Amaro, J E; Simo, I Ruiz
2015-01-01
The experimental data from quasielastic electron scattering from $^{12}$C are reanalyzed in terms of a new scaling variable suggested by the interacting relativistic Fermi gas with scalar and vector interactions, which is known to generate a relativistic effective mass for the interacting nucleons. By choosing a mean value of this relativistic effective mass $m_N^* =0.8 m_N$, we observe that most of the data fall inside a region around the inverse parabola-shaped universal scaling function of the relativistic Fermi gas. This suggests a method to select the subset of data that highlight the quasielastic region, about two thirds of the total 2,500 data. Regardless of the momentum and energy transfer, this method automatically excludes the data that are not dominated by the quasielastic process. The resulting band of data reflects deviations from the perfect universality, and can be used to characterize experimentally the quasielastic peak, despite the manifest scaling violation. Moreover we show that the spread...
Relativistic electronic dressing
Attaourti, Y
2002-01-01
We study the effects of the relativistic electronic dressing in laser-assisted electron-hydrogen atom elastic collisions. We begin by considering the case when no radiation is present. This is necessary in order to check the consistency of our calculations and we then carry out the calculations using the relativistic Dirac-Volkov states. It turns out that a simple formal analogy links the analytical expressions of the differential cross section without laser and the differential cross section in presence of a laser field.
Relativistic Remnants of Non-Relativistic Electrons
Kashiwa, Taro
2015-01-01
Electrons obeying the Dirac equation are investigated under the non-relativistic $c \\mapsto \\infty$ limit. General solutions are given by derivatives of the relativistic invariant functions whose forms are different in the time- and the space-like region, yielding the delta function of $(ct)^2 - x^2$. This light-cone singularity does survive to show that the charge and the current density of electrons travel with the speed of light in spite of their massiveness.
Stanke, Monika; Palikot, Ewa; Adamowicz, Ludwik
2016-05-01
Algorithms for calculating the leading mass-velocity (MV) and Darwin (D) relativistic corrections are derived for electronic wave functions expanded in terms of n-electron explicitly correlated Gaussian functions with shifted centers and without pre-exponential angular factors. The algorithms are implemented and tested in calculations of MV and D corrections for several points on the ground-state potential energy curves of the H2 and LiH molecules. The algorithms are general and can be applied in calculations of systems with an arbitrary number of electrons.
Relativistic Runaway Electrons
Breizman, Boris
2014-10-01
This talk covers recent developments in the theory of runaway electrons in a tokamak with an emphasis on highly relativistic electrons produced via the avalanche mechanism. The rapidly growing population of runaway electrons can quickly replace a large part of the initial current carried by the bulk plasma electrons. The magnetic energy associated with this current is typically much greater than the particle kinetic energy. The current of a highly relativistic runaway beam is insensitive to the particle energy, which separates the description of the runaway current evolution from the description of the runaway energy spectrum. A strongly anisotropic distribution of fast electrons is generally prone to high-frequency kinetic instabilities that may cause beneficial enhancement of runaway energy losses. The relevant instabilities are in the frequency range of whistler waves and electron plasma waves. The instability thresholds reported in earlier work have been revised considerably to reflect strong dependence of collisional damping on the wave frequency and the role of plasma non-uniformity, including radial trapping of the excited waves in the plasma. The talk also includes a discussion of enhanced scattering of the runaways as well as the combined effect of enhanced scattering and synchrotron radiation. A noteworthy feature of the avalanche-produced runaway current is a self-sustained regime of marginal criticality: the inductive electric field has to be close to its critical value (representing avalanche threshold) at every location where the runaway current density is finite, and the current density should vanish at any point where the electric field drops below its critical value. This nonlinear Ohm's law enables complete description of the evolving current profile. Work supported by the U.S. Department of Energy Contract No. DEFG02-04ER54742 and by ITER contract ITER-CT-12-4300000273. The views and opinions expressed herein do not necessarily reflect those of
Relativistic Electron Experiment for the Undergraduate Laboratory
Marvel, Robert E
2011-01-01
We have developed an undergraduate laboratory experiment to make independent measurements of the momentum and kinetic energy of relativistic electrons from a \\beta -source. The momentum measurements are made with a magnetic spectrometer and a silicon surface-barrier detector is used to measure the kinetic energy. A plot of the kinetic energy as a function of momentum compared to the classical and relativistic predictions clearly shows the relativistic nature of the electrons. Accurate values for the rest mass of the electron and the speed of light are also extracted from the data.
Isochoric heating of reduced mass targets by ultra-intense laser produced relativistic electrons
Neumayer, P; Lee, H J; Offerman, D; Shipton, E; Kemp, A; Kritcher, A L; Doppner, T; Back, C A; Glenzer, S H
2009-02-04
We present measurements of the chlorine K-alpha emission from reduced mass targets, irradiated with ultra-high intensity laser pulses. Chlorinated plastic targets with diameters down to 50 micrometers and mass of a few 10{sup -8} g were irradiated with up to 7 J of laser energy focused to intensities of several 10{sup 19} W/cm{sup 2}. The conversion of laser energy to K-alpha radiation is measured, as well as high resolution spectra that allow observation of line shifts, indicating isochoric heating of the target up to 18 eV. A zero-dimensional 2-temperature equilibration model, combined with electron impact K-shell ionization and post processed spectra from collisional radiative calculations reproduces the observed K-alpha yields and line shifts, and shows the importance of target expansion due to the hot electron pressure.
Mass spectrum bound state systems with relativistic corrections
Dineykhan, M; Zhaugasheva, S A [Bogoliubov Laboratory of Theoretical Physics, Joint Institute for Nuclear Research, Dubna (Russian Federation); Toinbaeva, N Sh; Jakhanshir, A [al-Farabi Kazak National University, 480012 Almaty (Kazakhstan)
2009-07-28
Based on the investigation of the asymptotic behaviour of the polarization loop function for charged n scalar particles in an external gauge field, we determine the interaction Hamiltonian including relativistic corrections. The mass spectrum of the bound state is analytically derived. The mechanism for arising of the constituent mass of the relativistic bound-state forming particles is explained. The mass and the constituent mass of the two-, three- and n-body relativistic bound states are calculated taking into account relativistic corrections. The corrections arising due to the one- and two-loop electron polarization to the energy spectrum of muonic hydrogen with orbital and radial excitations are calculated.
Relativistic electron beams above thunderclouds
Füellekrug, M.; Roussel-Dupre, R.; Symbalisty, E. M. D.;
2011-01-01
Non-luminous relativistic electron beams above thunderclouds have been detected by the radio signals of low frequency similar to 40-400 kHz which they radiate. The electron beams occur similar to 2-9 ms after positive cloud-to-ground lightning discharges at heights between similar to 22-72 km above...... thunderclouds. Intense positive lightning discharges can also cause sprites which occur either above or prior to the electron beam. One electron beam was detected without any luminous sprite which suggests that electron beams may also occur independently of sprites. Numerical simulations show that beams...... of electrons partially discharge the lightning electric field above thunderclouds and thereby gain a mean energy of similar to 7MeV to transport a total charge of similar to-10mC upwards. The impulsive current similar to 3 x 10(-3) Am-2 associated with relativistic electron beams above thunderclouds...
Relativistic electron beams above thunderclouds
M. Füllekrug
2011-05-01
Full Text Available Non-luminous relativistic electron beams above thunderclouds are detected by radio remote sensing with low frequency radio signals from 40–400 kHz. The electron beams occur 2–9 ms after positive cloud-to-ground lightning discharges at heights between 22–72 km above thunderclouds. The positive lightning discharges also cause sprites which occur either above or before the electron beam. One electron beam was detected without any luminous sprite occurrence which suggests that electron beams may also occur independently. Numerical simulations show that the beamed electrons partially discharge the lightning electric field above thunderclouds and thereby gain a mean energy of 7 MeV to transport a total charge of 10 mC upwards. The impulsive current associated with relativistic electron beams above thunderclouds is directed downwards and needs to be considered as a novel element of the global atmospheric electric circuit.
Double Relativistic Electron Accelerating Mirror
Saltanat Sadykova
2013-02-01
Full Text Available In the present paper, the possibility of generation of thin dense relativistic electron layers is shown using the analytical and numerical modeling of laser pulse interaction with ultra-thin layers. It was shown that the maximum electron energy can be gained by optimal tuning between the target width, intensity and laser pulse duration. The optimal parameters were obtained from a self-consistent system of Maxwell equations and the equation of motion of electron layer. For thin relativistic electron layers, the gaining of maximum electron energies requires a second additional overdense plasma layer, thus cutting the laser radiation off the plasma screen at the instant of gaining the maximum energy (DREAM-schema.
Relativistic electron beams above thunderclouds
M. Füllekrug
2011-08-01
Full Text Available Non-luminous relativistic electron beams above thunderclouds have been detected by the radio signals of low frequency ∼40–400 kHz which they radiate. The electron beams occur ∼2–9 ms after positive cloud-to-ground lightning discharges at heights between ∼22–72 km above thunderclouds. Intense positive lightning discharges can also cause sprites which occur either above or prior to the electron beam. One electron beam was detected without any luminous sprite which suggests that electron beams may also occur independently of sprites. Numerical simulations show that beams of electrons partially discharge the lightning electric field above thunderclouds and thereby gain a mean energy of ∼7 MeV to transport a total charge of ∼−10 mC upwards. The impulsive current ∼3 × 10^{−3} Am^{−2} associated with relativistic electron beams above thunderclouds is directed downwards and needs to be considered as a novel element of the global atmospheric electric circuit.
Einstein Never Approved of Relativistic Mass
Hecht, Eugene
2009-01-01
During much of the 20th century it was widely believed that one of the significant insights of special relativity was "relativistic mass." Today there are two schools on that issue: the traditional view that embraces speed-dependent "relativistic mass," and the more modern position that rejects it, maintaining that there is only one mass and it's…
Single electron relativistic clock interferometer
Bushev, P. A.; Cole, J. H.; Sholokhov, D.; Kukharchyk, N.; Zych, M.
2016-09-01
Although time is one of the fundamental notions in physics, it does not have a unique description. In quantum theory time is a parameter ordering the succession of the probability amplitudes of a quantum system, while according to relativity theory each system experiences in general a different proper time, depending on the system's world line, due to time dilation. It is therefore of fundamental interest to test the notion of time in the regime where both quantum and relativistic effects play a role, for example, when different amplitudes of a single quantum clock experience different magnitudes of time dilation. Here we propose a realization of such an experiment with a single electron in a Penning trap. The clock can be implemented in the electronic spin precession and its time dilation then depends on the radial (cyclotron) state of the electron. We show that coherent manipulation and detection of the electron can be achieved already with present day technology. A single electron in a Penning trap is a technologically ready platform where the notion of time can be probed in a hitherto untested regime, where it requires a relativistic as well as quantum description.
Relativistic Electrons in Electric Discharges
Cinar, Deniz
discharges as the source. The “Atmosphere-Space Interactions Monitor” (ASIM) for the International Space Station in 2016, led by DTU Space, and the French microsatellite TARANIS, also with launch in 2016, will identify with certainty the source of TGFs. In preparation for the missions, the Ph.D. project has...... developed a Monte Carlo module of a simulation code to model the formation of avalanches of electrons accelerated to relativistic energies, and the generation of bremsstrahlung through interactions with the neutral atmosphere. The code will be used in the analysis of data from the two space missions. We...... scattering. However, we only explored the properties of the complete number of photons reaching space, not the distribution at speci_c locations as in the case of a satellite. With this reservation we conclude that it is not possible to deduce much information from a satellite measurement of the photons...
Energy spectra in relativistic electron precipitation events.
Rosenberg, T. J.; Lanzerotti, L. J.; Bailey, D. K.; Pierson, J. D.
1972-01-01
Two events in August 1967, categorized as relativistic electron precipitation (REP) events by their effect on VHF transmissions propagated via the forward-scatter mode, have been examined with regard to the energy spectra of trapped and precipitated electrons. These two substorm-associated events August 11 and August 25 differ with respect to the relativistic, trapped electron population at synchronous altitude; in the August 25 event there was a nonadiabatic enhancement of relativistic (greater than 400 keV) electrons, while in the August 11 event no relativistic electrons were produced. In both events electron spectra deduced from bremsstrahlung measurements (made on a field line close to that of the satellite) had approximately the same e-folding energies as the trapped electron enhancements. However, the spectrum of electrons in the August 25 event was significantly harder than the spectrum in the event of August 11.
Relativistic Langevin equation for runaway electrons
Mier, J. A.; Martin-Solis, J. R.; Sanchez, R.
2016-10-01
The Langevin approach to the kinetics of a collisional plasma is developed for relativistic electrons such as runaway electrons in tokamak plasmas. In this work, we consider Coulomb collisions between very fast, relativistic electrons and a relatively cool, thermal background plasma. The model is developed using the stochastic equivalence of the Fokker-Planck and Langevin equations. The resulting Langevin model equation for relativistic electrons is an stochastic differential equation, amenable to numerical simulations by means of Monte-Carlo type codes. Results of the simulations will be presented and compared with the non-relativistic Langevin equation for RE electrons used in the past. Supported by MINECO (Spain), Projects ENE2012-31753, ENE2015-66444-R.
Bodek, K.; Rozpędzik, D.; Zejma, J. [Jagiellonian University, Faculty of Physics, Astronomy and Applied Informatics, Reymonta 4, 30059 Kraków (Poland); Caban, P.; Rembieliński, J.; Włodarczyk, M. [University of Łódź, Faculty of Physics and Applied Informatics, Pomorska 149/153, 90236 Łódź (Poland); Ciborowski, J. [University of Warsaw, Faculty of Physics, Hoza 69, 00681 Warsaw (Poland); Enders, J.; Köhler, A. [Technische Universität Darmstadt, Institut für Kernphysik, Schlossgartenstraße 9, 64289 Darmstadt (Germany); Kozela, A. [Institute of Nuclear Physics, Polish Academy of Sciences, Radzikowskiego 152, 31342 Kraków (Poland)
2013-11-07
The Polish-German project QUEST aims at studying relativistic quantum spin correlations of the Einstein-Rosen-Podolsky-Bohm type, through measurement of the correlation function and the corresponding probabilities for relativistic electron pairs. The results will be compared to theoretical predictions obtained by us within the framework of relativistic quantum mechanics, based on assumptions regarding the form of the relativistic spin operator. Agreement or divergence will be interpreted in the context of non-uniqueness of the relativistic spin operator in quantum mechanics as well as dependence of the correlation function on the choice of observables representing the spin. Pairs of correlated electrons will originate from the Mo/ller scattering of polarized 15 MeV electrons provided by the superconducting Darmstadt electron linear accelerator S-DALINAC, TU Darmstadt, incident on a Be target. Spin projections will be determined using the Mott polarimetry technique. Measurements (starting 2013) are planned for longitudinal and transverse beam polarizations and different orientations of the beam polarization vector w.r.t. the Mo/ller scattering plane. This is the first project to study relativistic spin correlations for particles with mass.
Artru, X. [Inst. de Physique Nucleaire, Lyon-1 Univ., 69 - Villeurbanne (France); Collaboration: IPN-Lyon, IRMM (Gell), LURE (Orsay); Collaboration: IPN-Lyon, LAL and IEF (Orsay), HIP (Helsinki), INFN (Frascati, Milan)
1998-12-31
We have studied different effects related to electromagnetic interaction of relativistic electrons in matter and investigated their use in beam profile measurements. (authors) 4 refs. Short communication
Glueball Masses in Relativistic Potential Model
Shpenik, A; Kis, J; Fekete, Yu
2000-01-01
The problem of glueball mass spectra using the relativistic Dirac equation is studied. Also the Breit-Fermi approach used to obtaining hyperfine splitting in glueballs. Our approach is based on the assumption, that the nature and the forces between two gluons are the short-range. We were to calculate the glueball masses with used screened potential.
Gravitational mass of relativistic matter and antimatter
Tigran Kalaydzhyan
2015-12-01
Full Text Available The universality of free fall, the weak equivalence principle (WEP, is a cornerstone of the general theory of relativity, the most precise theory of gravity confirmed in all experiments up to date. The WEP states the equivalence of the inertial, m, and gravitational, mg, masses and was tested in numerous occasions with normal matter at relatively low energies. However, there is no confirmation for the matter and antimatter at high energies. For the antimatter the situation is even less clear – current direct observations of trapped antihydrogen suggest the limits −65
Gravitational mass of relativistic matter and antimatter
Kalaydzhyan, Tigran
2015-01-01
The universality of free fall, the so-called weak equivalence principle (WEP), is a cornerstone of the general theory of relativity, the most precise theory of gravity confirmed in all experiments up to date. The WEP states the equivalence of the inertial and gravitational masses and was tested in numerous occasions with normal matter at relatively low energies. However, there is no proof for the matter and antimatter at high energies. %coming from ground-based experiments. For the antimatter the situation is even less clear -- current direct observations of trapped antihydrogen suggest the limits -65 < m_g / m < 110 not ruling out antigravity, i.e. repulsion of the antimatter by Earth. Here we demonstrate a bound 1 - 4x10^{-7} < m_g/m < 1 + 2x10^{-7} on the gravitational mass of relativistic electrons and positrons in the potential of the Local Supercluster (LS) coming from the Large Electron-Positron Collider (LEP) and Tevatron accelerator experiments. By considering annual variations of the sol...
Single-electron detection and spectroscopy via relativistic cyclotron radiation
Asner, David M.; Bradley, Rich; De Viveiros Souza Filho, Luiz A.; Doe, Peter J.; Fernandes, Justin L.; Fertl, M.; Finn, Erin C.; Formaggio, Joseph; Furse, Daniel L.; Jones, Anthony M.; Kofron, Jared N.; LaRoque, Benjamin; Leber, Michelle; MCBride, Lisa; Miller, M. L.; Mohanmurthy, Prajwal T.; Monreal, Ben; Oblath, Noah S.; Robertson, R. G. H.; Rosenberg, Leslie; Rybka, Gray; Rysewyk, Devyn M.; Sternberg, Michael G.; Tedeschi, Jonathan R.; Thummler, Thomas; VanDevender, Brent A.; Woods, N. L.
2015-04-01
It has been understood since 1897 that accelerating charges should emit electromagnetic radiation. Cyclotron radiation, the particular form of radiation emitted by an electron orbiting in a magnetic field, was first derived in 1904. Despite the simplicity of this concept, and the enormous utility of electron spectroscopy in nuclear and particle physics, single-electron cyclotron radiation has never been observed directly. Here we demonstrate single-electron detection in a novel radiofrequency spectrometer. We observe the cyclotron radiation emitted by individual electrons that are produced with mildly-relativistic energies by a gaseous radioactive source and are magnetically trapped. The relativistic shift in the cyclotron frequency permits a precise electron energy measurement. Precise beta electron spectroscopy from gaseous radiation sources is a key technique in modern efforts to measure the neutrino mass via the tritium decay endpoint, and this work is a proof-of-concept for future neutrino mass experiments using this technique.
Single electron detection and spectroscopy via relativistic cyclotron radiation
Asner, D M; de Viveiros, L; Doe, P J; Fernandes, J L; Fertl, M; Finn, E C; Formaggio, J A; Furse, D; Jones, A M; Kofron, J N; LaRoque, B H; Leber, M; McBride, E L; Miller, M L; Mohanmurthy, P; Monreal, B; Oblath, N S; Robertson, R G H; Rosenberg, L J; Rybka, G; Rysewyk, D; Sternberg, M G; Tedeschi, J R; Thummler, T; VanDevender, B A; Woods, N L
2014-01-01
It has been understood since 1897 that accelerating charges must emit electromagnetic radiation. Cyclotron radiation, the particular form of radiation emitted by an electron orbiting in a magnetic field, was first derived in 1904. Despite the simplicity of this concept, and the enormous utility of electron spectroscopy in nuclear and particle physics, single-electron cyclotron radiation has never been observed directly. Here we demonstrate single-electron detection in a novel radiofrequency spec- trometer. We observe the cyclotron radiation emitted by individual magnetically-trapped electrons that are produced with mildly-relativistic energies by a gaseous radioactive source. The relativistic shift in the cyclotron frequency permits a precise electron energy measurement. Precise beta elec- tron spectroscopy from gaseous radiation sources is a key technique in modern efforts to measure the neutrino mass via the tritium decay endpoint, and this work demonstrates a fundamentally new approach to precision beta sp...
Relativistic elastic differential cross sections for equal mass nuclei
C.M. Werneth
2015-10-01
Full Text Available The effects of relativistic kinematics are studied for nuclear collisions of equal mass nuclei. It is found that the relativistic and non-relativistic elastic scattering amplitudes are nearly indistinguishable, and, hence, the relativistic and non-relativistic differential cross sections become indistinguishable. These results are explained by analyzing the Lippmann–Schwinger equation with the first order optical potential that was employed in the calculation.
Relativistic elastic differential cross sections for equal mass nuclei
Werneth, C.M., E-mail: charles.m.werneth@nasa.gov [NASA Langley Research Center, 2 West Reid Street, Hampton, VA 23681 (United States); Maung, K.M.; Ford, W.P. [The University of Southern Mississippi, 118 College Drive, Box 5046, Hattiesburg, MS 39406 (United States)
2015-10-07
The effects of relativistic kinematics are studied for nuclear collisions of equal mass nuclei. It is found that the relativistic and non-relativistic elastic scattering amplitudes are nearly indistinguishable, and, hence, the relativistic and non-relativistic differential cross sections become indistinguishable. These results are explained by analyzing the Lippmann–Schwinger equation with the first order optical potential that was employed in the calculation.
a Relativistic Calculation of Baryon Masses
Giammarco, Joseph Michael
1990-01-01
We calculate ground state baryon masses using a saddle-point variational (SPV) method, which permits us the use of fully relativistic 4-component Dirac spinors without the need for positive energy projection operators. This variational approach has been shown to work in the relativistic domain for one particle in an external potential (Dirac equation). We have extended its use to the relativistic 3-body Breit equation. Our procedure is as follows: we pick a trial wave function having the appropriate spin, flavor and color dependence. This can be accomplished with a non-symmetric relativistic spatial wave function having two different size parameters if the the first two quarks are always chosen to be identical. We than calculate an energy eigenvalue for the particle state and vary the parameters in our wave function to search for a "saddle-point". We minimize the energy with respect to the two size parameters and maximize with respect to two parameters that measure the contribution from the negative-energy states. This gives the baryon's mass as a function of four input parameters: the masses of the up, down and strange quarks (m_{u=d },m_{s}), and the strength of the coupling constants for the potentials ( alpha_{s},mu). We do this for the eight Baryon ground states and fit these to experimental data. This fit gives the values of the input parameters. For the potentials we use a coulombic term to represent one-gluon exchange and a linear term for confinement. For both terms we include a retardation term required by relativity. We also add delta function and spin-spin terms to account for the large contribution of the coulomb interaction at the origin. The results we obtain from our SPV method are in good agreement with experimental data. The actual search for the saddle-point parameters and the fitting of the quark masses and the values of the coupling strengths was done on a CDC Cyber 860.
Investigation of relativistic runaway electrons
Jaspers, R.; Lopes Cardozo, N.J.; Schueller, F.C. [FOM-Instituut voor Plasmafysica, Rijnhuizen (Netherlands); Finken, K.H.; Mank, G.; Hoenen, F. [Forschungszentrum Juelich GmbH (Germany). Inst. fuer Plasmaphysik; Boedo, J. [California Univ., Los Angeles, CA (United States). Inst. of Plasma and Fusion Research
1993-12-31
The runaway generation during disruptions is regarded as a serious problem in future tokamak devices. The number and the high energy of these runaways can lead to considerable damage of wall components. In the TEXTOR tokamak (R{sub 0}=1.75 m, a=0.46 m; I{sub p}=350 kA, B{sub t}=2.25T, flat top time {approx_equal}2 s), low density discharges (n{sub e} < 1x10{sup 19} m{sup -3}) are analyzed to study the creation mechanism and the energy increase of the runaways. This is mainly done by the synchrotron radiation emitted by highly relativistic runaways (> 20 MeV). The general features of this synchrotron radiation will be described in Sect.2. In Sect.3 the creation rate of runaways is derived from this radiation. An intriguing observation made at the end of low density ohmic discharges is a fast increase in the pitch angle (i.e. the ratio of perpendicular to parallel velocity) from the runaways on a time scale of less than 65 {mu}s. This phenomenon is discussed in Sect.4. Finally some conclusions will be drawn on the implications these results have for future tokamak operation. (author) 4 refs., 3 figs.
Particle Acceleration in Relativistic Magnetized Collisionless Electron-Ion Shocks
Sironi, Lorenzo
2010-01-01
We investigate shock structure and particle acceleration in relativistic magnetized collisionless electron-ion shocks by means of 2.5D particle-in-cell simulations with ion-to-electron mass ratios (m_i/m_e) ranging from 16 to 1000. We explore a range of inclination angles between the pre-shock magnetic field and the shock normal. In "subluminal" shocks, where relativistic particles can escape ahead of the shock along the magnetic field lines, ions are efficiently accelerated via a Fermi-like mechanism. The downstream ion spectrum consists of a relativistic Maxwellian and a high-energy power-law tail, which contains ~5% of ions and ~30% of ion energy. Its slope is -2.1. Upstream electrons enter the shock with lower energy than ions, so they are more strongly tied to the field. As a result, only ~1% of the incoming electrons are Fermi-accelerated at the shock before being advected downstream, where they populate a steep power-law tail (with slope -3.5). For "superluminal" shocks, where relativistic particles ca...
Relativistic internally contracted multireference electron correlation methods
Shiozaki, Toru
2015-01-01
We report internally contracted relativistic multireference configuration interaction (ic-MRCI), complete active space second-order perturbation (CASPT2), and strongly contracted n-electron valence state perturbation theory (NEVPT2) on the basis of the four-component Dirac Hamiltonian, enabling accurate simulations of relativistic, quasi-degenerate electronic structure of molecules containing transition-metal and heavy elements. Our derivation and implementation of ic-MRCI and CASPT2 are based on an automatic code generator that translates second-quantized ans\\"atze to tensor-based equations, and to efficient computer code. NEVPT2 is derived and implemented manually. The rovibrational transition energies and absorption spectra of HI and TlH are presented to demonstrate the accuracy of these methods.
Relativistic electromagnetic waves in an electron-ion plasma
Chian, Abraham C.-L.; Kennel, Charles F.
