Cosmic censorship, black holes, and particle orbits
International Nuclear Information System (INIS)
Hiscock, W.A.
1979-01-01
One of the main reasons for believing in the cosmic censorship hypothesis is the disquieting nature of the alternative: the existence of naked singularities, and hence loss of predictability, the possibility of closed timelike lines and so forth. The consequences of assuming the cosmic hypothesis can also be somewhat strange and unexpected. In particular, Hawking's black hole area theorem is applied to the study of particle orbits near a Schwarzschild black hole. If the cosmic censorship hypothesis (and hence the area theorem) is true, then there exist stable near-circular orbits arbitrarily close to the horizon at r = 2M. (author)
International Nuclear Information System (INIS)
Fujisawa, Takashi; Hattori, Toshiyuki
2006-01-01
One of the present inventions provides a spiral orbit charged particle accelerator in which the magnetic field increases as the radius increases more rapidly than an isochronous magnetic field distribution, and the distribution of fixed-frequency accelerating RF voltage is formed so that a harmonic number changes in integer for every particle revolution. The other invention realizes to make the closed orbit charged particle accelerator having a fixed frequency amplitude modulator that is able to modulate amplitude of the RF voltage so that a harmonic number decreases in integer in an every particle revolution. (author)
Effects of solar radiation on the orbits of small particles
Lyttleton, R. A.
1976-01-01
A modification of the Robertson (1937) equations of particle motion in the presence of solar radiation is developed which allows for partial reflection of sunlight as a result of rapid and varying particle rotations caused by interaction with the solar wind. The coefficients and forces in earlier forms of the equations are compared with those in the present equations, and secular rates of change of particle orbital elements are determined. Orbital dimensions are calculated in terms of time, probable sizes and densities of meteoric and cometary particles are estimated, and times of infall to the sun are computed for a particle moving in an almost circular orbit and a particle moving in an elliptical orbit of high eccentricity. Changes in orbital elements are also determined for particles from a long-period sun-grazing comet. The results show that the time of infall to the sun from a highly eccentric orbit is substantially shorter than from a circular orbit with a radius equal to the mean distance in the eccentric orbit. The possibility is considered that the free orbital kinetic energy of particles drawn into the sun may be the energy source for the solar corona.
Dyson Orbitals, Quasi-Particle effects and Compton scattering
Barbiellini, B.; Bansil, A.
2004-01-01
Dyson orbitals play an important role in understanding quasi-particle effects in the correlated ground state of a many-particle system and are relevant for describing the Compton scattering cross section beyond the frameworks of the impulse approximation (IA) and the independent particle model (IPM). Here we discuss corrections to the Kohn-Sham energies due to quasi-particle effects in terms of Dyson orbitals and obtain a relatively simple local form of the exchange-correlation energy. Illust...
Stochastic behaviour of particle orbits in field reversed geometries
International Nuclear Information System (INIS)
Finn, J.M.
1979-01-01
Studies of stochastic or ergodic behaviour of beam particle orbits in axisymmetric systems with field reversal produced by ion rings or by neutral injection are presented. In the former case a large class of orbits is ergodic, whereas in the latter most are integrable. Effects of ergodic behaviour on particle confinement, equilibrium, magnetic compression, and stability are discussed. The modification, due to ergodic orbits of the stability criterion for low frequency (ω << ωsub(ci)) resonant instabilities is presented. (author)
Periodic orbits near the particle resonance in galaxies
Contopoulos, George
1978-01-01
Near the particle resonance of a spiral galaxy the almost circular periodic orbits that exist inside the resonance (direct) or outside it (retrograde) are replaced by elongated trapped orbits around the maxima of the potential L/sub 4/ and L/sub 5/. These are the long- period trapped periodic orbits. The long-period orbits shrink to the points L/sub 4/, L/sub 5/ for a critical value of the Hamiltonian h. For still larger h, a family of short-period trapped orbits appears, with continuously growing size. The evolution of the periodic orbits with h is followed, theoretically and numerically, from the untrapped orbits to the long-periodic orbits and then to the short-periodic orbits, mainly in the case of a bar. In a tight spiral case an explanation of the asymmetric periodic and banana orbits is given, and an example of short-period orbits not surrounding L/sub 4/ or L/sub 5/ is provided. Another family of periodic orbits reaching corotation is trapped at the inner Lindblad resonance. (5 refs).
Full particle orbit effects in regular and stochastic magnetic fields
Energy Technology Data Exchange (ETDEWEB)
Ogawa, Shun, E-mail: shun.ogawa@cpt.univ-mrs.fr [Aix Marseille Univ., Univ. Toulon, CNRS, CPT, Marseille (France); CEA, IRFM, F-13108 St. Paul-lez-Durance Cedex (France); Cambon, Benjamin; Leoncini, Xavier; Vittot, Michel [Aix Marseille Univ., Univ. Toulon, CNRS, CPT, Marseille (France); Castillo-Negrete, Diego del [Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6169 (United States); Dif-Pradalier, Guilhem; Garbet, Xavier [CEA, IRFM, F-13108 St. Paul-lez-Durance Cedex (France)
2016-07-15
We present a numerical study of charged particle motion in a time-independent magnetic field in cylindrical geometry. The magnetic field model consists of an unperturbed reversed-shear (non-monotonic q-profile) helical part and a perturbation consisting of a superposition of modes. Contrary to most of the previous studies, the particle trajectories are computed by directly solving the full Lorentz force equations of motion in a six-dimensional phase space using a sixth-order, implicit, symplectic Gauss-Legendre method. The level of stochasticity in the particle orbits is diagnosed using averaged, effective Poincare sections. It is shown that when only one mode is present, the particle orbits can be stochastic even though the magnetic field line orbits are not stochastic (i.e., fully integrable). The lack of integrability of the particle orbits in this case is related to separatrix crossing and the breakdown of the global conservation of the magnetic moment. Some perturbation consisting of two modes creates resonance overlapping, leading to Hamiltonian chaos in magnetic field lines. Then, the particle orbits exhibit a nontrivial dynamics depending on their energy and pitch angle. It is shown that the regions where the particle motion is stochastic decrease as the energy increases. The non-monotonicity of the q-profile implies the existence of magnetic ITBs (internal transport barriers) which correspond to shearless flux surfaces located in the vicinity of the q-profile minimum. It is shown that depending on the energy, these magnetic ITBs might or might not confine particles. That is, magnetic ITBs act as an energy-dependent particle confinement filter. Magnetic field lines in reversed-shear configurations exhibit topological bifurcations (from homoclinic to heteroclinic) due to separatrix reconnection. We show that a similar but more complex scenario appears in the case of particle orbits that depend in a non-trivial way on the energy and pitch angle of the
Quantum walks and orbital states of a Weyl particle
International Nuclear Information System (INIS)
Katori, Makoto; Fujino, Soichi; Konno, Norio
2005-01-01
The time-evolution equation of a one-dimensional quantum walker is exactly mapped to the three-dimensional Weyl equation for a zero-mass particle with spin 1/2, in which each wave number k of the walker's wave function is mapped to a point q(k) in the three-dimensional momentum space and q(k) makes a planar orbit as k changes its value in [-π,π). The integration over k providing the real-space wave function for a quantum walker corresponds to considering an orbital state of a Weyl particle, which is defined as a superposition (curvilinear integration) of the energy-momentum eigenstates of a free Weyl equation along the orbit. Konno's novel distribution function of a quantum walker's pseudovelocities in the long-time limit is fully controlled by the shape of the orbit and how the orbit is embedded in the three-dimensional momentum space. The family of orbital states can be regarded as a geometrical representation of the unitary group U(2) and the present study will propose a new group-theoretical point of view for quantum-walk problems
Particle orbits in W VII-X configurations
International Nuclear Information System (INIS)
Wobig, H.
1987-01-01
It is shown that magnetic coordinates are very convenient for describing particle orbits and neoclassical losses in stellarator studies. In the configurations considered (WVII-A and AS, Helias, Heliac, and BSX) plateau losses can be reduced by a factor of 3-4 compared with an equivalent tokamak. It is possible to reduce plateau losses and bootstrap current simultaneously. The bootstrap current can be made negligibly small. The Heliac configuration shows larger plateau losses than the equivalent tokamak. It is possible to localize trapped particles in a region of minimum radial drift velocity. The Er fields strongly reduce localized particle losses
Directing orbits of chaotic systems by particle swarm optimization
International Nuclear Information System (INIS)
Liu Bo; Wang Ling; Jin Yihui; Tang Fang; Huang Dexian
2006-01-01
This paper applies a novel evolutionary computation algorithm named particle swarm optimization (PSO) to direct the orbits of discrete chaotic dynamical systems towards desired target region within a short time by adding only small bounded perturbations, which could be formulated as a multi-modal numerical optimization problem with high dimension. Moreover, the synchronization of chaotic systems is also studied, which can be dealt with as an online problem of directing orbits. Numerical simulations based on Henon Map demonstrate the effectiveness and efficiency of PSO, and the effects of some parameters are also investigated
Stability of large orbit, high-current particle rings
International Nuclear Information System (INIS)
Lovelace, R.V.E.
1994-01-01
A review is made of theory of the low-frequency stability of large orbit, high-current particle rings which continue to be of interest for compact fusion systems. The precession mode was the first mode predicted by Furth and observed by Christofilos to be unstable under certain conditions. Subsequently, many detailed studies have been made of the stability of particle rings- different modes, different ring geometries, systems with/without a toroidal B field, and sytems with/without a current carrying plasma component. The possibly dangerous modes are still thought to include the precession mode, the tilting mode, and the low order kink modes. copyright American Institute of Physics
Particle orbit tracking on a parallel computer: Hypertrack
International Nuclear Information System (INIS)
Cole, B.; Bourianoff, G.; Pilat, F.; Talman, R.
1991-05-01
A program has been written which performs particle orbit tracking on the Intel iPSC/860 distributed memory parallel computer. The tracking is performed using a thin element approach. A brief description of the structure and performance of the code is presented, along with applications of the code to the analysis of accelerator lattices for the SSC. The concept of ''ensemble tracking'', i.e. the tracking of ensemble averages of noninteracting particles, such as the emittance, is presented. Preliminary results of such studies will be presented. 2 refs., 6 figs
Finite orbit energetic particle linear response to toroidal Alfven eigenmodes
International Nuclear Information System (INIS)
Berk, H.L.; Ye, Huanchun; Breizman, B.N.
1991-07-01
The linear response of energetic particles to the TAE modes is calculated taking into account their finite orbit excursion from the flux surfaces. The general expression reproduces the previously derived theory for small banana width: when the banana width triangle b is much larger than the mode thickness triangle m , we obtain a new compact expression for the linear power transfer. When triangle m /triangle b much-lt 1, the banana orbit effect reduces the power transfer by a factor of triangle m /triangle b from that predicted by the narrow orbit theory. A comparison is made of the contribution to the TAE growth rate of energetic particles with a slowing-down distribution arising from an isotropic source, and a balance-injected beam source when the source speed is close to the Alfven speed. For the same stored energy density, the contribution from the principal resonances (|υ parallel | = υ A is substantially enhanced in the beam case compared to the isotropic case, while the contribution at the higher sidebands (|υ parallel |) = υ A /(2 ell - 1) with ell ≥ 2) is substantially reduced. 10 refs
Single-Particle Spin-Orbit Splittings in Nuclei
Kazuhiko, ANDO; Hiroharu, BANDO; Department of Physics, Kyoto University; Division of Mathematical Physics, Fukui University
1981-01-01
Single-particle spin-orbit splittings (Δ^) in ^O and ^Ca nuclei are evaluated within the framework of the effective interaction theory by employing the Reid soft-core potential and meson-exchange three-body forces (TBF). Among the two-body force contributions, the Pauli-rearrangement effect on Δ^ is studied with special care. The TBF contribution to Δ^ is found to be significant. The G-matrix, the second-order pauli-rearrangement and the TBF contribute to Δ^ by the amount of ～1/2, ～1/5 and ～1...
International Nuclear Information System (INIS)
Suparta, W; Zulkeple, S K
2014-01-01
The space environment has grown intensively harmful to spacecraft and astronauts. Galactic cosmic rays (GCRs) are one of the radiation sources that composed of high energetic particles originated from space and capable of damaging electronic systems through single event upset (SEU) process. In this paper, we analyzed GCR fluxes at different altitudes by using Space Environment Information System (SPENVIS) software and the results are compared to determine their intensities with respect to distance in the Earth's orbit. The altitudes are set at low earth orbit (400 km and 685 km), medium earth orbit (19,100 km and 20,200 km) and high earth orbit (35,793 km and 1,000,000 km). Then, within Low Earth Orbit (LEO) near the equator (NEqO), we used altitude of 685 km to compare GCRs with the intensities of solar particles and trapped particles in the radiation belt to determine the significance of GCRs in the orbit itself.
Particle orbit analysis for LHD helical axis configurations
International Nuclear Information System (INIS)
Guasp, J.; Yamazaki, K.; Motojima, O.
1993-04-01
Fast ion orbits for helical magnetic axis configurations in LHD (Large Helical Device) are analyzed and compared with the standard circular axis case. Boundaries between passing and helically trapped particle regions show clear differences: in the non-planar axis case the helically trapped region spreads, near the magnetic axis, over a much wider band across the 90deg pitch angle value and shows a very marked asymmetry. The locally trapped particle region is also wider than in the standard case. The differences in the loss cone boundaries of the two cases are rather small, however, the effects of re-entering criteria are very important in both cases. On the contrary, effects of finite coil size are not significant. (author)
Finite orbit energetic particle linear response to toroidal Alfven eigenmodes
International Nuclear Information System (INIS)
Berk, H.L.; Ye Huanchun; Breizman, B.N.
1992-01-01
The linear response of energetic particles of the TAE modes is calculated taking into account their finite orbit excursion from the flux surfaces. The general expression reproduces the previously derived theory for small banana width; when the banana width Δ b is much larger than the mode thickness Δ m , we obtain a new compact expression for the linear power transfer. When Δ m /Δ b m /Δ b from that predicted by the narrow orbit theory. A comparison is made of the contribution to the TAE growth rate of energetic particles with a slowing-down distribution arising from an isotropic source, and a balanced-injected beam source when the source speed is close to the Alfven speed. For the same stored energy density, the contribution from the principal resonances (vertical strokev parallel vertical stroke=v A ) is substantially enhanced in the beam case compared to the isotropic case, while the contribution at the higher sidebands (vertical strokev parallel vertical stroke=v A /(2l-1) with l≥2) is substantially reduced. (orig.)
Los Alamos energetic particle sensor systems at geostationary orbit
International Nuclear Information System (INIS)
Baker, D.N.; Aiello, W.; Asbridge, J.R.; Belian, R.D.; Higbie, P.R.; Klebesadel, R.W.; Laros, J.G.; Tech, E.R.
1985-01-01
The Los Alamos National Laboratory has provided energetic particle sensors for a variety of spacecraft at the geostationary orbit (36,000 km altitude). The sensor system called the Charged Particle Analyzer (CPA) consists of four separate subsystems. The LoE and HiE subsystems measure electrons in the energy ranges 30 to 300 keV and 200 to 2000 keV, respectively. The LoP and HiP subsystems measure ions in the ranges 100 to 600 keV and 0.40 to 150 MeV, respectively. A separate sensor system called the spectrometer for energetic electrons (SEE) measures very high-energy electrons (2 to 15 MeV) using advanced scintillator design. In this paper we describe the relationship of operational anomalies and spacecraft upsets to the directly measured energetic particle environments at 6.6 R/sub E/. We also compare and contrast the CPA and SEE instrument design characteristics with the next generation of Los Alamos instruments to be flown at geostationary altitudes
Role of bumpy fields on single particle orbit in near quasihelically symmetric stellarators
International Nuclear Information System (INIS)
Seol, JaeChun; Hegna, C.C.
2004-01-01
The role of symmetry breaking on single particle orbits in near helically symmetric stellarators is investigated. In particular, the effect of a symmetry-breaking bumpy term is included in the analysis of trapped particle orbits. It is found that all trapped particle drift orbits are determined by surfaces on which vertical bar B vertical bar min is constant. Trapped particle orbits reside on these surfaces regardless of pitch angle and are determined solely by the initial position and the shape of the vertical bar B vertical bar min contour. Since vertical bar B vertical bar min contours do not depend on the direction of the banana center motion, superbanana orbits do not appear
Innermost stable circular orbit of spinning particle in charged spinning black hole background
Zhang, Yu-Peng; Wei, Shao-Wen; Guo, Wen-Di; Sui, Tao-Tao; Liu, Yu-Xiao
2018-04-01
In this paper we investigate the innermost stable circular orbit (ISCO) (spin-aligned or anti-aligned orbit) for a classical spinning test particle with the pole-dipole approximation in the background of Kerr-Newman black hole in the equatorial plane. It is shown that the orbit of the spinning particle is related to the spin of the test particle. The motion of the spinning test particle will be superluminal if its spin is too large. We give an additional condition by considering the superluminal constraint for the ISCO in the black hole backgrounds. We obtain numerically the relations between the ISCO and the properties of the black holes and the test particle. It is found that the radius of the ISCO for a spinning test particle is smaller than that of a nonspinning test particle in the black hole backgrounds.
Acoustic Virtual Vortices with Tunable Orbital Angular Momentum for Trapping of Mie Particles
Marzo, Asier; Caleap, Mihai; Drinkwater, Bruce W.
2018-01-01
Acoustic vortices can transfer angular momentum and trap particles. Here, we show that particles trapped in airborne acoustic vortices orbit at high speeds, leading to dynamic instability and ejection. We demonstrate stable trapping inside acoustic vortices by generating sequences of short-pulsed vortices of equal helicity but opposite chirality. This produces a "virtual vortex" with an orbital angular momentum that can be tuned independently of the trapping force. We use this method to adjust the rotational speed of particles inside a vortex beam and, for the first time, create three-dimensional acoustics traps for particles of wavelength order (i.e., Mie particles).
DEVIATION OF STELLAR ORBITS FROM TEST PARTICLE TRAJECTORIES AROUND SGr A* DUE TO TIDES AND WINDS
International Nuclear Information System (INIS)
Psaltis, Dimitrios; Li, Gongjie; Loeb, Abraham
2013-01-01
Monitoring the orbits of stars around Sgr A* offers the possibility of detecting the precession of their orbital planes due to frame dragging, of measuring the spin and quadrupole moment of the black hole, and of testing the no-hair theorem. Here we investigate whether the deviations of stellar orbits from test-particle trajectories due to wind mass loss and tidal dissipation of the orbital energy compromise such measurements. We find that the effects of stellar winds are, in general, negligible. On the other hand, for the most eccentric orbits (e > 0.96) for which an optical interferometer, such as GRAVITY, will detect orbital plane precession due to frame dragging, the tidal dissipation of orbital energy occurs at timescales comparable to the timescale of precession due to the quadrupole moment of the black hole. As a result, this non-conservative effect is a potential source of systematic uncertainty in testing the no-hair theorem with stellar orbits
DEVIATION OF STELLAR ORBITS FROM TEST PARTICLE TRAJECTORIES AROUND SGr A* DUE TO TIDES AND WINDS
Energy Technology Data Exchange (ETDEWEB)
Psaltis, Dimitrios [Astronomy Department, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States); Li, Gongjie; Loeb, Abraham, E-mail: dpsaltis@email.arizona.edu, E-mail: gli@cfa.harvard.edu, E-mail: aloeb@cfa.harvard.edu [Institute for Theory and Computation, Harvard-Smithsonian CfA, 60 Garden Street, Cambridge, MA (United States)
2013-11-01
Monitoring the orbits of stars around Sgr A* offers the possibility of detecting the precession of their orbital planes due to frame dragging, of measuring the spin and quadrupole moment of the black hole, and of testing the no-hair theorem. Here we investigate whether the deviations of stellar orbits from test-particle trajectories due to wind mass loss and tidal dissipation of the orbital energy compromise such measurements. We find that the effects of stellar winds are, in general, negligible. On the other hand, for the most eccentric orbits (e > 0.96) for which an optical interferometer, such as GRAVITY, will detect orbital plane precession due to frame dragging, the tidal dissipation of orbital energy occurs at timescales comparable to the timescale of precession due to the quadrupole moment of the black hole. As a result, this non-conservative effect is a potential source of systematic uncertainty in testing the no-hair theorem with stellar orbits.
Yang, Hongu; Ishiguro, Masateru
2018-02-01
In this study, we numerically investigated the orbital evolution of cometary dust particles, with special consideration of the initial size–frequency distribution (SFD) and different evolutionary tracks according to the initial orbit and particle shape. We found that close encounters with planets (mostly Jupiter) are the dominating factor determining the orbital evolution of dust particles. Therefore, the lifetimes of cometary dust particles (∼250,000 yr) are shorter than the Poynting–Robertson lifetime, and only a small fraction of large cometary dust particles can be transferred into orbits with small semimajor axes. The exceptions are dust particles from 2P/Encke and, potentially, active asteroids that have little interaction with Jupiter. We also found that the effects of dust shape, mass density, and SFD were not critical in the total mass supply rate to the interplanetary dust particle (IDP) cloud complex when these quantities are confined by observations of zodiacal light brightness and SFD around the Earth’s orbit. When we incorporate a population of fluffy aggregates discovered in the Earth’s stratosphere and the coma of 67P/Churyumov–Gerasimenko within the initial ejection, the initial SFD measured at the comae of comets (67P and 81P/Wild 2) can produce the observed SFD around the Earth’s orbit. Considering the above effects, we derived the probability of mutual collisions among dust particles within the IDP cloud for the first time in a direct manner via numerical simulation and concluded that mutual collisions can mostly be ignored.
Transfer of orbital angular momentum to an optically trapped low-index particle
International Nuclear Information System (INIS)
Garces-Chavez, V.; Sibbett, W.; Dholakia, K.; Volke-Sepulveda, K.; Chavez-Cerda, S.
2002-01-01
We demonstrate the transfer of orbital angular momentum from a light beam to a trapped low-index particle. The particle is trapped in a dark annular region of a high-order Bessel beam and rotates around the beam axis due to scattering from the helical wave fronts of the light beam. A general theoretical geometrical optics model is developed that, applied to our specific situation, corroborates tweezing and transfer of orbital angular momentum to the low-index particle. Good quantitative agreement between theory and experiment for particle rotation rates is observed
Classification of particle orbits near the magnetic axis in a tokamak by using constants of motion
International Nuclear Information System (INIS)
Satake, Shinsuke; Sugama, Hideo; Okamoto, Masao; Wakatani, Masahiro
2001-01-01
A classification of particle orbits near the magnetic axis in a tokamak is presented in a space of constants of motion (COM), which is important to apply Lagrangian formulation of neoclassical transport theory to the region near the axis. Orbit types are distinguished by the number of the turning points of σsub(parallel)=υsub(parallel)/|υsub(parallel)| and σ θ =θ-bar/|θ-bar| on each orbit, where υsub(parallel) is the velocity parallel to the magnetic field, and θ-bar(≡v·∇θ) is the poloidal angular velocity. As a set of COM, (ε, μ, ) is taken, where ε is the energy of a particle, μ is the magnetic moment, and is the bounce-averaged minor radius position of a particle orbit. Compared with a familiar set of COM (υ, ξ s , r s ), where υ is the particle velocity, r s is the minor radius at which an orbit crosses the mid-plane, and ξ s =υsub(parallel)/υ evaluated at the crossing point, the set of COM (ε, μ, ) is more suitable in practice for Lagrangian formulation of neoclassical transport theory, in which the particle diffusion is described by the change of average position of particles by collisions. Near the magnetic axis, it is found that there are overlaps in regions of orbit types in the (ε, μ, ) space and that has a minimum value for a given ε. (author)
Perturbative evolution of particle orbits around Kerr black holes: time-domain calculation
Energy Technology Data Exchange (ETDEWEB)
Lopez-Aleman, Ramon [Physical Sciences Department, University of Puerto Rico-Rio Piedras, San Juan, PR 00931 (Puerto Rico); Khanna, Gaurav [Natural Science Division, Long Island University, Southampton, NY 11968 (United States); Pullin, Jorge [Department of Physics and Astronomy, Louisiana State University, 202 Nicholson Hall, Baton Rouge, LA 70803-4001 (United States)
2003-07-21
We consider the problem of the gravitational waves produced by a particle of negligible mass orbiting a Kerr black hole. We treat the Teukolsky perturbation equation in the time domain numerically as a 2 + 1 partial differential equation. We model the particle by smearing the singularities in the source term by the use of narrow Gaussian distributions. We have been able to reproduce earlier results for equatorial circular orbits that were computed using the frequency-domain formalism. The time-domain approach is however geared for a more general evolution, for instance of nearly geodesic orbits under the effects of radiation reaction.
Perturbative evolution of particle orbits around Kerr black holes: time-domain calculation
International Nuclear Information System (INIS)
Lopez-Aleman, Ramon; Khanna, Gaurav; Pullin, Jorge
2003-01-01
We consider the problem of the gravitational waves produced by a particle of negligible mass orbiting a Kerr black hole. We treat the Teukolsky perturbation equation in the time domain numerically as a 2 + 1 partial differential equation. We model the particle by smearing the singularities in the source term by the use of narrow Gaussian distributions. We have been able to reproduce earlier results for equatorial circular orbits that were computed using the frequency-domain formalism. The time-domain approach is however geared for a more general evolution, for instance of nearly geodesic orbits under the effects of radiation reaction
Some features of particle orbit behavior in LHD configurations
International Nuclear Information System (INIS)
Shishkin, A.A.; Watanabe, K.Y.; Yamazaki, K.; Motojima, O.; Grekov, D.L.; Smirnova, M.S.; Zolotukhin, A.V.
1993-03-01
Localizations of helically trapped particle losses on the last closed magnetic surface in different LHD configurations are studied. The effects of electric field, finite β and bootstrap current are taken into account. It is shown that the angular location of the helically trapped particle losses may be controlled by the change of vertical field coil currents. (author)
Chaos and nonlinear dynamics of single-particle orbits in a magnetotaillike magnetic field
Chen, J.; Palmadesso, P. J.
1986-01-01
The properties of charged-particle motion in Hamiltonian dynamics are studied in a magnetotaillike magnetic field configuration. It is shown by numerical integration of the equation of motion that the system is generally nonintegrable and that the particle motion can be classified into three distinct types of orbits: bounded integrable orbits, unbounded stochastic orbits, and unbounded transient orbits. It is also shown that different regions of the phase space exhibit qualitatively different responses to external influences. The concept of 'differential memory' in single-particle distributions is proposed. Physical implications for the dynamical properties of the magnetotail plasmas and the possible generation of non-Maxwellian features in the distribution functions are discussed.
Gravitational waveforms from a point particle orbiting a Schwarzschild black hole
International Nuclear Information System (INIS)
Martel, Karl
2004-01-01
We numerically solve the inhomogeneous Zerilli-Moncrief and Regge-Wheeler equations in the time domain. We obtain the gravitational waveforms produced by a point particle of mass μ traveling around a Schwarzschild black hole of mass M on arbitrary bound and unbound orbits. Fluxes of energy and angular momentum at infinity and the event horizon are also calculated. Results for circular orbits, selected cases of eccentric orbits, and parabolic orbits are presented. The numerical results from the time-domain code indicate that, for all three types of orbital motion, black hole absorption contributes less than 1% of the total flux, so long as the orbital radius r p (t) satisfies r p (t)>5M at all times
Relativistic equation of the orbit of a particle in a arbitrary central force field
International Nuclear Information System (INIS)
Aaron, Francisc D.
2005-01-01
The equation of the orbit of a relativistic particle moving in an arbitrary central force field is derived. Straightforward generalizations of well-known first and second order differential equations are given. It is pointed out that the relativistic equation of the orbit has the same form as in the non-relativistic case, the only changes consisting in the appearance of additional terms proportional to 1/c 2 in both potential and total energies. (author)
Xu, Guochang
2008-01-01
This is the first book of the satellite era which describes orbit theory with analytical solutions of the second order with respect to all possible disturbances. Based on such theory, the algorithms of orbits determination are completely revolutionized.
International Nuclear Information System (INIS)
Anderson, D.V.; Cohen, R.H.; Ferguson, J.R.; Johnston, B.M.; Sharp, C.B.; Willmann, P.A.
1981-01-01
The single particle orbit code, TIBRO, has been modified extensively to improve the interpolation methods used and to allow use of vector potential fields in the simulation of charged particle orbits on a 3D domain. A 3D cubic B-spline algorithm is used to generate spline coefficients used in the interpolation. Smooth and accurate field representations are obtained. When vector potential fields are used, the 3D cubic spline interpolation formula analytically generates the magnetic field used to push the particles. This field has del.BETA = 0 to computer roundoff. When magnetic induction is used the interpolation allows del.BETA does not equal 0, which can lead to significant nonphysical results. Presently the code assumes quadrupole symmetry, but this is not an essential feature of the code and could be easily removed for other applications. Many details pertaining to this code are given on microfiche accompanying this report
International Nuclear Information System (INIS)
Bruk, Yulii M; Voloshchuk, Aleksandr N
2012-01-01
The functional Pais equation for scattering phases with nonzero orbital momenta is solved in the case of low-energy particles. For short-range screened potentials, in particular, Yukawa or Thomas-Fermi potentials, the Pais equation is shown to reduce to transcendental equations. For the potentials varying ∼r - n , n > 0, simple algebraic equations are obtained for determining the phases δ l , l≠0. Possible applications of the Pais approximation to the problem of finding resonance regimes in the scattering of low-energy particles with nonzero orbital momenta are discussed. (methodological notes)
A new seniority scheme for non-degenerate single particle orbits
International Nuclear Information System (INIS)
Otsuka, T.; Arima, A.
1978-01-01
A new method is proposed in the treatment of the seniority scheme. The method enables one to evaluate analytically the contribution from J = 0 Cooper pairs in non-degenerate single-particle orbits to many-body matrix elements. It includes the SU(2) quasi-spin and the BCS approximation as two extreme limits. The effect of particle number conservation is properly taken into account. (Auth.)
Yourshaw, Matthew Stephen
2017-01-01
Orbital is a virtual reality gaming experience designed to explore the use of traditional narrative structure to enhance immersion in virtual reality. The story structure of Orbital was developed based on the developmental steps of 'The Hero's Journey,' a narrative pattern identified by Joseph Campbell. Using this standard narrative pattern, Orbital is capable of immersing the player quickly and completely for the entirety of play time. MFA
Orbital diamagnetism of a charged Brownian particle undergoing birth-death process
International Nuclear Information System (INIS)
Jayannawar, A.M.; Kumar, N.
1980-06-01
We consider the magnetic response of a charged Brownian particle undergoing a stochastic birth-death process. The latter simulates the electron-hole pair production and recombination in semiconductors. We obtain non-zero, orbital diamagnetism which can be large without violating the Van Leeuwen theorem. (author)
Orbital Evolution of Dust Particles in the Sublimation Zone near the Sun
Shestakova, L. I.; Demchenko, B. I.
2018-03-01
We have performed the calculations of the orbital evolution of dust particles from volcanic glass ( p-obsidian), basalt, astrosilicate, olivine, and pyroxene in the sublimation zone near the Sun. The sublimation (evaporation) rate is determined by the temperature of dust particles depending on their radius, material, and distance to the Sun. All practically important parameters that characterize the interaction of spherical dust particles with the radiation are calculated using the Mie theory. The influence of radiation and solar wind pressure, as well as the Poynting-Robertson drag force effects on the dust dynamics, are also taken into account. According to the observations (Shestakova and Demchenko, 2016), the boundary of the dust-free zone is 7.0-7.6 solar radii for standard particles of the zodiacal cloud and 9.1-9.2 solar radii for cometary particles. The closest agreement is obtained for basalt particles and certain kinds of olivine, pyroxene, and volcanic glass.
International Nuclear Information System (INIS)
Lanzanò, L; Gratton, E
2014-01-01
Single Particle Tracking (SPT) is a technique used to locate fluorescent particles with nanometer precision. In the orbital tracking method the position of a particle is obtained analyzing the distribution of intensity along a circular orbit scanned around the particle. In combination with an active feedback this method allows tracking of particles in 2D and 3D with millisecond temporal resolution. Here we describe a SPT setup based on a feedback approach implemented with minimal modification of a commercially available confocal laser scanning microscope, the Zeiss LSM 510, in combination with an external piezoelectric stage scanner. The commercial microscope offers the advantage of a user-friendly software interface and pre-calibrated hardware components. The use of an external piezo-scanner allows the addition of feedback into the system but also represents a limitation in terms of its mechanical response. We describe in detail this implementation of the orbital tracking method and discuss advantages and limitations. As an example of application to live cell experiments we perform the 3D tracking of acidic vesicles in live polarized epithelial cells. (paper)
Neoclassical alpha-particle losses in tokamaks allowing for large orbit widths
International Nuclear Information System (INIS)
Cox, M.; O'Brien, M.R.; Zaitsev, F.S.
1994-01-01
Alpha-particle physics is of particular importance now that research into controlled fusion has reached thermonuclear parameters and D-T fuel has been used in JET and TFTR. Here we address the important topic of α-particle transport: if transport is too low helium ash accumulates quenching the burn; if it is too high heating of the plasma by fast α-particles is insufficient to maintain the burn. We give results from simulations of α-particle distributions (f α ) which self-consistently treat α-particle birth, collisional slowing down and neoclassical radial transport. The (steady-state) f α is calculated by the FPP code as a function of speed (v), pitch-angle (θ) and flux surface radius (r). This code is based on a 3D Fokker-Planck theory of 'banana regime' neoclassical effects in tokamaks which can treat large deviations of fast ion orbits from flux surfaces and non-Maxwellian distributions. The code reproduces standard neoclassical results for Maxwellian distributions in the large aspect ratio (ε) and small orbit width (Δ) limits (e.g. radial fluxes, conductivities and bootstrap currents), but can also be used for small ε and large Δ which are difficult to treat analytically. The code is particularly useful for α-particle studies as (a) the experimental evidence is that fast ion transport is usually consistent with neoclassical theory, unlike electron or thermal ion transport, and (b) trapped fast ion orbits can deviate greatly from flux surfaces. An alternative to this Fokker-Planck treatment is Monte Carlo modelling. However, representation of the detailed structure of f α (θ,v,r) would require very large number of particles, and hence be very slow. Calculations have been made for parameters typical of TFTR, JET, SSTR (an 'advanced tokamak' reactor) and STR (a tight aspect ratio or 'spherical' tokamak reactor, though only the JET results are discussed in detail. (author) 4 refs., 4 figs
General classification of charged test particle circular orbits in Reissner-Nordstroem spacetime
Energy Technology Data Exchange (ETDEWEB)
Pugliese, D. [Silesian University in Opava, Institute of Physics, Faculty of Philosophy and Science, Opava (Czech Republic); Quevedo, H. [Universita di Roma ' ' La Sapienza' ' , Dipartimento di Fisica, ICRA, Rome (Italy); Icranet-Pescara, Pescara (Italy); Universidad Nacional Autonoma de Mexico, Instituto de Ciencias Nucleares, Mexico, DF (Mexico); Kazakh National University, Department of Theoretical and Nuclear Physics, Almaty (Kazakhstan); Ruffini, R. [Universita di Roma ' ' La Sapienza' ' , Dipartimento di Fisica, ICRA, Rome (Italy); Icranet-Pescara, Pescara (Italy)
2017-04-15
We investigate charged particles' circular motion in the gravitational field of a charged mass distribution described by the Reissner-Nordstroem spacetime. We introduce a set of independent parameters completely characterizing the different spatial regions in which circular motion is allowed. We provide a most complete classification of circular orbits for different sets of particle and source charge-to-mass ratios. We study both black holes and naked singularities and show that the behavior of charged particles depend drastically on the type of source. Our analysis shows in an alternative manner that the behavior of circular orbits can in principle be used to distinguish between black holes and naked singularities. From this analysis, special limiting values for the dimensionless charge of black hole and naked singularity emerge, namely, Q/M = 1/2, Q/M = √(13)/5 and Q/M = √(2/3) for the black hole case and Q/M = 1, Q/M = 5/(2√(6)), Q/M = 3√(6)/7, and finally Q/M = √(9/8) for the naked singularity case. Similarly and surprisingly, analogous limits emerge for the orbiting particles charge-to-mass ratio ε, for positive charges ε = 1, ε = 2 and ε = M/Q. These limits play an important role in the study of the coupled electromagnetic and gravitational interactions, and the investigation of the role of the charge in the gravitational collapse of compact objects. (orig.)
International Nuclear Information System (INIS)
Zaslavskii, Oleg B
2012-01-01
We study the effect of collisions of ultrahigh energy particles near the black hole horizon (BSW effect) for two scenarios: when one of the particles either (i) moves on a circular orbit or (ii) plunges from it toward the horizon. It is shown that such circular near-horizon orbits can exist for near-extremal black holes only. This includes the innermost stable orbit (ISCO), marginally bound orbit (MBO) and photon one (PhO). We consider generic ‘dirty’ rotating black holes not specifying the metric and show that the energy in the center-of-mass frame has the universal scaling dependence on the surface gravity κ. Namely, E c.m. ∼ κ −n where for the ISCO, n= 1/3 in case (i) or n= 1/2 in case (ii). For the MBO and PhCO, n= 1/2 in both scenarios that agrees with recent calculations of Harada and Kimura for the Kerr metric. We also generalize the Grib and Pavlov observations made for the Kerr metric. The magnitude of the BSW effect on the location of collision has a somewhat paradoxical character: it decreases when approaching the horizon. (paper)
Zaslavskii, Oleg B.
2012-10-01
We study the effect of collisions of ultrahigh energy particles near the black hole horizon (BSW effect) for two scenarios: when one of the particles either (i) moves on a circular orbit or (ii) plunges from it toward the horizon. It is shown that such circular near-horizon orbits can exist for near-extremal black holes only. This includes the innermost stable orbit (ISCO), marginally bound orbit (MBO) and photon one (PhO). We consider generic ‘dirty’ rotating black holes not specifying the metric and show that the energy in the center-of-mass frame has the universal scaling dependence on the surface gravity κ. Namely, Ec.m. ˜ κ-n where for the ISCO, n=\\frac{1}{3} in case (i) or n=\\frac{1}{2} in case (ii). For the MBO and PhCO, n=\\frac{1}{2} in both scenarios that agrees with recent calculations of Harada and Kimura for the Kerr metric. We also generalize the Grib and Pavlov observations made for the Kerr metric. The magnitude of the BSW effect on the location of collision has a somewhat paradoxical character: it decreases when approaching the horizon.
Local time asymmetry of Pc 4--5 pulsations and associated particle modulations at synchronous orbit
International Nuclear Information System (INIS)
Kokubun, S.; Erickson, K.N.; Fritz, T.A.; McPherron, R.L.
1989-01-01
Magnetic field and particle flux observations on board ATS 6 at synchronous altitude are used to examine the dawn-dusk asymmetry of characteristics of Pc 4--5 waves and associated particle flux modulation. Most waves at synchronous orbit having ground correlations are polarized in the azimuthal direction (A class) and are usually detected in the dawn sector. Waves with a radially oriented polarization ellipse (R-class) are almost never observed near the subsatellite point on the ground, except for the regular pulsations known as giant pulsation Pg, observed in the early morning. R class Pc 4 waves occur at all local times and have an occurrence peak in the afternoon
Electromagnetic spin–orbit interaction and giant spin-Hall effect in dielectric particle clusters
Energy Technology Data Exchange (ETDEWEB)
Liu, Yineng [Department of Physics, Beijing Normal University, Beijing 100875 (China); Zhang, Xiangdong, E-mail: zhangxd@bit.edu.cn [School of Physics and Beijing Key Laboratory of Nanophotonics and Ultrafine Optoelectronic Systems, Beijing Institute of Technology, 100081, Beijing (China)
2013-12-09
We report a phenomenon that electromagnetic spin–orbit interactions can be tailored by dielectric nanoparticles, and self-similar giant spin-Hall effect has been observed in the dielectric particle cluster. The near-field phase singularities and phase vorticity in the longitudinal component of scattered field can also be controlled by such a dielectric structure. The origin of phenomena is believed to be due to the collective resonance excitation in the dielectric particle cluster. It is expected to find applications in optics information processing and designing new nanophotonic devices.
Spin flip due to the spin–orbit interaction of colliding slow charged particles
International Nuclear Information System (INIS)
Sasorov, P. V.; Fomin, I. V.
2017-01-01
The scattering amplitudes of point charged particles is calculated analytically taking into account the spin–orbit interaction. We have considered two cases typical of a hydrogen-like plasma: scattering of an electron by a heavy ion and scattering of an electron by a free electron. The results have been obtained taking into account the ranges of low collision energies smaller than α"2m_ec"2, where α is the fine structure constant.
Representation of Probability Density Functions from Orbit Determination using the Particle Filter
Mashiku, Alinda K.; Garrison, James; Carpenter, J. Russell
2012-01-01
Statistical orbit determination enables us to obtain estimates of the state and the statistical information of its region of uncertainty. In order to obtain an accurate representation of the probability density function (PDF) that incorporates higher order statistical information, we propose the use of nonlinear estimation methods such as the Particle Filter. The Particle Filter (PF) is capable of providing a PDF representation of the state estimates whose accuracy is dependent on the number of particles or samples used. For this method to be applicable to real case scenarios, we need a way of accurately representing the PDF in a compressed manner with little information loss. Hence we propose using the Independent Component Analysis (ICA) as a non-Gaussian dimensional reduction method that is capable of maintaining higher order statistical information obtained using the PF. Methods such as the Principal Component Analysis (PCA) are based on utilizing up to second order statistics, hence will not suffice in maintaining maximum information content. Both the PCA and the ICA are applied to two scenarios that involve a highly eccentric orbit with a lower apriori uncertainty covariance and a less eccentric orbit with a higher a priori uncertainty covariance, to illustrate the capability of the ICA in relation to the PCA.
Many-body calculations with deuteron based single-particle bases and their associated natural orbits
Puddu, G.
2018-06-01
We use the recently introduced single-particle states obtained from localized deuteron wave-functions as a basis for nuclear many-body calculations. We show that energies can be substantially lowered if the natural orbits (NOs) obtained from this basis are used. We use this modified basis for {}10{{B}}, {}16{{O}} and {}24{{Mg}} employing the bare NNLOopt nucleon–nucleon interaction. The lowering of the energies increases with the mass. Although in principle NOs require a full scale preliminary many-body calculation, we found that an approximate preliminary many-body calculation, with a marginal increase in the computational cost, is sufficient. The use of natural orbits based on an harmonic oscillator basis leads to a much smaller lowering of the energies for a comparable computational cost.
Measurement of particle directions in low earth orbit with a Timepix
International Nuclear Information System (INIS)
Gohl, St.; Bergmann, B.; Granja, C.; Pichotka, M.; Polansky, S.; Pospisil, S.; Owens, A.
2016-01-01
In Low Earth Orbit (LEO) in space electronic equipment aboard satellites and space crews are exposed to high ionizing radiation levels. To reduce radiation damage and the exposure of astronauts, to improve shielding and to assess dose levels, it is valuable to know the composition of the radiation fields and particle directions. The presented measurements are carried out with the Space Application of Timepix Radiation Monitor (SATRAM). There, a Timepix detector (300 μm thick silicon sensor, pixel pitch 55 μm, 256 × 256 pixels) is attached to the Proba-V, an earth observing satellite of the European Space Agency (ESA). The Timepix detector's capability was used to determine the directions of energetic charged particles and their corresponding stopping powers. Data are continuously taken at an altitude of 820 km on a sun-synchronous orbit. The particles pitch angles with respect to the sensor layer were measured and converted to an Earth Centred Earth Fixed (ECEF) coordinate system. Deviations from an isotropic field are extracted by normalization of the observed angular distributions by a Geant4 Monte Carlo simulation —taking the systematics of the reconstruction algorithm and the pixelation into account.
AMS_02 Particle Physics Detector Technologies Orbiting the Earth (2/2)
CERN. Geneva
2012-01-01
AMS-02 has taken the high performance technologies used in particle physics and implemented them for use in low Earth orbit. Safety aspects for the Space Shuttle flight, that carried AMS_02 to the International Space Station, Space environment and inaccessibility during the life of AMS_02 are some of the aspects which have driven the design of the experiment. The technical challenges to build such a detector have been surmounted through the close collaboration amongst the AMS scientists and industries around the world. Their efforts have resulted in the development of new technologies and higher standards of precision.
AMS_02 Particle Physics Detector Technologies Orbiting the Earth (1/2)
CERN. Geneva
2012-01-01
AMS-02 has taken the high performance technologies used in particle physics and implemented them for use in low Earth orbit. Safety aspects for the Space Shuttle flight, that carried AMS_02 to the International Space Station, Space environment and inaccessibility during the life of AMS_02 are some of the aspects which have driven the design of the experiment. The technical challenges to build such a detector have been surmounted through the close collaboration amongst the AMS scientists and industries around the world. Their efforts have resulted in the development of new technologies and higher standards of precision.
Spectral Gaps of Spin-orbit Coupled Particles in Deformed Traps
DEFF Research Database (Denmark)
V. Marchukov, O.; G. Volosniev, A.; V. Fedorov, D.
2013-01-01
the spectrum. The effect of a Zeeman term is also considered. Our results demonstrate that variable spectral gaps occur as a function of strength of the Rashba interaction and deformation of the harmonic trapping potential. The single-particle density of states and the critical strength for superfluidity vary...... tremendously with the interaction parameter. The strong variations with Rashba coupling and deformation implies that the few- and many-body physics of spin-orbit coupled systems can be manipulated by variation of these parameters....
Nuclear propulsion systems for orbit transfer based on the particle bed reactor
International Nuclear Information System (INIS)
Powell, J.R.; Ludewig, H.; Horn, F.L.
1987-01-01
The technology of nuclear direct propulsion orbit transfer systems based on the Particle Bed Reactor (PBR) is described. A 200 megawatt illustrative design is presented for LEO to GEO and other high ΔV missions. The PBR-NOTV can be used in a one-way mode with the shuttle or an expendable launch vehicle, e.g., the Titan 34D7, or as a two-way reusable space tug. In the one-way mode, payload capacity is almost three times greater than that of chemical OTV's. PBR technology status is described and development needs outlined
Exploring one-particle orbitals in large many-body localized systems
Villalonga, Benjamin; Yu, Xiongjie; Luitz, David J.; Clark, Bryan K.
2018-03-01
Strong disorder in interacting quantum systems can give rise to the phenomenon of many-body localization (MBL), which defies thermalization due to the formation of an extensive number of quasilocal integrals of motion. The one-particle operator content of these integrals of motion is related to the one-particle orbitals (OPOs) of the one-particle density matrix and shows a strong signature across the MBL transition as recently pointed out by Bera et al. [Phys. Rev. Lett. 115, 046603 (2015), 10.1103/PhysRevLett.115.046603; Ann. Phys. 529, 1600356 (2017), 10.1002/andp.201600356]. We study the properties of the OPOs of many-body eigenstates of an MBL system in one dimension. Using shift-and-invert MPS, a matrix product state method to target highly excited many-body eigenstates introduced previously [Phys. Rev. Lett. 118, 017201 (2017), 10.1103/PhysRevLett.118.017201], we are able to obtain accurate results for large systems of sizes up to L =64 . We find that the OPOs drawn from eigenstates at different energy densities have high overlap and their occupations are correlated with the energy of the eigenstates. Moreover, the standard deviation of the inverse participation ratio of these orbitals is maximal at the nose of the mobility edge. Also, the OPOs decay exponentially in real space, with a correlation length that increases at low disorder. In addition, we find that the probability distribution of the strength of the large-range coupling constants of the number operators generated by the OPOs approach a log-uniform distribution at strong disorder.
Rubincam, David P.
2013-01-01
The thermal expansion and contraction of ring particles orbiting a planet or asteroid can cause secular orbit evolution. This effect, called here the thermal expansion effect, depends on ring particles entering and exiting the shadow of the body they orbit. A particle cools off in the shadow and heats up again in the sunshine, suffering thermal contraction and expansion. The changing cross-section it presents to solar radiation pressure plus time lags due to thermal inertia lead to a net along-track force. The effect causes outward drift for rocky particles. For the equatorial orbits considered here, the thermal expansion effect is larger than Poynting-Robertson drag in the inner solar system for particles in the size range approx. 0.001 - 0.02 m. This leads to a net increase in the semimajor axis from the two opposing effects at rates ranging from approx. 0.1 R per million years for Mars to approx. 1 R per million years for Mercury, for distances approx. 2R from the body, where R is the body's radius. Asteroid 243 Ida has approx. 10 R per million years, while a hypothetical Near-Earth Asteroid (NEA) can have faster rates of approx. 0.5 R per thousand years, due chiefly to its small radius compared to the planets. The thermal expansion effect weakens greatly at Jupiter and is overwhelmed by Poynting-Robertson for icy particles orbiting Saturn. Meteoroids in eccentric orbits about the Sun also suffer the thermal expansion effect, but with only approx. 0.0003e2 AU change in semimajor axis over a million years for a 2 m meteoroid orbiting between Mercury and Earth.
Response of energetic particles to local magnetic dipolarization inside geosynchronous orbit
Motoba, T.; Ohtani, S.; Gkioulidou, M.; Takahashi, K.
2017-12-01
Magnetic field dipolarization and energetic particle injections are the most distinct phenomena observed in the inner magnetosphere during the substorm expansion phase. Compared to a wealth of knowledge about the phenomenology of magnetic dipolarizations and particle injections at/outside geosynchronous orbit (GEO), our understanding of them inside GEO remains incomplete because of a very limited number of previous studies. In the present study, we statistically examine the response of 1-1000 keV energetic particles to local magnetic dipolarization by performing a superposed epoch analysis of energetic particle fluxes with the zero epoch defined as the dipolarization onset times. Based on data from the Van Allen Probes tail seasons in 2012-2016, we identified a total of 97 magnetic dipolarization events which occurred closer to the magnetic equator (i.e., BH, which is antiparallel to the Earth's dipole axis, is the dominant component of the local magnetic field at least for 5 min before the onset). For major ion species (hydrogen, helium, and oxygen ions), the relative flux intensity to the pre-onset level increases at > 50 keV and decreases at inverse energy dispersion. For dipolarizations with strong impulsive westward electric fields, the relative electron flux intensity increases up to 5-10 times, in particular most significant at several tens of keV. This result suggests that the impulsive electric field acts as an efficient factor in the rapid energization of the tens-of-keV electrons. We also discuss how the response of energetic particles to dipolarization depends on MLT, radial distance, and pitch angle.
International Nuclear Information System (INIS)
Yang Huatong
2007-01-01
Some exact identities connecting one- and two-particle Green's functions in the presence of spin-orbit coupling have been derived. These identities are similar to the Ward identity in usual quantum transport theory of electrons. A satisfying approximate calculation of the spin transport in spin-orbit coupling system should also preserve these identities, just as the Ward identities should be remained in the usual electronic transport theory
SimTrack: A compact c++ code for particle orbit and spin tracking in accelerators
Energy Technology Data Exchange (ETDEWEB)
Luo, Yun
2015-11-21
SimTrack is a compact c++ code of 6-d symplectic element-by-element particle tracking in accelerators originally designed for head-on beam–beam compensation simulation studies in the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory. It provides a 6-d symplectic orbit tracking with the 4th order symplectic integration for magnet elements and the 6-d symplectic synchro-beam map for beam–beam interaction. Since its inception in 2009, SimTrack has been intensively used for dynamic aperture calculations with beam–beam interaction for RHIC. Recently, proton spin tracking and electron energy loss due to synchrotron radiation were added. In this paper, I will present the code architecture, physics models, and some selected examples of its applications to RHIC and a future electron-ion collider design eRHIC.
SimTrack: A compact c++ library for particle orbit and spin tracking in accelerators
Energy Technology Data Exchange (ETDEWEB)
Luo, Yun [Brookhaven National Laboratory (BNL), Upton, NY (United States)
2015-06-24
SimTrack is a compact c++ library of 6-d symplectic element-by-element particle tracking in accelerators originally designed for head-on beam-beam compensation simulation studies in the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory. It provides a 6-d symplectic orbit tracking with the 4th order symplectic integration for magnet elements and the 6-d symplectic synchro-beam map for beam-beam interaction. Since its inception in 2009, SimTrack has been intensively used for dynamic aperture calculations with beam-beam interaction for RHIC. Recently, proton spin tracking and electron energy loss due to synchrotron radiation were added. In this article, I will present the code architecture, physics models, and some selected examples of its applications to RHIC and a future electron-ion collider design eRHIC.
Particle orbits and non-ideal MHD stability of Z-pinches
International Nuclear Information System (INIS)
Faghihi, M.
1987-01-01
Particle orbits in a linear EXTRAP vacuum magnetic field configuration are computed. The results indicate that, with an applied electric field along the axis, the particles starting near the magnetic stagnation line would gain substantial energy in the 'free fall', and are the most efficient ones to participate in the ionization process. The acquired energy depends on the electric field strength; the required value of the field is determined. The influence of the pressure anisotropy on the small wavelength internal kink (m=1) mode instability in a Z-pinch, using a generalization of Freidbergs perpendicular MHD model, is investigated. It is found that the stability criterion can not be fulfilled without violation of the fire hose stability condition. This investigation is also performed using the double-adiabatic theory. A finite Larmor radius treatment of the small wavelength kink instabilities for a Z-pinch geometry is presented. It is shown that, when the gyroviscosity is included in the perpendicular MHD model, exponentially growing Alfven waves are predicted even in a homogeneous static equilibrium with isotropic plasma pressure. The Hall effect in the incompressible Hall fluid model is considered. It is found that the Hall parameter reduces the growth rates of the kink modes, but it does not yield complete stabilization (author)
Particle orbits and non-ideal MHD stability of Z-pinches
Energy Technology Data Exchange (ETDEWEB)
Faghihi, M.
1987-01-01
Particle orbits in a linear EXTRAP vacuum magnetic field configuration are computed. The results indicate that, with an applied electric field along the axis, the particles starting near the magnetic stagnation line would gain substantial energy in the 'free fall', and are the most efficient ones to participate in the ionization process. The acquired energy depends on the electric field strength; the required value of the field is determined. The influence of the pressure anisotropy on the small wavelength internal kink (m=1) mode instability in a Z-pinch, using a generalization of Freidbergs perpendicular MHD model, is investigated. It is found that the stability criterion can not be fulfilled without violation of the fire hose stability condition. This investigation is also performed using the double-adiabatic theory. A finite Larmor radius treatment of the small wavelength kink instabilities for a Z-pinch geometry is presented. It is shown that, when the gyroviscosity is included in the perpendicular MHD model, exponentially growing Alfven waves are predicted even in a homogeneous static equilibrium with isotropic plasma pressure. The Hall effect in the incompressible Hall fluid model is considered. It is found that the Hall parameter reduces the growth rates of the kink modes, but it does not yield complete stabilization
International Nuclear Information System (INIS)
Nymmik, R.A.
