstein Wave that appears near each ion cyclotron resonance. Results show that higher order terms may significantly alter the energy partitioning, in hot plasma cases involving mode conversion heating and/or ion cyclotron high harmonics heating. (author) 47 refs.
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.
Neutron field inside a PET Cyclotron vault room
Energy Technology Data Exchange (ETDEWEB)
Vega C, H.R. [UAZ, C. Cipres 10, 98068 Zacatecas (Mexico); Mendez, R. [CIEMAT, Ave. Complutense 22, 28040 Madrid (Spain); Iniguez, M.P. [Universidad de Valladolid, Po Prado de la Magdalena s/n, 47011 Valladolid (Spain); Climent, J.M.; Penuelas, I. [Servicio de Medicina Nuclear de la Clinica Universitaria de Navarra, Pamplona (Spain); Barquero, R. [Hospital Universitario Rio Hortega, Valladolid (Spain)]. e-mail: fermineutron@yahoo.com
2006-07-01
The neutron field around a Positron Emission Tomography cyclotron was investigated during {sup 18} F radioisotope production with an 18 MeV proton beam. In this study the Ion Beam Application cyclotron, model Cyclone 18/9, was utilized. Measurements were carried out with a Bonner sphere neutron spectrometer with pairs of thermoluminescent dosemeters (TLD600 and TLD700) as thermal neutron detector. The TLDs readouts were utilized to unfold the neutron spectra at three different positions inside the cyclotron's vault room. With the spectra the Ambient dose equivalent was calculated. Neutron spectra unfolding were performed with the BUNKIUT code and the UTA4 response matrix. Neutron spectra were also determined by Monte Carlo calculations using a detailed model of cyclotron and vault room. (Author)
Vacuum Control Systems of the Cyclotrons in VECC, Kolkata
Roy, Anindya; Akhtar, Javed; Yadav, R. C.; Bhole, R. B.; Pal, Sarbajit; Sarkar, D.; Bhandari, R. K.
2012-11-01
VECC has undertaken the modernization of the K-130 Room Temperature Cyclotron (RTC) (operational since 1978) and commissioning of K-500 Superconducting Cyclotron (SCC) at present. The control system of RTC vacuum system has been upgraded to Programmable Logic Controller (PLC) based automated system from relay based manual system. A distributed PLC based system is under installation for SCC vacuum system. The requirement of high vacuum in both the cyclotrons (1×10-6 mbar for RTC and 5 × 10-8 mbar SCC) imposes the reliable local and remote operation of all vacuum components and instrumentation. The design and development of the vacuum control system of two cyclotrons using the Experimental Physics and Industrial Control System (EPICS) distributed real-time software tools are presented.
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)
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)
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 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
Energy Technology Data Exchange (ETDEWEB)
McMahan, M.A.
2005-09-06
In FY04, the 88-Inch Cyclotron began a new operating mode that supports a local research program in nuclear science, R&D in accelerator technology and a test facility for the National Security Space (NSS) community (the U.S. Air Force and NRO). The NSS community (and others on a cost recovery basis) can take advantage of both the light- and heavy-ion capabilities of the Cyclotron to simulate the space radiation environment. A significant portion of this work involves the testing of microcircuits for single event effects. The experimental areas within the building that are used for the radiation effects testing are now called the Berkeley Accelerator and Space Effects (BASE) facility. Improvements to the facility to provide increased reliability, quality assurance and new capabilities are underway and will be discussed. These include a 16 AMeV ''cocktail'' of beams for heavy ion testing, a neutron beam, more robust dosimetry, and other upgrades.
A new way to measure the electron cyclotron frequency
Palmer, F. L.
1993-03-01
A method is described for using spin flips to measure the 0 to 1 cyclotron transition frequency of a single electron in a Penning trap. Detection can be accomplished with magnetic bottles of 10 T/m2 or less, thereby greatly reducing the thermal broadening of the cyclotron line. This method complements a recently published technique for measuring the anomaly frequency, making a more precise measurement of the electron anomaly ratio possible.
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....
PET computer programs for use with the 88-inch cyclotron
Energy Technology Data Exchange (ETDEWEB)
Gough, R.A.; Chlosta, L.
1981-06-01
This report describes in detail several offline programs written for the PET computer which provide an efficient data management system to assist with the operation of the 88-Inch Cyclotron. This function includes the capability to predict settings for all cyclotron and beam line parameters for all beams within the present operating domain of the facility. The establishment of a data base for operational records is also described from which various aspects of the operating history can be projected.
Relativistic inverse Compton scattering of photons from the early universe.
Malu, Siddharth; Datta, Abhirup; Colafrancesco, Sergio; Marchegiani, Paolo; Subrahmanyan, Ravi; Narasimha, D; Wieringa, Mark H
2017-12-05
Electrons at relativistic speeds, diffusing in magnetic fields, cause copious emission at radio frequencies in both clusters of galaxies and radio galaxies through non-thermal radiation emission called synchrotron. However, the total power radiated through this mechanism is ill constrained, as the lower limit of the electron energy distribution, or low-energy cutoffs, for radio emission in galaxy clusters and radio galaxies, have not yet been determined. This lower limit, parametrized by the lower limit of the electron momentum - pmin - is critical for estimating the total energetics of non-thermal electrons produced by cluster mergers or injected by radio galaxy jets, which impacts the formation of large-scale structure in the universe, as well as the evolution of local structures inside galaxy clusters. The total pressure due to the relativistic, non-thermal population of electrons can be measured using the Sunyaev-Zel'dovich Effect, and is critically dependent on pmin, making the measurement of this non-thermal pressure a promising technique to estimate the electron low-energy cutoff. We present here the first unambiguous detection of this Sunyaev-Zel'dovich Effect for a non-thermal population of electrons in a radio galaxy jet/lobe, located at a significant distance away from the center of the Bullet cluster of galaxies.
Relativistic analysis of stochastic kinematics
Giona, Massimiliano
2017-10-01
The relativistic analysis of stochastic kinematics is developed in order to determine the transformation of the effective diffusivity tensor in inertial frames. Poisson-Kac stochastic processes are initially considered. For one-dimensional spatial models, the effective diffusion coefficient measured in a frame Σ moving with velocity w with respect to the rest frame of the stochastic process is inversely proportional to the third power of the Lorentz factor γ (w ) =(1-w2/c2) -1 /2 . Subsequently, higher-dimensional processes are analyzed and it is shown that the diffusivity tensor in a moving frame becomes nonisotropic: The diffusivities parallel and orthogonal to the velocity of the moving frame scale differently with respect to γ (w ) . The analysis of discrete space-time diffusion processes permits one to obtain a general transformation theory of the tensor diffusivity, confirmed by several different simulation experiments. Several implications of the theory are also addressed and discussed.
Magnetohydrodynamic production of relativistic jets.
Meier, D L; Koide, S; Uchida, Y
2001-01-05
A number of astronomical systems have been discovered that generate collimated flows of plasma with velocities close to the speed of light. In all cases, the central object is probably a neutron star or black hole and is either accreting material from other stars or is in the initial violent stages of formation. Supercomputer simulations of the production of relativistic jets have been based on a magnetohydrodynamic model, in which differential rotation in the system creates a magnetic coil that simultaneously expels and pinches some of the infalling material. The model may explain the basic features of observed jets, including their speed and amount of collimation, and some of the details in the behavior and statistics of different jet-producing sources.