1987-01-01
High power laser beams can drive plasma particles to relativistic energies. An accurate description of strong waves requires the inclusion of ion dynamics in the analysis. The equations governing the propagation of relativistic electromagnetic waves in a cold electron-ion plasma can be reduced to two equations expressing conservation of energy-momentum of the system. The two conservation constants are functions of the plasma stream velocity, the wave velocity, the wave amplitude, and the electron-ion mass ratio. The dynamic parameter, expressing electron-ion momentum conversation in the laboratory frame, can be regarded as an adjustable quantity, a suitable choice of which will yield self-consistent solutions when other plasma parameters were specified. Circularly polarized electromagnetic waves and electrostatic plasma waves are used as illustrations.
Noether's theorem of a rotational relativistic variable mass system
方建会; 赵嵩卿
2002-01-01
Noether's theory of a rotational relativistic variable mass system is studied. Firstly, Jourdain's principle of therotational relativistic variable mass system is given. Secondly, on the basis of the invariance of the Jourdain's principleunder the infinitesimal transformations of groups, Noether's theorem and its inverse theorem of the rotational relativisticvariable mass system are presented. Finally, an example is given to illustrate the application of the result.
Helical relativistic electron beam and THz radiation
Son, S
2011-01-01
A THz laser generation utilizing a helical relativistic electron beam propagating through a strong magnetic field is discussed. The initial amplification rate in this scheme is much stronger than that in the conventional free electron laser. A magnetic field of the order of Tesla can yield a radiation in the range of 0.5 to 3 THz, corresponding to the total energy of mJ and the duration of tens of pico-second, or the temporal power of the order of GW.
Relativistic electrons produced by foreshock disturbances
Wilson, L B; Turner, D L; Osmane, A; Caprioli, D; Angelopoulos, V
2016-01-01
Foreshock disturbances -- large-scale (~1000 km to >30,000 km), transient (~5-10 per day - lasting ~10s of seconds to several minutes) structures [1,2] - generated by suprathermal (>100 eV to 100s of keV) ions [3,4] arise upstream of Earth's bow shock formed by the solar wind colliding with the Earth's magnetosphere. They have recently been found to accelerate ions to energies of several keV [5,6]. Although electrons in Saturn's high Mach number (M > 40) bow shock can be accelerated to relativistic energies (nearly 1000 keV) [7], it has hitherto been thought impossible to accelerate electrons at the much weaker (M < 20) Earth's bow shock beyond a few 10s of keV [8]. Here we report observations of electrons energized by foreshock disturbances to energies up to at least ~300 keV. Although such energetic electrons have been previously reported, their presence has been attributed to escaping magnetospheric particles [9,10] or solar events [11]. These relativistic electrons are not associated with any solar act...
Relativistic mean-field mass models
Peña-Arteaga, D.; Goriely, S.; Chamel, N.
2016-10-01
We present a new effort to develop viable mass models within the relativistic mean-field approach with density-dependent meson couplings, separable pairing and microscopic estimations for the translational and rotational correction energies. Two interactions, DD-MEB1 and DD-MEB2, are fitted to essentially all experimental masses, and also to charge radii and infinite nuclear matter properties as determined by microscopic models using realistic interactions. While DD-MEB1 includes the σ, ω and ρ meson fields, DD-MEB2 also considers the δ meson. Both mass models describe the 2353 experimental masses with a root mean square deviation of about 1.1 MeV and the 882 measured charge radii with a root mean square deviation of 0.029 fm. In addition, we show that the Pb isotopic shifts and moments of inertia are rather well reproduced, and the equation of state in pure neutron matter as well as symmetric nuclear matter are in relatively good agreement with existing realistic calculations. Both models predict a maximum neutron-star mass of more than 2.6 solar masses, and thus are able to accommodate the heaviest neutron stars observed so far. However, the new Lagrangians, like all previously determined RMF models, present the drawback of being characterized by a low effective mass, which leads to strong shell effects due to the strong coupling between the spin-orbit splitting and the effective mass. Complete mass tables have been generated and a comparison with other mass models is presented.
Relativistic mean-field mass models
Pena-Arteaga, D.; Goriely, S.; Chamel, N. [Universite Libre de Bruxelles, Institut d' Astronomie et d' Astrophysique, CP-226, Brussels (Belgium)
2016-10-15
We present a new effort to develop viable mass models within the relativistic mean-field approach with density-dependent meson couplings, separable pairing and microscopic estimations for the translational and rotational correction energies. Two interactions, DD-MEB1 and DD-MEB2, are fitted to essentially all experimental masses, and also to charge radii and infinite nuclear matter properties as determined by microscopic models using realistic interactions. While DD-MEB1 includes the σ, ω and ρ meson fields, DD-MEB2 also considers the δ meson. Both mass models describe the 2353 experimental masses with a root mean square deviation of about 1.1 MeV and the 882 measured charge radii with a root mean square deviation of 0.029 fm. In addition, we show that the Pb isotopic shifts and moments of inertia are rather well reproduced, and the equation of state in pure neutron matter as well as symmetric nuclear matter are in relatively good agreement with existing realistic calculations. Both models predict a maximum neutron-star mass of more than 2.6 solar masses, and thus are able to accommodate the heaviest neutron stars observed so far. However, the new Lagrangians, like all previously determined RMF models, present the drawback of being characterized by a low effective mass, which leads to strong shell effects due to the strong coupling between the spin-orbit splitting and the effective mass. Complete mass tables have been generated and a comparison with other mass models is presented. (orig.)
On the relativistic mass function and averaging in cosmology
Ostrowski, Jan J; Roukema, Boudewijn F
2016-01-01
The general relativistic description of cosmological structure formation is an important challenge from both the theoretical and the numerical point of views. In this paper we present a brief prescription for a general relativistic treatment of structure formation and a resulting mass function on galaxy cluster scales in a highly generic scenario. To obtain this we use an exact scalar averaging scheme together with the relativistic generalization of Zel'dovich's approximation (RZA) that serves as a closure condition for the averaged equations.
Torsion effects on a relativistic position-dependent mass system
Vitória, R L L
2016-01-01
We analyse a relativistic scalar particle with a position-dependent mass in a spacetime with a space-like dislocation by showing that relativistic bound states solutions can be achieved. Further, we consider the presence of the Coulomb potential and analyse the relativistic position-dependent mass system subject to the Coulomb potential in the spacetime with a space-like dislocation. We also show that a new set of relativistic bound states solutions can be obtained, where there also exists the influence of torsion of the relativistic energy levels. Finally, we investigate an analogue of the Aharonov-Bohm effect for bound states in this position-dependent mass in a spacetime with a space-like dislocation.
Relativistic electrons from sparks in the laboratory
Østgaard, N.; Carlson, B. E.; Nisi, R. S.; Gjesteland, T.; Grøndahl, Ø.; Skeltved, A.; Lehtinen, N. G.; Mezentsev, A.; Marisaldi, M.; Kochkin, P.
2016-03-01
Discharge experiments were carried out at the Eindhoven University of Technology in 2013. The experimental setup was designed to search for electrons produced in meter-scale sparks using a 1 MV Marx generator. Negative voltage was applied to the high voltage (HV) electrode. Five thin (1 mm) plastic detectors (5 cm2 each) were distributed in various configurations close to the spark gap. Earlier studies have shown (for HV negative) that X-rays are produced when a cloud of streamers is developed 30-60 cm from the negative electrode. This indicates that the electrons producing the X-rays are also accelerated at this location, that could be in the strong electric field from counterstreamers of opposite polarity. Comparing our measurements with modeling results, we find that ˜300 keV electrons produced about 30-60 cm from the negative electrode are the most likely source of our measurements. A statistical analysis of expected detection of photon bursts by these fiber detectors indicates that only 20%-45% of the detected bursts could be from soft (˜10 keV) photons, which further supports that the majority of detected bursts are produced by relativistic electrons.
Relativistic description of electron scattering on the deuteron
Hummel, E
1994-01-01
Within a quasipotential framework a relativistic analysis is presented of the deuteron current. Assuming that the singularities from the nucleon propagators are important, a so-called equal time approximation of the current is constructed. This is applied to both elastic and inelastic electron scattering. As dynamical model the relativistic one boson exchange model is used. Reasonable agreement is found with a previous relativistic calculation of the elastic electromagnetic form factors of the deuteron. For the unpolarized inelastic electron scattering effects of final state interactions and relativistic corrections to the structure functions are considered in the impulse approximation. Two specific kinematic situations are studied as examples.
Particle Acceleration in Relativistic Electron-Ion Outlfows
Lloyd-Ronning, Nicole M
2016-01-01
We use the Los Alamos VPIC code to investigate particle acceleration in relativistic, unmagnetized, collisionless electron-ion plasmas. We run our simulations both with a realistic proton-to-electron mass ratio m_p/m_e = 1836, as well as commonly employed mass ratios of m_p/m_e =100 and 25, and show that results differ among the different cases. In particular, for the physically accurate mass ratio, electron acceleration occurs efficiently in a narrow region of a few hundred inertial lengths near the flow front, producing a power law dN/dgamma ~ gamma^(-p) with p ~ -2 developing over a few decades in energy, while acceleration is weak in the region far downstream. We find 20%, 10%, and 0.2% of the total energy given to the electrons for mass ratios of 25, 100, and 1836 respectively at a time of 2500 (w_p)^-1. Our simulations also show significant magnetic field generation just ahead of and behind the the flow front, with about 1% of the total energy going into the magnetic field for a mass ratio of 25 and 100...
Millan, R. M.; Lin, R. P.; Smith, D. M.; McCarthy, M. P.
2007-05-01
We present the first quantitative comparison of precipitating and geomagnetically trapped electron flux during a relativistic electron depletion event. Intense bremsstrahlung X-ray emission from relativistic electron precipitation was observed on January 19-20, 2000 (21:20-00:45 UT) by the germanium spectrometer on the MAXIS balloon payload (-7.2 to -9.3 E, 74 S corresponding to IGRF L = 4.7, 1920-2240 MLT). A rapid decrease in the geosynchronous >2 MeV electron flux was simultaneously observed at GOES-8 and GOES-10, and between 0.34-3.6 MeV by GPS ns33 at L = 4.7. The observations show that electrons were lost to the atmosphere early in the flux depletion event, during a period of magnetic field stretching in the tail. The observed X-ray spectrum is well modeled by an exponential distribution of precipitating electrons with an e-folding energy of 290 keV and a lower-energy cut-off of 400 keV. The duration of the event implies precipitation extended over at least 3 hours of MLT, assuming a source fixed in local time. Comparison of the precipitation rate with the flux decrease measured at GPS implies that the loss cone flux was only ~1% of the equatorial flux. However, precipitation is sufficient to account for the rate of flux decrease if it extended over 2-3 hours of local time.
Hussain, S.; Mahmood, S.; Rehman, Aman-ur- [Theoretical Physics Division (TPD), PINSTECH, P.O. Nilore, Islamabad 44000, Pakistan and Pakistan Institute of Engineering and Applied Sciences (PIEAS), P.O. Nilore, Islamabad 44000 (Pakistan)
2014-11-15
Linear and nonlinear propagation of magnetosonic waves in the perpendicular direction to the ambient magnetic field is studied in dense plasmas for non-relativistic and ultra-relativistic degenerate electrons pressure. The sources of nonlinearities are the divergence of the ions and electrons fluxes, Lorentz forces on ions and electrons fluids and the plasma current density in the system. The Korteweg-de Vries equation for magnetosonic waves propagating in the perpendicular direction of the magnetic field is derived by employing reductive perturbation method for non-relativistic as well as ultra-relativistic degenerate electrons pressure cases in dense plasmas. The plots of the magnetosonic wave solitons are also shown using numerical values of the plasma parameters such a plasma density and magnetic field intensity of the white dwarfs from literature. The dependence of plasma density and magnetic field intensity on the magnetosonic wave propagation is also pointed out in dense plasmas for both non-relativistic and ultra-relativistic degenerate electrons pressure cases.
Quantum resonances in reflection of relativistic electrons and positrons
Eykhorn, Yu.L.; Korotchenko, K.B. [National Research Tomsk Polytechnic University, 30, Lenin Avenue, Tomsk 634050 (Russian Federation); Pivovarov, Yu.L. [National Research Tomsk Polytechnic University, 30, Lenin Avenue, Tomsk 634050 (Russian Federation); Tomsk State University, 36, Lenin Avenue, Tomsk 634050 (Russian Federation); Takabayashi, Y. [SAGA Light Source, 8-7 Yayoigaoka, Tosu, Saga 841-0005 (Japan)
2015-07-15
Calculations based on the use of realistic potential of the system of crystallographic planes confirm earlier results on existence of resonances in reflection of relativistic electrons and positrons by the crystal surface, if the crystallographic planes are parallel to the surface.The physical reason of predicted phenomena, similar to the band structure of transverse energy levels, is connected with the Bloch form of the wave functions of electrons (positrons) near the crystallographic planes, which appears both in the case of planar channeling of relativistic electrons (positrons) and in reflection by a crystal surface. Calculations show that positions of maxima in reflection of relativistic electrons and positrons by crystal surface specifically depend on the angle of incidence with respect to the crystal surface and relativistic factor of electrons/positrons. These maxima form the Darwin tables similar to that in ultra-cold neutron diffraction.
RELATIVISTIC ELECTRON LOSSES RELATED TO PROTON PRECIPITATION AND EMIC WAVES
Soraas, F.; Sandanger, M. I.; Aarsnes, K.; Oksavik, K.; Evans, D. S.
2009-12-01
Observations of loss of relativistic electrons to the atmosphere is presented and related to SW parameters. It is shown that the L-region of relativistic electron loss matched the anisotropic proton zone. In this zone the pitch angle distribution of the protons are unstable and can generate/amplify EMIC waves which in turn scatter the electrons into the atmosphere. In spatial limited regions, located close to the plasma pause, there can be enhanced losses of protons (sometime completely filling the loss cone). These regions of proton losses (spikes) are shown to give rise to EMIC waves leading to enhance scattering of the relativistic electrons. In the main phase of the storm the proton spikes are located in the midnight/evening sector, but in the storm recovery phase they are located at all MLTs. The anisotropic proton zone and proton spikes are observed in all storms, but not all storms contain an elevated flux of relativistic electrons.
Dependence of geosynchronous relativistic electron enhancements on geomagnetic parameters
Dmitriev, A V
2014-01-01
Relativistic electron fluxes observed in geosynchronous orbit by GOES-8 in 1997 to 2000 were considered as a complex function of geomagnetic indices PC, Kp, and Dst as well as parameters of the magnetosphere size, subsolar Rs and terminator Rf magnetopause distances. A geosynchronous relativistic electron enhancement (GREE) is determined as daily maximal electron flux exceeding the upper root mean square deviation (RMSD) threshold of about 1500 (cm2s sr)-1. Comparison analysis of the GREE dynamics and geomagnetic conditions on the rising phase of current solar cycle revealed suppression of the relativistic electron enhancements by substantially increased strong geomagnetic activity in the solar maximum. Statistical consideration of a relationship between the GREEs and the geomagnetic parameters showed that the most important parameters controlling the geosynchronous relativistic electron enhancements were 4-day averaged Kp index, PC index and magnetopause termination distance Rf delayed respectively on 3 and ...
Relativistic effects in elastic scattering of electrons in TEM.
Rother, Axel; Scheerschmidt, Kurt
2009-01-01
Transmission electron microscopy typically works with highly accelerated thus relativistic electrons. Consequently the scattering process is described within a relativistic formalism. In the following, we will examine three different relativistic formalisms for elastic electron scattering: Dirac, Klein-Gordon and approximated Klein-Gordon, the standard approach. This corresponds to a different consideration of spin effects and a different coupling to electromagnetic potentials. A detailed comparison is conducted by means of explicit numerical calculations. For this purpose two different formalisms have been applied to the approaches above: a numerical integration with predefined boundary conditions and the multislice algorithm, a standard procedure for such simulations. The results show a negligibly small difference between the different relativistic equations in the vicinity of electromagnetic potentials, prevailing in the electron microscope. The differences between the two numeric approaches are found to be small for small-angle scattering but eventually grow large for large-angle scattering, recorded for instance in high-angle annular dark field.
A search for relativistic electron induced stratospheric ozone depletion
Aikin, Arthur C.
1994-01-01
Possible ozone changes at 1 mb associated with the time variation and precipitation of relativistic electrons are investigated by examining the NIMBUS 7 SBUV ozone data set and corresponding temperatures derived from NMC data. No ozone depletion was observed in high-latitude summer when temperature fluctuations are small. In winter more variation in ozone occurs, but large temperature changes make it difficult to identify specific ozone decreases as being the result of relativistic electron precipitation.
Resonant enhancement of relativistic electron fluxes during geomagnetically active periods
I. Roth
Full Text Available The strong increase in the flux of relativistic electrons during the recovery phase of magnetic storms and during other active periods is investigated with the help of Hamiltonian formalism and simulations of test electrons which interact with whistler waves. The intensity of the whistler waves is enhanced significantly due to injection of 10-100 keV electrons during the substorm. Electrons which drift in the gradient and curvature of the magnetic field generate the rising tones of VLF whistler chorus. The seed population of relativistic electrons which bounce along the inhomogeneous magnetic field, interacts resonantly with the whistler waves. Whistler wave propagating obliquely to the magnetic field can interact with energetic electrons through Landau, cyclotron, and higher harmonic resonant interactions when the Doppler-shifted wave frequency equals any (positive or negative integer multiple of the local relativistic gyrofrequency. Because the gyroradius of a relativistic electron may be the order of or greater than the perpendicular wavelength, numerous cyclotron, harmonics can contribute to the resonant interaction which breaks down the adiabatic invariant. A similar process diffuses the pitch angle leading to electron precipitation. The irreversible changes in the adiabatic invariant depend on the relative phase between the wave and the electron, and successive resonant interactions result in electrons undergoing a random walk in energy and pitch angle. This resonant process may contribute to the 10-100 fold increase of the relativistic electron flux in the outer radiation belt, and constitute an interesting relation between substorm-generated waves and enhancements in fluxes of relativistic electrons during geomagnetic storms and other active periods.
Key words. Magnetospheric physics (energetic particles · trapped; plasma waves and instabilities; storms and substorms
Multidimensional electron beam-plasma instabilities in the relativistic regime
BRET, ANTOINE; Gremillet, Laurent; Dieckmann, Mark Eric
2010-01-01
The interest in relativistic beam-plasma instabilities has been greatly rejuvenated over the past two decades by novel concepts in laboratory and space plasmas. Recent advances in this long-standing field are here reviewed from both theoretical and numerical points of view. The primary focus is on the two-dimensional spectrum of unstable electromagnetic waves growing within relativistic, unmagnetized, and uniform electron beam-plasma systems. Although the goal is to provide a unified picture ...
Shock Versus Solar Flare Production of Heliospheric Relativistic Electron Events
Kahler, S. W.; Cliver, E. W.
2006-12-01
Electrons with relativistic (E > 0.3 MeV) energies are often observed as discrete events in the inner heliosphere. Their sharp onsets and antisunward flows indicate that they are produced in solar transient events. In general their origins can be associated in time with both solar flares and coronal mass ejections (CMEs). Unlike the solar energetic proton (SEP) and ion events, we do not have the advantage of particle elemental abundances and charge states as source diagnostics. We review the characteristics of the electron events observed on the Helios, Venera, ISEE-3, Phobos, and other inner heliospheric spacecraft to determine whether they are more likely to be produced by broad coronal shocks driven by CMEs or by solar flare processes associated with magnetic reconnection. Electron intensity-time profiles and energy spectra are compared with properties of flares and CMEs for this determination. Recent comparisons of peak electron and SEP event intensities provide strong evidence for the shock interpretation, but definitive results require the observations provided by the Sentinels mission.
Investigation of Relativistic Electron Resonance with EMIC Waves
Woodger, L. A.; Millan, R. M.; Denton, R. E.
2008-12-01
Wave-particle interaction of relativistic electrons with EMIC waves has been proposed as an important loss mechanism for radiation belt electrons (e.g. Thorne and Andreoli, 1980). Lorentzen et al (2000) and Millan et al (2002) suggested this mechanism to be responsible for dusk side relativistic electron precipitation (REP) detected by balloon borne instrumentation. This study will use the linear electromagnetic dispersion code WHAMP to investigate the effects of density, magnetic field, anisotropy, and heavy ions on the minimum resonance energy for relativistic electrons with EMIC waves. Results will be compared with observations of REP during the MAXIS balloon campaign on Jan. 19, 2000 and the MINIS balloon campaign on Jan. 21, 2005.
Investigating Plasmasphere Location during Relativistic Electron Precipitation Events
Woodger, L. A.; Millan, R. M.; Goldstein, J.; McCarthy, M. P.; Smith, D. M.; Sample, J. G.
2006-12-01
The plasmasphere plays a crucial role in the generation of different wave modes and their resonance conditions with radiation belt relativistic electrons. Meredith's (et. al., 2003) statistical study of resonant conditions for >2MeV electrons with EMIC waves found that the majority of these events occur in the vicinity of the plasmpause. The MAXIS and MINIS balloon observations found a distinct class of relativistic electron precipitation occurring at dusk, suggesting EMIC waves as a possible precipitation mechanism. We investigate the location of these relativistic electron precipitation events with respect to the plasmapause using data from IMAGE EUV, POLAR EFI, and a plasmapause test particle simulation driven by an electric field model with terms representing solar-wind-driven convection and ring-current-ionospheric coupling.
Investigating EMIC Waves as a Precipitation Mechanism for Relativistic Electrons
Li, Z.; Millan, R. M.; Woodger, L. A.
2012-12-01
Evidence has indicated that EMIC waves may be one of the major causes of relativistic electron precipitation (REP). We solved the pitch-angle diffusion equation for the scattering of relativistic electrons by EMIC waves, and generated flux-energy spectra of the precipitating electrons. After being converted into Bremsstrahlung X-ray counts, these spectra can be directly compared with previous (e.g. MAXIS, MINIS, BARREL test campaigns) and future (e.g. BARREL) balloon spectra measurements to determine if EMIC waves are the causes of the REP events. Parameter studies have also been conducted to investigate the influence of various geomagnetic parameters and environmental conditions on the REP spectra.
Mass, Momentum and Kinetic Energy of a Relativistic Particle
Zanchini, Enzo
2010-01-01
A rigorous definition of mass in special relativity, proposed in a recent paper, is recalled and employed to obtain simple and rigorous deductions of the expressions of momentum and kinetic energy for a relativistic particle. The whole logical framework appears as the natural extension of the classical one. Only the first, second and third laws of…
Solitary waves in dusty plasmas with weak relativistic effects in electrons and ions
Kalita, B. C., E-mail: bckalita123@gmail.com [Gauhati University, Department of Mathematics (India); Choudhury, M., E-mail: choudhurymamani@gmail.com [Handique Girls’ College, Department of Mathematics (India)
2016-10-15
Two distinct classes of dust ion acoustic (DIA) solitary waves based on relativistic ions and electrons, dust charge Z{sub d} and ion-to-dust mass ratio Q’ = m{sub i}/m{sub d} are established in this model of multicomponent plasmas. At the increase of mass ratio Q’ due to increase of relativistic ion mass and accumulation of more negative dust charges into the plasma causing decrease of dust mass, relativistic DIA solitons of negative potentials are abundantly observed. Of course, relativistic compressive DIA solitons are also found to exist simultaneously. Further, the decrease of temperature inherent in the speed of light c causes the nonlinear term to be more active that increases the amplitude of the rarefactive solitons and dampens the growth of compressive solitons for relatively low and high mass ratio Q’, respectively. The impact of higher initial streaming of the massive ions is observed to identify the point of maximum dust density N{sub d} to yield rarefactive relativistic solitons of maximum amplitude.
Acceleration and loss of relativistic electrons during small geomagnetic storms.
Anderson, B R; Millan, R M; Reeves, G D; Friedel, R H W
2015-12-16
Past studies of radiation belt relativistic electrons have favored active storm time periods, while the effects of small geomagnetic storms (Dst > -50 nT) have not been statistically characterized. In this timely study, given the current weak solar cycle, we identify 342 small storms from 1989 through 2000 and quantify the corresponding change in relativistic electron flux at geosynchronous orbit. Surprisingly, small storms can be equally as effective as large storms at enhancing and depleting fluxes. Slight differences exist, as small storms are 10% less likely to result in flux enhancement and 10% more likely to result in flux depletion than large storms. Nevertheless, it is clear that neither acceleration nor loss mechanisms scale with storm drivers as would be expected. Small geomagnetic storms play a significant role in radiation belt relativistic electron dynamics and provide opportunities to gain new insights into the complex balance of acceleration and loss processes.
Relativistic models for quasielastic electron and neutrino-nucleus scattering
Meucci Andrea
2012-12-01
Full Text Available Relativistic models developed within the framework of the impulse approximation for quasielastic (QE electron scattering and successfully tested in comparison with electron-scattering data have been extended to neutrino-nucleus scattering. Different descriptions of final-state interactions (FSI in the inclusive scattering are compared. In the relativistic Green’s function (RGF model FSI are described consistently with the exclusive scattering using a complex optical potential. In the relativistic mean field (RMF model FSI are described by the same RMF potential which gives the bound states. The results of the models are compared for electron and neutrino scattering and, for neutrino scattering, with the recently measured charged-current QE (CCQE MiniBooNE cross sections.
Correlation function and electronic spectral line broadening in relativistic plasmas
Douis S.
2013-01-01
Full Text Available The electrons dynamics and the time autocorrelation function Cee(t for the total electric microfield of the electrons on positive charge impurity embedded in a plasma are considered when the relativistic dynamic of the electrons is taken into account. We have, at first, built the effective potential governing the electrons dynamics. This potential obeys a nonlinear integral equation that we have solved numerically. Regarding the electron broadening of the line in plasma, we have found that when the plasma parameters change, the amplitude of the collision operator changes in the same way as the time integral of Cee(t. The electron-impurity interaction is taken at first time as screened Deutsh interaction and at the second time as Kelbg interaction. Comparisons of all interesting quantities are made with respect to the previous interactions as well as between classical and relativistic dynamics of electrons.
Avancini, S.S.; Marinelli, J.R. [Universidade Federal de Santa Catarina Florianopolis, Depto de Fisica - CFM, Florianopolis (Brazil); Carlson, B.V. [Instituto Tecnologico de Aeronautica, Sao Jose dos Campos (Brazil)
2013-06-15
Relativistic models for finite nuclei contain spurious center-of-mass motion in most applications for the nuclear many-body problem, where the nuclear wave function is taken as a single Slater determinant within a space-fixed frame description. We use the Peierls-Yoccoz projection method, previously developed for relativistic approaches together with a reparametrization of the coupling constants that fits binding energies and charge radius and apply our results to calculate elastic electron scattering monopole charge form factors for light nuclei. (orig.)
Cooling of Relativistic Electron-Beams
Bazylev, V. A.; Tulupov, A. V.