1999-01-01
A wide range of the galactic cosmic ray and SEP event flux simulation problems for the near-Earth satellite and manned spacecraft orbits and for the interplanetary mission trajectories are discussed. The models of the galactic cosmic ray and SEP events in the Earth orbit beyond the Earth's magnetosphere are used as a basis. The particle fluxes in the near-Earth orbits should be calculated using the transmission functions. To calculate the functions, the dependences of the cutoff rigidities on the magnetic disturbance level and on magnetic local time have to be known. In the case of space flights towards the Sun and to the boundary of the solar system, particular attention is paid to the changes in the SEP event occurrence frequency and size. The particle flux gradients are applied in this case to galactic cosmic ray fluxes
Low-voltage Power Supply Subsystem for a Sub-Orbital Particle Physic Instrument
Directory of Open Access Journals (Sweden)
Hector Hugo Silva Lopez
2014-01-01
Full Text Available The Japanese Experiment Module–Extreme Universe Space Observatory (JEM-EUSO is a wide-field (+/-~30°of aperture 2.5m refractor telescope to be installed in the International Space Station (ISS. The instrument looks downward from its orbit, into Earthâ€™s atmosphere, with the main objective of observing ultra-violet (UV fluorescence light generated by Ultra-High Energy Cosmic Rays (UHECR extensive air showers (EAS. It is a frontier particle-physics experiment, the first of its kind. The validation of the technical readiness level of such a complex and unique instrument requires prototypes at several levels of integration. At the highest level, the EUSO-Balloon instrument has been conceived, through French space agency (CNES. At a smaller scale and in suborbital flight, EUSO-Balloon integrates all the sub-systems of the full space JEM-EUSO telescope, allowing end-to-end testing of hardware and interfaces, and to probing the global detection chain and strategy, while improving at the same time our knowledge of atmospheric and terrestrial UV background. EUSO-Balloon will be flown by CNES for the first time from Timmins, Canada; on spring 2014.This article presents the low-voltage power supply (LVPS subsystem development for the EUSO-Balloon instrument. This LVPS is the fully operational prototype for the space instrument JEM-EUSO. Besides design and construction, all performance tests and integration results with the other involved subsystems are shown.
Los Alamos geostationary orbit synoptic data set: a compilation of energetic particle data
International Nuclear Information System (INIS)
Baker, D.N.; Higbie, P.R.; Belian, R.D.; Aiello, W.P.; Hones, E.W. Jr.; Tech, E.R.; Halbig, M.F.; Payne, J.B.; Robinson, R.; Kedge, S.
1981-08-01
Energetic electron (30 to 2000 keV) and proton (145 keV to 150 MeV) measurements made by Los Alamos National Laboratory sensors at geostationary orbit 6.6 R/sub E/ are summarized. The data are plotted in terms of daily average spectra, 3-h local time averages, and in a variety of statistical formats. The data summarize conditions from mid-1976 through 1978 (S/C 1976-059) and from early 1977 through 1978 (S/C 1977-007). The compilations correspond to measurements at 35 0 W, 70 0 W, and 135 0 W geographic longitude and, thus, are indicative of conditions at 9 0 , 11 0 , and 4.8 0 geomagnetic latitude, respectively. Most of this report is comprised of data plots that are organized according to Carrington solar rotations so that the data can be easily compared to solar rotation-dependent interplanetary data. As shown in prior studies, variations in solar wind conditions modulate particle intensity within the terrestrial magnetosphere. The effects of these variations are demonstrated and discussed. Potential uses of the Synoptic Data Set by the scientific and applications-oriented communities are also discussed
Friedlander, A. L.; Wells, W. C.
1980-01-01
A study of long term risks is presented that treats an additional pathway that could result in earth reentry, namely, small radioactive particles released in solar orbit due to payload fragmentation by accidental explosion or meteoroid impact. A characterization of such an event and of the initial mass size distribution of particles is given for two extremes of waste form strength. Attention is given to numerical results showing the mass-time distribution of material and the fraction of initial mass intercepted by earth. It is concluded that it appears that program planners need not be to concerned about the risks of this particular failure mechanism and return pathway.
International Nuclear Information System (INIS)
Sun, Wenbo; Hu, Yongxiang; Weimer, Carl; Ayers, Kirk; Baize, Rosemary R.; Lee, Tsengdar
2017-01-01
Electromagnetic (EM) beams with orbital angular momentum (OAM) may have great potential applications in communication technology and in remote sensing of the Earth-atmosphere system and outer planets. Study of their interaction with optical lenses and dielectric or metallic objects, or scattering of them by particles in the Earth-atmosphere system, is a necessary step to explore the advantage of the OAM EM beams. In this study, the 3-dimensional (3D) scattered-field (SF) finite-difference time domain (FDTD) technique with the convolutional perfectly matched layer (CPML) absorbing boundary conditions (ABC) is applied to calculate the scattering of the purely azimuthal (the radial mode number is assumed to be zero) Laguerre–Gaussian (LG) beams with the OAM by dielectric particles. We found that for OAM beam's interaction with dielectric particles, the forward-scattering peak in the conventional phase function (P11) disappears, and light scattering peak occurs at a scattering angle of ~15° to 45°. The disappearance of forward-scattering peak means that, in laser communications most of the particle-scattered noise cannot enter the receiver, thus the received light is optimally the original OAM-encoded signal. This feature of the OAM beam also implies that in lidar remote sensing of the atmospheric particulates, most of the multiple-scattering energy will be off lidar sensors, and this may result in an accurate profiling of particle layers in the atmosphere or in the oceans by lidar, or even in the ground when a ground penetration radar (GPR) with the OAM is applied. This far-field characteristics of the scattered OAM light also imply that the optical theorem, which is derived from plane-parallel wave scattering case and relates the forward scattering amplitude to the total cross section of the scatterer, is invalid for the scattering of OAM beams by dielectric particles. - Highlights: • Scattering of orbital angular momentum (OAM) laser beam by dielectric
Semkova, Jordanka; Koleva, Rositza; Benghin, Victor; Dachev, Tsvetan; Matviichuk, Yuri; Tomov, Borislav; Krastev, Krasimir; Maltchev, Stephan; Dimitrov, Plamen; Mitrofanov, Igor; Malahov, Alexey; Golovin, Dmitry; Mokrousov, Maxim; Sanin, Anton; Litvak, Maxim; Kozyrev, Andrey; Tretyakov, Vladislav; Nikiforov, Sergey; Vostrukhin, Andrey; Fedosov, Fedor; Grebennikova, Natalia; Zelenyi, Lev; Shurshakov, Vyacheslav; Drobishev, Sergey
2018-03-01
ExoMars is a joint ESA-Rosscosmos program for investigating Mars. Two missions are foreseen within this program: one consisting of the Trace Gas Orbiter (TGO), that carries scientific instruments for the detection of trace gases in the Martian atmosphere and for the location of their source regions, plus an Entry, Descent and landing demonstrator Module (EDM), launched on March 14, 2016; and the other, featuring a rover and a surface platform, with a launch date of 2020. On October 19, 2016 TGO was inserted into high elliptic Mars' orbit. The dosimetric telescope Liulin-MO for measuring the radiation environment onboard the ExoMars 2016 TGO is a module of the Fine Resolution Epithermal Neutron Detector (FREND). Here we present first results from measurements of the charged particle fluxes, dose rates, Linear Energy Transfer (LET) spectra and estimation of dose equivalent rates in the interplanetary space during the cruise of TGO to Mars and first results from dosimetric measurements in high elliptic Mars' orbit. A comparison is made with the dose rates obtained by RAD instrument onboard Mars Science Laboratory during the cruise to Mars in 2011-2012 and with the Galactic Cosmic Rays (GCR) count rates provided by other particle detectors currently in space. The average measured dose rate in Si from GCR during the transit to Mars for the period April 22-September 15, 2016 is 372 ± 37 μGy d-1 and 390 ± 39 μGy d-1 in two perpendicular directions. The dose equivalent rate from GCR for the same time period is about 2 ± 0.3 mSv d-1. This is in good agreement with RAD results for radiation dose rate in Si from GCR in the interplanetary space, taking into account the different solar activity during the measurements of both instruments. About 10% increase of the dose rate, and 15% increase of the dose equivalent rate for 10.5 months flight is observed. It is due to the increase of Liulin-MO particle fluxes for that period and corresponds to the overall GCR intensity
Particle-in-Cell Simulation Study on the Floating Potential of Spacecraft in the Low Earth Orbit
International Nuclear Information System (INIS)
Tang Daotan; Yang Shengsheng; Zheng Kuohai; Qin Xiaogang; Li Detian; Liu Qing; Zhao Chengxuan; Du Shanshan
2015-01-01
In order to further understand the characteristics of the floating potential of low earth orbit spacecraft, the effects of the electron current collection area, background electron temperature, photocurrent emission, spacecraft wake, and the shape of spacecraft on spacecraft floating potential were studied here by particle-in-cell simulation in the low earth orbit. The simulation results show that the electron current collection area and background electron temperature impact on the floating potential by changing the electron current collection of spacecraft. By increasing the electron current collection area or background electron temperature, the spacecraft will float at a lower electric potential with respect to the surrounding plasma. However, the spacecraft wake affects the floating potential by increasing the ion current collected by spacecraft. The emission of the photocurrent from the spacecraft surface, which compensates for the electrons collected from background plasma, causes the floating potential to increase. The shape of the spacecraft is also an important factor influencing the floating potential. (paper)
International Nuclear Information System (INIS)
Malloy, J.; Potekhen, D.
1989-01-01
This paper examines the use of a particle bed reactor nuclear engine for direct thrust in a spacecraft based on the NASA/TRW orbital maneuvering vehicle (OMV). It presents the conceptual design of a 500 lb thrust engine that matches critical design features of the existing OMV bi-propellant propulsion system. This application contrasts with the usual tendency to consider a nuclear heat source either for high thrust direct propulsion or as a power source for electric propulsion. A nuclear propulsion module adapted to the OMV could potentially accomplish several Department of Defense missions, such as multiple round trips from a space-based support platform at 280 NM to service a constellation of satellites orbiting at 1800 NM
Effects of the radial electric field resonances on the particle orbits and loss cones in TJ-II
International Nuclear Information System (INIS)
Guasp, J.; Liniers, M.
1997-07-01
The effects of the radial electric field resonances on the trapping and confinement of low and intermediate energy ions (0.1-1 keV) for the Reference configuration of TJ-II have been analysed. In TJ-II these resonances appear for electric potentials that grow with pitch and with the square root of the initial kinetic energy and are placed inside strips whose width increases with the initial radius and with the absolute value of initial pitch. The 0-Resonance is the most important one for particle trapping, it appears for high electric potential (between 1000 and 3000 V for 0.5 keV ions) with the same sign than pitch, inside very wide strips (several thousands of V). Along these band periphery, for potential intensities below the central resonant values, there exists a very strong increase of particle trapping. Instead, around the resonance center, the trapping is inhibited and a very strong increase of the passing particle population appears. This increase is higher for the torus external side (Theta approximately 0 degree centigree) and for small initial radius. For peripherical particles wide loss strips appear along the border of the resonant band corresponding to more positive potential. The 2-Resonance has small effect on trapping but affects strongly to the of peripherical passing particles. It appears for moderate electric potential (between 400 and 1000 V for 0.5 keV ions) with sign opposite than pitch and inside narrow bands than the 0-Resonance. In this case a loss of peripherical passing particles appears, placed also along the more positive potential band side. The other Resonances (except the -4) have much less effect on particle trapping and confinement. All these phenomena have been explained by the action of magnetic barriers and different mechanisms for particle orbit modification. (Author) 8 refs
International Nuclear Information System (INIS)
Chin Yongho.
1986-09-01
In order to explain the large discrepancy between the measured transverse coherent tune shifts and analytical ones in a short bunch in PETRA, the effects of the closed orbit distortion y co and the dispersion η on a beam instability is studied with a two-particle model. It follows the result which supports Kohaupt's previous results; they hardly contribute to real tune shift, while the momentum dependence of the wake force can make a beam unstable, with the growth rate which is proportional to the product of y co and η. (orig.)
Effects on Ion Cyclotron Emission of the Orbit Topology Changes from the Wave-Particle Interactions
International Nuclear Information System (INIS)
Hellsten, T.; Holmstroem, K.; Johnson, T.; Bergkvist, T.; Laxaback, M.
2006-01-01
It is known that non-relaxed distribution functions can give rise to excitation of magnetosonic waves by ion cyclotron interactions when the distribution function increases with respect to the perpendicular velocity. We have found that in a toroidal plasma also collisional relaxed distribution functions of central peaked high-energy ions can destabilise magnetosonic eigenmodes by ion cyclotron interactions, due to the change in localisation of the orbits establishing inverted distribution functions with respect to energy along the characteristics describing the cyclotron interactions. This can take place by interactions with barely co-passing and marginally trapped high-energy ions at the plasma boundary. The interactions are enhanced by tangential interactions, which can also prevent the interactions to reach the stable part of the characteristics where they interact with more deeply trapped orbits. (author)
Sun, Wenbo; Hu, Yongxiang; Weimer, Carl; Ayers, Kirk; Baize, Rosemary R.; Lee, Tsengdar
2017-02-01
Electromagnetic (EM) beams with orbital angular momentum (OAM) may have great potential applications in communication technology and in remote sensing of the Earth-atmosphere system and outer planets. Study of their interaction with optical lenses and dielectric or metallic objects, or scattering of them by particles in the Earth-atmosphere system, is a necessary step to explore the advantage of the OAM EM beams. In this study, the 3-dimensional (3D) scattered-field (SF) finite-difference time domain (FDTD) technique with the convolutional perfectly matched layer (CPML) absorbing boundary conditions (ABC) is applied to calculate the scattering of the purely azimuthal (the radial mode number is assumed to be zero) Laguerre-Gaussian (LG) beams with the OAM by dielectric particles. We found that for OAM beam's interaction with dielectric particles, the forward-scattering peak in the conventional phase function (P11) disappears, and light scattering peak occurs at a scattering angle of 15° to 45°. The disappearance of forward-scattering peak means that, in laser communications most of the particle-scattered noise cannot enter the receiver, thus the received light is optimally the original OAM-encoded signal. This feature of the OAM beam also implies that in lidar remote sensing of the atmospheric particulates, most of the multiple-scattering energy will be off lidar sensors, and this may result in an accurate profiling of particle layers in the atmosphere or in the oceans by lidar, or even in the ground when a ground penetration radar (GPR) with the OAM is applied. This far-field characteristics of the scattered OAM light also imply that the optical theorem, which is derived from plane-parallel wave scattering case and relates the forward scattering amplitude to the total cross section of the scatterer, is invalid for the scattering of OAM beams by dielectric particles.
Krizmanic, John F.; Mitchell, John W.; Streitmatter, Robert E.
2013-01-01
OWL [1] uses the Earth's atmosphere as a vast calorimeter to fully enable the emerging field of charged-particle astronomy with high-statistics measurements of ultra-high-energy cosmic rays (UHECR) and a search for sources of UHE neutrinos and photons. Confirmation of the Greisen-Zatsepin-Kuzmin (GZK) suppression above approx. 4 x 10(exp 19) eV suggests that most UHECR originate in astrophysical objects. Higher energy particles must come from sources within about 100 Mpc and are deflected by approx. 1 degree by predicted intergalactic/galactic magnetic fields. The Pierre Auger Array, Telescope Array and the future JEM-EUSO ISS mission will open charged-particle astronomy, but much greater exposure will be required to fully identify and measure the spectra of individual sources. OWL uses two large telescopes with 3 m optical apertures and 45 degree FOV in near-equatorial orbits. Simulations of a five-year OWL mission indicate approx. 10(exp 6) sq km/ sr/ yr of exposure with full aperture at approx. 6 x 10(exp 19) eV. Observations at different altitudes and spacecraft separations optimize sensitivity to UHECRs and neutrinos. OWL's stereo event reconstruction is nearly independent of track inclination and very tolerant of atmospheric conditions. An optional monocular mode gives increased reliability and can increase the instantaneous aperture. OWL can fully reconstruct horizontal and upward-moving showers and so has high sensitivity to UHE neutrinos. New capabilities in inflatable structures optics and silicon photomultipliers can greatly increase photon sensitivity, reducing the energy threshold for n detection or increasing viewed area using a higher orbit. Design trades between the original and optimized OWL missions and the enhanced science capabilities are described.
Rapid Frequency Chirps of TAE mode due to Finite Orbit Energetic Particles
Berk, Herb; Wang, Ge
2013-10-01
The tip model for the TAE mode in the large aspect ratio limit, conceived by Rosenbluth et al. in the frequency domain, together with an interaction term in the frequency domain based on a map model, has been extended into the time domain. We present the formal basis for the model, starting with the Lagrangian for the particle wave interaction. We shall discuss the formal nonlinear time domain problem and the procedure that needs to obtain solutions in the adiabatic limit.
International Nuclear Information System (INIS)
Tomomura, Kiyoshi; Kato, Yoshio; Sakurai, Tohru
1982-01-01
Characteristics of flux variations of energetic particles associated with Storm Sudden Commencement (SSC) are examined on the basis of the particle's data observed by solid state detecter onboard the synchronous satellite, GMS ''Himawari'', during the period from Febuary 1978 to August 1979. The energy of the particles are covered from 1.2 to 4.0 MeV for proton and greater than 2 MeV for electron, respectively. The flux variations for protons generally increase in association with SSC. However, for electrons, they show the increase except 7 events (the decrease event) among 40 events studied. It is evident that the values of the flux attained immediately after SSC (J) clearly depend on those just before SSC(J 0 ). They follow a Power law (J proportional J 0 sup( n)). The variation of the proton flux ( + ΔJ + = + J - J 0+ ) increases with the value of the flux just before SSC. In both increase and decrease events for electrons, the variation of the flux tends to increase until the flux just before SSC attains the value of 10 4 , then to decrease as its value exceeds 10 4 . (author)
Kohno, M; Fujita, T; Nakamoto, C; Suzuki, Y
2000-01-01
Using the SU sub 6 quark-model baryon-baryon interaction which was recently developed by the Kyoto-Niigata group, we calculate N N, LAMBDA N and SIGMA N G--matrices in ordinary nuclear matter. Following the Scheerbaum's prescription, the strength of the single-particle spin-orbit potential S sub B is quantitatively discussed. The S subLAMBDA becomes small because of the cancellation between spin-orbit and anti-symmetric spin-orbit components. The short-range correlation is found to further reduce S subLAMBDA.
Tuzzolino, A. J.; Simpson, J. A.; Mckibben, R. B.; Voss, H. D.; Gursky, H.
1993-01-01
The characteristics of a space dust instrument which would be ideally suited to carry out near-Earth dust measurements on a possible Long Duraction Exposure Facility reflight mission (LDEF 2) is discussed. As a model for the trajectory portion of the instrument proposed for LDEF 2, the characteristics of a SPAce DUSt instrument (SPADUS) currently under development for flight on the USA ARGOS mission to measure the flux, mass, velocity, and trajectory of near-Earth dust is summarized. Since natural (cosmic) dust and man-made dust particles (orbital debris) have different velocity and trajectory distributions, they are distinguished by means of the SPADUS velocity/trajectory information. The SPADUS measurements will cover the dust mass range approximately 5 x 10(exp -12) g (2 microns diameter) to approximately 1 x 10(exp -5) g (200 microns diameter), with an expected mean error in particle trajectory of approximately 7 deg (isotropic flux). Arrays of capture cell devices positioned behind the trajectory instrumentation would provide for Earth-based chemical and isotopic analysis of captured dust. The SPADUS measurement principles, characteristics, its role in the ARGOS mission, and its application to an LDEF 2 mission are summarized.
International Nuclear Information System (INIS)
Gao Fei; Gao Hongrui; Li Zhuoqiu; Tong Hengqing; Lee, Ju-Jang
2009-01-01
It is well known that set of unstable periodic orbits (UPOs) can be thought of as the skeleton for the dynamics. However, detecting UPOs of nonlinear map is one of the most challenging problems of nonlinear science in both numerical computations and experimental measures. In this paper, a new method is proposed to detect the UPOs in a non-Lyapunov way. Firstly three special techniques are added to quantum-behaved particle swarm optimization (QPSO), a novel mbest particle, contracting the searching space self-adaptively and boundaries restriction (NCB), then the new method NCB-QPSO is proposed. It can maintain an effective search mechanism with fine equilibrium between exploitation and exploration. Secondly, the problems of detecting the UPOs are converted into a non-negative functions' minimization through a proper translation in a non-Lyapunov way. Thirdly the simulations to 6 benchmark optimization problems and different high order UPOs of 5 classic nonlinear maps are done by the proposed method. And the results show that NCB-QPSO is a successful method in detecting the UPOs, and it has the advantages of fast convergence, high precision and robustness.
International Nuclear Information System (INIS)
Horn, F.L.; Powell, J.R.; Lazareth, O.W.
1986-01-01
The particle bed reactor designed for 100 to 300 MW power output using hydrogen as a coolant is capable of specific impulses up to 1000 seconds as a nuclear rocket. A single space shuttle compatible vehicle can perform extensive missions from LEO to 3 times GEO and return with multi-ton payloads. The use of hydrogen to directly cool particulate reactor fuel results in a compact, lightweight rocket vehicle, whose duration of usefulness is dependent only upon hydrogen resupply availability. The LEO to GEO mission had a payload capability of 15.4 metric tons with 3.4 meters of shuttle bay. To increase the volume limitation of the shuttle bay, the use of ammonia in the initial boost phase from LEO is used to give greater payload volume with a small decrease in payload mass, 8.7 meters and 12.7 m-tons. 5 refs., 15 figs
International Nuclear Information System (INIS)
Bianchi, L.
1969-01-01
A table of charged particle energies versus magnetic field strength x orbit radius (B ρ ) is presented. Particles p, d, t, 3 He ++ , 4 He + , 4 He ++ , 6 Li + , 6 Li ++ , 6 Li +++ , 7 Li + , 7 Li ++ , 7 Li +++ . Values of B ρ : 100 to 1200 kG.cm by steps of 0.5 kG.cm. Values of energies are given in keV. (author) [fr
Parra, Pablo; da Silva, Antonio; Polo, Óscar R.; Sánchez, Sebastián
2018-02-01
In this day and age, successful embedded critical software needs agile and continuous development and testing procedures. This paper presents the overall testing and code coverage metrics obtained during the unit testing procedure carried out to verify the correctness of the boot software that will run in the Instrument Control Unit (ICU) of the Energetic Particle Detector (EPD) on-board Solar Orbiter. The ICU boot software is a critical part of the project so its verification should be addressed at an early development stage, so any test case missed in this process may affect the quality of the overall on-board software. According to the European Cooperation for Space Standardization ESA standards, testing this kind of critical software must cover 100% of the source code statement and decision paths. This leads to the complete testing of fault tolerance and recovery mechanisms that have to resolve every possible memory corruption or communication error brought about by the space environment. The introduced procedure enables fault injection from the beginning of the development process and enables to fulfill the exigent code coverage demands on the boot software.
Effects of the radial electrical field on the drifts, trapping and particle orbits in TJ-II
International Nuclear Information System (INIS)
Guasp, J.; Liniers, M.
1997-01-01
In this study a detailed analysis of the effect of radial electric fields on drifts, trapping and trajectories for ions of low and intermediate energy (0.1-1 keV) in the helical axis stellarator TJ-II has been performed. In TJ-II the drift velocities have the same rotation direction than the Hard Core (HC, the same than the plasma) with predominance of the vertical downwards component. The intensity is higher near the HC and in the outwards direction. These trends create strong asymmetries in losses even in the absence of electric field. When an electric field is present the poloidal components of the drift velocity predominates modifying deeply the orbit behaviour. Positive electric fields produce internal radial trapping barriers and have a tendency to eliminate the external ones. The opposite happens for negative fields. These facts alterate deeply the tapping and confinement properties of the particles. All these analysis will be used as a basis for the understanding of the modifications on the loss distribution, trapping regions and loss cones for TJ-II that will be addressed in forthcoming studies. (Author)
International Nuclear Information System (INIS)
Guseinov, I.I.
2007-01-01
The new analytical relations of complete orthonormal sets for the tensor wave functions and the tensor Slater orbitals of particles with arbitrary spin in coordinate, momentum and four-dimensional spaces are derived using the properties of tensor spherical harmonics and complete orthonormal scalar basis sets of ψ α -exponential type orbitals, φ α -momentum space orbitals and z α -hyperspherical harmonics introduced by the author for particles with spin s=0, where the α=1,0,-1,-2,.... All of the tensor wave functions obtained are complete without the inclusion of the continuum and, therefore, their group of transformations is the four-dimensional rotation group O(4). The analytical formulas in coordinate space are also derived for the overlap integrals over tensor Slater orbitals with the same screening constant. We notice that the new idea presented in this work is the combination of tensor spherical harmonics of rank s with complete orthonormal scalar sets for radial parts of ψ α -, φ α - and z α -orbitals, where s=1/2,1,3/2,2,...
Directory of Open Access Journals (Sweden)
Petrov Yuri V.
2017-01-01
Full Text Available The bounce-average (BA finite-difference Fokker-Planck (FP code CQL3D [1,2] now includes the essential physics to describe the RF heating of Finite-Orbit-Width (FOW ions in tokamaks. The FP equation is reformulated in terms of Constants-Of-Motion coordinates, which we select to be particle speed, pitch angle, and major radius on the equatorial plane thus obtaining the distribution function directly at this location. Full-orbit, low collisionality neoclassical radial transport emerges from averaging the local friction and diffusion coefficients along guiding center orbits. Similarly, the BA of local quasilinear RF diffusion terms gives rise to additional radial transport. The local RF electric field components needed for the BA operator are usually obtained by a ray-tracing code, such as GENRAY, or in conjunction with full-wave codes. As a new, practical application, the CQL3D-FOW version is used for simulation of alpha-particle heating by high-harmonic waves in ITER. Coupling of high harmonic or helicon fast waves power to electrons is a promising current drive (CD scenario for high beta plasmas. However, the efficiency of current drive can be diminished by parasitic channeling of RF power into fast ions, such as alphas, through finite Larmor-radius effects. We investigate possibilities to reduce the fast ion heating in CD scenarios.
International Nuclear Information System (INIS)
Raepsaet, X.; Proust, E.; Gervaise, F.; Baraer, L.; Naury, S.; Linet, F.L.
1995-01-01
MAPS, a 3-year study program on NTP has recently been launched at CEA following the conclusions of a preliminary scoping study of an NTP system for earth to moon orbit cargo shuttle missions. This paper presents the main results of this scoping study, and gives an outline of the MAPS program. (authors). 5 figs., 11 tabs., 7 refs
Energy Technology Data Exchange (ETDEWEB)
Raepsaet, X; Proust, E; Gervaise, F; Baraer, L; Naury, S; Linet, F L [CEA Centre d` Etudes de Saclay, 91 - Gif-sur-Yvette (France). Dept. de Mecanique et de Technologie; Bresson, C F; Coriolis, C.C. de; Bergeron, I T.A.; Bourquin, L V; Clech, L V; Devaux, L V; Chevillot, L V; Augier, E V [EAMEA, 50 - Cherbourg (France)
1995-12-01
MAPS, a 3-year study program on NTP has recently been launched at CEA following the conclusions of a preliminary scoping study of an NTP system for earth to moon orbit cargo shuttle missions. This paper presents the main results of this scoping study, and gives an outline of the MAPS program. (authors). 5 figs., 11 tabs., 7 refs.
Freeman, S. J.; Sharp, D. K.; McAllister, S. A.; Kay, B. P.; Deibel, C. M.; Faestermann, T.; Hertenberger, R.; Mitchell, A. J.; Schiffer, J. P.; Szwec, S. V.; Thomas, J. S.; Wirth, H.-F.
2017-11-01
The rearrangements of protons and neutrons amongst the valence single-particle orbitals during double-β decay of 100Mo have been determined by measuring cross sections in (d ,p ), (p ,d ), (3He,α ), and (3He,d ) reactions on Mo,10098 and Ru,102100 targets. The deduced nucleon occupancies reveal significant discrepancies when compared with theoretical calculations; the same calculations have previously been used to determine the nuclear matrix element associated with the decay probability of double-β decay of the 100Mo system.
De Becker, M.; Sana, H.; Absil, O.; Le Bouquin, J.-B.; Blomme, R.
2012-01-01
Using optical long baseline interferometry, we resolved for the first time the two wide components of HD 167971, a candidate hierarchical triple system known to efficiently accelerate particles. Our multi-epoch Very Large Telescope Interferometer observations provide direct evidence for a
International Nuclear Information System (INIS)
Michelotti, L.
1995-01-01
The past fifteen years have witnessed a remarkable development of methods for analyzing single particle orbit dynamics in accelerators. Unlike their more classic counterparts, which act upon differential equations, these methods proceed by manipulating Poincare maps directly. This attribute makes them well matched for studying accelerators whose physics is most naturally modelled in terms of maps, an observation that has been championed most vigorously by Forest. In the following sections the author sketchs a little background, explains some of the physics underlying these techniques, and discusses the best computing strategy for implementing them in conjunction with modeling accelerators
Energy Technology Data Exchange (ETDEWEB)
Michelotti, L.
1995-01-01
The past fifteen years have witnessed a remarkable development of methods for analyzing single particle orbit dynamics in accelerators. Unlike their more classic counterparts, which act upon differential equations, these methods proceed by manipulating Poincare maps directly. This attribute makes them well matched for studying accelerators whose physics is most naturally modelled in terms of maps, an observation that has been championed most vigorously by Forest. In the following sections the author sketchs a little background, explains some of the physics underlying these techniques, and discusses the best computing strategy for implementing them in conjunction with modeling accelerators.
Hamilton, Douglas P.
2018-04-01
Solar radiation pressure is usually very effective at removing hazardous millimeter-sized debris from distant orbits around asteroidsand other small solar system bodies (Hamilton and Burns 1992). Theprimary loss mechanism, driven by the azimuthal component of radiationpressure, is eccentricity growth followed by a forced collision withthe central body. One large class of orbits, however, neatly sidestepsthis fate. Orbits oriented nearly perpendicular to the solar directioncan maintain their face-on geometry, oscillating slowly around a stableequilibrium orbit. These orbits, designated sunflower orbits, arerelated to terminator orbits studied by spacecraft mission designers(Broschart etal. 2014).Destabilization of sunflower orbits occurs only for particles smallenough that radiation pressure is some tens of percent the strength ofthe central body's direct gravity. This greatly enhanced stability,which follows from the inability of radiation incident normal to theorbit to efficiently drive eccentricities, presents a threat tospacecraft missions, as numerous dangerous projectiles are potentiallyretained in orbit. We have investigated sunflower orbits insupport of the New Horizons, Aida, and Lucy missions and find thatthese orbits are stable for hazardous particle sizes at asteroids,comets, and Kuiper belt objects of differing dimensions. Weinvestigate the sources and sinks for debris that might populate suchorbits, estimate timescales and equilibrium populations, and willreport on our findings.
Zhao, J.; Wijayaratne, K.; Butler, A.; Yang, J.; Malliakas, C. D.; Chung, D. Y.; Louca, D.; Kanatzidis, M. G.; van Wezel, J.; Chatterjee, U.
2017-09-01
We report an in-depth angle-resolved photoemission spectroscopy study on 2 H -TaS2 , a canonical incommensurate charge density wave (CDW) system. This study demonstrates that just as in related incommensurate CDW systems, 2 H -TaSe2 and 2 H -NbSe2 , the energy gap (ΔCDW) of 2 H -TaS2 is localized along the K -centered Fermi surface barrels and is particle-hole asymmetric. The persistence of ΔCDW even at temperatures higher than the CDW transition temperature TCDW in 2 H -TaS2 , reflects the similar pseudogap behavior observed previously in 2 H -TaSe2 and 2 H -NbSe2 . However, in sharp contrast to 2 H -NbSe2 , where ΔCDW is nonzero only in the vicinity of a few "hot spots" on the inner K -centered Fermi surface barrels, ΔCDW in 2 H -TaS2 is nonzero along the entirety of both K -centered Fermi surface barrels. Based on a tight-binding model, we attribute this dichotomy in the momentum dependence and the Fermi surface specificity of ΔCDW between otherwise similar CDW compounds to the different orbital orientations of their electronic states that participate in the CDW pairing. Our results suggest that the orbital selectivity plays a critical role in the description of incommensurate CDW materials.
International Nuclear Information System (INIS)
Ress, R.I.
1976-01-01
Charged particles are entrained in a predetermined direction, independent of their polarity, in a circular orbit by a magnetic field rotating at high speed about an axis in a closed cylindrical or toroidal vessel. The field may be generated by a cylindrical laser structure, whose beam is polygonally reflected from the walls of an excited cavity centered on the axis, or by high-frequency energization of a set of electromagnets perpendicular to the axis. In the latter case, a separate magnetostatic axial field limits the orbital radius of the particles. These rotating and stationary magnetic fields may be generated centrally or by individual magnets peripherally spaced along its circular orbit. Chemical or nuclear reactions can be induced by collisions between the orbiting particles and an injected reactant, or by diverting high-speed particles from one doughnut into the path of counterrotating particles in an adjoining doughnut
Titan Orbiter Aerorover Mission
Sittler Jr., E. C.; Acuna, M.; Burchell, M. J.; Coates, A.; Farrell, W.; Flasar, M.; Goldstein, B. E.; Gorevan, S.; Hartle, R. E.; Johnson, W. T. K.
2001-01-01
We propose a combined Titan orbiter and Titan Aerorover mission with an emphasis on both in situ and remote sensing measurements of Titan's surface, atmosphere, ionosphere, and magnetospheric interaction. The biological aspect of the Titan environment will be emphasized by the mission (i.e., search for organic materials which may include simple organics to 'amono' analogues of amino acids and possibly more complex, lightening detection and infrared, ultraviolet, and charged particle interactions with Titan's surface and atmosphere). An international mission is assumed to control costs. NASA will provide the orbiter, launch vehicle, DSN coverage and operations, while international partners will provide the Aerorover and up to 30% of the cost for the scientific instruments through collaborative efforts. To further reduce costs we propose a single PI for orbiter science instruments and a single PI for Aerorover science instruments. This approach will provide single command/data and power interface between spacecraft and orbiter instruments that will have redundant central DPU and power converter for their instruments. A similar approach could be used for the Aerorover. The mission profile will be constructed to minimize conflicts between Aerorover science, orbiter radar science, orbiter radio science, orbiter imaging science, and orbiter fields and particles (FP) science. Additional information is contained in the original extended abstract.
International Nuclear Information System (INIS)
Rome, J.A.; Peng, Y.K.M.
1978-09-01
Guiding center orbits in noncircular axisymmetric tokamak plasmas are studied in the constants of motion (COM) space of (v, zeta, psi/sub m/). Here, v is the particle speed, zeta is the pitch angle with respect to the parallel equilibrium current, J/sub parallels/, and psi/sub m/ is the maximum value of the poloidal flux function (increasing from the magnetic axis) along the guiding center orbit. Two D-shaped equilibria in a flux-conserving tokamak having β's of 1.3% and 7.7% are used as examples. In this space, each confined orbit corresponds to one and only one point and different types of orbits (e.g., circulating, trapped, stagnation and pinch orbits) are represented by separate regions or surfaces in the space. It is also shown that the existence of an absolute minimum B in the higher β (7.7%) equilibrium results in a dramatically different orbit topology from that of the lower β case. The differences indicate the confinement of additional high energy (v → c, within the guiding center approximation) trapped, co- and countercirculating particles whose orbit psi/sub m/ falls within the absolute B well
International Nuclear Information System (INIS)
Burko, Lior M
2006-01-01
Comparing the corrections to Kepler's law with orbital evolution under a self-force, we extract the finite, already regularized part of the latter in a specific gauge. We apply this method to a quasi-circular orbit around a Schwarzschild black hole of an extreme mass ratio binary, and determine the first- and second-order conservative gravitational self-force in a post-Newtonian expansion. We use these results in the construction of the gravitational waveform, and revisit the question of the relative contribution of the self-force and spin-orbit coupling
Directory of Open Access Journals (Sweden)
Anatoliy Klimyk
2006-01-01
Full Text Available In the paper, properties of orbit functions are reviewed and further developed. Orbit functions on the Euclidean space E_n are symmetrized exponential functions. The symmetrization is fulfilled by a Weyl group corresponding to a Coxeter-Dynkin diagram. Properties of such functions will be described. An orbit function is the contribution to an irreducible character of a compact semisimple Lie group G of rank n from one of its Weyl group orbits. It is shown that values of orbit functions are repeated on copies of the fundamental domain F of the affine Weyl group (determined by the initial Weyl group in the entire Euclidean space E_n. Orbit functions are solutions of the corresponding Laplace equation in E_n, satisfying the Neumann condition on the boundary of F. Orbit functions determine a symmetrized Fourier transform and a transform on a finite set of points.
Directory of Open Access Journals (Sweden)
Andrej Kansky
2002-12-01
Full Text Available Background. Orbit is involved in 40% of all facial fractures. There is considerable variety in severity, ranging from simple nondisplaced to complex comminuted fractures. Complex comminuted fractures (up to 20% are responsible for the majority of complications and unfavorable results. Orbital fractures are classified as internal orbital fractures, zygomatico-orbital fractures, naso-orbito-ethmoidal fractures and combined fractures. The ophtalmic sequelae of midfacial fractures are usually edema and ecchymosis of the soft tissues, subconjuctival hemorrhage, diplopia, iritis, retinal edema, ptosis, enophthalmos, ocular muscle paresis, mechanical restriction of ocular movement and nasolacrimal disturbances. More severe injuries such as optic nerve trauma and retinal detachments have also been reported. Within the wide range of orbital fractures small group of complex fractures causes most of the sequelae. Therefore identification of severe injuries and adequate treatment is of major importance. The introduction of craniofacial techniques made possible a wide exposure even of large orbital wall defects and their reconstruction by bone grafts. In spite of significant progress, repair of complex orbital wall defects remains a problem even for the experienced surgeons.Results. In 1999 121 facial injuries were treated at our department (Clinical Centre Ljubljana Dept. Of Maxillofacial and Oral Surgery. Orbit was involved in 65% of cases. Isolated inner orbital fractures presented 4% of all fractures. 17 (14% complex cases were treated, 5 of them being NOE, 5 orbital (frame and inner walls, 3 zygomatico-orbital, 2 FNO and 2 maxillo-orbital fractures.Conclusions. Final result of the surgical treatment depends on severity of maxillofacial trauma. Complex comminuted fractures are responsable for most of the unfavorable results and ocular function is often permanently damaged (up to 75% in these fractures.
Mouriaux, F; Coffin-Pichonnet, S; Robert, P-Y; Abad, S; Martin-Silva, N
2014-12-01
Orbital inflammation is a generic term encompassing inflammatory pathologies affecting all structures within the orbit : anterior (involvement up to the posterior aspect of the globe), diffuse (involvement of intra- and/or extraconal fat), apical (involvement of the posterior orbit), myositis (involvement of only the extraocular muscles), dacryoadenitis (involvement of the lacrimal gland). We distinguish between specific inflammation and non-specific inflammation, commonly referred to as idiopathic inflammation. Specific orbital inflammation corresponds to a secondary localization of a "generalized" disease (systemic or auto-immune). Idiopathic orbital inflammation corresponds to uniquely orbital inflammation without generalized disease, and thus an unknown etiology. At the top of the differential diagnosis for specific or idiopathic orbital inflammation are malignant tumors, represented most commonly in the adult by lympho-proliferative syndromes and metastases. Treatment of specific orbital inflammation begins with treatment of the underlying disease. For idiopathic orbital inflammation, treatment (most often corticosteroids) is indicated above all in cases of visual loss due to optic neuropathy, in the presence of pain or oculomotor palsy. Copyright © 2014 Elsevier Masson SAS. All rights reserved.
International Nuclear Information System (INIS)
Oertel, H. Jr.; Koerner, H.
1993-01-01
The Third Aerospace Symposium in Braunschweig presented, for the first time, the possibility of bringing together the classical disciplines of aerospace engineering and the natural science disciplines of meteorology and air chemistry in a european setting. In this way, aspects of environmental impact on the atmosphere could be examined quantitatively. An essential finding of the european conference, is the unrestricted agreement of the experts that the given launch frequencies of the present orbital transport result in a negligible amount of pollutants being released in the atmosphere. The symposium does, however, call attention to the increasing need to consider the effect of orbital and atmospheric environmental impact of a future increase in launch frequencies of orbital transport in connection with future space stations. The Third Aerospace Symposium, 'Orbital Transport, Technical, Meteorological and Chemical Aspects', constituted a first forum of discussion for engineers and scientists. Questions of new orbital transport technologies and their environmental impact were to be discussed towards a first consensus. Through the 34 reports and articles, the general problems of space transportation and environmental protection were addressed, as well as particular aspects of high temperatures during reentry in the atmosphere of the earth, precision navigation of flight vehicles or flow behavior and air chemistry in the stratosphere. (orig./CT). 342 figs
International Nuclear Information System (INIS)
Velasco-Martínez, D; Kunold, A; Cardoso, J L; Ibarra-Sierra, V G; Sandoval-Santana, J C
2014-01-01
In this paper we introduce an alternative approach to studying the motion of a planar charged particle subject to a static uniform magnetic field. It is well known that an electric charge under a uniform magnetic field has a planar motion if its initial velocity is perpendicular to the magnetic field. Although some constants of motion (CsM), as the energy and the angular momentum, have been widely discussed for this system, others have been neglected. We find that the angular momentum, the generator of the magnetic translations and the magnetic Laplace–Runge–Lenz vector are CsM for this particular system. We show also that these three quantities form an orthogonal basis of vectors. The present work addresses many aspects of the motion of a charged particle in a magnetic field that should be useful for students and tutors of the classical mechanics courses at the senior undergraduate level. (paper)
Wefel, John P.; Cooper, John F.
1990-01-01
The charged particle observations from Pioneer and Voyager at Saturn were reassessed with a view towards providing limits on the amount of unseen dust and debris that may exist in the Saturnian system. Such estimates are crucial for planning the Cassini tour of Saturn. The data from Pioneer 11 and Voyager were reviewed, intercompared, and correlated with model predictions to set limits on the matter distribution.
Yiǧitoǧlu, Merve; Veske, Doǧa; Nilüfer Öztürk, Zeynep; Bilge Demirköz, Melahat
2016-07-01
All devices which operate in space are exposed to cosmic rays during their operation. The resulting radiation may cause fatal damages in the solid structure of devices and the amount of absorbed radiation dose and secondary particle production for each component should be calculated carefully before the production. Solar panels are semiconductor solid state devices and are very sensitive to radiation. Even a short term power cut-off may yield a total failure of the satellite. Even little doses of radiation can change the characteristics of solar cells. This deviation can be caused by rarer high energetic particles as well as the total ionizing dose from the abundant low energy particles. In this study, solar panels planned for a specific LEO satellite, IMECE, are analyzed layer by layer. The Space Environment Information System (SPENVIS) database and GEANT4 simulation software are used to simulate the layers of the panels. The results obtained from the simulation will be taken in account to determine the amount of radiation protection and resistance needed for the panels or to revise the design of the panels.
International Nuclear Information System (INIS)
Heikkinen, J.A.; Henriksson, S.; Janhunen, S.; Kiviniemi, T.P.; Ogando, F.
2006-01-01
A full f nonlinear 5D gyrokinetic electrostatic particle-in-cell code ELMFIRE using an implicit direct solution method for ion polarization drift and electron parallel velocity response to electric field and its validation are described. The developed code is applied for transport analysis in a tokamak plasma at steep pressure gradient. The role of turbulence and neoclassical equilibrium in determining the flux surface averaged radial electric field component are investigated, as well as the role of the latter in affecting the saturation level of the turbulence. (copyright 2006 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)
International Nuclear Information System (INIS)
Maddox, L.B.; McNeilly, G.S.
1979-08-01
GOC (General Orbit Code) is a versatile program which will perform a variety of calculations relevant to isochronous cyclotron design studies. In addition to the usual calculations of interest (e.g., equilibrium and accelerated orbits, focusing frequencies, field isochronization, etc.), GOC has a number of options to calculate injections with a charge change. GOC provides both printed and plotted output, and will follow groups of particles to allow determination of finite-beam properties. An interactive PDP-10 program called GIP, which prepares input data for GOC, is available. GIP is a very easy and convenient way to prepare complicated input data for GOC. Enclosed with this report are several microfiche containing source listings of GOC and other related routines and the printed output from a multiple-option GOC run
International Nuclear Information System (INIS)
Musset, S.
2016-01-01
The Sun is an active star and one manifestation of its activity is the production of solar flares. It is currently admitted that solar flares are caused by the release of magnetic energy during the process of magnetic reconnection in the solar upper atmosphere, the solar corona. During these flares, a large fraction of the magnetic energy is transferred to the acceleration of particles (electrons and ions). However, the details of particle acceleration during flares are still not completely understood. Several scenarios and models have been developed to explain particle acceleration. In some of them, electric fields, produced at the location of current sheets, which can be fragmented or collapsing, and which are preferentially located on quasi-separatrix layers (QSLs), are accelerating particles. To investigate a possible link between energetic particles and direct electric fields produced at current sheet locations, we looked for a correlation between X-ray emission from energetic electrons and electric currents which can be measured at the photospheric level. We used the Reuven Ramaty High Energy Solar Spectrometric Imager (RHESSI) data to produce spectra and images of the X-ray emissions during GOES X-class flares, and spectro polarimetric data from the Helio seismic and Magnetic Imager (HMI) onboard the Solar Dynamics Observatory (SDO) to calculate the vertical current densities from the reconstructed 3D vector magnetic field. A correlation between the coronal X-ray emissions (tracing the energetic electrons near the acceleration site) and the strong current ribbons at the photospheric level (tracing the coronal current sheet) was found in the five studied X-class flares. Moreover, thanks to the 12-minute time cadence of SDO/HMI, we could study for the first time the time evolution of electric currents : in several flares, a change in the current intensity, occurring during the flare peak, was found to be spatially correlated with X-ray emission sites. These
Bergshoeff, Eric A; Riccioni, Fabio
2012-01-01
We complete the classification of half-supersymmetric branes in toroidally compactified IIA/IIB string theory in terms of representations of the T-duality group. As a by-product we derive a last wrapping rule for the space-filling branes. We find examples of T-duality representations of branes in lower dimensions, suggested by supergravity, of which none of the component branes follow from the reduction of any brane in ten-dimensional IIA/IIB string theory. We discuss the constraints on the charges of half-supersymmetric branes, determining the corresponding T-duality and U-duality orbits.
Nuclear propulsion for orbital transfer
International Nuclear Information System (INIS)
Beale, G.A.; Lawrence, T.J.
1989-01-01
The state of the art in nuclear propulsion for orbital transfer is discussed. Cryogenic propulsion, electric propulsion, solar-thermal propulsion and direct nuclear propulsion are examined in this context. New technologies with exceptional promise are addressed, emphasizing the particle test bed nuclear engine
Evaluation of the synchrotron close orbit
International Nuclear Information System (INIS)
Bashmakov, Yu.A.; Karpov, V.A.
1991-01-01
The knowledge of the closed orbit position is an essential condition for the effective work of any accelerator. Therefore questions of calculations, measurements and controls have great importance. For example, during injection of particles into a synchrotron, the amplitudes of their betatron oscillations may become commensurable with the working region of the synchrotron. This makes one pay attention at the problem of formation of the optimum orbit with use of correcting optical elements. In addition, it is often necessary to calculate such an orbit at the end of the acceleration cycle when particles are deposited at internal targets or removed from the synchrotron. In this paper, the computation of the close orbit is reduced to a determination at an arbitrarily chosen azimuth of the eigenvector of the total transfer matrix of the synchrotron ring and to tracing with this vector desired orbit. The eigenvector is found as a result of an iteration
International Nuclear Information System (INIS)
Imanishi, B.; Misono, S.; von Oertzen, W.; Voit, H.
1988-08-01
The molecular orbitals of the nucleon(s) in nucleus-nucleus collisions are dynamically defined as a linear combination of nucleon single-particle orbits (LCNO) in a rotating frame by using the coupled-reaction-channel (CRC) theory. Nucleon molecular orbitals and the promotions of nucleon, - especially due to the Landau-Zener radial coupling are discussed with the method above mentioned. (author)
Rosengren, Mats
1991-12-01
The European remote sensing mission orbit control is addressed. For the commissioning phase, the orbit is defined by the following requirements: Sun synchronous, local time of descending node 10:30; three days repeat cycle with 43 orbital revolutions; overhead Venice tower (12.508206 deg east, 45.314222 deg north). The launch, maneuvers for the initial acquisition of the operational orbit, orbit maintenance maneuvers, evaluation of the orbit control, and the drift of the inclination are summarized.
International Nuclear Information System (INIS)
Foster, Dean P; Langford, John; Perez-Giz, Gabe
2016-01-01
We study a spherically symmetric solution to the Einstein equations in which the source, which we call an orbiting radiation star (OR-star), is a compact object consisting of freely falling null particles. The solution avoids quantum scale regimes and hence neither relies upon nor ignores the interaction of quantum mechanics and gravitation. The OR-star spacetime exhibits a deep gravitational well yet remains singularity free. In fact, it is geometrically flat in the vicinity of the origin, with the flat region being of any desirable scale. The solution is observationally distinct from a black hole because a photon from infinity aimed at an OR-star escapes to infinity with a time delay. (paper)
Superbanana orbits in stellarator geometries
International Nuclear Information System (INIS)
Derr, J.A.; Shohet, J.L.
1979-04-01
The presence of superbanana orbit types localized to either the interior or the exterior of stellarators and torsatrons is numerically investigated for 3.5 MeV alpha particles. The absence of the interior superbanana in both geometries is found to be due to non-conservation of the action. Exterior superbananas are found in the stellarator only, as a consequence of the existence of closed helical magnetic wells. No superbananas of either type are found in the torsatron
African Journals Online (AJOL)
was done without contrast and 3mm/5mm/10mm slices were obtained to cover the orbit, skull base and brain. The findings included a soft tissue mass arising from the orbit. The left eye ball was extra orbital. There was no defect .... love's Short Practice of Surgery. 7 Edition,. Levis London, 1997; 45-64. 2. Orbital tumor Part 1, ...
International Nuclear Information System (INIS)
Abujamra, S.
1983-01-01
The authors present a method called ''Radiovolumetry of the orbit'' that permits the evaluation of the orbital volume from anteroposterior skull X-Rays (CALDWELL 30 0 position). The research was based in the determination of the orbital volume with lead spheres, in 1010 orbits of 505 dry skulls of Anatomy Museums. After the dry skulls was X-rayed six frontal orbital diameters were made, with care to correct the radiographic amplification. PEARSON correlation coeficient test was applied between the mean orbital diameter and the orbital volume. The result was r = 0,8 with P [pt
Collinson, Chris
1995-01-01
* Assumes no prior knowledge* Adopts a modelling approach* Numerous tutorial problems, worked examples and exercises included* Elementary topics augmented by planetary motion and rotating framesThis text provides an invaluable introduction to mechanicsm confining attention to the motion of a particle. It begins with a full discussion of the foundations of the subject within the context of mathematical modelling before covering more advanced topics including the theory of planetary orbits and the use of rotating frames of reference. Truly introductory , the style adoped is perfect for those u
A hybrid numerical method for orbit correction
International Nuclear Information System (INIS)
White, G.; Himel, T.; Shoaee, H.
1997-09-01
The authors describe a simple hybrid numerical method for beam orbit correction in particle accelerators. The method overcomes both degeneracy in the linear system being solved and respects boundaries on the solution. It uses the Singular Value Decomposition (SVD) to find and remove the null-space in the system, followed by a bounded Linear Least Squares analysis of the remaining recast problem. It was developed for correcting orbit and dispersion in the B-factory rings
Discrete symmetries in periodic-orbit theory
International Nuclear Information System (INIS)
Robbins, J.M.
1989-01-01
The application of periodic-orbit theory to systems which possess a discrete symmetry is considered. A semiclassical expression for the symmetry-projected Green's function is obtained; it involves a sum over classical periodic orbits on a symmetry-reduced phase space, weighted by characters of the symmetry group. These periodic orbits correspond to trajectories on the full phase space which are not necessarily periodic, but whose end points are related by symmetry. If the symmetry-projected Green's functions are summed, the contributions of the unperiodic orbits cancel, and one recovers the usual periodic-orbit sum for the full Green's function. Several examples are considered, including the stadium billiard, a particle in a periodic potential, the Sinai billiard, the quartic oscillator, and the rotational spectrum of SF 6
Theory of orbital magnetoelectric response
International Nuclear Information System (INIS)
Malashevich, Andrei; Souza, Ivo; Coh, Sinisa; Vanderbilt, David
2010-01-01
We extend the recently developed theory of bulk orbital magnetization to finite electric fields, and use it to calculate the orbital magnetoelectric (ME) response of periodic insulators. Working in the independent-particle framework, we find that the finite-field orbital magnetization can be written as a sum of three gauge-invariant contributions, one of which has no counterpart at zero field. The extra contribution is collinear with and explicitly dependent on the electric field. The expression for the orbital magnetization is suitable for first-principles implementations, allowing one to calculate the ME response coefficients by numerical differentiation. Alternatively, perturbation-theory techniques may be used, and for that purpose we derive an expression directly for the linear ME tensor by taking the first field-derivative analytically. Two types of terms are obtained. One, the 'Chern-Simons' term, depends only on the unperturbed occupied orbitals and is purely isotropic. The other, 'Kubo' terms, involve the first-order change in the orbitals and give isotropic as well as anisotropic contributions to the response. In ordinary ME insulators all terms are generally present, while in strong Z 2 topological insulators only the Chern-Simons term is allowed, and is quantized. In order to validate the theory, we have calculated under periodic boundary conditions the linear ME susceptibility for a 3D tight-binding model of an ordinary ME insulator, using both the finite-field and perturbation-theory expressions. The results are in excellent agreement with calculations on bounded samples.