Energy Technology Data Exchange (ETDEWEB)
King, M.; Gray, R.J.; Powell, H.W.; MacLellan, D.A.; Gonzalez-Izquierdo, B. [SUPA Department of Physics, University of Strathclyde, Glasgow G4 0NG (United Kingdom); Stockhausen, L.C. [Centro de Laseres Pulsados (CLPU), Parque Cientifico, Calle del Adaja, s/n. 37185 Villamayor, Salamanca (Spain); Hicks, G.S.; Dover, N.P. [The John Adams Institute for Accelerator Science, Blackett Laboratory, Imperial College London, London SW7 2BZ (United Kingdom); Rusby, D.R. [SUPA Department of Physics, University of Strathclyde, Glasgow G4 0NG (United Kingdom); Central Laser Facility, STFC Rutherford Appleton Laboratory, Oxfordshire OX11 0QX (United Kingdom); Carroll, D.C. [Central Laser Facility, STFC Rutherford Appleton Laboratory, Oxfordshire OX11 0QX (United Kingdom); Padda, H. [SUPA Department of Physics, University of Strathclyde, Glasgow G4 0NG (United Kingdom); Torres, R. [Centro de Laseres Pulsados (CLPU), Parque Cientifico, Calle del Adaja, s/n. 37185 Villamayor, Salamanca (Spain); Kar, S. [Centre for Plasma Physics, Queens University Belfast, Belfast BT7 1NN (United Kingdom); Clarke, R.J.; Musgrave, I.O. [Central Laser Facility, STFC Rutherford Appleton Laboratory, Oxfordshire OX11 0QX (United Kingdom); Najmudin, Z. [The John Adams Institute for Accelerator Science, Blackett Laboratory, Imperial College London, London SW7 2BZ (United Kingdom); Borghesi, M. [Centre for Plasma Physics, Queens University Belfast, Belfast BT7 1NN (United Kingdom); Neely, D. [Central Laser Facility, STFC Rutherford Appleton Laboratory, Oxfordshire OX11 0QX (United Kingdom); McKenna, P., E-mail: paul.mckenna@strath.ac.uk [SUPA Department of Physics, University of Strathclyde, Glasgow G4 0NG (United Kingdom)
2016-09-01
At sufficiently high laser intensities, the rapid heating to relativistic velocities and resulting decompression of plasma electrons in an ultra-thin target foil can result in the target becoming relativistically transparent to the laser light during the interaction. Ion acceleration in this regime is strongly affected by the transition from an opaque to a relativistically transparent plasma. By spatially resolving the laser-accelerated proton beam at near-normal laser incidence and at an incidence angle of 30°, we identify characteristic features both experimentally and in particle-in-cell simulations which are consistent with the onset of three distinct ion acceleration mechanisms: sheath acceleration; radiation pressure acceleration; and transparency-enhanced acceleration. The latter mechanism occurs late in the interaction and is mediated by the formation of a plasma jet extending into the expanding ion population. The effect of laser incident angle on the plasma jet is explored.
Wave-driven butterfly distribution of Van Allen belt relativistic electrons.
Xiao, Fuliang; Yang, Chang; Su, Zhenpeng; Zhou, Qinghua; He, Zhaoguo; He, Yihua; Baker, D N; Spence, H E; Funsten, H O; Blake, J B
2015-10-05
Van Allen radiation belts consist of relativistic electrons trapped by Earth's magnetic field. Trapped electrons often drift azimuthally around Earth and display a butterfly pitch angle distribution of a minimum at 90° further out than geostationary orbit. This is usually attributed to drift shell splitting resulting from day-night asymmetry in Earth's magnetic field. However, direct observation of a butterfly distribution well inside of geostationary orbit and the origin of this phenomenon have not been provided so far. Here we report high-resolution observation that a unusual butterfly pitch angle distribution of relativistic electrons occurred within 5 Earth radii during the 28 June 2013 geomagnetic storm. Simulation results show that combined acceleration by chorus and magnetosonic waves can successfully explain the electron flux evolution both in the energy and butterfly pitch angle distribution. The current provides a great support for the mechanism of wave-driven butterfly distribution of relativistic electrons.
Ion source and injection line for high intensity medical cyclotron.
Jia, XianLu; Guan, Fengping; Yao, Hongjuan; Zhang, TianJue; Yang, Jianjun; Song, Guofang; Ge, Tao; Qin, Jiuchang
2014-02-01
A 14 MeV high intensity compact cyclotron, CYCIAE-14, was built at China Institute of Atomic Energy (CIAE). An injection system based on the external H- ion source was used on CYCIAE-14 so as to provide high intensity beam, while most positron emission tomography cyclotrons adopt internal ion source. A beam intensity of 100 μA/14 MeV was extracted from the cyclotron with a small multi-cusp H- ion source (CIAE-CH-I type) and a short injection line, which the H- ion source of 3 mA/25 keV H- beam with emittance of 0.3π mm mrad and the injection line of with only 1.2 m from the extraction of ion source to the medial plane of the cyclotron. To increase the extracted beam intensity of the cyclotron, a new ion source (CIAE-CH-II type) of 9.1 mA was used, with maximum of 500 μA was achieved from the cyclotron. The design and test results of the ion source and injection line optimized for high intensity acceleration will be given in this paper.
Testing relativistic gravity with binary and millisecond pulsars
Taylor, J H
1993-01-01
Binary and millisecond pulsars oiler unique opportunities for high precision experiments in relativistic gravity, probing well beyond the weak—ﬁeld, slowimotion limit of all previous experimental tests. 'I‘hey also provide the means for accurate measurements of neutron star masses, plao ing rigorous constraints on the energy density 01' low-frequency gravitational radiation in the universe, and a number of other significant results. The first known binary pulsar, BSR BI913+l6, has now been observed [or more than 18 years. Its timing measurements have conclusively established the ex~ istence, quadrupolar nature, and propagation speed of gravitational waves; the results are presently in accord with general relativity at, the 0.4% level. A more recently discovered binary pulsar, PSR B1534+12, has provided clean access to a test of gravity under stronghold conditions, independent of grav— itational radiation effects. In this paper I summarize and update the status of experiments involving these two pulsar...
Some lessons from relativistic reduction models
Ghirardi, Gian Carlo
1999-01-01
We reconsider some recently proposed relativistic dynamical reduction models and we point out the new conceptual picture about reduction processes that they impose on our considerations. Ignoring the specific technical difficulties of such generalizations we show that the just mentioned picture fits perfectly the natural ontology of the dynamical reduction program and yields a consistent description of macro-objectification in a relativistic and nonlocal context. We consider recent criticisms of the relativistic dynamical reduction program and we show that they are inappropriate, the reason being that they derive from serious misunderstandings of some technical and conceptual points of the theory. (53 refs).
The relativistic Black-Scholes model
Trzetrzelewski, Maciej
2017-02-01
The Black-Scholes equation, after a certain coordinate transformation, is equivalent to the heat equation. On the other hand the relativistic extension of the latter, the telegraphers equation, can be derived from the Euclidean version of the Dirac equation. Therefore, the relativistic extension of the Black-Scholes model follows from relativistic quantum mechanics quite naturally. We investigate this particular model for the case of European vanilla options. Due to the notion of locality incorporated in this way, one finds that the volatility frown-like effect appears when comparing to the original Black-Scholes model.
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.
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.
Time evolution of bremsstrahlung and ion production of an electron cyclotron resonance ion source
Energy Technology Data Exchange (ETDEWEB)
Tarvainen, Ollie [Los Alamos National Laboratory; Ropponen, Tommi [UNIV OF JYVASKYLA; Jones, Peter [UNIV OF JYVASKYLA; Peura, Pauli [UNIV OF JYVASKYLA
2008-01-01
Bremsstrahlung radiation measurement is one of the most commonly used plasma diagnostics methods. Most of the bremsstrahlung measurements with electron cyclotron resonance (ECR) ion sources have been performed in continuous operation mode yielding information only on the steady state bremsstrahlung emission. This article describes the results of bremsstrahlung and ion current measurement with the JYFL 14 GHz ECRIS operated in pulsed mode. The experiments reveal information about the bremsstrahlung radiation in plasma conditions before reaching the equilibrium. The time scale of bremsstrahlung production is compared to ion production time scale for different charge states. The bremsstrahlung data is presented with 2 millisecond time intervals as a function of neutral gas pressure and microwave power. Data from hundreds of microwave pulses is combined in order to have a sufficient amount of events at each time step. The relevant plasma physics phenomena during both, the leading and the trailing edge of the RF pulse, are discussed.