1993-01-01
A method of reducing the energy spread of an electron beam in a free-electron laser is suggested. The electron beam compression is based on a nonlinear mechanism of electron interactions with a ponderomotive wave in the presence of a constant and uniform magnetic field perpendicular to the electron
Optical principles of beam transport for relativistic electron cooling
A. Burov
2000-09-01
Full Text Available In conventional low energy electron coolers, the electron beam is immersed in a continuous solenoid, which provides a calm and tightly focused beam in a cooling section. While suitable for low energies, the continuity of the accompanying magnetic field is hardly realizable at relativistic energies. We consider the possibility of using an extended solenoid in the gun and the cooling section only, applying lumped focusing for the rest of the electron transport line.
Relativistic electron ring equilibrium with angular momentum spread
Croitoru, M.; Grecu, D. (Institutul de Fizica si Inginerie Nucleara, Bucharest (Romania))
1980-01-01
The equilibrium properties of a relativistic electron ring are determined by solving in a consistent way the Vlasov-Maxwell equations for a distribution function with an angular momentum spread. In the thin ring approximation there have been deduced general formulae for the electron density and the current density. A general theorem concerning the sharp form in space of the electron density is also obtained for the case of a microcanonical distribution function both in energy and angular momentum.
Parity Violating Electron Scattering in the Relativistic Eikonal Approximation
DONG Tie-Kuang; REN Zhong-Zhou
2008-01-01
The parity violating electron scattering is investigated in the relativistic Eikonal approximation. The parity violating asymmetry parameters for many isotopes are calculated. In calculations the proton and neutron densities are obtained from the relativistic mean-field theory. We take Ni isotopes as examples to analyse the behaviour of the parity violating asymmetry parameters. The results show that the parity violating asymmetry parameter is sensitive to the difference between the proton and neutron densities. The amplitude of the parity violating asymmetry parameter increases with the distance between the minima of proton and neutron form factors. Our results are useful for future parity violating electron scattering experiments. By comparing our results with experimental data one can test the validity of the relativistic mean-field theory in calculating the neutron densities of nuclei.
Radiation of relativistic electrons in a periodic wire structure
Soboleva, V.V., E-mail: sobolevaveronica@mail.ru; Naumenko, G.A.; Bleko, V.V.
2015-07-15
We present in this work the experimental investigation of the interaction of relativistic electron field with periodic wire structures. We used two types of the targets in experiments: flat wire target and sandwich wire target that represent the right triangular prism. The measurements were done in millimeter wavelength region (10–40 mm) on the relativistic electron beam with energy of 6.2 MeV in far-field zone. We showed that bunched electron beam passing near wire metamaterial prism generates coherent Cherenkov radiation. The experiments with flat wire target were carried out in two geometries. In the first geometry the electron beam passed close to the flat wire target surface. In the second case the electron beam passed through the flat wire structure with generation of a coherent backward transition radiation (CBTR). The comparison of the Cherenkov radiation intensity and BTR intensity from the flat wire target and from the flat conductive target (conventional BTR) was made.
Vayenas, C. G.; Fokas, A. S.; Grigoriou, D.
2016-08-01
We compute analytically the masses, binding energies and hamiltonians of gravitationally bound Bohr-type states via the rotating relativistic lepton model which utilizes the de Broglie wavelength equation in conjunction with special relativity and Newton's relativistic gravitational law. The latter uses the inertial-gravitational masses, rather than the rest masses, of the rotating particles. The model also accounts for the electrostatic charge- induced dipole interactions between a central charged lepton, which is usually a positron, with the rotating relativistic lepton ring. We use three rotating relativistic neutrinos to model baryons, two rotating relativistic neutrinos to model mesons, and a rotating relativistic electron neutrino - positron (or electron) pair to model the W± bosons. It is found that gravitationally bound ground states comprising three relativistic neutrinos have masses in the baryon mass range (∼⃒ 0.9 to 1 GeV/c2), while ground states comprising two neutrinos have masses in the meson mass range (∼⃒ 0.4 to 0.8 GeV/c2). It is also found that the rest mass values of quarks are in good agreement with the heaviest neutrino mass value of 0.05 eV/c2 and that the mass of W± bosons (∼⃒ 81 GeV/c2) corresponds to the mass of a rotating gravitationally confined e± — ve pair. A generalized expression is also derived for the gravitational potential energy of such relativistic Bohr-type structures.
Strong electromagnetic waves in a magnetized relativistic electron-positron plasma
Yu, M.Y.; Shukla, P.K.; Rao, N.N. (Bochum Univ. (Germany, F.R.). Inst. fuer Theoretische Physik)
1984-12-01
It is shown that in a strongly magnetized relativistic electron-positron plasma, strongly localized large amplitude circularly polarized electromagnetic wave pulses exist. The localization is due to relativistic mass variation as well as ponderomotive force effects. Three types of pulses are found analytically: the sharply spiked pulse in a strongly magnetized cold plasma, the smooth pulse in a weak magnetized warm plasma, and the moderately spiked pulse for a weakly magnetized cold plasma. The physical mechanisms giving rise to these pulses are distinct for each case. Possible implications of our investigation to pulsar radiation are discussed.
Gravitational mass of relativistic matter and antimatter
Kalaydzhyan, Tigran
2015-12-01
The universality of free fall, the weak equivalence principle (WEP), is a cornerstone of the general theory of relativity, the most precise theory of gravity confirmed in all experiments up to date. The WEP states the equivalence of the inertial, m, and gravitational, mg, masses and was tested in numerous occasions with normal matter at relatively low energies. However, there is no confirmation for the matter and antimatter at high energies. For the antimatter the situation is even less clear - current direct observations of trapped antihydrogen suggest the limits - 65 International Linear Collider (ILC) and Compact Linear Collider (CLIC).
The First Principle Formula of the Relativistic Heat Conductivity of Coulomb Electronic Plasmas
TIAN Chu-Shun; ZHANG Chi; LU Quan-Kang
2001-01-01
Making use of the relativistic BBGKY technique,the relativistic generalization of Landau collision integral is obtained.Furthermore,we calculate the relativistic hydrodynamic modes up to the second order in the hydrodynamic wave number.Combining Résibois' method,we present the first principle formula of the relativistic heat conductivity of Coulomb electronic plasmas for low-order corrections.
The Electron Trajectory in a Relativistic Femtosecond Laser Pulse
He Feng; Yu Wei; Lu Peixiang; Xu Han; Shen Baifei; Li Ruxin; Xu Zhizhan
2005-01-01
In this report, we start from Lagrange equation and analyze theoretically the electron dynamics in electromagnetic field. By solving the relativistic government equations of electron,the trajectories of an electron in plane laser pulse, focused laser pulse have been given for different initial conditions. The electron trajectory is determined by its initial momentum, the amplitude,spot size and polarization of the laser pulse. The optimum initial momentum of the electron for LSS (laser synchrotron source) is obtained. Linear polarized laser is more advantaged than circular polarized laser for generating harmonic radiation.
Precipitation of Relativistic Electrons from the Drift Loss Cone
Lorentzen, K. R.; Looper, M. D.; Blake, J. B.; Millan, R. M.; Smith, D. M.; Lin, R. P.
2001-12-01
On Jan. 22, 2000, the MAXIS (MeV Auroral X-ray and Spectroscopy) experiment observed a relativistic electron precipitation event using balloon-borne X-ray detectors. The X-ray spectrum from this event is consistent with atmospheric bremsstrahlung from precipitating electrons peaked between 2 and 3 MeV. This event occurred at L =3.8 in the duskside southern hemisphere, near the western edge of the South Atlantic Anomaly. Several minutes before the start of the balloon event, the SAMPEX satellite observed an intense relativistic electron microburst event in the dawnside northern hemisphere. Tracing the mirror point of electrons observed by SAMPEX indicates that some of these microburst electrons were located in the drift loss cone, and would have precipitated near the location of the balloon measurement. We model the electron drift and scatter in order to examine how the temporal structure and energy spectrum of the precipitating particles change as they drift around the Earth. These observations have implications for quantifying the loss of relativistic electrons from the radiation belts.
Indirect Relativistic Effect in Electron-Alkali-Atom Collision
LIU Yi-Bao; PANG Wen-Ning; DING Hai-Bing; SHANG Ren-Cheng
2005-01-01
@@ We present detailed studies on the differential cross section (DCS) and total cross section (TCS) in electronalkali-atom collision processes by using two types of distorted wave methods, the ordinary distorted wave method and the indirect-relativistic distorted wave method. We find that the indirect relativistic effect in the target atom can be neglected in the TCS calculation in the processes; however, with an increase of the atomic number, this effect becomes significant in the DCS calculation. Then, based on the density matrix theory, the orientation and alignment parameters of excited caesium P states scattered by electrons at low incident energy are calculated,and comparisons are made for the two series between the two methods. The results show that accordance is reached at scattering angles smaller than 45°, but considerable difference appears at angles larger than 45° due to the relativistic effect.
Waves in relativistic electron beam in low-density plasma
Sheinman, I.; Sheinman (Chernenco, J.
2016-11-01
Waves in electron beam in low-density plasma are analyzed. The analysis is based on complete electrodynamics consideration. Dependencies of dispersion laws from system parameters are investigated. It is shown that when relativistic electron beam is passed through low-density plasma surface waves of two types may exist. The first type is a high frequency wave on a boundary between the beam and neutralization area and the second type wave is on the boundary between neutralization area and stationary plasma.
A Nonlinear Model for Relativistic Electrons at Positive Temperature
Hainzl, Christian; Lewin, Mathieu; Seiringer, Robert
2008-01-01
We study the relativistic electron-positron field at positive temperature in the Hartree-Fock-approximation. We consider both the case with and without exchange term, and investigate the existence and properties of minimizers. Our approach is non-perturbative in the sense that the relevant electron subspace is determined in a self-consistent way. The present work is an extension of previous work by Hainzl, Lewin, S\\'er\\'e, and Solovej where the case of zero temperature was considered.
Quantum regime of a free-electron laser: relativistic approach
Kling, Peter; Sauerbrey, Roland; Preiss, Paul; Giese, Enno; Endrich, Rainer; Schleich, Wolfgang P.
2017-01-01
In the quantum regime of the free-electron laser, the dynamics of the electrons is not governed by continuous trajectories but by discrete jumps in momentum. In this article, we rederive the two crucial conditions to enter this quantum regime: (1) a large quantum mechanical recoil of the electron caused by the scattering with the laser and the wiggler field and (2) a small energy spread of the electron beam. In contrast to our recent approach based on nonrelativistic quantum mechanics in a co-moving frame of reference, we now pursue a model in the laboratory frame employing relativistic quantum electrodynamics.
Relativistic runaway electrons in tokamak plasmas
Jaspers, R.E.
1995-02-03
Runaway electrons are inherently present in a tokamak, in which an electric field is applied to drive a toroidal current. The experimental work is performed in the tokamak TEXTOR. Here runaway electrons can acquire energies of up to 30 MeV. The runaway electrons are studied by measuring their synchrotron radiation, which is emitted in the infrared wavelength range. The studies presented are unique in the sense that they are the first ones in tokamak research to employ this radiation. Hitherto, studies of runaway electrons revealed information about their loss in the edge of the discharge. The behaviour of confined runaways was still a terra incognita. The measurement of the synchrotron radiation allows a direct observation of the behaviour of runaway electrons in the hot core of the plasma. Information on the energy, the number and the momentum distribution of the runaway electrons is obtained. The production rate of the runaway electrons, their transport and the runaway interaction with plasma waves are studied. (orig./HP).
Coherent radiation of relativistic electrons in wire metamaterial
Soboleva, V.; Naumenko, G.; Bleko, V.
2016-07-01
We present in this work the experimental investigation of the interaction of relativistic electron field with wire metamaterial. The measurements of the spectral-angular characteristics of coherent radiation were done in millimeter wavelength region in far-field zone at the relativistic electron beam with energy of 6 MeV. Used target represent the right triangular prism that consist of periodic placed copper wires. We showed that bunched electron beam passing near wire metamaterial prism generates coherent Cherenkov radiation. Spectral angular characteristics of radiation from the wire target were compared with the characteristics of Cherenkov radiation generated in similar experimental conditions in a dielectric target (Teflon prism) that has the same form and sizes.
Radiative cooling of relativistic electron beams
Huang, Zhirong [Stanford Univ., CA (United States)
1998-05-01
Modern high-energy particle accelerators and synchrotron light sources demand smaller and smaller beam emittances in order to achieve higher luminosity or better brightness. For light particles such as electrons and positrons, radiation damping is a natural and effective way to obtain low emittance beams. However, the quantum aspect of radiation introduces random noise into the damped beams, yielding equilibrium emittances which depend upon the design of a specific machine. In this dissertation, the author attempts to make a complete analysis of the process of radiation damping and quantum excitation in various accelerator systems, such as bending magnets, focusing channels and laser fields. Because radiation is formed over a finite time and emitted in quanta of discrete energies, he invokes the quantum mechanical approach whenever the quasiclassical picture of radiation is insufficient. He shows that radiation damping in a focusing system is fundamentally different from that in a bending system. Quantum excitation to the transverse dimensions is absent in a straight, continuous focusing channel, and is exponentially suppressed in a focusing-dominated ring. Thus, the transverse normalized emittances in such systems can in principle be damped to the Compton wavelength of the electron, limited only by the Heisenberg uncertainty principle. In addition, he investigates methods of rapid damping such as radiative laser cooling. He proposes a laser-electron storage ring (LESR) where the electron beam in a compact storage ring repetitively interacts with an intense laser pulse stored in an optical resonator. The laser-electron interaction gives rise to rapid cooling of electron beams and can be used to overcome the space charge effects encountered in a medium energy circular machine. Applications to the designs of low emittance damping rings and compact x-ray sources are also explored.
Microwave Emission from Relativistic Electron Beams.
1983-12-23
the electrons an undulatory motion which effectively increases their velocity, and allows them to become synchronous with one of the fast TE or TM... undulatory motion. The device is illustrated schematically in Fig. 1. It comprises a smooth cylindrical cathode of radius rc enclosing a smooth coaxial
Chaotic Motion of Relativistic Electrons Driven by Whistler Waves
Khazanov, G. V.; Telnikhin, A. A.; Kronberg, Tatiana K.
2007-01-01
Canonical equations governing an electron motion in electromagnetic field of the whistler mode waves propagating along the direction of an ambient magnetic field are derived. The physical processes on which the equations of motion are based .are identified. It is shown that relativistic electrons interacting with these fields demonstrate chaotic motion, which is accompanied by the particle stochastic heating and significant pitch angle diffusion. Evolution of distribution functions is described by the Fokker-Planck-Kolmogorov equations. It is shown that the whistler mode waves could provide a viable mechanism for stochastic energization of electrons with energies up to 50 MeV in the Jovian magnetosphere.
Electron correlation within the relativistic no-pair approximation
Almoukhalalati, Adel; Knecht, Stefan; Jensen, Hans Jørgen Aa
2016-01-01
This paper addresses the definition of correlation energy within 4-component relativistic atomic and molecular calculations. In the nonrelativistic domain the correlation energy is defined as the difference between the exact eigenvalue of the electronic Hamiltonian and the Hartree-Fock energy....... In practice, what is reported is the basis set correlation energy, where the "exact" value is provided by a full Configuration Interaction (CI) calculation with some specified one-particle basis. The extension of this definition to the relativistic domain is not straightforward since the corresponding......-like correlation expression, whereas the corresponding CI correlation energy contains an additional relaxation term. We explore numerically our theoretical analysis by carrying out variational and perturbative calculations on the two-electron rare gas atoms with specially tailored basis sets...
X-ray harmonic comb from relativistic electron spikes
Pirozhkov, Alexander S; Esirkepov, Timur Zh; Ragozin, Eugene N; Faenov, Anatoly Ya; Pikuz, Tatiana A; Kawachi, Tetsuya; Sagisaka, Akito; Mori, Michiaki; Kawase, Keigo; Koga, James K; Kameshima, Takashi; Fukuda, Yuji; Chen, Liming; Daito, Izuru; Ogura, Koichi; Hayashi, Yukio; Kotaki, Hideyuki; Kiriyama, Hiromitsu; Okada, Hajime; Nishimori, Nobuyuki; Kondo, Kiminori; Kimura, Toyoaki; Tajima, Toshiki; Daido, Hiroyuki; Kato, Yoshiaki; Bulanov, Sergei V
2010-01-01
X-ray devices are far superior to optical ones for providing nanometre spatial and attosecond temporal resolutions. Such resolution is indispensable in biology, medicine, physics, material sciences, and their applications. A bright ultrafast coherent X-ray source is highly desirable, for example, for the diffractive imaging of individual large molecules, viruses, or cells. Here we demonstrate experimentally a new compact X-ray source involving high-order harmonics produced by a relativistic-irradiance femtosecond laser in a gas target. In our first implementation using a 9 Terawatt laser, coherent soft X-rays are emitted with a comb-like spectrum reaching the 'water window' range. The generation mechanism is robust being based on phenomena inherent in relativistic laser plasmas: self-focusing, nonlinear wave generation accompanied by electron density singularities, and collective radiation by a compact electric charge. The formation of singularities (electron density spikes) is described by the elegant mathem...
Relativistic electron flux enhancement at synchronous orbit during SEP event on July 14, 2000
赵华; 朱光武; 王世金; 高玉芬; 刘振兴
2002-01-01
Relativistic (E >1.6 MeV) electron flux enhancements during Solar Energetic Particle (SEP) events as observed by the synchronous FY-2 satellite at orbit located at 105°E are investigated. Energetic protons during SEP events heavily contaminate relativistic electron flux measurements. The ratio of the contamination in the original measurement of relativistic electron flux was over 30% during most of the SEP event on July 14, 2000. A method has been developed to eliminate the contamination caused by the energetic protons, and a "corrected" relativistic electron flux has been obtained. The "cleaned-up" relativistic electron flux measurement shows that relativistic electron flux enhancement at synchronous orbit is well correlated with SEP events during which the IMF Bz has some southward periods. The enhancement could arise as the transport of relativistic electrons from the upstream solar wind into synchronous orbit via the magnetotail.
A RELATIVISTIC QUASI-STATIC MODEL FOR ELECTRONS IN INTENSE LASER FIELDS
CHEN BAO-ZHEN
2001-01-01
A relativistic quasi-static model for the motion of the electrons in relativistic laser fields is proposed. Using the model, the recent experimental results about the generation of the hot electrons in relativistic laser fields can be fit quite well and the important role of the rescattering can be shown clearly.
Relativistic electrons from sparks in the laboratory
Østgaard, N; Nisi, R S; Gjesteland, T; Grøndahl, Ø; Skeltved, A; Lehtinen, N G; Mezentsev, A; Marisaldi, M; Kochkin, P
2016-01-01
Discharge experiments were carried out at the Eindhoven University of Technology in 2013. The experimental setup was designed to search for electrons produced in meter-scale sparks using a 1 MV Marx generator. Negative voltage was applied to the high voltage (HV) electrode. Five thin (1 mm) plastic detectors (5 $\\rm cm^2$ each) were distributed in various configurations close to the spark gap. Earlier studies have shown (for HV negative) that X-rays are produced when a cloud of streamers is developed 30-60 cm from the negative electrode. This indicates that the electrons producing the X-rays are also accelerated at this location, that could be in the strong electric field from counterstreamers of opposite polarity. Comparing our measurements with modeling results, we find that $\\sim$300 keV electrons produced about 30-60 cm from the negative electrode are the most likely source of our measurements. A statistical analysis of expected detection of photon bursts by these fiber detectors indicates that only 20%-4...
Electron correlation within the relativistic no-pair approximation
Almoukhalalati, Adel; Knecht, Stefan; Jensen, Hans Jørgen Aa.; Dyall, Kenneth G.; Saue, Trond
2016-08-01
This paper addresses the definition of correlation energy within 4-component relativistic atomic and molecular calculations. In the nonrelativistic domain the correlation energy is defined as the difference between the exact eigenvalue of the electronic Hamiltonian and the Hartree-Fock energy. In practice, what is reported is the basis set correlation energy, where the "exact" value is provided by a full Configuration Interaction (CI) calculation with some specified one-particle basis. The extension of this definition to the relativistic domain is not straightforward since the corresponding electronic Hamiltonian, the Dirac-Coulomb Hamiltonian, has no bound solutions. Present-day relativistic calculations are carried out within the no-pair approximation, where the Dirac-Coulomb Hamiltonian is embedded by projectors eliminating the troublesome negative-energy solutions. Hartree-Fock calculations are carried out with the implicit use of such projectors and only positive-energy orbitals are retained at the correlated level, meaning that the Hartree-Fock projectors are frozen at the correlated level. We argue that the projection operators should be optimized also at the correlated level and that this is possible by full Multiconfigurational Self-Consistent Field (MCSCF) calculations, that is, MCSCF calculations using a no-pair full CI expansion, but including orbital relaxation from the negative-energy orbitals. We show by variational perturbation theory that the MCSCF correlation energy is a pure MP2-like correlation expression, whereas the corresponding CI correlation energy contains an additional relaxation term. We explore numerically our theoretical analysis by carrying out variational and perturbative calculations on the two-electron rare gas atoms with specially tailored basis sets. In particular, we show that the correlation energy obtained by the suggested MCSCF procedure is smaller than the no-pair full CI correlation energy, in accordance with the underlying
Towards laboratory produced relativistic electron-positron pair plasmas
Chen, Hui; Meyerhofer, D. D.; Wilks, S. C.; Cauble, R.; Dollar, F.; Falk, K.; Gregori, G.; Hazi, A.; Moses, E. I.; Murphy, C. D.; Myatt, J.; Park, J.; Seely, J.; Shepherd, R.; Spitkovsky, A.; Stoeckl, C.; Szabo, C. I.; Tommasini, R.; Zulick, C.; Beiersdorfer, P.
2011-12-01
We review recent experimental results on the path to producing electron-positron pair plasmas using lasers. Relativistic pair-plasmas and jets are believed to exist in many astrophysical objects and are often invoked to explain energetic phenomena related to Gamma Ray Bursts and Black Holes. On earth, positrons from radioactive isotopes or accelerators are used extensively at low energies (sub-MeV) in areas related to surface science positron emission tomography and basic antimatter science. Experimental platforms capable of producing the high-temperature pair-plasma and high-flux jets required to simulate astrophysical positron conditions have so far been absent. In the past few years, we performed extensive experiments generating positrons with intense lasers where we found that relativistic electron and positron jets are produced by irradiating a solid gold target with an intense picosecond laser pulse. The positron temperatures in directions parallel and transverse to the beam both exceeded 0.5 MeV, and the density of electrons and positrons in these jets are of order 10 16 cm -3 and 10 13 cm -3, respectively. With the increasing performance of high-energy ultra-short laser pulses, we expect that a high-density, up to 10 18 cm -3, relativistic pair-plasma is achievable, a novel regime of laboratory-produced hot dense matter.
Relativistic electron mirrors from high intensity laser nanofoil interactions
Kiefer, Daniel
2012-12-21
The reflection of a laser pulse from a mirror moving close to the speed of light could in principle create an X-ray pulse with unprecedented high brightness owing to the increase in photon energy and accompanying temporal compression by a factor of 4γ{sup 2}, where γ is the Lorentz factor of the mirror. While this scheme is theoretically intriguingly simple and was first discussed by A. Einstein more than a century ago, the generation of a relativistic structure which acts as a mirror is demanding in many different aspects. Recently, the interaction of a high intensity laser pulse with a nanometer thin foil has raised great interest as it promises the creation of a dense, attosecond short, relativistic electron bunch capable of forming a mirror structure that scatters counter-propagating light coherently and shifts its frequency to higher photon energies. However, so far, this novel concept has been discussed only in theoretical studies using highly idealized interaction parameters. This thesis investigates the generation of a relativistic electron mirror from a nanometer foil with current state-of-the-art high intensity laser pulses and demonstrates for the first time the reflection from those structures in an experiment. To achieve this result, the electron acceleration from high intensity laser nanometer foil interactions was studied in a series of experiments using three inherently different high power laser systems and free-standing foils as thin as 3nm. A drastic increase in the electron energies was observed when reducing the target thickness from the micrometer to the nanometer scale. Quasi-monoenergetic electron beams were measured for the first time from ultrathin (≤5nm) foils, reaching energies up to ∝35MeV. The acceleration process was studied in simulations well-adapted to the experiments, indicating the transition from plasma to free electron dynamics as the target thickness is reduced to the few nanometer range. The experience gained from those
Relativistic electronic dressing in laser-assisted ionization of atomic hydrogen by electron impact
Attaourti, Y
2004-01-01
Within the framework of the coplanar binary geometry where it is justified to use plane wave solutions for the study of the $(e,2e)$ reaction and in the presence of a circularly polarized laser field, we introduce as a first step the DVRPWBA1 (Dirac-Volkov Plane Wave Born Approximation1) where we take into account only the relativistic dressing of the incident and scattered electrons. Then, we introduce the DVRPWBA2 (Dirac-Volkov Plane Wave Born Approximation2) where we take totally into account the relativistic dressing of the incident, scattered and ejected electrons. We then compare the corresponding triple differential cross sections for laser-assisted ionization of atomic hydrogen by electron impact both for the non relativistic and the relativistic regime.
OTR from Non-Relativistic Electrons
Bal, C; Chevallay, E; Lefèvre, T; Suberlucq, Guy
2003-01-01
The CLIC Test Facility 3 (CTF3) injector will provide pulsed beams of high average current; 5A over 1.56µs at 140keV. For transverse beam sizes of the order of 1mm, as foreseen, this implies serious damage to the commonly used scintillating screens. Optical Transition Radiation from thermally resistant radiators represents a possible alternative. In this context, the backward OTR radiation emitted from an aluminium screen by a 80keV, 60nC, 4ns electron pulse has been investigated. The experimental results are in good agreement with the theoretical expectations, indicating a feeble light intensity distributed over a large solid angle. Our conclusions for the design of the CTF3 injector profile monitor are also given.
2008-01-01
The space particle component detector on Fengyun-1 satellite which works at the sun-synchronous orbit of about 870 km altitude has detected relativistic electrons for a long time. In comparison with the SAMPEX satellite observations during 1999 -2004, the relativistic electron data from Fengyun-1 satellite from June 1999 to 2005 are used to analyze the relativistic electron enhancement (REE) events at the low earth orbit, and the possible correlation among REE events at the low earth orbit, high-speed solar wind and geomagnetic storms is discussed. The statistical result presents that 45 REE events are found in total during this time period, and the strong REE events with the maximum daily average flux > 400 cm?2·sr?1·s?1 occur mostly during the transition period from solar maximum to solar minimum. Among these 45 REE events, four strong REE events last a longer time period from 26- to 51-day and correlate closely with high speed solar wind and strong geo- magnetic storms. Meanwhile, several strong geomagnetic storms occur continu- ously before these REE events, and these continuous geomagnetic storms would be an important factor causing these long-lasting strong REE events. The correlation analysis for overall 45 events indicates that the strength of the REE events corre- lates with the solar wind speed and the strength of the geomagnetic storm, and the correlation for strong REE events is much stronger than that for weak REE events.