Orbital Debris and NASA's Measurement Program
Africano, J. L.; Stansbery, E. G.
2002-05-01
Since the launch of Sputnik in 1957, the number of manmade objects in orbit around the Earth has dramatically increased. The United States Space Surveillance Network (SSN) tracks and maintains orbits on over nine thousand objects down to a limiting diameter of about ten centimeters. Unfortunately, active spacecraft are only a small percentage ( ~ 7%) of this population. The rest of the population is orbital debris or ``space junk" consisting of expended rocket bodies, dead payloads, bits and pieces from satellite launches, and fragments from satellite breakups. The number of these smaller orbital debris objects increases rapidly with decreasing size. It is estimated that there are at least 130,000 orbital debris objects between one and ten centimeters in diameter. Most objects smaller than 10 centimeters go untracked! As the orbital debris population grows, the risk to other orbiting objects, most importantly manned space vehicles, of a collision with a piece of debris also grows. The kinetic energy of a solid 1 cm aluminum sphere traveling at an orbital velocity of 10 km/sec is equivalent to a 400 lb. safe traveling at 60 mph. Fortunately, the volume of space in which the orbiting population resides is large, collisions are infrequent, but they do occur. The Space Shuttle often returns to earth with its windshield pocked with small pits or craters caused by collisions with very small, sub-millimeter-size pieces of debris (paint flakes, particles from solid rocket exhaust, etc.), and micrometeoroids. To get a more complete picture of the orbital-debris environment, NASA has been using both radar and optical techniques to monitor the orbital debris environment. This paper gives an overview of the orbital debris environment and NASA's measurement program.
Borumandi, Farzad
2013-01-01
Compared to the cerebrospinalfluid (CSF) leak through the nose and ear, the orbital CSF leak is a rare and underreported condition following head trauma. We present the case of a 49-year-old woman with oedematous eyelid swelling and ecchymosis after a seemingly trivial fall onto the right orbit. Apart from the above, she was clinically unremarkable. The CT scan revealed a minimally displaced fracture of the orbital roof with no emphysema or intracranial bleeding. The fractured orbital roof in combination with the oedematous eyelid swelling raised the suspicion for orbital CSF leak. The MRI of the neurocranium demonstrated a small-sized CSF fistula extending from the anterior cranial fossa to the right orbit. The patient was treated conservatively and the lid swelling resolved completely after 5 days. Although rare, orbital CSF leak needs to be included in the differential diagnosis of periorbital swelling following orbital trauma. PMID:24323381
Neutron stars with orbiting light
International Nuclear Information System (INIS)
Lukacs, B.
1987-11-01
There is a wide-spread belief in the literature of relativistic astrophysics concerning nonsingular final states of the stellar evolution: the external gravitational field of a physically nonsingular central symmetric body (e.g. a neutron star) is asymptotically empty and simple, i.e. there are no closed or trapped light-like causal geodesics. Present paper shows that this belief is false: some examples are presented for nonsingular bodies with various equations of state, around which there are closed light-like trajectories: 'orbiting light'. The reality of the used equations of state is discussed in detail. Present state of particle physics does not establish the existence of matter with such equations of state, but the hypothetical subquark level of matter may have such equation of state, thus 'subquark-stars' may exist with orbiting light around them. So the criterion of 'nonsingularity' must be further analyzed and accurately defined. (D.Gy.) 24 refs.; 5 figs
International Nuclear Information System (INIS)
Panfilova, G.V.; Koval', G.Yu.
1984-01-01
Radioanatomy of eyes and orbit is described. Diseases of the orbit (developmental anomalies, inflammatory diseases, lacrimal apparatus deseases, toxoplasmosis, tumors and cysts et al.), methods of foreign body localization in the eye are considered. Roentgenograms of the orbit and calculation table for foreign body localization in spherical eyes of dissimilar diameter are presented
Introducing Earth's Orbital Eccentricity
Oostra, Benjamin
2015-01-01
Most students know that planetary orbits, including Earth's, are elliptical; that is Kepler's first law, and it is found in many science textbooks. But quite a few are mistaken about the details, thinking that the orbit is very eccentric, or that this effect is somehow responsible for the seasons. In fact, the Earth's orbital eccentricity is…
Topology and slowing down of high energy ion orbits
Energy Technology Data Exchange (ETDEWEB)
Eriksson, L G [Commission of the European Communities, Abingdon (United Kingdom). JET Joint Undertaking; Porcelli, F [Politecnico di Torino, Turin (Italy); Berk, H L [Texas Univ., Austin, TX (United States). Inst. for Fusion Studies
1994-07-01
An analysis of nonstandard guiding centre orbits is presented, which is relevant to MeV ions in a Tokamak. The orbit equation has been simplified from the start, allowing to present an analytic classification of the possible orbits. The topological transitions of the orbits during collisional slowing down are described. In particular, the characteristic equations reveal the existence of a single fixed point in the relevant phase plane, and the presence of a bifurcation curve corresponding to the locus of the pinch orbits. A significant particle inward pinch has been discovered. (authors). 7 figs.
Microscopic Stern-Gerlach effect and spin-orbit pendulum
International Nuclear Information System (INIS)
Rozmej, P.; Arvieu, R.
1996-01-01
The motion of a particle with spin in spherical harmonic oscillator potential with spin-orbit interaction is discussed. The attention is focused on the spatial motion of wave packets. The particular case of wave packets moving along the circular orbits for which the most transparent and pedagogical description is possible is considered. The splitting of the wave packets into two components moving differently along classical orbits reflects a strong analogy with the Stern-Gerlach experiment. The periodic transfer of average angular momentum between spin and orbital subspaces accompanying this time evolution is called the spin-orbit pendulum. (author). 6 refs, 3 figs
Space station orbit maintenance
Kaplan, D. I.; Jones, R. M.
1983-01-01
The orbit maintenance problem is examined for two low-earth-orbiting space station concepts - the large, manned Space Operations Center (SOC) and the smaller, unmanned Science and Applications Space Platform (SASP). Atmospheric drag forces are calculated, and circular orbit altitudes are selected to assure a 90 day decay period in the event of catastrophic propulsion system failure. Several thrusting strategies for orbit maintenance are discussed. Various chemical and electric propulsion systems for orbit maintenance are compared on the basis of propellant resupply requirements, power requirements, Shuttle launch costs, and technology readiness.
Nontraumatic orbital roof encephalocele.
Hoang, Amber; Maugans, Todd; Ngo, Thang; Ikeda, Jamie
2017-02-01
Intraorbital meningoencephaloceles occur most commonly as a complication of traumatic orbital roof fractures. Nontraumatic congenital orbital meningoncephaloceles are very rare, with most secondary to destructive processes affecting the orbit and primary skull defects. Treatment for intraorbital meningoencephaloceles is surgical repair, involving the excision of herniated brain parenchyma and meninges and reconstruction of the osseous defect. Most congenital lesions present in infancy with obvious globe and orbital deformities; we report an orbital meningoencephalocele in a 3-year-old girl who presented with ptosis. Copyright © 2017 American Association for Pediatric Ophthalmology and Strabismus. Published by Elsevier Inc. All rights reserved.
Directory of Open Access Journals (Sweden)
Jeffrey M Joseph
2011-01-01
Full Text Available Jeffrey M Joseph, Ioannis P GlavasDivision of Ophthalmic Plastic and Reconstructive Surgery, Department of Ophthalmology, School of Medicine, New York University, New York, NY, USA; Manhattan Eye, Ear, and Throat Hospital, New York, NY, USAAbstract: This review of orbital fractures has three goals: 1 to understand the clinically relevant orbital anatomy with regard to periorbital trauma and orbital fractures, 2 to explain how to assess and examine a patient after periorbital trauma, and 3 to understand the medical and surgical management of orbital fractures. The article aims to summarize the evaluation and management of commonly encountered orbital fractures from the ophthalmologic perspective and to provide an overview for all practicing ophthalmologists and ophthalmologists in training.Keywords: orbit, trauma, fracture, orbital floor, medial wall, zygomatic, zygomatic complex, zmc fracture, zygomaticomaxillary complex fractures
Transport from chaotic orbits in the geomagnetic tail
International Nuclear Information System (INIS)
Horton, W.; Tajima, T.
1991-01-01
The rapid change in direction and magnitude of the magnetic field vector in crossing the quasineutral sheet in the geomagnetic tail leads to deterministic Hamiltonian chaos. The finite correlation times in the single particle orbits due to the continuum of orbital frequencies leads to well-defined collisionless transport coefficients. The transport coefficients are derived for plasma trapped in the quasineutral sheet
Orbit losses of strongly ICRF-heated ions
International Nuclear Information System (INIS)
Anderson, A.; Dillner, Oe.; Lisak, M.
1992-01-01
An approximate analytical investigation is made to assess the importance of orbit losses of strongly ICRF-heated minority ions. Explicit expressions for the fraction of lost minority ions are derived and shown to be in good agreement with numerical simulation results. The results indicate that present day ICRF heating power density levels cannot be raised significantly without causing important particle and energy losses due to unconfined particle orbits. 6 refs., 5 figs
Aiyub, Shereen; Chan, Weng Onn; Szetu, John; Sullivan, Laurence J; Pater, John; Cooper, Peter; Selva, Dinesh
2013-01-01
We present a case of mature congenital orbital teratoma managed with lid-sparing exenteration and dermis fat graft. This is a case report on the management of congenital orbital teratoma. A full-term baby was born in Fiji with prolapsed right globe which was surrounded by a nonpulsatile, cystic mass. Clinical and imaging features were consistent with congenital orbital teratoma. Due to limited surgical expertise, the patient was transferred to Adelaide, Australia for further management. The p...
Pictorial essay: Orbital tuberculosis
International Nuclear Information System (INIS)
Narula, Mahender K; Chaudhary, Vikas; Baruah, Dhiraj; Kathuria, Manoj; Anand, Rama
2010-01-01
Tuberculosis of the orbit is rare, even in places where tuberculosis is endemic. The disease may involve soft tissue, the lacrimal gland, or the periosteum or bones of the orbital wall. Intracranial extension, in the form of extradural abscess, and infratemporal fossa extension has been described. This pictorial essay illustrates the imaging findings of nine histopathologically confirmed cases of orbital tuberculosis. All these patients responded to antituberculous treatment
International Nuclear Information System (INIS)
Kelly, J.K.; Lazo, A.; Metes, J.J.
1988-01-01
Computed tomography has become the gold standard against which to measure orbital imaging modalities. The simultaneous display of bone, soft tissues, paranasal sinuses, and intracranial structures is a unique advantage. Radiation dose and cost have been cited as disadvantages. These would suggest that CT be reserved for the patient with significant orbital injury or difficult diagnostic problems. Magnetic resonance is limited in the investigation of orbital trauma
Directory of Open Access Journals (Sweden)
Khalil M Al-Salem
2014-01-01
Full Text Available Orbital complications due to ethmoiditis are rare in neonates. A case of orbital abscess due to acute ethmoiditis in a 28-day-old girl is presented. A Successful outcome was achieved following antimicrobial therapy alone; spontaneous drainage of the abscess occurred from the lower lid without the need for surgery. From this case report, we intend to emphasize on eyelid retraction as a sign of neonatal orbital abscess, and to review all the available literature of similar cases.
International Nuclear Information System (INIS)
Kusmartsev, F.V.
1992-10-01
The physical reasons why the orbital glass may exist in granular high-temperature superconductors and the existing experimental data appeared recently are discussed. The orbital glass is characterized by the coexistence of the orbital paramagnetic state with the superconducting state and occurs at small magnetic fields H c0 c1 . The transition in orbital glass arises at the critical field H c0 which is inversely proportional to the surface cross-area S of an average grain. In connection with theoretical predictions the possible experiments are proposed. (author). 10 refs
Czech Academy of Sciences Publication Activity Database
Veselý, Petr; Hiyama, E.; Hrtánková, Jaroslava; Mareš, Jiří
2016-01-01
Roč. 954, OCT (2016), s. 260-272 ISSN 0375-9474 R&D Projects: GA ČR(CZ) GA15-04301S Grant - others:GA MŠk(CZ) LM2010005 Institutional support: RVO:61389005 Keywords : Lambda hypernuclei * spin orbit spilitting * Lambda N interaction * mean field model Subject RIV: BE - Theoretical Physics Impact factor: 1.916, year: 2016
Sotiriou-Leventis, Chariklia; Hanna, Samir B.; Leventis, Nicholas
1996-04-01
The well-accepted practice of generating a pair of molecular orbitals, one of lower energy and another of higher energy than the original pair of overlapping atomic orbitals, and the concept of a particle in a one-dimensional box are implemented in a simplified, nonmathematical method that explains the relative stabilities and reactivities of alkenes with conjugated versus isolated double bonds. In this method, Huckel-type MO's of higher polyenes are constructed by energy rules of linear combination of atomic orbitals. One additional rule is obeyed: bonding molecular orbitals overlap only with bonding molecular orbitals, and antibonding molecular orbitals overlap only with antibonding molecular orbitals.
Congenital orbital encephalocele, orbital dystopia, and exophthalmos.
Hwang, Kun; Kim, Han Joon
2012-07-01
We present here an exceedingly rare variant of a nonmidline basal encephalocele of the spheno-orbital type, and this was accompanied with orbital dystopia in a 56-year-old man. On examination, his left eye was located more inferolaterally than his right eye, and the patient said this had been this way since his birth. The protrusion of his left eye was aggravated when he is tired. His naked visual acuity was 0.7/0.3, and the ocular pressure was 14/12 mm Hg. The exophthalmometry was 10/14 to 16 mm. His eyeball motion was not restricted, yet diplopia was present in all directions. The distance from the midline to the medial canthus was 20/15 mm. The distance from the midline to the midpupillary line was 35/22 mm. The vertical dimension of the palpebral fissure was 12/9 mm. The height difference of the upper eyelid margin was 11 mm, and the height difference of the lower eyelid margin was 8 mm. Facial computed tomography and magnetic resonance imaging showed left sphenoid wing hypoplasia and herniation of the left anterior temporal pole and dura mater into the orbit, and this resulted into left exophthalmos and encephalomalacia in the left anterior temporal pole. To the best of our knowledge, our case is the second case of basal encephalocele and orbital dystopia.
Orbital and adnexal sarcoidosis
Prabhakaran, Venkatesh C.; Saeed, Perooz; Esmaeli, Bita; Sullivan, Timothy J.; Mcnab, Alan; Davis, Garry; Valenzuela, Alejandra; Leibovitch, Igal; Kesler, Anat; Sivak-Callcott, Jennifer; Hoyama, Erika; Selva, Dinesh
2007-01-01
To present the clinical features and management in a series of patients with orbital and adnexal sarcoidosis. This multicenter retrospective study included patients with biopsy-proven noncaseating granuloma involving the orbit or adnexa and evidence of systemic sarcoidosis. Clinical records were
Update on orbital reconstruction.
Chen, Chien-Tzung; Chen, Yu-Ray
2010-08-01
Orbital trauma is common and frequently complicated by ocular injuries. The recent literature on orbital fracture is analyzed with emphasis on epidemiological data assessment, surgical timing, method of approach and reconstruction materials. Computed tomographic (CT) scan has become a routine evaluation tool for orbital trauma, and mobile CT can be applied intraoperatively if necessary. Concomitant serious ocular injury should be carefully evaluated preoperatively. Patients presenting with nonresolving oculocardiac reflex, 'white-eyed' blowout fracture, or diplopia with a positive forced duction test and CT evidence of orbital tissue entrapment require early surgical repair. Otherwise, enophthalmos can be corrected by late surgery with a similar outcome to early surgery. The use of an endoscope-assisted approach for orbital reconstruction continues to grow, offering an alternative method. Advances in alloplastic materials have improved surgical outcome and shortened operating time. In this review of modern orbital reconstruction, several controversial issues such as surgical indication, surgical timing, method of approach and choice of reconstruction material are discussed. Preoperative fine-cut CT image and thorough ophthalmologic examination are key elements to determine surgical indications. The choice of surgical approach and reconstruction materials much depends on the surgeon's experience and the reconstruction area. Prefabricated alloplastic implants together with image software and stereolithographic models are significant advances that help to more accurately reconstruct the traumatized orbit. The recent evolution of orbit reconstruction improves functional and aesthetic results and minimizes surgical complications.
International Nuclear Information System (INIS)
Iinuma, Toshitaka; Ishio, Ken-ichirou; Yoshinami, Hiroyoshi; Kuriyama, Jun-ichi; Hirota, Yoshiharu.
1993-01-01
A total of 59 cases of mild facial fractures (simple orbital wall fractures, 34 cases, other facial fractures, 25 cases) with the clinical suspects of orbital wall fractures were evaluated both by conventional views (Waters' and Caldwell views) and coronal CT scans. Conventional views were obtained, as an average, after 4 days and CT after 7 days of injuries. Both the medial wall and the floor were evaluated at two sites, i.e., anterior and posterior. The ethmoid-maxillary plate was also included in the study. The degree of fractures was classified as, no fractures, fractures of discontinuity, dislocation and fragmentation. The coronal CT images in bone window condition was used as reference and the findings were compared between conventional views and CT. The correct diagnosis was obtained as follows: orbital floor (anterior, 78%, posterior, 73%), medial orbital wall (anterior, 72%, posterior, 72%) and ethmoid-maxillary plate (64%). The false positive diagnosis was as follows: orbital floor (anterior only, 13%), medial orbital wall (anterior only, 7%) and ethmoid-maxillary plate (11%). The false negative diagnosis was as follows: orbital floor (anterior, 9%, posterior, 10%), medial orbital wall (anterior, 21%, posterior, 28%) and ethmoid-maxillary plate (21%). The results were compared with those of others in the past. (author)
Single-particle motion in rapidly rotating nuclei
International Nuclear Information System (INIS)
Bengtsson, R.; Frisk, H.
1985-01-01
The motion of particles belonging to a single-j shell is described in terms of classical orbitals. The effects of rapid rotation and pairing correlations are discussed and the results are compared with the quantum mechanical orbitals. (orig.)
Excitation of neutron star oscillations by an orbiting mass
International Nuclear Information System (INIS)
Ruoff, J.
2001-01-01
In this contribution, I present results from a numerical study of the even-parity gravitational radiation generated from a particle orbiting a neutron star. The investigation is focused on those conditions on the orbital parameters that favor the excitation of w-modes. It is found that, for astrophysically realistic conditions, there is practically no w-mode contribution to the emitted radiation. Only for particles with ultra-relativistic orbital speeds ≥ 0.9c, the w-mode does significantly contribute to the total emitted gravitational energy. To obtain reliable results, a way is presented to construct consistent initial data which contain as little as possible initial radiation. (author)
Hara, Yasuo
1975-01-01
Peripheral orbit model, in which an incoming hadron is assumed to revolve in a peripheral orbit around a target hadron, is discussed. The non-diffractive parts of two-body reaction amplitudes of hadrons are expressed in terms of the radius, width an absorptivity of the orbit. The radius of the orbit is about 1 fm and the width of the orbit is determined by the range of the interaction between the hadrons. The model reproduces all available experimental data on differential cross-sections and polarizations of $K^{-}p\\to K^{-}p$ and $\\bar K^{\\circ}n$ reactions for all angles successfully. This contribution is not included in the proceedings since it will appear in Progress of Theoretical Physics Vol. 51 (1974) No 2. Any person interested in the subject may apply for reprints to the author.
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Harmonically excited orbital variations
International Nuclear Information System (INIS)
Morgan, T.
1985-01-01
Rephrasing the equations of motion for orbital maneuvers in terms of Lagrangian generalized coordinates instead of Newtonian rectangular cartesian coordinates can make certain harmonic terms in the orbital angular momentum vector more readily apparent. In this formulation the equations of motion adopt the form of a damped harmonic oscillator when torques are applied to the orbit in a variationally prescribed manner. The frequencies of the oscillator equation are in some ways unexpected but can nonetheless be exploited through resonant forcing functions to achieve large secular variations in the orbital elements. Two cases are discussed using a circular orbit as the control case: (1) large changes in orbital inclination achieved by harmonic excitation rather than one impulsive velocity change, and (2) periodic and secular changes to the longitude of the ascending node using both stable and unstable excitation strategies. The implications of these equations are also discussed for both artificial satellites and natural satellites. For the former, two utilitarian orbits are suggested, each exploiting a form of harmonic excitation. 5 refs
Prospective Ukrainian lunar orbiter mission
Shkuratov, Y.; Litvinenko, L.; Shulga, V.; Yatskiv, Y.; Kislyuk, V.
Ukraine has launch vehicles that are able to deliver about 300 kg to the lunar orbit. Future Ukrainian lunar program may propose a polar orbiter. This orbiter should fill principal information gaps in our knowledge about the Moon after Clementine and Lunar Prospector missions and the future missions, like Smart-1, Lunar-A, and Selene. We consider that this can be provided by radar studies of the Moon with supporting optical polarimetric observations from lunar polar orbit. These experiments allow one to better understand global structure of the lunar surface in a wide range of scales, from microns to kilometers. We propose three instruments for the prospective lunar orbiter. They are: a synthetic aperture imaging radar (SAR), ground-penetrating radar (GPR), and imaging polarimeter (IP). The main purpose of SAR is to study with high resolution (50 m) the permanently shadowed sites in the lunar polar regions. These sites are cold traps for volatiles, and have a potential of resource utilization. Possible presence of water ice in the regolith in the sites makes them interesting for permanent manned bases on the Moon. Radar imaging and mapping of other interesting regions could be also planned. Multi-frequencies multi-polarization soun d ing of the lunar surface with GPR can provide information about internal structure of the lunar surface from meters to several hundred meters deep. GPR can be used for measuring the megaregolith layer properties, detection of cryptomaria, and studies of internal structure of the largest craters. IP will be a CCD camera with an additional suite of polarizers. Modest spatial resolution (100 m) should provide a total coverage or a large portion of the lunar surface in oblique viewing basically at large phase angles. Polarization degree at large (>90°) phase angles bears information about characteristic size of the regolith particles. Additional radiophysical experiments are considered with the use of the SAR system, e.g., bistatic radar
Quark Orbital Angular Momentum
Directory of Open Access Journals (Sweden)
Burkardt Matthias
2015-01-01
Full Text Available Definitions of orbital angular momentum based on Wigner distributions are used as a framework to discuss the connection between the Ji definition of the quark orbital angular momentum and that of Jaffe and Manohar. We find that the difference between these two definitions can be interpreted as the change in the quark orbital angular momentum as it leaves the target in a DIS experiment. The mechanism responsible for that change is similar to the mechanism that causes transverse single-spin asymmetries in semi-inclusive deep-inelastic scattering.
International Nuclear Information System (INIS)
Boschi Oyhenart, J.; Tenyi, A.; Boschi Pau, J.
2002-01-01
Orbital varices are venous malformations produced by an abnormal dilatation of one or more orbital veins, probably associated with congenital weakness of the vascular wall. They are rare lesions, usually occurring in young patients, that produce intermittent proptosis related to the increase in the systemic venous pressure. The presence of hemorrhage or thrombosis is associated with rapid development of proptosis, pain and decreased ocular motility. We report the cases of two adult patients with orbital varices complicated by thrombosis in whom the diagnosis was based on computed tomography. The ultrasound and magnetic resonance findings are also discussed. (Author) 16 refs
Aiyub, Shereen; Chan, Wengonn; Szetu, John; Sullivan, Laurence J; Pater, John; Cooper, Peter; Selva, Dinesh
2013-12-01
We present a case of mature congenital orbital teratoma managed with lid-sparing exenteration and dermis fat graft. This is a case report on the management of congenital orbital teratoma. A full-term baby was born in Fiji with prolapsed right globe which was surrounded by a nonpulsatile, cystic mass. Clinical and imaging features were consistent with congenital orbital teratoma. Due to limited surgical expertise, the patient was transferred to Adelaide, Australia for further management. The patient underwent a lid-sparing exenteration with frozen section control of the apical margin. A dermis fat graft from the groin was placed beneath the lid skin to provide volume. Histopathology revealed mature tissues from each of the three germ cell layers which confirmed the diagnosis of mature teratoma. We describe the successful use of demis fat graft in socket reconstruction following lid-sparing exenteration for congenital orbital teratoma.
Directory of Open Access Journals (Sweden)
Shereen Aiyub
2013-01-01
Full Text Available We present a case of mature congenital orbital teratoma managed with lid-sparing exenteration and dermis fat graft. This is a case report on the management of congenital orbital teratoma. A full-term baby was born in Fiji with prolapsed right globe which was surrounded by a nonpulsatile, cystic mass. Clinical and imaging features were consistent with congenital orbital teratoma. Due to limited surgical expertise, the patient was transferred to Adelaide, Australia for further management. The patient underwent a lid-sparing exenteration with frozen section control of the apical margin. A dermis fat graft from the groin was placed beneath the lid skin to provide volume. Histopathology revealed mature tissues from each of the three germ cell layers which confirmed the diagnosis of mature teratoma. We describe the successful use of demis fat graft in socket reconstruction following lid-sparing exenteration for congenital orbital teratoma.
Chanel, M; Rumolo, G; Tomás, R; CERN. Geneva. AB Department
2008-01-01
ï»¿At the end of the 2007 run, orbit measurements were carried out in the 4 rings of the PS Booster (PSB) for different working points and beam energies. The aim of these measurements was to provide the necessary input data for a PSB realignment campaign during the 2007/2008 shutdown. Currently, only very few corrector magnets can be operated reliably in the PSB; therefore the orbit correction has to be achieved by displacing (horizontally and vertically) and/or tilting some of the defocusing quadrupoles (QDs). In this report we first describe the orbit measurements, followed by a detailed explanation of the orbit correction strategy. Results and conclusions are presented in the last section.
Orbit effects on impurity transport in a rotating tokamak plasma
International Nuclear Information System (INIS)
Wong, K.L.; Cheng, C.Z.
1988-05-01
Particle orbits in a rotating tokamak plasma are calculated from the equation of motion in the frame that rotates with the plasma. It is found that heavy particles in a rotating plasma can drift away from magnetic surfaces significantly faster with a higher bounce frequency, resulting in a diffusion coefficient much larger than that for a stationary plasma. Particle orbits near the surface of a rotating tokamak are also analyzed. Orbit effects indicate that more impurities can penetrate into a plasma rotating with counter-beam injection. Particle simulation is carried out with realistic experimental parameters and the results are in qualitative agreement with some experimental observations in the Tokamak Fusion Test Reactor (TFTR). 19 refs., 15 figs
Directory of Open Access Journals (Sweden)
Anatoliy Klimyk
2007-02-01
Full Text Available In the paper, properties of antisymmetric orbit functions are reviewed and further developed. Antisymmetric orbit functions on the Euclidean space $E_n$ are antisymmetrized exponential functions. Antisymmetrization is fulfilled by a Weyl group, corresponding to a Coxeter-Dynkin diagram. Properties of such functions are described. These functions are closely related to irreducible characters of a compact semisimple Lie group $G$ of rank $n$. Up to a sign, values of antisymmetric orbit functions are repeated on copies of the fundamental domain $F$ of the affine Weyl group (determined by the initial Weyl group in the entire Euclidean space $E_n$. Antisymmetric orbit functions are solutions of the corresponding Laplace equation in $E_n$, vanishing on the boundary of the fundamental domain $F$. Antisymmetric orbit functions determine a so-called antisymmetrized Fourier transform which is closely related to expansions of central functions in characters of irreducible representations of the group $G$. They also determine a transform on a finite set of points of $F$ (the discrete antisymmetric orbit function transform. Symmetric and antisymmetric multivariate exponential, sine and cosine discrete transforms are given.
International Nuclear Information System (INIS)
Anon.
1991-01-01
Critically aligned experiments are sensitive to small changes in the electron beam orbit. At the NSLS storage rings, the electron beam and photon beam motions have been monitored over the past several years. In the survey conducted in 1986 by the NSLS Users Executive Committee, experimenters requested the vertical beam position variation and the vertical angle variation, within a given fill, remain within 10 μm and 10 μr, respectively. This requires improvement in the beam stability by about one order of magnitude. At the NSLS and SSRL storage rings, the beam that is originally centered on the position monitor by a dc orbit correction is observed to have two kinds of motion: a dc drift over a storage period of several hours and a beam bounce about its nominal position. These motions are a result of the equilibrium orbit not being held perfectly stable due to time-varying errors introduced into the magnetic guide field by power supplies, mechanical vibration of the magnets, cooling water temperature variations, etc. The approach to orbit stabilization includes (1) identifying and suppressing as many noise sources on the machine as possible, (2) correcting the beam position globally (see Section 6) by controlling a number of correctors around the circumference of the machine, and (3) correcting the beam position and angle at a given source location by position feedback using local detectors and local orbit bumps. The third approach, called Local Orbit Feedback will be discussed in this section
Plasma balance equations based on orbit theory
International Nuclear Information System (INIS)
Lehnert, B.
1982-01-01
A set of plasma balance equations is proposed which is based on orbit theory and the particle distribution function, to provide means for theoretical analysis of a number of finite Larmor radius (FLR) phenomena without use of the Vlasov equation. Several important FLR effects originate from the inhomogeneity of an electric field in the plasma. The exact solution of a simple case shows that this inhomogeneity introduces fundamental changes in the physics of the particle motion. Thus, the periodic Larmor motion (gyration) is shifted in frequency and becomes elliptically polarized. Further, the non-periodic guiding-centre drift obtains additional components, part of which are accelerated such as to make the drift orbits intersect the equipotential surfaces of a static electric field. An attempt is finally made to classify the FLR effects, also with the purpose of identifying phenomena which have so far not been investigated. (author)
Low energy plasma observations at synchronous orbit
International Nuclear Information System (INIS)
Reasoner, D.L.; Lennartsson, W.
1977-08-01
The University of California at San Diego Auroral Particles Experiment on the ATS-6 Satellite in synchronous orbit has detected a low-energy plasma population which is separate and distinct from both the ring current and plasma sheet populations. These observations suggest that this plasma is the outer zone of the plasmasphere. During magnetically active periods, this low energy plasma is often observed flowing sunward. In the dusk sector, enhanced plasma flow is often observed for 1-2 hours prior to the onset of a substorm-associated particle injection. (author)
Relativistic spin-orbit interactions of photons and electrons
Smirnova, D. A.; Travin, V. M.; Bliokh, K. Y.; Nori, F.
2018-04-01
Laboratory optics, typically dealing with monochromatic light beams in a single reference frame, exhibits numerous spin-orbit interaction phenomena due to the coupling between the spin and orbital degrees of freedom of light. Similar phenomena appear for electrons and other spinning particles. Here we examine transformations of paraxial photon and relativistic-electron states carrying the spin and orbital angular momenta (AM) under the Lorentz boosts between different reference frames. We show that transverse boosts inevitably produce a rather nontrivial conversion from spin to orbital AM. The converted part is then separated between the intrinsic (vortex) and extrinsic (transverse shift or Hall effect) contributions. Although the spin, intrinsic-orbital, and extrinsic-orbital parts all point in different directions, such complex behavior is necessary for the proper Lorentz transformation of the total AM of the particle. Relativistic spin-orbit interactions can be important in scattering processes involving photons, electrons, and other relativistic spinning particles, as well as when studying light emitted by fast-moving bodies.
The effect of J2 on equatorial and halo orbits around a magnetic planet
International Nuclear Information System (INIS)
Inarrea, Manuel; Lanchares, Victor; Palacian, Jesus F.; Pascual, Ana I.; Pablo Salas, J.; Yanguas, Patricia
2009-01-01
We calculate equatorial and halo orbits around a non-spherical (both oblate and prolate) magnetic planet. It is known that circular equatorial and halo orbits exist for a dust grain orbiting a spherical magnetic planet. However, the frequency of the orbit is constrained by the charge-mass ratio of the particle. If the non-sphericity of the planet is taken into account this constraint is modified or, in some cases, it disappears.
The effect of J{sub 2} on equatorial and halo orbits around a magnetic planet
Energy Technology Data Exchange (ETDEWEB)
Inarrea, Manuel [Universidad de la Rioja, Area de Fisica, 26006 Logrono (Spain); Lanchares, Victor [Dpto. de Matematicas y Computacion, CIEMUR: Centro de Investigacion en Informatica, Estadistica y Matematicas, Universidad de la Rioja, 26004 Logrono (Spain)], E-mail: vlancha@unirioja.es; Palacian, Jesus F. [Universidad Publica de Navarra, Departamento de Ingenieria Matematica e Informatica, 31006 Pamplona (Spain); Pascual, Ana I. [Dpto. de Matematicas y Computacion, CIEMUR: Centro de Investigacion en Informatica, Estadistica y Matematicas, Universidad de la Rioja, 26004 Logrono (Spain); Pablo Salas, J. [Universidad de la Rioja, Area de Fisica, 26006 Logrono (Spain); Yanguas, Patricia [Universidad Publica de Navarra, Departamento de Ingenieria Matematica e Informatica, 31006 Pamplona (Spain)
2009-10-15
We calculate equatorial and halo orbits around a non-spherical (both oblate and prolate) magnetic planet. It is known that circular equatorial and halo orbits exist for a dust grain orbiting a spherical magnetic planet. However, the frequency of the orbit is constrained by the charge-mass ratio of the particle. If the non-sphericity of the planet is taken into account this constraint is modified or, in some cases, it disappears.
Directory of Open Access Journals (Sweden)
Jiri Patera
2008-01-01
Full Text Available We review and further develop the theory of $E$-orbit functions. They are functions on the Euclidean space $E_n$ obtained from the multivariate exponential function by symmetrization by means of an even part $W_{e}$ of a Weyl group $W$, corresponding to a Coxeter-Dynkin diagram. Properties of such functions are described. They are closely related to symmetric and antisymmetric orbit functions which are received from exponential functions by symmetrization and antisymmetrization procedure by means of a Weyl group $W$. The $E$-orbit functions, determined by integral parameters, are invariant withrespect to even part $W^{aff}_{e}$ of the affine Weyl group corresponding to $W$. The $E$-orbit functions determine a symmetrized Fourier transform, where these functions serve as a kernel of the transform. They also determine a transform on a finite set of points of the fundamental domain $F^{e}$ of the group $W^{aff}_{e}$ (the discrete $E$-orbit function transform.
Antonella Del Rosso
2014-01-01
These devices are designed to provide a current pulse of 5000 Amps which will in turn generate a fast magnetic pulse that steers the incoming beam into the LHC. Today, the comprehensive upgrade of the LHC injection kicker system is entering its final stages. The upgraded system will ensure the LHC can be refilled without needing to wait for the kicker magnets to cool, thus enhancing the performance of the whole accelerator. An upgraded kicker magnet in its vacuum tank, with an upgraded beam screen. The LHC is equipped with two kicker systems installed at the injection points (near points 2 and 8, see schematic diagram) where the particle beams coming from the SPS are injected into the accelerator’s orbit. Each system comprises four magnets and four pulse generators in which the field rises to 0.12 Tesla in less than 900 nanoseconds and for a duration of approximately 8 microseconds. Although the injection kickers only pulse 12 times to fill the LHC up with beam, the LHC beam circ...
Basanta, I; Sevillano, C; Álvarez, M D
2015-09-01
A case is presented of an 85 year-old Caucasian female with lymphoma that recurred in the orbit (secondary ocular adnexal lymphoma). The orbital tumour was a diffuse large B-cell lymphoma according to the REAL classification (Revised European-American Lymphoma Classification). Orbital lymphomas are predominantly B-cell proliferations of a variety of histological types, and most are low-grade tumours. Patients are usually middle-aged or elderly, and it is slightly more common in women. A palpable mass, proptosis and blepharoptosis are the most common signs of presentation. Copyright © 2011 Sociedad Española de Oftalmología. Published by Elsevier España, S.L.U. All rights reserved.
Large orbit neoclassical transport
International Nuclear Information System (INIS)
Lin, Z.; Tang, W.M.; Lee, W.W.
1997-01-01
Neoclassical transport in the presence of large ion orbits is investigated. The study is motivated by the recent experimental results that ion thermal transport levels in enhanced confinement tokamak plasmas fall below the open-quotes irreducible minimum levelclose quotes predicted by standard neoclassical theory. This apparent contradiction is resolved in the present analysis by relaxing the basic neoclassical assumption that the ions orbital excursions are much smaller than the local toroidal minor radius and the equilibrium scale lengths of the system. Analytical and simulation results are in agreement with trends from experiments. The development of a general formalism for neoclassical transport theory with finite orbit width is also discussed. copyright 1997 American Institute of Physics
International Nuclear Information System (INIS)
Hoeschen, W.
2003-01-01
The TIG (Tungsten-inert gas) orbital welding technique is applied in all areas of pipe welding. The process is mainly used for austenitic and ferritic materials but also for materials like aluminium, nickel, and titanium alloys are commonly welded according to this technique. Thin-walled as well as thick-walled pipes are welded economically. The application of orbital welding is of particular interest in the area of maintenance of thick-walled pipes that is described in this article. (orig.) [de
Directory of Open Access Journals (Sweden)
Kyu-Hong Choi
1990-06-01
Full Text Available The osculating orbital elements include the mean, secular, long period, and short period terms. The iterative algorithm used for conversion of osculating orbital elements to mean orbital elements is described. The mean orbital elements of Wc, Ws, and L are obtained.
Energy Technology Data Exchange (ETDEWEB)
Bianchi, L. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires
1969-07-01
A table of charged particle energies versus magnetic field strength x orbit radius (B{sub {rho}}) is presented. Particles p, d, t, {sup 3}He{sup ++}, {sup 4}He{sup +}, {sup 4}He{sup ++}, {sup 6}Li{sup +}, {sup 6}Li{sup ++}, {sup 6}Li{sup +++}, {sup 7}Li{sup +}, {sup 7}Li{sup ++}, {sup 7}Li{sup +++}. Values of B{sub {rho}}: 100 to 1200 kG.cm by steps of 0.5 kG.cm. Values of energies are given in keV. (author) [French] Nous presentons une table des energies de protons, deutons, tritons, {sup 3}He{sup ++}, {sup 4}He{sup +}, {sup 4}He{sup ++}, {sup 6}Li{sup +}, {sup 6}Li{sup ++}, {sup 6}Li{sup +++}, {sup 7}Li{sup +}, {sup 7}Li{sup ++}, {sup 7}Li{sup +++} en fonction de leur rigidite magnetique (B{sub {rho}}). Les valeurs de B{sub {rho}} sont comprises entre 100 et 1200 kG.cm par pas de 0.5 kG.cm. Les valeurs des energies sont donnees en keV. (auteur)
Accelerated simulation of near-Earth-orbit polymer degradation
Laue, Eric
1992-01-01
There is a need to simulate the near-Earth-orbit environmental conditions, and it is useful to be able to monitor the changes in physical properties of spacecraft materials. Two different methods for simulating the vacuum-ultraviolet (VUV) and soft X-ray near-Earth-orbit flux are presented. Also, methods for monitoring the changes in optical ultraviolet transmission and mass loss are presented. The results of exposures to VUV photons and charged particles on these materials are discussed.
Nuclear spin-orbit splitting from an intermediate Δ excitation
International Nuclear Information System (INIS)
Ohta, K.; Terasawa, T.; Tohyama, M.
1980-01-01
The strength of the single particle spin-orbit potential is calculated from the two pion exchange box diagrams involving an intermediate Δ(1232) resonance excitation by taking account of the exclusion principle for the intermediate nucleon states. The effect of the rho meson is also considered. The predicted strength is found to account for a substantial part of the empirical spin-orbit splittings
International Nuclear Information System (INIS)
Harcourt, R.D.
1987-01-01
Bohr orbit theory is used to calculate energies for the 1S, 2P, 3D, 4F and 5G states of the helium muonic atom, when the muon is excited. These energies are close to those which have been calculated variationally by Huang (1977, Phys. Rev. A 15 1832-8). (author)
Meteoroid Orbits from Observations
Campbell-Brown, Margaret
2018-04-01
Millions of orbits of meteoroids have been measured over the last few decades, and they comprise the largest sample of orbits of solar system bodies which exists. The orbits of these objects can shed light on the distribution and evolution of comets and asteroids in near-Earth space (e.g. Neslusan et al. 2016). If orbits can be measured at sufficiently high resolution, individual meteoroids can be traced back to their parent bodies and, in principle, even to their ejection time (Rudawska et al. 2012). Orbits can be measured with multi-station optical observations or with radar observations.The most fundamental measured quantities are the speed of the meteor and the two angles of the radiant, or point in the sky from which the meteor appears to come. There are many methods used to determine these from observations, but not all produce the most accurate results (Egal et al. 2017). These three measured quantities, along with the time and location of the observation, are sufficient to obtain an orbit (see, e.g., Clark & Wiegert 2011), but the measurements must be corrected for the deceleration of the meteoroid in the atmosphere before it was detected, the rotation of the Earth, and the gravitational attraction of the Earth (including higher order moments if great precision is necessary).Once meteor orbits have been determined, studies of the age and origin of meteor showers (Bruzzone et al., 2015), the parent bodies of sporadic sources (Pokorny et al. 2014), and the dynamics of the meteoroid complex as a whole can be constrained.Bruzzone, J. S., Brown, P., Weryk, R., Campbell-Brown, M., 2015. MNRAS 446, 1625.Clark, D., Wiegert, P., 2011. M&PS 46, 1217.Egal, A., Gural, P., Vaubaillon, J., Colas, F., Thuillot, W., 2017. Icarus 294, 43.Neslusan, L., Vaubaillon, J., Hajdukova, M., 2016. A&A 589, id.A100.Pokorny, P., Vokrouhlicky, D., Nesvorny, D., Campbell-Brown, M., Brown, P., 2014. ApJ 789, id.25.Rudawska, R., Vaubaillon, J., Atreya, P., 2012. A&A 541, id.A2
Analytic robust stability analysis of SVD orbit feedback
Pfingstner, Jürgen
2012-01-01
Orbit feedback controllers are indispensable for the operation of modern particle accelerators. Many such controllers are based on the decoupling of the inputs and outputs of the system to be controlled with the help of the singular value decomposition (SVD controller). It is crucial to verify the stability of SVD controllers, also in the presence of mismatches between the used accelerator model and the real machine (robust stability problem). In this paper, analytical criteria for guaranteed stability margins of SVD orbit feedback systems for three different types of model mismatches are presented: scaling errors of actuators and BPMs (beam position monitors) and additive errors of the orbit response matrix. For the derivation of these criteria, techniques from robust control theory have been used, e.g the small gain theorem. The obtained criteria can be easily applied directly to other SVD orbit feedback systems. As an example, the criteria were applied to the orbit feedback system of the Compact Linear ...
Mercury Orbiter: Report of the Science Working Team
Belcher, John W.; Slavin, James A.; Armstrong, Thomas P.; Farquhar, Robert W.; Akasofu, Syun I.; Baker, Daniel N.; Cattell, Cynthia A.; Cheng, Andrew F.; Chupp, Edward L.; Clark, Pamela E.
1991-01-01
The results are presented of the Mercury Orbiter Science Working Team which held three workshops in 1988 to 1989 under the auspices of the Space Physics and Planetary Exploration Divisions of NASA Headquarters. Spacecraft engineering and mission design studies at the Jet Propulsion Lab were conducted in parallel with this effort and are detailed elsewhere. The findings of the engineering study, summarized herein, indicate that spin stabilized spacecraft carrying comprehensive particles and fields experiments and key planetology instruments in high elliptical orbits can survive and function in Mercury orbit without costly sun shields and active cooling systems.
Mechanical systems with closed orbits on manifolds of revolution
International Nuclear Information System (INIS)
Kudryavtseva, E A; Fedoseev, D A
2015-01-01
We study natural mechanical systems describing the motion of a particle on a two-dimensional Riemannian manifold of revolution in the field of a central smooth potential. We obtain a classification of Riemannian manifolds of revolution and central potentials on them that have the strong Bertrand property: any nonsingular (that is, not contained in a meridian) orbit is closed. We also obtain a classification of manifolds of revolution and central potentials on them that have the 'stable' Bertrand property: every parallel is an 'almost stable' circular orbit, and any nonsingular bounded orbit is closed. Bibliography: 14 titles
Spin-orbit scattering in superconducting nanoparticles
Energy Technology Data Exchange (ETDEWEB)
Alhassid, Y. [Center for Theoretical Physics, Sloane Physics Laboratory, Yale University, New Haven, Connecticut, 06520 (United States); Nesterov, K.N. [Department of Physics, University of Wisconsin-Madison, Madison, Wisconsin, 53706 (United States)
2017-06-15
We review interaction effects in chaotic metallic nanoparticles. Their single-particle Hamiltonian is described by the proper random-matrix ensemble while the dominant interaction terms are invariants under a change of the single-particle basis. In the absence of spin-orbit scattering, the nontrivial invariants consist of a pairing interaction, which leads to superconductivity in the bulk, and a ferromagnetic exchange interaction. Spin-orbit scattering breaks spin-rotation invariance and when it is sufficiently strong, the only dominant nontrivial interaction is the pairing interaction. We discuss how the magnetic response of discrete energy levels of the nanoparticle (which can be measured in single-electron tunneling spectroscopy experiments) is affected by such pairing correlations and how it can provide a signature of pairing correlations. We also consider the spin susceptibility of the nanoparticle and discuss how spin-orbit scattering changes the signatures of pairing correlations in this observable. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)
Conformal description of spinning particles
International Nuclear Information System (INIS)
Todorov, I.T.
1986-01-01
This book is an introduction to the application of the conformal group to quantum field theory of particles with spin. After an introduction to the twistor representations of the conformal group of a conformally flat space-time and twistor flag manifolds with Su(2,2) orbits the classical phase space of conformal spinning particles is described. Thereafter the twistor description of classical zero mass fields is considered together with the quantization. (HSI)
Orbit width scaling of TAE instability growth rate
International Nuclear Information System (INIS)
Wong, H.V.; Berk, H.L.; Breizman, B.N.
1995-07-01
The growth rate of Toroidal Alfven Eigenmodes (TAE) driven unstable by resonant coupling of energetic charged particles is evaluated in the ballooning limit over a wide range of parameters. All damping effects are ignored. Variations in orbit width, aspect ratio, and the ratio of alfven velocity to energetic particle birth velocity, are explored. The relative contribution of passing and trapped particles, and finite Larmor radius effects, are also examined. The phase space location of resonant particles with interact strongly with the modes is described. The accuracy of the analytic results with respect to growth rate magnitude and parametric dependence is investigated by comparison with numerical results
Orbit width scaling of TAE instability growth rate
International Nuclear Information System (INIS)
Wong, H.V.; Berk, H.L.; Breizman, B.N.
1995-01-01
The growth rate of toroidal Alfven eigenmodes (TAEs) driven unstable by resonant coupling of energetic charged particles is evaluated in the 'ballooning' limit over a wide range of parameters. All damping effects are ignored. Variations in orbit width, aspect ratio and the ratio of Alfven velocity to energetic particle 'birth' velocity are explored. The relative contribution of passing and trapped particles, and finite Larmor radius effects, are also examined. The phase space location of resonant particles that interact strongly with the modes is described. The accuracy of the analytic results with respect to growth rate magnitude and parametric dependence is investigated by comparison with numerical results. (author). 16 refs, 8 figs
Local orbitals by minimizing powers of the orbital variance
DEFF Research Database (Denmark)
Jansik, Branislav; Høst, Stinne; Kristensen, Kasper
2011-01-01
's correlation consistent basis sets, it is seen that for larger penalties, the virtual orbitals become more local than the occupied ones. We also show that the local virtual HF orbitals are significantly more local than the redundant projected atomic orbitals, which often have been used to span the virtual...
Correlated nucleon motion and fractional occupation of orbitals in sup 2 sup 0 sup 8 Pb
De Witt-Huberts, P K A
1999-01-01
The low-energy states of nearly closed-shell nuclei can be interpreted as having quasi-particles in single-particle orbitals. The difference between physical particle and quasi particle, resulting from correlations, is quantified by the quasi-hole strength z that represents the probability of the quasi-particle being a physical particle. We present empirical evidence from quasi-free proton knockout with electrons for a substantially quenched z-value for the 3s orbital in sup 2 sup 0 sup 8 Pb. With z values derived from (e,e'p) and elastic electron-scattering data the absolute occupation for the 3s orbital in sup 2 sup 0 sup 8 Pb is derived. Results from both theory and experiment imply that only approx 2/3 of the nucleons act as independent particles bound in an average potential.
Correlated nucleon motion and fractional occupation of orbitals in 208Pb
International Nuclear Information System (INIS)
De Witt Huberts, Peter K.A.
1999-01-01
The low-energy states of nearly closed-shell nuclei can be interpreted as having quasi-particles in single-particle orbitals. The difference between physical particle and quasi particle, resulting from correlations, is quantified by the quasi-hole strength z that represents the probability of the quasi-particle being a physical particle. We present empirical evidence from quasi-free proton knockout with electrons for a substantially quenched z-value for the 3s orbital in 208 Pb. With z values derived from (e,e'p) and elastic electron-scattering data the absolute occupation for the 3s orbital in 208 Pb is derived. Results from both theory and experiment imply that only ∼ 2/3 of the nucleons act as independent particles bound in an average potential
Energy Technology Data Exchange (ETDEWEB)
Gouttefangeas, M; Katz, A; Rastoix, G [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires
1963-07-01
In this report is briefly described the beam-kicker system of the synchrotron Saturne. An analysis of its operation based on the sampling method is given, as well as two methods for computing toe magnetic field produced by a set of endless conductors in the neighbourhood of a conducting shield where eddy currents are circulating. The first method leads to the resolution of a bi-dimensional Laplace equation with first kind boundary conditions (Dirichlet problem); the second one translates to electromagnetism the electrical images method currently used in electrostatics and yields the magnetic field as the sum of a triple series expansion in the general case of a set of conductors located in a parallelepipedal box. Finally are given the results obtained in computing on IBM 7090 the perturbation of the particle motion due to the beam-kicker. These results are compared with the experimental data. (authors) [French] Ce rapport decrit brievement le dispositif percuteur de faisceau mis en place sur le synchrotron Saturne. On y trouvera une analyse de se fonctionnement a partir de la theorie des echantillonnages. On indique egalment deux methodes de calcul du champ magnetique produit par un system de conducteurs indefinis en presence d'un blindage conducteur parcouru par des courants de Foucault: la premiere se ramene a la resolution d'une equation de Laplace a deux dimensions avec des conditions aux limites de premiere espece (probleme de Dirichlet), la seconde transpose en electromagnetisme la methode des images electriques classique en electrostatique et permet d'exprimer le champ magnetique sous la forme de la somme d'une serie triple dans le cas general d'un systeme de conducteurs contenus dans un blindage parallelepipedique. Pour terminer, on mentionne les resultats du calcul numerique de la perturbation de la trajectoire des particules sous l'effet du percuteur et on compare ces resultats aux resultats experimentaux. (auteurs)
Orbital debris: a technical assessment
National Research Council Canada - National Science Library
Committee on Space Debris, National Research Council
..., and other debris created as a byproduct of space operations. Orbital Debris examines the methods we can use to characterize orbital debris, estimates the magnitude of the debris population, and assesses the hazard that this population poses to spacecraft...
Orbiter OMS and RCS technology
Boudreaux, R. A.
1982-01-01
Orbiter Orbital Maneuver Subsystem (OMS) and Reaction Control Subsystem (RCS) tankage has proved to be highly successful in shuttle flights on-orbit propellant transfer tests were done. Tank qualification tests along with flight demonstrations were carried out future uses of storable propellants are cited.
International Nuclear Information System (INIS)
Kutschera, W.
1984-01-01
The use of Accelerator Mass Spectrometry (AMS) to search for hypothetical particles and known particles of rare processes is discussed. The hypothetical particles considered include fractionally charged particles, anomalously heavy isotopes, and superheavy elements. The known particles produced in rare processes discussed include doubly-charged negative ions, counting neutrino-produced atoms in detectors for solar neutrino detection, and the spontaneous emission of 14 C from 223 Ra. 35 references
Orbit Propagation and Determination of Low Earth Orbit Satellites
Directory of Open Access Journals (Sweden)
Ho-Nien Shou
2014-01-01
Full Text Available This paper represents orbit propagation and determination of low Earth orbit (LEO satellites. Satellite global positioning system (GPS configured receiver provides position and velocity measures by navigating filter to get the coordinates of the orbit propagation (OP. The main contradictions in real-time orbit which is determined by the problem are orbit positioning accuracy and the amount of calculating two indicators. This paper is dedicated to solving the problem of tradeoffs. To plan to use a nonlinear filtering method for immediate orbit tasks requires more precise satellite orbit state parameters in a short time. Although the traditional extended Kalman filter (EKF method is widely used, its linear approximation of the drawbacks in dealing with nonlinear problems was especially evident, without compromising Kalman filter (unscented Kalman Filter, UKF. As a new nonlinear estimation method, it is measured at the estimated measurements on more and more applications. This paper will be the first study on UKF microsatellites in LEO orbit in real time, trying to explore the real-time precision orbit determination techniques. Through the preliminary simulation results, they show that, based on orbit mission requirements and conditions using UKF, they can satisfy the positioning accuracy and compute two indicators.
Majorana-Fermi-Segre, E.-L.; Antonoff-Overhauser-Salam, Marvin-Albert-Abdus; Siegel, Edward Carl-Ludwig
2013-03-01
Majorana-fermions, being their own antiparticles, following non-Abelian anyon/semion quantum-statistics: in Zhang et.al.-...-Detwiler et.al.-...``Worlds-in-Collision'': solid-state/condensed-matter - physics spin-orbit - coupled topological-excitations in superconductors and/or superfluids -to- particle-physics neutrinos: ``When `Worlds' Collide'', analysis via Siegel[Schrodinger Centenary Symp., Imperial College, London (1987); in The Copenhagen-Interpretation Fifty-Years After the Como-Lecture, Symp. Fdns. Mod.-Phys., Joensu(1987); Symp. on Fractals, MRS Fall-Mtg., Boston(1989)-5-papers!!!] ``complex quantum-statistics in fractal-dimensions'', which explains hidden-dark-matter(HDM) IN Siegel ``Sephirot'' scenario for The Creation, uses Takagi[Prog.Theo.Phys. Suppl.88,1(86)]-Ooguri[PR D33,357(85)] - Picard-Lefschetz-Arnol'd-Vassil'ev[``Principia Read After 300 Years'', Not.AMS(1989); quantum-theory caveats comment-letters(1990); Applied Picard-Lefschetz Theory, AMS(2006)] - theorem quantum-statistics, which via Euler- formula becomes which via de Moivre- -formula further becomes which on unit-circle is only real for only, i.e, for, versus complex with imaginary-damping denominator for, i.e, for, such that Fermi-Dirac quantum-statistics for
Orbital magnetism and dynamics in alkali metal clusters
International Nuclear Information System (INIS)
Nesterenko, V.O.; Kleinig, W.; Souza Cruz, FF. de; Marinelli, J.R.