Energy Technology Data Exchange (ETDEWEB)
Videira, Heber S., E-mail: heber@cyclopet.com [CYCLOPET Radiofarmacos LTDA., Curitiba, PR (Brazil); Passaro, Bruno M.; Gonzalez, Julia A.; Guimaraes, Maria Ines C.C.; Buchpigue, Carlos A. [Centro de Medicina Nuclear (CMN) do InRad HCFMUSP, Sao Paulo, SP (Brazil)
2012-08-15
According to the National Nuclear Energy Commission (CNEN) resolution 112/2011, administrative controls must be applied during the construction of a cyclotron and documents must be created showing that the facility can operate without radiological risks, referring even to the shielding efficiency. This study aimed to perform the analysis of the construction and efficiency of the bunker built for shielding, in the cyclotron of University of Sao Paulo Medical School Health System. This was possible through the measurements of a radiometric survey in normal working conditions, and testing related to compression resistance and density. The results showed that the compression resistance of the concrete used is higher than the expected value and the average density value obtained is within the tolerated limits. The radiometric survey results showed that the levels of ionizing radiation are well below the established limits. (author)
Electromagnetic cyclotron waves near the proton cyclotron frequency in the solar wind
Jian, Lan K.; Boardsen, Scott; Moya, Pablo; Stevens, Michael; Alexander, Robert; Vinas, Adolfo
2015-04-01
Strong narrow-band electromagnetic waves around the proton cyclotron frequency (fpc) have been found sporadically in the solar wind from 0.3 to 0.7 AU during MESSENGER spacecraft’s cruise phase. These waves are transverse and circularly polarized, and they propagate in directions quasi-parallel to the magnetic field. The wave power decreases quadratically with heliocentric distance, faster than the trend if assuming the conservation of Poynting flux for wave packets, suggesting there is energy dissipation from the waves, which could contribute to the heating and acceleration of solar wind plasma. Although the wave frequency is a few times of fpc in the spacecraft frame, it is a fraction of fpc in the solar wind plasma frame after removing the Doppler shift effect. In this frequency range, the waves can be left-hand (LH) polarized ion cyclotron waves or right-hand (RH) polarized magnetosonic waves. Because the waves are LH or RH polarized in the spacecraft frame with otherwise nearly identical characteristics, they could be due to Doppler shift of a same type of waves or a mixture of waves with intrinsically different polarizations. Through the assistance of audification, we have studied the long-lasting wave events in 2005 using high-cadence magnetic field data from the Wind mission. Statistically, in contrast with general solar wind, the protons at these waves are distributed closer to the proton instability thresholds, while the alpha particles at these waves are distributed further away from the alpha instability thresholds. For selected events of extensive waves, the ion distribution is analyzed in detail. A mixture of temperature anisotropies for core protons, beam protons, and alpha particles, as well as proton beam drift are often found in such events. We conduct linear wave dispersion analysis using these ion moments to examine whether these waves can be explained by the local generation of kinetic instabilities such as the LH ion cyclotron, the RH
Yi, Longqing; Shen, Baifei; Pukhov, Alexander; Fülöp, Tünde
2017-10-01
Magnetic reconnection (MR) in the relativistic regime is generally thought to be responsible for powering rapid bursts of non-thermal radiation in astrophysical events. It is therefore of significant importance to study how the field energy is transferred to the plasma to power the observed emission. However, due to the difficulty in making direct measurements in astrophysical systems or achieving relativistic MR in laboratory environments, the particle acceleration is usually studied using fully kinetic PIC simulations. Here we present a numerical study of a readily available (TW-mJ-class) laser interacting with a micro-scale plasma slab. The simulations show when the electron beams excited on both sides of the slab approach the end of the plasma structure, ultrafast relativistic MR occurs. As the field topology changes, the explosive release of magnetic energy results in emission of relativistic electron jets with cut-off energy 12 MeV. The proposed novel scenario can be straightforwardly implemented in experiments, and might significantly improve the understanding of fundamental questions such as field dissipation and particle acceleration in relativistic MR. This work is supported by the Knut and Alice Wallenberg Foundation and the European Research Council (ERC-2014-CoG Grant 64712).
High-frequency electromagnetic radiation of germanium crystals in magnetic fields
Directory of Open Access Journals (Sweden)
G.V. Milenin
2017-07-01
Full Text Available The cyclotron radiation of plasma of thermal carriers of germanium crystals, which is not in the state of thermodynamic equilibrium with semiconductor, has been experimentally confirmed.
Energy Technology Data Exchange (ETDEWEB)
Fraboulet, D.
1996-09-17
Detection of {alpha}(3.5 MeV) fusion products will be of major importance for the achievement of self sustained discharges in fusion thermonuclear reactors. Due to their cyclotronic gyration in the confining magnetic field of a tokamak, {alpha} particles are suspected to radiate in the radio-frequency band [RF: 10-500 MHz]. Our aim is to determine whether detection of RF emission radiated from a reactor plasma can provide information concerning those fusion products. We observed experimentally that the RF emission radiated from fast ions situated in the core of the discharge is detectable with a probe located at the plasma edge. For that purpose, fast temporal acquisition of spectral power was achieved in a narrow frequency band. We also propose two complementary models for this emission. In the first one, we describe locally the energy transfer between the photon population and the plasma and we compute the radiation equilibrium taking place in the tokamak. {alpha} particles are not the unique species involved in the equilibrium and it is necessary to take into account all other species present in the plasma (Deuterium, Tritium, electrons,...). Our second model consists in the numerical resolution of the Maxwell-Vlasov with the use of a variational formulation, in which all polarizations are considered and the 4 first cyclotronic harmonics are included in a 1-D slab geometry. The development of this second model leads to the proposal for an experimental set up aiming to the feasibility demonstration of a routine diagnostic providing the central {alpha} density in a reactor. (author). 166 refs.
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.
Coherent states for the relativistic harmonic oscillator
Aldaya, Victor; Guerrero, J.
1995-01-01
Recently we have obtained, on the basis of a group approach to quantization, a Bargmann-Fock-like realization of the Relativistic Harmonic Oscillator as well as a generalized Bargmann transform relating fock wave functions and a set of relativistic Hermite polynomials. Nevertheless, the relativistic creation and annihilation operators satisfy typical relativistic commutation relations of the Lie product (vector-z, vector-z(sup dagger)) approximately equals Energy (an SL(2,R) algebra). Here we find higher-order polarization operators on the SL(2,R) group, providing canonical creation and annihilation operators satisfying the Lie product (vector-a, vector-a(sup dagger)) = identity vector 1, the eigenstates of which are 'true' coherent states.
Electron cyclotron emission radiometer upgrade on the J-TEXT tokamak
Energy Technology Data Exchange (ETDEWEB)
Yang, Z. J.; Pan, X. M., E-mail: panxiaoming@hust.edu.cn; Ma, X. D.; Ruan, B. W.; Zhou, R. B.; Zhang, C. [State Key Laboratory of Advanced Electromagnetic Engineering and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074 (China)
2016-11-15
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 B{sub T} = 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 B{sub T} = 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 B{sub T}, 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.
Nuclear curvature energy in relativistic models
Energy Technology Data Exchange (ETDEWEB)
Centelles, M.; Vinas, X. [Departament dEstructura i Constituents de la Materia, Facultat de Fisica, Universitat de Barcelona, Diagonal 647, E-08028 Barcelona (Spain); Schuck, P. [Institut National de Physique Nucleaire et de Physique des Particules, Centre National de la Recherche Scientifique (CNRS--IN2P3), Universite Joseph Fourier, Institut des Sciences Nucleaires, 53 Avenue des Martyrs, F-38026 Grenoble Cedex (France)
1996-02-01
The difficulties arising in the calculation of the nuclear curvature energy are analyzed in detail, especially with reference to relativistic models. It is underlined that the implicit dependence on curvature of the quantal wave functions is directly accessible only in a semiclassical framework. It is shown that also in the relativistic models quantal and semiclassical calculations of the curvature energy are in good agreement. {copyright} {ital 1996 The American Physical Society.}
Relativistic DNLS and Kaup-Newell Hierarchy
Pashaev, Oktay K.; Lee, Jyh-Hao
2017-07-01
By the recursion operator of the Kaup-Newell hierarchy we construct the relativistic derivative NLS (RDNLS) equation and the corresponding Lax pair. In the nonrelativistic limit c → ∞ it reduces to DNLS equation and preserves integrability at any order of relativistic corrections. The compact explicit representation of the linear problem for this equation becomes possible due to notions of the q-calculus with two bases, one of which is the recursion operator, and another one is the spectral parameter.
Q-oscillators and relativistic position operators
Energy Technology Data Exchange (ETDEWEB)
Arik, M. (Dept. of Mathematics, Istanbul Technical Univ. (Turkey)); Mungan, M. (Dept. of Physics, Bogazici Univ., Istanbul (Turkey))
1992-05-21
We investigate the multi-dimensional q-oscillator whose commutation relations are invariant under the quantum group. The no-interaction limit corresponds to a contraction of the q-oscillator algebra and yields relativistic position operators which can be expressed in terms of the generators of the Poincare group. This leads to the interpretation of the interacting q-oscillator as an relativistic quantum system and results in a hamiltonian whose spectrum is exactly exponential. (orig.).
Recent achievements in Tc-99m radiopharmaceutical direct production by medical cyclotrons.