Strong electron-scale instability in relativistic shear flows
Alves, Eduardo Paulo; Grismayer, Thomas; Fonseca, Ricardo; Silva, Luis
2013-10-01
Collisionless shear-driven plasma instabilities have recently been shown to be capable of generating strong and large-scale magnetic fields and may therefore play an important role in relativistic astrophysical outflows. We present a new collisionless shear-driven plasma instability, which operates in the plane transverse to the Kelvin Helmholtz instability (KHI). We develop the linear stability analysis of electromagnetic modes in the transverse plane and find that the growth rate of this instability is greater than the competing KHI in relativistic shears. The analytical results are confirmed with 2D particle-in-cell (PIC) simulations. Simulations also reveal the nonlinear evolution of the instability which leads to the development of mushroom-like electron-density structures, similar to the Rayleigh Taylor instability. Finally, the interplay between the competing instabilities is investigated in 3D PIC simulations.
Induced Compton Scattering by Relativistic Electrons in Magnetized Astrophysical Plasmas.
Sincell, Mark William
1994-01-01
The effects of stimulated scattering on high brightness temperature radiation are studied in two important contexts. In the first case, we assume that the radiation is confined to a collimated beam traversing a relativistically streaming magnetized plasma. When the plasma is cold in the bulk frame, stimulated scattering is only significant if the angle between the photon motion and the plasma velocity is less than gamma^{-1} , where gamma is the bulk Lorentz factor. Under the assumption that the center of the photon beam is parallel to the bulk motion, we calculate the scattering rate as a function of the angular spread of the beam and gamma. Magnetization changes the photon recoil, without which stimulated scattering has no effect. It also introduces a strong dependence on frequency and polarization: if the photon frequency matches the electron cyclotron frequency, the scattering rate of photons polarized perpendicular to the magnetic field can be substantially enhanced relative to Thomson, and if the photon frequency is much less than the cyclotron frequency the scattering is suppressed. Applying these calculations to pulsars, we find that stimulated scattering of the radio beam in the magnetized wind believed to exist outside the light cylinder can substantially alter the spectrum and polarization state of the radio signal. We suggest that the scattering rate is so high in some pulsars that the ability of the radio signal to penetrate the pulsar magnetosphere requires modification of either the conventional model of the magnetosphere or assumptions about the effects of stimulated scattering upon a beam. In the second case, we present a model of the radio emission from synchrotron self-absorbed sources, including the effects of induced Compton scattering by the relativistic electrons in the source. Order of magnitude estimates show that stimulated scattering becomes the dominant absorption process when (kTB/m ec^2)tau_{T }_sp{~}> 0.1. Numerical simulations
Electron Heating in a Relativistic, Weibel-Unstable Plasma
Kumar, Rahul; Gedalin, Michael
2015-01-01
The dynamics of two initially unmagnetized relativistic counter-streaming homogeneous ion-electron plasma beams are simulated in two dimensions using the particle-in-cell (PIC) method. It is shown that current filaments, which form due to the Weibel instability, develop a large scale longitudinal electric field in the direction opposite to the current carried by the filaments as predicted by theory. Fast moving ions in the current filaments decelerate due to this longitudinal electric field. The same longitudinal electric field, which is partially inductive and partially electrostatic, is identified as the main source of acceleration of electrons in the current filaments. The transverse electric field, though larger than the longitudinal one, is shown to play a smaller role in heating electrons, contrary to previous claims. It is found that, in 1D, the electrons become strongly magnetized and are \\textit{not} accelerated beyond their initial kinetic energy. Rather, the heating of the electrons is enhanced by ...
`Relativistic' corrections to the mass of a plucked guitar string
Kolodrubetz, Michael; Polkovnikov, Anatoli
Quantum systems respond non-adiabaticity when parameters controlling them are ramped at a finite rate. If the parameters themselves are dynamical - for instance the position of a box that defines the boundary of a quantum field - the feedback of these excitations gives rise to effective Newtonian equations of motion for the parameter. For the age old problem of photons in a box, this correction gives rise to a mass proportional to the energy of the photons. We show that a similar correction arises for a classical guitar string plucked with energy E; moving clamps at the ends of the string requires inertial mass m = 2 E /cs2 , where cs is the speed of sound. This quasi-relativistic effect should be observable in freshman physics level experiments. We then comment on how these simple methods have been readily extended to treat problems such as ramps and quenches of strongly-interacting superconductors and dynamical trapping near a quantum critical point.
Microbunching of relativistic electrons using a two-frequency laser
Gordon, D.; Clayton, C. E.; Katsouleas, T.; Mori, W. B.; Joshi, C.
1998-01-01
A high power two-frequency laser can be used to modulate the axial momentum of a copropagating relativistic electron beam. The net work done on each electron is accounted for almost entirely by the axial electric field of the laser even when approaching the one-dimensional limit. After interacting with the laser, the electron beam can be bunched either by a long drift space or a dispersive optic. We give an example in which a 2.5-TW CO2 laser and a chicane compressor are used to transform a constant stream of 16-MeV electrons into a train of 60-fs microbunches, each containing 10 pC of charge.
Vacuum laser acceleration of relativistic electrons using plasma mirror injectors
Thévenet, M; Kahaly, S; Vincenti, H; Vernier, A; Quéré, F; Faure, J
2015-01-01
Accelerating particles to relativistic energies over very short distances using lasers has been a long standing goal in physics. Among the various schemes proposed for electrons, vacuum laser acceleration has attracted considerable interest and has been extensively studied theoretically because of its appealing simplicity: electrons interact with an intense laser field in vacuum and can be continuously accelerated, provided they remain at a given phase of the field until they escape the laser beam. But demonstrating this effect experimentally has proved extremely challenging, as it imposes stringent requirements on the conditions of injection of electrons in the laser field. Here, we solve this long-standing experimental problem for the first time by using a plasma mirror to inject electrons in an ultraintense laser field, and obtain clear evidence of vacuum laser acceleration. With the advent of PetaWatt class lasers, this scheme could provide a competitive source of very high charge (nC) and ultrashort rela...
Simulation of relativistically colliding laser-generated electron flows
Yang, Xiaohu; Sarri, Gianluca; Borghesi, Marco
2012-01-01
The plasma dynamics resulting from the simultaneous impact, of two equal, ultra-intense laser pulses, in two spatially separated spots, onto a dense target is studied via particle-in-cell (PIC) simulations. The simulations show that electrons accelerated to relativistic speeds, cross the target and exit at its rear surface. Most energetic electrons are bound to the rear surface by the ambipolar electric field and expand along it. Their current is closed by a return current in the target, and this current configuration generates strong surface magnetic fields. The two electron sheaths collide at the midplane between the laser impact points. The magnetic repulsion between the counter-streaming electron beams separates them along the surface normal direction, before they can thermalize through other beam instabilities. This magnetic repulsion is also the driving mechanism for the beam-Weibel (filamentation) instability, which is thought to be responsible for magnetic field growth close to the internal shocks of ...
Relativistic collision rate calculations for electron-air interactions
Graham, G. [EG and G Energy Measurements, Inc., Los Alamos, NM (United States); Roussel-Dupre, R. [Los Alamos National Lab., NM (United States). Space Science and Technologies
1992-12-16
The most recent data available on differential cross sections for electron-air interactions are used to calculate the avalanche, momentum transfer, and energy loss rates that enter into the fluid equations. Data for the important elastic, inelastic, and ionizing processes are generally available out to electron energies of 1--10 kev. Prescriptions for extending these cross sections to the relativistic regime are presented. The angular dependence of the cross sections is included where data is available as is the doubly differential cross section for ionizing collisions. The collision rates are computed by taking moments of the Boltzmann collision integrals with the assumption that the electron momentum distribution function is given by the Juettner distribution function which satisfies the relativistic H- theorem and which reduces to the familiar Maxwellian velocity distribution in the nonrelativistic regime. The distribution function is parameterized in terms of the electron density, mean momentum, and thermal energy and the rates are therefore computed on a two-dimensional grid as a function of mean kinetic energy and thermal energy.
Maroof, R. [Department of Physics, Abdul Wali Khan University, Mardan 23200 (Pakistan); Department of Physics, University of Peshawar, Peshawar 25000 (Pakistan); National Center for Physics (NCP) at QAU Campus, Shahdra Valley Road, Islamabad 44000 (Pakistan); Ali, S. [National Center for Physics (NCP) at QAU Campus, Shahdra Valley Road, Islamabad 44000 (Pakistan); Mushtaq, A. [Department of Physics, Abdul Wali Khan University, Mardan 23200 (Pakistan); National Center for Physics (NCP) at QAU Campus, Shahdra Valley Road, Islamabad 44000 (Pakistan); Qamar, A. [Department of Physics, University of Peshawar, Peshawar 25000 (Pakistan)
2015-11-15
Linear properties of high and low frequency waves are studied in an electron-positron-ion (e-p-i) dense plasma with spin and relativity effects. In a low frequency regime, the magnetohydrodynamic (MHD) waves, namely, the magnetoacoustic and Alfven waves are presented in a magnetized plasma, in which the inertial ions are taken as spinless and non-degenerate, whereas the electrons and positrons are treated quantum mechanically due to their smaller mass. Quantum corrections associated with the spin magnetization and density correlations for electrons and positrons are re-considered and a generalized dispersion relation for the low frequency MHD waves is derived to account for relativistic degeneracy effects. On the basis of angles of propagation, the dispersion relations of different modes are discussed analytically in a degenerate relativistic plasma. Numerical results reveal that electron and positron relativistic degeneracy effects significantly modify the dispersive properties of MHD waves. Our present analysis should be useful for understanding the collective interactions in dense astrophysical compact objects, like, the white dwarfs and in atmosphere of neutron stars.
Magnetic field modification to the relativistic runaway electron avalanche length
Cramer, E. S.; Dwyer, J. R.; Rassoul, H. K.
2016-11-01
This paper explores the impact of the geomagnetic field on the relativistic runaway electron avalanche length, λe-. Coleman and Dwyer (2006) developed an analytical fit to Monte Carlo simulations using the Runaway Electron Avalanche Model. In this work, we repeat this process but with the addition of the geomagnetic field in the range of [100,900]/n μT, where n is the ratio of the density of air at altitude to the sea level density. As the ambient electric field approaches the runaway threshold field (Eth≈284 kV/m sea level equivalent), it is shown that the magnetic field has an impact on the orientation of the resulting electron beam. The runaway electrons initially follow the vertically oriented electric field but then are deflected in the v × B direction, and as such, the electrons experience more dynamic friction due to the increase in path length. This will be shown to result in a difference in the avalanche length from the case where B = 0. It will also be shown that the average energy of the runaway electrons will decrease while the required electric field to produce runaway electrons increases. This study is also important in understanding the physics of terrestrial gamma ray flashes (TGFs). Not only will this work impact relativistic feedback rates determined from simulations, it may also be useful in studying spectroscopy of TGFs observed from balloon and aircraft measurements. These models may also be used in determining beaming properties of TGFs originating in the tropical regions seen from orbiting spacecraft.
Undamped relativistic magnetoplasmons in lossy two-dimensional electron systems
Volkov, V. A.; Zabolotnykh, A. A.
2016-10-01
We address electrodynamic effects in plasma oscillations of a lossy 2D electron system whose dc 2D conductivity σ0 is comparable to the speed of light c . We argue that the perpendicular constant magnetic field B causes astonishing features of magnetoplasma dynamics. We show that plasmon-polariton spectra can be classified using a "relativistic" phase diagram σ0/c versus B . An extraordinarily low damping branch in magnetoplasmon-polariton spectra emerges at two phases of this diagram. Some magnetoplasmons at these phases are predicted to be undamped waves.
Undamped relativistic magnetoplasmons in lossy two-dimensional electron systems
Volkov, V A
2016-01-01
We address electrodynamic effects in plasma oscillations of a lossy 2D electron system whose dc 2D conductivity is comparable to the speed of light. We argue that the perpendicular dc magnetic field B causes astonishing features of magnetoplasma dynamics. We show that plasmon-polariton spectra can be classified using a "relativistic" phase diagram 2D conductivity divided by the speed of light versus B. A novel, extraordinarily low damping branch in magnetoplasmon-polariton spectra emerges at two phases of this diagram. Some magnetoplasmons at these phases are predicted to be undamped waves.
Excitement tem-horn antenna by impulsive relativistic electron beam
Balakirev, V A; Egorov, A M; Lonin, Y F
2000-01-01
In the given operation the opportunity of reception powerful electromagnetic irradiation (EMI) is observationally explored by excitation by a impulsive relativistic electronic beam (IREB) of a TEM-horn antenna. It is revealed, that at such expedient of excitation of the TEM-horn antenna, the signal of radiation of the antenna contains three various components caused by oscillation of radiation by forward front IREB, high-voltage discharge between plates irradiation of TEM-horn antenna a and resonant properties of the antenna devices.
Extended quasiparticle approximation for relativistic electrons in plasmas
V.G.Morozov
2006-01-01
Full Text Available Starting with Dyson equations for the path-ordered Green's function, it is shown that the correlation functions for relativistic electrons (positrons in a weakly coupled non-equilibrium plasmas can be decomposed into sharply peaked quasiparticle parts and off-shell parts in a rather general form. To leading order in the electromagnetic coupling constant, this decomposition yields the extended quasiparticle approximation for the correlation functions, which can be used for the first principle calculation of the radiation scattering rates in QED plasmas.
Soft X-ray harmonic comb from relativistic electron spikes
Pirozhkov, A S; Esirkepov, T Zh; Gallegos, P; Ahmed, H; Ragozin, E N; Faenov, A Ya; Pikuz, T A; Kawachi, T; Sagisaka, A; Koga, J K; Coury, M; Green, J; Foster, P; Brenner, C; Dromey, B; Symes, D R; Mori, M; Kawase, K; Kameshima, T; Fukuda, Y; Chen, L; Daito, I; Ogura, K; Hayashi, Y; Kotaki, H; Kiriyama, H; Okada, H; Nishimori, N; Imazono, T; Kondo, K; Kimura, T; Tajima, T; Daido, H; Rajeev, P; McKenna, P; Borghesi, M; Neely, D; Kato, Y; Bulanov, S V
2012-01-01
We demonstrate a new high-order harmonic generation mechanism reaching the `water window' spectral region in experiments with multi-terawatt femtosecond lasers irradiating gas jets. A few hundred harmonic orders are resolved, giving uJ/sr pulses. Harmonics are collectively emitted by an oscillating electron spike formed at the joint of the boundaries of a cavity and bow wave created by a relativistically self-focusing laser in underdense plasma. The spike sharpness and stability are explained by catastrophe theory. The mechanism is corroborated by particle-in-cell simulations.
Lopez, Rodrigo A.; Munoz, Victor [Departamento de Fisica, Facultad de Ciencias, Universidad de Chile, Casilla 653, Santiago (Chile); Asenjo, Felipe A. [Institute for Fusion Studies, University of Texas at Austin, Austin, Texas 78712 (United States); Alejandro Valdivia, J. [Departamento de Fisica, Facultad de Ciencias, Universidad de Chile, Casilla 653, Santiago (Chile); Centro para el Desarrollo de la Nanociencia y la Nanotecnologia, CEDENNA, Santiago (Chile)
2012-08-15
The nonlinear evolution of a circularly polarized electromagnetic wave in an electron-positron plasma propagating along a constant background magnetic field is considered, by studying its parametric decays. Relativistic effects, of the particle motion in the wave field and of the plasma temperature, are included to obtain the dispersion relation of the decays. The exact dispersion relation of the pump wave has been previously calculated within the context of a relativistic fluid theory and presents two branches: an electromagnetic and an Alfven one. We investigate the parametric decays for the pump wave in these two branches, including the anomalous dispersion zone of the Alfven branch where the group velocity is negative. We solve the nonlinear dispersion relation for different pump wave amplitudes and plasma temperatures, finding various resonant and nonresonant wave couplings. We are able to identify these couplings and study their behavior as we modify the plasma parameters. Some of these couplings are suppressed for larger amplitudes or temperatures. We also find two kinds of modulational instabilities, one involving two sideband daughter waves and another involving a forward-propagating electroacoustic mode and a sideband daughter wave.
Electron acceleration and high harmonic generation by relativistic surface plasmons
Cantono, Giada; Luca Fedeli Team; Andrea Sgattoni Team; Andrea Macchi Team; Tiberio Ceccotti Team
2016-10-01
Intense, short laser pulses with ultra-high contrast allow resonant surface plasmons (SPs) excitation on solid wavelength-scale grating targets, opening the way to the extension of Plasmonics in the relativistic regime and the manipulation of intense electromagnetic fields to develop new short, energetic, laser-synchronized radiation sources. Recent theoretical and experimental studies have explored the role of SP excitation in increasing the laser-target coupling and enhancing ion acceleration, high-order harmonic generation and surface electron acceleration. Here we present our results on SP driven electron acceleration from grating targets at ultra-high laser intensities (I = 5 ×1019 W/cm2, τ = 25 fs). When the resonant condition for SP excitation is fulfilled, electrons are emitted in a narrow cone along the target surface, with a total charge of about 100 pC and energy spectra peaked around 5 MeV. Distinguishing features of the resonant process were investigated by varying the incidence angle, grating type and with the support of 3D PIC simulations, which closely reproduced the experimental data. Open challenges and further measurements on high-order harmonic generation in presence of a relativistic SP will also be discussed.
Pressure of Degenerate and Relativistic electrons in a superhigh magnetic field
Gao, Zhi Fu; He, Peng Qiu; Jie, Du Yuan
2013-01-01
Based on our previous work, we deduce a general formula for pressure of degenerate and relativistic electrons,Pe, which is suitable for superhigh magnetic fields, discuss the quantization of Landau levels of electrons, and consider the quantum electrodynam-ic(QED) effects on the equations of states (EOSs) for different matter systems. The main conclusions are as follows:Pe is related to the magnetic field B, matter density ?, and electron fraction Ye ; the stronger the magnetic field, the higher the electron pressure becomes; the high electron pressure could be caused by high Fermi energy of electrons in a superhigh magnetic field; compared with a common radio pulsar, a magnetar could be a more compact oblate spheroid-like deformed neutron star due to the anisotropic total pressure; and an increase in the maximum mass of a magnetar is expected because of the positive contribution of the magnetic field energy to the EOS of the star.
Transverse electron-scale instability in relativistic shear flows
Alves, E P; Fonseca, R A; Silva, L O
2015-01-01
Electron-scale surface waves are shown to be unstable in the transverse plane of a shear flow in an initially unmagnetized plasma, unlike in the (magneto)hydrodynamics case. It is found that these unstable modes have a higher growth rate than the closely related electron-scale Kelvin-Helmholtz instability in relativistic shears. Multidimensional particle-in-cell simulations verify the analytic results and further reveal the emergence of mushroom-like electron density structures in the nonlinear phase of the instability, similar to those observed in the Rayleigh Taylor instability despite the great disparity in scales and different underlying physics. Macroscopic ($\\gg c/\\omega_{pe}$) fields are shown to be generated by these microscopic shear instabilities, which are relevant for particle acceleration, radiation emission and to seed MHD processes at long time-scales.
Transmission of Megawatt Relativistic Electron Beams Through Millimeter Apertures
Alarcon, R; Benson, S V; Bertozzi, W; Boyce, J R; Cowan, R; Douglas, D; Evtushenko, P; Fisher, P; Ihloff, E; Kalantarians, N; Kelleher, A; Legg, R; Milner, R G; Neil, G R; Ou, L; Schmookler, B; Tennant, C; Tschalaer, C; Williams, G P; Zhang, S
2013-01-01
High power, relativistic electron beams from energy recovery linacs have great potential to realize new experimental paradigms for pioneering innovation in fundamental and applied research. A major design consideration for this new generation of experimental capabilities is the understanding of the halo associated with these bright, intense beams. In this Letter, we report on measurements performed using the 100 MeV, 430 kWatt CW electron beam from the energy recovery linac at the Jefferson Laboratory's Free Electron Laser facility as it traversed a set of small apertures in a 127 mm long aluminum block. Thermal measurements of the block together with neutron measurements near the beam-target interaction point yielded a consistent understanding of the beam losses. These were determined to be 3 ppm through a 2 mm diameter aperture and were maintained during a 7 hour continuous run.
Spontaneous radiation from relativistic electrons in a tapered undulator
Bosco, P.; Colson, W. B.
1983-01-01
The spectrum, angular distribution, polarization, and coherence properties of the radiation emitted by relativistic electrons undulating through a quasiperiodic tapered magnetic field are studied. Tapering the wavelength and/or field strength along the undulator's axis has the effect of spreading the spectral line to higher frequencies; interference over this broader spectral range results in a more complex line shape. The angular dependence, on the other hand, is not affected by the amount of taper. The polarization of the radiation in the forward direction is determined by the transverse polarization of the undulator, but the polarization changes off axis. The radiation patterns predicted here are distinct from those of untapered undulators and their detection is now feasible. They will provide useful diagnostics of electron trajectories and threshold behavior in free-electron-laser oscillators using tapered undulators.
Hot-electron refluxing enhanced relativistic transparency of overdense plasmas
Yu, Yong; Chen, Zi-Yu; Wang, Jia-Xiang; Zhu, Wen-Jun
2013-01-01
A new phenomenon of enhancing the relativistic transparency of overdense plasmas by the influence of hot-electron refluxing has been found via particle-in-cell simulations. When a p-polarized laser pulse, with intensity below the self-induced-transparency (SIT) threshold, obliquely irradiates a thin overdense plasma, the initially opaque plasma would become transparent after a time interval which linearly relies on the thickness of the plasma. This phenomenon can be interpreted by the influence of hot-electron refluxing. As the laser intensity is higher than the SIT threshold, the penetration velocity of the laser in the plasma is enhanced when the refluxing is presented. Simulation data with ion motion considered is also consistent with the assumption that hot-electron refluxing enhances transparency. These results have potential applications in laser shaping.
YANG XiaoChao; WANG Shidin
2008-01-01
The space particle component detector on Fengyun-1 satellite which works at the sun-synchronous orbit of about 870 km altitude has detected relativistic electrons for a long time.In comparison with the SAMPEX satellite observations during 1999--2004,the relativistic electron data from Fengyun-1 satellite from June 1999 to 2005 are used to analyze the relativistic electron enhancement (REE) events at the low earth orbit,and the possible correlation among REE events at the low earth orbit,high-speed solar wind and geomagnetic storms is discussed.The statistical result presents that 45 REE events are found in total during this time period,and the strong REE events with the maximum daily average flux > 400 cm-2.sr-1.s-1 occur mostly during the transition period from solar maximum to solar minimum.Among these 45 REE events,four strong REE events last a longer time period from 26- to 51-day and correlate closely with high speed solar wind and strong geo-magnetic storms.Meanwhile,several strong geomagnetic storms occur continu-ously before these REE events,and these continuous geomagnetic storms would be an important factor causing these long-lasting strong REE events.The correlation analysis for overall 45 events indicates that the strength of the REE events corre-lates with the solar wind speed and the strength of the geomagnetic storm,and the correlation for strong REE events is much stronger than that for weak REE events.
Electron Heating in a Relativistic, Weibel-unstable Plasma
Kumar, Rahul; Eichler, David; Gedalin, Michael
2015-06-01
The dynamics of two initially unmagnetized relativistic counter-streaming homogeneous ion-electron plasma beams are simulated in two dimensions (2D) using the particle-in-cell (PIC) method. It is shown that current filaments, which form due to the Weibel instability, develop a large-scale longitudinal electric field in the direction opposite to the current carried by the filaments as predicted by theory. This field, which is partially inductive and partially electrostatic, is identified as the main source of net electron acceleration, greatly exceeding that due to magnetic field decay at later stages. The transverse electric field, although larger than the longitudinal field, is shown to play a smaller role in heating electrons, contrary to previous claims. It is found that in one dimension, the electrons become strongly magnetized and are not accelerated beyond their initial kinetic energy. Rather, the heating of the electrons is enhanced by the bending and break up of the filaments, which releases electrons that would otherwise be trapped within a single filament and slow the development of the Weibel instability (i.e., the magnetic field growth) via induction as per Lenz’s law. In 2D simulations, electrons are heated to about one quarter of the initial kinetic energy of ions. The magnetic energy at maximum is about 4%, decaying to less than 1% by the end of the simulation. The ions are found to gradually decelerate until the end of the simulation, by which time they retain a residual anisotropy of less than 10%.
ELECTRON HEATING IN A RELATIVISTIC, WEIBEL-UNSTABLE PLASMA
Kumar, Rahul; Eichler, David; Gedalin, Michael [Physics Department, Ben-Gurion University, Be’er-Sheba 84105 (Israel)
2015-06-20
The dynamics of two initially unmagnetized relativistic counter-streaming homogeneous ion–electron plasma beams are simulated in two dimensions (2D) using the particle-in-cell (PIC) method. It is shown that current filaments, which form due to the Weibel instability, develop a large-scale longitudinal electric field in the direction opposite to the current carried by the filaments as predicted by theory. This field, which is partially inductive and partially electrostatic, is identified as the main source of net electron acceleration, greatly exceeding that due to magnetic field decay at later stages. The transverse electric field, although larger than the longitudinal field, is shown to play a smaller role in heating electrons, contrary to previous claims. It is found that in one dimension, the electrons become strongly magnetized and are not accelerated beyond their initial kinetic energy. Rather, the heating of the electrons is enhanced by the bending and break up of the filaments, which releases electrons that would otherwise be trapped within a single filament and slow the development of the Weibel instability (i.e., the magnetic field growth) via induction as per Lenz’s law. In 2D simulations, electrons are heated to about one quarter of the initial kinetic energy of ions. The magnetic energy at maximum is about 4%, decaying to less than 1% by the end of the simulation. The ions are found to gradually decelerate until the end of the simulation, by which time they retain a residual anisotropy of less than 10%.
Relativistic electron beam driven longitudinal wake-wave breaking in a cold plasma
Bera, Ratan Kumar; Sengupta, Sudip; Das, Amita
2016-01-01
Space-time evolution of relativistic electron beam driven wake-field in a cold, homogeneous plasma, is studied using 1D-fluid simulation techniques. It is observed that the wake wave gradu- ally evolves and eventually breaks, exhibiting sharp spikes in the density profile and sawtooth like features in the electric field profile [1]. It is shown here that the excited wakefield is a longitudi- nal Akhiezer-Polovin mode [2] and its steepening (breaking) can be understood in terms of phase mixing of this mode, which arises because of relativistic mass variation effects. Further the phase mixing time (breaking time) is studied as a function of beam density and beam velocity and is found to follow the well known scaling presented in ref.[3].