2000-01-01
Two remarkable orbital magnetic resonances, M1 scissor mode and M2 twist mode, are predicted in deformed and spherical metal clusters, respectively. We show that these resonances provide a valuable information about many cluster properties (quadrupole deformation, magnetic susceptibility, single-particle spectrum, etc.)
Fluctuation theorems and orbital magnetism in nonequilibrium state
Indian Academy of Sciences (India)
We study Langevin dynamics of a driven charged particle in the presence as well as in the absence of magnetic field. We discuss the validity of various work fluctuation theorems using different model potentials and external drives. We also show that one can generate an orbital magnetic moment in a nonequilibrium state ...
Nonlinear realizations, the orbit method and Kohn's theorem
Andrzejewski, K.; Gonera, J.; Kosinski, P.
2012-01-01
The orbit method is used to describe the centre of mass motion of the system of particles with fixed charge to mass ratio moving in homogeneous magnetic field and confined by harmonic potential. The nonlinear action of symmetry group on phase space is identified and compared with the one obtained with the help of Eisenhart lift.
Orbital motions as gradiometers for post-Newtonian tidal effects
Energy Technology Data Exchange (ETDEWEB)
Iorio, Lorenzo, E-mail: lorenzo.iorio@libero.it [Ministero dell' Istruzione, dell' Università e della Ricerca, Istruzione, Bari (Italy)
2014-08-14
The direct long-term changes occurring in the orbital dynamics of a local gravitationally bound binary system S due to the post-Newtonian tidal acceleration caused by an external massive source are investigated. A class of systems made of a test particle m rapidly orbiting with orbital frequency n{sub b} an astronomical body of mass M which, in turn, slowly revolves around a distant object of mass M′ with orbital frequency n{sub b}′ « n{sub b} is considered. The characteristic frequencies of the non-Keplerian orbital variations of m and of M itself are assumed to be negligible with respect to both n{sub b} and n{sub b}′. General expressions for the resulting Newtonian and post-Newtonian tidal orbital shifts of m are obtained. The future missions BepiColombo and JUICE to Mercury and Ganymede, respectively, are considered in view of a possible detection. The largest effects, of the order of ≈ 0.1-0.5 milliarcseconds per year (mas yr{sup −1}), occur for the Ganymede orbiter of the JUICE mission. Although future improvements in spacecraft tracking and orbit determination might, perhaps, reach the required sensitivity, the systematic bias represented by the other known orbital perturbations of both Newtonian and post-Newtonian origin would be overwhelming. The realization of a dedicated artificial mini-planetary system to be carried onboard and Earth-orbiting spacecraft is considered as well. Post-Newtonian tidal precessions as large as ≈ 1−10{sup 2} mas yr{sup −1} could be obtained, but the quite larger Newtonian tidal effects would be a major source of systematic bias because of the present-day percent uncertainty in the product of the Earth's mass times the Newtonian gravitational parameter.
The Kirillov picture for the Wigner particle
Gracia-Bondía, J. M.; Lizzi, F.; Várilly, J. C.; Vitale, P.
2018-06-01
We discuss the Kirillov method for massless Wigner particles, usually (mis)named ‘continuous spin’ or ‘infinite spin’ particles. These appear in Wigner’s classification of the unitary representations of the Poincaré group, labelled by elements of the enveloping algebra of the Poincaré Lie algebra. Now, the coadjoint orbit procedure introduced by Kirillov is a prelude to quantization. Here we exhibit for those particles the classical Casimir functions on phase space, in parallel to quantum representation theory. A good set of position coordinates are identified on the coadjoint orbits of the Wigner particles; the stabilizer subgroups and the symplectic structures of these orbits are also described. In memory of E C G Sudarshan.
International Nuclear Information System (INIS)
Li, Manman; Yan, Shaohui; Yao, Baoli; Liang, Yansheng; Lei, Ming; Yang, Yanlong
2016-01-01
Optical vortex beams carry optical orbital angular momentum (OAM) and can induce an orbital motion of trapped particles in optical trapping. We show that the state of polarization (SOP) of vortex beams will affect the details of this optically induced orbital motion to some extent. Numerical results demonstrate that focusing the vortex beams with circular, radial or azimuthal polarizations can induce a uniform orbital motion on a trapped Rayleigh particle, while in the focal field of the vortex beam with linear polarization the particle experiences a non-uniform orbital motion. Among the formers, the vortex beam with circular polarization induces a maximum optical torque on the particle. Furthermore, by varying the topological charge of the vortex beams, the vortex beam with circular polarization gives rise to an optimum torque superior to those given by the other three vortex beams. These facts suggest that the circularly polarized vortex beam is more suitable for rotating particles. - Highlights: • States of polarization of vortex beams affect the optically induced orbital motion of particles. • The dependences of the force and orbital torque on the topological charge, the size and the absorptivity of particles were calculated. • Focused vortex beams with circular, radial or azimuthal polarizations induce a uniform orbital motion on particles. • Particles experience a non-uniform orbital motion in the focused linearly polarized vortex beam. • The circularly polarized vortex beam is a superior candidate for rotating particles.
A Typical Presentation of Orbital Pseudotumor Mimicking Orbital Cellulitis
Directory of Open Access Journals (Sweden)
J. Ayatollahi
2013-10-01
Full Text Available Introduction: Orbital pseudotumor, also known as idiopathic orbital inflammatory syndrome (IOIS, is a benign, non- infective inflammatory condition of the orbit without identifiable local or systemic causes. The disease may mimics a variety of pathologic conditions. We pre-sent a case of pseudotumor observed in a patient admitted under the name of orbital celluli-ties. Case Report: A 26-year-old woman reffered to our hospital with the history of left ocular pain and headache 2 days before her visit.. Ophthalmological examination of the patient was normal except for the redness and lid edema, mild chemosis and conjunctival injection. Gen-eral assessment was normal but a low grade fever was observed. She was hospitalized as an orbital cellulitis patient. She was treated with intravenous antibiotics. On the third day , sud-denly diplopia, proptosis in her left eye and ocular pain in her right side appeared. MRI re-vealed bilateral enlargement of extraocular muscles. Diagnosis of orbital pseudotumor was made and the patient was treated with oral steroid.She responded promptly to the treatment. Antibiotics were discontinued and steroid was tapered in one month period under close fol-low up. Conclusion: The clinical features of orbital pseudotumor vary widely . Orbital pseudotumor and orbital cellulitis can occasionally demonstrate overlapping features.. Despite complete physical examination and appropriate imaging, sometimes correct diagnosis of the disease would be difficult (Sci J Hamadan Univ Med Sci 2013; 20 (3:256-259
The Zeeman-split superconductivity with Rashba and Dresselhaus spin-orbit coupling
Zhao, Jingxiang; Yan, Xu; Gu, Qiang
2017-10-01
The superconductivity with Rashba and Dressehlaus spin-orbit coupling and Zeeman effect is investigated. The energy gaps of quasi-particles are carefully calculated. It is shown that the coexistence of two spin-orbit coupling might suppress superconductivity. Moreover, the Zeeman effect favors spin-triplet Cooper pairs.
Orbital preservation in a maxillectomy
Energy Technology Data Exchange (ETDEWEB)
Tanaka, Katsuhiko; Nishikawa, Hitomi; Kumagai, Masahiko; Dosaka, Yoshihiro; Kuroda, Toru; Atago, Yoshihiro; Nishio, Masamichi [Sapporo National Hospital (Japan)
1999-07-01
In the past 9 years, 38 patients of the maxillary cancer were treated by a combination of radiation and surgery. Sixteen patients showed the orbital involvement as confirmed by a CT scan and/or MRI. An orbital excenteration was necessary in 6 patients, due mainly to deep intraorbital invasion, while in 10, the orbital contents were preserved despite the involvement of the orbital capsule. The local rate of the orbital region in the latter patients evaluated at 48 months after the initial surgery was 44%. For the treatment of the recurrence at the orbital capsule. The application of gold grain (Au{sup 198}) thus appeared to be a useful tool for further preserving the eye. (author)
Orbital preservation in a maxillectomy
International Nuclear Information System (INIS)
Tanaka, Katsuhiko; Nishikawa, Hitomi; Kumagai, Masahiko; Dosaka, Yoshihiro; Kuroda, Toru; Atago, Yoshihiro; Nishio, Masamichi
1999-01-01
In the past 9 years, 38 patients of the maxillary cancer were treated by a combination of radiation and surgery. Sixteen patients showed the orbital involvement as confirmed by a CT scan and/or MRI. An orbital excenteration was necessary in 6 patients, due mainly to deep intraorbital invasion, while in 10, the orbital contents were preserved despite the involvement of the orbital capsule. The local rate of the orbital region in the latter patients evaluated at 48 months after the initial surgery was 44%. For the treatment of the recurrence at the orbital capsule. The application of gold grain (Au 198 ) thus appeared to be a useful tool for further preserving the eye. (author)
Polaronic and dressed molecular states in orbital Feshbach resonances
Xu, Junjun; Qi, Ran
2018-04-01
We consider the impurity problem in an orbital Feshbach resonance (OFR), with a single excited clock state | e ↑⟩ atom immersed in a Fermi sea of electronic ground state | g ↓⟩. We calculate the polaron effective mass and quasi-particle residue, as well as the polaron to molecule transition. By including one particle-hole excitation in the molecular state, we find significant correction to the transition point. This transition point moves toward the BCS side for increasing particle densities, which suggests that the corresponding many-body physics is similar to a narrow resonance.
International Nuclear Information System (INIS)
Michelotti, L.
1989-03-01
Unlike the other documents in these proceedings, this paper is neither a scientific nor a technical report. It is, rather, a short personal essay which attempts to describe an Exploratory Orbit Analysis (EOA) environment. Analyzing the behavior of a four or six dimensional nonlinear dynamical system is at least as difficult as analyzing events in high-energy collisions; the consequences of doing it badly, or slowly, would be at least as devastating; and yet the level of effort and expenditure invested in the latter, the very attention paid to it by physicists at large, must be two orders of magnitude greater than that given to the former. It is difficult to choose the model which best explains the behavior of a physical device if one does not first understand the behavior of the available models. The time is ripe for the development of a functioning EOA environment, which I will try to describe in this paper to help us achieve this goal
Energy Technology Data Exchange (ETDEWEB)
Michelotti, L.
1989-03-01
Unlike the other documents in these proceedings, this paper is neither a scientific nor a technical report. It is, rather, a short personal essay which attempts to describe an Exploratory Orbit Analysis (EOA) environment. Analyzing the behavior of a four or six dimensional nonlinear dynamical system is at least as difficult as analyzing events in high-energy collisions; the consequences of doing it badly, or slowly, would be at least as devastating; and yet the level of effort and expenditure invested in the latter, the very attention paid to it by physicists at large, must be two orders of magnitude greater than that given to the former. It is difficult to choose the model which best explains the behavior of a physical device if one does not first understand the behavior of the available models. The time is ripe for the development of a functioning EOA environment, which I will try to describe in this paper to help us achieve this goal.
Directory of Open Access Journals (Sweden)
Deniz Marangoz
2016-10-01
Full Text Available A 29-year-old female patient presented with a painless mass on her upper eyelid medially. She noticed the mass 4 years earlier and it had increased in size over time. She had no diplopia, eyelid swelling, skin lesion overlying the mass, or visual disturbances. On ocular examination, eye movements and funduscopy were normal. The mass was movable and painless with palpation. Magnetic resonance imaging with contrast showed a 12x8x7 mm well-circumscribed cystic lesion with no contrast dye appearance. Surgical removal was performed delicately and no capsular rupture occured. Pathological examination revealed an eccrine hidrocystoma. Our aim is to underline that eccrine hidrocystoma should be included in differential diagnosis of orbital masses.
Cioslowski, Jerzy
2018-04-01
The dependence of the natural amplitudes of the harmonium atom in its ground state on the confinement strength ω is thoroughly investigated. A combination of rigorous analysis and extensive, highly accurate numerical calculations reveals the presence of only one positive-valued natural amplitude ("the normal sign pattern") for all ω ≥1/2 . More importantly, it is shown that unusual, weakly occupied natural orbitals (NOs) corresponding to additional positive-valued natural amplitudes emerge upon sufficient weakening of the confinement. These solitonic NOs, whose shapes remain almost invariant as their radial positions drift toward infinity upon the critical values of ω being approached from below, exhibit strong radial localization. Their asymptotic properties are extracted from the numerical data and their relevance to calculations on fully Coulombic systems is discussed.
International Nuclear Information System (INIS)
Charpak, G.
2000-01-01
In this article G.Charpak presents the principles on which particle detection is based. Particle accelerators are becoming more and more powerful and require new detectors able to track the right particle in a huge flux of particles. The gigantic size of detectors in high energy physics is often due to the necessity of getting a long enough trajectory in a magnetic field in order to deduce from the curvature an accurate account of impulses in the reaction. (A.C.)
Isochronous Cyclotron Closed Equilibrium Orbit Calculation Program Description
Kian, I N; Tarashkevich, R
2003-01-01
The Equilibrium Orbit Research Program - EORP, written in C++ with the use of Visual C++ is described. The program is intended for the calculation of the particle rotation frequency and particle kinetic energy in the closed equilibrium orbits of an isochronous cyclotron, where the closed equilibrium orbits are described through the radius and particle momentum angle: r_{eo}(\\theta) and \\varphi_{p}(\\theta). The program algorithm was developed on the basis of articles, lecture notes and original analytic calculations. The results of calculations by the EORP were checked and confirmed by using the results of calculations by the numerical methods. The discrepancies between the EORP results and the numerical method results for the calculations of the particle rotation frequency and particle kinetic energy are within the limits of \\pm1\\cdot10^{-4}. The EORP results and the numerical method results for the calculations of r_{eo}(\\theta) and \\varphi_{p}(\\theta) practically coincide. All this proves the accuracy of ca...
Control of open end plasma flow utilizing orbital stochasticity
International Nuclear Information System (INIS)
Hojo, Hitoshi
1995-01-01
It has been known that the control of plasma outside the confinement region of diverter plasma and others in a magnetic field confinement device is very important for improveing the confinement of bulk plasma. The control of plasma outside a confinement region bears two roles, one is the reduction of the thermal load on a diverter plate and others due to the plasma particles lost from the confinement region, and another is the restriction of the back flow of cold plasma and impurities generated outside the confinement region to a bulk plasma region. In this study, the new method of controlling plasma outside a confinement region called magnetic diverter is considered. To the plasma particles advancing along magnetic force lines, the reflection and capture of the plasma particles occur in the region of orbital stochasticity, and the thermal load on an end plate and the reverse flow to a bulk plasma region are restricted. The numerical computation model used regarding the particle control utilizing the orbital stochasticity and the results of calculating the orbit of plasma particles in a magnetic field are reported. (K.I.)
Isochronous cyclotron closed equilibrium orbit calculation program description
International Nuclear Information System (INIS)
Kiyan, I.N.; Vorozhtsov, S.B.; Tarashkevich, R.
2003-01-01
The Equilibrium Orbit Research Program - EORP, written in C++ with the use of Visual C++ is described. The program is intended for the calculation of the particle rotation frequency and particle kinetic energy in the closed equilibrium orbits of an isochronous cyclotron, where the closed equilibrium orbits are described through the radius and particle momentum angle: r eo (θ) and φ p (θ). The program algorithm was developed on the basis of articles, lecture notes and original analytic calculations. The results of calculations by the EORP were checked and confirmed by using the results of calculations by the numerical methods. The discrepancies between the EORP results and the numerical method results for the calculations of the particle rotation frequency and particle kinetic energy are within the limits of ±1·10 -4 . The EORP results and the numerical method results for the calculations of r eo (θ) and φ p (θ) practically coincide. All this proves the accuracy of calculations by the EORP for the isochronous cyclotrons with the azimuthally varied fields. As is evident from the results of calculations, the program can be used for the calculations of both straight - sector and spiral-sector isochronous cyclotrons. (author)
International Nuclear Information System (INIS)
Chinowsky, W.
1989-01-01
Work done in the mid 1950s at Brookhaven National Laboratory on strange particles is described. Experiments were done on the Cosmotron. The author describes his own and others' work on neutral kaons, lambda and theta particles and points out the theoretical gap between predictions and experimental findings. By the end of the decade, the theory of strange particles was better understood. (UK)
International Nuclear Information System (INIS)
Trippe, S; Gillessen, S; Ott, T; Eisenhauer, F; Paumard, T; Martins, F; Genzel, R; Schoedel, R; Eckart, A; Alexander, T
2006-01-01
In this article we present and discuss the latest results from the observations of stars (''S-stars'') orbiting Sgr A* . With improving data quality the number of observed S-stars has increased substantially in the last years. The combination of radial velocity and proper motion information allows an ever more precise determination of orbital parameters and of the mass of and the distance to the supermassive black hole in the centre of the Milky Way. Additionally, the orbital solutions allow us to verify an agreement between the NIR source Sgr A* and the dynamical centre of the stellar orbits to within 2 mas
Accelerated testing for synchronous orbits
Mcdermott, P.
1981-01-01
Degradation of batteries during synchronous orbits is analyzed. Discharge and recharge rates are evaluated. The functional relationship between charge rate and degradation is mathematically determined.
The conservation of orbital symmetry
Woodward, R B
2013-01-01
The Conservation of Orbital Symmetry examines the principle of conservation of orbital symmetry and its use. The central content of the principle was that reactions occur readily when there is congruence between orbital symmetry characteristics of reactants and products, and only with difficulty when that congruence does not obtain-or to put it more succinctly, orbital symmetry is conserved in concerted reaction. This principle is expected to endure, whatever the language in which it may be couched, or whatever greater precision may be developed in its application and extension. The book ope
THEORY OF SECULAR CHAOS AND MERCURY'S ORBIT
International Nuclear Information System (INIS)
Lithwick, Yoram; Wu Yanqin
2011-01-01
We study the chaotic orbital evolution of planetary systems, focusing on secular (i.e., orbit-averaged) interactions, which dominate on long timescales. We first focus on the evolution of a test particle that is forced by multiple planets. To linear order in eccentricity and inclination, its orbit precesses with constant frequencies. But nonlinearities modify the frequencies, and can shift them into and out of resonance with either the planets' eigenfrequencies (forming eccentricity or inclination secular resonances), or with linear combinations of those frequencies (forming mixed high-order secular resonances). The overlap of these nonlinear secular resonances drives secular chaos. We calculate the locations and widths of nonlinear secular resonances, display them together on a newly developed map (the 'map of the mean momenta'), and find good agreement between analytical and numerical results. This map also graphically demonstrates how chaos emerges from overlapping secular resonances. We then apply this newfound understanding to Mercury to elucidate the origin of its orbital chaos. We find that since Mercury's two free precession frequencies (in eccentricity and inclination) lie within ∼25% of two other eigenfrequencies in the solar system (those of the Jupiter-dominated eccentricity mode and the Venus-dominated inclination mode), secular resonances involving these four modes overlap and cause Mercury's chaos. We confirm this with N-body integrations by showing that a slew of these resonant angles alternately librate and circulate. Our new analytical understanding allows us to calculate the criterion for Mercury to become chaotic: Jupiter and Venus must have eccentricity and inclination of a few percent. The timescale for Mercury's chaotic diffusion depends sensitively on the forcing. As it is, Mercury appears to be perched on the threshold for chaos, with an instability timescale comparable to the lifetime of the solar system.
PyORBIT: A Python Shell For ORBIT
Energy Technology Data Exchange (ETDEWEB)
Jean-Francois Ostiguy; Jeffrey Holmes
2003-07-01
ORBIT is code developed at SNS to simulate beam dynamics in accumulation rings and synchrotrons. The code is structured as a collection of external C++ modules for SuperCode, a high level interpreter shell developed at LLNL in the early 1990s. SuperCode is no longer actively supported and there has for some time been interest in replacing it by a modern scripting language, while preserving the feel of the original ORBIT program. In this paper, we describe a new version of ORBIT where the role of SuperCode is assumed by Python, a free, well-documented and widely supported object-oriented scripting language. We also compare PyORBIT to ORBIT from the standpoint of features, performance and future expandability.
Orbital Chondroma: A rare mesenchymal tumor of orbit
Directory of Open Access Journals (Sweden)
Ruchi S Kabra
2015-01-01
Full Text Available While relatively common in the skeletal system, cartilaginous tumors are rarely seen originating from the orbit. Here, we report a rare case of an orbital chondroma. A 27-year-old male patient presented with a painless hard mass in the superonasal quadrant (SNQ of left orbit since 3 months. On examination, best-corrected visual acuity of both eyes was 20/20, with normal anterior and posterior segment with full movements of eyeballs and normal intraocular pressure. Computerized tomography scan revealed well defined soft tissue density lesion in SNQ of left orbit. Patient was operated for anteromedial orbitotomy under general anesthesia. Mass was excised intact and sent for histopathological examination (HPE. HPE report showed lobular aggregates of benign cartilaginous cells with mild atypia suggesting of benign cartilaginous tumor - chondroma. Very few cases of orbital chondroma have been reported in literature so far.
PyORBIT: A Python Shell For ORBIT
International Nuclear Information System (INIS)
Jean-Francois Ostiguy; Jeffrey Holmes
2003-01-01
ORBIT is code developed at SNS to simulate beam dynamics in accumulation rings and synchrotrons. The code is structured as a collection of external C++ modules for SuperCode, a high level interpreter shell developed at LLNL in the early 1990s. SuperCode is no longer actively supported and there has for some time been interest in replacing it by a modern scripting language, while preserving the feel of the original ORBIT program. In this paper, we describe a new version of ORBIT where the role of SuperCode is assumed by Python, a free, well-documented and widely supported object-oriented scripting language. We also compare PyORBIT to ORBIT from the standpoint of features, performance and future expandability
Orbital motions as gradiometers for post-Newtonian tidal effects
Directory of Open Access Journals (Sweden)
Lorenzo eIorio
2014-08-01
Full Text Available The direct long-term changes occurring in the orbital dynamics of a local gravitationally bound binary system S due to the post-Newtonian tidal acceleration caused by an external massive source are investigated. A class of systems made of a test particle m rapidly orbiting with orbital frequency nb an astronomical body of mass M which, in turn, slowly revolves around a distantobject of mass M with orbital frequency nb'<< □ nb is considered. The characteristic frequenciesof the non-Keplerian orbital variations of m and of M itself are assumed to be negligible withrespect to both nb and nb'. General expressions for the resulting Newtonian and post-Newtoniantidal orbital shifts of m are obtained. The future missions BepiColombo and JUICE to Mercuryand Ganymede, respectively, are considered in view of a possible detection. The largest effects,of the order of □ 0:1 □□ 0:5 milliarcseconds per year (mas yr□□1, occur for the Ganymede orbiterof the JUICE mission. Although future improvements in spacecraft tracking and orbit determina14tion might, perhaps, reach the required sensitivity, the systematic bias represented by the otherknown orbital perturbations of both Newtonian and post-Newtonian origin would be overwhel16ming. The realization of a dedicated artificial mini-planetary system to be carried onboard andEarth-orbiting spacecraft is considered as well. Post-Newtonian tidal precessions as large as1 □□ 102 mas yr□□1 could be obtained, but the quite larger Newtonian tidal effects would be amajor source of systematic bias because of the present-day percent uncertainty in the product of the Earth’s mass times the Newtonian gravitational parameter.
Plasma particle drifts due to traveling waves with cyclotron frequencies
International Nuclear Information System (INIS)
Hatakeyama, Rikizo; Sato, Naoyuki; Sato, Noriyoshi
1991-01-01
A particle orbit theory yields that traveling waves with cyclotron frequencies give rise to charged particle drifts perpendicular both to the wave propagation and external magnetic field lines. The result is applicable to particle-flux control of magnetized plasmas. (author)
ORBIT : BEAM DYNAMICS CALCULATIONS FOR HIGH - INTENSITY RINGS
International Nuclear Information System (INIS)
HOLMES, J.A.; DANILOV, V.; GALAMBOS, J.; SHISHLO, A.; COUSINEAU, S.; CHOU, W.; MICHELOTTI, L.; OSTIGUY, F.; WEI, J.
2002-01-01
We are developing a computer code, ORBIT, specifically for beam dynamics calculations in high-intensity rings. Our approach allows detailed simulation of realistic accelerator problems. ORBIT is a particle-in-cell tracking code that transports bunches of interacting particles through a series of nodes representing elements, effects, or diagnostics that occur in the accelerator lattice. At present, ORBIT contains detailed models for strip-foil injection including painting and foil scattering; rf focusing and acceleration; transport through various magnetic elements; longitudinal and transverse impedances; longitudinal, transverse, and three-dimensional space charge forces; collimation and limiting apertures; and the calculation of many useful diagnostic quantities. ORBIT is an object-oriented code, written in C++ and utilizing a scripting interface for the convenience of the user. Ongoing improvements include the addition of a library of accelerator maps, BEAMLINE/MXYZPTLK the introduction of a treatment magnet errors and fringe fields; the conversion of the scripting interface to the standard scripting language, Python; and the parallelization of the computations using MPI. The ORBIT code is an open source, powerful, and convenient tool for studying beam dynamics in high-intensity rings
Spot: a new Monte Carlo solver for fast alpha particles
International Nuclear Information System (INIS)
Schneider, M.; Eriksson, L.G.; Basiuk, V.; Imbeaux, F.
2004-01-01
The predictive transport code CRONOS has been augmented by an orbit following Monte Carlo code, SPOT (Simulation of Particle Orbits in a Tokamak). The SPOT code simulates the dynamics of nonthermal particles, and takes into account effects of finite orbit width and collisional transport of fast ions. Recent developments indicate that it might be difficult to avoid, at least transiently, current holes in a reactor. They occur already on existing tokamaks during advanced tokamak scenarios. The SPOT code has been used to study the alpha particle behaviour in the presence of current holes for both JET and ITER relevant parameters. (authors)
Size Dependence of Dust Distribution around the Earth Orbit
Energy Technology Data Exchange (ETDEWEB)
Ueda, Takahiro; Takeuchi, Taku [Department of Earth and Planetary Sciences, Tokyo Institute of Technology, Meguro, Tokyo, 152-8551 (Japan); Kobayashi, Hiroshi; Ishihara, Daisuke; Kondo, Toru; Kaneda, Hidehiro, E-mail: t.ueda@geo.titech.ac.jp [Graduate School of Science, Nagoya University, Nagoya, Aichi, 464-8602 (Japan)
2017-05-01
In the solar system, interplanetary dust particles (IDPs) originating mainly from asteroid collisions and cometary activities drift to Earth orbit due to Poynting–Robertson drag. We analyzed the thermal emission from IDPs that was observed by the first Japanese infrared astronomical satellite, AKARI . The observed surface brightness in the trailing direction of the Earth orbit is 3.7% greater than that in the leading direction in the 9 μ m band and 3.0% in the 18 μ m band. In order to reveal dust properties causing leading–trailing surface brightness asymmetry, we numerically integrated orbits of the Sun, the Earth, and a dust particle as a restricted three-body problem including radiation from the Sun. The initial orbits of particles are determined according to the orbits of main-belt asteroids or Jupiter-family comets. Orbital trapping in mean motion resonances results in a significant leading–trailing asymmetry so that intermediate sized dust (∼10–100 μ m) produces a greater asymmetry than zodiacal light. The leading–trailing surface brightness difference integrated over the size distribution of the asteroidal dust is obtained to be 27.7% and 25.3% in the 9 μ m and 18 μ m bands, respectively. In contrast, the brightness difference for cometary dust is calculated as 3.6% and 3.1% in the 9 μ m and 18 μ m bands, respectively, if the maximum dust radius is set to be s {sub max} = 3000 μ m. Taking into account these values and their errors, we conclude that the contribution of asteroidal dust to the zodiacal infrared emission is less than ∼10%, while cometary dust of the order of 1 mm mainly accounts for the zodiacal light in infrared.
Size Dependence of Dust Distribution around the Earth Orbit
International Nuclear Information System (INIS)
Ueda, Takahiro; Takeuchi, Taku; Kobayashi, Hiroshi; Ishihara, Daisuke; Kondo, Toru; Kaneda, Hidehiro
2017-01-01
In the solar system, interplanetary dust particles (IDPs) originating mainly from asteroid collisions and cometary activities drift to Earth orbit due to Poynting–Robertson drag. We analyzed the thermal emission from IDPs that was observed by the first Japanese infrared astronomical satellite, AKARI . The observed surface brightness in the trailing direction of the Earth orbit is 3.7% greater than that in the leading direction in the 9 μ m band and 3.0% in the 18 μ m band. In order to reveal dust properties causing leading–trailing surface brightness asymmetry, we numerically integrated orbits of the Sun, the Earth, and a dust particle as a restricted three-body problem including radiation from the Sun. The initial orbits of particles are determined according to the orbits of main-belt asteroids or Jupiter-family comets. Orbital trapping in mean motion resonances results in a significant leading–trailing asymmetry so that intermediate sized dust (∼10–100 μ m) produces a greater asymmetry than zodiacal light. The leading–trailing surface brightness difference integrated over the size distribution of the asteroidal dust is obtained to be 27.7% and 25.3% in the 9 μ m and 18 μ m bands, respectively. In contrast, the brightness difference for cometary dust is calculated as 3.6% and 3.1% in the 9 μ m and 18 μ m bands, respectively, if the maximum dust radius is set to be s max = 3000 μ m. Taking into account these values and their errors, we conclude that the contribution of asteroidal dust to the zodiacal infrared emission is less than ∼10%, while cometary dust of the order of 1 mm mainly accounts for the zodiacal light in infrared.
Infected orbital cyst following exenteration.
Barak, A; Hirsh, A; Rosner, M; Rosen, N
1996-09-01
An orbital cyst is a rare complication of orbital trauma and exenteration. Infections of such cysts have not been described, and are potentially dangerous unless treated immediately. The authors describe a case of delayed treatment of such an infected cyst, which resolved following surgical drainage. The potentially hazardous outcome makes knowledge of such cases important.
DEFF Research Database (Denmark)
Ramos, Juan David Hincapie; Tabard, Aurélien; Bardram, Jakob
2010-01-01
We introduce GridOrbit, a public awareness display that visualizes the activity of a community grid used in a biology laboratory. This community grid executes bioin-formatics algorithms and relies on users to donate CPU cycles to the grid. The goal of GridOrbit is to create a shared awareness about...
Diplopia and Orbital Wall Fractures
Boffano, P.; Roccia, F.; Gallesio, C.; Karagozoglu, K.H.; Forouzanfar, T.
2014-01-01
Diplopia is a symptom that is frequently associated with orbital wall fractures. The aim of this article was to present the incidence and patterns of diplopia after orbital wall blow-out fractures in 2 European centers, Turin and Amsterdam, and to identify any correlation between this symptom and
Diplopia and orbital wall fractures
Boffano, P.; Roccia, F.; Gallesio, C.; Karagozoglu, K.H.; Forouzanfar, T.
2014-01-01
Diplopia is a symptom that is frequently associated with orbital wall fractures. The aim of this article was to present the incidence and patterns of diplopia after orbital wall blow-out fractures in 2 European centers, Turin and Amsterdam, and to identify any correlation between this symptom and
Ripple enhanced transport of suprathermal alpha particles
International Nuclear Information System (INIS)
Tani, K.; Takizuka, T.; Azumi, M.
1986-01-01
The ripple enhanced transport of suprathermal alpha particles has been studied by the newly developed Monte-Carlo code in which the motion of banana orbit in a toroidal field ripple is described by a mapping method. The existence of ripple-resonance diffusion has been confirmed numerically. We have developed another new code in which the radial displacement of banana orbit is given by the diffusion coefficients from the mapping code or the orbit following Monte-Carlo code. The ripple loss of α particles during slowing down has been estimated by the mapping model code as well as the diffusion model code. From the comparison of the results with those from the orbit-following Monte-Carlo code, it has been found that all of them agree very well. (author)
The Carter constant for inclined orbits about a massive Kerr black hole: I. Circular orbits
Energy Technology Data Exchange (ETDEWEB)
Komorowski, P G; Valluri, S R; Houde, M, E-mail: pkomorow@uwo.c, E-mail: valluri@uwo.c, E-mail: mhoude2@uwo.c [Department of Physics and Astronomy, University of Western Ontario, London, Ontario (Canada)
2010-11-21
In an extreme binary black hole system, an orbit will increase its angle of inclination ({iota}) as it evolves in Kerr spacetime. We focus our attention on the behaviour of the Carter constant (Q) for near-polar orbits, and develop an analysis that is independent of and complements radiation-reaction models. For a Schwarzschild black hole, the polar orbits represent the abutment between the prograde and retrograde orbits at which Q is at its maximum value for given values of the latus rectum ({tilde l}) and the eccentricity (e). The introduction of spin ({tilde S}={vert_bar}J{vert_bar}/M{sup 2}) to the massive black hole causes this boundary, or abutment, to be moved towards greater orbital inclination; thus, it no longer cleanly separates prograde and retrograde orbits. To characterize the abutment of a Kerr black hole (KBH), we first investigated the last stable orbit (LSO) of a test-particle about a KBH, and then extended this work to general orbits. To develop a better understanding of the evolution of Q we developed analytical formulae for Q in terms of {tilde l}, e and {tilde S} to describe elliptical orbits at the abutment, polar orbits and LSOs. By knowing the analytical form of {partial_derivative}Q/{partial_derivative}{tilde l} at the abutment, we were able to test a 2PN flux equation for Q. We also used these formulae to numerically calculate the {partial_derivative}{iota}/{partial_derivative}{tilde l} of hypothetical circular orbits that evolve along the abutment. From these values we have determined that {partial_derivative}{iota}/{partial_derivative}{tilde l} = -(122.7{tilde S} - 36{tilde S}{sup 3}){tilde l}{sup -11/2} - (63/2 {tilde S} + 35/4 {tilde S}{sup 3}){tilde l}{sup -9/2} - 15/2 {tilde S}{tilde l}{sup -7/2} - 9/2 {tilde S}{tilde l}{sup -5/2}. By taking the limit of this equation for {tilde l} {yields} {infinity}, and comparing it with the published result for the weak-field radiation reaction, we found the upper limit on
Innermost stable circular orbit of Kerr-MOG black hole
Energy Technology Data Exchange (ETDEWEB)
Lee, Hyun-Chul; Han, Yong-Jin [Soonchunhyang University, Department of Physics, Asan (Korea, Republic of)
2017-10-15
We study the innermost stable circular orbit (ISCO) of the metric of the Kerr black hole in modified gravity (Kerr-MOG black hole), which is one of the exact solutions of the field equation of modified gravity in the strong gravity regime. The Kerr-MOG metric is constructed; it is the commonly known Kerr metric in Boyer-Lindquist coordinates by adding a repulsive term like the Yukawa force, which is explained in quantum gravity. In this paper, we numerically calculate the circular orbit of a photon and the ISCO of a test particle of Kerr-MOG black holes. (orig.)
Equatorial circular orbits in the Kerr-de Sitter spacetimes
International Nuclear Information System (INIS)
Stuchlik, Zdenek; Slany, Petr
2004-01-01
Equatorial motion of test particles in Kerr-de Sitter spacetimes is considered. Circular orbits are determined, their properties are discussed for both black-hole and naked-singularity spacetimes, and their relevance for thin accretion disks is established. The circular orbits constitute two families that coalesce at the so-called static radius. The orientation of the motion along the circular orbits is, in accordance with case of asymptotically flat Kerr spacetimes, defined by relating the motion to the locally nonrotating frames. The minus-family orbits are all counterrotating, while the plus-family orbits are usually corotating relative to these frames. However, the plus-family orbits become counterrotating in the vicinity of the static radius in all Kerr-de Sitter spacetimes, and they become counterrotating in the vicinity of the ring singularity in Kerr-de Sitter naked-singularity spacetimes with a low enough rotational parameter. In such spacetimes, the efficiency of the conversion of the rest energy into heat energy in the geometrically thin plus-family accretion disks can reach extremely high values exceeding the efficiency of the annihilation process. The transformation of a Kerr-de Sitter naked singularity into an extreme black hole due to accretion in the thin disks is briefly discussed for both the plus-family and minus-family disks. It is shown that such a conversion leads to an abrupt instability of the innermost parts of the plus-family accretion disks that can have strong observational consequences
Linear and nonlinear stability of periodic orbits in annular billiards
Dettmann, Carl P.; Fain, Vitaly
2017-04-01
An annular billiard is a dynamical system in which a particle moves freely in a disk except for elastic collisions with the boundary and also a circular scatterer in the interior of the disk. We investigate the stability properties of some periodic orbits in annular billiards in which the scatterer is touching or close to the boundary. We analytically show that there exist linearly stable periodic orbits of an arbitrary period for scatterers with decreasing radii that are located near the boundary of the disk. As the position of the scatterer moves away from a symmetry line of a periodic orbit, the stability of periodic orbits changes from elliptic to hyperbolic, corresponding to a saddle-center bifurcation. When the scatterer is tangent to the boundary, the periodic orbit is parabolic. We prove that slightly changing the reflection angle of the orbit in the tangential situation leads to the existence of Kolmogorov-Arnold-Moser islands. Thus, we show that there exists a decreasing to zero sequence of open intervals of scatterer radii, along which the billiard table is not ergodic.
Energy Technology Data Exchange (ETDEWEB)
Raju, M.R.
1993-09-01
Particle therapy has a long history. The experimentation with particles for their therapeutic application got started soon after they were produced in the laboratory. Physicists played a major role in proposing the potential applications in radiotherapy as well as in the development of particle therapy. A brief review of the current status of particle radiotherapy with some historical perspective is presented and specific contributions made by physicists will be pointed out wherever appropriate. The rationale of using particles in cancer treatment is to reduce the treatment volume to the target volume by using precise dose distributions in three dimensions by using particles such as protons and to improve the differential effects on tumors compared to normal tissues by using high-LET radiations such as neutrons. Pions and heavy ions combine the above two characteristics.
International Nuclear Information System (INIS)
Raju, M.R.
1993-01-01
Particle therapy has a long history. The experimentation with particles for their therapeutic application got started soon after they were produced in the laboratory. Physicists played a major role in proposing the potential applications in radiotherapy as well as in the development of particle therapy. A brief review of the current status of particle radiotherapy with some historical perspective is presented and specific contributions made by physicists will be pointed out wherever appropriate. The rationale of using particles in cancer treatment is to reduce the treatment volume to the target volume by using precise dose distributions in three dimensions by using particles such as protons and to improve the differential effects on tumors compared to normal tissues by using high-LET radiations such as neutrons. Pions and heavy ions combine the above two characteristics
CERN. Geneva
2007-01-01
The understanding of the Universe at the largest and smallest scales traditionally has been the subject of cosmology and particle physics, respectively. Studying the evolution of the Universe connects today's large scales with the tiny scales in the very early Universe and provides the link between the physics of particles and of the cosmos. This series of five lectures aims at a modern and critical presentation of the basic ideas, methods, models and observations in today's particle cosmology.
International Nuclear Information System (INIS)
Kamal, Anwar
2014-01-01
Provides step-by-step derivations. Contains numerous tables and diagrams. Supports learning and teaching with numerous worked examples, questions and problems with answers. Sketches also the historical development of the subject. This textbook teaches particle physics very didactically. It supports learning and teaching with numerous worked examples, questions and problems with answers. Numerous tables and diagrams lead to a better understanding of the explanations. The content of the book covers all important topics of particle physics: Elementary particles are classified from the point of view of the four fundamental interactions. The nomenclature used in particle physics is explained. The discoveries and properties of known elementary particles and resonances are given. The particles considered are positrons, muon, pions, anti-protons, strange particles, neutrino and hadrons. The conservation laws governing the interactions of elementary particles are given. The concepts of parity, spin, charge conjugation, time reversal and gauge invariance are explained. The quark theory is introduced to explain the hadron structure and strong interactions. The solar neutrino problem is considered. Weak interactions are classified into various types, and the selection rules are stated. Non-conservation of parity and the universality of the weak interactions are discussed. Neutral and charged currents, discovery of W and Z bosons and the early universe form important topics of the electroweak interactions. The principles of high energy accelerators including colliders are elaborately explained. Additionally, in the book detectors used in nuclear and particle physics are described. This book is on the upper undergraduate level.
Chang, Manchium (Inventor); Colvin, Michael S. (Inventor)
1989-01-01
Magnetic polymer particles are formed by swelling porous, polymer particles and impregnating the particles with an aqueous solution of precursor magnetic metal salt such as an equimolar mixture of ferrous chloride and ferric chloride. On addition of a basic reagent such as dilute sodium hydroxide, the metal salts are converted to crystals of magnetite which are uniformly contained througout the pores of the polymer particle. The magnetite content can be increased and neutral buoyancy achieved by repetition of the impregnaton and neutralization steps to adjust the magnetite content to a desired level.
On the formation of an instantaneous orbit in a synchrotron
International Nuclear Information System (INIS)
Bashmakov, Yu.A.; Karpov, V.A.
1985-01-01
In the process of injection into a synchrotron amplitudes of particle betatron oscillations can be comparable with the dimensions of the synchrotron working region, which means that special attention should be paid to the formation of the optimum instantaneous orbit. Basides, a necessity to calculate the orbit frequently arises at the end of the acceleration cycle, when particle dump onto internal targets or their extraction from the synchrotron take place. In the paper the method for calculation of particle trajectories in the synchrotron is described. According to the method the program of numerical calculation of both separate particle trajectories and closed instantaneous orbit was developed. The method suggested is based on the presentation of the accelerator magnetic structure as a sequential set of discrete elements. All the elements can be divided into the following main groups: free rectilinear gaps, rectilinear gaps with stray magnetic field, magnetic sectors, rectilinear gaps with accelerating electric field. The calculations made according to the method described have shown its high efficiency. The program developed is used for the simulation of the injection into the ''Pakhra'' synchrotron
Directory of Open Access Journals (Sweden)
Sumeet Jain
2016-01-01
Full Text Available Squamous cell carcinoma of the eyelid is the second most common malignant neoplasm of the eye with the incidence of 0.09 and 2.42 cases/100 000 people. Orbital invasion is a rare complication but, if recognized early, can be treated effectively with exenteration. Although with advancements in technology such as computer-aided design and computer-aided manufacturing, material science, and retentive methods like implants, orbital prosthesis with stock ocular prosthesis made of methyl methacrylate retained by anatomic undercuts is quiet effective and should not be overlooked and forgotten. This clinical report describes prosthetic rehabilitation of two male patients with polymethyl methacrylate resin orbital prosthesis after orbital exenteration, for squamous cell carcinoma of the upper eyelid. The orbital prosthesis was sufficiently retained by hard and soft tissue undercuts without any complications. The patients using the prosthesis are quite satisfied with the cosmetic results and felt comfortable attending the social events.
Orbital Evolution and Orbital Phase Resolved Spectroscopy of the ...
Indian Academy of Sciences (India)
binary. We have carried out orbital phase resolved spectroscopy to mea- ... agreement with a simple model of a spherically symmetric stellar wind from the .... has a set of Narrow Field Instruments (NFI) comprising one Low Energy Concen-.
Orbital Infarction due to Sickle Cell Disease without Orbital Pain
Directory of Open Access Journals (Sweden)
Cameron L. McBride
2016-01-01
Full Text Available Sickle cell disease is a hemoglobinopathy that results in paroxysmal arteriolar occlusion and tissue infarction that can manifest in a plurality of tissues. Rarely, these infarcted crises manifest in the bony orbit. Orbital infarction usually presents with acute onset of periorbital tenderness, swelling, erythema, and pain. Soft tissue swelling can result in proptosis and attenuation of extraocular movements. Expedient diagnosis of sickle cell orbital infarction is crucial because this is a potentially sight-threatening entity. Diagnosis can be delayed since the presentation has physical and radiographic findings mimicking various infectious and traumatic processes. We describe a patient who presented with sickle cell orbital crisis without pain. This case highlights the importance of maintaining a high index of suspicion in patients with known sickle cell disease or of African descent born outside the United States in a region where screening for hemoglobinopathy is not routine, even when the presentation is not classic.
Computed tomography of orbital myositis
International Nuclear Information System (INIS)
Dresner, S.C.; Rothfus, W.E.; Slamovits, T.L.; Kennerdell, J.S.; Curtin, H.D.
1984-01-01
The computerized tomographic (CT) scans of 11 consecutive patients with orbital myositis were reviewed to better characterize the CT appearance of this condition. The findings in this series differed from those of previous reports in several ways. Multiple muscle involvement predominated. Bilateral involvement was more frequent than previously reported. Enlargement of the tendon as well as the muscle was a frequent finding, but a normal tendinous insertion did not preclude the diagnosis of orbital myositis. Although the CT appearance of orbital myositis is often helpful, the findings are not pathognomonic; correlation with history, clinical findings, and therapeutic response must be considered in making the diagnosis
JSC Orbital Debris Website Description
Johnson, Nicholas L.
2006-01-01
Purpose: The website provides information about the NASA Orbital Debris Program Office at JSC, which is the lead NASA center for orbital debris research. It is recognized world-wide for its leadership in addressing orbital debris issues. The NASA Orbital Debris Program Office has taken the international lead in conducting measurements of the environment and in developing the technical consensus for adopting mitigation measures to protect users of the orbital environment. Work at the center continues with developing an improved understanding of the orbital debris environment and measures that can be taken to control its growth. Major Contents: Orbital Debris research is divided into the following five broad efforts. Each area of research contains specific information as follows: 1) Modeling - NASA scientists continue to develop and upgrade orbital debris models to describe and characterize the current and future debris environment. Evolutionary and engineering models are described in detail. Downloadable items include a document in PDF format and executable software. 2) Measurements - Measurements of near-Earth orbital debris are accomplished by conducting ground-based and space-based observations of the orbital debris environment. The data from these sources provide validation of the environment models and identify the presence of new sources. Radar, optical and surface examinations are described. External links to related topics are provided. 3) Protection - Orbital debris protection involves conducting hypervelocity impact measurements to assess the risk presented by orbital debris to operating spacecraft and developing new materials and new designs to provide better protection from the environment with less weight penalty. The data from this work provides the link between the environment defined by the models and the risk presented by that environment to operating spacecraft and provides recommendations on design and operations procedures to reduce the risk as
Particle acceleration in binaries
Directory of Open Access Journals (Sweden)
Sinitsyna V.G.
2017-01-01
Full Text Available Cygnus X-3 massive binary system is one of the powerful sources of radio and X-ray emission consisting of an accreting compact object, probably a black hole, with a Wolf-Rayet star companion. Based on the detections of ultra high energy gamma-rays by Kiel and Havera Park, Cygnus X-3 has been proposed to be one of the most powerful sources of charged cosmic ray particles in the Galaxy. The results of long-term observations of the Cyg X-3 binary at energies 800 GeV–85 TeV detected by SHALON in 1995 are presented with images, integral spectra and spectral energy distribution. The identification of source with Cygnus X-3 detected by SHALON was secured by the detection of its 4.8 hour orbital period in TeV gamma-rays. During the whole observation period of Cyg X-3 with SHALON significant flux increases were detected at energies above 0.8 TeV. These TeV flux increases are correlated with flaring activity at a lower energy range of X-ray and/or at observations of Fermi LAT as well as with radio emission from the relativistic jets of Cygnus X-3. The variability of very high-energy gamma-radiation and correlation of radiation activity in the wide energy range can provide essential information on particle mechanism production up to very high energies. Whereas, modulation of very high energy emission connected to the orbital motion of the binary system, provides an understanding of the emission processes, nature and location of particle acceleration.
Single-particle Glauber matrix elements
International Nuclear Information System (INIS)
Oset, E.; Strottman, D.
1983-01-01
The single-particle matrix elements of the Glauber profile function are tabulated for harmonic oscillator single-particle wave functions. The tables are presented in such a manner as to be applicable if the hadron--nucleon elementary scattering amplitude is specified by either a partial wave expansion or a Gaussian in momentum transfer squared. The table is complete through the 1 g/sub 9/2/ orbital and contains entries for the 3s/sub 1/2/ orbital for use if realistic wave functions are expanded in terms of harmonic oscillator functions
Classical foundations of many-particle quantum chaos
International Nuclear Information System (INIS)
Gutkin, Boris; Osipov, Vladimir
2016-01-01
In the framework of semiclassical theory the universal properties of quantum systems with classically chaotic dynamics can be accounted for through correlations between partner periodic orbits with small action differences. So far, however, the scope of this approach has been mainly limited to systems of a few particles with low-dimensional phase spaces. In the present work we consider N-particle chaotic systems with local homogeneous interactions, where N is not necessarily small. Based on a model of coupled cat maps we demonstrate emergence of a new mechanism for correlation between periodic orbit actions. In particular, we show the existence of partner orbits which are specific to many-particle systems. For a sufficiently large N these new partners dominate the spectrum of correlating periodic orbits and seem to be necessary for construction of a consistent many-particle semiclassical theory. (paper)
Noriega-Mendoza, H.; Aguilar, L. A.
2018-04-01
We performed high precision, N-body simulations of the cold collapse of initially spherical, collisionless systems using the GYRFALCON code of Dehnen (2000). The collapses produce very prolate spheroidal configurations. After the collapse, the systems are simulated for 85 and 170 half-mass radius dynamical timescales, during which energy conservation is better than 0.005%. We use this period to extract individual particle orbits directly from the simulations. We then use the TAXON code of Carpintero and Aguilar (1998) to classify 1 to 1.5% of the extracted orbits from our final, relaxed configurations: less than 15% are chaotic orbits, 30% are box orbits and 60% are tube orbits (long and short axis). Our goal has been to prove that direct orbit extraction is feasible, and that there is no need to "freeze" the final N-body system configuration to extract a time-independent potential.
Assignment of Nilsson orbitals at superdeformation - identical bands
Energy Technology Data Exchange (ETDEWEB)
Ragnarsson, I [Lund Univ. (Sweden). Dept. of Mathematical Physics
1992-08-01
The relative transition energies of superdeformed rotational bands are used to extract ``effective alignments`` of the valence particles. It is found that the effective alignments give a direct picture of the Nilsson orbitals which are active in {sup 146-150}Gd, i.e., especially the orbitals [651 1/2] and [642 5/2], and that all bands observed in these nuclei can be understood within one consistent scheme. The experimental features are reproduced in calculations using the Nilsson-Strutinsky cranking model. The nearly identical transition energies seen in neighboring odd-proton and even-proton nuclei in the Dy/Tb/Gd region are investigated using the same formalism. Again, a consistent picture seems to emerge where, as suggested previously, the nucleus with a hole in the [301 1/2] Nilsson orbital and the corresponding core nucleus have calculated transition energies which are almost identical over a large range in spin. 2 refs., figs.
Space–time and spatial geodesic orbits in Schwarzschild geometry
Resca, Lorenzo
2018-05-01
Geodesic orbit equations in the Schwarzschild geometry of general relativity reduce to ordinary conic sections of Newtonian mechanics and gravity for material particles in the non-relativistic limit. On the contrary, geodesic orbit equations for a proper spatial submanifold of Schwarzschild metric at any given coordinate-time correspond to an unphysical gravitational repulsion in the non-relativistic limit. This demonstrates at a basic level the centrality and critical role of relativistic time and its intimate pseudo-Riemannian connection with space. Correspondingly, a commonly popularised depiction of geodesic orbits of planets as resulting from the curvature of space produced by the Sun, represented as a rubber sheet dipped in the middle by the weighing of that massive body, is mistaken and misleading for the essence of relativity, even in the non-relativistic limit.
Merriam, M. L.
2002-01-01
Traditional studies of Reusable Launch Vehicle (RLV) designs have focused on designs that are completely reusable except for the fuel. This may not be realistic with current technology . An alternate approach is to look at partially reusable launch vehicles. This raises the question of which parts should be reused and which parts should be expendable. One approach is to consider the cost/pound of returning these parts from orbit. With the shuttle, this cost is about three times the cost/pound of launching payload into orbit. A subtle corollary is that RLVs are much less practical for higher orbits, such as the one on which the International Space Station resides, than they are for low earth orbits.
NASA Orbital Debris Baseline Populations
Krisko, Paula H.; Vavrin, A. B.
2013-01-01
The NASA Orbital Debris Program Office has created high fidelity populations of the debris environment. The populations include objects of 1 cm and larger in Low Earth Orbit through Geosynchronous Transfer Orbit. They were designed for the purpose of assisting debris researchers and sensor developers in planning and testing. This environment is derived directly from the newest ORDEM model populations which include a background derived from LEGEND, as well as specific events such as the Chinese ASAT test, the Iridium 33/Cosmos 2251 accidental collision, the RORSAT sodium-potassium droplet releases, and other miscellaneous events. It is the most realistic ODPO debris population to date. In this paper we present the populations in chart form. We describe derivations of the background population and the specific populations added on. We validate our 1 cm and larger Low Earth Orbit population against SSN, Haystack, and HAX radar measurements.
Lidar Orbital Angular Momentum Sensor
National Aeronautics and Space Administration — The recognition in recent decades that electromagnetic fields have angular momentum (AM) in the form of not only polarization (or spin AM) but also orbital (OAM) has...
Real and Hybrid Atomic Orbitals.
Cook, D. B.; Fowler, P. W.
1981-01-01
Demonstrates that the Schrodinger equation for the hydrogenlike atom separates in both spheroconal and prolate spheroidal coordinates and that these separations provide a sound theoretical basis for the real and hybrid atomic orbitals. (Author/SK)
High Power Orbit Transfer Vehicle
National Research Council Canada - National Science Library
Gulczinski, Frank
2003-01-01
... from Virginia Tech University and Aerophysics, Inc. to examine propulsion requirements for a high-power orbit transfer vehicle using thin-film voltaic solar array technologies under development by the Space Vehicles Directorate (dubbed PowerSail...