Boschi, Alessandra; Martini, Petra; Pasquali, Micol; Uccelli, Licia
2017-09-01
99mTc is the most commonly used radionuclide in the field of diagnostic imaging, a noninvasive method intended to diagnose a disease, assess the disease state and monitor the effects of treatments. Annually, the use of 99mTc, covers about 85% of nuclear medicine applications. This isotope releases gamma rays at about the same wavelength as conventional X-ray diagnostic equipment, and owing to its short half-life (t½ = 6 h) is ideal for diagnostic nuclear imaging. A patient can be injected with a small amount of 99mTc and within 24 h almost 94% of the injected radionuclide would have decayed and left the body, limiting the patient's radiation exposure. 99mTc is usually supplied to hospitals through a 99Mo/99mTc radionuclide generator system where it is produced from the β decay of the parent nuclide 99Mo (t½ = 66 h), which is produced in nuclear reactors via neutron fission. Recently, the interruption of the global supply chain of reactor-produced 99Mo, has forced the scientific community to investigate alternative production routes for 99mTc. One solution was to consider cyclotron-based methods as potential replacement of reactor-based technology and the nuclear reaction 100Mo(p,2n)99mTc emerged as the most worthwhile approach. This review reports some achievements about 99mTc produced by medical cyclotrons. In particular, the available technologies for target design, the most efficient extraction and separation procedure developed for the purification of 99mTc from the irradiated targets, the preparation of high purity 99mTc radiopharmaceuticals and the first clinical studies carried out with cyclotron produced 99mTc are described.
Ion cyclotron and spin-flip emissions from fusion products in tokamaks
Energy Technology Data Exchange (ETDEWEB)
Arunasalam, V.; Greene, G.J.; Young, K.M.
1993-02-01
Power emission by fusion products of tokamak plasmas in their ion cyclotron range of frequencies (ICRF) and at their spin-flip resonance frequency is calculated for some specific model fusion product velocity-space distribution functions. The background plasma of say deuterium (D) is assumed to be in equilibrium with a Maxwellian distribution both for the electrons and ions. The fusion product velocity distributions analyzed here are: (1) A monoenergetic velocity space ring distribution. (2) A monoenergetic velocity space spherical shell distribution. (3) An anisotropic Maxwellian distribution with T [perpendicular] [ne] T[parallel]and with appreciable drift velocity along the confining magnetic field. Single dressed'' test particle spontaneous emission calculations are presented first and the radiation temperature for ion cyclotron emission (ICE) is analyzed both for black-body emission and nonequilibrium conditions. Thresholds for instability and overstability conditions are then examined and quasilinear and nonlinear theories of the electromagnetic ion cyclotron modes are discussed. Distinctions between kinetic or causal instabilities'' and hydrodynamic instabilities'' are drawn and some numerical estimates are presented for typical tokamak parameters. Semiquantitative remarks are offered on wave accessibility, mode conversion, and parametric decay instabilities as possible for spatially localized ICE. Calculations are carried out both for k[parallel] = 0 for k[parallel] [ne] 0. The effects of the temperature anisotropy and large drift velocities in the parallel direction are also examined. Finally, proton spin-flip resonance emission and absorption calculations are also presented both for thermal equilibrium conditions and for an inverted'' population of states.
SIMULATIONS AND THEORY OF ION INJECTION AT NON-RELATIVISTIC COLLISIONLESS SHOCKS
Energy Technology Data Exchange (ETDEWEB)
Caprioli, Damiano; Pop, Ana-Roxana; Spitkovsky, Anatoly, E-mail: caprioli@astro.princeton.edu [Department of Astrophysical Sciences, Princeton University, 4 Ivy Ln., Princeton, NJ 08544 (United States)
2015-01-10
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.
Relativistic entropy and related Boltzmann kinetics
Energy Technology Data Exchange (ETDEWEB)
Kaniadakis, G. [Politecnico di Torino (Italy). Dipartimento di Fisica
2009-06-15
It is well known that the particular form of the two-particle correlation function, in the collisional integral of the classical Boltzmann equation, fixes univocally the entropy of the system, which turns out to be the Boltzmann-Gibbs-Shannon entropy. In the ordinary relativistic Boltzmann equation, some standard generalizations, with respect to its classical version, imposed by the special relativity, are customarily performed. The only ingredient of the equation, which tacitly remains in its original classical form, is the two-particle correlation function, and this fact imposes that also the relativistic kinetics is governed by the Boltzmann-Gibbs-Shannon entropy. Indeed the ordinary relativistic Boltzmann equation admits as stationary stable distribution, the exponential Juttner distribution. Here, we show that the special relativity laws and the maximum entropy principle suggest a relativistic generalization also of the two-particle correlation function and then of the entropy. The so obtained, fully relativistic Boltzmann equation, obeys the H-theorem and predicts a stationary stable distribution, presenting power law tails in the high-energy region. The ensued relativistic kinetic theory preserves the main features of the classical kinetics, which recovers in the c{yields}{infinity} limit. (orig.)
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.
High Efficiency Energy Extraction from a Relativistic Electron Beam in a Strongly Tapered Undulator
Sudar, N.; Musumeci, P.; Duris, J.; Gadjev, I.; Polyanskiy, M.; Pogorelsky, I.; Fedurin, M.; Swinson, C.; Kusche, K.; Babzien, M.; Gover, A.
2016-10-01
We present results of an experiment where, using a 200 GW CO2 laser seed, a 65 MeV electron beam was decelerated down to 35 MeV in a 54-cm-long strongly tapered helical magnetic undulator, extracting over 30% of the initial electron beam energy to coherent radiation. These results, supported by simulations of the radiation field evolution, demonstrate unparalleled electro-optical conversion efficiencies for a relativistic beam in an undulator field and represent an important step in the development of high peak and average power coherent radiation sources.
Slapak, Rikard; Gunell, Herbert; Hamrin, Maria
2017-04-01
We have investigated a case of inverse ion-cyclotron damping taking place in the northern terrestrial magnetospheric cusp, exciting waves at the ion-cyclotron frequency and its harmonics. Magnetosheath influx in the cusps and the effect of convection and magnetic mirroring give rise to parallel velocity shears, dvallel/dx\\perp, often associated with instabilities in the plasma and corresponding ion-cyclotron waves, whose evolution is described by a damping factor. This damping factor depends on, for example, the wave numbers and the velocity shear itself and can under certain conditions be negative, hence describing inverse damping (or wave growth). However, an additional required condition for inverse ion-cyclotron damping is a velocity shear in the magnetic field-aligned ion-bulk flow, and this condition is only met for magnetosheath influx in the northern cusp, as oppose to the southern cusp. The ion-cyclotron waves are primarily seen as peaks in the magnetic-field spectral densities, as presented by Slapak et al., [GRL (2016), doi:10.1002/2016GL071680]. The corresponding peaks in the electric-field spectral densities are not as profound, suggesting a background electric field noise or other processes of wave generation causing the electric spectral densities to smoothen out more compared to the magnetic counterpart. We note that some ion-cyclotron wave activity is present in a few similar shear events in the southern cusp, which indicates that other mechanisms generating ion-cyclotron waves may also be present during such conditions.
Observation of relativistic antihydrogen atoms
Energy Technology Data Exchange (ETDEWEB)
Blanford, Glenn DelFosse
1998-01-01
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 < p < 9 GeV/c) antiprotons and a jet of molecular hydrogen gas. Since the neutral antihydrogen does not bend in the antiproton source magnets, the detectors could be located far from the interaction point on a beamline tangent to the storage ring. The detection of the antihydrogen is accomplished by ionizing the atoms far from the interaction point. The positron is deflected by a magnetic spectrometer and detected, as are the back to back photons resulting from its annihilation. The antiproton travels a distance long enough for its momentum and time of flight to be measured accurately. A statistically significant sample of 101 antihydrogen atoms has been observed. A measurement of the cross section for {bar H}{sup 0} production is outlined within. The cross section corresponds to the process where a high momentum antiproton causes e{sup +} e{sup -} pair creation near a nucleus with the e{sup +} 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.
Design of RF system for CYCIAE-230 superconducting cyclotron
Energy Technology Data Exchange (ETDEWEB)
Yin, Zhiguo, E-mail: bitbearAT@hotmail.com; Ji, Bin; Fu, Xiaoliang; Cao, Xuelong; Zhao, Zhenlu; Zhang, Tinajue
2017-05-11
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.
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.
Energy Technology Data Exchange (ETDEWEB)
Lusanna, Luca, E-mail: lusanna@fi.infn.it [Sezione INFN di Firenze, Polo Scientifico, Via Sansone 1, 50019 Sesto Fiorentino (Italy)
2011-07-08
After a review of the problems induced by the Lorentz signature of Minkowski space-time, like the need of a clock synchronization convention for the definition of 3-space and the complexity of the notion of relativistic center of mass, there is the introduction of a new formulation of relativistic quantum mechanics compatible with the theory of relativistic bound states. In it the zeroth postulate of non-relativistic quantum mechanics is not valid and the physics is described in the rest frame by a Hilbert space containing only relative variables. The non-locality of the Poincare' generators imply a kinematical non-locality and non-separability influencing the theory of relativistic entanglement and not connected with the standard quantum non-locality.