Maximum mass, moment of inertia and compactness of relativistic stars
Breu, Cosima
2016-01-01
A number of recent works have highlighted that it is possible to express the properties of general-relativistic stellar equilibrium configurations in terms of functions that do not depend on the specific equation of state employed to describe matter at nuclear densities. These functions are normally referred to as "universal relations" and have been found to apply, within limits, both to static or stationary isolated stars, as well as to fully dynamical and merging binary systems. Further extending the idea that universal relations can be valid also away from stability, we show that a universal relation is exhibited also by equilibrium solutions that are not stable. In particular, the mass of rotating configurations on the turning-point line shows a universal behaviour when expressed in terms of the normalised Keplerian angular momentum. In turn, this allows us to compute the maximum mass allowed by uniform rotation, M_{max}, simply in terms of the maximum mass of the nonrotating configuration, M_{TOV}, findi...
Jensen, Tue Vissing; Sørensen, Allan Hvidkjær
2013-01-01
A charged particle emits bremsstrahlung while traversing matter. We calculate the radiation cross section for bare heavy ions penetrating amorphous materials and single crystals at highly relativistic energies. The main component originates in scattering of the virtual photons of screened target...... at a very low value. Incoherent interaction with single target electrons gives rise to two additional bremsstrahlung components, a modest component due to scattering of virtual photons of the electrons on the projectile and a strong low-energy component due to scattering of the virtual photons...... of the projectile on the electrons. The difference in radiation levels can be traced to the mass of the scatterer. Since target electrons are more widely distributed than nuclei in a crystal channel the variation of the electron component of the bremsstrahlung with incidence angle to a major crystallographic...
Enhanced relativistic-electron-beam energy loss in warm dense aluminum.
Vaisseau, X; Debayle, A; Honrubia, J J; Hulin, S; Morace, A; Nicolaï, Ph; Sawada, H; Vauzour, B; Batani, D; Beg, F N; Davies, J R; Fedosejevs, R; Gray, R J; Kemp, G E; Kerr, S; Li, K; Link, A; McKenna, P; McLean, H S; Mo, M; Patel, P K; Park, J; Peebles, J; Rhee, Y J; Sorokovikova, A; Tikhonchuk, V T; Volpe, L; Wei, M; Santos, J J
2015-03-01
Energy loss in the transport of a beam of relativistic electrons in warm dense aluminum is measured in the regime of ultrahigh electron beam current density over 2×10^{11} A/cm^{2} (time averaged). The samples are heated by shock compression. Comparing to undriven cold solid targets, the roles of the different initial resistivity and of the transient resistivity (upon target heating during electron transport) are directly observable in the experimental data, and are reproduced by a comprehensive set of simulations describing the hydrodynamics of the shock compression and electron beam generation and transport. We measured a 19% increase in electron resistive energy loss in warm dense compared to cold solid samples of identical areal mass.
Relativistic surfatron process for Landau resonant electrons in radiation belts
Osmane, A
2014-01-01
Recent theoretical studies of the nonlinear wave-particle interactions for relativistic particles have shown that Landau resonant orbits could be efficiently accelerated along the mean background magnetic field for propagation angles $\\theta$ in close proximity to a critical propagation $\\theta_\\textrm{c}$ associated with a Hopf--Hopf bifurcation condition. In this report, we extend previous studies to reach greater modeling capacities for the study of electrons in radiation belts by including longitudinal wave effects and inhomogeneous magnetic fields. We find that even though both effects can limit the surfatron acceleration of electrons in radiation belts, gains in energy of the order of 100 keV, taking place on the order of ten milliseconds, are sufficiently strong for the mechanism to be relevant to radiation belt dynamics.
Melzani, Mickaël; Folini, Doris; Winisdoerffer, Christophe; Favre, Jean M
2014-01-01
Magnetic reconnection is a leading mechanism for magnetic energy conversion and high-energy non-thermal particle production in a variety of high-energy astrophysical objects, including ones with relativistic ion-electron plasmas (e.g., microquasars or AGNs) - a regime where first principle studies are scarce. We present 2D particle-in-cell (PIC) simulations of low $\\beta$ ion-electron plasmas under relativistic conditions, i.e., with inflow magnetic energy exceeding the plasma rest-mass energy. We identify outstanding properties: (i) For relativistic inflow magnetizations (here $10 80$), the reconnection electric field is sustained more by bulk inertia than by thermal inertia. It challenges the thermal-inertia-paradigm and its implications. (iii) The inflows feature sharp transitions at the entrance of the diffusion zones. These are not shocks but results from particle ballistic motions, all bouncing at the same location, provided that the thermal velocity in the inflow is far smaller than the inflow E cross...
Relativistic electron avalanches as a thunderstorm discharge competing with lightning.
Kelley, Nicole A; Smith, David M; Dwyer, Joseph R; Splitt, Michael; Lazarus, Steven; Martinez-McKinney, Forest; Hazelton, Bryna; Grefenstette, Brian; Lowell, Alexander; Rassoul, Hamid K
2015-08-12
Gamma-ray 'glows' are long duration (seconds to tens of minutes) X-ray and gamma-ray emission coming from thunderclouds. Measurements suggest the presence of relativistic runaway electron avalanches (RREA), the same process underlying terrestrial gamma-ray flashes. Here we demonstrate that glows are relatively a common phenomena near the tops of thunderstorms, when compared with events such as terrestrial gamma-ray flashes. Examining the strongest glow measured by the airborne detector for energetic emissions, we show that this glow is measured near the end of a downward RREA, consistent with occurring between the upper positive charge layer and the negative screening layer above it. The glow discharges the upper positive layer by ≥9.6 mA, strong enough to be an important charging mechanism of the storm. For this glow, the gamma-ray flux observed is close to the value at which relativistic feedback processes become important, with an avalanche multiplication factor of 4,500.
Trembling motion of relativistic electrons in a magnetic field
Rusin, Tomasz M
2010-01-01
One-electron 3+1 and 2+1 Dirac equations are used to calculate the motion of a relativistic electron in a vacuum in the presence of an external magnetic field. First, calculations are carried on an operator level and exact analytical results are obtained for the electron trajectories which contain both intraband frequency components, identified as the cyclotron motion, as well as interband frequency components, identified as the trembling motion (Zitterbewegung, ZB). Next, time-dependent Heisenberg operators are used for the same problem to compute average values of electron position and velocity employing Gaussian wave packets. It is shown that the presence of a magnetic field and the resulting quantization of the energy spectrum has pronounced effects on the electron Zitterbewegung: it introduces intraband frequency components into the motion, influences all the frequencies and makes the motion stationary (not decaying in time) in case of the 2+1 Dirac equation. Finally, simulations of the 2+1 Dirac equatio...
Clarifying the covariant formalism for the SZ effect due to relativistic non-thermal electrons
Boehm, Celine
2008-01-01
We derive the covariant formalism associated with the relativistic Sunyaev-Zel'dovich effect due to a non-thermal population of high energy electrons in clusters of galaxies. More precisely, we show that the formalism proposed by Wright in 1979, based on an empirical approach (but widely used in the literature) to compute the inverse Compton scattering of a population of relativistic electrons on CMB photons, can actually be re-interpreted as a Boltzmann-like equation, in the single scattering approximation. Although this would tend to reconcile Wright's approach with the latest works on the relativistic corrections of the thermal SZ effect, we find that the squared matrix amplitude derived by Wright by applying a relativistic Lorentz boost on Chandrasekhar's non-relativistic formula is incorrect (it is not equivalent to the well-known Compton scattering squared matrix amplitude in the limit of relativistic incoming electrons and low energy photons). This has important consequences. In particular, this modifi...
Kurita, Satoshi; Miyoshi, Yoshizumi; Blake, J. Bernard; Reeves, Geoffery D.; Kletzing, Craig A.
2016-04-01
It has been suggested that whistler mode chorus is responsible for both acceleration of MeV electrons and relativistic electron microbursts through resonant wave-particle interactions. Relativistic electron microbursts have been considered as an important loss mechanism of radiation belt electrons. Here we report on the observations of relativistic electron microbursts and flux variations of trapped MeV electrons during the 8-9 October 2012 storm, using the SAMPEX and Van Allen Probes satellites. Observations by the satellites show that relativistic electron microbursts correlate well with the rapid enhancement of trapped MeV electron fluxes by chorus wave-particle interactions, indicating that acceleration by chorus is much more efficient than losses by microbursts during the storm. It is also revealed that the strong chorus wave activity without relativistic electron microbursts does not lead to significant flux variations of relativistic electrons. Thus, effective acceleration of relativistic electrons is caused by chorus that can cause relativistic electron microbursts.
Whistler wave generation by non-gyrotropic, relativistic, electron beams
Skender, Marina
2014-01-01
Particle-in-cell code, EPOCH, is used for studying features of the wave component evident to propagate backwards from the front of the non-gyrotropic, relativistic beam of electrons injected in the Maxwellian, magnetised background plasma with decreasing density profile. According to recent findings presented in Tsiklauri (2011), Schmitz & Tsiklauri (2013) and Pechhacker & Tsiklauri (2012), in a 1.5-dimensional magnetised plasma system, the non-gyrotropic beam generates freely escaping electromagnetic radiation with properties similar to the Type-III solar radio bursts. In this study the backwards propagating wave component evident in the perpendicular components of the elecromagnetic field in such a system is presented for the first time. Background magnetic field strength in the system is varied in order to prove that the backwards propagating wave's frequency, prescribed by the whistler wave dispersion relation, is proportional to the specified magnetic field. Moreover, the identified whistlers are...
Energy deposition of quasi-two temperature relativistic electrons in fast-shock ignition scenario
Ghasemi, Seyed Abolfazl; Farahbod, Amir Hossein
2016-10-01
Previous calculations from Solodov et al. (2008) indicate that classical stopping and scattering dominate electrons energy deposition and transport when the electrons reach the dense plasma in FSI inertial confinement fusion concept [1]. Our calculations show that, by using quasi- two temperature electrons energy distribution function [2] in comparison with exponential [3] or monoenergetic distribution function and also increasing fast electrons energy to about 7 MeV, the ratio of beam blooming to straggling definitely decreases. Our analytical analysis shows that for fuel mass more than 1 mg and for fast ignitor wavelength λif > 0.53 μ m, straggling and beam blooming increases. Meanwhile, by reducing fast ignitor wavelength from 0.53 to 0.35 micron, and for fuel mass about 2 mg, electron penetration into the dense fuel slightly increases. Therefore, reduction of scattering (blooming and straggling) of electrons and enhancement of electron penetration into the dense fuel, can be obtained in relativistic regime with high energy fast electrons of the order of 5 Mev and more. Such derivations can be used in theoretical studies of the ignition conditions and PIC simulations of the electron transport in fast ignition scenario.
Relativistic effects on the modulational instability of electron plasma waves in quantum plasma
Basudev Ghosh; Swarniv Chandra; Sailendra Nath Paul
2012-05-01
Relativistic effects on the linear and nonlinear properties of electron plasma waves are investigated using the one-dimensional quantum hydrodynamic (QHD) model for a twocomponent electron–ion dense quantum plasma. Using standard perturbation technique, a nonlinear Schrödinger equation (NLSE) containing both relativistic and quantum effects has been derived. This equation has been used to discuss the modulational instability of the wave. Through numerical calculations it is shown that relativistic effects signiﬁcantly change the linear dispersion character of the wave. Unlike quantum effects, relativistic effects are shown to reduce the instability growth rate of electron plasma waves.
A reduced model for relativistic electron beam transport in solids and dense plasmas
Touati, M.; Feugeas, J.-L.; Nicolaï, Ph; Santos, J. J.; Gremillet, L.; Tikhonchuk, V. T.
2014-07-01
A hybrid reduced model for relativistic electron beam transport based on the angular moments of the relativistic kinetic equation with a special closure is presented. It takes into account collective effects with the self-generated electromagnetic fields as well as collisional effects with the slowing down of the relativistic electrons by plasmons, bound and free electrons and their angular scattering on both ions and electrons. This model allows for fast computations of relativistic electron beam transport while describing their energy distribution evolution. Despite the loss of information concerning the angular distribution of the electron beam, the model reproduces analytical estimates in the academic case of a monodirectional and monoenergetic electron beam propagating through a warm and dense plasma and hybrid particle-in-cell simulation results in a realistic laser-generated electron beam transport case.
Adapting High Brightness Relativistic Electron Beams for Ultrafast Science
Scoby, Cheyne Matthew
blow-out regime.” When the beam charge is maintained low, ultrashort electron bunches can be obtained enabling novel applications such as single shot Femtosecond Relativistic Electron Diffraction (FRED). High precision temporal diagnostic and synchronization techniques are integral to the use of femtosecond electron bunches for ultrafast science. An x-band rf streak camera provides measurements of the longitudinal profiles of sub-ps electron bunches. Spatial encoded electro-optic timestamping is developed to overcome the inherent rf-laser synchronization errors in rf photoinjectors. The ultrafast electron beams generated with the RF photoenjector are employed in pump-probe experiments wherein a target is illuminated with an intense pump laser to induce a transient behavior in the sample. FRED is used to study the melting of gold after heating with an intense femtosecond laser pulse. In a first experiment we study the process by taking different single-shot diffraction patterns at varying delays between the pump an probe beams. In a second experiment a variation of the technique is employed using the rf streak camera to time-stretch the beam after it has diffraction from the sample in order to capture the full melting dynamics in a single shot. Finally, relativistic ultrashort electron bunches are used as a probe of plasma dynamics in electron radiography/shadowgraphy experiments. This technique is used to study photoemission with intense laser pulses and the evolution of electromagnetic fields in a photoinduced dense plasma. This experiment is also performed in two different modes: one where different pictures are acquired at different time delays, and the other where a single streak image is used to obtain visualization of the propagation electromagnetic fields with an unprecedented 35 femtosecond resolution.
Wave-induced loss of ultra-relativistic electrons in the Van Allen radiation belts
Shprits, Yuri Y.; Drozdov, Alexander Y.; Spasojevic, Maria; Kellerman, Adam C.; Usanova, Maria E.; Engebretson, Mark J.; Agapitov, Oleksiy V.; Zhelavskaya, Irina S.; Raita, Tero J.; Spence, Harlan E.; Baker, Daniel N.; Zhu, Hui; Aseev, Nikita A.
2016-01-01
The dipole configuration of the Earth's magnetic field allows for the trapping of highly energetic particles, which form the radiation belts. Although significant advances have been made in understanding the acceleration mechanisms in the radiation belts, the loss processes remain poorly understood. Unique observations on 17 January 2013 provide detailed information throughout the belts on the energy spectrum and pitch angle (angle between the velocity of a particle and the magnetic field) distribution of electrons up to ultra-relativistic energies. Here we show that although relativistic electrons are enhanced, ultra-relativistic electrons become depleted and distributions of particles show very clear telltale signatures of electromagnetic ion cyclotron wave-induced loss. Comparisons between observations and modelling of the evolution of the electron flux and pitch angle show that electromagnetic ion cyclotron waves provide the dominant loss mechanism at ultra-relativistic energies and produce a profound dropout of the ultra-relativistic radiation belt fluxes. PMID:27678050
Wave-induced loss of ultra-relativistic electrons in the Van Allen radiation belts.
Shprits, Yuri Y; Drozdov, Alexander Y; Spasojevic, Maria; Kellerman, Adam C; Usanova, Maria E; Engebretson, Mark J; Agapitov, Oleksiy V; Zhelavskaya, Irina S; Raita, Tero J; Spence, Harlan E; Baker, Daniel N; Zhu, Hui; Aseev, Nikita A
2016-09-28
The dipole configuration of the Earth's magnetic field allows for the trapping of highly energetic particles, which form the radiation belts. Although significant advances have been made in understanding the acceleration mechanisms in the radiation belts, the loss processes remain poorly understood. Unique observations on 17 January 2013 provide detailed information throughout the belts on the energy spectrum and pitch angle (angle between the velocity of a particle and the magnetic field) distribution of electrons up to ultra-relativistic energies. Here we show that although relativistic electrons are enhanced, ultra-relativistic electrons become depleted and distributions of particles show very clear telltale signatures of electromagnetic ion cyclotron wave-induced loss. Comparisons between observations and modelling of the evolution of the electron flux and pitch angle show that electromagnetic ion cyclotron waves provide the dominant loss mechanism at ultra-relativistic energies and produce a profound dropout of the ultra-relativistic radiation belt fluxes.
Wave-induced loss of ultra-relativistic electrons in the Van Allen radiation belts
Shprits, Yuri Y.; Drozdov, Alexander Y.; Spasojevic, Maria; Kellerman, Adam C.; Usanova, Maria E.; Engebretson, Mark J.; Agapitov, Oleksiy V.; Zhelavskaya, Irina S.; Raita, Tero J.; Spence, Harlan E.; Baker, Daniel N.; Zhu, Hui; Aseev, Nikita A.
2016-09-01
The dipole configuration of the Earth's magnetic field allows for the trapping of highly energetic particles, which form the radiation belts. Although significant advances have been made in understanding the acceleration mechanisms in the radiation belts, the loss processes remain poorly understood. Unique observations on 17 January 2013 provide detailed information throughout the belts on the energy spectrum and pitch angle (angle between the velocity of a particle and the magnetic field) distribution of electrons up to ultra-relativistic energies. Here we show that although relativistic electrons are enhanced, ultra-relativistic electrons become depleted and distributions of particles show very clear telltale signatures of electromagnetic ion cyclotron wave-induced loss. Comparisons between observations and modelling of the evolution of the electron flux and pitch angle show that electromagnetic ion cyclotron waves provide the dominant loss mechanism at ultra-relativistic energies and produce a profound dropout of the ultra-relativistic radiation belt fluxes.
Equation of state of the relativistic free electron gas at arbitrary degeneracy
Faussurier, Gérald
2016-12-01
We study the problem of the relativistic free electron gas at arbitrary degeneracy. The specific heat at constant volume and particle number CV and the specific heat at constant pressure and particle number CP are calculated. The question of equation of state is also studied. Non degenerate and degenerate limits are considered. We generalize the formulas obtained in the non-relativistic and ultra-relativistic regimes.
Precipitation of relativistic electrons of the Van Allen belts into the proton aurora
Jordanova, Vania K [Los Alamos National Laboratory; Miyoshi, Y [NAGOYA UNIV; Sakaguchi, K [NAGOYA UNIV; Shiokawa, K [NAGOYA UNIV; Evans, D S [SEC/NOAA; Albert, Jay [AFRL; Connors, M [UNIV OF ATHABASCA
2008-01-01
The Van Allen electron belts consist of two regions encircling the earth in which relativistic electrons are trapped in the earth's magnetic field. Populations of relativistic electrons in the Van Allen belts vary greatly with geomagnetic disturbance and they are a major source of damage to space vehicles. In order to know when and by how much these populations of relativistic electrons increase, it is important to elucidate not only the cause of acceleration of relativistic electrons but also the cause of their loss from the Van Allen belts. Here we show the first evidence that left-hand polarized electromagnetic ion cyclotron (EMIC) plasma waves can cause the loss of relativistic electrons into the atmosphere, on the basis of results of an excellent set of ground and satellite observations showing coincident precipitation of ions with energies of tens of keV and of relativistic electrons into an isolated proton aurora. The proton aurora was produced by precipitation of ions with energies of tens of keV due to EMIC waves near the plasma pause, which is a manifestation of wave-particle interactions. These observations clarify that ions with energies of tens of keV affect the evolution of relativistic electrons in the Van Allen belts via parasitic resonance with EMIC waves, an effect that was first theoretically predicted in the early 1970's.
Confirmation of EMIC wave-driven relativistic electron precipitation
Hendry, Aaron T.; Rodger, Craig J.; Clilverd, Mark A.; Engebretson, Mark J.; Mann, Ian R.; Lessard, Marc R.; Raita, Tero; Milling, David K.
2016-06-01
Electromagnetic ion cyclotron (EMIC) waves are believed to be an important source of pitch angle scattering driven relativistic electron loss from the radiation belts. To date, investigations of this precipitation have been largely theoretical in nature, limited to calculations of precipitation characteristics based on wave observations and small-scale studies. Large-scale investigation of EMIC wave-driven electron precipitation has been hindered by a lack of combined wave and precipitation measurements. Analysis of electron flux data from the POES (Polar Orbiting Environmental Satellites) spacecraft has been suggested as a means of investigating EMIC wave-driven electron precipitation characteristics, using a precipitation signature particular to EMIC waves. Until now the lack of supporting wave measurements for these POES-detected precipitation events has resulted in uncertainty regarding the driver of the precipitation. In this paper we complete a statistical study comparing POES precipitation measurements with wave data from several ground-based search coil magnetometers; we further present a case study examining the global nature of this precipitation. We show that a significant proportion of the precipitation events correspond with EMIC wave detections on the ground; for precipitation events that occur directly over the magnetometers, this detection rate can be as high as 90%. Our results demonstrate that the precipitation region is often stationary in magnetic local time, narrow in L, and close to the expected plasmapause position. Predominantly, the precipitation is associated with helium band rising tone Pc1 waves on the ground. The success of this study proves the viability of POES precipitation data for investigating EMIC wave-driven electron precipitation.
Mei Symmetry and Lie Symmetry of the Rotational Relativistic Variable Mass System
FANGJian-Hui
2003-01-01
The Mei symmetry and the Lie symmetry of a rotational relativistic variable mass system are studied. The definitions and criteria of the Mei symmetry and the Lie symmetry of the rotational relativistic variable mass system are given. The relation between the Mei symmetry and the Lie symmetry is found. The conserved quantities which the Mei symmetry and the Lie symmetry lead to are obtained. An example is given to illustrate the application of the result.
Ion-Acoustic Envelope Modes in a Degenerate Relativistic Electron-Ion Plasma
McKerr, M; Kourakis, I
2016-01-01
A self-consistent relativistic two-fluid model is proposed for one-dimensional electron-ion plasma dynamics. A multiple scales perturbation technique is employed, leading to an evolution equation for the wave envelope, in the form of a nonlinear Schr\\"odinger type equation (NLSE). The inclusion of relativistic effects is shown to introduce density-dependent factors, not present in the non-relativistic case - in the conditions for modulational instability. The role of relativistic effects on the linear dispersion laws and on envelope soliton solutions of the NLSE is discussed.
A relativistic model of electron cyclotron current drive efficiency in tokamak plasmas
Lin-Liu Y.R.; Hu Y.J.; Hu Y.M.
2012-01-01
A fully relativistic model of electron cyclotron current drive (ECCD) efficiency based on the adjoint function techniques is considered. Numerical calculations of the current drive efficiency in a tokamak by using the variational approach are performed. A fully relativistic extension of the variational principle with the modified basis functions for the Spitzer function with momentum conservation in the electron-electron collision is described in general tokamak geometry. The model developed ...
Naumenko, G. A.; Shevelev, M. V.; Popov, Yu A.
2016-08-01
During the interaction of the relativistic electrons field with a dielectric target various types of electromagnetic radiation, such as Cerenkov radiation, diffraction radiation, transition radiation can be generated. In this report we present the results of experimental studies of the diffraction radiation generated by relativistic electrons in a dielectric target at the interface vacuum-insulator and insulator-conductor in the millimeter wavelength range. The experimental results show that the component of the diffraction radiation of relativistic electrons at the interface insulator-conductor, for any significant refractive index of insulator, is suppressed. The analysis of the results from different points of view was done.
K-shell (e, 3e) double ionization of beryllium by relativistic electrons
Becher, M; Joulakian, B [Universite Paul Verlaine-Metz, Laboratoire de Physique Moleculaire et des Collisions, Member FR CNRS 2843 Jean Barriol 1 Bd Arago, 57078 Metz Cedex 3 (France)
2009-03-28
The (e, 3e) process, producing hollow metastable Be{sup 2+}(2s{sup 2}) by very energetic electrons (>100 keV), is studied by using a relativistic procedure based on the application of the first term of the Born series for the determination of the corresponding fully differential cross section. The very fast projectile electron, impinging on the K shell of the neutral beryllium, is described by Dirac plane-wave solutions with the appropriate wave vectors. All atomic electrons and the two final-state-bound electrons are taken into account by non-relativistic Jastrow-type correlated functions. The two slow ejected electrons in the continuum are described by the fully correlated three-Coulomb (3C) function. The comparison of the results with those obtained by our recent non-relativistic approach shows the necessity of the introduction of the relativistic treatment.
Observation of relativistic runaway electrons by synchrotron radiation in TEXTOR
Jaspers, R.; Lopes Cardozo, N.J.; Schueller, F.C. (FOM-Instituut voor Plasmafysica, Rijnhuizen (Netherlands)); Finken, K.H.; Mank, G.; Rusbueldt, D.; Hoenen, F. (Forschungszentrum Juelich GmbH (Germany). Inst. fuer Plasmaphysik); Boedo, J. (California Univ., Los Angeles, CA (United States). Inst. of Plasma and Fusion Research)
1992-01-01
Runaway electrons are a promising tool to study magnetic turbulence in tokamak plasma. Recently, several studies have been devoted to this issue. In these studies hard X-rays, created when runaways hit the limiter, have been analysed. This paper also addresses the question of confinement of runaways. Here, however, not the runaways leaving the plasma are studied, but the runaways in the interior. They were diagnosed by means of the infrared synchrotron radiation which relativistic runaways (> 10 MeV) emit, as shown by Finken et al. With this tool information can be obtained about runaway - confinement times, energy, birth-rate, dimensions of the runaway beam and perhaps about their energy distribution. In this paper, at first a presentation of the measurements is given and the energy and pitch angle is deduced from the data. Then a comparison of the runaway confinement in low density plasmas (n[sub e](0) < 0.8 10[sup 19] m[sup -3]) is made for three different conditions; normal ohmic discharge, discharge with a gas puff and one with neutral beam injection (NBI). (author) 7 refs., 4 figs.
Cooling of relativistic electron beams in chirped laser pulses
Yoffe, Samuel R; Kravets, Yevgen; Jaroszynski, Dino A
2015-01-01
The next few years will see next-generation high-power laser facilities (such as the Extreme Light Infrastructure) become operational, for which it is important to understand how interaction with intense laser pulses affects the bulk properties of a relativistic electron beam. At such high field intensities, we expect both radiation reaction and quantum effects to play a significant role in the beam dynamics. The resulting reduction in relative energy spread (beam cooling) at the expense of mean beam energy predicted by classical theories of radiation reaction depends only on the energy of the laser pulse. Quantum effects suppress this cooling, with the dynamics additionally sensitive to the distribution of energy within the pulse. Since chirps occur in both the production of high-intensity pulses (CPA) and the propagation of pulses in media, the effect of using chirps to modify the pulse shape has been investigated using a semi-classical extension to the Landau--Lifshitz theory. Results indicate that even la...