Topological imprint for periodic orbits
International Nuclear Information System (INIS)
Martín, Jesús San; Moscoso, Ma José; Gómez, A González
2012-01-01
The more self-crossing points an orbit has the more complex it is. We introduce the topological imprint to characterize crossing points and focus on the period-doubling cascade. The period-doubling cascade topological imprint determines the topological imprint for orbits in chaotic bands. In addition, there is a closer link between this concept and the braids studied by Lettelier et al (2000 J. Phys. A: Math. Gen. 33 1809–25). (paper)
Multi-layered foil capture of micrometeoroids and orbital debris in low Earth orbit
Kearsley, A.; Graham, G.
Much of our knowledge concerning the sub-millimetre orbital debris population that poses a threat to orbiting satellites has been gleaned from examination of surfaces retrieved and subsequently analysed as part of post-flight investigations. The preservation of the hypervelocity impact-derived remnants located on these surfaces is very variable, whether of space debris or micrometeoroid origin. Whilst glass and metallic materials show highly visible impact craters when examined using optical and electron microscopes, complex mixing between the target material and the impacting particle may make unambiguous interpretation of the impactor origin difficult or impossible. Our recent detailed examination of selected multi-layered insulation (MLI) foils from the ISAS Space Flyer Unit (SFU), and our preliminary study of NASA's Trek blanket, exposed on the Mir station, show that these constructions have the potential to preserve abundant residue material of a quality sufficient for detailed analysis. Although there are still limitations on the recognition of certain sources of orbital debris, the foils complement the metal and glass substrates. We suggest that a purpose-built multi-layered foil structure may prove to be extremely effective for rapid collection and unambiguous analysis of impact- derived residues. Such a collector could be used an environmental monitor for ISS, as it would have low mass, high durability, easy deployment, recovery and storage, making it an economically viable and attractive option.
Intrinsic Orbital Angular Momentum States of Neutrons
Cappelletti, Ronald L.; Jach, Terrence; Vinson, John
2018-03-01
It has been shown that single-particle wave functions, of both photons and electrons, can be created with a phase vortex, i.e., an intrinsic orbital angular momentum (OAM). A recent experiment has claimed similar success using neutrons [C. W. Clark et al., Nature, 525, 504 (2015), 10.1038/nature15265]. We show that their results are insufficient to unambiguously demonstrate OAM, and they can be fully explained as phase contrast interference patterns. Furthermore, given the small transverse coherence length of the neutrons in the original experiment, the probability that any neutron was placed in an OAM state is vanishingly small. We highlight the importance of the relative size of the coherence length, which presents a unique challenge for neutron experiments compared to electron or photon work, and we suggest improvements for the creation of neutron OAM states.
Magnetic interactions in strongly correlated systems: Spin and orbital contributions
Energy Technology Data Exchange (ETDEWEB)
Secchi, A., E-mail: a.secchi@science.ru.nl [Radboud University, Institute for Molecules and Materials, 6525 AJ Nijmegen (Netherlands); Lichtenstein, A.I. [Universitat Hamburg, Institut für Theoretische Physik, Jungiusstraße 9, D-20355 Hamburg (Germany); Katsnelson, M.I. [Radboud University, Institute for Molecules and Materials, 6525 AJ Nijmegen (Netherlands)
2015-09-15
We present a technique to map an electronic model with local interactions (a generalized multi-orbital Hubbard model) onto an effective model of interacting classical spins, by requiring that the thermodynamic potentials associated to spin rotations in the two systems are equivalent up to second order in the rotation angles, when the electronic system is in a symmetry-broken phase. This allows to determine the parameters of relativistic and non-relativistic magnetic interactions in the effective spin model in terms of equilibrium Green’s functions of the electronic model. The Hamiltonian of the electronic system includes, in addition to the non-relativistic part, relativistic single-particle terms such as the Zeeman coupling to an external magnetic field, spin–orbit coupling, and arbitrary magnetic anisotropies; the orbital degrees of freedom of the electrons are explicitly taken into account. We determine the complete relativistic exchange tensors, accounting for anisotropic exchange, Dzyaloshinskii–Moriya interactions, as well as additional non-diagonal symmetric terms (which may include dipole–dipole interaction). The expressions of all these magnetic interactions are determined in a unified framework, including previously disregarded features such as the vertices of two-particle Green’s functions and non-local self-energies. We do not assume any smallness in spin–orbit coupling, so our treatment is in this sense exact. Finally, we show how to distinguish and address separately the spin, orbital and spin–orbital contributions to magnetism, providing expressions that can be computed within a tight-binding Dynamical Mean Field Theory.
Transport from non-classical orbits
International Nuclear Information System (INIS)
Christiansen, J.P.
2001-10-01
From the guiding centre orbit invariants it is possible to construct a map of different orbit shapes in a phase space of three dimensionless variables: normalised toroidal radius y, particle pitch angle ξ, normalised orbit width ρ [1, 2, 3]. The map describes the link between two points in phase space: point 1 (y 1 , ξ 1 , ρ) and point 2 (y 2 , ξ 2 , ρ) where y 1 , y 2 denote the orbit intersection points 1 and 2 with the y(R) axis. An algorithm permits the rapid calculation of point 2 when point 1 is given. The orbit drift excursion Δy = y 2 - y 1 is calculated and converted to Δx = x 2 - x 1 where x denotes a dimensionless flux surface label for a given equilibrium. The mono-energetic distribution function f 0 (Δx) is calculated at fixed ρ 0 (energy) and with a uniform pitch distribution for three tokamaks PBX, JET, MAST. These have been selected because of their variation of inverse aspect ratio ε. A fourth and hypothetical tokamak labelled 'NEOC' (neoclassical) is introduced to compare the results obtained with those predicted by neoclassical theory. A strong dependence of f 0 upon ε is established. An appropriate thermal distribution f(Δx) is also calculated for the four tokamaks and this distribution depends on the profile shapes of normalised temperature and normalised density as well as on the topology of the equilibrium. The thermal distribution functions are shown to exceed the levels assumed in neoclassical transport theory: the mean values are two to four times larger. It is shown that one reason for this excess is due to orbits which traverse the central region of the tokamak. The implications of the results obtained for estimates of transport can then be studied. The magnitude of the drift excursion Δx from a given flux surface x yields by itself no transport. In the limit vertical bar δ vertical bar yξρ (Δx) and δ = (δy, δξ, δρ). The former vector can be calculated in the thermal case. The latter vector describes collisionless
Space Tourism: Orbital Debris Considerations
Mahmoudian, N.; Shajiee, S.; Moghani, T.; Bahrami, M.
2002-01-01
Space activities after a phase of research and development, political competition and national prestige have entered an era of real commercialization. Remote sensing, earth observation, and communication are among the areas in which this growing industry is facing competition and declining government money. A project like International Space Station, which draws from public money, has not only opened a window of real multinational cooperation, but also changed space travel from a mere fantasy into a real world activity. Besides research activities for sending man to moon and Mars and other outer planets, space travel has attracted a considerable attention in recent years in the form of space tourism. Four countries from space fairing nations are actively involved in the development of space tourism. Even, nations which are either in early stages of space technology development or just beginning their space activities, have high ambitions in this area. This is worth noting considering their limited resources. At present, trips to space are available, but limited and expensive. To move beyond this point to generally available trips to orbit and week long stays in LEO, in orbital hotels, some of the required basic transportations, living requirements, and technological developments required for long stay in orbit are already underway. For tourism to develop to a real everyday business, not only the price has to come down to meaningful levels, but also safety considerations should be fully developed to attract travelers' trust. A serious hazard to space activities in general and space tourism in particular is space debris in earth orbit. Orbiting debris are man-made objects left over by space operations, hazardous to space missions. Since the higher density of debris population occurs in low earth orbit, which is also the same orbit of interest to space tourism, a careful attention should be paid to the effect of debris on tourism activities. In this study, after a
Orbital dynamics in a storage ring with electrostatic bending
International Nuclear Information System (INIS)
Mane, S.R.
2008-01-01
A storage ring where electrostatic fields contribute to the bending and focusing of the orbital motion has some novel features because, unlike a magnetostatic field, an electrostatic field can change the kinetic energy of the particles. I present analytical formulas to calculate the linear focusing gradient, dispersion, momentum compaction and natural chromaticity for a storage ring with a radial electrostatic field. I solve the formulas explicitly for a weak focusing model.
Transition matrices and orbitals from reduced density matrix theory
Energy Technology Data Exchange (ETDEWEB)
Etienne, Thibaud [Université de Lorraine – Nancy, Théorie-Modélisation-Simulation, SRSMC, Boulevard des Aiguillettes 54506, Vandoeuvre-lès-Nancy (France); CNRS, Théorie-Modélisation-Simulation, SRSMC, Boulevard des Aiguillettes 54506, Vandoeuvre-lès-Nancy (France); Unité de Chimie Physique Théorique et Structurale, Université de Namur, Rue de Bruxelles 61, 5000 Namur (Belgium)
2015-06-28
In this contribution, we report two different methodologies for characterizing the electronic structure reorganization occurring when a chromophore undergoes an electronic transition. For the first method, we start by setting the theoretical background necessary to the reinterpretation through simple tensor analysis of (i) the transition density matrix and (ii) the natural transition orbitals in the scope of reduced density matrix theory. This novel interpretation is made more clear thanks to a short compendium of the one-particle reduced density matrix theory in a Fock space. The formalism is further applied to two different classes of excited states calculation methods, both requiring a single-determinant reference, that express an excited state as a hole-particle mono-excited configurations expansion, to which particle-hole correlation is coupled (time-dependent Hartree-Fock/time-dependent density functional theory) or not (configuration interaction single/Tamm-Dancoff approximation). For the second methodology presented in this paper, we introduce a novel and complementary concept related to electronic transitions with the canonical transition density matrix and the canonical transition orbitals. Their expression actually reflects the electronic cloud polarisation in the orbital space with a decomposition based on the actual contribution of one-particle excitations from occupied canonical orbitals to virtual ones. This approach validates our novel interpretation of the transition density matrix elements in terms of the Euclidean norm of elementary transition vectors in a linear tensor space. A proper use of these new concepts leads to the conclusion that despite the different principles underlying their construction, they provide two equivalent excited states topological analyses. This connexion is evidenced through simple illustrations of (in)organic dyes electronic transitions analysis.
THE ECCENTRIC KOZAI MECHANISM FOR A TEST PARTICLE
International Nuclear Information System (INIS)
Lithwick, Yoram; Naoz, Smadar
2011-01-01
We study the dynamical evolution of a test particle that orbits a star in the presence of an exterior massive planet, considering octupole-order secular interactions. In the standard Kozai mechanism (SKM), the planet's orbit is circular and so the particle conserves vertical angular momentum. As a result, the particle's orbit oscillates periodically, exchanging eccentricity for inclination. However, when the planet's orbit is eccentric, the particle's vertical angular momentum varies and its Kozai oscillations are modulated on longer timescales—we call this the eccentric Kozai mechanism (EKM). The EKM can lead to behavior that is dramatically different from the SKM. In particular, the particle's orbit can flip from prograde to retrograde and back again, and it can reach arbitrarily high eccentricities given enough time. We map out the conditions under which this dramatic behavior (flipping and extreme eccentricities) occurs and show that when the planet's eccentricity is sufficiently high, it occurs quite generically. For example, when the planet's eccentricity exceeds a few percent of the ratio of semimajor axes (outer to inner), around half of randomly oriented test particle orbits will flip and reach extreme eccentricities. The SKM has often been invoked for bringing pairs of astronomical bodies (star-star, planet-star, compact-object pairs) close together. Including the effect of the EKM will enhance the rate at which such matchmaking occurs.
Angles-only relative orbit determination in low earth orbit
Ardaens, Jean-Sébastien; Gaias, Gabriella
2018-06-01
The paper provides an overview of the angles-only relative orbit determination activities conducted to support the Autonomous Vision Approach Navigation and Target Identification (AVANTI) experiment. This in-orbit endeavor was carried out by the German Space Operations Center (DLR/GSOC) in autumn 2016 to demonstrate the capability to perform spaceborne autonomous close-proximity operations using solely line-of-sight measurements. The images collected onboard have been reprocessed by an independent on-ground facility for precise relative orbit determination, which served as ultimate instance to monitor the formation safety and to characterize the onboard navigation and control performances. During two months, several rendezvous have been executed, generating a valuable collection of images taken at distances ranging from 50 km to only 50 m. Despite challenging experimental conditions characterized by a poor visibility and strong orbit perturbations, angles-only relative positioning products could be continuously derived throughout the whole experiment timeline, promising accuracy at the meter level during the close approaches. The results presented in the paper are complemented with former angles-only experience gained with the PRISMA satellites to better highlight the specificities induced by different orbits and satellite designs.
An Orbit Propagation Software for Mars Orbiting Spacecraft
Directory of Open Access Journals (Sweden)
Young-Joo Song
2004-12-01
Full Text Available An orbit propagation software for the Mars orbiting spacecraft has been developed and verified in preparations for the future Korean Mars missions. Dynamic model for Mars orbiting spacecraft has been studied, and Mars centered coordinate systems are utilized to express spacecraft state vectors. Coordinate corrections to the Mars centered coordinate system have been made to adjust the effects caused by Mars precession and nutation. After spacecraft enters Sphere of Influence (SOI of the Mars, the spacecraft experiences various perturbation effects as it approaches to Mars. Every possible perturbation effect is considered during integrations of spacecraft state vectors. The Mars50c gravity field model and the Mars-GRAM 2001 model are used to compute perturbation effects due to Mars gravity field and Mars atmospheric drag, respectively. To compute exact locations of other planets, JPL's DE405 ephemerides are used. Phobos and Deimos's ephemeris are computed using analytical method because their informations are not released with DE405. Mars Global Surveyor's mapping orbital data are used to verify the developed propagator performances. After one Martian day propagation (12 orbital periods, the results show about maximum ±5 meter errors, in every position state components(radial, cross-track and along-track, when compared to these from the Astrogator propagation in the Satellite Tool Kit. This result shows high reliability of the developed software which can be used to design near Mars missions for Korea, in future.
Hilke, Hans Jürgen
1992-01-01
We shall discuss the principles of the main techniques applied to particle detection (including front-end electronics), the construction and performance of some of the devices presently in operation and a few ideas on future developments.
The effect of quadrupole fields on particle confinement in a field-reversed mirror
International Nuclear Information System (INIS)
McColl, D.B.; Berk, H.L.; Hammer, J.; Morse, E.C.
1982-01-01
A particle simulation code has been modified to simulate particle loss caused by quadrupole magnetic fields on a field-reversed mirror plasma device. Since analytic fields are chosen for the equilibrium, the numerical algorithm is highly accurate for long-time integrations of particle orbits. The resultant particle loss due to the quadrupole fields can be competitive with collisional loss in the device
International Nuclear Information System (INIS)
Evans, D.S.
1987-01-01
The problems concerning the aurora posed prior to the war are now either solved in principle or were restated in a more fundamental form. The pre-war hypothesis concerning the nature of the auroral particles and their energies was fully confirmed, with the exception that helium and oxygen ions were identified as participating in the auroral particle precipitation in addition to the protons. The nature of the near-Earth energization processes affecting auroral particles was clarified. Charged particle trajectories in various electric field geometries were modeled. The physical problems have now moved from determining the nature and geometry of the electric fields, which accelerate charged particles near the Earth, to accounting for the existence of these electric fields as a natural consequence of the solar wind's interaction with Earth. Ultimately the reward in continuing the work in auroral and magnetospheric particle dynamics will be a deeper understanding of the subtleties of classical electricity and magnetism as applied to situations not blessed with well-defined and invariant geometries
DEFF Research Database (Denmark)
Angelsky, O. V.; Bekshaev, A. Ya; Maksimyak, P. P.
2012-01-01
flow upon tight focusing of the beam, usually applied for energy flow detection by means of the mechanical action upon probe particles. We propose a two-beam interference technique that results in an appreciable level of spin flow in moderately focused beams and detection of the orbital motion of probe...... particles within a field where the transverse energy circulation is associated exclusively with the spin flow. This result can be treated as the first demonstration of mechanical action of the spin flow of a light field....
Elementary particles and particle interactions
International Nuclear Information System (INIS)
Bethge, K.; Schroeder, U.E.
1986-01-01
This book is a textbook for an introductory course of elementary particle physics. After a general introduction the symmetry principles governing the interactions of elementary particles are discussed. Then the phenomenology of the electroweak and strong interactions are described together with a short introduction to the Weinberg-Salam theory respectively to quantum chromodynamics. Finally a short outlook is given to grand unification with special regards to SU(5) and cosmology in the framework of the current understanding of the fundamental principles of nature. In the appendix is a table of particle properties and physical constants. (HSI) [de
The Eccentric Behavior of Nearly Frozen Orbits
Sweetser, Theodore H.; Vincent, Mark A.
2013-01-01
Frozen orbits are orbits which have only short-period changes in their mean eccentricity and argument of periapse, so that they basically keep a fixed orientation within their plane of motion. Nearly frozen orbits are those whose eccentricity and argument of periapse have values close to those of a frozen orbit. We call them "nearly" frozen because their eccentricity vector (a vector whose polar coordinates are eccentricity and argument of periapse) will stay within a bounded distance from the frozen orbit eccentricity vector, circulating around it over time. For highly inclined orbits around the Earth, this distance is effectively constant over time. Furthermore, frozen orbit eccentricity values are low enough that these orbits are essentially eccentric (i.e., off center) circles, so that nearly frozen orbits around Earth are bounded above and below by frozen orbits.
The method of coadjoint orbits
International Nuclear Information System (INIS)
Delius, G.W.; Van Nieuwenhuizen, P.; Rodgers, V.G.J.
1990-01-01
The method of coadjoint orbits produces for any infinite dimensional Lie (super) algebra A with nontrivial central charge an action for scalar (super) fields which has at least the symmetry A. In this article, the authors try to make this method accessible to a larger audience by analyzing several examples in more detail than in the literature. After working through the Kac-Moody and Virasoro cases, we apply the method to the super Virasoro algebra and reobtain the super-symmetric extension of Polyakov's local nonpolynomial action for two-dimensional quantum gravity. As in the Virasoro case this action corresponds to the coadjoint orbit of a pure central extension. The authors further consider the actions corresponding to the other orbits of the super Virasoro algebra. As a new result the authors construct the actions for the N = 2 super Virasoro algebra
Gravity Probe B orbit determination
International Nuclear Information System (INIS)
Shestople, P; Ndili, A; Parkinson, B W; Small, H; Hanuschak, G
2015-01-01
The Gravity Probe B (GP-B) satellite was equipped with a pair of redundant Global Positioning System (GPS) receivers used to provide navigation solutions for real-time and post-processed orbit determination (OD), as well as to establish the relation between vehicle time and coordinated universal time. The receivers performed better than the real-time position requirement of 100 m rms per axis. Post-processed solutions indicated an rms position error of 2.5 m and an rms velocity error of 2.2 mm s −1 . Satellite laser ranging measurements provided independent verification of the GPS-derived GP-B orbit. We discuss the modifications and performance of the Trimble Advance Navigation System Vector III GPS receivers. We describe the GP-B precision orbit and detail the OD methodology, including ephemeris errors and the laser ranging measurements. (paper)
MRI of orbital hydroxyapatite implants
International Nuclear Information System (INIS)
Flanders, A.E.; De Potter P.; Rao, V.M.; Tom, B.M.; Shields, C.L.; Shields, J.A.
1996-01-01
Our aim was to use MRI for the postsurgical assessment of a new form of integrated orbital implant composed of a porous calcium phosphate hydroxyapatite substrate. We studied ten patients 24-74 years of age who underwent enucleation and implantation of a hydroxyapatite ball; 5-13 months after surgery, each patient was examined by spin-echo MRI, with fat suppression and gadolinium enhancement. Fibrovascular ingrowth was demonstrated in all ten patients as areas of enhancement at the periphery of the hydroxyapatite sphere that extended to the center to a variable degree. The radiologist should aware of the MRI appearances of the coralline hydroxyapatite orbital implant since it is now widely used following enucleation. MRI is a useful means to determine successful incorporation of the substrate into the orbital tissues. The normal pattern of contrast enhancement should not be mistaken for recurrent tumor or infection. (orig.)
Schröer, H.
Orbits of small balls on revolutions solid shells are examined. Which velocity is necessary to stay in balance? The angular velocity remains constant. General revolution solid, revolution cone, revolution ellipsoid, ball, paraboloid and hyperboloid are treated. Chapter 1 represents the frictionless case. Chapter 2 deals with the friction case. The transformation from velocity to the belonging orbit height is calculated in chapter 3. In chapter 4 and 5 the macro revolution solids follow (without and with friction)is treated. The assumption of a homogeneous field is not possible here. The radial gravitational field must be used. In the last chapter we have orbits with non constant angular velocity that can be derived with the Lagrange-equations of the second kind in the frictionless case. Here is also possible to view different revolution solids. The book is recommended to all experimental-, theoretical and mathematical physicists. There is an english and a german edition.
Orbital periods of recurrent novae
International Nuclear Information System (INIS)
Schaefer, B.E.
1990-01-01
The class of recurrent novae (RN) with thermonuclear runaways contains only three systems (T Pyx, U Sco, and V394 CrA), for which no orbital periods are known. This paper presents a series of photometric observations where the orbital periods for all three systems are discovered. T Pyx is found to have sinusoidal modulation with an amplitude of 0.08 mag and a period of 2.3783 h (with a possible alias of 2.6403 h). U Sco is found to be an eclipsing system with an eclipse amplitude of roughly 1.5 mag and an orbital period of 1.2344 days. V394 CrA is found to have sinusoidal modulation with an amplitude of 0.5 mag and a period of 0.7577 days. Thus two out of three RN with thermonuclear runaways (or five out of six for all RN) have evolved companions. 16 refs
Energy Technology Data Exchange (ETDEWEB)
Yamashita, Yasuyuki; Sato, Ryuiti; Sakamoto, Yuji; Kojima, Ryutaro; Takahashi, Mutsumasa; Maruoka, Syouko; Okamura, Ryoichi; Oguni, Tatsuro.
1989-05-01
Sixty five cases with orbital and ocular lesions were evaluated by MRI in comparison with high resolution CT. MRI was performed with spin echo techniques (short TR/TE and long TR/TE) using a 0.22 tesla resistive unit (Toshiba MRT-22A) or a 1.5 tesla superconductive unit (Siemens Magnetom). MRI was superior to CT in (1) detecting ocular lesions and vitreous changes, (2) differentiating a tumor from the adjacent extraocular muscles and optic nerves, (3) identifying the lesion in the orbital apex and demonstrating the posterior extent of the tumor and (4) detecting the abnormal flow in the orbital vascular structures. Although some tumors had specific signal intensities including hemangioma, menigioma, and pseudotumor, majority of tumors revealed non-sepcific signal intensities. CT was superior to MRI in detection for small and calcified lesions as well as visualization of bone details. (author).
Energy Technology Data Exchange (ETDEWEB)
Nakamura, K., E-mail: nakamura@triam.kyushu-u.ac.jp [RIAM, Kyushu University, Kasuga 816-8580 (Japan); Alam, M.M. [IGSES, Kyushu University, Kasuga 816-8580 (Japan); Jiang, Y.Z. [Tsinghua University, Beijing 100084 (China); Mitarai, O. [Tokai University, Kumamoto 862-8652 (Japan); Kurihara, K.; Kawamata, Y.; Sueoka, M.; Takechi, M. [Japan Atomic Energy Agency, Naka 311-0193 (Japan); Hasegawa, M.; Tokunaga, K.; Araki, K.; Zushi, H.; Hanada, K.; Fujisawa, A.; Idei, H.; Nagashima, Y.; Kawasaki, S.; Nakashima, H.; Higashijima, A.; Nagata, T. [RIAM, Kyushu University, Kasuga 816-8580 (Japan); and others
2016-11-01
Highlights: • High energy particle guiding center orbit is calculated as a contour plot of conserved variable. • Current density profile is analyzed based on the orbit-driven current. • Plasma equilibrium is reconstructed by considering the hollow current profile. - Abstract: In the present RF-driven (ECCD) steady-state plasma on QUEST (B{sub t} = 0.25 T, R = 0.68 m, a = 0.40 m), plasma current seems to flow in the open magnetic surface outside of the closed magnetic surface in the low-field region according to plasma current fitting (PCF) method. We consider that the current in the open magnetic surface is due to orbit-driven current by high-energy particles in RF-driven plasma. So based on the analysis of current density profile based on the orbit-driven current, plasma equilibrium is to be calculated. We calculated high energy particles guiding center orbits as a contour plot of conserved variable in Hamiltonian formulation and considered particles initial position with different levels of energy and pitch angles that satisfy resonance condition. Then the profile of orbit-driven current is estimated by multiplying the particle density on the resonance surface and the velocity on the orbits. This analysis shows negative current near the magnetic axis and hollow current profile is expected even if pressure driven current is considered. Considering the hollow current profile shifted toward the low-field region, the equilibrium is fitted by J-EFIT coded by MATLAB.
MESSENGER at Mercury: Early Orbital Operations
McNutt, Ralph L., Jr; Solomon, Sean C.; Bedini, Peter D.; Anderson, Brian J.; Blewett, David T.; Evans, Larry G.; Gold, Robert E.; Krimigis, Stamatios M.; Murchie, Scott L.; Nittler, Larry R.;
2013-01-01
angles. Targeted areas have been selected for spectral coverage into the ultraviolet with the Ultraviolet and Visible Spectrometer (UVVS). MESSENGER's Mercury Laser Altimeter is acquiring topographic profiles when the slant range to Mercury's surface is less than 1800 km, encompassing latitudes from 20 deg. S to the north pole. Topography over the remainder of the southern hemisphere will be derived from stereo imaging, radio occultations, and limb profiles. MESSENGER's radio science experiment is determining Mercury's gravity field from Doppler signals acquired during frequent downlinks. MESSENGER's Magnetometer is measuring the vector magnetic field both within Mercury's magnetosphere and in Mercury's solar wind environment at an instrument sampling rate of up to 20 samples/s. The UVVS is determining the three-dimensional, time-dependent distribution of Mercury's exospheric neutral and ionic species via their emission lines. During each spacecraft orbit, the Energetic Particle Spectrometer measures energetic electrons and ions, and the Fast Imaging Plasma Spectrometer measures the energies and mass per charge of thermal plasma components, both within Mercury's magnetosphere and in Mercury's solar-wind environment. The primary mission observation sequence will continue for one Earth year, until March 2012. An extended mission, currently under discussion with NASA, would add a second year of orbital observations targeting a set of focused follow-on questions that build on observations to date and take advantage of the more active Sun expected during 2012-2013. MESSENGER's total primary mission cost, projected at $446 M in real-year dollars, is comparable to that of Mariner 10 after adjustment for inflation.
Orbital computed tomography for exophthalmos
International Nuclear Information System (INIS)
Kim, Ok Keun; Lee, Hyun; Sol, Chang Hyo; Kim, Byung Soo
1987-01-01
Since exophthalmos is caused by any decrease in the size of bony orbit or occurrence of mass within the rigid orbit, the accurate diagnosis of its causes are essential in determining the therapeutic aims. Exophthalmos is one of the important signs being the indication for orbital computed tomography along with periorbital swelling, visual loss, orbital trauma and diplopia. CT as the diagnostic tool for the cause of exophthalmos not only displays a superb role with uncomparable quality in comparison to any conventional diagnostic methods but also has a decisive role in determining the therapeutic aims and the appropriate operative method when the operation is indicated. The orbital CT was performed from May in 1983 to May in 1985 whose with chief complaints were exophthalmos and 23 cases were confirmed by operation, biopsy, clinical progression or other diagnostic procedures. Here was report thoroughly analyzed 23 cases. The results were as follows : 1. The etiologic disease of exophthalmos were 6 cases of pseudotumor, 4 cases of thyroid ophthalmopathy, 4 cases of maxill ary sinus and nasal cavity Ca., 3 cases of mucocele and 1 case of alveolar soft part sarcoma, osteoma, dermoid cyst, pleomorphic adenoma, meningioma, and C.C.F. each. 2. The origin of the etiologic diseases of exophthalmos were 13 cases of primary within bony orbit and 10 cases of secondary from adjacent structure. 3. The site of lesions were 11 cases of intraconal and extraconal, 10 cases of extraconal, and 2 cases of intraconal origin. 4. The degree of exophthalmos in CT scan was in proportion to the volume of the mass except in the case of thyroid ophthalmopathy. The upper limit of normal range by CT scan using regression line equation was 16.2 mm in approximation. 5. CT was a very useful diagnostic tool in the accurate assessment of the kinds of lesion, its location, and its relationship to adjacent structures in the diagnosis of etiologic diseases of exophthalmos
Orbital computed tomography for exophthalmos
Energy Technology Data Exchange (ETDEWEB)
Kim, Ok Keun; Lee, Hyun; Sol, Chang Hyo; Kim, Byung Soo [College of Medicine, Pusan National University, Busan (Korea, Republic of)
1987-06-15
Since exophthalmos is caused by any decrease in the size of bony orbit or occurrence of mass within the rigid orbit, the accurate diagnosis of its causes are essential in determining the therapeutic aims. Exophthalmos is one of the important signs being the indication for orbital computed tomography along with periorbital swelling, visual loss, orbital trauma and diplopia. CT as the diagnostic tool for the cause of exophthalmos not only displays a superb role with uncomparable quality in comparison to any conventional diagnostic methods but also has a decisive role in determining the therapeutic aims and the appropriate operative method when the operation is indicated. The orbital CT was performed from May in 1983 to May in 1985 whose with chief complaints were exophthalmos and 23 cases were confirmed by operation, biopsy, clinical progression or other diagnostic procedures. Here was report thoroughly analyzed 23 cases. The results were as follows : 1. The etiologic disease of exophthalmos were 6 cases of pseudotumor, 4 cases of thyroid ophthalmopathy, 4 cases of maxill ary sinus and nasal cavity Ca., 3 cases of mucocele and 1 case of alveolar soft part sarcoma, osteoma, dermoid cyst, pleomorphic adenoma, meningioma, and C.C.F. each. 2. The origin of the etiologic diseases of exophthalmos were 13 cases of primary within bony orbit and 10 cases of secondary from adjacent structure. 3. The site of lesions were 11 cases of intraconal and extraconal, 10 cases of extraconal, and 2 cases of intraconal origin. 4. The degree of exophthalmos in CT scan was in proportion to the volume of the mass except in the case of thyroid ophthalmopathy. The upper limit of normal range by CT scan using regression line equation was 16.2 mm in approximation. 5. CT was a very useful diagnostic tool in the accurate assessment of the kinds of lesion, its location, and its relationship to adjacent structures in the diagnosis of etiologic diseases of exophthalmos.
GLONASS orbit/clock combination in VNIIFTRI
Bezmenov, I.; Pasynok, S.
2015-08-01
An algorithm and a program for GLONASS satellites orbit/clock combination based on daily precise orbits submitted by several Analytic Centers were developed. Some theoretical estimates for combine orbit positions RMS were derived. It was shown that under condition that RMS of satellite orbits provided by the Analytic Centers during a long time interval are commensurable the RMS of combine orbit positions is no greater than RMS of other satellite positions estimated by any of the Analytic Centers.
A collision model in plasma particle simulations
International Nuclear Information System (INIS)
Ma Yanyun; Chang Wenwei; Yin Yan; Yue Zongwu; Cao Lihua; Liu Daqing
2000-01-01
In order to offset the collisional effects reduced by using finite-size particles, β particle clouds are used in particle simulation codes (β is the ratio of charge or mass of modeling particles to real ones). The method of impulse approximation (strait line orbit approximation) is used to analyze the scattering cross section of β particle clouds plasmas. The authors can obtain the relation of the value of a and β and scattering cross section (a is the radius of β particle cloud). By using this relation the authors can determine the value of a and β so that the collisional effects of the modeling system is correspondent with the real one. The authors can also adjust the values of a and β so that the authors can enhance or reduce the collisional effects fictitiously. The results of simulation are in good agreement with the theoretical ones
Precise GPS orbits for geodesy
Colombo, Oscar L.
1994-01-01
The Global Positioning System (GPS) has become, in recent years, the main space-based system for surveying and navigation in many military, commercial, cadastral, mapping, and scientific applications. Better receivers, interferometric techniques (DGPS), and advances in post-processing methods have made possible to position fixed or moving receivers with sub-decimeter accuracies in a global reference frame. Improved methods for obtaining the orbits of the GPS satellites have played a major role in these achievements; this paper gives a personal view of the main developments in GPS orbit determination.
Primary orbital squamous cell carcinoma
Directory of Open Access Journals (Sweden)
Ana L. Campos Arbulú
2017-02-01
Full Text Available Primary orbital squamous cell carcinoma is a rare entity. There is little published literature. We report a case of primary squamous cell carcinoma of the orbital soft tissues. Surgical resection offered the best treatment for the patient. Complete resection of the lesion was achieved. The patient received adjuvant radiotherapy due to the proximity of the lesion to the surgical margins. Surgical treatment is feasible and should be considered as part of the surgeon's arsenal. However, therapeutic decisions must be made on a case-by-case basis
Orbital resonances around black holes.
Brink, Jeandrew; Geyer, Marisa; Hinderer, Tanja
2015-02-27
We compute the length and time scales associated with resonant orbits around Kerr black holes for all orbital and spin parameters. Resonance-induced effects are potentially observable when the Event Horizon Telescope resolves the inner structure of Sgr A*, when space-based gravitational wave detectors record phase shifts in the waveform during the resonant passage of a compact object spiraling into the black hole, or in the frequencies of quasiperiodic oscillations for accreting black holes. The onset of geodesic chaos for non-Kerr spacetimes should occur at the resonance locations quantified here.
Orbital effects in actinide systems
International Nuclear Information System (INIS)
Lander, G.H.
1983-01-01
Actinide magnetism presents a number of important challenges; in particular, the proximity of 5f band to the Fermi energy gives rise to strong interaction with both d and s like conduction electrons, and the extended nature of the 5f electrons means that they can interact with electron orbitals from neighboring atoms. Theory has recently addressed these problems. Often neglected, however, is the overwhelming evidence for large orbital contributions to the magnetic properties of actinides. Some experimental evidence for these effects are presented briefly in this paper. They point, clearly incorrectly, to a very localized picture for the 5f electrons. This dichotomy only enhances the nature of the challenge
AA, closed orbit observation pickup
1980-01-01
Electrostatic pickups around the circumference of the AA served for the measurement of the closed orbits across the wide momentum range of +- 3% to either side of central orbit. The pickups were of the "shoebox" type, with diagonal cuts, a horizontal and a vertical one mechanically coupled together. They were located where they would not require extra space. The small ones, like the one we see here, were inserted into the vacuum chamber of the BLG (long and narrow) bending magnets. See also 8001372, 8010042, 8010045
AA, closed orbit observation pickup
CERN PhotoLab
1980-01-01
Electrostatic pickups around the circumference of the AA served for the measurement of the closed orbits across the wide momentum range of +- 3% to either side of central orbit. The pickups were of the "shoebox" type, with diagonal cuts, a horizontal and a vertical one mechanically coupled together. They were located where they would not require extra space. The wide ones (very wide indeed: 70 cm), like the one we see here, were placed inside the vacuum chamber of the wide quadrupoles QFW, at maximum dispersion. See also 8001372, 8001383, 8010045
AA, closed orbit observation pickup
CERN PhotoLab
1980-01-01
Electrostatic pickups around the circumference of the AA served for the measurement of the closed orbits across the wide momentum range of +- 3% to either side of central orbit. The pickups were of the "shoebox" type, with diagonal cuts, a horizontal and a vertical one mechanically coupled together. They were located where they would not require extra space. The wide ones (very wide indeed: 70 cm), like the one we see here, were placed inside the vacuum chamber of the wide quadrupoles, QFW, at maximum dispersion. See also 8001372,8001383, 8010042
AA, closed orbit observation pickup
CERN PhotoLab
1980-01-01
Electrostatic pickups around the circumference of the AA served for the measurement of the closed orbits across the wide momentum range of +- 3% to either side of central orbit. The pickups were of the "shoebox" type, with diagonal cuts, a horizontal and a vertical one mechanically coupled together. They were located where they would not require extra space. The small ones, like the one we see here, were inserted into the vacuum chamber of the BLG (long and narrow) bending magnets. Werner Sax contemplates his achievement. See also 8001383, 8010042, 8010045.
Energy and the Elliptical Orbit
Nettles, Bill
2009-03-01
In the January 2007 issue of The Physics Teacher, Prentis, Fulton, Hesse, and Mazzino describe a laboratory exercise in which students use a geometrical analysis inspired by Newton to show that an elliptical orbit and an inverse-square law force go hand in hand. The historical, geometrical, and teamwork aspects of the exercise are useful and important. This paper presents an exercise which uses an energy/angular momentum conservation model for elliptical orbits. This exercise can be done easily by an individual student and on regular notebook-sized paper.
Hilke, Hans Jürgen; Joram, Christian; CERN. Geneva
1991-01-01
Lecture 5: Detector characteristics: ALEPH Experiment cut through the devices and events - Discuss the principles of the main techniques applied to particle detection ( including front-end electronics), the construction and performance of some of the devices presently in operartion and a few ideas on the future performance. Lecture 4-pt. b Following the Scintillators. Lecture 4-pt. a : Scintillators - Used for: -Timing (TOF, Trigger) - Energy Measurement (Calorimeters) - Tracking (Fibres) Basic scintillation processes- Inorganic Scintillators - Organic Scintil - Discuss the principles of the main techniques applied to particle detection ( including front-end electronics), the construction and performance of some of the devices presently in operation and a fiew ideas on future developpement session 3 - part. b Following Calorimeters lecture 3-pt. a Calorimeters - determine energy E by total absorption of charged or neutral particles - fraction of E is transformed into measurable quantities - try to acheive sig...
International Nuclear Information System (INIS)
Samios, N.P.
1993-01-01
I have been asked to review the subject of stable particles, essentially the particles that eventually comprised the meson and baryon octets. with a few more additions -- with an emphasis on the contributions made by experiments utilizing the bubble chamber technique. In this activity, much work had been done by the photographic emulsion technique and cloud chambers-exposed to cosmic rays as well as accelerator based beams. In fact, many if not most of the stable particles were found by these latter two techniques, however, the forte of the bubble chamber (coupled with the newer and more powerful accelerators) was to verify, and reinforce with large statistics, the existence of these states, to find some of the more difficult ones, mainly neutrals and further to elucidate their properties, i.e., spin, parity, lifetimes, decay parameters, etc
Plasma physics via particle simulation
International Nuclear Information System (INIS)
Birdsall, C.K.
1981-01-01
Plasmas are studied by following the motion of many particles in applied and self fields, analytically, experimentally and computationally. Plasmas for magnetic fusion energy devices are very hot, nearly collisionless and magnetized, with scale lengths of many ion gyroradii and Debye lengths. The analytic studies of such plasmas are very difficult as the plasma is nonuniform, anisotropic and nonlinear. The experimental studies have become very expensive in time and money, as the size, density and temperature approach fusion reactor values. Computational studies using many particles and/or fluids have complemented both theories and experiments for many years and have progressed to fully three dimensional electromagnetic models, albeit with hours of running times on the fastest largest computers. Particle simulation methods are presented in some detail, showing particle advance from acceleration to velocity to position, followed by calculation of the fields from charge and current densities and then further particle advance, and so on. Limitations due to the time stepping and use of a spatial grid are given, to avoid inaccuracies and instabilities. Examples are given for an electrostatic program in one dimension of an orbit averaging program, and for a three dimensional electromagnetic program. Applications of particle simulations of plasmas in magnetic and inertial fusion devices continue to grow, as well as to plasmas and beams in peripheral devices, such as sources, accelerators, and converters. (orig.)
Martin, Brian R
2017-01-01
An accessible and carefully structured introduction to Particle Physics, including important coverage of the Higgs Boson and recent progress in neutrino physics. Fourth edition of this successful title in the Manchester Physics series. Includes information on recent key discoveries including : An account of the discovery of exotic hadrons, beyond the simple quark model; Expanded treatments of neutrino physics and CP violation in B-decays; An updated account of ‘physics beyond the standard model’, including the interaction of particle physics with cosmology; Additional problems in all chapters, with solutions to selected problems available on the book’s website; Advanced material appears in optional starred sections.
A plasma solenoid driven by an Orbital Angular Momentum laser beam
Nuter, R.; Korneev, Ph.; Thiele, I.; Tikhonchuk, V.
2018-01-01
A tens of Tesla quasi-static axial magnetic field can be produced in the interaction of a short intense laser beam carrying an Orbital Angular Momentum with an underdense plasma. Three-dimensional "Particle In Cell" simulations and analytical model demonstrate that orbital angular momentum is transfered from a tightly focused radially polarized laser beam to electrons without any dissipative effect. A theoretical model describing the balistic interaction of electrons with laser shows that par...
Orbital computed tomography: technical aspects
International Nuclear Information System (INIS)
Beck, T.J.; Rosenbaum, A.E.; Miller, N.R.
1982-01-01
Computed tomographic scanning has revolutionized the diagnosis and management of orbital disease. The best use of this methodology requires knowledge of the principles and appropriate attention to scanning protocols. Computed tomographic scanning of the orbit is a demanding technique requiring thin sections through planes precisely positioned from the topographical anatomy. Ideally, orbital CT should include both transverse axial and coronal sections: The pathological condition and its plane of growth will influence the selection of the optimal plane or section. Coronal sections may be obtained either directly or indirectly by computer reconstruction from contiguous transverse images. Sagittal or oblique sections or both also are useful and may be obtained directly or indirectly. Difficulty in patient positioning may preclude direct sagittal imaging, however. The use of intravenous contrast enhancement is not necessary as a routine technique unless a mass is identified or suspected. Where surgical resection or biopsy of a space-occupying lesion is contemplated, contrast enhancement can be valuable in assessing relative vascularity and aiding diagnostic specificity. It should be continually emphasized that CT is a powerful technology which, in orbital diagnosis, produces the highest yield when clinician and radiologist collaborate in the radiodiagnostic workup. The clinical information supplied by the referring ophthalmologist is used by the radiologist both in the selection of the appropriate techniques for investigation and in striving to achieve the most specific conclusion
Riddle, Bob
2011-01-01
Despite the temporary setback in our country's crewed space exploration program, there will continue to be missions requiring crews to orbit Earth and beyond. Under the NASA Authorization Act of 2010, NASA should have its own heavy launch rocket and crew vehicle developed by 2016. Private companies will continue to explore space, as well. At the…
Closed orbit analysis for RHIC
International Nuclear Information System (INIS)
Milutinovic, J.; Ruggiero, A.G.
1989-01-01
We examine the effects of four types of errors in the RHIC dipoles and quadrupoles on the on-momentum closed orbit in the machine. We use PATRIS both to handle statistically the effects of kick-modeled errors and to check the performance of the Fermilab correcting scheme in a framework of a more realistic modeling. On the basis of the accepted rms values of the lattice errors, we conclude that in about 40% of all studied cases the lattice must be to some extent pre-corrected in the framework of the so-called ''first turn around strategy,'' in order to get a closed orbit within the aperture limitations at all and, furthermore, for approximately 2/3 of the remaining cases we find that a single pass algorithm of the Fermilab scheme is not sufficient to bring closed orbit distortions down to acceptable levels. We have modified the scheme and have allowed repeated applications of the otherwise unchanged three bump method and in doing so we have been able to correct the orbit in a satisfactory manner. 4 refs., 2 figs., 3 tabs
DOT strategies versus orbiter strategies
Rutten, R.J.
2001-01-01
The Dutch Open Telescope is a high-resolution solar imager coming on-line at La Palma. The definition of the DOT science niche, strategies, and requirements resemble Solar Orbiter considerations and deliberations. I discuss the latter in the light of the former, and claim that multi-line observation
CONGENITAI, ORBITAL, TERATOMIA IN A
African Journals Online (AJOL)
Plastic and Reconstructive Surgery Unit, National Orthopaedic Hospital, Enugu, Nigeria. ABSTRAC"H". Congenital orbital teratomas are rare. This is a case report of an otherwise .... aspirate showed fairly cloudy, blood-tinged straw- coloured fluid with no malignant cells or organisms. Two histopathology reports of 3cm/ ...
THREE PLANETS ORBITING WOLF 1061
Energy Technology Data Exchange (ETDEWEB)
Wright, D. J.; Wittenmyer, R. A.; Tinney, C. G.; Bentley, J. S.; Zhao, Jinglin, E-mail: duncan.wright@unsw.edu.au [Department of Astronomy and Australian Centre for Astrobiology, School of Physics, University of New South Wales, NSW 2052 (Australia)
2016-02-01
We use archival HARPS spectra to detect three planets orbiting the M3 dwarf Wolf 1061 (GJ 628). We detect a 1.36 M{sub ⊕} minimum-mass planet with an orbital period P = 4.888 days (Wolf 1061b), a 4.25 M{sub ⊕} minimum-mass planet with orbital period P = 17.867 days (Wolf 1061c), and a likely 5.21 M{sub ⊕} minimum-mass planet with orbital period P = 67.274 days (Wolf 1061d). All of the planets are of sufficiently low mass that they may be rocky in nature. The 17.867 day planet falls within the habitable zone for Wolf 1061 and the 67.274 day planet falls just outside the outer boundary of the habitable zone. There are no signs of activity observed in the bisector spans, cross-correlation FWHMs, calcium H and K indices, NaD indices, or Hα indices near the planetary periods. We use custom methods to generate a cross-correlation template tailored to the star. The resulting velocities do not suffer the strong annual variation observed in the HARPS DRS velocities. This differential technique should deliver better exploitation of the archival HARPS data for the detection of planets at extremely low amplitudes.
Orbital meningioma, the Utrecht experience
Mourits, Maarten Ph.; Berkelbach van der Sprenkel, Jan Willem
2001-01-01
AIMS. 1) To evaluate epidemiological data (age, gender, initial complaints, and ophthalmic findings) of a patient cohort with a primary or secondary orbital meningioma. 2) To evaluate the clinical course of these patients. 3) To evaluate the outcome of treatment. PATIENTS AND METHODS. All
International Nuclear Information System (INIS)
Prasad, R.
1984-01-01
Two previous monographs report on investigations into the extent to which a unified field theory can satisfactorily describe physical reality. The first, Unified field Theory, showed that the paths within a non-Riemannian space are governed by eigenvalue equations. The second, Fundamental Constants, show that the field tensors satisfy sets of differential equations with solutions which represent the evolution of the fields along the paths of the space. The results from the first two monographs are used in this one to make progress on the theory of elementary particles. The five chapters are as follows - Quantum mechanics, gravitation and electromagnetism are aspects of the Unified theory; the fields inside the particle; the quadratic and linear theories; the calculation of the eigenvalues and elementary particles as stable configurations of interacting fields. It is shown that it is possible to construct an internal structure theory for elementary particles. The theory lies within the framework of Einstein's programme-to identify physical reality with a specified geometrical structure. (U.K.)
International Nuclear Information System (INIS)
Miller, David J.
1987-01-01
The Conference on Position-Sensitive Detectors held at London's University College from 7-11 September highlighted the importance and the growing applications of these precision devices in many branches of science, underlining once again the high spinoff potential for techniques developed inside particle physics
International Nuclear Information System (INIS)
Mais, H.; Ripken, G.; Wrulich, A.; Schmidt, F.
1986-02-01
After a brief description of typical applications of particle tracking in storage rings and after a short discussion of some limitations and problems related with tracking we summarize some concepts and methods developed in the qualitative theory of dynamical systems. We show how these concepts can be applied to the proton ring HERA. (orig.)
Energy Technology Data Exchange (ETDEWEB)
Miller, David J.
1987-10-15
The Conference on Position-Sensitive Detectors held at London's University College from 7-11 September highlighted the importance and the growing applications of these precision devices in many branches of science, underlining once again the high spinoff potential for techniques developed inside particle physics.
2005-01-01
While biomedicine and geoscience use grids to bring together many different sub-disciplines, particle physicists use grid computing to increase computing power and storage resources, and to access and analyze vast amounts of data collected from detectors at the world's most powerful accelerators (1 page)
Orbital roof encephalocele mimicking a destructive neoplasm.
Alsuhaibani, Adel H; Hitchon, Patrick W; Smoker, Wendy R K; Lee, Andrew G; Nerad, Jeffrey A
2011-01-01
The purpose of this case report is to report an orbital roof encephalocele mimicking a destructive orbital neoplasm. Orbital roof encephalocele is uncommon but can mimic neoplasm. One potential mechanism for the orbital roof destruction is a post-traumatic "growing orbital roof fracture." The growing fracture has been reported mostly in children but can occur in adults. Alternative potential etiologies for the encephalocele are discussed, including Gorham syndrome. Orbital roof encephalocele is uncommon in adults, and the findings can superficially resemble an orbital neoplasm. Radiographic and clinical features that might suggest the correct diagnosis include a prior history of trauma, overlying frontal lobe encephalomalacia without significant mass effect or edema, and an orbital roof defect. The "growing fracture" mechanism may be a potential explanation for the orbital roof destruction in some cases.
The globe and orbit in Laron syndrome.
Kornreich, L; Konen, O; Lilos, P; Laron, Z
2011-09-01
Patients with LS have an inborn growth hormone resistance, resulting in failure to generate IGF-1. The purpose of this study was to evaluate the size of the eye and orbit in LS. We retrospectively reviewed the MR imaging of the brain in 9 patients with LS for the following parameters: axial diameter of the globe, interzygomatic distance, perpendicular distance from the interzygomatic line to margins of the globe, medial-to-lateral diameter of the orbit at the anterior orbital rim, distance from the anterior orbital rim to the anterior globe, maximal distance between the medial walls of the orbits, lateral orbital wall angle, lateral orbital wall length, and mediolateral thickness of the intraorbital fat in the most cranial image of the orbit. All measurements were made bilaterally. Twenty patients referred for MR imaging for unrelated reasons served as control subjects. Compared with the control group, the patients with LS had a significantly smaller maximal globe diameter and shallower but wider orbits due to a shorter lateral wall, a smaller medial distance between the orbits, and a larger angle of the orbit. The ratio between the most anterior orbital diameter and the globe was greater than that in controls. The position of the globe was more anterior in relation to the interzygomatic line. Shallow and wide orbits and small globes relative to orbital size are seen in LS and may be secondary to IGF-1 deficiency.
Macroscopic spin-orbit coupling in non-uniform magnetic fields
Energy Technology Data Exchange (ETDEWEB)
Tabat, N.; Edelman, H. S.; Song, D. [Semaphore Scientific, Inc., St. Cloud, Minnesota 56301 (United States); Vogt, T. [Department of Electrical and Computer Engineering, St. Cloud State University, St. Cloud, Minnesota 56301 (United States)
2015-03-02
Translational dynamics of aggregated magnetic nano-particles placed in a rotating external magnetic field is described. It is observed and explained that aggregates that spin within a radially decreasing field strength must execute an orbital motion of their center of mass in a sense that counters their spin rotation. This orbital motion is tightly coupled to the spin dynamics of the aggregates. An analytical model for the canonical variables describing the orbital motion is derived and shown to be in good agreement with the measured values.
Macroscopic spin-orbit coupling in non-uniform magnetic fields
International Nuclear Information System (INIS)
Tabat, N.; Edelman, H. S.; Song, D.; Vogt, T.
2015-01-01
Translational dynamics of aggregated magnetic nano-particles placed in a rotating external magnetic field is described. It is observed and explained that aggregates that spin within a radially decreasing field strength must execute an orbital motion of their center of mass in a sense that counters their spin rotation. This orbital motion is tightly coupled to the spin dynamics of the aggregates. An analytical model for the canonical variables describing the orbital motion is derived and shown to be in good agreement with the measured values
Broadening of ICRH produced fast ion profiles due to orbit effects
International Nuclear Information System (INIS)
Eriksson, L.-G.; Porcelli, F.
1991-01-01
In the JET tokamak, minority ions accelerated by ICRH reach energies in the MeV range. Near the plasma magnetic axis, the standard trapped particle ''banana'' orbit is distorted into a ''potato'' or ''fat banana'' orbit. The zero banana width approximation which is used in most Fokker-Planck calculations of velocity distributions of resonating ions is often not valid in JET. The inclusion of finite banana width effects will, in general, lead to a lowering of the averaged tail energy and a broadening of pressure profiles, power transfer profiles etc. A model for calculating orbit broadened profiles is presented. (Author)
International Nuclear Information System (INIS)
Cobb, J.W.; Leboeuf, J.N.
1994-01-01
The authors present a particle algorithm to extend simulation capabilities for plasma based materials processing reactors. The orbit integrator uses a syncopated leap-frog algorithm in cylindrical coordinates, which maintains second order accuracy, and minimizes computational complexity. Plasma source terms are accumulated orbit consistently directly in the frequency and azimuthal mode domains. Finally they discuss the numerical analysis of this algorithm. Orbit consistency greatly reduces the computational cost for a given level of precision. The computational cost is independent of the degree of time scale separation
Subdecoherence time generation and detection of orbital entanglement in quantum dots.
Brange, F; Malkoc, O; Samuelsson, P
2015-05-01
Recent experiments have demonstrated subdecoherence time control of individual single-electron orbital qubits. Here we propose a quantum-dot-based scheme for generation and detection of pairs of orbitally entangled electrons on a time scale much shorter than the decoherence time. The electrons are entangled, via two-particle interference, and transferred to the detectors during a single cotunneling event, making the scheme insensitive to charge noise. For sufficiently long detector dot lifetimes, cross-correlation detection of the dot charges can be performed with real-time counting techniques, providing for an unambiguous short-time Bell inequality test of orbital entanglement.
Manipulation and application of orbital ordering
International Nuclear Information System (INIS)
Sheng Zhigao; Sun Yuping
2014-01-01
Under certain conditions, the orbits of the outmost shell electrons in strong correlated materials can be localized in order, which gives birth to so-called orbital ordering. During the construction or destruction of the orbital ordering, strongly correlated materials show fruitful quantum critical phenomena with great potential for future applications. We first present the mechanism for the construction of orbital ordering. Then, some physical properties associated with orbits are discussed. Finally, we emphasize the key points and progress in the research of orbital ordering controlling. (authors)
Energetic Particles Dynamics in Mercury's Magnetosphere
Walsh, Brian M.; Ryou, A.S.; Sibeck, D. G.; Alexeev, I. I.