Energy Technology Data Exchange (ETDEWEB)
Larson, S.M.; Finn, R.D.
1995-07-17
This research continues the long term goals 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. This program fits into the nuclear medicine component of DOE`s mission, which is aimed at enhancing the beneficial applications of radiation, radionuclides, and stable isotopes in the diagnosis, study and treatment of human diseases. The grant includes 3 interactive components: Radiochemistry/Cyclotron; Pharmacology/Immunology; and Imaging Physics. An essential strategy is as follows: novel radionuclides and radiotracers developed in the Radiochemistry/Section under the DOE grant during the 1992--1995 will be employed in the Pharmacology/Immunology component in the period 1996--1999. Imaging Physics resolves relevant imaging related physics issues that arise during the experimentation that results. In addition to the basic research mission, this project also provides a basis for training of research scientists in radiochemistry, immunology, bioengineering and imaging physics.
Ion cyclotron range of frequencies heating of plasma with small impurity production
Ohkawa, Tihiro
1987-01-01
Plasma including plasma ions is magnetically confined by a magnetic field. The plasma has a defined outer surface and is intersected by resonance surfaces of respective common ion cyclotron frequency of a predetermined species of plasma ions moving in the magnetic field. A radio frequency source provides radio frequency power at a radio frequency corresponding to the ion cyclotron frequency of the predetermined species of plasma ions moving in the field at a respective said resonance surface. RF launchers coupled to the radio frequency source radiate radio frequency energy at the resonance frequency onto the respective resonance surface within the plasma from a plurality of locations located outside the plasma at such respective distances from the intersections of the respective resonance surface and the defined outer surface and at such relative phases that the resulting interference pattern provides substantially null net radio frequency energy over regions near and including substantial portions of the intersections relative to the radio frequency energy provided thereby at other portions of the respective resonance surface within the plasma.
Low magnetic field cooling of lepton plasmas via cyclotron-cavity resonance
Hunter, E. D.; Evetts, N.; Fajans, J.; Hardy, W. N.; Landsberger, H.; Mcpeters, R.; Wurtele, J. S.
2018-01-01
Pure electron or pure positron plasmas held in magnetic fields B radiate energy because of the cyclotron motion of the plasma particles; nominally, the plasmas should cool to the often cryogenic temperatures of the trap in which they are confined. However, the cyclotron cooling rate for leptons is (1/4 s)(B/1 T)2, and significant cooling is not normally observed unless B ≳ 1 T . Cooling to the trap temperatures of ˜10 K is particularly difficult to attain. Here, we show that dramatically higher cooling rates (×100) and lower temperatures (÷1000) can be obtained if the plasmas are held in electromagnetic cavities rather than in effectively free space conditions. We find that plasmas with up to 107 particles can be cooled in fields close to 0.15 T, much lower than 1 T commonly thought to be necessary to obtain plasma cooling. Appropriate cavities can be constructed with only minor modifications to the standard Penning-Malmberg trap structures.
Shielding for a cyclotron used for medical isotope production in China.
Pevey, R; Miller, L F; Marshall, B J; Townsend, L W; Alvord, B
2005-01-01
Monte Carlo and discrete ordinate calculations have been performed to determine the doses at several locations in a positron emission tomography (PET) facility in China, where the radiation source is a cyclotron that is used for the production of the isotopes necessary for PET scans. The energy-dependent neutron source term is obtained by calculations using the ALICE code, and is interpolated for input to Monte Carlo and discrete ordinate calculations. The building that houses the cyclotron has a labyrinth of walls to minimise dose to operators and to other occupants of the building. Unbiased Monte Carlo calculations did not converge after more than one week of CPU time, whereas direction biasing alone resulted in convergence in several days. A study of several biasing techniques indicated that about a factor of 3 in computational efficiency is obtained using evaluated biasing methods. The use of adjoint fluxes for biasing Monte Carlo calculations can improve computational efficiencies by one or two orders of magnitude for some problems.
2010-08-12
... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF COMMERCE International Trade Administration National Superconducting Cyclotron Laboratory of Michigan State University...., NW., Washington, DC. Docket Number: 10-043. Applicant: National Superconducting Cyclotron Laboratory...
Energy Technology Data Exchange (ETDEWEB)
Bhattacharjee, Tanushyam; Kanti Dey, Malay; Dhara, Partha; Roy, Suvodeep; Debnath, Jayanta; Balakrishna Bhole, Rajendra; Dutta, Atanu; Pradhan, Jedidiah; Pal, Sarbajit; Pal, Gautam; Roy, Amitava; Chakrabarti, Alok [Variable Energy Cyclotron Centre, 1/AF Bidhannagar, Kolkata 700064 (India)
2013-05-15
In an isochronous cyclotron, measurements of central phase of the ion beam with respect to rf and the phase width provide a way to tune the cyclotron for maximum energy gain per turn and efficient extraction. We report here the development of a phase measurement system and the measurements carried out at the Variable Energy Cyclotron Centre's (VECC's) K= 500 superconducting cyclotron. The technique comprises detecting prompt {gamma}-rays resulting from the interaction of cyclotron ion beam with an aluminium target mounted on a radial probe in coincidence with cyclotron rf. An assembly comprising a fast scintillator and a liquid light-guide inserted inside the cyclotron was used to detect the {gamma}-rays and to transfer the light signal outside the cyclotron where a matching photo-multiplier tube was used for light to electrical signal conversion. The typical beam intensity for this measurement was a few times 10{sup 11} pps.
Martínez-Serrano, J Javier; Díez de los Ríos, Antonio
2010-11-01
The authors want to assess the relevance of the neutron activation of the concrete vault of the PET cyclotron at CIMES (Universidad de Malaga) by predicting specific activities of the main activation products in the vault and their variation profiles as a function of penetration depth into concrete at present and after 10 yr of cyclotron operation. The dual proton cyclotron is used for PET isotopes production, mainly 18F. During the years 2006 and 2008, the using rate has been 1 h/day at single beam (40 microA). From January 2008, using rate is 4 h/day at dual beam (80 microA). The energy of the cyclotron proton beam is 18 MeV. Four point locations were chosen on the walls of the cyclotron room to assess neutron induced activity concentrations. In each wall point location, neutron induced radionuclide specific activity was assessed from the wall surface to a depth of 120 cm within concrete. Simulations were carried out with the Monte Carlo based radiation transport code MCNPX (v2.6.0). According to MCNPX calculations, activity depth profiles of activation products studied, except 54Mn, have a maximum at variable depths from the wall surface never beyond 12 cm. 54Mn activity decreases exponentially in all the studied depth ranges within wall concrete. The activity of 152Eu, 154Eu, 60CO, 134Cs, 46Sc, and 65Zn decreases exponentially beyond a 30 cm depth into concrete. 54Mn activity presents the faster decrease within a concrete vault with an attenuation length of 21 cm. According to MCNPX estimations, present activity in the cyclotron vault is mostly due to 46Sc and 60Co, with highest specific activity near the vault surface of 146 +/- 16 and 50 +/- 4.6 Bq/kg, respectively. 46Sc and 60Co activity measurements near the surface wall present an acceptable match with the estimation within the uncertainties, but measured activities of the other radionuclides are quite over the MCNPX estimations. The calculations after 10 yr of cyclotron operation predict a slight increase
Foundations of radiation hydrodynamics
Mihalas, D.; Mihalas, B. W.
This book is the result of an attempt, over the past few years, to gather the basic tools required to do research on radiating flows in astrophysics. The microphysics of gases is discussed, taking into account the equation of state of a perfect gas, the first and second law of thermodynamics, the thermal properties of a perfect gas, the distribution function and Boltzmann's equation, the collision integral, the Maxwellian velocity distribution, Boltzmann's H-theorem, the time of relaxation, and aspects of classical statistical mechanics. Other subjects explored are related to the dynamics of ideal fluids, the dynamics of viscous and heat-conducting fluids, relativistic fluid flow, waves, shocks, winds, radiation and radiative transfer, the equations of radiation hydrodynamics, and radiating flows. Attention is given to small-amplitude disturbances, nonlinear flows, the interaction of radiation and matter, the solution of the transfer equation, acoustic waves, acoustic-gravity waves, basic concepts of special relativity, and equations of motion and energy.