Effective photon mass and exact translating quantum relativistic structures
Haas, Fernando; Manrique, Marcos Antonio Albarracin
2016-04-01
Using a variation of the celebrated Volkov solution, the Klein-Gordon equation for a charged particle is reduced to a set of ordinary differential equations, exactly solvable in specific cases. The new quantum relativistic structures can reveal a localization in the radial direction perpendicular to the wave packet propagation, thanks to a non-vanishing scalar potential. The external electromagnetic field, the particle current density, and the charge density are determined. The stability analysis of the solutions is performed by means of numerical simulations. The results are useful for the description of a charged quantum test particle in the relativistic regime, provided spin effects are not decisive.
Electron and Ion Acceleration in Relativistic Shocks with Applications to GRB Afterglows
Warren, Donald C; Bykov, Andrei M; Lee, Shiu-Hang
2015-01-01
We have modeled the simultaneous first-order Fermi shock acceleration of protons, electrons, and helium nuclei by relativistic shocks. By parameterizing the particle diffusion, our steady-state Monte Carlo simulation allows us to follow particles from particle injection at nonthermal thermal energies to above PeV energies, including the nonlinear smoothing of the shock structure due to cosmic-ray (CR) backpressure. We observe the mass-to-charge (A/Z) enhancement effect believed to occur in efficient Fermi acceleration in non-relativistic shocks and we parameterize the transfer of ion energy to electrons seen in particle-in-cell (PIC) simulations. For a given set of environmental and model parameters, the Monte Carlo simulation determines the absolute normalization of the particle distributions and the resulting synchrotron, inverse-Compton, and pion-decay emission in a largely self-consistent manner. The simulation is flexible and can be readily used with a wide range of parameters typical of gamma-ray burst ...
Arpita Ghosh; Somenath Chakrabarty
2011-09-01
Following an extremely interesting idea (Schieber 1984), published long ago, the work function associated with the emission of ultra-relativistic electrons from magnetically deformed metallic crystal (mainly iron) at the outer crust of a magnetar is obtained using relativistic version of Thomas–Fermi type model for electron distribution around the nuclei in this region. In the present scenario, surprisingly, the work function becomes anisotropic; the longitudinal part is an increasing function of magnetic field strength, whereas the transverse part diverges.
SPECTRAL VARIABILITY AND TRANSIENT INJECTION OF RELATIVISTIC ELECTRONS FOR BL LAC OBJECTS
MEI DONG-CHENG; XIE GUANG-ZHONG; CHEN LUO-EN
2000-01-01
The spectral hardening with increasing intensity in optical range for four BL Lac objects have been found by analyzing our observed data. Making use of the synchrotron loss of transient injection of relativistic electrons, we succeeded in explaining the phenomenon of the spectral hardening in the outburst phase. The value of magnetic intensity and the limit condition of the transient injection of relativistic electrons seem to be reasonable.
Mei Symmetry and Lie Symmetry of the Rotational Relativistic Variable Mass System
FANG Jian-Hui
2003-01-01
The Mei symmetry and the Lie symmetry of a rotational relativistic variable masssystem are studied. Thedefinitions and criteria of the Mei symmetry and the Lie symmetry of the rotational relativistic variable mass system aregiven. The relation between the Mei symmetry and the Lie symmetry is found. The conserved quantities which the Meisymmetry and the Lie symmetry lead to are obtained. An example is given to illustrate the application of the result.
Whistler wave generation by non-gyrotropic, relativistic, electron beams
Skender, Marina; Tsiklauri, David
2014-05-01
]. In this study [5], for the first time, the backwards propagating wave component evident in the perpendicular components of the electromagnetic field in such a system is presented. Features of the wave component propagating backwards from the front of the non-gyrotropic, relativistic, beam of electrons injected in the Maxwellian, magnetised background plasma with decreasing density profile are studied by using the Particle-In-Cell code EPOCH. Magnetic field in the 1.5-dimensional system is varied in order to prove that the backwards propagating wave is harmonic of the electron cyclotron frequency. The analysis has lead to the identification of the backwards travelling waves as whistlers. Moreover, the whistlers are shown to be generated by the normal and anomalous Doppler resonance. Large fraction of the energy of the perpendicular electromagnetic field components is found to be carried away by the whistler waves. [1] D. Tsiklauri, Phys. Plasmas 18, 052903 (2011). [2] D. Tsiklauri, H. Schmitz, Geophys. Res. Abs. 15, EGU2013-5403 (2013). [3] H. Schmitz, D. Tsiklauri, Phys. Plasmas 20, 062903 (2013). [4] R. Pechhacker, D. Tsiklauri, Phys. Plasmas 19, 112903 (2012). [5] M. Skender, D. Tsiklauri, submitted to Phys. Plasmas (2013): http://astro.qmul.ac.uk/ tsiklauri/
Sahai, Aakash A
2014-01-01
We analyze the motion of the plasma critical layer by two different processes in the relativistic-electron laser-plasma interaction regime ($a_0>1$). The differences are highlighted when the critical layer ions are stationary in contrast to when they move with it. Controlling the speed of the plasma critical layer in this regime is essential for creating low-$\\beta$ traveling acceleration structures of sufficient laser-excited potential for laser ion accelerators (LIA). In Relativistically Induced Transparency Acceleration (RITA) scheme the heavy plasma-ions are fixed and only trace-density light-ions are accelerated. The relativistic critical layer and the acceleration structure move longitudinally forward by laser inducing transparency through apparent relativistic increase in electron mass. In the Radiation Pressure Acceleration (RPA) scheme the whole plasma is longitudinally pushed forward under the action of the laser radiation pressure, possible only when plasma ions co-propagate with the laser front. I...
Correction of Relativistic Center-of-Mass Vector on Electric Polarizability of Pion Meson
DONG Yu-Bing
2005-01-01
We estimate the correction of relativistic center-of-mass vector on electric polarizability of an equal-mass quark-antiquark system numerically. Effect on the system confined by different interactive potentials is analysed. A great improvement for the electric polarizability of pion meson is obtained.
Physical stress, mass, and energy for non-relativistic spinful matter
Geracie, Michael; Roberts, Matthew M
2016-01-01
For theories of relativistic matter fields with spin there exist two possible definitions of the stress-energy tensor, one defined by a variation of the action with the coframes at fixed connection, and the other at fixed torsion. These two stress-energy tensors do not necessarily coincide and it is the latter that corresponds to the Cauchy stress measured in the lab. In this note we discuss the corresponding issue for non-relativistic matter theories. We point out that while the physical non-relativistic stress, momentum, and mass currents are defined by a variation of the action at fixed torsion, the energy current does not admit such a description and is naturally defined at fixed connection. Any attempt to define an energy current at fixed torsion results in an ambiguity which cannot be resolved from the background spacetime data or conservation laws. We also provide computations of these quantities for some simple non-relativistic actions.
Cheung, C.C.Teddy; Stawarz, L.; Harris, D.E.; Ostrowski, M.
2007-10-15
We report new detections of the hotspots in Cygnus A at 4.5 and 8.0 microns with the Spitzer Space Telescope. Together with detailed published radio observations and synchrotron self-Compton modeling of previous X-ray detections, we reconstruct the underlying electron energy spectra of the two brightest hotspots (A and D). The low-energy portion of the electron distributions have flat power-law slopes (s {approx} 1.5) up to the break energy which corresponds almost exactly to the mass ratio between protons and electrons; we argue that these features are most likely intrinsic rather than due to absorption effects. Beyond the break, the electron spectra continue to higher energies with very steep slopes s>3. Thus, there is no evidence for the 'canonical' s=2 slope expected in 1st order Fermi-type shocks within the whole observable electron energy range. We discuss the significance of these observations and the insight offered into high-energy particle acceleration processes in mildly relativistic shocks.
Study of the Lie symmetries of a relativistic variable mass system
方建会
2002-01-01
The differential equations of motion of a relativistic variable mass system are given. By using the invariance of the differential equations under the infinitesimal transformations of groups, the determining equations and the restriction equations of the Lie symmetries of a relativistic variable mass system are built, and the structure equation and the conserved quantity of the Lie symmetries are obtained. Then the inverse problem of the Lie symmetries is studied. The corresponding Lie symmetries are found according to a known conserved quantity. An example is given to illustrate the application of the result.
Quantum Geometry: Relativistic energy approach to cooperative electron-nucleary-transition spectrum
Ольга Юрьевна Хецелиус
2014-11-01
Full Text Available An advanced relativistic energy approach is presented and applied to calculating parameters of electron-nuclear 7-transition spectra of nucleus in the atom. The intensities of the spectral satellites are defined in the relativistic version of the energy approach (S-matrix formalism, and gauge-invariant quantum-electrodynamical perturbation theory with the Dirac-Kohn-Sham density-functional zeroth approximation.
SU Zhen-Peng; ZHENG Hui-Nan
2009-01-01
The bounce-averaged Fokker-Planck equation is solved to study the relativistic electron phase space density(PSD)evolution in the outer radiation belt due to resonant interactions with plasmaspheric plume electromagnetic ion cyclotron(EMIC)waves.It is found that the PSDs of relativistic electrons can be depleted by 1-3 orders of magnitude in 5h,supporting the previous finding that resonant interactions with EMIC waves may account for the frequently observed relativistic electron flux dropouts in the outer radiation belt during the main phase of a storm.The significant precipitation Joss of ～Me V electrons is primarily induced by the EMIC waves in H~+ and He~+ bands.The rapid remove of highly relativistic electrons(＞5 MeV)is mainly driven by the EMIC waves in O~+ band at lower pitch-angles,as well as the EMIC waves in H~+ and He~+ bands at larger pitch-angles.Moreover,a stronger depletion of relativistic electrons is found to occur over a wider pitch angle range when EMIC waves are centering relatively higher in the band.
A Parvazian
2010-12-01
Full Text Available Fast ignition is a new method for inertial confinement fusion (ICF in which the compression and ignition steps are separated. In the first stage, fuel is compressed by laser or ion beams. In the second phase, relativistic electrons are generated by pettawat laser in the fuel. Also, in the second phase 5-35 MeV protons can be generated in the fuel. Electrons or protons can penetrate in to the ultra-dense fuel and deposit their energy in the fuel . More recently, cylindrical rather than spherical fuel chambers with magnetic control in the plasma domain have been also considered. This is called magnetized target fusion (MTF. Magnetic field has effects on relativistic electrons energy deposition rate in fuel. In this work, fast ignition method in cylindrical fuel chambers is investigated and transportation of the relativistic electrons and protons is calculated using MCNPX and FLUKA codes with 0. 25 and 0. 5 tesla magnetic field in single and dual hot spot. Furthermore, the transfer rate of relativistic electrons and high energy protons to the fuel and fusion gain are calculated. The results show that the presence of external magnetic field guarantees higher fusion gain, and relativistic electrons are much more appropriate objects for ignition. MTF in dual hot spot can be considered as an appropriate substitution for the current ICF techniques.
Modeling of modified electron-acoustic solitary waves in a relativistic degenerate plasma
Hossen, M. R.; Mamun, A. A. [Jahangirnagar University, Savar, Dhaka (Bangladesh)
2014-12-15
The modeling of a theoretical and numerical study on the nonlinear propagation of modified electron-acoustic (mEA) solitary waves has been carried out in an unmagnetized, collisionless, relativistic, degenerate quantum plasma (containing non-relativistic degenerate inertial cold electrons, both non-relativistic and ultra-relativistic degenerate hot electron and inertial positron fluids, and positively-charged static ions). A reductive perturbation technique is used to derive the planar and the nonplanar Korteweg-de Vries (K-dV) equations, which admit a localized wave solution for the solitary profile. The solitary wave's characteristics are found to have been influenced significantly for the non-relativistic and the ultra-relativistic limits. The mEA solitary waves are also found to have been significantly modified due to the effects of the degenerate pressure and the number densities of this dense plasma's constituents. The properties of the planar K-dV solitary wave are quite different from those of the nonplanar K-dV solitary wave. The relevance of our results to astrophysical objects (like white dwarfs and neutron stars), which are of scientific interest, is briefly mentioned.
Kozyreva, O. V.; Pilipenko, V. A.; Engebretson, M. J.; Yumoto, K.
2004-05-01
A new ULF wave index, characterizing the turbulent level of the geomagnetic field, has been calculated and applied for the analysis of relativistic electron enhancements during Space Weather Month (10-30 September 1999). The wave index has been produced from the INTERMAGNET, MACCS and CPMN dense arrays of ULF magnetometers in the Northern hemisphere. During the analyzed period two magnetic storms occurred (on September 12 and 22), and several significant increases of relativistic electron flux at geostationary orbit (up to 2-3 orders of magnitude) were detected by geostationary monitors. However, these electron enhancements were not related to the magnetic storm intervals. Instead, and rather unexpectedly, they correlated well with intervals of elevated ULF wave index, caused by the occurrence of intense Pc5 pulsations in the magnetosphere. This comparison is an additional indication of the possible importance of magnetospheric turbulence in energizing relativistic electrons.
Duskside Relativistic Electron Precipitation in the SAMPEX data set from 1992-2004
Comess, M. D.; Smith, D. M.; Millan, R. M.; Sample, J. G.
2009-12-01
Evidence for duskside relativistic electron precipitation (DREP) within the Earth's outer radiation belt has been seen in several sets of high altitude balloon data (MAXIS, MINIS, INTERBOA). The DREP events have a characteristically short timescale. They are the hardest X-ray events seen from balloons with typical energy around 1MeV. They always occur in the evening hemisphere between 12-24 MLT. These events appear to be intense enough that they may represent the dominant loss mechanism in the outer electron belt for relativistic electrons. However, such evidence has rarely been seen in satellite data as DREP have been hard to distinguish from other forms of precipitation such as band precipitation and microbursts. Statistical evidence for duskside relativistic electron precipitations (DREP) is presented based on a survey of data collected by SAMPEX from 1992-2004. Correlations among event duration, intensity, spectral hardness and duskside MLT are observed in this sample.
Near realtime forecasting of MeV protons on the basis of sub relativistic electrons
Labrenz, Johannes; Heber, Bernd; Kuehl, Patrick; Sarlanis, Christos; Malandraki, Olga; Posner, Arik
2016-04-01
A major impact on human and robotic space exploration activities is the sudden and prompt occurrence of solar energetic ion events. In order to provide up to an hour warning before these particles arrive at Earth, relativistic electron and below 50 MeV proton data from the Electron Proton Helium Instrument (EPHIN) on SOHO were used to implement the 'Relativistic Electron Alert System for Exploration (REleASE)'. It has been demonstrated that the analysis of relativistic electron time profiles provides a low miss and false alarm rate. High Energy Solar Particle Events foRecastIng and Analysis (HESPERIA) is a project funded within the European Union's Horizon 2020 research and innovation programme (PROTEC-1-2014 Call: Space Weather). Within this project the REleASE forecasting scheme was rewritten in the open access programming language PYTHON and will be made public. As a next step, we have analyzed the possibility to also use, along with relativistic electrons (v > 0.9 c) provided by SOHO, near-relativistic (v forecasting scheme to provide reliable SEP forecasts. A comparison of measured and forecast proton intensities by SOHO/EPHIN and ACE/EPAM will be presented. In addition we investigated the false alarm rate and detection probability of solar ion events. This project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 637324.
Effect of EMIC Wave Normal Angle Distribution on Relativistic Electron Scattering
Gamayunov, K. V.; Khazanov, G. V.
2006-01-01
The flux level of outer-zone relativistic electrons (above 1 MeV) is extremely variable during geomagnetic storms, and controlled by a competition between acceleration and loss. Precipitation of these electrons due to resonant pitch-angle scattering by electromagnetic ion cyclotron (EMIC) waves is considered one of the major loss mechanisms. This mechanism was suggested in early theoretical studies more than three decades ago. However, direct experimental evidence of the wave role in relativistic electrons precipitation is difficult to obtain because of lack of concurrent measurements of precipitating electrons at low altitudes and the waves in a magnetically conjugate equatorial region. Recently, the data from balloon-borne X-ray instruments provided indirect but strong evidence on an efficiency of the EMIC wave induced loss for the outer-zone relativistic electrons. These observations stimulated theoretical studies that, particularly, demonstrated that EMIC wave induced pitch-angle diffusion of MeV electrons can operate in the strong diffusion limit and this mechanism can compete with relativistic electron depletion caused by the Dst effect during the initial and main phases of storm. Although an effectiveness of relativistic electron scattering by EMIC waves depends strongly on the wave spectral properties, the most favorable assumptions regarding wave characteristics has been made in all previous theoretical studies. Particularly, only quasi field-aligned EMIC waves have been considered as a driver for relativistic electron loss. At the same time, there is growing experimental and theoretical evidence that these waves can be highly oblique; EMIC wave energy can occupy not only the region of generation, i.e. the region of small wave normal angles, but also the entire wave normal angle region, and even only the region near 90 degrees. The latter can dramatically change he effectiveness of relativistic electron scattering by EMIC waves. In the present study, we
Luttikhof, M.J.H.; Khachatryan, A.G.; Goor, van F.A.; Boller, K.-J.
2009-01-01
In recent experiments ultra-relativistic femtosecond electron bunches were generated by a Laser Wakefield Accelerator (LWFA) in different regimes. Here we predict that even attosecond bunches can be generated by an LWFA due to the fast betatron phase mixing within a femtosecond electron bunch. The a
Compression-amplified EMIC waves and their effects on relativistic electrons
Li, L. Y., E-mail: lyli-ssri@buaa.edu.cn; Yu, J.; Cao, J. B. [School of Space and Environment, Beihang University, Beijing (China); Yuan, Z. G. [School of Electronic Information, Wuhan University, Wuhan (China)
2016-06-15
During enhancement of solar wind dynamic pressure, we observe the periodic emissions of electromagnetic ion cyclotron (EMIC) waves near the nightside geosynchronous orbit (6.6R{sub E}). In the hydrogen and helium bands, the different polarized EMIC waves have different influences on relativistic electrons (>0.8 MeV). The flux of relativistic electrons is relatively stable if there are only the linearly polarized EMIC waves, but their flux decreases if the left-hand polarized (L-mode) EMIC waves are sufficiently amplified (power spectral density (PSD) ≥ 1 nT{sup 2}/Hz). The larger-amplitude L-mode waves can cause more electron losses. In contrast, the R-mode EMIC waves are very weak (PSD < 1 nT{sup 2}/Hz) during the electron flux dropouts; thus, their influence may be ignored here. During the electron flux dropouts, the relativistic electron precipitation is observed by POES satellite near the foot point (∼850 km) of the wave emission region. The quasi-linear simulation of wave-particle interactions indicates that the L-mode EMIC waves can cause the rapid precipitation loss of relativistic electrons, especially when the initial resonant electrons have a butterfly-like pitch angle distribution.
A Short Review of Relativistic Iron Lines from Stellar-Mass Black Holes
Miller, J M
2006-01-01
In this contribution, I briefly review recent progress in detecting and measuring the properties of relativistic iron lines observed in stellar-mass black hole systems, and the aspects of these lines that are most relevant to studies of similar lines in Seyfert-1 AGN. In particular, the lines observed in stellar-mass black holes are not complicated by complex low-energy absorption or partial-covering of the central engine, and strong lines are largely independent of the model used to fit the underlying broad-band continuum flux. Indeed, relativistic iron lines are the most robust diagnostic of black hole spin that is presently available to observers, with specific advantages over the systematics-plagued disk continuum. If accretion onto stellar-mass black holes simply scales with mass, then the widespread nature of lines in stellar-mass black holes may indicate that lines should be common in Seyfert-1 AGN, though perhaps harder to detect.
Tachyonic quantum densities of relativistic electron plasmas: Cherenkov spectra of γ-ray pulsars
Tomaschitz, Roman, E-mail: tom@geminga.org
2014-06-27
Tachyonic Cherenkov radiation in second quantization can explain the subexponential spectral tails of GeV γ-ray pulsars (Crab pulsar, PSR J1836+5925, PSR J0007+7303, PSR J2021+4026) recently observed with the Fermi-LAT, VERITAS and MAGIC telescopes. The radiation is emitted by a thermal ultra-relativistic electron plasma. The Cherenkov effect is derived from a Maxwell–Proca field with negative mass-square in a dispersive spacetime. The frequency variation of the tachyon mass results in exp(−β{sup ^}ω{sup 1−ρ}) attenuation of the asymptotic Cherenkov energy flux, where β{sup ^} is a decay constant related to the electron temperature and ρ is the frequency scaling exponent of the tachyon mass. An exponent in the range 0<ρ<1 can reproduce the observed subexponential decay of the energy flux. For the Crab pulsar, we find ρ=0.81±0.02, inferred from the substantially weaker-than-exponential decay of its spectral tail measured by MAGIC over an extended energy range. The scaling exponent ρ determines whether the group velocity of the tachyonic γ-rays is sub- or superluminal. - Highlights: • Quantized tachyonic Cherenkov densities lead to subexponential spectral decay. • γ-Ray spectral fits to Crab pulsar, PSR J1836+5925, PSR J0007+7303, PSR J2021+4026. • The polarization of γ-rays is analyzed in the quasiclassical regime and quantum limit. • Three degrees of polarization due to the negative mass-square of the Maxwell–Proca field. • Weibull decay of spectral tails caused by frequency scaling of the tachyon mass.
Hafez, M. G.; Talukder, M. R.; Sakthivel, R.
2016-05-01
The theoretical and numerical studies have been investigated on nonlinear propagation of weakly relativistic ion acoustic solitary waves in an unmagnetized plasma system consisting of nonextensive electrons, positrons and relativistic thermal ions. To study the characteristics of nonlinear propagation of the three-component plasma system, the reductive perturbation technique has been applied to derive the Korteweg-de Vries equation, which divulges the soliton-like solitary wave solution. The ansatz method is employed to carry out the integration of this equation. The effects of nonextensive electrons, positrons and relativistic thermal ions on phase velocity, amplitude and width of soliton and electrostatic nonlinear propagation of weakly relativistic ion acoustic solitary waves have been discussed taking different plasma parameters into consideration. The obtained results can be useful in understanding the features of small amplitude localized relativistic ion acoustic solitary waves in an unmagnetized three-component plasma system for hard thermal photon production with relativistic heavy ions collision in quark-gluon plasma as well as for astrophysical plasmas.
Persistent current of relativistic electrons on a Dirac ring in presence of impurities
Ghosh, Sumit
2014-08-01
We study the behaviour of persistent current of relativistic electrons on a one dimensional ring in presence of attractive/repulsive scattering potentials. In particular, we investigate the persistent current in accordance with the strength as well as the number of the scattering potential. We find that in presence of single scatterer the persistent current becomes smaller in magnitude than the scattering free scenario. This behaviour is similar to the non-relativistic case. Even for a very strong scattering potential, finite amount of persistent current remains for a relativistic ring. In presence of multiple scatterer we observe that the persistent current is maximum when the scatterers are placed uniformly compared to the current averaged over random configurations. However if we increase the number of scatterers, we find that the random averaged current increases with the number of scatterers. The latter behaviour is in contrast to the non-relativistic case. © 2014 EDP Sciences, SIF, Springer-Verlag Berlin Heidelberg.
Irfan, M.; Ali, S.; Mirza, Arshad M.
2016-02-01
Two-fluid quantum magnetohydrodynamic (QMHD) equations are employed to investigate linear and nonlinear properties of the magnetosonic waves in a semi-relativistic dense plasma accounting for degenerate relativistic electrons. In the linear analysis, a plane wave solution is used to derive the dispersion relation of magnetosonic waves, which is significantly modified due to relativistic degenerate electrons. However, for a nonlinear investigation of solitary and shock waves, we employ the reductive perturbation technique for the derivation of Korteweg-de Vries (KdV) and Korteweg-de Vries Burger (KdVB) equations, admitting nonlinear wave solutions. Numerically, it is shown that the wave frequency decreases to attain a lowest possible value at a certain critical number density Nc(0), and then increases beyond Nc(0) as the plasma number density increases. Moreover, the relativistic electrons and associated pressure degeneracy lead to a reduction in the spatial extents of the magnetosonic waves and a strengthening of the shock amplitude. The results might be important for understanding the linear and nonlinear magnetosonic excitations in dense astrophysical plasmas, such as in white dwarfs, magnetars and neutron stars, etc., where relativistic degenerate electrons are present.
Light Fermion Finite Mass Effects in Non-relativistic Bound States
Eiras, D; Eiras, Dolors; Soto, Joan
2000-01-01
We present analytic expressions for the vacuum polarization effects due to a light fermion with finite mass in the binding energy and in the wave function at the origin of QED and (weak coupling) QCD non-relativistic bound states. Applications to exotic atoms, \\Upsilon (1s) and t\\bar{t} production near threshold are briefly discussed.
Ultra-low-frequency wave-driven diffusion of radiation belt relativistic electrons.
Su, Zhenpeng; Zhu, Hui; Xiao, Fuliang; Zong, Q-G; Zhou, X-Z; Zheng, Huinan; Wang, Yuming; Wang, Shui; Hao, Y-X; Gao, Zhonglei; He, Zhaoguo; Baker, D N; Spence, H E; Reeves, G D; Blake, J B; Wygant, J R
2015-12-22
Van Allen radiation belts are typically two zones of energetic particles encircling the Earth separated by the slot region. How the outer radiation belt electrons are accelerated to relativistic energies remains an unanswered question. Recent studies have presented compelling evidence for the local acceleration by very-low-frequency (VLF) chorus waves. However, there has been a competing theory to the local acceleration, radial diffusion by ultra-low-frequency (ULF) waves, whose importance has not yet been determined definitively. Here we report a unique radiation belt event with intense ULF waves but no detectable VLF chorus waves. Our results demonstrate that the ULF waves moved the inner edge of the outer radiation belt earthward 0.3 Earth radii and enhanced the relativistic electron fluxes by up to one order of magnitude near the slot region within about 10 h, providing strong evidence for the radial diffusion of radiation belt relativistic electrons.
Kersten, K.; Cattell, C. A.; Breneman, A.; Goetz, K.; Kellogg, P. J.; Wygant, J. R.; Wilson, L. B., III; Blake, J. B.; Looper, M. D.; Roth, I.