2013-01-01
We investigate the drift paths of energetic particles in Mercury's magnetosphere by tracing their motion through a model magnetic field. Test particle simulations solving the full Lorentz force show a quasi-trapped energetic particle population that gradient and curvature drift around the planet via "Shabansky" orbits, passing though high latitudes in the compressed dayside by equatorial latitudes on the nightside. Due to their large gyroradii, energetic H+ and Na+ ions will typically collide with the planet or the magnetopause and will not be able to complete a full drift orbit. These simulations provide direct comparison for recent spacecraft measurements from MESSENGER. Mercury's offset dipole results in an asymmetric loss cone and therefore an asymmetry in particle precipitation with more particles precipitating in the southern hemisphere. Since the planet lacks an atmosphere, precipitating particles will collide directly with the surface of the planet. The incident charged particles can kick up neutrals from the surface and have implications for the formation of the exosphere and weathering of the surface
Numerical evaluation of high energy particle effects in magnetohydrodynamics
International Nuclear Information System (INIS)
White, R.B.; Wu, Y.
1994-03-01
The interaction of high energy ions with magnetohydrodynamic modes is analyzed. A numerical code is developed which evaluates the contribution of the high energy particles to mode stability using orbit averaging of motion in either analytic or numerically generated equilibria through Hamiltonian guiding center equations. A dispersion relation is then used to evaluate the effect of the particles on the linear mode. Generic behavior of the solutions of the dispersion relation is discussed and dominant contributions of different components of the particle distribution function are identified. Numerical convergence of Monte-Carlo simulations is analyzed. The resulting code ORBIT provides an accurate means of comparing experimental results with the predictions of kinetic magnetohydrodynamics. The method can be extended to include self consistent modification of the particle orbits by the mode, and hence the full nonlinear dynamics of the coupled system
Finite Orbit Width Features in the CQL3D Code
Energy Technology Data Exchange (ETDEWEB)
Petrov, Y. V.; Harvey, R., E-mail: petrov@compxco.com [CompX, Del Mar (United States)
2012-09-15
Full text: The CQL3D Fokker-Planck equation solver is being upgraded to allow for the Finite-Orbit- Width (FOW) capabilities, which will provide an accurate description for a neoclassical transport, losses to the walls, and transfer of particles, momentum, and heat to the scrape-off layer. Two different options are discussed for implementing the FOW capabilities. In one option, the Fokker-Planck equation is solved for the distribution function of orbits centered around given flux surface; in the other, the equation is solved for the local distribution function at the outer-most point of flux surface at the midplane. Both options use a fast lookup table that allows characterization of orbits without actually tracing them. The lookup table, in effect, performs mapping from the Constants-Of-Motion space onto the (R{sub o}, u{sub o}, {theta}{sub o}) computational space on the midplane. The FOW modifications have been implemented for the formations of neutral beam source, RF quasilinear diffusion operator, particle diagnostics and collisional operator, and internal boundary conditions are being refined. Initial test runs show that in general, the FOW modifications result in a broader profiles of power absorption and RF-driven current, and accurate description of the loss cone. (author)
DRAGONS - A Micrometeoroid and Orbital Debris Impact Sensor
Liou, J. -C.; Corsaro, R.; Giovane, F.; Anderson, C.; Sadilek, A.; Burchell, M.; Hamilton, J.
2015-01-01
The Debris Resistive/Acoustic Grid Orbital Navy-NASA Sensor (DRAGONS) is intended to be a large area impact sensor for in situ measurements of micrometeoroids and orbital debris (MMOD) in the millimeter or smaller size regime. These MMOD particles are too small to be detected by ground-based radars and optical telescopes, but are still large enough to be a serious safety concern for human space activities and robotic missions in the low Earth orbit (LEO) region. The nominal detection area of a DRAGONS unit is 1 m2, consisting of several independently operated panels. The approach of the DRAGONS design is to combine different particle impact detection principles to maximize information that can be extracted from detected events. After more than 10 years of concept and technology development, a 1 m2 DRAGONS system has been selected for deployment on the International Space Station (ISS) in August 2016. The project team achieved a major milestone when the Preliminary Design Review (PDR) was completed in May 2015. Once deployed on the ISS, this multi-year mission will provide a unique opportunity to demonstrate the MMOD detection capability of the DRAGONS technologies and to collect data to better define the small MMOD environment at the ISS altitude.
Image-charge-induced localization of molecular orbitals at metal-molecule interfaces
DEFF Research Database (Denmark)
Strange, M.; Thygesen, K. S.
2012-01-01
Quasiparticle (QP) wave functions, also known as Dyson orbitals, extend the concept of single-particle states to interacting electron systems. Here we employ many-body perturbation theory in the GW approximation to calculate the QP wave functions for a semiempirical model describing a pi-conjugat......Quasiparticle (QP) wave functions, also known as Dyson orbitals, extend the concept of single-particle states to interacting electron systems. Here we employ many-body perturbation theory in the GW approximation to calculate the QP wave functions for a semiempirical model describing a pi...
Orbital angular momentum of a high-order Bessel light beam
International Nuclear Information System (INIS)
Volke-Sepulveda, K; Garces-Chavez, V; Chavez-Cerda, S; Arlt, J; Dholakia, K
2002-01-01
The orbital angular momentum density of Bessel beams is calculated explicitly within a rigorous vectorial treatment. This allows us to investigate some aspects that have not been analysed previously, such as the angular momentum content of azimuthally and radially polarized beams. Furthermore, we demonstrate experimentally the mechanical transfer of orbital angular momentum to trapped particles in optical tweezers using a high-order Bessel beam. We set transparent particles of known dimensions into rotation, where the sense of rotation can be reversed by changing the sign of the singularity. Quantitative results are obtained for rotation rates. This paper's animations are available from the Multimedia Enhancements page
ORBIT FEEDBACK CONTROL FOR THE LHC Prototyping at the SPS
Steinhagen, Ralph J
2004-01-01
The Large Hadron Collider (LHC) is the next generation proton collider that is presently built at CERN. The LHC will be installed in the former LEP (Large Electron Positron Collider) tunnel. The presence of a high intensity beam in an environment of cryogenic magnets requires an excellent control of particle losses from the beam. Eventually the performance of the LHC may be limited by the ability to control the beam losses. The performance of the LHC cleaning system depends critically on the beam position stability. Ground motion, field and alignment imperfections and beam manipulations may cause orbit movements. The role of the future LHC Orbit Feedback System is the minimisation of closed orbit perturbations by periodically measuring and steering the transverse beam position back to its reference position. This diploma thesis focuses on the design and prototyping of an orbit feedback system at the SPS. The design is based on a separation of the steering problem into space and time. While the correction in s...
Degond, Pierre; Tadmor, Eitan
2017-01-01
This volume collects ten surveys on the modeling, simulation, and applications of active particles using methods ranging from mathematical kinetic theory to nonequilibrium statistical mechanics. The contributing authors are leading experts working in this challenging field, and each of their chapters provides a review of the most recent results in their areas and looks ahead to future research directions. The approaches to studying active matter are presented here from many different perspectives, such as individual-based models, evolutionary games, Brownian motion, and continuum theories, as well as various combinations of these. Applications covered include biological network formation and network theory; opinion formation and social systems; control theory of sparse systems; theory and applications of mean field games; population learning; dynamics of flocking systems; vehicular traffic flow; and stochastic particles and mean field approximation. Mathematicians and other members of the scientific commu...
International Nuclear Information System (INIS)
Merwin, S.E.; Moeller, M.P.
1989-01-01
Nuclear Regulatory Commission (NRC) licensees are required to assess the dose to skin from a hot particle contamination event at a depth of skin of7mg/cm 2 over an area of 1 cm 2 and compare the value to the current dose limit for the skin. Although the resulting number is interesting from a comparative standpoint and can be used to predict local skin reactions, comparison of the number to existing limits based on uniform exposures is inappropriate. Most incidents that can be classified as overexposures based on this interpretation of dose actually have no effect on the health of the worker. As a result, resources are expended to reduce the likelihood that an overexposure event will occur when they could be directed toward eliminating the cause of the problem or enhancing existing programs such as contamination control. Furthermore, from a risk standpoint, this practice is not ALARA because some workers receive whole body doses in order to minimize the occurrence of hot particle skin contaminations. In this paper the authors suggest an alternative approach to controlling hot particle exposures
Energy Technology Data Exchange (ETDEWEB)
Janches, D.; Swarnalingam, N. [Space Weather Laboratory, Mail Code 674, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Close, S. [Space Environment and Satellite Systems Laboratory, Department of Aeronautics and Astronautics, Stanford University, Palo Alto, CA (United States); Hormaechea, J. L. [Estacion Astronomica Rio Grande, Rio Grande, Tierra del Fuego (Argentina); Murphy, A.; O’Connor, D.; Vandepeer, B.; Fuller, B. [Genesis Software Pty Ltd, Adelaide (Australia); Fritts, D. C. [GATS Inc., Boulder CO (United States); Brunini, C., E-mail: diego.janches@nasa.gov, E-mail: nimalan.swarnalingam@nasa.gov, E-mail: sigridc@stanford.edu, E-mail: jlhormaechea@untdf.edu.ar, E-mail: amurphy@gsoft.com.au, E-mail: doconnor@gsoft.com.au, E-mail: bvandepe@gsoft.com.au, E-mail: bfuller@gsoft.com.au, E-mail: dave@gats-inc.com, E-mail: claudiobrunini@yahoo.com [Departmento de Astronomia y Geofísica, Universidad Nacional de La Plata, La Plata (Argentina)
2015-08-10
We present an initial survey in the southern sky of the sporadic meteoroid orbital environment obtained with the Southern Argentina Agile MEteor Radar (SAAMER) Orbital System (OS), in which over three-quarters of a million orbits of dust particles were determined from 2012 January through 2015 April. SAAMER-OS is located at the southernmost tip of Argentina and is currently the only operational radar with orbit determination capability providing continuous observations of the southern hemisphere. Distributions of the observed meteoroid speed, radiant, and heliocentric orbital parameters are presented, as well as those corrected by the observational biases associated with the SAAMER-OS operating parameters. The results are compared with those reported by three previous surveys performed with the Harvard Radio Meteor Project, the Advanced Meteor Orbit Radar, and the Canadian Meteor Orbit Radar, and they are in agreement with these previous studies. Weighted distributions for meteoroids above the thresholds for meteor trail electron line density, meteoroid mass, and meteoroid kinetic energy are also considered. Finally, the minimum line density and kinetic energy weighting factors are found to be very suitable for meteroid applications. The outcomes of this work show that, given SAAMER’s location, the system is ideal for providing crucial data to continuously study the South Toroidal and South Apex sporadic meteoroid apparent sources.
Janches, D.; Close, S.; Hormaechea, J. L.; Swarnalingam, N.; Murphy, A.; O'Connor, D.; Vandepeer, B.; Fuller, B.; Fritts, D. C.; Brunini, C.
2015-01-01
We present an initial survey in the southern sky of the sporadic meteoroid orbital environment obtained with the Southern Argentina Agile MEteor Radar (SAAMER) Orbital System (OS), in which over three-quarters of a million orbits of dust particles were determined from 2012 January through 2015 April. SAAMER-OS is located at the southernmost tip of Argentina and is currently the only operational radar with orbit determination capability providing continuous observations of the southern hemisphere. Distributions of the observed meteoroid speed, radiant, and heliocentric orbital parameters are presented, as well as those corrected by the observational biases associated with the SAAMER-OS operating parameters. The results are compared with those reported by three previous surveys performed with the Harvard Radio Meteor Project, the Advanced Meteor Orbit Radar, and the Canadian Meteor Orbit Radar, and they are in agreement with these previous studies. Weighted distributions for meteoroids above the thresholds for meteor trail electron line density, meteoroid mass, and meteoroid kinetic energy are also considered. Finally, the minimum line density and kinetic energy weighting factors are found to be very suitable for meteoroid applications. The outcomes of this work show that, given SAAMERs location, the system is ideal for providing crucial data to continuously study the South Toroidal and South Apex sporadic meteoroid apparent sources.
Kelley, H. J.; Cliff, E. M.; Lutze, F. H.
1981-01-01
Maneuvers available to a spacecraft having sufficient propellant to escape an antisatellite satellite (ASAT) attack are examined. The ASAT and the evading spacecraft are regarded as being in circular orbits, and equations of motion are developed for the ASAT to commence a two-impulse maneuver sequence. The ASAT employs thrust impulses which yield a minimum-time-to-rendezvous, considering available fuel. Optimal evasion is shown to involve only in-plane maneuvers, and begins as soon as the ASAT launch information is gathered and thrust activation can be initiated. A closest approach, along with a maximum evasion by the target spacecraft, is calculated to be 14,400 ft. Further research to account for ASATs in parking orbit and for generalization of a continuous control-modeled differential game is indicated.
International Nuclear Information System (INIS)
Sanchez-Chopitea, L.; Emma, P.; Van Olst, D.
1991-05-01
Beam orbits in the SLC are monitored in real time and the data is stored for future trend and correlation analysis. A background process acquires Beam Position Monitor (BPM) and Toroid data on a periodic basis and saves the general quantities such as orbit RMS and beam intensity in addition to the individual readings. Some of this data is archived by the SLC History Buffer facility and the rest is saved in files for later analysis. This has permitted the tracing of interaction point instabilities to specific devices as far away as the damping rings. In addition, the data is displayed for the operators both in summary and in full form. The different displays can be configured from the control consoles. 2 refs., 5 figs
[Orbital decompression in Grave's ophtalmopathy].
Longueville, E
2010-01-01
Graves disease orbitopathy is a complex progressive inflammatory disease. Medical treatment remains in all cases the proposed treatment of choice. Surgical treatment by bone decompression can be considered as an emergency mainly in cases of optic neuropathy or ocular hypertension not being controlled medically or in post-traumatic exophthalmos stage. Emergency bone decompression eliminates compression or stretching of the optic nerve allowing visual recovery. The uncontrolled ocular hypertension will benefit from decompression. The normalization of intraocular pressure may be obtained by this surgery or if needed by the use of postoperative antiglaucoma drops or even filtration surgery. In all operated cases, the IOP was normalized with an average decrease of 7.71 mmHg and a cessation of eye drops in 3/7 cases. Regarding sequelae, our therapeutic strategy involves consecutively surgery of the orbit, extraocular muscles and eyelids. The orbital expansion gives excellent results on the cosmetic level and facilitates the implementation of subsequent actions.
Robustness analysis method for orbit control
Zhang, Jingrui; Yang, Keying; Qi, Rui; Zhao, Shuge; Li, Yanyan
2017-08-01
Satellite orbits require periodical maintenance due to the presence of perturbations. However, random errors caused by inaccurate orbit determination and thrust implementation may lead to failure of the orbit control strategy. Therefore, it is necessary to analyze the robustness of the orbit control methods. Feasible strategies which are tolerant to errors of a certain magnitude can be developed to perform reliable orbit control for the satellite. In this paper, first, the orbital dynamic model is formulated by Gauss' form of the planetary equation using the mean orbit elements; the atmospheric drag and the Earth's non-spherical perturbations are taken into consideration in this model. Second, an impulsive control strategy employing the differential correction algorithm is developed to maintain the satellite trajectory parameters in given ranges. Finally, the robustness of the impulsive control method is analyzed through Monte Carlo simulations while taking orbit determination error and thrust error into account.
Management of ocular, orbital, and adnexal trauma
International Nuclear Information System (INIS)
Spoor, T.C.; Nesi, F.A.
1988-01-01
This book contains 20 chapters. Some of the chapter titles are: The Ruptured Globe: Primary Care; Corneal Trauma, Endophthalmitis; Antibiotic Usage; Radiology of Orbital Trauma; Maxillofacial Fractures; Orbital Infections; and Basic Management of Soft Tissue Injury
Composite particles and symplectic (Semi-) groups
International Nuclear Information System (INIS)
Kramer, P.
1978-01-01
Nuclear composits particle dynamics is intimately related to the fermion character of nucleons. This property is implemented via the permutational structure of nuclear states, leading to the concept of exchange and to the quantum number of the orbital partition. We review Weyl operators and representations of linear canonical transformations in Bargmann Hilbert space. In section 4 we use canonical transformations to describe the general n-body dynamics. In section 5 we derive the composite particle dynamics and discuss an algorithm to obtain the interaction of composite particles whose constituents are assumed to be in harmonic oscillator states. As a first example we treat in section 6 composite particles with unexcited internal oscillator states. In section 7 we deal with composite particles of internal oscillator shell configurations. (orig.) [de
Dynamique des orbites fortement elliptiques
Lion , Guillaume
2013-01-01
Most of the orbits of artificial satellites around the Earth have relatively low eccentricities. The calculation of their trajectories is very well under control, either by means of numerical methods when it comes to focus on accuracy and comparing observations, or either through analytical or semi-analytical theories to optimize the speed of calculations. This second category is used, in particular, for computing many long-term trajectories that could help to ensure the security and safety o...
Orbital Volumetry in Graves' Orbitopathy
DEFF Research Database (Denmark)
Al-Bakri, Moug; Rasmussen, Åse Krogh; Thomsen, Carsten
2014-01-01
were retrospectively analyzed. Thirteen patients imaged for unilateral orbital fractures served as controls. Results. The retrobulbar muscle volume was 2.1 ± 0.5 cm(3) (mean ± SD) in controls, 4.3 ± 1.5 cm(3) in GO without DON, and 4.7 ± 1.7 cm(3) in GO with DON. The retrobulbar fat volume was 5.4 ± 1...
A new kinematical definition of orbital eccentricity
Directory of Open Access Journals (Sweden)
Ninković S.
2009-01-01
Full Text Available A new concept of orbital eccentricity is given. The dimensionless quantities proposed in the present paper to serve as orbital eccentricities have a kinematical nature. The purpose is to use them in describing the motion for the case of three-dimensional orbits. A comparison done for nearly planar orbits shows that the values of the eccentricities proposed here do not differ significantly from those corresponding to the eccentricities of geometric nature usually applied.
An Ontological Architecture for Orbital Debris Data
Rovetto, Robert J.
2017-01-01
The orbital debris problem presents an opportunity for inter-agency and international cooperation toward the mutually beneficial goals of debris prevention, mitigation, remediation, and improved space situational awareness (SSA). Achieving these goals requires sharing orbital debris and other SSA data. Toward this, I present an ontological architecture for the orbital debris domain, taking steps in the creation of an orbital debris ontology (ODO). The purpose of this ontological system is to ...
Algorithms for orbit control on SPEAR
International Nuclear Information System (INIS)
Corbett, J.; Keeley, D.; Hettel, R.; Linscott, I.; Sebek, J.
1994-06-01
A global orbit feedback system has been installed on SPEAR to help stabilize the position of the photon beams. The orbit control algorithms depend on either harmonic reconstruction of the orbit or eigenvector decomposition. The orbit motion is corrected by dipole corrector kicks determined from the inverse corrector-to-bpm response matrix. This paper outlines features of these control algorithms as applied to SPEAR
Commissioning of the APS real-time orbit feedback system
International Nuclear Information System (INIS)
Carwardine, J.; Decker, G.; Evans, K. Jr.; Hillman, A.; Lenkszus, F.; Merl, R.; Pietryla, A.
1997-01-01
A unified global and local closed-orbit feedback system has been implemented at the Advanced Photon Source in order to stabilize both particle and photon beams. Beam stability requirements in the band up to 50 Hz are 17 microm in the horizontal plane and 4.4 microm vertically. Orbit feedback algorithms are implemented digitally using multiple digital signal processors, with computing power distributed in 20 VME crates around the storage ring. Each crate communicates with all others via a fast reflective memory network. The system has access to 320 rf beam position monitors together with x-ray beam position monitors in both insertion device and bending magnet beamlines. Up to 317 corrector magnets are available to the system. The global system reduces horizontal rms beam motion at the x-ray source points by more than a factor of two in the frequency band from 10 mHz to 50 Hz
GOC: General Orbit Code. [In FORTRAN for IBM 360
Energy Technology Data Exchange (ETDEWEB)
Maddox, L.B.; McNeilly, G.S.
1979-08-01
GOC (General Orbit Code) is a versatile program which will perform a variety of calculations relevant to isochronous cyclotron design studies. In addition to the usual calculations of interest (e.g., equilibrium and accelerated orbits, focusing frequencies, field isochronization, etc.), GOC has a number of options to calculate injections with a charge change. GOC provides both printed and plotted output, and will follow groups of particles to allow determination of finite-beam properties. An interactive PDP-10 program called GIP, which prepares input data for GOC, is available. GIP is a very easy and convenient way to prepare complicated input data for GOC. Enclosed with this report are several microfiche containing source listings of GOC and other related routines and the printed output from a multiple-option GOC run.
Gate-dependent orbital magnetic moments in carbon nanotubes
DEFF Research Database (Denmark)
Jespersen, Thomas Sand; Grove-Rasmussen, Kasper; Flensberg, Karsten
2011-01-01
We investigate how the orbital magnetic moments of electron and hole states in a carbon nanotube quantum dot depend on the number of carriers on the dot. Low temperature transport measurements are carried out in a setup where the device can be rotated in an applied magnetic field, thus enabling...... accurate alignment with the nanotube axis. The field dependence of the level structure is measured by excited state spectroscopy and excellent correspondence with a single-particle calculation is found. In agreement with band structure calculations we find a decrease of the orbital magnetic moment...... with increasing electron or hole occupation of the dot, with a scale given by the band gap of the nanotube....
Traumatic orbital encephalocele: Presentation and imaging.
Wei, Leslie A; Kennedy, Tabassum A; Paul, Sean; Wells, Timothy S; Griepentrog, Greg J; Lucarelli, Mark J
2016-01-01
Traumatic orbital encephalocele is a rare but severe complication of orbital roof fractures. We describe 3 cases of orbital encephalocele due to trauma in children. Retrospective case series from the University of Wisconsin - Madison and Medical College of Wisconsin. Three cases of traumatic orbital encephalocele in pediatric patients were found. The mechanism of injury was motor vehicle accident in 2 patients and accidental self-inflicted gunshot wound in 1 patient. All 3 patients sustained orbital roof fractures (4 mm to 19 mm in width) and frontal lobe contusions with high intracranial pressure. A key finding in all 3 cases was progression of proptosis and globe displacement 4 to 11 days after initial injury. On initial CT, all were diagnosed with extraconal hemorrhage adjacent to the roof fractures, with subsequent enlargement of the mass and eventual diagnosis of encephalocele. Orbital encephalocele is a severe and sight-threatening complication of orbital roof fractures. Post-traumatic orbital encephalocele can be challenging to diagnose on CT as patients with this condition often have associated orbital and intracranial hematoma, which can be difficult to distinguish from herniated brain tissue. When there is a high index of suspicion for encephalocele, an MRI of the orbits and brain with contrast should be obtained for additional characterization. Imaging signs that should raise suspicion for traumatic orbital encephalocele include an enlarging heterogeneous orbital mass in conjunction with a roof fracture and/or widening fracture segments.
[1012.5676] The Exoplanet Orbit Database
: The Exoplanet Orbit Database Authors: Jason T Wright, Onsi Fakhouri, Geoffrey W. Marcy, Eunkyu Han present a database of well determined orbital parameters of exoplanets. This database comprises parameters, and the method used for the planets discovery. This Exoplanet Orbit Database includes all planets
The orbital record in stratigraphy
Fischer, Alfred G.
1992-01-01
Orbital signals are being discovered in pre-Pleistocene sediments. Due to their hierarchical nature these cycle patterns are complex, and the imprecision of geochronology generally makes the assignment of stratigraphic cycles to specific orbital cycles uncertain, but in sequences such as the limnic Newark Group under study by Olsen and pelagic Cretaceous sequence worked on by our Italo-American group the relative frequencies yield a definitive match to the Milankovitch hierarchy. Due to the multiple ways in which climate impinges on depositional systems, the orbital signals are recorded in a multiplicity of parameters, and affect different sedimentary facies in different ways. In platform carbonates, for example, the chief effect is via sea-level variations (possibly tied to fluctuating ice volume), resulting in cycles of emergence and submergence. In limnic systems it finds its most dramatic expression in alternations of lake and playa conditions. Biogenic pelagic oozes such as chalks and the limestones derived from them display variations in the carbonate supplied by planktonic organisms such as coccolithophores and foraminifera, and also record variations in the aeration of bottom waters. Whereas early studies of stratigraphic cyclicity relied mainly on bedding variations visible in the field, present studies are supplementing these with instrumental scans of geochemical, paleontological, and geophysical parameters which yield quantitative curves amenable to time-series analysis; such analysis is, however, limited by problems of distorted time-scales. My own work has been largely concentrated on pelagic systems. In these, the sensitivity of pelagic organisms to climatic-oceanic changes, combined with the sensitivity of botton life to changes in oxygen availability (commonly much more restricted in the Past than now) has left cyclic patterns related to orbital forcing. These systems are further attractive because (1) they tend to offer depositional continuity
Orbit effects on impurity transport in a rotating plasma
International Nuclear Information System (INIS)
Wong, K.L.; Cheng, C.Z.
1988-01-01
In 1985, very high ion temperature plasmas were first produced in TFTR with co-injecting neutral beams in low current, low density plasmas. This mode of operation is called the energetic ion mode in which the plasma rotates at very high speed. It was found that heavy impurities injected into these plasmas diffused out very quickly. In this paper, the authors calculate the impurity ion orbits in a rotating tokamak plasma based on the equation of motion in the frame that rotates with the plasma. It is shown that heavy particles in a rotating plasma can drift away from magnetic surfaces significantly faster. Particle orbits near the surface of a rotating tokamak are also analyzed. During impurity injection experiments, freshly ionized impurities near the plasma surface are essentially stationary in the laboratory frame and they are counter-rotating in the plasma frame with co-beam injection. The results are substantiated by numeral particle simulation. The computer code follows the impurity guiding center positions by integrating the equation of motion with the second order predictor-corrector method
Parameningeal rhabdomyosarcoma (including the orbit): results of orbital irradiation
International Nuclear Information System (INIS)
Jereb, B.; Haik, B.G.; Ong, R.; Ghavimi, F.
1985-01-01
Twenty-three patients with parameningeal (including orbital rhabdomyosarcoma (RMS)) were treated at Memorial Sloan-Kettering Cancer Center (MSKCC) between July 1971 and January 1983. Twenty were children with a mean age of 6 and 3 were adults. In 6 patients, the primary tumor was from the orbit, whereas the remaining 17 had other parameningeal primary sites. The tumors were in a very progressive local stage, with extensive destruction of the facial bones in 19 patients. Eight patients were treated with T2 chemotherapy protocol and 15 received T6. Seven patients received 5,000 to 7,200 rad delivered to the primary tumor in 11-16 weeks, 15 patients received between 4,500 to 5,000 rad in 4-7 weeks, and 1 patient received 3,000 rad in 3 weeks for residual microscopic disease following surgery. Two patients were treated with radiation to the whole brain; no patients received radiation of the whole central nervous axis (CNA). Fifteen of the 23 patients (65%) are alive and well with a medical follow-up time of 5 years. Two patients died of therapeutic complications and six died of tumor spread. In five patients, involvement of the central nervous system (CNS) was the cause of death. The prognosis of orbital RMS with parameningeal involvement is no better than in other tumors of parameningeal sites. In those patients who had impaired vision because of optic nerve damage prior to treatment, the vision did not improve following treatment. There was no impaired vision seen due to radiation damage of eye structures except in the lens
Energy Technology Data Exchange (ETDEWEB)
Khare, A.
1980-07-01
Current state of art in the discovery of new elementary particles is reviewed. At present, quarks and mesons are accepted as the basic constituents of matter. The charmonium model (canti-c system), and the 'open charm' are discussed. Explanations are offered for the recent discovery of the heavy lepton tau. Quark states such as the beauty and taste are also dealt with at length. The properties of the tanti-t bound system are speculated. It is concluded that the understanding of canti-c and banti-b families is facilitated by the assumption of the quarkonium model. Implications at the astrophysical level are indicated.
Similarity in Bilateral Isolated Internal Orbital Fractures.
Chen, Hung-Chang; Cox, Jacob T; Sanyal, Abanti; Mahoney, Nicholas R
2018-04-13
In evaluating patients sustaining bilateral isolated internal orbital fractures, the authors have observed both similar fracture locations and also similar expansion of orbital volumes. In this study, we aim to investigate if there is a propensity for the 2 orbits to fracture in symmetrically similar patterns when sustaining similar trauma. A retrospective chart review was performed studying all cases at our institution of bilateral isolated internal orbital fractures involving the medial wall and/or the floor at the time of presentation. The similarity of the bilateral fracture locations was evaluated using the Fisher's exact test. The bilateral expanded orbital volumes were analyzed using the Wilcoxon signed-rank test to assess for orbital volume similarity. Twenty-four patients with bilateral internal orbital fractures were analyzed for fracture location similarity. Seventeen patients (70.8%) had 100% concordance in the orbital subregion fractured, and the association between the right and the left orbital fracture subregion locations was statistically significant (P < 0.0001). Fifteen patients were analyzed for orbital volume similarity. The average orbital cavity volume was 31.2 ± 3.8 cm on the right and 32.0 ± 3.7 cm on the left. There was a statistically significant difference between right and left orbital cavity volumes (P = 0.0026). The data from this study suggest that an individual who suffers isolated bilateral internal orbital fractures has a statistically significant similarity in the location of their orbital fractures. However, there does not appear to be statistically significant similarity in the expansion of the orbital volumes in these patients.
Analysis of orbitally excited B-mesons
Albrecht, Zoltan; Quast, Gunter
2003-01-01
This thesis reports on the study of orbitally excited B** mesons in DELPHI b-events taken in the years 1994 to 2000 with the DELPHI detector at the LEP collider. The analyses presented represent the result of applying much improved and extended techniques of spectroscopy since the first DELPHI publication in 1995. A major improvement has occurred in the area of particle identification, where a neural network approach has been implemented in the DELPHI software package. Developments in the area of neural networks have led to much improved enrichment of the excited B states. The Bˆ{**} neural networks identify, on a track-by-track basis, the decay pion/kaon originating from the Bˆ{**} decay, suppressing background and keeping signal events in an efficient way. To improve detector resolution, a further application of neural networks has been applied to reconstruct the underlying Q-value. The corresponding network gives a correction on existing measurements of the Q-value in the form of a probability density fu...
Radiation measurements on the Mir Orbital Station
International Nuclear Information System (INIS)
Badhwar, G.D.; Atwell, W.; Reitz, G.; Beaujean, R.; Heinrich, W.
2002-01-01
Radiation measurements made onboard the MIR Orbital Station have spanned nearly a decade and covered two solar cycles, including one of the largest solar particle events, one of the largest magnetic storms, and a mean solar radio flux level reaching 250x10 4 Jansky that has been observed in the last 40 years. The cosmonaut absorbed dose rates varied from about 450 μGy day -1 during solar minimum to approximately half this value during the last solar maximum. There is a factor of about two in dose rate within a given module, and a similar variation from module to module. The average radiation quality factor during solar minimum, using the ICRP-26 definition, was about 2.4. The drift of the South Atlantic Anomaly was measured to be 6.0±0.5 deg. W, and 1.6±0.5 deg. N. These measurements are of direct applicability to the International Space Station. This paper represents a comprehensive review of Mir Space Station radiation data available from a variety of sources
Behavior of orbits of two coupled oscillators
International Nuclear Information System (INIS)
Greene, J.M.
1985-01-01
There has been very considerable progress in the past few years on the theory of two conservative, coupled, nonlinear oscillators. This work also applies to many equivalent systems, so it has applications to particle containment and heating, for example, and wherever else in plasma physics that the validity of adiabatic invariants is a matter of concern. A general problem of this class has a solution that is so complicated that it is impossible to find an expression for the state of the system that is valid for all time. However, recent results are making it possible to determine the next most useful type of information. This is the asymptotic behavior of individual orbits in the limit of very long times. This is just the information that is desired in many situations. For example, it determines the stability of the motion. The key to our present understanding is renormalization. The present state of the art has been described in Robert Mackay's thesis, for which this is an advertisement
Synchronization of finite-size particles by a traveling wave in a cylindrical flow
Melnikov, D. E.; Pushkin, D. O.; Shevtsova, V. M.
2013-09-01
Motion of small finite-size particles suspended in a cylindrical thermocapillary flow with an azimuthally traveling wave is studied experimentally and numerically. At certain flow regimes the particles spontaneously align in dynamic accumulation structures (PAS) of spiral shape. We find that long-time trajectories of individual particles in this flow fall into three basic categories that can be described, borrowing the dynamical systems terminology, as the stable periodic, the quasiperiodic, and the quasistable periodic orbits. Besides these basic types of orbits, we observe the "doubled" periodic orbits and shuttle-like particle trajectories. We find that ensembles of particles having periodic orbits give rise to one-dimensional spiral PAS, while ensembles of particles having quasiperiodic orbits form two-dimensional PAS of toroidal shape. We expound the reasons why these types of orbits and the emergence of the corresponding accumulation structures should naturally be anticipated based on the phase locking theory of PAS formation. We give a further discussion of PAS features, such as the finite thickness of PAS spirals and the probable scenarios of the spiral PAS destruction. Finally, in numerical simulations of inertial particles we observe formation of the spiral structures corresponding to the 3:1 "resonance" between the particle turnover frequency and the wave oscillations frequency, thus confirming another prediction of the phase locking theory. In view of the generality of the arguments involved, we expect the importance of this structure-forming mechanism to go far beyond the realm of the laboratory-friendly thermocapillary flows.
Orbits in weak and strong bars
Contopoulos, George
1980-01-01
The authors study the plane orbits in simple bar models embedded in an axisymmetric background when the bar density is about 1% (weak), 10% (intermediate) or 100% (strong bar) of the axisymmetric density. Most orbits follow the stable periodic orbits. The basic families of periodic orbits are described. In weak bars with two Inner Lindblad Resonances there is a family of stable orbits extending from the center up to the Outer Lindblad Resonance. This family contains the long period orbits near corotation. Other stable families appear between the Inner Lindblad Resonances, outside the Outer Lindblad Resonance, around corotation (short period orbits) and around the center (retrograde). Some families become unstable or disappear in strong bars. A comparison is made with cases having one or no Inner Lindblad Resonance. (12 refs).
A decay heat removal methodology for reuseable orbital transfer vehicles
McDaniel, Patrick J.; Perkins, David R.
1992-07-01
Operation of a nuclear thermal rocket(NTR) as the propulsion system for a reusable orbital transfer vehicle has been considered. This application is the most demanding in terms of designing a multiple restart capability for an NTR. The requirements on a NTR cooling system associated with the nuclear decay heat stored during operation have been evaluated, specifically for a Particle Bed Reactor(PBR) configuration. A three mode method of operation has been identified as required to adequately remove the nuclear decay heat.
Kalman Orbit Optimized Loop Tracking
Young, Lawrence E.; Meehan, Thomas K.
2011-01-01
Under certain conditions of low signal power and/or high noise, there is insufficient signal to noise ratio (SNR) to close tracking loops with individual signals on orbiting Global Navigation Satellite System (GNSS) receivers. In addition, the processing power available from flight computers is not great enough to implement a conventional ultra-tight coupling tracking loop. This work provides a method to track GNSS signals at very low SNR without the penalty of requiring very high processor throughput to calculate the loop parameters. The Kalman Orbit-Optimized Loop (KOOL) tracking approach constitutes a filter with a dynamic model and using the aggregate of information from all tracked GNSS signals to close the tracking loop for each signal. For applications where there is not a good dynamic model, such as very low orbits where atmospheric drag models may not be adequate to achieve the required accuracy, aiding from an IMU (inertial measurement unit) or other sensor will be added. The KOOL approach is based on research JPL has done to allow signal recovery from weak and scintillating signals observed during the use of GPS signals for limb sounding of the Earth s atmosphere. That approach uses the onboard PVT (position, velocity, time) solution to generate predictions for the range, range rate, and acceleration of the low-SNR signal. The low- SNR signal data are captured by a directed open loop. KOOL builds on the previous open loop tracking by including feedback and observable generation from the weak-signal channels so that the MSR receiver will continue to track and provide PVT, range, and Doppler data, even when all channels have low SNR.
Computerized tomography of orbital lesions
International Nuclear Information System (INIS)
Kuroiwa, Mayumi
1981-01-01
Two different types of computerized tomography scanners (CT scanner), i.e. a whole-body CT scanner (GE-CT/T8800) and a cerebral CT scanner (EMI-1010), were compared in the assessment and diagnosis of various orbital lesions. The whole-body CT scanner was found to be advantageous over the cerebral CT scanner for the following reasons: (1) CT images were more informative due to thinner slices associated with smaller-sized and larger-numbered matrices; (2) less artifacts derived from motion of the head or eyeball were produced because of the shorter scanning time; (3) with a devised gantry, coronal dissections were available whenever demanded. (author)
Orbiter fuel cell improvement assessment
International Nuclear Information System (INIS)
Johnson, R.E.
1981-08-01
The history of fuel cells and the theory of fuel cells is given. Expressions for thermodynamic and electrical efficiencies are developed. The voltage losses due to electrode activation, ohmic resistance and ionic diffusion are discussed. Present limitations of the Orbiter Fuel Cell, as well as proposed enhancements, are given. These enhancements are then evaluated and recommendations are given for fuel cell enhancement both for short-range as well as long-range performance improvement. Estimates of reliability and cost savings are given for enhancements where possible
Moran, Susanne I.
2004-01-01
The On-Orbit Software Analysis Research Infusion Project was done by Intrinsyx Technologies Corporation (Intrinsyx) at the National Aeronautics and Space Administration (NASA) Ames Research Center (ARC). The Project was a joint collaborative effort between NASA Codes IC and SL, Kestrel Technology (Kestrel), and Intrinsyx. The primary objectives of the Project were: Discovery and verification of software program properties and dependencies, Detection and isolation of software defects across different versions of software, and Compilation of historical data and technical expertise for future applications
Fermilab | Particle Physics Division
Diversity Education Safety Sustainability and Environment Contact Science Science Particle Physics Neutrinos Scientific Computing Research & Development Key Discoveries Benefits of Particle Physics Particle Superconducting Test Accelerator LHC and Future Accelerators Accelerators for Science and Society Particle Physics
Radiation environment measurements and single event upset observations in sun-synchronous orbit
International Nuclear Information System (INIS)
Dyer, C.S.; Sims, A.J.; Farren, J.; Stephen, J.; Underwood, C.
1991-01-01
This paper reports on analysis of data from the Cosmic Radiation Environment and Dosimetry experiment (CREDO) carried in sun-synchronous polar orbit on UoSat-3 which shows the influence of cosmic rays, trapped protons and solar particles and allows comparison with device behavior
Jupiter's magnetosphere and aurorae observed by the Juno spacecraft during its first polar orbits
DEFF Research Database (Denmark)
Connerney, J. E. P.; Adriani, Alberto; Allegrini, F.
2017-01-01
The Juno spacecraft acquired direct observations of the jovian magnetosphere and auroral emissions from a vantage point above the poles. Juno's capture orbit spanned the jovian magnetosphere from bow shock to the planet, providing magnetic field, charged particle, and wave phenomena context...
Intraosseous hemangioma of the orbit.
Choi, June Seok; Bae, Yong Chan; Kang, Gyu Bin; Choi, Kyung-Un
2018-03-01
Intraosseous hemangioma is an extremely rare tumor that accounts for 1% or fewer of all osseous tumors. The most common sites of its occurrence are the vertebral column and calvaria. Occurrence in a facial bone is very rare. The authors aim to report a case of the surgical treatment of intraosseous hemangioma occurring in the periorbital region, which is a very rare site of occurrence and to introduce our own experiences with the diagnosis and treatment of this condition along with a literature review. A 73-year-old male patient visited our hospital with the chief complaint of a mass touching the left orbital rim. A biopsy was performed by applying a direct incision after local anesthesia. Eventually, intraosseous hemangioma was diagnosed histologically. To fully resect the mass, the orbital floor and zygoma were exposed through a subciliary incision under general anesthesia, and then the tumor was completely eliminated. Bony defect was reconstructed by performing a seventh rib bone graft. Follow-up observation has so far been conducted for 10 months after surgery without recurrence or symptoms.
Chaotic Transport in Circumterrestrial Orbits
Rosengren, Aaron Jay
2018-04-01
The slow deformation of circumterrestrial orbits in the medium region, subject to lunisolar secular resonances, is well approximated by a Hamiltonian system with 2.5 degrees of freedom. This dynamical model is referred to in the astrophysical and celestial dynamics communities as the quadrupolar, secular, hierarchical three-body problem, and, in the non-autonomous case, gives rise to the classical Kozai-Lidov mechanism. In the time-dependent model, brought about in our case by the Moon's perturbed motion, the action variables of the system may experience chaotic variations and large drifts due to the possible overlap of nearby resonances. Using variational chaos indicators, we compute high-resolution portraits of the action space, revealing the existence of tori and structures filling chaotic regions. Our refined and elaborate calculations allow us to isolate precise initial conditions near specific areas of interest and to study their asymptotic behavior in time. We highlight in particular how the drift in phase space is mediated by the complement of the numerically detected KAM tori. Despite their reputed normality, Earth satellite orbits can possess an extraordinarily rich spectrum of dynamical behaviors, and, like the small body remnants of Solar system formation, they have all the complications that make them very interesting candidates for testing the modern tools of chaos theory.
Band crossings in mercury nuclei: effect of occupation of i13/2 neutron orbits
International Nuclear Information System (INIS)
Khadkikar, S.B.; Praharaj, C.R.
1984-04-01
The K=0 + ground band and two rotation-aligned bands (K=1 + or K2 + two quasi-particle band and K=2 + four quasi-particle band) are studied in 198 Hg, 194 Hg and 190 Hg by angular momentum projection from Hartree-Fock and particle-hole intrinsic states. There is a first anomaly in these three nuclei around 8(h/2π) due to the crossing of the ground band and the two quasi-particle band. Because of the nature of occupation of i13/2 orbitals the four quasi-particle band is too highlying in 198 Hg and does not cross the two quasi-particle bands, while such a second crossing occurs in 194 Hg and 190 Hg near 20 (h/2π). (author)
AGS - The ISR computer program for synchrotron design, orbit analysis and insertion matching
International Nuclear Information System (INIS)
Keil, E.; Marti, Y.; Montague, B.W.; Sudboe, A.
1975-01-01
This is a detailed guide to the use of the current version of a FORTRAN program for carrying out computations required in the design or modification of alternating-gradient synchrotrons and storage rings. The program, which runs on the CDC 7600 computer at CERN, computes linear transformation functions, and modifications of parameters to achieve specified properties; it tracks sets of particle trajectories, finds closed orbits when elements of the structure are displaced, computes the equilibrium orbit, designs closed-orbit bumps, tracks betatron functions through the structure, and matches insertions in the structure to specified betatron and dispersion functions. The report supersedes CERN 69-5 (AGS - The ISR computer system for synchrotron design and orbit analysis, by E. Keil and P. Strolin). (Author)
Excitonic Order and Superconductivity in the Two-Orbital Hubbard Model: Variational Cluster Approach
Fujiuchi, Ryo; Sugimoto, Koudai; Ohta, Yukinori
2018-06-01
Using the variational cluster approach based on the self-energy functional theory, we study the possible occurrence of excitonic order and superconductivity in the two-orbital Hubbard model with intra- and inter-orbital Coulomb interactions. It is known that an antiferromagnetic Mott insulator state appears in the regime of strong intra-orbital interaction, a band insulator state appears in the regime of strong inter-orbital interaction, and an excitonic insulator state appears between them. In addition to these states, we find that the s±-wave superconducting state appears in the small-correlation regime, and the dx2 - y2-wave superconducting state appears on the boundary of the antiferromagnetic Mott insulator state. We calculate the single-particle spectral function of the model and compare the band gap formation due to the superconducting and excitonic orders.
Spontaneous orbiting of two spheres levitated in a vibrated liquid.
Pacheco-Martinez, H A; Liao, L; Hill, R J A; Swift, Michael R; Bowley, R M
2013-04-12
In the absence of gravity, particles can form a suspension in a liquid irrespective of the difference in density between the solid and the liquid. If such a suspension is subjected to vibration, there is relative motion between the particles and the fluid which can lead to self-organization and pattern formation. Here, we describe experiments carried out to investigate the behavior of two identical spheres suspended magnetically in a fluid, mimicking weightless conditions. Under vibration, the spheres mutually attract and, for sufficiently large vibration amplitudes, the spheres are observed to spontaneously orbit each other. The collapse of the experimental data onto a single curve indicates that the instability occurs at a critical value of the streaming Reynolds number. Simulations reproduce the observed behavior qualitatively and quantitatively, and are used to identify the features of the flow that are responsible for this instability.
Is the Sky Really Falling? An Overview of Orbital Debris
Hull, Scott M.
2015-01-01
Orbital debris has been a prominent topic for a while, even before the movie Gravity came out. An anti-satellite test and a collision with an operational satellite both produced large highly-publicized debris clouds within recent years. While large objects like abandoned satellites and rocket bodies may be the most recognizable and identifiable concerns, a majority of the daily threat comes from the much more numerous smaller particles. In fact, small particle penetration continues to rank among the leading risks for manned space missions to the International Space Station and beyond. How much 'stuff' is up there, where did it come from, what harm can it do, and what is being done about it? These questions and more will be discussed.
Spin–orbit induced electronic spin separation in semiconductor nanostructures
Kohda, Makoto; Nakamura, Shuji; Nishihara, Yoshitaka; Kobayashi, Kensuke; Ono, Teruo; Ohe, Jun-ichiro; Tokura, Yasuhiro; Mineno, Taiki; Nitta, Junsaku
2012-01-01
The demonstration of quantized spin splitting by Stern and Gerlach is one of the most important experiments in modern physics. Their discovery was the precursor of recent developments in spin-based technologies. Although electrical spin separation of charged particles is fundamental in spintronics, in non-uniform magnetic fields it has been difficult to separate the spin states of charged particles due to the Lorentz force, as well as to the insufficient and uncontrollable field gradients. Here we demonstrate electronic spin separation in a semiconductor nanostructure. To avoid the Lorentz force, which is inevitably induced when an external magnetic field is applied, we utilized the effective non-uniform magnetic field which originates from the Rashba spin–orbit interaction in an InGaAs-based heterostructure. Using a Stern–Gerlach-inspired mechanism, together with a quantum point contact, we obtained field gradients of 108 T m−1 resulting in a highly polarized spin current. PMID:23011136
Spin-orbit induced electronic spin separation in semiconductor nanostructures.
Kohda, Makoto; Nakamura, Shuji; Nishihara, Yoshitaka; Kobayashi, Kensuke; Ono, Teruo; Ohe, Jun-ichiro; Tokura, Yasuhiro; Mineno, Taiki; Nitta, Junsaku
2012-01-01
The demonstration of quantized spin splitting by Stern and Gerlach is one of the most important experiments in modern physics. Their discovery was the precursor of recent developments in spin-based technologies. Although electrical spin separation of charged particles is fundamental in spintronics, in non-uniform magnetic fields it has been difficult to separate the spin states of charged particles due to the Lorentz force, as well as to the insufficient and uncontrollable field gradients. Here we demonstrate electronic spin separation in a semiconductor nanostructure. To avoid the Lorentz force, which is inevitably induced when an external magnetic field is applied, we utilized the effective non-uniform magnetic field which originates from the Rashba spin-orbit interaction in an InGaAs-based heterostructure. Using a Stern-Gerlach-inspired mechanism, together with a quantum point contact, we obtained field gradients of 10(8) T m(-1) resulting in a highly polarized spin current.
Orbit and Optics Distortion in a Nonscaling Muon FFAG
International Nuclear Information System (INIS)
Machida, Shinji
2008-01-01
Finite chromaticity in a nonscaling FFAG makes transverse tunes move during acceleration. Particles have to cross many integer and half-integer resonances although all those tunes are imperfection ones. Plausible argument is that the acceleration is so fast that effects of those resonance crossings are marginal. We did a tracking study in a lattice with alignment and gradient errors to see how the orbit and optics distortion is excited. We found that in a time scale of the muon acceleration, namely total tune changes about one unit per turn, the resonance is not a proper way to describe the beam dynamics. Instead, a random walk model, in which we assume that alignment and gradient errors kick a particle randomly in phase space, well explains the tracking results
Modeling the electron-proton telescope on Solar Orbiter
Energy Technology Data Exchange (ETDEWEB)
Boden, Sebastian; Steinhagen, Jan; Kulkarni, S.R.; Tammen, Jan; Elftmann, Robert; Martin, Cesar; Ravanbakhsh, Ali; Boettcher, Stephan; Seimetz, Lars; Wimmer-Schweingruber, Robert F. [Christian-Albrechts-Universitaet, Kiel (Germany)
2014-07-01
The Electron Proton Telescope (EPT) is one of four sensors in the Energetic Particle Detector suite for Solar Orbiter. It investigates low energy electrons and protons of solar events in an energy range from 20 - 400 keV for electrons and 20 keV - 7 MeV for protons. It distinguishes electrons from protons using a magnet/foil technique with silicon detectors. There will be two EPT units, each with double-barreled telescopes, one looking sunwards/antisunwards and the other north/south. We set up a Monte Carlo model of EPT using the GEANT4 framework, which we can use to simulate interactions of energetic particles in the sensor. Here we present simulation results of the energy coverage for different ion species, and we study how it is possible to distinguish between them.
Vlasov treatment of coherent synchrotron radiation from arbitrary planar orbits
International Nuclear Information System (INIS)
Warnock, R.; Bassi, G.; Ellison, J.A.
2006-01-01
We study the influence of coherent synchrotron radiation (CSR) on particle bunches traveling on arbitrary planar orbits between parallel conducting plates which represent the vacuum chamber. Our goal is to follow the time evolution of the phase space distribution by solving the Vlasov-Maxwell equations in the time domain. This should provide simulations with lower numerical noise than the macro-particle method, and allow one to study such issues as emittance degradation and microbunching due to CSR in bunch compressors. The fields excited by the bunch are computed in the laboratory frame from a new formula that leads to much simpler computations than usual methods. The nonlinear Vlasov equation, formulated in the interaction picture, is integrated in the beam frame by approximating the Perron-Frobenius operator. For application to a chicane bunch compressor we take steps to deal with energy chirp
Universal fluctuations in orbital diamagnetism
Indian Academy of Sciences (India)
P S Pal
published online 31 January 2018. Abstract. Bohr–van ... friction and (c) particle moving in a medium with space-dependent temperature. For all the three cases, the average ..... A M J thanks Department of Science and Technology,. India, for ...
Particle diagnostics for magnetic fusion experiments
International Nuclear Information System (INIS)
Post, D.E.
1983-01-01
This chapter summarizes the subset of diagnostics that relies primarily on the use of particles, and attempts to show how atomic and molecular data play a role in these diagnostics. Discusses passive charge-exchange ion temperature measurements; hydrogen beams for density, ion temperature, q and ZEFF measurements; impurity diagnostics using charge-exchange recombination; plasma electric and magnetic measurements using beams heavier than hydrogen; and alpha particle diagnostics. Points out that as fusion experiments become larger and hotter, most traditional particle diagnostics become difficult because large plasmas are difficult for neutral atoms to penetrate and the gyro-orbits of charged particles need to be larger than typically obtained with present beams to be comparable with the plasma size. Concludes that not only does the current profile affect the plasma stability, but there is a growing opinion that any serious fusion reactor will have to be steady state
On the effects of solar storms to the decaying orbital space debris
International Nuclear Information System (INIS)
Herdiwijaya, Dhani; Rachman, Abdul
2014-01-01
Any man-made object in Earth's orbit that no longer serves a useful purpose is classified as orbital debris. Debris objects come from a variety of sources. The majority is related to satellite fragmentation. Other major sources of debris are propulsion systems, and fragmentation of spent upper stages, payload and mission related debris. Serious concern about orbital debris has been growing. Knowledge of the future debris environment is important to both satellite designers, and mission planners, who need to know what hazards a satellite might encounter during the course of its mission. Therefore, it is important to know how much debris is in orbit, where it is located, and when it will decay. The debris environment is complex and dynamically evolving. Objects of different shape and size behave differently in orbit. The geoeffectiveness space environments include solar flux at 10.7 cm, solar energetic particles flux or speed, solar wind flow pressure, electric field, and geomagnetic indices. We study the decaying orbital debris from Tracking and Impact Prediction (TIP) messages in conjuction with geoeffectiveness space environments through time epoch correlation. We found that the decaying and reentry orbital debris are triggered by space environment enhancement within at least one week before reentry. It is not necessary a transient or high energetic and severe solar storm events are needed in decaying processes. We propose that the gradual enhancement processes of space environment will cause satellite surface charging due to energetic electron and enhance drag force
On the effects of solar storms to the decaying orbital space debris
Energy Technology Data Exchange (ETDEWEB)
Herdiwijaya, Dhani, E-mail: dhani@as.itb.ac.id [Astronomy Division and Bosscha Observatory, Faculty of Mathematics and Natural Sciences, Bandung Institute of Technology, Ganesha 10, Bandung 40132 (Indonesia); Rachman, Abdul [Space Science Center, National Institute of Aeronautics and Space, Junjunan 133, Bandung 40173 (Indonesia)
2014-03-24
Any man-made object in Earth's orbit that no longer serves a useful purpose is classified as orbital debris. Debris objects come from a variety of sources. The majority is related to satellite fragmentation. Other major sources of debris are propulsion systems, and fragmentation of spent upper stages, payload and mission related debris. Serious concern about orbital debris has been growing. Knowledge of the future debris environment is important to both satellite designers, and mission planners, who need to know what hazards a satellite might encounter during the course of its mission. Therefore, it is important to know how much debris is in orbit, where it is located, and when it will decay. The debris environment is complex and dynamically evolving. Objects of different shape and size behave differently in orbit. The geoeffectiveness space environments include solar flux at 10.7 cm, solar energetic particles flux or speed, solar wind flow pressure, electric field, and geomagnetic indices. We study the decaying orbital debris from Tracking and Impact Prediction (TIP) messages in conjuction with geoeffectiveness space environments through time epoch correlation. We found that the decaying and reentry orbital debris are triggered by space environment enhancement within at least one week before reentry. It is not necessary a transient or high energetic and severe solar storm events are needed in decaying processes. We propose that the gradual enhancement processes of space environment will cause satellite surface charging due to energetic electron and enhance drag force.
Mercury's Sodium Exosphere: Observations during the MESSENGER Orbital Phase
Killen, Rosemary M.; Cassidy, Timothy A.; Vervack, Ronald J., Jr.; Burger, Matthew H.; Merkel, Aimee W.; Sarantos, Menelaos; Sprague, Ann L.; McClintock, William E.; Benna, Mehdi; Solomon, Sean C.