Radiation therapy services in South Africa
African Journals Online (AJOL)
mum electron energy capacity greater than 10 MEV. Nine machines have a maximum photon energy capa- city below 10 MEV (Table I). A cyclotron-based 66. MEV neutron therapy machine used as a national faci- lity is based in the Cape. TABLE I. Megavoltage radiation therapy units in South Africa. Photon. Electron.
The Los Alamos suite of relativistic atomic physics codes
Fontes, C. J.; Zhang, H. L.; Abdallah, J., Jr.; Clark, R. E. H.; Kilcrease, D. P.; Colgan, J.; Cunningham, R. T.; Hakel, P.; Magee, N. H.; Sherrill, M. E.
2015-07-01
The Los Alamos suite of relativistic atomic physics codes is a robust, mature platform that has been used to model highly charged ions in a variety of ways. The suite includes capabilities for calculating data related to fundamental atomic structure, as well as the processes of photoexcitation, electron-impact excitation and ionization, photoionization and autoionization within a consistent framework. These data can be of a basic nature, such as cross sections and collision strengths, which are useful in making predictions that can be compared with experiments to test fundamental theories of highly charged ions, such as quantum electrodynamics. The suite can also be used to generate detailed models of energy levels and rate coefficients, and to apply them in the collisional-radiative modeling of plasmas over a wide range of conditions. Such modeling is useful, for example, in the interpretation of spectra generated by a variety of plasmas. In this work, we provide a brief overview of the capabilities within the Los Alamos relativistic suite along with some examples of its application to the modeling of highly charged ions.
Energy Technology Data Exchange (ETDEWEB)
Alberdi, A.; Gomez, J.L.; Marcaide, J.M.
1993-01-01
We have developed a numerical code which solves the synchrotron radiation transfer equations to compute the total and polarized emission of bent shocked relativistic jets, and we have applied it to reproduce the compact structure, kinematic evolution of the superluminal radio source 4C 39.25 contains a bent relativistic jet which is misaligned relative to the observer near the core region, leading to a relatively low core brightness. (Author) 12 refs.
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.
Cyclotron instabilities driven by temperature anisotropy in the solar wind
Noreen, N.; Yoon, P. H.; Zaheer, S.
2017-10-01
Kinetic plasma instabilities are important for regulating the temperature anisotropies of electrons and ions in solar wind. For the low beta regime, it is known that electromagnetic ion/electron cyclotron instabilities are important, but in the literature these unstable modes are discussed under the assumption of parallel propagation. The present paper extends the analysis to two (or with cylindrical symmetry, three) dimensions. The analysis is further extended to include quasilinear description with the assumption of the bi-Maxwellian velocity distribution function. Such an analysis lays the foundation for an eventual study in which cyclotron instabilities as well as obliquely propagating unstable modes such as the mirror instability are simultaneously taken into account. The present paper first lays down the basis for such future efforts in which the two- or three dimensional linear and quasilinear theories of cyclotron instabilities in the low beta regime are formulated.
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.
Project: Modeling Relativistic Electrons from Nuclear Explosions in the Magnetosphere
Energy Technology Data Exchange (ETDEWEB)
Cowee, Misa [Los Alamos National Laboratory; Gary, S. Peter [Los Alamos National Laboratory; Winske, Dan [Los Alamos National Laboratory; Liu, Kaijun [Los Alamos National Laboratory
2012-07-17
We present a summary of the FY12 activities for DTRA-funded project 'Modeling Relativistic Electrons from Nuclear Explosions in the Magnetosphere'. We briefly review the outstanding scientific questions and discuss the work done in the last year to try to answer these questions. We then discuss the agenda for this Technical Meeting with the DTRA sponsors. In the last year, we have continued our efforts to understand artificial radiation belts from several different perspectives: (1) Continued development of Electron Source Model (ESM) and comparison to HANE test data; (2) Continued studies of relativistic electron scattering by waves in the natural radiation belts; (3) Began study of self-generated waves from the HANE electrons; and (4) Began modeling for the UCLA laser experiment.
Distribution of thermal neutron flux around a PET cyclotron.
Ogata, Yoshimune; Ishigure, Nobuhito; Mochizuki, Shingo; Ito, Kengo; Hatano, Kentaro; Abe, Junichiro; Miyahara, Hiroshi; Masumoto, Kazuyoshi; Nakamura, Hajime
2011-05-01
The number of positron emission tomography (PET) examinations has greatly increased world-wide. Since positron emission nuclides for the PET examinations have short half-lives, they are mainly produced using on-site cyclotrons. During the production of the nuclides, significant quantities of neutrons are generated from the cyclotrons. Neutrons have potential to activate the materials around the cyclotrons and cause exposure to the staff. To investigate quantities and distribution of the thermal neutrons, thermal neutron fluxes were measured around a PET cyclotron in a laboratory associating with a hospital. The cyclotron accelerates protons up to 18 MeV, and the mean particle current is 20 μA. The neutron fluxes were measured during both 18F production and C production. Gold foils and thermoluminescent dosimeter (TLD) badges were used to measure the neutron fluxes. The neutron fluxes in the target box averaged 9.3 × 10(6) cm(-2) s(-1) and 1.7 × 10(6) cm(-2) s(-1) during 18F and 11C production, respectively. Those in the cyclotron room averaged 4.1 × 10(5) cm(-2) s(-1) and 1.2 × 10(5) cm(-2) s(-1), respectively. Those outside the concrete wall shielding were estimated as being equal to or less than ∼3 cm s, which corresponded to 0.1 μSv h(-1) in effective dose. The neutron fluxes outside the concrete shielding were confirmed to be quite low compared to the legal limit.
Alba, David; Crater, Horace W.; Lusanna, Luca
2015-03-01
A new formulation of relativistic classical mechanics allows a reconsideration of old unsolved problems in relativistic kinetic theory and in relativistic statistical mechanics. In particular a definition of the relativistic micro-canonical partition function is given strictly in terms of the Poincaré generators of an interacting N-particle system both in the inertial and non-inertial rest frames. The non-relativistic limit allows a definition of both the inertial and non-inertial micro-canonical ensemble in terms of the Galilei generators.
Chaos and maps in relativistic rynamical systems
Directory of Open Access Journals (Sweden)
L. P. Horwitz
2000-01-01
Full Text Available 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 “mass” of the interacting electromagnetic field, provides a consistent system of classical equations for describing such processes.
Relativistic mixtures of charged and uncharged particles
Energy Technology Data Exchange (ETDEWEB)
Kremer, Gilberto M. [Departamento de Física, Universidade Federal do Paraná, Curitiba (Brazil)
2014-01-14
Mixtures of relativistic gases within the framework of Boltzmann equation are analyzed. Three systems are considered. The first one refers to a mixture of uncharged particles by using Grad’s moment method, where the relativistic mixture is characterized by the moments of the distribution functions: particle four-flows, energy-momentum tensors, and third-order moment tensors. In the second Fick’s law for a mixture of relativistic gases of non-disparate rest masses in a Schwarzschild metric are derived from an extension of Marle and McCormack model equations applied to a relativistic truncated Grad’s distribution function, where it is shown the dependence of the diffusion coefficient on the gravitational potential. The third one consists in the derivation of the relativistic laws of Ohm and Fourier for a binary mixtures of electrons with protons and electrons with photons subjected to external electromagnetic fields and in presence of gravitational fields by using the Anderson and Witting model of the Boltzmann equation.
Compton Sources of Electromagnetic Radiation
Energy Technology Data Exchange (ETDEWEB)
Geoffrey Krafft,Gerd Priebe
2011-01-01
When a relativistic electron beam interacts with a high-field laser beam, intense and highly collimated electromagnetic radiation will be generated through Compton scattering. Through relativistic upshifting and the relativistic Doppler effect, highly energetic polarized photons are radiated along the electron beam motion when the electrons interact with the laser light. For example, X-ray radiation can be obtained when optical lasers are scattered from electrons of tens-of-MeV beam energy. Because of the desirable properties of the radiation produced, many groups around the world have been designing, building, and utilizing Compton sources for a wide variety of purposes. In this review article, we discuss the generation and properties of the scattered radiation, the types of Compton source devices that have been constructed to date, and the prospects of radiation sources of this general type. Due to the possibilities of producing hard electromagnetic radiation in a device that is small compared to the alternative storage ring sources, it is foreseen that large numbers of such sources may be constructed in the future.
Relativistic 2-body Bottomonium decays
Directory of Open Access Journals (Sweden)
Barducci Andrea
2017-01-01
Full Text Available We calculate some radiative decays of Bottomonium in a covariant scheme for two interacting fermions. We present their branching ratios and their absolute widths. A comparison with experimental data shows a good agreement with our results. Some decays for which data are not available are compared with other theoretical previsions.