2011-01-01
We present multi-satellite observations of large amplitude radiation belt whistler-mode waves and relativistic electron precipitation. On separate occasions during the Wind petal orbits and STEREO phasing orbits, Wind and STEREO recorded intense whistler-mode waves in the outer nightside equatorial radiation belt with peak-to-peak amplitudes exceeding 300 mV/m. During these intervals of intense wave activity, SAMPEX recorded relativistic electron microbursts in near magnetic conjunction with Wind and STEREO. This evidence of microburst precipitation occurring at the same time and at nearly the same magnetic local time and L-shell with a bursty temporal structure similar to that of the observed large amplitude wave packets suggests a causal connection between the two phenomena. Simulation studies corroborate this idea, showing that nonlinear wave.particle interactions may result in rapid energization and scattering on timescales comparable to those of the impulsive relativistic electron precipitation.
Hafez, M. G.; Talukder, M. R.; Hossain Ali, M.
2016-01-01
The Korteweg-de Vries Burgers (KdVB) -like equation is derived to study the characteristics of nonlinear propagation of ion acoustic solitions in a highly relativistic plasma containing relativistic ions and nonextensive distribution of electrons and positrons using the well known reductive perturbation technique. The KdVB-like equation is solved employing the Bernoulli's equation method taking unperturbed positron to electron concentration ratio, electron to positron temperature ratio, strength of nonextensivity, ion kinematic viscosity, and highly relativistic streaming factor. It is found that these parameters significantly modify the structures of the solitonic excitation. The ion acoustic shock profiles are observed due to the influence of ion kinematic viscosity. In the absence of dissipative term to the KdVB equation, compressive and rarefactive solitons are observed in case of superthermality, but only compressive solitons are found for the case of subthermality.
Investigation of EMIC Waves During Balloon Detected Relativistic Electron Precipitation Events
Woodger, L. A.; Millan, R. M.
2009-12-01
Multiple relativistic electron precipitation (REP) events were detected by balloon-borne instrumentation during the MAXIS 2000 and MINIS 2005 campaigns. It has been suggested that resonance with EMIC waves caused these precipitation events (Lorentzen et al, 2000 and Millan et al, 2002) due to their location in the dusk sector. We present observations of dusk-side relativistic electron precipitation events, and use supporting satellite and theoretical data to investigate the relationship between EMIC waves and the detected REP. Satellite data can provide direct measurements of not only the waves themselves but also important resonance condition parameters. The data will be presented collectively with each event to showcase similarities and differences between events and the challenges that arise in trying to understand the relationship between dusk-side relativistic electron precipitation and EMIC waves.
Shukla, Chandrasekhar; Patel, Kartik
2016-01-01
We carry out Particle-in-Cell (PIC) simulations to study the instabilities associated with a 2-D sheared electron flow configuration against a neutralizing background of ions. Both weak and strong relativistic flow velocities are considered. In the weakly relativistic case, we observe the development of electromagnetic Kelvin Helmholtz instability with similar characteristics as that predicted by the electron Magnetohydrodynamic (EMHD) model. On other hand, in strong relativistic case the compressibility effects of electron fluid dominate and introduce upper hybrid electrostatic oscillations transverse to the flow which are very distinct from EMHD fluid behaviour. In the nonlinear regime, both weak and strong relativistic cases lead to turbulence with broad power law spectrum.
Relativistic electromagnetic mass models in spherically symmetric spacetime
Maurya, S K; Ray, Saibal; Chatterjee, Vikram
2015-01-01
Under the static spherically symmetric Einstein-Maxwell spacetime of embedding class one we explore possibility of electromagnetic mass model where mass and other physical parameters have purely electromagnetic origin (Tiwari 1984, Gautreau 1985, Gron 1985). This work is in continuation of our earlier investigation (Maurya 2015a) where we developed an algorithm and found out three new solutions of electromagnetic mass models. In the present letter we consider different metric potentials $\
The nucleon and Delta-resonance masses in relativistic chiral effective-field theory
V. Pascalutsa; M. Vanderhaeghen
2005-11-28
We study the chiral behavior of the nucleon and De-isobar masses within a manifestly covariant chiral effective-field theory, consistent with the analyticity principle. We compute the {pi} N and {pi}{Delta} one-loop contributions to the mass and field-normalization constant, and find that they can be described in terms of universal relativistic loop functions, multiplied by appropriate spin, isospin and coupling constants. We show that these relativistic one-loop corrections, when properly renormalized, obey the chiral power-counting and vanish in the chiral limit. The results including only the {pi} N-loop corrections compare favorably with the lattice QCD data for the pion-mass dependence of the nucleon and De masses, while inclusion of the {pi}/De loops tends to spoil this agreement.
Simulation of the relativistic electron dynamics and acceleration in a linearly-chirped laser pulse
Jisrawi, Najeh M; Salamin, Yousef I
2014-01-01
Theoretical investigations are presented, and their results are discussed, of the laser acceleration of a single electron by a chirped pulse. Fields of the pulse are modeled by simple plane-wave oscillations and a $\\cos^2$ envelope. The dynamics emerge from analytic and numerical solutions to the relativistic Lorentz-Newton equations of motion of the electron in the fields of the pulse. All simulations have been carried out by independent Mathematica and Python codes, with identical results. Configurations of acceleration from a position of rest as well as from injection, axially and sideways, at initial relativistic speeds are studied.
Relativistic Electrons Produced by Foreshock Disturbances Observed Upstream of Earth's Bow Shock
Wilson, L. B.; Sibeck, D. G.; Turner, D. L.; Osmane, A.; Caprioli, D.; Angelopoulos, V.
2016-11-01
Charged particles can be reflected and accelerated by strong (i.e., high Mach number) astrophysical collisionless shock waves, streaming away to form a foreshock region in communication with the shock. Foreshocks are primarily populated by suprathermal ions that can generate foreshock disturbances—large-scale (i.e., tens to thousands of thermal ion Larmor radii), transient (˜5 - 10 per day ) structures. They have recently been found to accelerate ions to energies of several keV. Although electrons in Saturn's high Mach number (M >40 ) bow shock can be accelerated to relativistic energies (nearly 1000 keV), it has hitherto been thought impossible to accelerate electrons beyond a few tens of keV at Earth's low Mach number (1 ≤M events. These relativistic electrons are not associated with any solar or magnetospheric activity. Further, due to their relatively small Larmor radii (compared to magnetic gradient scale lengths) and large thermal speeds (compared to shock speeds), no known shock acceleration mechanism can energize thermal electrons up to relativistic energies. The discovery of relativistic electrons associated with foreshock structures commonly generated in astrophysical shocks could provide a new paradigm for electron injections and acceleration in collisionless plasmas.
Relativistic contributions to single and double core electron ionization energies of noble gases.
Niskanen, J; Norman, P; Aksela, H; Agren, H
2011-08-07
We have performed relativistic calculations of single and double core 1s hole states of the noble gas atoms in order to explore the relativistic corrections and their additivity to the ionization potentials. Our study unravels the interplay of progression of relaxation, dominating in the single and double ionization potentials of the light elements, versus relativistic one-electron effects and quantum electrodynamic effects, which dominate toward the heavy end. The degree of direct relative additivity of the relativistic corrections for the single electron ionization potentials to the double electron ionization potentials is found to gradually improve toward the heavy elements. The Dirac-Coulomb Hamiltonian is found to predict a scaling ratio of ∼4 for the relaxation induced relativistic energies between double and single ionization. Z-scaling of the computed quantities were obtained by fitting to power law. The effects of nuclear size and form were also investigated and found to be small. The results indicate that accurate predictions of double core hole ionization potentials can now be made for elements across the full periodic table.
Larchenkova, T. I.; Lutovinov, A. A.; Lyskova, N. S.
2011-01-01
The images of relativistic jets from extragalactic sources produced by gravitational lensing by galaxies with different mass surface density distributions are modeled. In particular, the following models of the gravitational lens mass distribution are considered: a singular isothermal ellipsoid, an isothermal ellipsoid with a core, two- and three-component models with a galactic disk, halo, and bulge. The modeled images are compared both between themselves and with available observations. Dif...
Turner, D. L.; O'Brien, T. P.; Fennell, J. F.; Claudepierre, S. G.; Blake, J. B.; Jaynes, A. N.; Baker, D. N.; Kanekal, S.; Gkioulidou, M.; Henderson, M. G.; Reeves, G. D.
2017-01-01
Using observations from NASA's Van Allen Probes, we study the role of sudden particle enhancements at low L shells (SPELLS) as a source of inner radiation belt electrons. SPELLS events are characterized by electron intensity enhancements of approximately an order of magnitude or more in less than 1 day at L belt electrons under quiet/average conditions. During SPELLS events, the evolution of electron distributions reveals an enhancement of phase space density that can exceed 3 orders of magnitude in the slot region and continues into the inner radiation belt, which is evidence that these events are an important - and potentially dominant - source of inner belt electrons. Electron fluxes from September 2012 through February 2016 reveal that SPELLS occur frequently ( 2.5/month at 200 keV), but the number of observed events decreases exponentially with increasing electron energy for ≥100 keV. After SPELLS events, the slot region reforms due to slow energy-dependent decay over several day time scales, consistent with losses due to interactions with plasmaspheric hiss. Combined, these results indicate that the peaked phase space density distributions in the inner electron radiation belt result from an "on/off," geomagnetic-activity-dependent source from higher radial distances.
Vitória, R.L.L.; Furtado, C., E-mail: furtado@fisica.ufpb.br; Bakke, K., E-mail: kbakke@fisica.ufpb.br
2016-07-15
The relativistic quantum dynamics of an electrically charged particle subject to the Klein–Gordon oscillator and the Coulomb potential is investigated. By searching for relativistic bound states, a particular quantum effect can be observed: a dependence of the angular frequency of the Klein–Gordon oscillator on the quantum numbers of the system. The meaning of this behaviour of the angular frequency is that only some specific values of the angular frequency of the Klein–Gordon oscillator are permitted in order to obtain bound state solutions. As an example, we obtain both the angular frequency and the energy level associated with the ground state of the relativistic system. Further, we analyse the behaviour of a relativistic position-dependent mass particle subject to the Klein–Gordon oscillator and the Coulomb potential.
Vitória, R. L. L.; Furtado, C.; Bakke, K.
2016-07-01
The relativistic quantum dynamics of an electrically charged particle subject to the Klein-Gordon oscillator and the Coulomb potential is investigated. By searching for relativistic bound states, a particular quantum effect can be observed: a dependence of the angular frequency of the Klein-Gordon oscillator on the quantum numbers of the system. The meaning of this behaviour of the angular frequency is that only some specific values of the angular frequency of the Klein-Gordon oscillator are permitted in order to obtain bound state solutions. As an example, we obtain both the angular frequency and the energy level associated with the ground state of the relativistic system. Further, we analyse the behaviour of a relativistic position-dependent mass particle subject to the Klein-Gordon oscillator and the Coulomb potential.
Niu, YiFei; Vretenar, Dario; Meng, Jie
2011-01-01
We introduce a self-consistent microscopic theoretical framework for modelling the process of electron capture on nuclei in stellar environment, based on relativistic energy density functionals. The finite-temperature relativistic mean-field model is used to calculate the single-nucleon basis and the occupation factors in a target nucleus, and $J^{\\pi} = 0^{\\pm}$, $1^{\\pm}$, $2^{\\pm}$ charge-exchange transitions are described by the self-consistent finite-temperature relativistic random-phase approximation. Cross sections and rates are calculated for electron capture on 54,56Fe and 76,78Ge in stellar environment, and results compared with predictions of similar and complementary model calculations.
Relativistic electromagnetic mass models in spherically symmetric spacetime
Maurya, S. K.; Gupta, Y. K.; Ray, Saibal; Chatterjee, Vikram
2016-10-01
Under the static spherically symmetric Einstein-Maxwell spacetime of embedding class one we explore possibility of constructing electromagnetic mass model where mass and other physical parameters have purely electromagnetic origin (Lorentz in Proc. Acad. Sci. Amst. 6, 1904). This work is in continuation of our earlier investigation of Maurya et al. (Eur. Phys. J. C 75:389, 2015a) where we developed an algorithm and found out three new solutions of electromagnetic mass model. In the present work we consider different metric potentials ν and λ and have analyzed them in a systematic way. It is observed that some of the previous solutions related to electromagnetic mass model are nothing but special cases of the presently obtained generalized solution set. We further verify the solution set and especially show that these are extremely applicable in the case of compact stars.
Schönlein, A.; Boutoux, G.; Pikuz, S.; Antonelli, L.; Batani, D.; Debayle, A.; Franz, A.; Giuffrida, L.; Honrubia, J. J.; Jacoby, J.; Khaghani, D.; Neumayer, P.; Rosmej, O. N.; Sakaki, T.; Santos, J. J.; Sauteray, A.
2016-05-01
We studied the interaction of a high-intensity laser with mass-limited Ti-wires. The laser was focused up to 7× 1020 \\text{W/cm}2 , with contrast of 10-10 to produce relativistic electrons. High-spatial-resolution X-ray spectroscopy was used to measure isochoric heating induced by hot electrons propagating along the wire up to 1 mm depth. For the first time it was possible to distinguish surface target regions heated by mixed plasma mechanisms from those heated only by the hot electrons that generate warm dense matter with temperatures up to 50 eV. Our results are compared to simulations that highlight both the role of electron confinement inside the wire and the importance of resistive stopping powers in warm dense matter.
Zheleznyakov, V. V.; Bespalov, P. A.
2016-04-01
In part I of this work [1], we study the dispersion characteristics of low-frequency waves in a relativistic electron-positron plasma. In part II, we examine the electromagnetic wave instability in this plasma caused by an admixture of nonrelativistic protons with energy comparable with the energy of relativistic low-mass particles. The instability occurs in the frequency band between the fundamental harmonic of proton gyrofrequency and the fundamental harmonic of relativistic electron gyrofrequency. The results can be used for the interpretation of known observations of the pulsar emissions obtained with a high time and frequency resolution. The considered instability can probably be the initial stage of the microwave radio emission nanoshots typical of the pulsar in the Crab Nebula.
Arzeliès, Henri
1972-01-01
Relativistic Point Dynamics focuses on the principles of relativistic dynamics. The book first discusses fundamental equations. The impulse postulate and its consequences and the kinetic energy theorem are then explained. The text also touches on the transformation of main quantities and relativistic decomposition of force, and then discusses fields of force derivable from scalar potentials; fields of force derivable from a scalar potential and a vector potential; and equations of motion. Other concerns include equations for fields; transfer of the equations obtained by variational methods int
Relativistic Electron Shock Drift Acceleration in Low Mach Number Galaxy Cluster Shocks
Matsukiyo, Shuichi; Yamazaki, Ryo; Umeda, Takayuki
2011-01-01
An extreme case of electron shock drift acceleration in low Mach number collisionless shocks is investigated as a plausible mechanism of initial acceleration of relativistic electrons in large-scale shocks in galaxy clusters where upstream plasma temperature is of the order of 10 keV and a degree of magnetization is not too small. One-dimensional electromagnetic full particle simulations reveal that, even though a shock is rather moderate, a part of thermal incoming electrons are accelerated and reflected through relativistic shock drift acceleration and form a local nonthermal population just upstream of the shock. The accelerated electrons can self-generate local coherent waves and further be back-scattered toward the shock by those waves. This may be a scenario for the first stage of the electron shock acceleration occurring at the large-scale shocks in galaxy clusters such as CIZA J2242.8+5301 which has well defined radio relics.
Saito, Shinji; Miyoshi, Yoshizumi; Seki, Kanako
2016-07-01
Wave-particle interactions with whistler chorus waves are believed to provide a primary acceleration for electrons in the outer radiation belt. Previous models for flux enhancement of the radiation belt have assumed the stochastic process as a diffusion manner of successive random-phase interactions, but physical mechanisms for the acceleration are not fully incorporated in these models because of the lack of a nonlinear scattering process. Here we report rapid increase in relativistic electron flux by using an innovative computer simulation model that incorporates not only diffusive process but also nonlinear scattering processes. The simulations show that three types of scattering simultaneously occur, which are diffusive, phase trapping, and phase bunching. It is found that the phase trapping is the most efficient mechanism to produce the MeV electrons rapidly in the scattering processes. The electrons are accelerated from 400 keV to over 1 MeV in time scale less than 60 s. On the other hand, as the phase trapping is suppressed by the breaking of relative phase angle between waves and gyrating electrons during the interaction, the increase of electron flux at MeV energy is clearly reduced. Our simulations conclude that the phase-trapping process causes a significant effect for the increase in relativistic electron flux and suggest that a quasi-linear diffusion model is not always valid to fully describe the relativistic electron acceleration.
Acceleration of positrons by a relativistic electron beam in the presence of quantum effects
Niknam, A. R. [Laser and Plasma Research Institute, Shahid Beheshti University, G.C., Tehran (Iran, Islamic Republic of); Aki, H.; Khorashadizadeh, S. M. [Physics Department, Birjand University, Birjand (Iran, Islamic Republic of)
2013-09-15
Using the quantum magnetohydrodynamic model and obtaining the dispersion relation of the Cherenkov and cyclotron waves, the acceleration of positrons by a relativistic electron beam is investigated. The Cherenkov and cyclotron acceleration mechanisms of positrons are compared together. It is shown that growth rate and, therefore, the acceleration of positrons can be increased in the presence of quantum effects.
Three dimensional filamentary structures of a relativistic electron beam in Fast Ignition plasmas
Karmakar, Anupam; Pukhov, Alexander
2008-01-01
The filamentary structures and associated electromagnetic fields of a relativistic electron beam have been studied by three dimensional particle-in-cell (PIC) simulations in the context of Fast Ignition fusion. The simulations explicitly include collisions in return plasma current and distinctly examine the effects of beam temperature and collisions on the growth of filamentary structures generated.
Generation of ultra-short relativistic-electron-bunch by a laser wakefield
Khachatryan, A.G.; Boller, K.-J.; Goor, van F.A.
2003-01-01
The possibility of the generation of an ultra-short (about one micron long) relativistic (up to a few GeVs) electron-bunch in a moderately nonlinear laser wakefield excited in an underdense plasma by an intense laser pulse is investigated. The ultra-short bunch is formed by trapping, effective compr
Calculation of inelastic scattering processes of relativistic electrons in oriented crystals
Hinderks, Dieter; Kohl, Helmut
2015-04-15
The inelastic scattering of electrons in oriented crystals has been used to determine the positions of atoms within a crystal, to obtain site-dependent electron energy loss spectra and, more recently, to obtain an energy loss signal corresponding to the circular dichroism in X-ray absorption spectroscopy. The theoretical approaches currently used for the description of these processes are based on the nonrelativistic Schrödinger equation. Nowadays many experiments, however, are conducted with incident energies of 200 or 300 keV. Therefore it is indispensable to use a relativistic description for such processes based on the Dirac equation. Using the Coulomb gauge it is shown, that the fully relativistic cross sections for plane wave scattering are given by the modulus square of a sum of two terms: one describing the electrostatic interactions similar to the nonrelativistic theory plus one additional term describing the interaction of the specimen with the magnetic field produced by the incident electron. In crystals both terms can interfere leading to large deviations from nonrelativistic theory. - Highlights: • Inelastic scattering of relativistic electrons in oriented crystals is described. • We have derived equations for relativistic Bloch waves. • Strong deviations from nonrelativistic theory have been demonstrated.
Hidalgo-Gato, Rafael A Valls
2012-01-01
From a rigorous historic analysis of 1686 I. Newton and 1905 A. Einstein works where the last derived the universal mass-energy relationship, it is concluded that rest mass measures potential energy. From the same formula used to obtain that relation, it is derived the ratio Total Energy/Potential Energy is equal to the gamma relativistic factor. It is derived a formula for the variation of a body rest mass with its position in a gravity field, explaining with it the behavior of an atomic clock. It is revised the bodies free fall in a gravitational field, finding that a constant total mass is equal to the gravitational mass, while the variable rest mass is equal to the inertial mass, maintaining all an identical behavior independent of their masses. A revision of the E\\"otv\\"os experiment concludes that it is unable to detect the found difference between inertial and gravitational mass. Applying the extended 1905 relativistic dynamics to Mercury, its perihelion shift is determined; it is concluded with the co...
CURRENT SHEET REGULATION OF SOLAR NEAR-RELATIVISTIC ELECTRON INJECTION HISTORIES
Agueda, N.; Sanahuja, B. [Departament d' Astronomia i Meteorologia, Institut de Ciencies del Cosmos, Universitat de Barcelona (Spain); Vainio, R. [Department of Physics, University of Helsinki (Finland); Dalla, S. [Jeremiah Horrocks Institute, University of Central Lancashire (United Kingdom); Lario, D. [Applied Physics Laboratory, Johns Hopkins University (United States)
2013-03-10
We present a sample of three large near-relativistic (>50 keV) electron events observed in 2001 by both the ACE and the Ulysses spacecraft, when Ulysses was at high-northern latitudes (>60 Degree-Sign ) and close to 2 AU. Despite the large latitudinal distance between the two spacecraft, electrons injected near the Sun reached both heliospheric locations. All three events were associated with large solar flares, strong decametric type II radio bursts and accompanied by wide (>212 Degree-Sign ) and fast (>1400 km s{sup -1}) coronal mass ejections (CMEs). We use advanced interplanetary transport simulations and make use of the directional intensities observed in situ by the spacecraft to infer the electron injection profile close to the Sun and the interplanetary transport conditions at both low and high latitudes. For the three selected events, we find similar interplanetary transport conditions at different heliolatitudes for a given event, with values of the mean free path ranging from 0.04 AU to 0.27 AU. We find differences in the injection profiles inferred for each spacecraft. We investigate the role that sector boundaries of the heliospheric current sheet (HCS) have on determining the characteristics of the electron injection profiles. Extended injection profiles, associated with coronal shocks, are found if the magnetic footpoints of the spacecraft lay in the same magnetic sector as the associated flare, while intermittent sparse injection episodes appear when the spacecraft footpoints are in the opposite sector or a wrap in the HCS bounded the CME structure.
Artemyev, A. V., E-mail: ante0226@gmail.com [Space Research Institute, RAS, Moscow (Russian Federation); Mourenas, D.; Krasnoselskikh, V. V. [LPC2E/CNRS - University of Orleans, Orleans (France); Agapitov, O. V. [Space Sciences Laboratory, University of California, Berkeley, California 94720 (United States)
2015-06-15
In this paper, we study relativistic electron scattering by fast magnetosonic waves. We compare results of test particle simulations and the quasi-linear theory for different spectra of waves to investigate how a fine structure of the wave emission can influence electron resonant scattering. We show that for a realistically wide distribution of wave normal angles θ (i.e., when the dispersion δθ≥0.5{sup °}), relativistic electron scattering is similar for a wide wave spectrum and for a spectrum consisting in well-separated ion cyclotron harmonics. Comparisons of test particle simulations with quasi-linear theory show that for δθ>0.5{sup °}, the quasi-linear approximation describes resonant scattering correctly for a large enough plasma frequency. For a very narrow θ distribution (when δθ∼0.05{sup °}), however, the effect of a fine structure in the wave spectrum becomes important. In this case, quasi-linear theory clearly fails in describing accurately electron scattering by fast magnetosonic waves. We also study the effect of high wave amplitudes on relativistic electron scattering. For typical conditions in the earth's radiation belts, the quasi-linear approximation cannot accurately describe electron scattering for waves with averaged amplitudes >300 pT. We discuss various applications of the obtained results for modeling electron dynamics in the radiation belts and in the Earth's magnetotail.
On the Production of Relativistic Runaway Electrons in Damavand Tokamak
Moslehi-Fard, Mahmoud
2013-02-01
Experimental observations in Damavand tokamak show that hard X-ray is produced by either disruption with I p 20 kA. Hard X-ray also persists from the initiation of plasma discharge to the end. Occurrence of multiple spikes in hard X-ray during the discharge is evident. The propagation of hard X-ray is attributed to runaway electrons. We observe runaway electrons in two regimes with different characteristics. Regime (RADI) is similar to the observations of other Tokamak during disruption on that the plasma current is reduced abruptly and interpreted by Dreicer theory. In the regime of RADII, hard X-ray and subsequently runaway electrons are observed from starting of plasma discharge which provides the condition that the most of runaway electrons contain the toroidal plasma current. Runaway electron beam excites whistler waves and scattered electrons in velocity space and prevent growing the runaway electrons beam.
Novel Aspects of Direct Laser Acceleration of Relativistic Electrons
Arefiev, A V; Khudik, V N
2015-01-01
We examine the impact of several factors on electron acceleration by a laser pulse and the resulting electron energy gain. Specifically, we consider the role played by: 1) static longitudinal electric field; 2) static transverse electric field; 3) electron injection into the laser pulse; and 4) static longitudinal magnetic field. It is shown that all of these factors lead, under certain conditions, to a considerable electron energy gain from the laser pulse. In contrast with other mechanisms such as wakefield acceleration, the static electric fields in this case do not directly transfer substantial energy to the electron. Instead, they reduce the longitudinal dephasing between the electron and the laser beam, which then allows the electron to gain extra energy from the beam. The mechanisms discussed here are relevant to experiments with under-dense gas jets, as well as to experiments with solid-density targets involving an extended pre-plasma.
Delta isobars in relativistic mean-field models with $\\sigma$-scaled hadron masses and couplings
Kolomeitsev, E E; Voskresensky, D N
2016-01-01
We extend the relativistic mean-field models with hadron masses and meson-baryon coupling constants dependent on the scalar $\\sigma$ field, studied previously to incorporate $\\Delta(1232)$ baryons. Available empirical information is analyzed to put constraints on the couplings of $\\Delta$s with meson fields. Conditions for the appearance of $\\Delta$s are studied. We demonstrate that with inclusion of the $\\Delta$s our equations of state continue to fulfill majority of known empirical constraints including the pressure-density constraint from heavy-ion collisions, the constraint on the maximum mass of the neutron stars, the direct Urca and the gravitational-baryon mass ratio constraints.
Abdikian, A.; Mahmood, S.
2016-12-01
The obliquely nonlinear acoustic solitary propagation in a relativistically quantum magnetized electron-positron (e-p) plasma in the presence of the external magnetic field as well as the stationary ions for neutralizing the plasma background was studied. By considering the dynamic of the fluid e-p quantum and by using the quantum hydrodynamics model and the standard reductive perturbation technique, the Zakharov-Kuznetsov (ZK) equation is derived for small but finite amplitude waves and the solitary wave solution for the parameters relevant to dense astrophysical objects such as white dwarf stars is obtained. The numerical results show that the relativistic effects lead to propagate the electrostatic bell shape structures in quantum e-p plasmas like those in classical pair-ion or pair species for relativistic plasmas. It is also observed that by increasing the relativistic effects, the amplitude and width of the e-p acoustic solitary wave will decrease. In addition, the wave amplitude increases as positron density decreases in magnetized e-p plasmas. It is indicated that by increasing the strength of the magnetic field, the width of the soliton reduces and it becomes sharper. At the end, we have analytically and numerically shown that the pulse soliton solution of the ZK equation is unstable and have traced the dependence of the instability growth rate on electron density. It is found that by considering the relativistic pressure, the instability of the soliton pulse can be reduced. The results can be useful to study the obliquely nonlinear propagation of small amplitude localized structures in magnetized quantum e-p plasmas and be applicable to understand the particle and energy transport mechanism in compact stars such as white dwarfs, where the effects of relativistic electron degeneracy become important.