2012-01-01
The MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft entered into orbit about Mercury on March 18,2011. We now have approximately five Mercury years of data from orbit. Prior to the MESSENGER mission, Mercury's surface-bounded exosphere was known to contain H, He, Na. K, and Ca. The Ultraviolet and Visible Spectrometer (UVVS) began routine orbital observations of both the dayside and nightside exosphere on March 29. 2011, measuring altitude profiles for all previously detected neutral species except for He and K. We focus here on what we have learned about the sodium exosphere: its spatial, seasonal, and sporadic variation. Observations to date permit delineation of the relative roles of photon-stimulated desorption (PSD) and impact vaporization (IV) from seasonal and spatial effects, as well as of the roles of ions both as sputtering agents and in their possible role to enhance the efficiency of PSD. Correlations of Mercury's neutral sodium exosphere with measurements from MESSENGER's Magnetometer (MAG) and Energetic Particle and Plasma Spectrometer (EPPS) provide insight into the roles of ions and electrons. Models incorporating MAG observations provide a basis for identifying the location and area of the surface exposed to solar wind plasma, and EPPS observations reveal episodic populations of energetic electrons in the magnetosphere and the presence of planetary He(+), 0(+), and Na(+),
Advances in the management of orbital fractures.
Nguyen, P N; Sullivan, P
1992-01-01
Great progress has been made in both the basic science and the clinical knowledge base used in orbital reconstruction. With this, increasing complex orbital reconstructive problems are better managed. The diagnosis, treatment plan, and the actual reconstruction have evolved to a higher level. Several areas of progress are of note: the greater appreciation of the intimate relation between the bony orbit's shape and the position of the globe; application of computer technology in orbital injuries; effect of rigid fixation on autogenous and alloplastic graft; and the use of advanced biocompatible synthetic materials in orbital reconstruction. Although this progress has great impact on treatment of orbital injuries, there are many unanswered challenges in the treatment of the fragile frame of the window to the human soul.
Orbit determination for ISRO satellite missions
Rao, Ch. Sreehari; Sinha, S. K.
Indian Space Research Organisation (ISRO) has been successful in using the in-house developed orbit determination and prediction software for satellite missions of Bhaskara, Rohini and APPLE. Considering the requirements of satellite missions, software packages are developed, tested and their accuracies are assessed. Orbit determination packages developed are SOIP, for low earth orbits of Bhaskara and Rohini missions, ORIGIN and ODPM, for orbits related to all phases of geo-stationary missions and SEGNIP, for drift and geo-stationary orbits. Software is tested and qualified using tracking data of SIGNE-3, D5-B, OTS, SYMPHONIE satellites with the help of software available with CNES, ESA and DFVLR. The results match well with those available from these agencies. These packages have supported orbit determination successfully throughout the mission life for all ISRO satellite missions. Member-Secretary
Orbits of the inner satellites of Neptune
Brozovic, Marina; Showalter, Mark R.; Jacobson, Robert Arthur; French, Robert S.; de Pater, Imke; Lissauer, Jack
2018-04-01
We report on the numerically integrated orbits of seven inner satellites of Neptune, including S/2004 N1, the last moon of Neptune to be discovered by the Hubble Space Telescope (HST). The dataset includes Voyager imaging data as well as the HST and Earth-based astrometric data. The observations span time period from 1989 to 2016. Our orbital model accounts for the equatorial bulge of Neptune, perturbations from the Sun and the planets, and perturbations from Triton. The initial orbital integration assumed that the satellites are massless, but the residuals improved significantly as the masses adjusted toward values that implied that the density of the satellites is in the realm of 1 g/cm3. We will discuss how the integrated orbits compare to the precessing ellipses fits, mean orbital elements, current orbital uncertainties, and the need for future observations.
Computed tomography of the eye and orbit
International Nuclear Information System (INIS)
Hammerschlag, S.B.; Hesselink, J.R.; Weber, A.L.
1982-01-01
This book is the product of the evolution of computed tomography (CT) into subspecialization and the need for one source of information for the busy radiologist. The authors have succeeded in providing a readable overview of orbital CT as well as a reference book. The book is divided into seven major catagories of pathology (Neurofibromatosis, Primary Orbital Neoplasms, Secondary and Metastic Tumors of the Orbit, Vascular Disorders, Inflammatory Disease, Occular Lesions, and Trauma) after separate discussions of anatomy and technique
Neural networks and orbit control in accelerators
International Nuclear Information System (INIS)
Bozoki, E.; Friedman, A.
1994-01-01
An overview of the architecture, workings and training of Neural Networks is given. We stress the aspects which are important for the use of Neural Networks for orbit control in accelerators and storage rings, especially its ability to cope with the nonlinear behavior of the orbit response to 'kicks' and the slow drift in the orbit response during long-term operation. Results obtained for the two NSLS storage rings with several network architectures and various training methods for each architecture are given
Operational factors affecting microgravity levels in orbit
Olsen, R. E.; Mockovciak, J., Jr.
1980-01-01
Microgravity levels desired for proposed materials processing payloads are fundamental considerations in the design of future space platforms. Disturbance sources, such as aerodynamic drag, attitude control torques, crew motion and orbital dynamics, influence the microgravity levels attainable in orbit. The nature of these effects are assessed relative to platform design parameters such as orbital altitude and configuration geometry, and examples are presented for a representative spacecraft configuration. The possible applications of control techniques to provide extremely low acceleration levels are also discussed.
Orbital structure in oscillating galactic potentials
Terzić, Balša; Kandrup, Henry E.
2004-01-01
Subjecting a galactic potential to (possibly damped) nearly periodic, time-dependent variations can lead to large numbers of chaotic orbits experiencing systematic changes in energy, and the resulting chaotic phase mixing could play an important role in explaining such phenomena as violent relaxation. This paper focuses on the simplest case of spherically symmetric potentials subjected to strictly periodic driving with the aim of understanding precisely why orbits become chaotic and under what circumstances they will exhibit systematic changes in energy. Four unperturbed potentials V0(r) were considered, each subjected to a time dependence of the form V(r, t) =V0(r)(1 +m0 sinωt). In each case, the orbits divide clearly into regular and chaotic, distinctions which appear absolute. In particular, transitions from regularity to chaos are seemingly impossible. Over finite time intervals, chaotic orbits subdivide into what can be termed `sticky' chaotic orbits, which exhibit no large-scale secular changes in energy and remain trapped in the phase-space region where they started; and `wildly' chaotic orbits, which do exhibit systematic drifts in energy as the orbits diffuse to different phase-space regions. This latter distinction is not absolute, transitions corresponding apparently to orbits penetrating a `leaky' phase-space barrier. The three different orbit types can be identified simply in terms of the frequencies for which their Fourier spectra have the most power. An examination of the statistical properties of orbit ensembles as a function of driving frequency ω allows us to identify the specific resonances that determine orbital structure. Attention focuses also on how, for fixed amplitude m0, such quantities as the mean energy shift, the relative measure of chaotic orbits and the mean value of the largest Lyapunov exponent vary with driving frequency ω and how, for fixed ω, the same quantities depend on m0.
Alpha particle loss in the TFTR DT experiments
International Nuclear Information System (INIS)
Zweben, S.J.; Darrow, D.S.; Herrmann, H.W.
1995-01-01
Alpha particle loss was measured during the TFTR DT experiments using a scintillator detector located at the vessel bottom in the ion grad-B drift direction. The DT alpha particle loss to this detector was consistent with the calculated first-orbit loss over the whole range of plasma current I=0.6-2.7 MA. In particular, the alpha particle loss rate per DT neutron did not increase significantly with fusion power up to 10.7 MW, indicating the absence of any new ''collective'' alpha particle loss processes in these experiments
Prediction Model for Relativistic Electrons at Geostationary Orbit
Khazanov, George V.; Lyatsky, Wladislaw
2008-01-01
We developed a new prediction model for forecasting relativistic (greater than 2MeV) electrons, which provides a VERY HIGH correlation between predicted and actually measured electron fluxes at geostationary orbit. This model implies the multi-step particle acceleration and is based on numerical integrating two linked continuity equations for primarily accelerated particles and relativistic electrons. The model includes a source and losses, and used solar wind data as only input parameters. We used the coupling function which is a best-fit combination of solar wind/interplanetary magnetic field parameters, responsible for the generation of geomagnetic activity, as a source. The loss function was derived from experimental data. We tested the model for four year period 2004-2007. The correlation coefficient between predicted and actual values of the electron fluxes for whole four year period as well as for each of these years is stable and incredibly high (about 0.9). The high and stable correlation between the computed and actual electron fluxes shows that the reliable forecasting these electrons at geostationary orbit is possible.
Orbit stability of the ALS storage ring
International Nuclear Information System (INIS)
Keller, R.; Nishimura, H.; Biocca, A.
1997-05-01
The Advanced Light Source (ALS) storage ring, a synchrotron light source of the third generation, is specified to maintain its electron orbit stable within one tenth of the rms beam size. In the absence of a dedicated orbit feed-back system, several orbit-distorting effects were investigated, aided by a new interactive simulation tool, the code TRACY V. The effort has led to a better understanding of the behavior of a variety of accelerator subsystems and in consequence produced a substantial improvement in day-to-day orbit stability
Hydrodynamic capture of microswimmers into sphere-bound orbits.
Takagi, Daisuke; Palacci, Jérémie; Braunschweig, Adam B; Shelley, Michael J; Zhang, Jun
2014-03-21
Self-propelled particles can exhibit surprising non-equilibrium behaviors, and how they interact with obstacles or boundaries remains an important open problem. Here we show that chemically propelled micro-rods can be captured, with little change in their speed, into close orbits around solid spheres resting on or near a horizontal plane. We show that this interaction between sphere and particle is short-range, occurring even for spheres smaller than the particle length, and for a variety of sphere materials. We consider a simple model, based on lubrication theory, of a force- and torque-free swimmer driven by a surface slip (the phoretic propulsion mechanism) and moving near a solid surface. The model demonstrates capture, or movement towards the surface, and yields speeds independent of distance. This study reveals the crucial aspects of activity–driven interactions of self-propelled particles with passive objects, and brings into question the use of colloidal tracers as probes of active matter.
Test results and in-orbit operation of the Infrared Astronomical Satellite circumvention circuit
Long, E. C.; Langford, D.
1984-01-01
The IRAS circumvention circuit (CC) eliminates the unwanted charged-particle pulses from the IR signal. The operation of the CC along with preflight and in-orbit testing is described. Ground testing of the brassboard circuit using a simulated preamplifier output showed that the CC would perform the circumvention function as designed. When all flight detectors and preamplifiers became available, the CC was tested using a gamma source to simulate charged-particle sources; with the low energy deposited in the detectors (20 keV average) the noise was reduced by up to 5 times with the CC turned on. In-orbit results show that the CC decreases the unwanted charged-particle background noise by up to two orders of magnitude. The difference in the results with the CC on and off is so great that the science team has recommended that no data be taken with the CC off.
Basic Evidence and Properties of Single-Particle States in Nuclei
Energy Technology Data Exchange (ETDEWEB)
Cindro, N. [Institute ' ' Rudjer Boskovic' ' , Zagreb, Yugoslavia (Croatia)
1970-07-15
1. Introduction: the shell-model orbitals; 2. Information about single-particle orbitals: a critical evaluation; 3. Experimental evidence: 3.1. The lead region; 3.2. The calcium region; 3.3. Nuclei far from closed shells; 4. Conclusion. (author)
A test particle motion in the Kerr field with fluctuating perturbations
International Nuclear Information System (INIS)
Zhuk, I.T.; Piragas, K.A.
1982-01-01
Motion of a stochastic test particle in the Kerr black hole field in the approximation of Brown interaction is considered. Probability distribution of orbit position by the latitude angle is revealed, bifurcation values of their parameters are determined. Fluctuating instability of orbits characteristic of critical modes of motion is investigated, properties of some statistical characteristics of the system are identified
Alpha particle physics experiments in the Tokamak Fusion Test Reactor
International Nuclear Information System (INIS)
Zweben, S.J.; Budny, R.V.; Darrow, D.S.; Medley, S.S.; Nazikian, R.; Stratton, B.C.; Synakowski, E.J.; Taylor, G.
2000-01-01
Alpha particle physics experiments were done on TFTR during its DT run from 1993 to 1997. These experiments utilized several new alpha particle diagnostics and hundreds of DT discharges to characterize the alpha particle confinement and wave-particle interactions. In general, the results from the alpha particle diagnostics agreed with the classical single particle confinement model in MHD quiescent discharges. The alpha loss due to toroidal field ripple was identified in some cases, and the low radial diffusivity inferred for high energy alphas was consistent with orbit averaging over small scale turbulence. Finally, the observed alpha particle interactions with sawteeth, toroidal Alfven eigenmodes and ICRF waves were approximately consistent with theoretical modelling. What was learned is reviewed and what remains to be understood is identified. (author)
Schwaab, Douglas G.
1991-01-01
A mathematical programing model is presented to optimize the selection of Orbital Replacement Unit on-orbit spares for the Space Station. The model maximizes system availability under the constraints of logistics resupply-cargo weight and volume allocations.
Orbital Resonances in the Vinti Solution
Zurita, L. D.
As space becomes more congested, contested, and competitive, high-accuracy orbital predictions become critical for space operations. Current orbit propagators use the two-body solution with perturbations added, which have significant error growth when numerically integrated for long time periods. The Vinti Solution is a more accurate model than the two-body problem because it also accounts for the equatorial bulge of the Earth. Unfortunately, the Vinti solution contains small divisors near orbital resonances in the perturbative terms of the Hamiltonian, which lead to inaccurate orbital predictions. One approach to avoid the small divisors is to apply transformation theory, which is presented in this research. The methodology of this research is to identify the perturbative terms of the Vinti Solution, perform a coordinate transformation, and derive the new equations of motion for the Vinti system near orbital resonances. An analysis of these equations of motion offers insight into the dynamics found near orbital resonances. The analysis in this research focuses on the 2:1 resonance, which includes the Global Positioning System. The phase portrait of a nominal Global Positioning System satellite orbit is found to contain a libration region and a chaotic region. Further analysis shows that the dynamics of the 2:1 resonance affects orbits with semi-major axes ranging from -5.0 to +5.4 kilometers from an exactly 2:1 resonant orbit. Truth orbits of seven Global Positioning System satellites are produced for 10 years. Two of the satellites are found to be outside of the resonance region and three are found to be influenced by the libration dynamics of the resonance. The final satellite is found to be influenced by the chaotic dynamics of the resonance. This research provides a method of avoiding the small divisors found in the perturbative terms of the Vinti Solution near orbital resonances.
Small Orbital Stereo Tracking Camera Technology Development
Gagliano, L.; Bryan, T.; MacLeod, T.
On-Orbit Small Debris Tracking and Characterization is a technical gap in the current National Space Situational Awareness necessary to safeguard orbital assets and crew. This poses a major risk of MOD damage to ISS and Exploration vehicles. In 2015 this technology was added to NASAs Office of Chief Technologist roadmap. For missions flying in or assembled in or staging from LEO, the physical threat to vehicle and crew is needed in order to properly design the proper level of MOD impact shielding and proper mission design restrictions. Need to verify debris flux and size population versus ground RADAR tracking. Use of ISS for In-Situ Orbital Debris Tracking development provides attitude, power, data and orbital access without a dedicated spacecraft or restricted operations on-board a host vehicle as a secondary payload. Sensor Applicable to in-situ measuring orbital debris in flux and population in other orbits or on other vehicles. Could enhance safety on and around ISS. Some technologies extensible to monitoring of extraterrestrial debris as well To help accomplish this, new technologies must be developed quickly. The Small Orbital Stereo Tracking Camera is one such up and coming technology. It consists of flying a pair of intensified megapixel telephoto cameras to evaluate Orbital Debris (OD) monitoring in proximity of International Space Station. It will demonstrate on-orbit optical tracking (in situ) of various sized objects versus ground RADAR tracking and small OD models. The cameras are based on Flight Proven Advanced Video Guidance Sensor pixel to spot algorithms (Orbital Express) and military targeting cameras. And by using twin cameras we can provide Stereo images for ranging & mission redundancy. When pointed into the orbital velocity vector (RAM), objects approaching or near the stereo camera set can be differentiated from the stars moving upward in background.
Orbital Dynamics of Low-Earth Orbit Laser-Propelled Space Vehicles
International Nuclear Information System (INIS)
Yamakawa, Hiroshi; Funaki, Ikkoh; Komurasaki, Kimiya
2008-01-01
Trajectories applicable to laser-propelled space vehicles with a laser station in low-Earth orbit are investigated. Laser vehicles are initially located in the vicinity of the Earth-orbiting laser station in low-earth orbit at an altitude of several hundreds kilometers, and are accelerated by laser beaming from the laser station. The laser-propelled vehicles start from low-earth orbit and finally escape from the Earth gravity well, enabling interplanetary trajectories and planetary exploration
Sośnica, Krzysztof; Prange, Lars; Kaźmierski, Kamil; Bury, Grzegorz; Drożdżewski, Mateusz; Zajdel, Radosław; Hadas, Tomasz
2018-02-01
The space segment of the European Global Navigation Satellite System (GNSS) Galileo consists of In-Orbit Validation (IOV) and Full Operational Capability (FOC) spacecraft. The first pair of FOC satellites was launched into an incorrect, highly eccentric orbital plane with a lower than nominal inclination angle. All Galileo satellites are equipped with satellite laser ranging (SLR) retroreflectors which allow, for example, for the assessment of the orbit quality or for the SLR-GNSS co-location in space. The number of SLR observations to Galileo satellites has been continuously increasing thanks to a series of intensive campaigns devoted to SLR tracking of GNSS satellites initiated by the International Laser Ranging Service. This paper assesses systematic effects and quality of Galileo orbits using SLR data with a main focus on Galileo satellites launched into incorrect orbits. We compare the SLR observations with respect to microwave-based Galileo orbits generated by the Center for Orbit Determination in Europe (CODE) in the framework of the International GNSS Service Multi-GNSS Experiment for the period 2014.0-2016.5. We analyze the SLR signature effect, which is characterized by the dependency of SLR residuals with respect to various incidence angles of laser beams for stations equipped with single-photon and multi-photon detectors. Surprisingly, the CODE orbit quality of satellites in the incorrect orbital planes is not worse than that of nominal FOC and IOV orbits. The RMS of SLR residuals is even lower by 5.0 and 1.5 mm for satellites in the incorrect orbital planes than for FOC and IOV satellites, respectively. The mean SLR offsets equal -44.9, -35.0, and -22.4 mm for IOV, FOC, and satellites in the incorrect orbital plane. Finally, we found that the empirical orbit models, which were originally designed for precise orbit determination of GNSS satellites in circular orbits, provide fully appropriate results also for highly eccentric orbits with variable linear
ORBIT: A CODE FOR COLLECTIVE BEAM DYNAMICS IN HIGH INTENSITY RINGS
International Nuclear Information System (INIS)
HOLMES, J.A.; DANILOV, V.; GALAMBOS, J.; SHISHLO, A.; COUSINEAU, S.; CHOU, W.; MICHELOTTI, L.; OSTIGUY, J.F.; WEI, J.
2002-01-01
We are developing a computer code, ORBIT, specifically for beam dynamics calculations in high-intensity rings. Our approach allows detailed simulation of realistic accelerator problems. ORBIT is a particle-in-cell tracking code that transports bunches of interacting particles through a series of nodes representing elements, effects, or diagnostics that occur in the accelerator lattice. At present, ORBIT contains detailed models for strip-foil injection, including painting and foil scattering; rf focusing and acceleration; transport through various magnetic elements; longitudinal and transverse impedances; longitudinal, transverse, and three-dimensional space charge forces; collimation and limiting apertures; and the calculation of many useful diagnostic quantities. ORBIT is an object-oriented code, written in C++ and utilizing a scripting interface for the convenience of the user. Ongoing improvements include the addition of a library of accelerator maps, BEAMLINE/MXYZPTLK, the introduction of a treatment of magnet errors and fringe fields; the conversion of the scripting interface to the standard scripting language, Python; and the parallelization of the computations using MPI. The ORBIT code is an open source, powerful, and convenient tool for studying beam dynamics in high-intensity rings
ORBIT: A Code for Collective Beam Dynamics in High-Intensity Rings
Holmes, J. A.; Danilov, V.; Galambos, J.; Shishlo, A.; Cousineau, S.; Chou, W.; Michelotti, L.; Ostiguy, J.-F.; Wei, J.
2002-12-01
We are developing a computer code, ORBIT, specifically for beam dynamics calculations in high-intensity rings. Our approach allows detailed simulation of realistic accelerator problems. ORBIT is a particle-in-cell tracking code that transports bunches of interacting particles through a series of nodes representing elements, effects, or diagnostics that occur in the accelerator lattice. At present, ORBIT contains detailed models for strip-foil injection, including painting and foil scattering; rf focusing and acceleration; transport through various magnetic elements; longitudinal and transverse impedances; longitudinal, transverse, and three-dimensional space charge forces; collimation and limiting apertures; and the calculation of many useful diagnostic quantities. ORBIT is an object-oriented code, written in C++ and utilizing a scripting interface for the convenience of the user. Ongoing improvements include the addition of a library of accelerator maps, BEAMLINE/MXYZPTLK; the introduction of a treatment of magnet errors and fringe fields; the conversion of the scripting interface to the standard scripting language, Python; and the parallelization of the computations using MPI. The ORBIT code is an open source, powerful, and convenient tool for studying beam dynamics in high-intensity rings.
ORBIT: A code for collective beam dynamics in high-intensity rings
International Nuclear Information System (INIS)
Holmes, J.A.; Danilov, V.; Galambos, J.; Shishlo, A.; Cousineau, S.; Chou, W.; Michelotti, L.; Ostiguy, J.-F.; Wei, J.
2002-01-01
We are developing a computer code, ORBIT, specifically for beam dynamics calculations in high-intensity rings. Our approach allows detailed simulation of realistic accelerator problems. ORBIT is a particle-in-cell tracking code that transports bunches of interacting particles through a series of nodes representing elements, effects, or diagnostics that occur in the accelerator lattice. At present, ORBIT contains detailed models for strip-foil injection, including painting and foil scattering; rf focusing and acceleration; transport through various magnetic elements; longitudinal and transverse impedances; longitudinal, transverse, and three-dimensional space charge forces; collimation and limiting apertures; and the calculation of many useful diagnostic quantities. ORBIT is an object-oriented code, written in C++ and utilizing a scripting interface for the convenience of the user. Ongoing improvements include the addition of a library of accelerator maps, BEAMLINE/MXYZPTLK; the introduction of a treatment of magnet errors and fringe fields; the conversion of the scripting interface to the standard scripting language, Python; and the parallelization of the computations using MPI. The ORBIT code is an open source, powerful, and convenient tool for studying beam dynamics in high-intensity rings
Fermilab | Science | Particle Physics
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Acoustically Induced Microparticle Orbiting and Clustering on a Solid Surface
Abdel-Fattah, A.; Tarimala, S.; Roberts, P. M.
2008-12-01
Behavior of colloidal particles in the bulk solution or at interfaces under the effect of high-frequency acoustics is critical to many seemingly different applications ranging from enhanced oil recovery to improved mixing in microfluidic channels and from accelerated contaminant extractions to surface cleaning, drug delivery and microelectronics. It can be detrimental or beneficial, depending on the application. In medical research, flow cytometry and microfluidics, for example, acoustically induced clustering of tracer particles and/or their sticking to the walls of channels, vessels, or tubes often becomes a problem. On the other hand, it can be tailored to enhance processes such as mixing in microfluidic devices, particle separation and sizing, and power generation microdevices. To better understand the underlying mechanisms, microscopic visualization experiments were performed in which polystyrene fluorescent (468/508 nm wavelength) microspheres with a mean diameter of 2.26-µm and density of 1.05 g/cm3, were suspended in either de-ionized water or a 0.1M NaCl solution. The freshly-prepared colloidal suspension was injected into a parallel-plate glass flow cell, which was subjected to high-frequency acoustics (200-500 kHz) through a piezoelectric transducer attached to one of the cell's outer walls. When the suspending medium is de-ionized water, acoustic stimulation of the cell at 313 kHz induced three distinct particle behaviors: 1) entrainment and bulk transport via wavelength-scale Rayleigh streaming, 2) transport via direct radiation forces to concentrate at nodal or anti-nodal planes, and 3) entrapment via boundary layer vorticular microstreaming resulting in mobile particles orbiting deposited particles. This latter phenomenon is intriguing. It occurs at specific frequencies and the shape of the orbits is determined by the applied frequency, whereas the rotation speed is proportional to the applied amplitude. At the higher ionic strength, on the other
Simulated orbits of heavy planetary ions at Mars for different IMF configurations
Curry, Shannon; Luhmann, Janet; Livi, Roberto; Hara, Takuya; Dong, Chuanfei; Ma, Yingjuan; McFadden, James; Bougher, Stephen
2014-11-01
We present simulated detections of O+, O2+ and CO2+ ions at Mars along a virtual orbit in the Mars space environment. Planetary pick-up ions are formed through the direct interaction of the solar wind with the neutral upper atmosphere, causing the newly created ions to be picked up and accelerated by the background convective electric field. Because previous missions such as Mars Global Surveyor (MGS) and Mars Express (MEX) have not been able to measure the interplanetary magnetic field (IMF) components simultaneously with plasma measurements, the response of heavy planetary pick-up ions to changes in the IMF has not been well characterized. Using a steady-state multi-species MHD model to provide the background electric and magnetic fields, the Mars Test Particle (MTP) simulation can trace each of these particles along field lines in near-Mars space and construct virtual ion detections from a spacecraft orbit. Specifically, we will present energy-time spectrograms and velocity space distributions (VSDs) for a selection of orbits during different IMF configurations and solar cycle conditions. These simulated orbits have broader implications for how to measure ion escape. Using individual particle traces, the origin and trajectories of different ion populations can be analyzed in order to assess how and where they contribute to the total atmospheric escape rate, which is a major objective of the upcoming MAVEN mission.
"Diffusion" region of magnetic reconnection: electron orbits and the phase space mixing
Kropotkin, Alexey P.
2018-05-01
The nonlinear dynamics of electrons in the vicinity of magnetic field neutral lines during magnetic reconnection, deep inside the diffusion region where the electron motion is nonadiabatic, has been numerically analyzed. Test particle orbits are examined in that vicinity, for a prescribed planar two-dimensional magnetic field configuration and with a prescribed uniform electric field in the neutral line direction. On electron orbits, a strong particle acceleration occurs due to the reconnection electric field. Local instability of orbits in the neighborhood of the neutral line is pointed out. It combines with finiteness of orbits due to particle trapping by the magnetic field, and this should lead to the effect of mixing in the phase space, and the appearance of dynamical chaos. The latter may presumably be viewed as a mechanism producing finite conductivity in collisionless plasma near the neutral line. That conductivity is necessary to provide violation of the magnetic field frozen-in condition, i.e., for magnetic reconnection to occur in that region.
On protection of freedom's solar dynamic radiator from the orbital debris environment. Part 1
International Nuclear Information System (INIS)
Rhatigan, J.L.
1992-01-01
A great deal of experimentation and analysis has been performed to quantify penetration thresholds of components which will experience orbital debris impacts. Penetration has been found to depend upon mission-specific parameters such as orbital altitude, inclination, and orientation of the component; and upon component specific parameters such as material, density, and the geometry particular to its shielding. Experimental results are highly dependent upon shield configuration and cannot be extrapolated with confidence to alternate shield configurations. Also, current experimental capabilities are limited to velocities which only approach the lower limit of predicted orbital debris velocities. Therefore, prediction of the penetrating particle size for a particular component having a complex geometry remains highly uncertain. This paper describes the approach developed to assess on-orbit survivability, and include the type of particle and particle population expected to defeat the radiator bumpering (i.e., penetrate a fluid flow tube). Results of preliminary hypervelocity impact testing performed on radiator panel samples (in the 6 to 7 km/sec velocity range) are also presented. Plans for further analyses and testing are discussed. These efforts are expected to lead to a radiator design which will perform to Space Station Freedom requirements over the expected lifetime
Physical and chemical characteristics of interplanetary dust particles
International Nuclear Information System (INIS)
Gruen, E.
1981-01-01
For the first time, the micrometeoroid experiment on board of Helios allowed the measurement of physical and chemical characteristics of interplanetary dust particles between 0.3AU and 1AU solar distance. During the first 10 orbits of Helios 1,235 impacts of micrometeoroids have been detected. 83 particles have been registered by the ecliptic sensor and 152 by the south sensor. Most of the particles detected by the ecliptic sensor had masses 10 -13 g -10 g and impacted the sensor from the apex direction. The particles observed by the south sensor had masses 10 -15 g -9 g and impacted the sensor from all directions with a slightly enhanced flux from solar direction. The average impact speed of particles with masses 10 -13 g -10 g was 15km/s. From 1AU to.3AU, the observed paritcle flux increased by a factor 5-10. The orbits of the registered particles are highly eccentric, e approx. >= 0.6, and some are hyperbolic. The mass spectra measured upon impact allow the classification of chondritic and iron-rich particles. Approx. 20% of the particles had low densities rho 3 . On 4 particles, a positive electric charge has been observed. (orig.) [de
Orbiting compressor for residential air-conditioners
Energy Technology Data Exchange (ETDEWEB)
Kim, Hyun Jin; Kim, Woo Young; Ahn, Jong Min [Department of Mechanical Engineering, University of Incheon, 12-1 Songdo-dong, Yeonsu-gu, Incheon 406-840 (Korea)
2010-01-15
A new type of compressor, called an orbiting compressor, is introduced in this paper. The orbiting compressor is characterized by an orbiting piston, and the piston or orbiter consists of a circular base plate and a ring type vane protruding vertically from the base plate. The orbiter is made to orbit in an annular space formed between two concentric circular walls via an Oldham-ring mechanism, producing two sealed gas pockets on both sides of the vane wrap with a 180 phase difference. This operating mechanism leads to alternating compression and discharge processes, which results in low torque variation. The orbiting compressor has been designed for an R410A residential air conditioner with a cooling capacity of 10.0 kW. The performance of the orbiting compressor model has been analytically investigated, where the volumetric, adiabatic and mechanical efficiencies were calculated to be 94.8%, 90.4% and 93.4%, respectively for the ARI condition. The EER was estimated to be about 10.86 with a motor efficiency of 89%. (author)
Posttraumatic Orbital Emphysema: A Numerical Model
Directory of Open Access Journals (Sweden)
Andrzej Skorek
2014-01-01
Full Text Available Orbital emphysema is a common symptom accompanying orbital fracture. The pathomechanism is still not recognized and the usually assumed cause, elevated pressure in the upper airways connected with sneezing or coughing, does not always contribute to the occurrence of this type of fracture. Observations based on the finite model (simulating blowout type fracture of the deformations of the inferior orbital wall after a strike in its lower rim. Authors created a computer numeric model of the orbit with specified features—thickness and resilience modulus. During simulation an evenly spread 14400 N force was applied to the nodular points in the inferior rim (the maximal value not causing cracking of the outer rim, but only ruptures in the inferior wall. The observation was made from 1·10-3 to 1·10-2 second after a strike. Right after a strike dislocations of the inferior orbital wall toward the maxillary sinus were observed. Afterwards a retrograde wave of the dislocation of the inferior wall toward the orbit was noticed. Overall dislocation amplitude reached about 6 mm. Based on a numeric model of the orbit submitted to a strike in the inferior wall an existence of a retrograde shock wave causing orbital emphysema has been found.
Strange diquarks and orbital excitations of hyperons
International Nuclear Information System (INIS)
Kondratyuk, L.A.; Ralchenko, Yu.V.; Vasilets, A.V.
1987-01-01
Using the model of the QCD string with spin-orbital interaction the masses of strange diquarks are determined. The spectra of orbital excitations of the Λ and Σ hyperons are calculated and discussed. Also the decay modes for Λ's and Σ's are considered
Characteristics of pellet injuries to the orbit.
Kükner, A Sahap; Yilmaz, Turgut; Celebi, Serdal; Karslioğlu, Safak; Alagöz, Gürsoy; Serin, Didem; Acar, M Akif; Ozveren, M Faik
2009-01-01
To investigate the features of orbital injuries by pellets fired from the front. Retrospective, 4 cases of pellet injuries. Five orbits of 4 patients who sustained pellet injuries received from the front were reviewed retrospectively. The course of injury and results were assessed. Radiological examinations were reviewed. The patients were evaluated between December 1996 and June 2004. Five orbits of 4 patients sustained injuries caused by pellets fired from an anterior direction. The globe in the injured orbit was intact in 2 cases. Severe loss of vision was also present in these 2 globes due to optic nerve involvement. Final visual acuity was down to no light perception in 4 eyes and limited to light perception in 1 eye. The prognosis of orbital pellet injuries is, unfortunately, poor. A pellet passing through the floor of the orbit often causes double perforation of the globe and, once in the orbital aperture, it travels towards the apex as a result of the conical shape of the orbit and lodges in the optic canal or its entrance, severely damaging the optic nerve. Surgery or other treatments are usually unsuccessful. Even if the globe is intact, vision is usually severely impaired. Copyright 2009 S. Karger AG, Basel.
ORBITAL CELLULITIS COMPLICATING SINUSITIS: A 15-YEAR ...
African Journals Online (AJOL)
Dr. NWaorgu
cavernous sinus thrombosis, and brain abscess. 3, 4 In ... left orbit was involved in 55% and the right in 31% while it was bilateral ... Figure 1: Age and sex of patients with orbital cellulitis. 0. 5 ... However, Kenny et al and Child have suggested ...
Hurlbert, Eric A.
2001-01-01
This slide presentation reviews the Space Shuttle's On-Orbit Propulsion systems: the Orbital Maneuvering System (OMS) and the Reaction Control System (RCS). The functions of each of the systems is described, and the diagrams of the systems are presented. The OMS/RCS thruster is detailed and a trade study comparison of non-toxic propellants is presented.
Summary of the Orbiter mechanical systems
Kiker, J.; Hinson, K.
1979-01-01
Major mechanical systems of the Orbiter space vehicle are summarized with respect to general design details, manner of operation, expected performance, and, where applicable, unique features. A synopsis of data obtained during the five atmospheric flight tests of spacecraft OV-101 and status of the systems for the first orbital spacecraft STS-1 are presented.
Linear Magnetoelectric Effect by Orbital Magnetism
Scaramucci, A.; Bousquet, E.; Fechner, M.; Mostovoy, M.; Spaldin, N. A.
2012-01-01
We use symmetry analysis and first-principles calculations to show that the linear magnetoelectric effect can originate from the response of orbital magnetic moments to the polar distortions induced by an applied electric field. Using LiFePO4 as a model compound we show that spin-orbit coupling
Efficient orbit integration by manifold correction methods.
Fukushima, Toshio
2005-12-01
Triggered by a desire to investigate, numerically, the planetary precession through a long-term numerical integration of the solar system, we developed a new formulation of numerical integration of orbital motion named manifold correct on methods. The main trick is to rigorously retain the consistency of physical relations, such as the orbital energy, the orbital angular momentum, or the Laplace integral, of a binary subsystem. This maintenance is done by applying a correction to the integrated variables at each integration step. Typical methods of correction are certain geometric transformations, such as spatial scaling and spatial rotation, which are commonly used in the comparison of reference frames, or mathematically reasonable operations, such as modularization of angle variables into the standard domain [-pi, pi). The form of the manifold correction methods finally evolved are the orbital longitude methods, which enable us to conduct an extremely precise integration of orbital motions. In unperturbed orbits, the integration errors are suppressed at the machine epsilon level for an indefinitely long period. In perturbed cases, on the other hand, the errors initially grow in proportion to the square root of time and then increase more rapidly, the onset of which depends on the type and magnitude of the perturbations. This feature is also realized for highly eccentric orbits by applying the same idea as used in KS-regularization. In particular, the introduction of time elements greatly enhances the performance of numerical integration of KS-regularized orbits, whether the scaling is applied or not.
Continuation of Sets of Constrained Orbit Segments
DEFF Research Database (Denmark)
Schilder, Frank; Brøns, Morten; Chamoun, George Chaouki
Sets of constrained orbit segments of time continuous flows are collections of trajectories that represent a whole or parts of an invariant set. A non-trivial but simple example is a homoclinic orbit. A typical representation of this set consists of an equilibrium point of the flow and a trajectory...... that starts close and returns close to this fixed point within finite time. More complicated examples are hybrid periodic orbits of piecewise smooth systems or quasi-periodic invariant tori. Even though it is possible to define generalised two-point boundary value problems for computing sets of constrained...... orbit segments, this is very disadvantageous in practice. In this talk we will present an algorithm that allows the efficient continuation of sets of constrained orbit segments together with the solution of the full variational problem....
Methods of orbit correction system optimization
International Nuclear Information System (INIS)
Chao, Yu-Chiu.
1997-01-01
Extracting optimal performance out of an orbit correction system is an important component of accelerator design and evaluation. The question of effectiveness vs. economy, however, is not always easily tractable. This is especially true in cases where betatron function magnitude and phase advance do not have smooth or periodic dependencies on the physical distance. In this report a program is presented using linear algebraic techniques to address this problem. A systematic recipe is given, supported with quantitative criteria, for arriving at an orbit correction system design with the optimal balance between performance and economy. The orbit referred to in this context can be generalized to include angle, path length, orbit effects on the optical transfer matrix, and simultaneous effects on multiple pass orbits
CASA Uno GPS orbit and baseline experiments
Schutz, B. E.; Ho, C. S.; Abusali, P. A. M.; Tapley, B. D.
1990-01-01
CASA Uno data from sites distributed in longitude from Australia to Europe have been used to determine orbits of the GPS satellites. The characteristics of the orbits determined from double difference phase have been evaluated through comparisons of two-week solutions with one-week solutions and by comparisons of predicted and estimated orbits. Evidence of unmodeled effects is demonstrated, particularly associated with the orbit planes that experience solar eclipse. The orbit accuracy has been assessed through the repeatability of unconstrained estimated baseline vectors ranging from 245 km to 5400 km. Both the baseline repeatability and the comparison with independent space geodetic methods give results at the level of 1-2 parts in 100,000,000. In addition, the Mojave/Owens Valley (245 km) and Kokee Park/Ft. Davis (5409 km) estimates agree with VLBI and SLR to better than 1 part in 100,000,000.
Generating Animated Displays of Spacecraft Orbits
Candey, Robert M.; Chimiak, Reine A.; Harris, Bernard T.
2005-01-01
Tool for Interactive Plotting, Sonification, and 3D Orbit Display (TIPSOD) is a computer program for generating interactive, animated, four-dimensional (space and time) displays of spacecraft orbits. TIPSOD utilizes the programming interface of the Satellite Situation Center Web (SSCWeb) services to communicate with the SSC logic and database by use of the open protocols of the Internet. TIPSOD is implemented in Java 3D and effects an extension of the preexisting SSCWeb two-dimensional static graphical displays of orbits. Orbits can be displayed in any or all of the following seven reference systems: true-of-date (an inertial system), J2000 (another inertial system), geographic, geomagnetic, geocentric solar ecliptic, geocentric solar magnetospheric, and solar magnetic. In addition to orbits, TIPSOD computes and displays Sibeck's magnetopause and Fairfield's bow-shock surfaces. TIPSOD can be used by the scientific community as a means of projection or interpretation. It also has potential as an educational tool.
Hemangiopericitoma de órbita Orbital hemangiopericytoma
Directory of Open Access Journals (Sweden)
Ana Paula Ximenes Alves
2001-04-01
Full Text Available Objetivo: Descrever um raro caso de hemangiopericitoma orbital. Métodos: Relato de caso de associação entre hemangipericitoma orbital e blefaroptose. Resultados: A exérese da neoplasia normalizou o posicionamento palpebral. Conclusões: Lesões orbitais anteriores são causas de blefaroptose por compressão do músculo elevador palpebral.Purpose: To describe a rare case of orbital hemangiope- ricytoma. Methods: Case report of an association of blepha-roptosis with orbital hemangiopericytoma. Results: When the lesion was surgically removed the position of the upper eyelid returned to normal. Conclusions: Anterior orbital lesions can lead to blepharoptosis by compression of the levator palpebrae muscle.
Primary Orbital Chondromyxoid Fibroma: A Rare Case.
Mullen, Martin G; Somogyi, Marie; Maxwell, Sean P; Prabhu, Vikram; Yoo, David K
A 56-year-old male with history of chronic sinusitis was found to have a 3 cm left orbital lesion on CT. Subsequent MRI demonstrated a multilobulated enhancing soft tissue lesion at the superotemporal region of the left orbit. Initial biopsy was reported as a low-grade sarcoma. On further evaluation, a consensus was made that the lesion was likely a benign mixed mesenchymal type tumor but should nonetheless be surgically removed. Left lateral orbitotomy was performed which revealed a tumor originating in the lateral orbital bone with segments eroding through the wall of the orbit. Intraoperative frozen sections revealed myoepitheliod tissue with locally aggressive features and the tumor was completely removed. The final histopathologic analysis of the tissue was consistent with a chondromyxoid fibroma. Chondomyxoid fibroma is a rare entity in the orbital bones and is more commonly seen in long bones.
A conformal invariant model of localized spinning test particles
International Nuclear Information System (INIS)
Duval, C.; Centre National de la Recherche Scientifique, 13 - Marseille; Fliche, H.H.; Centre National de la Recherche Scientifique, 13 - Marseille
1977-02-01
A purely classical model of massless test particle with spin s is introduced as the dynamical system defined by the 10 dimensional 0(4,2) co-adjoint orbit with Casimir numbers (s 2 ,0,0). The Mathisson Papapetrou et al. equations of motion in a gravitational field are recovered, and moreover the particle appears to travel on null geodesics. Several implications are discussed
International Nuclear Information System (INIS)
Gaisser, T.K.; Shafi, Q.; Barr, S.M.; Seckel, D.; Rusjan, E.; Fletcher, R.S.
1991-01-01
This report discusses research of professor at Bartol research institute in the following general areas: particle phenomenology and non-accelerator physics; particle physics and cosmology; theories with higher symmetry; and particle astrophysics and cosmology
Metrics in Keplerian orbits quotient spaces
Milanov, Danila V.
2018-03-01
Quotient spaces of Keplerian orbits are important instruments for the modelling of orbit samples of celestial bodies on a large time span. We suppose that variations of the orbital eccentricities, inclinations and semi-major axes remain sufficiently small, while arbitrary perturbations are allowed for the arguments of pericentres or longitudes of the nodes, or both. The distance between orbits or their images in quotient spaces serves as a numerical criterion for such problems of Celestial Mechanics as search for common origin of meteoroid streams, comets, and asteroids, asteroid families identification, and others. In this paper, we consider quotient sets of the non-rectilinear Keplerian orbits space H. Their elements are identified irrespective of the values of pericentre arguments or node longitudes. We prove that distance functions on the quotient sets, introduced in Kholshevnikov et al. (Mon Not R Astron Soc 462:2275-2283, 2016), satisfy metric space axioms and discuss theoretical and practical importance of this result. Isometric embeddings of the quotient spaces into R^n, and a space of compact subsets of H with Hausdorff metric are constructed. The Euclidean representations of the orbits spaces find its applications in a problem of orbit averaging and computational algorithms specific to Euclidean space. We also explore completions of H and its quotient spaces with respect to corresponding metrics and establish a relation between elements of the extended spaces and rectilinear trajectories. Distance between an orbit and subsets of elliptic and hyperbolic orbits is calculated. This quantity provides an upper bound for the metric value in a problem of close orbits identification. Finally the invariance of the equivalence relations in H under coordinates change is discussed.
A Ballistic Limit Analysis Program for Shielding Against Micrometeoroids and Orbital Debris
Ryan, Shannon; Christiansen, Erie
2010-01-01
A software program has been developed that enables the user to quickly and simply perform ballistic limit calculations for common spacecraft structures that are subject to hypervelocity impact of micrometeoroid and orbital debris (MMOD) projectiles. This analysis program consists of two core modules: design, and; performance. The design module enables a user to calculate preliminary dimensions of a shield configuration (e.g., thicknesses/areal densities, spacing, etc.) for a ?design? particle (diameter, density, impact velocity, incidence). The performance module enables a more detailed shielding analysis, providing the performance of a user-defined shielding configuration over the range of relevant in-orbit impact conditions.
Influence of the spin-orbit coupling on nuclear superfluidity along the N=Z line
International Nuclear Information System (INIS)
Juillet, O.; Josse, S.
2000-01-01
We show that the spin-orbit potential of the nuclear mean field destroys isoscalar superfluid correlations in self-conjugate nuclei. Using group theory and boson mapping techniques on a Hamiltonian including single particle splittings and a SO ST (8) pairing interaction, we give analytical expression for the spin-orbit dependence of some N =Z properties such as the relative position of T = 0 and T = 1 states in odd-odd systems or double binding-energy differences of even-even nuclei. (authors)
Tunable rotary orbits of matter-wave nonlinear modes in attractive Bose-Einstein condensates
International Nuclear Information System (INIS)
He, Y J; Wang, H Z; Malomed, Boris A; Mihalache, Dumitru
2008-01-01
We demonstrate that by spatially modulating the Bessel optical lattice where a Bose-Einstein condensate is loaded, we get tunable rotary orbits of nonlinear lattice modes. We show that the radially expanding or shrinking Bessel lattice can drag the nonlinear localized modes to orbits of either larger or smaller radii and the rotary velocity of nonlinear modes can be changed accordingly. The localized modes can even be transferred to the Bessel lattice core when the localized modes' rotations are stopped. Effects beyond the quasi-particle approximation such as destruction of the nonlinear modes by nonadiabatic dragging are also explored
Colebeck, Amanda C.; Kase, Michael T.; Nichols, Cindy B.; Golden, Marjorie; Huryn, Joseph M.
2016-01-01
The basic objective in prosthetic restoration of confluent maxillary and orbital defects is to achieve a comfortable, cosmetically acceptable prosthesis that restores speech, deglutition, and mastication. It is a challenging task complicated by the size and shape of the defects. The maxillary obturator prosthesis often satisfies the objective of adequate deglutition; however, orbital defects that are not obturated in the medial septal or posterior walls allow air to escape, negatively impacting phonation. This article describes a technique to achieve favorable prosthetic rehabilitation in a patient with a maxillectomy and ipsilateral orbital exenteration. The prosthetic components include maxillary obturator, orbital conformer, and orbital prosthesis connected using rigid magnetic attachments. PMID:25953143
International Nuclear Information System (INIS)
Brion, C.E.; Hood, S.T.; Suzuki, I.H.; Weigold, E.
1980-02-01
The binding energy spectra and momentum distributions for the valence orbitals of HF and HCl have been obtained using (e,2e) spectroscopy with symmetric kinematics at 1200eV and 400eV. For HCl the strength of the innermost valence orbital (4sigma) is found to be significantly split among several ion states in the range 25eV to 41eV. The corresponding orbital in HF (2sigma) is however not significantly split among ion states. The measured momentum distributions are compared with the results of several calculatons of at least double zeta quality as well as with a one particle Green's function calculation of the generalized overlap amplitude. Agreement in shape is quite good for the innermost orbitals, but for the π and outer sigma orbitals of HF the momentum distributions calculated directly from the molecular orbitals are significantly more extended in momentum space than the measured distributions. The Green's function calculations give momentum distributions in good agreement with the data and pole strengths for transitions in qualitative agreement with the observed cross sections
Theory and design methods of special space orbits
Zhang, Yasheng; Zhou, Haijun
2017-01-01
This book focuses on the theory and design of special space orbits. Offering a systematic and detailed introduction to the hovering orbit, spiral cruising orbit, multi-target rendezvous orbit, initiative approaching orbit, responsive orbit and earth pole-sitter orbit, it also discusses the concept, theory, design methods and application of special space orbits, particularly the design and control method based on kinematics and astrodynamics. In addition the book presents the latest research and its application in space missions. It is intended for researchers, engineers and postgraduates, especially those working in the fields of orbit design and control, as well as space-mission planning and research.
Stable low-altitude orbits around Ganymede considering a disturbing body in a circular orbit
Cardoso dos Santos, J.; Carvalho, J. P. S.; Vilhena de Moraes, R.
2014-10-01
Some missions are being planned to visit Ganymede like the Europa Jupiter System Mission that is a cooperation between NASA and ESA to insert the spacecraft JGO (Jupiter Ganymede Orbiter) into Ganymedes orbit. This comprehension of the dynamics of these orbits around this planetary satellite is essential for the success of this type of mission. Thus, this work aims to perform a search for low-altitude orbits around Ganymede. An emphasis is given in polar orbits and it can be useful in the planning of space missions to be conducted around, with respect to the stability of orbits of artificial satellites. The study considers orbits of artificial satellites around Ganymede under the influence of the third-body (Jupiter's gravitational attraction) and the polygenic perturbations like those due to non-uniform distribution of mass (J_2 and J_3) of the main body. A simplified dynamic model for these perturbations is used. The Lagrange planetary equations are used to describe the orbital motion of the artificial satellite. The equations of motion are developed in closed form to avoid expansions in eccentricity and inclination. The results show the argument of pericenter circulating. However, low-altitude (100 and 150 km) polar orbits are stable. Another orbital elements behaved variating with small amplitudes. Thus, such orbits are convenient to be applied to future space missions to Ganymede. Acknowledgments: FAPESP (processes n° 2011/05671-5, 2012/12539-9 and 2012/21023-6).
Comparison of the orbital properties of Jupiter Trojan asteroids and Trojan dust
Liu, Xiaodong; Schmidt, Jrgen
2018-06-01
In a previous paper we simulated the orbital evolution of dust particles from the Jupiter Trojan asteroids ejected by the impacts of interplanetary particles, and evaluated their overall configuration in the form of dust arcs. Here we compare the orbital properties of these Trojan dust particles and the Trojan asteroids. Both Trojan asteroids and most of the dust particles are trapped in the Jupiter 1:1 resonance. However, for dust particles, this resonance is modified because of the presence of solar radiation pressure, which reduces the peak value of the semi-major axis distribution. We find also that some particles can be trapped in the Saturn 1:1 resonance and higher order resonances with Jupiter. The distributions of the eccentricity, the longitude of pericenter, and the inclination for Trojans and the dust are compared. For the Trojan asteroids, the peak in the longitude of pericenter distribution is about 60 degrees larger than the longitude of pericenter of Jupiter; in contrast, for Trojan dust this difference is smaller than 60 degrees, and it decreases with decreasing grain size. For the Trojan asteroids and most of the Trojan dust, the Tisserand parameter is distributed in the range of two to three.
International Nuclear Information System (INIS)
Roberts, W.W. Jr.; Stewart, G.R.
1987-01-01
The role of orbit crowding and cloud-cloud collisions in the formation of GMCs and their organization in global spiral structure is investigated. Both N-body simulations of the cloud system and a detailed analysis of individual particle orbits are used to develop a conceptual understanding of how individual clouds participate in the collective density response. Detailed comparisons are made between a representative cloud-particle simulation in which the cloud particles collide inelastically with one another and give birth to and subsequently interact with young star associations and stripped down simulations in which the cloud particles are allowed to follow ballistic orbits in the absence of cloud-cloud collisions or any star formation processes. Orbit crowding is then related to the behavior of individual particle trajectories in the galactic potential field. The conceptual picture of how GMCs are formed in the clumpy ISMs of spiral galaxies is formulated, and the results are compared in detail with those published by other authors. 68 references
Design of Compact Particle Detector System Using FPGA for Space Particle Environment Measurement
Directory of Open Access Journals (Sweden)
K. Ryu
2007-06-01
Full Text Available We have designed a high resolution proton and electron telescope for the detection of high energy particles, which constitute a major part of the space environment. The flux of the particles, in the satellite orbits, can vary abruptly according to the position and solar activities. In this study, a conceptual design of the detector, for adapting these variations with a high energy resolution, was made and the performance was estimated. In addition, a parallel processing algorithm was devised and embodied using FPGA for the high speed data processing, capable of detecting high flux without losing energy resolution, on board a satellite.
Reconstruction of Orbital Floor With Auricular Concha.
Seven, Ergin; Tellioglu, Ali Teoman; Inozu, Emre; Ozakpinar, Hulda Rifat; Horoz, Ugur; Eryilmaz, Avni Tolga; Karamursel, Sebat
2017-10-01
Orbital floor fractures of varying sizes commonly occur after orbital injuries and remain a serious challenge. Serious complications of such fractures include enopthalmos, restriction of extraocular movement, and diplopia. There is a dearth of literature that can be applied widely, easily, and successfully in all such situations, and therefore there is no consensus on the treatment protocol of this pathology yet. Autogenous grafts and alloplastic and allogenic materials with a wide variety of advantages and disadvantages have been discussed. The value of preoperative and postoperative ophthalmological examination should be standard of care in all orbital fracture patients. An ideal reconstructed orbital floor fracture should accelerate the restoration of orbital function with acceptable cosmetic results. Management parameters of orbital fractures such as timing of surgery, incision type, and implant materials, though widely discussed, remain controversial. In this study, 55 patients with orbital floor fractures surgically reconstructed with conchal cartilage grafts between 2008 and 2014 were retrospectively evaluated. Complications and long-time follow-up visit results have been reported with clinical and radiographic findings. The aim of this study was to present the authors' clinical experiences of reconstruction of blow-out fractures with auricular conchal graft and to evaluate the other materials available for use.
Distant retrograde orbits and the asteroid hazard
Perozzi, Ettore; Ceccaroni, Marta; Valsecchi, Giovanni B.; Rossi, Alessandro
2017-08-01
Distant Retrograde Orbits (DROs) gained a novel wave of fame in space mission design because of their numerous advantages within the framework of the US plans for bringing a large asteroid sample in the vicinity of the Earth as the next target for human exploration. DROs are stable solutions of the three-body problem that can be used whenever an object, whether of natural or artificial nature, is required to remain in the neighborhood of a celestial body without being gravitationally captured by it. As such, they represent an alternative option to Halo orbits around the collinear Lagrangian points L1 and L2. Also known under other names ( e.g., quasi-satellite orbits, cis-lunar orbits, family- f orbits) these orbital configurations found interesting applications in several mission profiles, like that of a spacecraft orbiting around the small irregularly shaped satellite of Mars Phobos or the large Jovian moon Europa. In this paper a basic explanation of the DRO dynamics is presented in order to clarify some geometrical properties that characterize them. Their accessibility is then discussed from the point of view of mission analysis under different assumptions. Finally, their relevance within the framework of the present asteroid hazard protection programs is shown, stressing the significant increase in warning time they would provide in the prediction of impactors coming from the direction of the Sun.