General relativistic weak-field limit and Newtonian N-body simulations
Fidler, Christian; Tram, Thomas; Rampf, Cornelius; Crittenden, Robert; Koyama, Kazuya; Wands, David
2017-12-01
We show how standard Newtonian N-body simulations can be interpreted in terms of the weak-field limit of general relativity by employing the recently developed Newtonian motion gauge. Our framework allows the inclusion of radiation perturbations and the non-linear evolution of matter. We show how to construct the weak-field metric by combining Newtonian simulations with results from Einstein-Boltzmann codes. We discuss observational effects on weak lensing and ray tracing, identifying important relativistic corrections.
Wave-driven butterfly distribution of Van Allen belt relativistic electrons
Xiao, Fuliang; Yang, Chang; Su, Zhenpeng; Zhou, Qinghua; He, Zhaoguo; He, Yihua; Baker, D. N.; Spence, H. E.; Funsten, H. O.; Blake, J. B.
2015-01-01
Van Allen radiation belts consist of relativistic electrons trapped by Earth's magnetic field. Trapped electrons often drift azimuthally around Earth and display a butterfly pitch angle distribution of a minimum at 90° further out than geostationary orbit. This is usually attributed to drift shell splitting resulting from day–night asymmetry in Earth's magnetic field. However, direct observation of a butterfly distribution well inside of geostationary orbit and the origin of this phenomenon h...
Signatures of Dark Radiation in Neutrino and Dark Matter Detectors
Cui, Yanou; Pospelov, Maxim; Pradler, Josef
2017-01-01
We consider the generic possibility that the Universe's energy budget includes some form of relativistic or semi-relativistic dark radiation (DR) with non-gravitational interactions with Standard Model (SM) particles. Such dark radiation may consist of SM singlets or a non-thermal, energetic component of neutrinos. If such DR is created at a relatively recent epoch, it can carry sufficient energy to leave a detectable imprint in experiments designed to search for very weakly interacting parti...
Transverse electron-scale instability in relativistic shear flows
Alves, E P; Fonseca, R A; Silva, L O
2015-01-01
Electron-scale surface waves are shown to be unstable in the transverse plane of a shear flow in an initially unmagnetized plasma, unlike in the (magneto)hydrodynamics case. It is found that these unstable modes have a higher growth rate than the closely related electron-scale Kelvin-Helmholtz instability in relativistic shears. Multidimensional particle-in-cell simulations verify the analytic results and further reveal the emergence of mushroom-like electron density structures in the nonlinear phase of the instability, similar to those observed in the Rayleigh Taylor instability despite the great disparity in scales and different underlying physics. Macroscopic ($\\gg c/\\omega_{pe}$) fields are shown to be generated by these microscopic shear instabilities, which are relevant for particle acceleration, radiation emission and to seed MHD processes at long time-scales.
Relativistic Scott correction for atoms and molecules
DEFF Research Database (Denmark)
Solovej, Jan Philip; Sørensen, Thomas Østergaard; Spitzer, Wolfgang Ludwig
2010-01-01
We prove the first correction to the leading Thomas-Fermi energy for the ground state energy of atoms and molecules in a model where the kinetic energy of the electrons is treated relativistically. The leading Thomas-Fermi energy, established in [25], as well as the correction given here, are of ......We prove the first correction to the leading Thomas-Fermi energy for the ground state energy of atoms and molecules in a model where the kinetic energy of the electrons is treated relativistically. The leading Thomas-Fermi energy, established in [25], as well as the correction given here......, are of semiclassical nature. Our result on atoms and molecules is proved from a general semiclassical estimate for relativistic operators with potentials with Coulomb-like singularities. This semiclassical estimate is obtained using the coherent state calculus introduced in [36]. The paper contains a unified treatment...
Anisotropic Particle Acceleration in Relativistic Shear Layers
Boettcher, Markus; Liang, Edison P.; Fu, Wen
2017-08-01
We present results of Particle in Cell (PIC) simulations of relativistic shear layers as relevant to the relativistic jets of acive galactic nuclei and gamma-ray bursts. We study the self-generation of electro-magnetic fields and particle acceleration for various different plasma compositions (electron-ion vs. electron-positron pair vs. hybrid). Special emphasis is placed on the angular distribution of accelerated particles. We find that electron-ion shear layers lead to highly anisotropic particle distributions in the frame of the fast-moving inner spine. The beaming pattern of the highest-energy particles is much narrower than the characteristic beaming angle of 1/Gamma resulting from relativistic aberration of a co-moving isotropic distribution. This may pose a possible solution to the Lorentz-Factor crisis in blazars and explain very hard X-ray / soft gamma-ray spectra of some gamma-ray bursts.
Exact quantisation of the relativistic Hopfield model
Energy Technology Data Exchange (ETDEWEB)
Belgiorno, F., E-mail: francesco.belgiorno@polimi.it [Dipartimento di Matematica, Politecnico di Milano, Piazza Leonardo 32, IT-20133 Milano (Italy); INdAM-GNFM (Italy); Cacciatori, S.L., E-mail: sergio.cacciatori@uninsubria.it [Department of Science and High Technology, Università dell’Insubria, Via Valleggio 11, IT-22100 Como (Italy); INFN sezione di Milano, via Celoria 16, IT-20133 Milano (Italy); Dalla Piazza, F., E-mail: f.dallapiazza@gmail.com [Università “La Sapienza”, Dipartimento di Matematica, Piazzale A. Moro 2, I-00185, Roma (Italy); Doronzo, M., E-mail: m.doronzo@uninsubria.it [Department of Science and High Technology, Università dell’Insubria, Via Valleggio 11, IT-22100 Como (Italy)
2016-11-15
We investigate the quantisation in the Heisenberg representation of a relativistically covariant version of the Hopfield model for dielectric media, which entails the interaction of the quantum electromagnetic field with the matter dipole fields, represented by a mesoscopic polarisation field. A full quantisation of the model is provided in a covariant gauge, with the aim of maintaining explicit relativistic covariance. Breaking of the Lorentz invariance due to the intrinsic presence in the model of a preferred reference frame is also taken into account. Relativistic covariance forces us to deal with the unphysical (scalar and longitudinal) components of the fields, furthermore it introduces, in a more tricky form, the well-known dipole ghost of standard QED in a covariant gauge. In order to correctly dispose of this contribution, we implement a generalised Lautrup trick. Furthermore, causality and the relation of the model with the Wightman axioms are also discussed.
Nonlinear relativistic plasma resonance: Renormalization group approach
Energy Technology Data Exchange (ETDEWEB)
Metelskii, I. I., E-mail: metelski@lebedev.ru [Russian Academy of Sciences, Lebedev Physical Institute (Russian Federation); Kovalev, V. F., E-mail: vfkvvfkv@gmail.com [Dukhov All-Russian Research Institute of Automatics (Russian Federation); Bychenkov, V. Yu., E-mail: bychenk@lebedev.ru [Russian Academy of Sciences, Lebedev Physical Institute (Russian Federation)
2017-02-15
An analytical solution to the nonlinear set of equations describing the electron dynamics and electric field structure in the vicinity of the critical density in a nonuniform plasma is constructed using the renormalization group approach with allowance for relativistic effects of electron motion. It is demonstrated that the obtained solution describes two regimes of plasma oscillations in the vicinity of the plasma resonance— stationary and nonstationary. For the stationary regime, the spatiotemporal and spectral characteristics of the resonantly enhanced electric field are investigated in detail and the effect of the relativistic nonlinearity on the spatial localization of the energy of the plasma relativistic field is considered. The applicability limits of the obtained solution, which are determined by the conditions of plasma wave breaking in the vicinity of the resonance, are established and analyzed in detail for typical laser and plasma parameters. The applicability limits of the earlier developed nonrelativistic theories are refined.
Vilkov, M. N.; Ginzburg, N. S.; Denisov, G. G.; Zotova, I. V.; Sergeev, A. S.
2016-01-01
We demonstrate the possibility of forming a periodic series of ultra-short pulses, which has a peak power exceeding significantly the radiation power in stationary regimes, in a gyroresonance traveling-wave tube (gyro-TWT) with a bleachable cyclotron absorber in the feedback circuit. The mechanism of pulsed generation is similar to the method of passive mode locking, which is used widely in laser physics.
Microwave power coupling with electron cyclotron resonance ...
Indian Academy of Sciences (India)
The effect of microwave power coupling to the plasma was studied by varying the microwave power. ... plasma is produced by the interaction of microwave radiation, in the presence of appro- priate magnetic field ... microwaves are used in resonant mode to couple the electromagnetic energy to the plasma for generating ...