Objectives of a prospective Ukrainian orbiter mission to the moon
Shkuratov, Yu. G.; Lytvynenko, L. M.; Shulga, V. M.; Yatskiv, Ya. S.; Vidmachenko, A. P.; Kislyulk, V. S.
2003-06-01
Ukraine has launch vehicles that are able to deliver about 300 kg to lunar orbit. A future Ukrainian lunar program may propose a polar orbiter. This orbiter should fill principal information gaps in our knowledge about the Moon after the Clementine and Lunar Prospector missions and future missions like Smart-1, Lunar-A, and Selene. We consider that this can be provided by radar studies of the Moon with supporting optical photopolarimetric observations from lunar polar orbit. These experiments allow one to better understand global structure of the lunar surface at a wide range of scales, from microns to kilometers. We propose three instruments for the prospective lunar orbiter. They are a synthetic aperture imaging radar, ground-penetrating radar, and imaging UV-spectropolarimeter. The main purpose of the synthetic aperture imaging radar experiment is to study with high-resolution (50 m) permanently shadowed sites in the lunar polar regions. These sites are cold traps for volatiles, and have a potential for resource utilization. Possible presence of water ice in the regolith in the sites makes them interesting for long-term manned bases on the Moon. Radar and optical imaging and mapping of other interesting regions could be also planned. Multi-frequency, multi-polarization sounding of the lunar surface with ground-penetrating radar can provide data about internal structure of the lunar surface from meters to several hundred meters deep. The ground-penetrating radar can be used for measuring megaregolith properties, detection of cryptomaria, and studies of internal structure of the largest craters. Modest spatial resolution (50 m) of the imaging UV-spectropolarimeter should provide total coverage (or coverage of a large portion) of the lunar surface in oblique viewing at large phase angles. Polarization degree at large (>90°) phase angles bears information about characteristic size of the regolith particles. Additional experiments could use the synthetic aperture
The Double Star Orbit Initial Value Problem
Hensley, Hagan
2018-04-01
Many precise algorithms exist to find a best-fit orbital solution for a double star system given a good enough initial value. Desmos is an online graphing calculator tool with extensive capabilities to support animations and defining functions. It can provide a useful visual means of analyzing double star data to arrive at a best guess approximation of the orbital solution. This is a necessary requirement before using a gradient-descent algorithm to find the best-fit orbital solution for a binary system.
[A Case of an Orbital Angioleiomyoma].
Sato, Kohei; Ogawa, Yukari; Kinoshita, Keita; Takai, Hiroki; Hirai, Satoshi; Ishihara, Manabu; Hara, Keijiro; Toi, Hiroyuki; Matsubara, Shunji; Uno, Masaaki
2017-12-01
A 70-year-old woman presented with a 4-year history of painless conjunctival congestion and proptosis of the right eye. Computed tomography and magnetic resonance imaging revealed a 48-mm lesion in the right medial orbit. As the symptoms progressed, the tumor was resected by performing fronto-orbital craniotomy. Histopathological examination revealed a vascular tumor surrounded by smooth muscle fibers and immunohistochemistry demonstrated tumor positivity for smooth muscle actin and desmin. The tumor was diagnosed as an angioleiomyoma, and no recurrence has been observed as of 5 years postoperatively. Angioleiomyomas in the orbit are extremely rare;thus, we have reported this case with reference to the literature.
Viscosity of dilute suspensions of rodlike particles: A numerical simulation method
Yamamoto, Satoru; Matsuoka, Takaaki
1994-02-01
The recently developed simulation method, named as the particle simulation method (PSM), is extended to predict the viscosity of dilute suspensions of rodlike particles. In this method a rodlike particle is modeled by bonded spheres. Each bond has three types of springs for stretching, bending, and twisting deformation. The rod model can therefore deform by changing the bond distance, bond angle, and torsion angle between paired spheres. The rod model can represent a variety of rigidity by modifying the bond parameters related to Young's modulus and the shear modulus of the real particle. The time evolution of each constituent sphere of the rod model is followed by molecular-dynamics-type approach. The intrinsic viscosity of a suspension of rodlike particles is derived from calculating an increased energy dissipation for each sphere of the rod model in a viscous fluid. With and without deformation of the particle, the motion of the rodlike particle was numerically simulated in a three-dimensional simple shear flow at a low particle Reynolds number and without Brownian motion of particles. The intrinsic viscosity of the suspension of rodlike particles was investigated on orientation angle, rotation orbit, deformation, and aspect ratio of the particle. For the rigid rodlike particle, the simulated rotation orbit compared extremely well with theoretical one which was obtained for a rigid ellipsoidal particle by use of Jeffery's equation. The simulated dependence of the intrinsic viscosity on various factors was also identical with that of theories for suspensions of rigid rodlike particles. For the flexible rodlike particle, the rotation orbit could be obtained by the particle simulation method and it was also cleared that the intrinsic viscosity decreased as occurring of recoverable deformation of the rodlike particle induced by flow.
Bozkaya, Uǧur; Turney, Justin M.; Yamaguchi, Yukio; Schaefer, Henry F.; Sherrill, C. David
2011-09-01
Using a Lagrangian-based approach, we present a more elegant derivation of the equations necessary for the variational optimization of the molecular orbitals (MOs) for the coupled-cluster doubles (CCD) method and second-order Møller-Plesset perturbation theory (MP2). These orbital-optimized theories are referred to as OO-CCD and OO-MP2 (or simply "OD" and "OMP2" for short), respectively. We also present an improved algorithm for orbital optimization in these methods. Explicit equations for response density matrices, the MO gradient, and the MO Hessian are reported both in spin-orbital and closed-shell spin-adapted forms. The Newton-Raphson algorithm is used for the optimization procedure using the MO gradient and Hessian. Further, orbital stability analyses are also carried out at correlated levels. The OD and OMP2 approaches are compared with the standard MP2, CCD, CCSD, and CCSD(T) methods. All these methods are applied to H2O, three diatomics, and the O_4^+ molecule. Results demonstrate that the CCSD and OD methods give nearly identical results for H2O and diatomics; however, in symmetry-breaking problems as exemplified by O_4^+, the OD method provides better results for vibrational frequencies. The OD method has further advantages over CCSD: its analytic gradients are easier to compute since there is no need to solve the coupled-perturbed equations for the orbital response, the computation of one-electron properties are easier because there is no response contribution to the particle density matrices, the variational optimized orbitals can be readily extended to allow inactive orbitals, it avoids spurious second-order poles in its response function, and its transition dipole moments are gauge invariant. The OMP2 has these same advantages over canonical MP2, making it promising for excited state properties via linear response theory. The quadratically convergent orbital-optimization procedure converges quickly for OMP2, and provides molecular properties that
Energy Technology Data Exchange (ETDEWEB)
Granja, Carlos, E-mail: carlos.granja@utef.cvut.cz; Polansky, Stepan
2016-07-07
Detailed spatial- and time-correlated maps of the space radiation environment in Low Earth Orbit (LEO) are produced by the spacecraft payload SATRAM operating in open space on board the Proba-V satellite from the European Space Agency (ESA). Equipped with the hybrid semiconductor pixel detector Timepix, the compact radiation monitor payload provides the composition and spectral characterization of the mixed radiation field with quantum-counting and imaging dosimetry sensitivity, energetic charged particle tracking, directionality and energy loss response in wide dynamic range in terms of particle types, dose rates and particle fluxes. With a polar orbit (sun synchronous, 98° inclination) at the altitude of 820 km the payload samples the space radiation field at LEO covering basically the whole planet. First results of long-period data evaluation in the form of time-and spatially-correlated maps of total dose rate (all particles) are given.
Orbits 2nd order singularity-free solutions
Xu, Guochang
2014-01-01
In its 2nd edition, this book covers the theory of satellite orbits, derives the complete solutions of orbital disturbances, describes the algorithms of orbits determination and the applications of the theory to the phenomenon of physical satellite formation.
International Nuclear Information System (INIS)
Okun, L.B.
1991-01-01
This book presents papers on elementary particle physics, relations between various particles, and the connections between particle physics with other branches of physics. The papers include: Contemporary status and prospects of high-energy physics; Particle physics prospects; and High energy physics
International Nuclear Information System (INIS)
Anderson, K.A.; Chase, L.M.; Lin, R.P.; McCoy, J.E.; McGuire, R.E.
1974-01-01
The lunar particle shadows and boundary layer experiments aboard the Apollo 15 and 16 subsatellites and scientific reduction and analysis of the data to date are discussed with emphasis on four major topics: solar particles; interplanetary particle phenomena; lunar interactions; and topology and dynamics of the magnetosphere at lunar orbit. The studies of solar and interplanetary particles concentrated on the low energy region which was essentially unexplored, and the studies of lunar interaction pointed up the transition from single particle to plasma characteristics. The analysis concentrated on the electron angular distributions as highly sensitive indicators of localized magnetization of the lunar surface. Magnetosphere experiments provided the first electric field measurements in the distant magnetotail, as well as comprehensive low energy particle measurements at lunar distance
Mittal, K L
2015-01-01
The book provides a comprehensive and easily accessible reference source covering all important aspects of particle adhesion and removal. The core objective is to cover both fundamental and applied aspects of particle adhesion and removal with emphasis on recent developments. Among the topics to be covered include: 1. Fundamentals of surface forces in particle adhesion and removal.2. Mechanisms of particle adhesion and removal.3. Experimental methods (e.g. AFM, SFA,SFM,IFM, etc.) to understand particle-particle and particle-substrate interactions.4. Mechanics of adhesion of micro- and n
Phase-space curvature in spin-orbit-coupled ultracold atomic systems
Armaitis, J.; Ruseckas, J.; Anisimovas, E.
2017-04-01
We consider a system with spin-orbit coupling and derive equations of motion which include the effects of Berry curvatures. We apply these equations to investigate the dynamics of particles with equal Rashba-Dresselhaus spin-orbit coupling in one dimension. In our derivation, the adiabatic transformation is performed first and leads to quantum Heisenberg equations of motion for momentum and position operators. These equations explicitly contain position-space, momentum-space, and phase-space Berry curvature terms. Subsequently, we perform the semiclassical approximation and obtain the semiclassical equations of motion. Taking the low-Berry-curvature limit results in equations that can be directly compared to previous results for the motion of wave packets. Finally, we show that in the semiclassical regime, the effective mass of the equal Rashba-Dresselhaus spin-orbit-coupled system can be viewed as a direct effect of the phase-space Berry curvature.
Statistical properties of spectra in harmonically trapped spin-orbit coupled systems
DEFF Research Database (Denmark)
V. Marchukov, O.; G. Volosniev, A.; V. Fedorov, D.
2014-01-01
We compute single-particle energy spectra for a one-body Hamiltonian consisting of a two-dimensional deformed harmonic oscillator potential, the Rashba spin-orbit coupling and the Zeeman term. To investigate the statistical properties of the obtained spectra as functions of deformation, spin......-orbit and Zeeman strengths we examine the distributions of the nearest neighbor spacings. We find that the shapes of these distributions depend strongly on the three potential parameters. We show that the obtained shapes in some cases can be well approximated with the standard Poisson, Brody and Wigner...... distributions. The Brody and Wigner distributions characterize irregular motion and help identify quantum chaotic systems. We present a special choices of deformation and spin-orbit strengths without the Zeeman term which provide a fair reproduction of the fourth-power repelling Wigner distribution. By adding...
Orbital effect of the magnetic field in dynamical mean-field theory
Acheche, S.; Arsenault, L.-F.; Tremblay, A.-M. S.
2017-12-01
The availability of large magnetic fields at international facilities and of simulated magnetic fields that can reach the flux-quantum-per-unit-area level in cold atoms calls for systematic studies of orbital effects of the magnetic field on the self-energy of interacting systems. Here we demonstrate theoretically that orbital effects of magnetic fields can be treated within single-site dynamical mean-field theory with a translationally invariant quantum impurity problem. As an example, we study the one-band Hubbard model on the square lattice using iterated perturbation theory as an impurity solver. We recover the expected quantum oscillations in the scattering rate, and we show that the magnetic fields allow the interaction-induced effective mass to be measured through the single-particle density of states accessible in tunneling experiments. The orbital effect of magnetic fields on scattering becomes particularly important in the Hofstadter butterfly regime.
Review of particle properties. Particle Data Group
International Nuclear Information System (INIS)
1978-04-01
This review of the properties of leptons, mesons, and baryons is an updating of Review of Particle Properties, Particle Data Group [Rev. Mod. Phys. 48 (1976) No. 2, Part II; and Supplement, Phys. Lett. 68B (1977) 1]. Data are evaluated, listed, averaged, and summarized in tables. Numerous tables, figures, and formulae of interest to particle physicists are also included. A data booklet is available
Polar-Orbiting Satellite (POES) Images
National Oceanic and Atmospheric Administration, Department of Commerce — Visible and Infrared satellite imagery taken from camera systems or radiometer instruments on satellites in orbit around the poles. Satellite campaigns include...
Retrieval of RTG'S in earth orbit
International Nuclear Information System (INIS)
Raab, B.; Frieder, M.A.; Skrabek, A.
1982-01-01
Since 1961, some ten Radioisotope Thermoelectric Generators (RTG's) have been placed into a variety of spacecraft which are now in earth orbit. All of these spacecraft are in orbits with lifetimes in excess of 100 years and pose no risk. However, since most of these spacecraft are no longer being actively used, these may be subject to an active removal program to reduce the population of objects in space. Therefore, a study was undertaken to evaluate the feasibility of retrieving or disposing of spacecraft with RTGs on board. Intervention scenarios are developed and an orbital rendezvous vehicle is conceptualized. The costs of RTG retrieval are derived and compared to the costs of RTG disposal, i.e., boost to a higher, multi-millenium-lifetime orbit, and are found to be not significantly different
Amplitude damping channel for orbital angular momentum
CSIR Research Space (South Africa)
Dudley, Angela L
2010-03-01
Full Text Available Since the pioneering work on the entanglement of the orbital angular momentum (OAM) states of light, much attention has been devoted to the subject, with particular attention into the quantum aspects of information processing using OAM. Furthermore...
From Slater orbitals to Coulomb Sturmians
Indian Academy of Sciences (India)
The simple connection between the Slater orbitals, venerable in quantum chemistry, and ... Thanks to the growth of computing ... of classical mechanics for the motion of planets or pro- ... riments show that a ionized gas of H atom has a con-.
Cephalic Tetanus from Penetrating Orbital Wound
Directory of Open Access Journals (Sweden)
Eloïse Guyennet
2009-01-01
Full Text Available Tetanus is a neurologic disorder caused by tetanospasmin, a protein toxin elaborated by Clostridium tetani. Cephalic tetanus is a localized form of the disease causing trismus and dysfunction of cranial nerves. We report the case of a man who presented with facial trauma, complete ophthalmoplegia, exophthalmos, areactive mydriasis, and periorbital hematoma. An orbital CT revealed air bubbles in the right orbital apex. The patient was given a tetanus toxoid booster and antibiotherapy. After extraction of a wooden foreign body, the patient developed right facial nerve palsy, disorders of swallowing, contralateral III cranial nerve palsy, and trismus. Only one case of cephalic tetanus from penetrating orbital wound has been reported in literature 20 years ago. When a patient presents with an orbital wound with ophthalmoplegia and signs of anaerobic infection, cephalic tetanus should be ruled out.
POET: Planetary Orbital Evolution due to Tides
Penev, Kaloyan
2014-08-01
POET (Planetary Orbital Evolution due to Tides) calculates the orbital evolution of a system consisting of a single star with a single planet in orbit under the influence of tides. The following effects are The evolutions of the semimajor axis of the orbit due to the tidal dissipation in the star and the angular momentum of the stellar convective envelope by the tidal coupling are taken into account. In addition, the evolution includes the transfer of angular momentum between the stellar convective and radiative zones, effect of the stellar evolution on the tidal dissipation efficiency, and stellar core and envelope spins and loss of stellar convective zone angular momentum to a magnetically launched wind. POET can be used out of the box, and can also be extended and modified.
Hashimoto's thyroiditis, Sjogren's syndrome and orbital lymphoma.
Ko, G. T.; Chow, C. C.; Yeung, V. T.; Chan, H.; Cockram, C. S.
1994-01-01
A 69 year old Chinese housewife presented with periorbital puffiness, and dry eyes and mouth. Subsequent investigations confirmed the presence of Hashimoto's thyroiditis, Sjogren's syndrome and orbital lymphoma. This unusual combination is discussed with reference to previous publications.
Dealing with Uncertainties in Initial Orbit Determination
Armellin, Roberto; Di Lizia, Pierluigi; Zanetti, Renato
2015-01-01
A method to deal with uncertainties in initial orbit determination (IOD) is presented. This is based on the use of Taylor differential algebra (DA) to nonlinearly map the observation uncertainties from the observation space to the state space. When a minimum set of observations is available DA is used to expand the solution of the IOD problem in Taylor series with respect to measurement errors. When more observations are available high order inversion tools are exploited to obtain full state pseudo-observations at a common epoch. The mean and covariance of these pseudo-observations are nonlinearly computed by evaluating the expectation of high order Taylor polynomials. Finally, a linear scheme is employed to update the current knowledge of the orbit. Angles-only observations are considered and simplified Keplerian dynamics adopted to ease the explanation. Three test cases of orbit determination of artificial satellites in different orbital regimes are presented to discuss the feature and performances of the proposed methodology.
Environmental studies using earth orbital photography
Energy Technology Data Exchange (ETDEWEB)
Wobber, F J
1969-01-01
Orbital remote sensing, and particularly orbital photography, can provide immediately useful data for scientists familiar with applying aerial photographic techniques to environmental problems. Despite the expansion of analytical techniques in the earth sciences, the environmental data base has remained relatively static compared with increased information needs because of the difficulty of effective worldwide surveys and the high cost of timely data collection. Color, color infrared and black and white space photographs obtained incident to the Gemini and Apollo programs provide unique synoptic tools for analyzing modern environments and processes, and data that cannot be duplicated by aerial photographic mosaics. Principal advantages of orbital surveys include repetitious worldwide coverage promising environmental synthesis within the full spectrum of seasonal contrasts, and synoptic observations on a scale generally impossible from aircraft. The general categories of environmental data that can be extracted from orbital photography are summarized. 26 references, 37 figures, 3 tables.
Orbital-angular-momentum entanglement in turbulence
CSIR Research Space (South Africa)
Hamadou Ibrahim, A
2013-06-01
Full Text Available The turbulence-induced decay of orbital-angular-momentum (OAM) entanglement between two photons is investigated numerically and experimentally. To compare our resultswith previouswork,we simulate the turbulent atmosphere with a single phase screen...
Asteroid orbital error analysis: Theory and application
Muinonen, K.; Bowell, Edward
1992-01-01
We present a rigorous Bayesian theory for asteroid orbital error estimation in which the probability density of the orbital elements is derived from the noise statistics of the observations. For Gaussian noise in a linearized approximation the probability density is also Gaussian, and the errors of the orbital elements at a given epoch are fully described by the covariance matrix. The law of error propagation can then be applied to calculate past and future positional uncertainty ellipsoids (Cappellari et al. 1976, Yeomans et al. 1987, Whipple et al. 1991). To our knowledge, this is the first time a Bayesian approach has been formulated for orbital element estimation. In contrast to the classical Fisherian school of statistics, the Bayesian school allows a priori information to be formally present in the final estimation. However, Bayesian estimation does give the same results as Fisherian estimation when no priori information is assumed (Lehtinen 1988, and reference therein).
Satellite orbits in Levi-Civita space
Humi, Mayer
2018-03-01
In this paper we consider satellite orbits in central force field with quadratic drag using two formalisms. The first using polar coordinates in which the satellite angular momentum plays a dominant role. The second is in Levi-Civita coordinates in which the energy plays a central role. We then merge these two formalisms by introducing polar coordinates in Levi-Civita space and derive a new equation for satellite orbits which unifies these two paradigms. In this equation energy and angular momentum appear on equal footing and thus characterize the orbit by its two invariants. Using this formalism we show that equatorial orbits around oblate spheroids can be expressed analytically in terms of Elliptic functions. In the second part of the paper we derive in Levi-Civita coordinates a linearized equation for the relative motion of two spacecrafts whose trajectories are in the same plane. We carry out also a numerical verification of these equations.
Drift orbits in the TMX and MFTF-B tandem mirrors
International Nuclear Information System (INIS)
Byers, J.A.
1982-01-01
Drift orbits for the TMX and MFTF-B tandem-mirror designs are followed by using a long-thin expansion of the drift equations. Unexpected asymmetries in the field-line curvatures in the yin-yang end-mirror traps, caused by the transition coils between the solenoid and the yin-yang, result in an elliptical distortion of the drift surface with a/b=1.5 at most, a perhaps tolerable deviation from omnigenity. Yushmanov-trapped particles are no worse than the bulk hot particles. Finite-beta plasma fields, coupled to the asymmetric curvature, produce sizeable banana orbits with widths comparable to the plasma radius, but these orbits are possible for only a few of the particles. Details of the transition through resonance in the solenoid are shown, including the banana shapes of the drift surfaces and the disruption of the surface in the stochastic regime. The orbits in the original design for the A-cell of MFTF-B are the most extreme; in the vacuum fields they all have an extended peanut shape that finally closes only at about 3m. This shape is strongly non-omnigenous and suggests a hollow plasma-density profile. Finite-beta B vectorxnablaB drifts can help to minimize the radial extent of these orbits, but the strength of the vacuum curvatures makes omnigenity only marginally possible. Including B vectorxnablaphi drifts makes omnigenity even more unlikely for the ions, for which the B vectorxnablaB and B vectorxnablaphi drifts are of opposite sign, and conversely helps to omnigenize the drift surfaces of the ECRH 200-keV electrons. It is argued that not every class of particles can have good, i.e. near-omnigenous drifts, regardless of the ability of phi(r) to adjust to limit the radial extent of the orbits. This lack of omnigenity leaves one with no theoretical base for describing the MHD equilibrium in the original designs, but a new magnetic field design for MFTF-B A-cell has apparently completely restored omnigenous orbits. (author)
Orbit control on SPEAR: a progress report
International Nuclear Information System (INIS)
Corbett, W.J.; Keeley, D.
1994-01-01
In this paper, we report work on initial studies of the global feedback system for SPEAR. In particular, we describe components of a comprehensive accelerator simulation program used to assess the performance of harmonic and eigenvector orbit control algorithms. This program has also been used to choose new bpm sites, and can simulate the interaction between global and local orbit feedback systems. A prototype on-line version used for SPEAR is discussed. copyright 1994 American Institute of Physics
About counterintuitive orbital mixing and bond populations
International Nuclear Information System (INIS)
Jorge, F.E.; Giambiagi, M.; Giambiagi, M.S. de
1983-01-01
It is shown that negative bond and orbital populations may be avoided by the introduction of a weight factor in a bond index definition, together with a suitable parameterization. The negative bond populations found for first-row metal complexes need not be ascribed to counterintuitive orbital mixing but rather, essentially, to the equipartition of the charge distribution. Different definitions of the bond population are compared for ferrocene and the effects of some parameterizations are discussed. (Author) [pt
History of Satellite Orbit Determination at NSWCDD
2018-01-31
meeting of the Satellite Division of ION, Palm Springs, CA., 12–15 Sep 1995. Hughey, Raymond H., Jr., “ History of Mathematics and Computing Technology ...TR-17/229 HISTORY OF SATELLITE ORBIT DETERMINATION AT NSWCDD BY EVERETT R. SWIFT WARFARE SYSTEMS ENGINEERING AND INTEGRATION...AND SUBTITLE History of Satellite Orbit Determination at NSWCDD 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER
Equivelar toroids with few flag-orbits
Collins, José; Montero, Antonio
2018-01-01
An $(n+1)$-toroid is a quotient of a tessellation of the $n$-dimensional Euclidean space with a lattice group. Toroids are generalizations of maps in the torus on higher dimensions and also provide examples of abstract polytopes. Equivelar toroids are those that are induced by regular tessellations. In this paper we present a classification of equivelar $(n+1)$-toroids with at most $n$ flag-orbits; in particular, we discuss a classification of $2$-orbit toroids of arbitrary dimension.
Orbiting transmission source for positron tomography
International Nuclear Information System (INIS)
Huesman, R.H.; Derenzo, S.E.; Cahoon, J.L.; Geyer, A.B.; Moses, W.W.; Uber, D.C.; Vuletich, T.; Budinger, T.F.
1988-01-01
Accidental suppression and effective data rates have been measured for the orbiting transmission source as implemented in the Donner 600-Crystal Positron Tomograph. A mechanical description of the orbiting source and a description of the electronics used to discard scattered and accidental events is included. Since accidental coincidences were the rate-limiting factor in transmission data acquisition, the new method allows us to acquire sufficient transmission data in a shorter time with a more active transmission source
Servicing communication satellites in geostationary orbit
Russell, Paul K.; Price, Kent M.
1990-01-01
The econmic benefits of a LEO space station are quantified by identifying alternative operating scenarios utilizing the space station's transportation facilities and assembly and repair facilities. Particular consideration is given to the analysis of the impact of on-orbit assembly and servicing on a typical communications satellite is analyzed. The results of this study show that on-orbit servicing can increase the internal rate of return by as much as 30 percent.
Orbital infarction in sickle cell disease
International Nuclear Information System (INIS)
Wolff, M.H.; Sty, J.R.
1985-01-01
Bone infarction is common in sickle cell disease; however, involvement of the orbit is not. Only four cases have been reported in the English literature. We describe a patient who presented with headache, proptosis and lid edema due to infarction of the sphenoid bone. The combination of radionuclide bone imaging and computed tomography (CT) of the orbit were useful in differentiating bone infarction from other etiologies of proptosis. (orig.)
Numerical code to determine the particle trapping region in the LISA machine
International Nuclear Information System (INIS)
Azevedo, M.T. de; Raposo, C.C. de; Tomimura, A.
1984-01-01
A numerical code is constructed to determine the trapping region in machine like LISA. The variable magnetic field is two deimensional and is coupled to the Runge-Kutta through the Tchebichev polynomial. Various particle orbits including particle interactions were analysed. Beside this, a strong electric field is introduced to see the possible effects happening inside the plasma. (Author) [pt
Olmstead, D.
1985-01-01
The 1985 Space WARC will examine and potentially modify the current geostationary orbit spectrum resource allocation methodology. Discussions in this international political environment could likely associate the geostationary orbital debris issue with the politicized issue of orbit spectrum allocation.
Orbital forcing of climate 1.4 billion years ago
DEFF Research Database (Denmark)
Zhang, Shuichang; Wang, Xiaomei; Hammarlund, Emma U
2015-01-01
Fluctuating climate is a hallmark of Earth. As one transcends deep into Earth time, however, both the evidence for and the causes of climate change become difficult to establish. We report geochemical and sedimentological evidence for repeated, short-term climate fluctuations from the exceptionally...... well-preserved ∼1.4-billion-year-old Xiamaling Formation of the North China Craton. We observe two patterns of climate fluctuations: On long time scales, over what amounts to tens of millions of years, sediments of the Xiamaling Formation record changes in geochemistry consistent with long-term changes...... reflect what appear to be orbitally forced changes in wind patterns and ocean circulation as they influenced rates of organic carbon flux, trace metal accumulation, and the source of detrital particles to the sediment....
Plasma flow measurements in a simulated low earth orbit plasma
International Nuclear Information System (INIS)
Gabriel, S.B.; Mccoy, J.E.; Carruth, M.R. Jr.
1982-01-01
The employment of large, higher power solar arrays for space operation has been considered, taking into account a utilization of high operating voltages. In connection with the consideration of such arrays, attention must be given to the fact that the ambient environment of space contains a tenuous low energy plasma which can interact with the high voltage array causing power 'leakage' and arcing. An investigation has been conducted with the aim to simulate the behavior of such an array in low-earth-orbit (LEO). During the experiments, local concentrations of the 'leakage' current were observed when the panel was at a high voltage. These concentrations could overload or damage a small area of cells in a large string. It was hypothesized that this effect was produced by electrostatic focusing of the particles by the sheath fields. To verify this experimentally, an end-effect Langmuir probe was employed. The obtained results are discussed
Nonrelativistic equations of motion for particles with arbitrary spin
International Nuclear Information System (INIS)
Fushchich, V.I.; Nikitin, A.G.
1981-01-01
First- and second-order Galileo-invariant systems of differential equations which describe the motion of nonrelativistic particles of arbitrary spin are derived. The equations can be derived from a Lagrangian and describe the dipole, quadrupole, and spin-orbit interaction of the particles with an external field; these interactions have traditionally been regarded as purely relativistic effects. The problem of the motion of a nonrelativistic particle of arbitrary spin in a homogeneous magnetic field is solved exactly on the basis of the obtained equations. The generators of all classes of irreducible representations of the Galileo group are found
Relativistic motion of particle in photogravitational field of star
International Nuclear Information System (INIS)
Zubko, O.L.
2014-01-01
Relativistic motion of particle in photogravitational field of star has been considered at different levels. It is shown that taking into account direct light pressure, elliptical orbit of the particle increases in sizes. Taking into account longitudinal Doppler effect and aberration of light leads to the motion of the particle by decreasing in size ellipse, which also has decreasing and eccentricity. Taking into account forces proportional to v 1 2 /c 2 leads to a faster reduction of the ellipse and its eccentricity. (authors)
Motion of charged test particles in Reissner-Nordstroem spacetime
International Nuclear Information System (INIS)
Pugliese, Daniela; Quevedo, Hernando; Ruffini, Remo
2011-01-01
We investigate the circular motion of charged test particles in the gravitational field of a charged mass described by the Reissner-Nordstroem spacetime. We study in detail all the spatial regions where circular motion is allowed around either black holes or naked singularities. The effects of repulsive gravity are discussed by finding all the circles at which a particle can have vanishing angular momentum. We show that the geometric structure of stable accretion disks, made of only test particles moving along circular orbits around the central body, allows us to clearly distinguish between black holes and naked singularities.
Charged particle beam monitoring by means of synchrotron radiation
International Nuclear Information System (INIS)
Panasyuk, V.S.; Anevskij, S.I.
1984-01-01
Optical methods for monitoring the number of accelerated electrons and electron energy by means of beam synchrotron radiation (SR) as well as peculiarities of SR characteristics of beams with a small radius of the orbit are considered. Optical methods for charged particle beam monitoring are shown to ensure operative and precise monitoring the number of particles and particle energy. SR sources with large axial dimensions of an electron beam have specific spectral angular and polarization characteristics. If electron angular distribution at deflection from the median plane is noticeably wider than angular distribution of SR of a certain electron, relative SR characteristics of these soUrces are calculated with high accuracy
Orbital lymphoma masquerading as thyroid ophthalmopathy.
Boyce, P J
1998-10-01
Lymphoid tumors are known to originate within the lacrimal gland and orbital fat. Ocular findings commonly seen are a palpable mass with proptosis and downward displacement of the globe. Graves' ophthalmopathy is the most common orbital pathology occurring in the general population. Signs and symptoms of Graves' ophthalmopathy, such as unilateral or bilateral proptosis, double vision, limitation of movement of the extraocular muscles, are not specific for this condition. A 57-year-old man came to us with a chief symptom of "eye swelling" for the last 3 years. He had been diagnosed with hyperthyroidism and had received three surgical procedures for orbital decompression. Clinical findings included limitation of upward and downward gaze, exophthalmometry readings of 30 1/2 mm O.D. and 31 mm O.S. (with a base of 112), and profound proptosis with fatty tissue prolapse. Subsequent thyroid testing revealed euthyroid status and computed tomography scan revealed orbital lymphoma. Orbital involvement from a malignant nodular histiocytic lymphoma resulted in a proptosis similar to that observed in Graves' ophthalmopathy. This very unusual presentation of orbital lymphoma mimicked Graves' disease so closely that the true cause was overlooked. This case emphasizes the need to include space-occupying lesions in the differential diagnosis of proptosis and gaze restrictions. The disease process and controversial management strategies are discussed.
Orbit Feedback Operation with RCBX (MD 1209)
Wenninger, Jorg; Nisbet, David; Ponce, Laurette; Louro Alves, Diogo Miguel; CERN. Geneva. ATS Department
2017-01-01
The LHC Orbit Feedback (OFB) is able to drive any orbit corrector circuit (COD) to steer the LHC orbit. But during the first feedback tests in 2010, all attempts to use the common triplet orbit correctors (MCBX) failed because the QPS system installed to protect those magnets triggered power aborts as soon as the OFB steered the beam with those CODs. The reason was most likely the violation of the RCBX circuit acceleration limits. For this reason the MCBX orbit correctors were never driven by the OFB in regular operation. Although the performance of the OFB is generally excellent, the quality of the beam steering around IRs could be improved if the OFB could correct the orbit with the MCBX to counteract locally triplet quadrupole movements. The aim of this MD was to make a new attempt to use the MCBX in the OFB. The test was successful at injection (no circuit trip) and failed during the ramp (QPS power abort). The PC voltages and QPS Ures signals revealed the presence of voltage spikes with a period of 10~s...
Radiotherapy of lymphoid diseases of the orbit
International Nuclear Information System (INIS)
Austin-Seymour, M.M.; Donaldson, S.S.; Egbert, P.R.; McDougall, I.R.; Kriss, J.P.
1985-01-01
Thirty-two patients with orbital pseudotumor (18), reactive lymphoid hyperplasia (2), atypical lymphoid infiltrate (4) or malignant lymphoma (8) were treated in the Division of Radiation Therapy at Stanford University between January 1973 and May 1983. Of the 20 patients with pseudotumor or reactive lymphoid hyperplasia, 10 had unilateral lesions and 10 had bilateral lesions. Biopsy samples were obtained in 15 patients; in five patients with bilateral disease the diagnosis was made on the basis of computed tomography (CT) and clinical findings. The majority of patients were referred because of disease refractory to treatment with corticosteroids. The patients were given a mean dose of 2360 rad using complex, individualized megavoltage techniques including lens shielding. Radiotherapy was well tolerated with no significant acute or late complications. Fifteen patients had complete resolution of symptoms after treatment; five had continued symptoms. Of the 12 patients with malignant lymphoma or atypical lymphoid infiltrate, four had systemic lymphoma with orbital involvement and eight had orbital involvement only. A mean dose of 3625 rad was delivered to the orbit only. Most of the patients received complex megavoltage treatment using bolus. All patients in this group had a complete response and local control. Two patients developed cataracts. Carefullly planned orbital radiotherapy provides local control without symptomatic sequelae for orbital masses ranging from pseudotumor to malignant lymphoma
Edwards, C. S.; Piqueux, S.; Hamilton, V. E.; Fergason, R. L.; Herkenhoff, K. E.; Vasavada, A. R.; Sacks, L. E.; Lewis, K. W.; Smith, M. D.
2017-12-01
The surface of Mars has been characterized using orbital thermal infrared observations from the time of the Mariner 9 and Viking missions. More recent observations from missions such as the Thermal Emission Spectrometer onboard the Mars Global Surveyor and the Thermal Emission Imaging System (THEMIS) instrument onboard the 2001 Mars Odyssey orbiter have continued to expand global coverage at progressively higher resolution. THEMIS has been producing 100 m/pixel thermal infrared data with nearly global coverage of the surface for >15 years and has enabled new investigations that successfully link outcrop-scale information to physical properties of the surface. However, significant discrepancies between morphologies and interpreted surface properties derived from orbital thermal measurements remain, requiring a robust link to direct surface measurements. Here, we compare the thermophysical properties and particle sizes derived from the Mars Science Laboratory (MSL) rover's Ground Temperature Sensor (GTS), to those derived orbitally from THEMIS, ultimately linking these measurements to ground truth particle sizes determined from Mars Hand Lens Imager (MAHLI) images. We focus on the relatively homogenous Bagnold dunes, specifically Namib dune, and in general find that all three datasets report consistent particle sizes for the Bagnold dunes ( 110-350 µm, and are within measurement and model uncertainties), indicating that particles sizes of homogeneous materials determined from thermal measurements are reliable. In addition, we assess several potentially significant effects that could influence the derived particle sizes, including: 1) fine-scale (cm-m scale) ripples, and 2) thin (mm-cm) layering of indurated/armored materials. To first order, we find that small scale ripples and thin layers do not significantly affect the determination of bulk thermal inertia determined from orbit. However, a layer of coarser/indurated material and/or fine-scale layering does change
Theoretical and experimental studies of the orbit expansion effect
International Nuclear Information System (INIS)
Glazov, A.A.; Denisov, Yu.N.; Dmitrievskij, V.P.
1985-01-01
Calculation and experiment results of investigations on the orbit expansion effect in the periodic magnetic structures are considered. Experiments, conducted with the use of ring cyclotron electron model, have shown, that the orbit expansion effect leads to the beam cross section radial size increase. This phenomenon was eliminated through the introduction of correction coils, which provide for the required low harmonic phase and value change in the whole acceleration area. Energy spread leads to the spreading of beam in the expansion area. Numeric calculations show, that for the electron model used the relative energy spread must be less than 10 -3 . The conclusion is drawn, that the only real possibility to obtain an accelerated beam with such an energy spread is to perform the ''flat-top'' regime. Equipment for cyclotron electron model RF supply is developed and produced to realise this regime. Particle dinamics calculation in the ''flat-top'' regime and the first experiments have shown, that acceleration asymmetry leads to the rapid coherent oscillation swing in the centre up to the amplitude of 6-7 sm
Orbital free molecular dynamics; Approche sans orbitale des plasmas denses
Energy Technology Data Exchange (ETDEWEB)
Lambert, F
2007-08-15
The microscopic properties of hot and dense plasmas stay a field essentially studied thanks to classical theories like the One Component Plasma, models which rely on free parameters, particularly ionization. In order to investigate these systems, we have used, in this PhD work, a semi-classical model, without free parameters, that is based on coupling consistently classical molecular dynamics for the nuclei and orbital free density functional theory for the electrons. The electronic fluid is represented by a free energy entirely determined by the local density. This approximation was validated by a comparison with an ab initio technique, quantum molecular dynamics. This one is identical to the previous except for the description of the free energy that depends on a quantum-independent-particle model. Orbital free molecular dynamics was then used to compute equation of state of boron and iron plasmas in the hot and dense regime. Furthermore, comparisons with classical theories were performed on structural and dynamical properties. Finally, equation of state and transport coefficients mixing laws were studied by direct simulation of a plasma composed of deuterium and copper. (author)
Examination of returned solar-max surfaces for impacting orbital debris and meteoroids
Kessler, D. J.; Zook, H. A.; Potter, A. E.; Mckay, D. S.; Clanton, U. S.; Warren, J. L.; Watts, L. A.; Schultz, R. A.; Schramm, L. S.; Wentworth, S. J.
1985-01-01
Previous theoretical studies predicted that in certain regions of earth orbit, the man-made earth orbiting debris environment will soon exceed the interplanetary meteoroid environment for sizes smaller than 1 cm. The surfaces returned from the repaired Solar Max Mission (SMM) by STS 41-C on April 12, 1984, offered an excellent opportunity to examine both the debris and meteoroid environments. To date, approximately 0.7 sq. met. of the thermal insulation and 0.05 sq. met of the aluminum louvers have been mapped by optical microscope for crater diameters larger than 40 microns. Craters larger in diameter than about 100 microns found on the initial 75 micron thick Kapton first sheet on the MEB (Main Electronics Box) blanket are actually holes and constitute perforations through that blanket. The following populations have been found to date in impact sites on these blankets: (1) meteoritic material; (2) thermal paint particles; (3) aluminum droplets; and (4) waste particles.
Influence of a superconducting lead on orbital entanglement production in chaotic cavities
International Nuclear Information System (INIS)
Rodriguez-Perez, Sergio; Novaes, Marcel
2015-01-01
We study orbital entanglement production in a chaotic cavity connected to four single-channel normal metal leads and one superconducting lead, assuming the presence of time-reversal symmetry and within a random matrix theory approach. The scattered state of two incident electrons is written as the superposition of several two-outgoing quasi-particle components, four of which are orbitally entangled in a left-right bipartition. We calculate numerically the mean value of the squared norm of each entangled component, as functions of the number of channels in the superconducting lead. Its behavior is explained as resulting from the proximity effect. We also study statistically the amount of entanglement carried by each pair of outgoing quasi-particles. When the influence of the superconductor is more intense, the device works as an entangler of electron-hole pairs, and the average entanglement is found to be considerably larger than that obtained without the superconducting lead. (author)
Influence of a superconducting lead on orbital entanglement production in chaotic cavities
Energy Technology Data Exchange (ETDEWEB)
Rodriguez-Perez, Sergio [Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN (Brazil). Escola de Ciencias e Tecnologia; Novaes, Marcel, E-mail: sergio.rodriguez@ect.ufrn.br [Universidade Federal de Uberlandia (UFU), MG (Brazil). Instituto de Fisica
2015-10-15
We study orbital entanglement production in a chaotic cavity connected to four single-channel normal metal leads and one superconducting lead, assuming the presence of time-reversal symmetry and within a random matrix theory approach. The scattered state of two incident electrons is written as the superposition of several two-outgoing quasi-particle components, four of which are orbitally entangled in a left-right bipartition. We calculate numerically the mean value of the squared norm of each entangled component, as functions of the number of channels in the superconducting lead. Its behavior is explained as resulting from the proximity effect. We also study statistically the amount of entanglement carried by each pair of outgoing quasi-particles. When the influence of the superconductor is more intense, the device works as an entangler of electron-hole pairs, and the average entanglement is found to be considerably larger than that obtained without the superconducting lead. (author)
Scattering resonances in a low-dimensional Rashba-Dresselhaus spin-orbit coupled quantum gas
Wang, Su-Ju; Blume, D.
2017-04-01
Confinement-induced resonances allow for the tuning of the effective one-dimensional coupling constant. When the scattering state associated with the ground transverse mode is brought into resonance with the bound state attached to the energetically excited transverse modes, the atoms interact through an infinitely strong repulsion. This provides a route to realize the Tonks-Girardeau gas. On the other hand, the realization of synthetic gauge fields in cold atomic systems has attracted a lot of attention. For instance, bound-state formation is found to be significantly modified in the presence of spin-orbit coupling in three dimensions. This motivates us to study ultracold collisions between two Rashba-Dresselhaus spin-orbit coupled atoms in a quasi-one-dimensional geometry. We develop a multi-channel scattering formalism that accounts for the external transverse confinement and the spin-orbit coupling terms. The interplay between these two single-particle terms is shown to give rise to new scattering resonances. In particular, it is analyzed what happens when the scattering energy crosses the various scattering thresholds that arise from the single-particle confinement and the spin-orbit coupling. Support by the NSF is gratefully acknowledged.
Orbital and epicyclic frequencies around neutron and strange stars in R{sup 2} gravity
Energy Technology Data Exchange (ETDEWEB)
Staykov, Kalin V., E-mail: kstaykov@phys.uni-sofia.bg [Department of Theoretical Physics, Faculty of Physics, Sofia University, 1164, Sofia (Bulgaria); Doneva, Daniela D., E-mail: daniela.doneva@uni-tuebingen.de [Theoretical Astrophysics, Eberhard Karls University of Tübingen, 72076, Tübingen (Germany); INRNE-Bulgarian Academy of Sciences, 1784, Sofia (Bulgaria); Yazadjiev, Stoytcho S., E-mail: yazad@phys.uni-sofia.bg [Department of Theoretical Physics, Faculty of Physics, Sofia University, 1164, Sofia (Bulgaria); Theoretical Astrophysics, Eberhard Karls University of Tübingen, 72076, Tübingen (Germany)
2015-12-21
According to various models, the orbital and the epicyclic frequencies of particles moving on a circular orbit around compact objects are related to the quasi-periodic oscillations observed in the X-ray flux of some pulsars or black hole candidates. It is expected that they originate from the inner edge of the accretion discs, deep into the gravitational field of the compact objects. Considering the planned new generation X-ray timing observatories with large collective areas, the quasi-periodic oscillations might be an excellent tool for testing gravity in strong field regime and, respectively, alternative gravitational theories. We examine the orbital and the epicyclic frequencies of a particle moving on a circular orbit around neutron or strange stars in R{sup 2} gravity. The case of slow rotation is considered too. The R{sup 2} gravity results are compared to the general relativistic case. We comment on the deviations from general relativity, as well as the deviations due to rotation in both theories.
Orbital and epicyclic frequencies around neutron and strange stars in R{sup 2} gravity
Energy Technology Data Exchange (ETDEWEB)
Staykov, Kalin V. [Sofia University, Department of Theoretical Physics, Faculty of Physics, Sofia (Bulgaria); Doneva, Daniela D. [Eberhard Karls University of Tuebingen, Theoretical Astrophysics, Tuebingen (Germany); INRNE-Bulgarian Academy of Sciences, Sofia (Bulgaria); Yazadjiev, Stoytcho S. [Sofia University, Department of Theoretical Physics, Faculty of Physics, Sofia (Bulgaria); Eberhard Karls University of Tuebingen, Theoretical Astrophysics, Tuebingen (Germany)
2015-12-15
According to various models, the orbital and the epicyclic frequencies of particles moving on a circular orbit around compact objects are related to the quasi-periodic oscillations observed in the X-ray flux of some pulsars or black hole candidates. It is expected that they originate from the inner edge of the accretion discs, deep into the gravitational field of the compact objects. Considering the planned new generation X-ray timing observatories with large collective areas, the quasi-periodic oscillations might be an excellent tool for testing gravity in strong field regime and, respectively, alternative gravitational theories. We examine the orbital and the epicyclic frequencies of a particle moving on a circular orbit around neutron or strange stars in R{sup 2} gravity. The case of slow rotation is considered too. The R{sup 2} gravity results are compared to the general relativistic case. We comment on the deviations from general relativity, as well as the deviations due to rotation in both theories. (orig.)
The current status of development of the electron and proton telescope for Solar Orbiter
Energy Technology Data Exchange (ETDEWEB)
Steinhagen, Jan; Kulkarni, Shrinivasrao; Boden, Sebastian; Martin-Garcia, Cesar; Boettcher, Stephan; Schuster, Bjoern; Seimetz, Lars; Wimmer-Schweingruber, Robert F. [IEAP, Christian-Albrechts-Universitaet zu Kiel (Germany)
2013-07-01
ESA's Solar Orbiter mission, scheduled for launch in January 2017, will study how the sun creates the inner heliosphere. Therefore, the spacecraft will perform in situ and remote sensing measurements of the sun on a high inclination orbit with a perihelion of about 60 solar radii, making it possible to observe the poles of the sun from nearby. The Energetic Particle Detector suite on-board of Solar Orbiter will measure particles of a wide energy range and from multiple directions. One of the important sensors of the EPD suite is the Electron and Proton Telescope. It consists of two antiparallel telescopes with two silicon detectors respectively and is designed to detect electrons between 20 - 400 keV and protons from 20 keV to 7 MeV. EPT relies on a magnet/foil technique to discriminate between electrons and protons. Its design is driven by mass allocation, the thermal environment, power consumption and electronic noise; especially the magnet system must guarantee stray fields low enough to be compliant with the Solar Orbiter EMC requirements. Here, we present the current status of the Structural/Thermal Model and Engineering Model assembly as well as the integration and testing of the prototype.
An analysis of the orbital distribution of solid rocket motor slag
Horstman, Matthew F.; Mulrooney, Mark
2009-01-01
The contribution by solid rocket motors (SRMs) to the orbital debris environment is potentially significant and insufficiently studied. Design and combustion processes can lead to the emission of enough by-products to warrant assessment of their contribution to orbital debris. These particles are formed during SRM tail-off, or burn termination, by the rapid solidification of molten Al2O3 slag accumulated during the burn. The propensity of SRMs to generate particles larger than 100μm raises concerns regarding the debris environment. Sizes as large as 1 cm have been witnessed in ground tests, and comparable sizes have been estimated via observations of sub-orbital tail-off events. Utilizing previous research we have developed more sophisticated size distributions and modeled the time evolution of resultant orbital populations using a historical database of SRM launches, propellant, and likely location and time of tail-off. This analysis indicates that SRM ejecta is a significant component of the debris environment.
Stochastic orbital migration of small bodies in Saturn's rings
Rein, H.; Papaloizou, J. C. B.
2010-12-01
Many small moonlets that create propeller structures have been found in Saturn's rings by the Cassini spacecraft. We study the dynamical evolution of such 20-50 m sized bodies, which are embedded in Saturn's rings. We estimate the importance of various interaction processes with the ring particles on the moonlet's eccentricity and semi-major axis analytically. For low ring surface densities, the main effects on the evolution of the eccentricity and the semi-major axis are found to be caused by collisions and the gravitational interaction with particles in the vicinity of the moonlet. For high surface densities, the gravitational interaction with self-gravity wakes becomes important. We also perform realistic three-dimensional, collisional N-body simulations with up to a quarter of a million particles. A new set of pseudo shear periodic boundary conditions is used, which reduces the computational costs by an order of magnitude compared to previous studies. Our analytic estimates are confirmed to within a factor of two. On short timescales the evolution is always dominated by stochastic effects caused by collisions and gravitational interaction with self-gravitating ring particles. These result in a random walk of the moonlet's semi-major axis. The eccentricity of the moonlet quickly reaches an equilibrium value owing to collisional damping. The average change in semi-major axis of the moonlet after 100 orbital periods is 10-100m. This translates to an offset in the azimuthal direction of several hundred kilometres. We expect that such a shift is easily observable. Two movies are only available in electronic form at http://www.aanda.org
Small-action Particles in a Tokamak in the Presence of an n = 1 Mode
International Nuclear Information System (INIS)
White, R.B.; Lutsenko, V.V.; Kolesnichenko, Ya. I.; Yakovenko, Yu. V.
1999-01-01
It is found that an m = n = 1 mode with the amplitude exceeding a certain threshold can lead to stochastic motion of energetic ions in tokamaks, the large orbit width particles (potatoes) being most easily affected. An n = 1 mode can redistribute particles also in the absence of stochasticity but only when the perturbation is quickly switched on/off, e.g., due to sawtooth crash. In the latter case, the perturbation results in regular motion of particles around a certain helical orbit, at which a resonance driven by the mode but having no amplitude threshold takes place
On the lunar node resonance of the orbital plane evolution of the Earth's satellite orbits
Zhu, Ting-Lei
2018-06-01
This paper aims to investigate the effects of lunar node resonance on the circular medium Earth orbits (MEO). The dynamical model is established in classical Hamiltonian systems with the application of Lie transform to remove the non-resonant terms. Resonant condition, stability and phase structures are studied. The lunar node resonance occurs when the secular changing rates of the orbital node (with respect to the equator) and the lunar node (with respect to the ecliptic) form a simple integer ratio. The resonant conditions are satisfied for both inclined and equatorial orbits. The orbital plane would have long period (with typical timescales of several centuries) fluctuation due to the resonance.
Burn Delay Analysis of the Lunar Orbit Insertion for Korea Pathfinder Lunar Orbiter
Bae, Jonghee; Song, Young-Joo; Kim, Young-Rok; Kim, Bangyeop
2017-12-01
The first Korea lunar orbiter, Korea Pathfinder Lunar Orbiter (KPLO), has been in development since 2016. After launch, the KPLO will execute several maneuvers to enter into the lunar mission orbit, and will then perform lunar science missions for one year. Among these maneuvers, the lunar orbit insertion (LOI) is the most critical maneuver because the KPLO will experience an extreme velocity change in the presence of the Moon’s gravitational pull. However, the lunar orbiter may have a delayed LOI burn during operation due to hardware limitations and telemetry delays. This delayed burn could occur in different captured lunar orbits; in the worst case, the KPLO could fly away from the Moon. Therefore, in this study, the burn delay for the first LOI maneuver is analyzed to successfully enter the desired lunar orbit. Numerical simulations are performed to evaluate the difference between the desired and delayed lunar orbits due to a burn delay in the LOI maneuver. Based on this analysis, critical factors in the LOI maneuver, the periselene altitude and orbit period, are significantly changed and an additional delta-V in the second LOI maneuver is required as the delay burn interval increases to 10 min from the planned maneuver epoch.
Effects of DeOrbitSail as applied to Lifetime predictions of Low Earth Orbit Satellites
Afful, Andoh; Opperman, Ben; Steyn, Herman
2016-07-01
Orbit lifetime prediction is an important component of satellite mission design and post-launch space operations. Throughout its lifetime in space, a spacecraft is exposed to risk of collision with orbital debris or operational satellites. This risk is especially high within the Low Earth Orbit (LEO) region where the highest density of space debris is accumulated. This paper investigates orbital decay of some LEO micro-satellites and accelerating orbit decay by using a deorbitsail. The Semi-Analytical Liu Theory (SALT) and the Satellite Toolkit was employed to determine the mean elements and expressions for the time rates of change. Test cases of observed decayed satellites (Iridium-85 and Starshine-1) are used to evaluate the predicted theory. Results for the test cases indicated that the theory fitted observational data well within acceptable limits. Orbit decay progress of the SUNSAT micro-satellite was analysed using relevant orbital parameters derived from historic Two Line Element (TLE) sets and comparing with decay and lifetime prediction models. This paper also explored the deorbit date and time for a 1U CubeSat (ZACUBE-01). The use of solar sails as devices to speed up the deorbiting of LEO satellites is considered. In a drag sail mode, the deorbitsail technique significantly increases the effective cross-sectional area of a satellite, subsequently increasing atmospheric drag and accelerating orbit decay. The concept proposed in this study introduced a very useful technique of orbit decay as well as deorbiting of spacecraft.
The Mars Reconnaissance Orbiter Mission: 10 Years of Exploration from Mars Orbit
Johnston, M. Daniel; Zurek, Richard W.
2016-01-01
The Mars Reconnaissance Orbiter ( MRO ) entered Mars orbit on March 10, 2006. After five months of aerobraking, a series of propulsive maneuvers were used to establish the desired low -altitude science orbit. The spacecraft has been on station in its 255 x 320 k m, sun -synchronous (approximately 3 am -pm ), primary science orbit since September 2006 performing both scientific and Mars programmatic support functions. This paper will provide a summary of the major achievements of the mission to date and the major flight activities planned for the remainder of its third Extended Mission (EM3). Some of the major flight challenges the flight team has faced are also discussed.