Idei, H.; Mishra, K.; Yamamoto, M. K.; Hamasaki, M.; Fujisawa, A.; Nagashima, Y.; Hayashi, Y.; Onchi, T.; Hanada, K.; Zushi, H.; the QUEST Team
2016-04-01
Measurement of the Electron Cyclotron Emission (ECE) spectrum is one of the most popular electron temperature diagnostics in nuclear fusion plasma research. A 2-dimensional ECE imaging system was developed with an adaptive-array approach. A radio-frequency (RF) heterodyne detection system with Software Defined Radio (SDR) devices and a phased-array receiver antenna was used to measure the phase and amplitude of the ECE wave. The SDR heterodyne system could continuously measure the phase and amplitude with sufficient accuracy and time resolution while the previous digitizer system could only acquire data at specific times. Robust streaming phase measurements for adaptive-arrayed continuous ECE diagnostics were demonstrated using Fast Fourier Transform (FFT) analysis with the SDR system. The emission field pattern was reconstructed using adaptive-array analysis. The reconstructed profiles were discussed using profiles calculated from coherent single-frequency radiation from the phase array antenna.
Rowan, W L; Houshmandyar, S; Phillips, P E; Austin, M E; Beno, J H; Hubbard, A E; Khodak, A; Ouroua, A; Taylor, G
2016-11-01
Measurement of the electron cyclotron emission (ECE) is one of the primary diagnostics for electron temperature in ITER. In-vessel, in-vacuum, and quasi-optical antennas capture sufficient ECE to achieve large signal to noise with microsecond temporal resolution and high spatial resolution while maintaining polarization fidelity. Two similar systems are required. One views the plasma radially. The other is an oblique view. Both views can be used to measure the electron temperature, while the oblique is also sensitive to non-thermal distortion in the bulk electron distribution. The in-vacuum optics for both systems are subject to degradation as they have a direct view of the ITER plasma and will not be accessible for cleaning or replacement for extended periods. Blackbody radiation sources are provided for in situ calibration.
Study on the electron-cyclotron-emission diagnostics on JT-60U
Energy Technology Data Exchange (ETDEWEB)
Hwang, Cheol Kyu [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)
1996-09-01
Diagnostic system for electron cyclotron emission(ECE) in JT-60 have been surveyed. At JT-60 there are three different ECE-systems: a Fourier transformed spectroscopy system(FTS), a grating polycromater system(GPS), and a heterodyne radiometer system(HRS). Each of the systems has been examined to understand the instrumental feature with much attention to the sensitivity and the resolution. FTS has been studied with particular interest because of its continuous and wide spectral coverage and reliable characteristics for calibration. Some topics in instrumentation for FTS are discussed to get an insight on the system specifications optimal for tokamak experiments. Finally, experimental results of FTS with black body radiation at liquid-nitrogen temperature are described in connection with the calibration of the light guiding system for ECE from JT-60 plasma. 14 refs. (Author).
Relativistic parsec-scale jets: II. Synchrotron emission
Pariev, V. I.; Istomin, Ya. N.; Beresnyak, A. R.
2003-06-01
We calculate the optically thin synchrotron emission of fast electrons and positrons in a spiral stationary magnetic field and a radial electric field of a rotating relativistic strongly magnetized force-free jet consisting of electron-positron pair plasma. The magnetic field has a helical structure with a uniform axial component and a toroidal component that is maximal inside the jet and decreasing to zero towards the boundary of the jet. Doppler boosting and swing of the polarization angle of synchrotron emission due to the relativistic motion of the emitting volume are calculated. The distribution of the plasma velocity in the jet is consistent with the electromagnetic field structure. Two spatial distributions of fast particles are considered: uniform, and concentrated in the vicinity of the Alfvén resonance surface. The latter distribution corresponds to the regular acceleration by an electromagnetic wave in the vicinity of its Alfvén resonance surface inside the jet. The polarization properties of the radiation have been obtained and compared with the existing VLBI polarization measurements of parsec-scale jets in BL Lac sources and quasars. Our results give a natural explanation of the observed bimodality in the alignment between the electric field vector of the polarized radiation and the projection of the jet axis on the plane of the sky. We interpret the motion of bright knots as a phase velocity of standing spiral eigenmodes of electromagnetic perturbations in a cylindrical jet. The degree of polarization and the velocity of the observed proper motion of bright knots depend upon the angular rotational velocity of the jet. The observed polarizations and velocities of knots indicate that the magnetic field lines are bent in the direction opposite to the direction of the jet rotation.
General relativistic tidal heating for Moller pseudotensor
So, Lau Loi
2015-01-01
Thorne elucidated that the relativistic tidal heating is the same as the Newtonian theory. Moreover, Thorne also claimed that the tidal heating is independent of how one localizes gravitational energy and is unambiguously given by a certain formula. Purdue and Favata calculated the tidal heating for different classical pseudotensors including Moller and obtained the results all matched with the Newtonian perspective. After re-examined this Moller pseudotensor, we find that there does not exist any tidal heating value. Thus we claim that the relativistic tidal heating is pseudotensor independent under the condition that if the peusdotensor is a Freud typed superpotential.
Relativistic quantum mechanics of a Dirac oscillator
Martines y Romero, R P; Salas-Brito, A L
1995-01-01
The Dirac oscillator is an exactly soluble model recently introduced in the context of many particle models in relativistic quantum mechanics. The model has been also considered as an interaction term for modelling quark confinement in quantum chromodynamics. These considerations should be enough for demonstrating that the Dirac oscillator can be an excellent example in relativistic quantum mechanics. In this paper we offer a solution to the problem and discuss some of its properties. We also discuss a physical picture for the Dirac oscillator's non-standard interaction, showing how it arises on describing the behaviour of a neutral particle carrying an anomalous magnetic moment and moving inside a uniformly charged sphere. (author)
Fermi Acceleration in driven relativistic billiards
Energy Technology Data Exchange (ETDEWEB)
Pinto, Rafael S., E-mail: rsoaresp@ifi.unicamp.br [Instituto de Fisica ' Gleb Wataghin' , Universidade Estadual de Campinas, 13083-970, Campinas, SP (Brazil); Letelier, Patricio S. [Departamento de Matematica Aplicada, Instituto de Matematica, Estatistica e Computacao Cientifica, Universidade Estadual de Campinas, 13083-859, Campinas, SP (Brazil)
2011-08-29
We show numerical experiments of driven billiards using special relativity. We have the remarkable fact that for the relativistic driven circular and annular concentric billiards, depending on initial conditions and parameters, we observe Fermi Acceleration, absent in the Newtonian case. The velocity for these cases tends to the speed of light very quickly. We find that for the annular eccentric billiard the initial velocity grows for a much longer time than the concentric annular billiard until it asymptotically reach c. -- Highlights: → Fermi Acceleration is studied for relativistic driven billiards. → We studied regular and chaotic billiards with different parameters. → Fermi Acceleration is present even for static regular billiards.
Level density parameter in relativistic models
Energy Technology Data Exchange (ETDEWEB)
Centelles, M. (Dept. d' Estructura i Constituents de la Materia, Facultat de Fisica, Univ. de Barcelona (Spain)); Vinas, X. (Dept. d' Estructura i Constituents de la Materia, Facultat de Fisica, Univ. de Barcelona (Spain)); Schuck, P. (Inst. des Sciences Nucleaires, 38 Grenoble (France))
1994-01-24
The level density parameter for finite nuclei is studied in the framework of the relativistic mean field theory. Systematic self-consistent calculations are performed in the Thomas-Fermi approximation using [sigma]-[omega] models that include scalar meson self-couplings. For realistic nuclear matter properties, the level density parameter turns out to be in the range of values obtained in non-relativistic calculations with Skyrme interactions, and thus it is smaller than the global trend of the experimental data. The implications for the level density parameter of including vacuum fluctuations and exchange corrections in the mean field theory are also investigated. (orig.)
Relativistic Celestial Mechanics of the Solar System
Kopeikin, Sergei; Kaplan, George
2011-01-01
This authoritative book presents the theoretical development of gravitational physics as it applies to the dynamics of celestial bodies and the analysis of precise astronomical observations. In so doing, it fills the need for a textbook that teaches modern dynamical astronomy with a strong emphasis on the relativistic aspects of the subject produced by the curved geometry of four-dimensional spacetime. The first three chapters review the fundamental principles of celestial mechanics and of special and general relativity. This background material forms the basis for understanding relativistic r