Hafez, M. G.; Talukder, M. R.
2015-09-01
This work investigates the theoretical and numerical studies on nonlinear propagation of ion acoustic solitary waves (IASWs) in an unmagnetized plasma consisting of nonextensive electrons, Boltzmann positrons and relativistic thermal ions. The Korteweg-de Vries (KdV) equation is derived by using the well known reductive perturbation method. This equation admits the soliton like solitary wave solution. The effects of phase velocity, amplitude of soliton, width of soliton and electrostatic nonlinear propagation of weakly relativistic ion-acoustic solitary waves have been discussed with graphical representation found in the variation of the plasma parameters. The obtained results can be helpful in understanding the features of small but finite amplitude localized relativistic ion-acoustic waves for an unmagnetized three component plasma system in astrophysical compact objects.
Storage-ring Electron Cooler for Relativistic Ion Beams
Lin, Fanglei [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Derbenev, Yaroslav [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Douglas, David R. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Guo, Jiquan [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Johnson, Rolland P. [Muons Inc., Batavia, IL (United States); Krafft, Geoffrey A. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Morozov, Vasiliy [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Zhang, Yuhong [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)
2016-05-01
Application of electron cooling at ion energies above a few GeV has been limited due to reduction of electron cooling efficiency with energy and difficulty in producing and accelerating a high-current high-quality electron beam. A high-current storage-ring electron cooler offers a solution to both of these problems by maintaining high cooling beam quality through naturally-occurring synchrotron radiation damping of the electron beam. However, the range of ion energies where storage-ring electron cooling can be used has been limited by low electron beam damping rates at low ion energies and high equilibrium electron energy spread at high ion energies. This paper reports a development of a storage ring based cooler consisting of two sections with significantly different energies: the cooling and damping sections. The electron energy and other parameters in the cooling section are adjusted for optimum cooling of a stored ion beam. The beam parameters in the damping section are adjusted for optimum damping of the electron beam. The necessary energy difference is provided by an energy recovering SRF structure. A prototype linear optics of such storage-ring cooler is presented.
Coherent X-ray radiation excited by a diverging relativistic electron beam in a single crystal
Blazhevich, S. V., E-mail: noskovbupk@mail.ru; Noskov, A. V. [Belgorod State National Research University (Russian Federation)
2015-05-15
We develop a dynamic theory of coherent X-rays generated in a single-crystal wafer by a diverging relativistic electron beam. The dependence of the spectral-angular density of coherent X-ray radiation on the angle of divergence is analyzed for the case when the angular spread can be described by the 2D Gaussian distribution. The theory constructed here makes it possible to analyze coherent radiation for an arbitrary angular distribution of electrons in the beam as well.
Explosive Emission and Gap Closure from a Relativistic Electron Beam Diode
2013-06-01
voltage rises on the blumlein. Second, the intrinsic impedance of the BPM and E-dot are most certainly different. The BPM is a short at low frequency...was supported by the National Nuclear Security Administration of the U.S. Department of Energy under ξ email: jecoleman@lanl.gov Abstract...These electrons are either accelerated and extracted to produce an intense relativistic electron beam, or they are terminated into a solid or
Mei Symmetry and Noether Symmetry of the Relativistic Variable Mass System
FANG Jian-Hui
2004-01-01
The definition and criterion of the Mei symmetry of a relativistic variable mass system are given. The relation between the Mei symmetry and the Noether symmetry of the system is found under infinitesimal transformations of groups. The conserved quantities to which the Mei symmetry and Noether symmetry of the system lead are obtained.An example is given to illustrate the application of the result.
Ultra-relativistic electrons in Jupiter's radiation belts.
Bolton, S J; Janssen, M; Thorne, R; Levin, S; Klein, M; Gulkis, S; Bastian, T; Sault, R; Elachi, C; Hofstadter, M; Bunker, A; Dulk, G; Gudim, E; Hamilton, G; Johnson, W T K; Leblanc, Y; Liepack, O; McLeod, R; Roller, J; Roth, L; West, R
2002-02-28
Ground-based observations have shown that Jupiter is a two-component source of microwave radio emission: thermal atmospheric emission and synchrotron emission from energetic electrons spiralling in Jupiter's magnetic field. Later in situ measurements confirmed the existence of Jupiter's high-energy electron-radiation belts, with evidence for electrons at energies up to 20[?]MeV. Although most radiation belt models predict electrons at higher energies, adiabatic diffusion theory can account only for energies up to around 20[?]MeV. Unambiguous evidence for more energetic electrons is lacking. Here we report observations of 13.8[?]GHz synchrotron emission that confirm the presence of electrons with energies up to 50[?]MeV; the data were collected during the Cassini fly-by of Jupiter. These energetic electrons may be repeatedly accelerated through an interaction with plasma waves, which can transfer energy into the electrons. Preliminary comparison of our data with model results suggests that electrons with energies of less than 20[?]MeV are more numerous than previously believed.
Storage-ring Electron Cooler for Relativistic Ion Beams
Lin, F; Douglas, D; Guo, J; Johnson, R P; Krafft, G; Morozov, V S; Zhang, Y
2016-01-01
Application of electron cooling at ion energies above a few GeV has been limited due to reduction of electron cooling efficiency with energy and difficulty in producing and accelerating a high-current high-quality electron beam. A high-current storage-ring electron cooler offers a solution to both of these problems by maintaining high cooling beam quality through naturally-occurring synchrotron radiation damping of the electron beam. However, the range of ion energies where storage-ring electron cooling can be used has been limited by low electron beam damping rates at low ion energies and high equilibrium electron energy spread at high ion energies. This paper reports a development of a storage ring based cooler consisting of two sections with significantly different energies: the cooling and damping sections. The electron energy and other parameters in the cooling section are adjusted for optimum cooling of a stored ion beam. The beam parameters in the damping section are adjusted for optimum damping of the...
Uzbekov, Bogdan; Shprits, Yuri Y.; Orlova, Ksenia
2016-10-01
Electromagnetic Ion Cyclotron (EMIC) waves are transverse plasma waves that are generated in the Earth magnetosphere by ring current protons with temperature anisotropy in three different bands: below the H+, He+ and O+ ion gyrofrequencies. EMIC events are enhanced during the main phase of a geomagnetic storm when intensifications in the electric field result in enhanced injections of ions and are usually confined to high-density regions just inside the plasmapause or within drainage plumes. EMIC waves are capable of scattering radiation belt electrons and thus provide an important link between the intensification of the electric field, ion populations, and radiation belt electrons. Bounce-averaged diffusion coefficients computed with the assumption of parallel wave propagation are compared to the results of the code that uses the full cold plasma dispersion relation taking into account oblique propagation of waves and higher-order resonances. We study the sensitivity of the scattering rates to a number of included higher-order resonances, wave spectral distribution parameters, wave normal angle distribution parameters, ambient plasma density, and ion composition. Inaccuracies associated with the neglect of higher-order resonances and oblique propagation of waves are compared to potential errors introduced by uncertainties in the model input parameters.
Sahai, Aakash A., E-mail: aakash.sahai@gmail.com [Department of Electrical Engineering, Duke University, Durham, North Carolina 27708 (United States)
2014-05-15
We analyze the motion of the plasma critical layer by two different processes in the relativistic-electron laser-plasma interaction regime (a{sub 0}>1). The differences are highlighted when the critical layer ions are stationary in contrast to when they move with it. Controlling the speed of the plasma critical layer in this regime is essential for creating low-β traveling acceleration structures of sufficient laser-excited potential for laser ion accelerators. In Relativistically Induced Transparency Acceleration (RITA) scheme, the heavy plasma-ions are fixed and only trace-density light-ions are accelerated. The relativistic critical layer and the acceleration structure move longitudinally forward by laser inducing transparency through apparent relativistic increase in electron mass. In the Radiation Pressure Acceleration (RPA) scheme, the whole plasma is longitudinally pushed forward under the action of the laser radiation pressure, possible only when plasma ions co-propagate with the laser front. In RPA, the acceleration structure velocity critically depends upon plasma-ion mass in addition to the laser intensity and plasma density. In RITA, mass of the heavy immobile plasma-ions does not affect the speed of the critical layer. Inertia of the bared immobile ions in RITA excites the charge separation potential, whereas RPA is not possible when ions are stationary.
Sahai, Aakash A.
2014-05-01
We analyze the motion of the plasma critical layer by two different processes in the relativistic-electron laser-plasma interaction regime (a0>1). The differences are highlighted when the critical layer ions are stationary in contrast to when they move with it. Controlling the speed of the plasma critical layer in this regime is essential for creating low-β traveling acceleration structures of sufficient laser-excited potential for laser ion accelerators. In Relativistically Induced Transparency Acceleration (RITA) scheme, the heavy plasma-ions are fixed and only trace-density light-ions are accelerated. The relativistic critical layer and the acceleration structure move longitudinally forward by laser inducing transparency through apparent relativistic increase in electron mass. In the Radiation Pressure Acceleration (RPA) scheme, the whole plasma is longitudinally pushed forward under the action of the laser radiation pressure, possible only when plasma ions co-propagate with the laser front. In RPA, the acceleration structure velocity critically depends upon plasma-ion mass in addition to the laser intensity and plasma density. In RITA, mass of the heavy immobile plasma-ions does not affect the speed of the critical layer. Inertia of the bared immobile ions in RITA excites the charge separation potential, whereas RPA is not possible when ions are stationary.
Hajra, Rajkumar; Tsurutani, Bruce T.; Echer, Ezequiel; Gonzalez, Walter D.; Brum, Christiano Garnett Marques; Vieira, Luis Eduardo Antunes; Santolik, Ondrej
2015-07-01
We present a comparative study of high-intensity long-duration continuous AE activity (HILDCAA) events, both isolated and those occurring in the "recovery phase" of geomagnetic storms induced by corotating interaction regions (CIRs). The aim of this study is to determine the difference, if any, in relativistic electron acceleration and magnetospheric energy deposition. All HILDCAA events in solar cycle 23 (from 1995 through 2008) are used in this study. Isolated HILDCAA events are characterized by enhanced fluxes of relativistic electrons compared to the pre-event flux levels. CIR magnetic storms followed by HILDCAA events show almost the same relativistic electron signatures. Cluster 1 spacecraft showed the presence of intense whistler-mode chorus waves in the outer magnetosphere during all HILDCAA intervals (when Cluster data were available). The storm-related HILDCAA events are characterized by slightly lower solar wind input energy and larger magnetospheric/ionospheric dissipation energy compared with the isolated events. A quantitative assessment shows that the mean ring current dissipation is ~34 % higher for the storm-related events relative to the isolated events, whereas Joule heating and auroral precipitation display no (statistically) distinguishable differences. On the average, the isolated events are found to be comparatively weaker and shorter than the storm-related events, although the geomagnetic characteristics of both classes of events bear no statistically significant difference. It is concluded that the CIR storms preceding the HILDCAAs have little to do with the acceleration of relativistic electrons. Our hypothesis is that ~10-100-keV electrons are sporadically injected into the magnetosphere during HILDCAA events, the anisotropic electrons continuously generate electromagnetic chorus plasma waves, and the chorus then continuously accelerates the high-energy portion of this electron spectrum to MeV energies.
Nonthermal radiation from relativistic electrons accelerated at spherically expanding shocks
Kang, Hyesung
2014-01-01
We study the evolution of the energy spectrum of cosmic-ray electrons accelerated at spherically expanding shocks with low Mach numbers and the ensuing spectral signatures imprinted in radio synchrotron emission. Time-dependent simulations of diffusive shock acceleration (DSA) of electrons in the test-particle limit have been performed for spherical shocks with the parameters relevant for typical shocks in the intracluster medium. The electron and radiation spectra at the shock location can be described properly by the test-particle DSA predictions with the instantaneous shock parameters. However, the volume integrated spectra of both electrons and radiation deviate significantly from the test-particle power-laws, because the shock compression ratio and the flux of injected electrons at the shock gradually decrease as the shock slows down in time. So one needs to be cautious about interpreting observed radio spectra of evolving shocks by simple DSA models in the test-particle regime.
Terahertz radiation emission from plasma beat-wave interactions with a relativistic electron beam
Gupta, D. N.; Kulagin, V. V.; Suk, H.
2017-10-01
We present a mechanism to generate terahertz radiation from laser-driven plasma beat-wave interacting with an electron beam. The theory of the energy transfer between the plasma beat-wave and terahertz radiation is elaborated through nonlinear coupling in the presence of a negative-energy relativistic electron beam. An expression of terahertz radiation field is obtained to find out the efficiency of the process. Our results show that the efficiency of terahertz radiation emission is strongly sensitive to the electron beam energy. Emitted field strength of the terahertz radiation is calculated as a function of electron beam velocity.
Millan, R. M.; Yando, K.; Green, J. C.
2008-12-01
We present POES observations of relativistic electron precipitation during an electron depletion event observed by GOES and GPS. On January 19, 2000 NOAA-15 passed very near the MAXIS balloon payload (L=4.7) which detected an intense duskside precipitation event (Millan et al., 2007). Recent work has shown that the NOAA MEPED proton detector responds to electrons above ~700 keV. We combine data from this high energy channel with data from the MEPED electron detector to examine the energy distribution and spatial extent of precipitation during this period. The results are compared with the MAXIS balloon observations.
Forecasting relativistic electron flux using dynamic multiple regression models
H.-L. Wei
2011-02-01
Full Text Available The forecast of high energy electron fluxes in the radiation belts is important because the exposure of modern spacecraft to high energy particles can result in significant damage to onboard systems. A comprehensive physical model of processes related to electron energisation that can be used for such a forecast has not yet been developed. In the present paper a systems identification approach is exploited to deduce a dynamic multiple regression model that can be used to predict the daily maximum of high energy electron fluxes at geosynchronous orbit from data. It is shown that the model developed provides reliable predictions.
Explosion of relativistic electron vortices in laser plasmas
Lezhnin, K V; Esirkepov, T Zh; Bulanov, S V; Gu, Y; Weber, S; Korn, G
2016-01-01
The interaction of high intensity laser radiation with underdense plasma may lead to the formation of electron vortices. Though being quasistationary on an electron timescales, these structures tend to expand on a proton timescale due to Coloumb repulsion of ions. Using a simple analytical model of a stationary vortex as initial condition, 2D PIC simulations are performed. A number of effects are observed such as vortex boundary field intensification, multistream instabilities at the vortex boundary, and bending of the vortex boundary with the subsequent transformation into smaller electron vortices.
Relativistic frozen core potential scheme with relaxation of core electrons
Nakajima, Yuya; Seino, Junji; Hayami, Masao; Nakai, Hiromi
2016-10-01
This letter proposes a relaxation scheme for core electrons based on the frozen core potential method at the infinite-order Douglas-Kroll-Hess level, called FCP-CR. The core electrons are self-consistently relaxed using frozen molecular valence potentials after the valence SCF calculation is performed. The efficiency of FCP-CR is confirmed by calculations of gold clusters. Furthermore, FCP-CR reproduces the results of the all-electron method for the energies of coinage metal dimers and the core ionization energies and core level shifts of vinyl acetate and three tungsten complexes at the Hartree-Fock and/or symmetry-adapted cluster configuration interaction levels.
Relativistic Dirac Representation of Dynamically-Generated Elementary-Particle Mass
Chew, Geoffrey F
2008-01-01
Special-relativistic dynamically-generated elementary-particle mass is represented by a self-adjoint energy operator acting on a rigged Hilbert space (RHS) of functions over the 6-dimensional Euclidean-group manifold. Even though this operator's eigenvalues correspond to total energy, it is not the generator of infinitesimal wave-function evolution in classical time. Extending formalism which Dirac invented and applied non-relativistically, unitary Poincar\\'e-group representation is provided by the wave functions of a spacelike entity that we call "preon". Six continuous Feynman-path-contacting preon coordinates specify spatial location (3 coordinates), lightlike-velocity-direction (2 coordinates) and transverse polarization (1 coordinate). [Utility of the the term "preon observable" is dubious.] Velocity and spatial location collaborate to define a preon time operator conjugate to the energy operator. In RHS bases alternative to functions over the group manifold, the wave function depends on a preon "velocit...
Systematic nuclear structure studies using relativistic mean field theory in mass region A ˜ 130
Shukla, A.; Åberg, Sven; Bajpeyi, Awanish
2017-02-01
Nuclear structure studies for even-even nuclei in the mass region \\backsim 130, have been performed, with a special focus around N or Z = 64. On the onset of deformation and lying between two closed shell, these nuclei have attracted attention in a number of studies. A revisit to these experimentally accessible nuclei has been made via the relativistic mean field. The role of pairing and density depletion in the interior has been specially investigated. Qualitative analysis between two versions of relativistic mean field suggests that there is no significant difference between the two approaches. Moreover, the role of the filling {{{s}}}1/2 orbital in density depletion towards the centre has been found to be consistent with our earlier work on the subject Shukla and Åberg (2014 Phys. Rev. C 89 014329).
Role of the Russell-McPherron Effect in the Acceleration of Relativistic Electrons
McPherron, R. L.; Baker, D. N.; Crooker, N. U.
2010-01-01
While it is well known that high fluxes of relativistic electrons in the Earth's radiation belts are associated with high-speed solar wind and its heightened geoeffectiveness,less known is the fact that the Russell McPherron(R M) effect strongly controls whether or not a given high-speed stream is geoffective. To test whether it then follows that the R M effect also strongly controls fluxes of relativistic electrons, we perform a superposed epoch analysis across corotating interaction regions (CIR) keyed on the interfaces between slow and fast wind. A total of 394 stream interfaces were identified in the years 1994-2006. Equinoctial interfaces were separated into four classes based on the R-M effect,that is, whether the solar wind on either side of the interface was either(geo)effective (E) or ineffective (I) depending on season and the polarity of the interplanetary magnetic field (IMF). Four classes of interface identified as II, IE, EI,and EE are possible. The classes IE and EI correspond to CIRs with polarity changes indicating passage through the heliospheric current sheet. To characterize the behavior of solar wind and magnetospheric variables, we produced maps of dynamic cumulative probability distribution functions (cdfs) as a function of time over 10-day intervals centered on the interfaces. These reveal that effective high-speed streams have geomagnetic activity nearly twice as strong as ineffective streams and electron fluxes a factor of 12 higher. In addition they show that an effective low-speed stream increases the flux of relativistic electrons before the interface so that an effective to ineffective transition results in lower fluxes after the interface.We conclude that the R-M effect plays a major role in organizing and sustaining a sequence of physical processes responsible for the acceleration of relativistic electrons.
Relativistic electron gas: A candidate for nature's left-handed materials
de Carvalho, C. A. A.
2016-05-01
The electric permittivities and magnetic permeabilities for a relativistic electron gas are calculated from quantum electrodynamics at finite temperature and density as functions of temperature, chemical potential, frequency, and wave vector. The polarization and the magnetization depend linearly on both electric and magnetic fields, and are the sum of a zero-temperature and zero-density vacuum part with a temperature- and chemical-potential-dependent medium part. Analytic calculations lead to generalized expressions that depend on three scalar functions. In the nonrelativistic limit, results reproduce the Lindhard formula. In the relativistic case, and in the long wavelength limit, we obtain the following: (i) for ω =0 , generalized susceptibilities that reduce to known nonrelativistic limits; (ii) for ω ≠0 , Drude-type responses at zero temperature. The latter implies that both the electric permittivity ɛ and the magnetic permeability μ may be simultaneously negative, a behavior characteristic of metamaterials. This unambiguously indicates that the relativistic electron gas is one of nature's candidates for the realization of a negative index of refraction system. Moreover, Maxwell's equations in the medium yield the dispersion relation and the index of refraction of the electron gas. Present results should be relevant for plasma physics, astrophysical observations, synchrotrons, and other environments with fast-moving electrons.
A relativistic electron dropout during the storm on June 1 2013
Kang, Suk-Bin; Fok, Mei-Ching; Engebretson, Mark; Komar, Colin; Glocer, Alex; Buzulukova, Natalia
2016-04-01
A flux dropout is a sudden and considerable decrease in the relativistic electron population of the outer radiation belt on the timescale of a few hours. The dropout is generally driven by loss to the atmosphere mainly due to EMIC waves or drift loss to the magnetopause. A significant dropout was observed from Van Allen Probes during the storm on June 1 2013. However, there did not appear that EMIC waves are strong enough to cause considerable precipitating loss of Multi-MeV electrons from both Van Allen Probes and ground-based observatory during this dropout. Moreover, Polar-orbiting Operational Environmental Satellite (POES) rarely detected precipitating flux of > 1 MeV. To understand physical mechanisms of this dropout, we used Comprehensive Inner Magnetosphere and Ionosphere (CIMI) model and simulated flux and phase space density of relativistic electrons without pitch-angle scattering due to EMIC waves. The CIMI simulation using Tsyganenko 2004 magnetic model reproduced the significant dropout. The minimum last closed drift shell calculated by CIMI model was estimated to be L* = 4.55 during this event. CIMI also showed a strong induced-electric field due to displacement of the magnetic field line at the magnetic equator even at L* < 4.55, which can result in outward radial transport of relativistic electrons. We conclude that outward radial transport due to strong induced-electric field and drift loss to the magnetopause are main causes of this dropout.
Hadron Mass Spectra and Decay Rates in a Potential Model with Relativistic Wave Equations.
Namgung, Wuk
Hadron properties of mass spectra and decay rates are calculated in a quark potential model. Wave equations based on the Klein-Gordon and Todorov equations both of which incorporate the feature of relativistic two-body kinematics are used. The wave equations are modified to contain potentials which transform either like a Lorentz scalar or like a time-component of a four-vector. Potentials based on the Fogleman-Lichtenberg-Wills potential which has the properties suggested by QCD of both confinement and asymptotic freedom are used. The potentials, motivated by QCD but otherwise phenomenological, are further generalized to forms which can apply to any color representation. To break the degeneracy between vector and pseudoscalar mesons or between spin-3/2 and spin-1/2 baryons, the essential feature of spin dependence is included in the potentials. The masses of vector and pseudoscalar mesons are calculated with only a small number of adjustable parameters, and good qualitative agreement with experiment is obtained for both heavy and light mesons. Baryons are treated in this framework by making use of a quark-diquark two-body model of baryons. First, diquark properties are calculated without any additional parameters. The g-factors of diquarks and spin-flavor configuration of baryons, which are necessary for the calculation of baryons, are given. Then baryon masses are calculated also without additional parameters. The results of the masses of ground-state baryons are in good qualitative agreement with experiment. Also effective constituent quark masses are obtained using current quark masses as input. The calculated effective constituent quark masses are in the right range of the values that most theoretical estimates have given. The general qualitative features of hadron spectra are similar with the two relativistic wave equations, although there are differences in detail. The Van Royen-Weisskopf formula for electromagnetic decay widths of vector mesons into lepton
Fully Relativistic Electron Impact Excitation Cross-Section and Polarization for Tungsten Ions
Priti
2015-04-01
Full Text Available Electron impact excitation of highly charged tungsten ions in the framework of a fully relativistic distorted wave approach is considered in this paper. Calculations of electron impact excitation cross-sections for the M- and L-shell transitions in the tungsten ions Wn+ (n = 44–66 and polarization of the decay of photons from the excited tungsten ions are briefly reviewed and discussed. New calculations in the wide range of incident electron energies are presented for M-shell transitions in the K-like through Ne-like tungsten ions.
Geant4 simulations on Compton scattering of laser photons on relativistic electrons
Filipescu, D. [Extreme Light Infrastructure - Nuclear Physics, str. Atomistilor nr. 407, Bucharest-Magurele, P.O.BOX MG6, Romania and National Institute for Physics and Nuclear Engineering Horia Hulubei, str. Atomistilor nr. 407 (Romania); Utsunomiya, H. [Department of Physics, Konan University, Okamoto 8-9-1, Higashinada, Kobe 658-8501 (Japan); Gheorghe, I.; Glodariu, T. [National Institute for Physics and Nuclear Engineering Horia Hulubei, str. Atomistilor nr. 407 (Romania); Tesileanu, O. [Extreme Light Infrastructure - Nuclear Physics, str. Atomistilor nr. 407, Bucharest-Magurele, P.O.BOX MG6 (Romania); Shima, T.; Takahisa, K. [Research Center for Nuclear Physics, Osaka University, Suita, Osaka 567-0047 (Japan); Miyamoto, S. [Laboratory of Advanced Science and Technology for Industry, University of Hyogo, 3-1-2 Kouto, Kamigori, Hyogo 678-1205 (Japan)
2015-02-24
Using Geant4, a complex simulation code of the interaction between laser photons and relativistic electrons was developed. We implemented physically constrained electron beam emittance and spacial distribution parameters and we also considered a Gaussian laser beam. The code was tested against experimental data produced at the γ-ray beam line GACKO (Gamma Collaboration Hutch of Konan University) of the synchrotron radiation facility NewSUBARU. Here we will discuss the implications of transverse missallignments of the collimation system relative to the electron beam axis.
Clayton, C. E.; Marsh, K. A.; Dyson, A.; Everett, M.; Lal, A.; Leemans, W. P.; Williams, R.; Joshi, C.
1993-01-01
High-gradient acceleration of externally injected 2.1-MeV electrons by a laser beat wave driven relativistic plasma wave has been demonstrated for the first time. Electrons with energies up to the detection limit of 9.1 MeV were detected when such a plasma wave was resonantly excited using a two-frequency laser. This implies a gradient of 0.7 GeV/m, corresponding to a plasma-wave amplitude of more than 8%. The electron signal was below detection threshold without injection or when the laser was operated on a single frequency.
Zhidkov, A; Bulanov, S S; Hosokai, T; Koga, J; Kodama, R
2013-01-01
Non-linear cascade scattering of intense, tightly focused laser pulses by relativistic electrons is studied numerically in the classical approximation including the radiation damping for the quantum parameter hwx-ray/E<1 and an arbitrary radiation parameter Kai. The electron energy loss, along with its side scattering by the ponderomotive force, makes the scattering in the vicinity of high laser field nearly impossible at high electron energies. The use of a second, co-propagating laser pulse as a booster is shown to solve this problem.
Three-Dimensional PIC-MC Modeling for Relativistic Electron Beam Transport Through Dense Plasma
CAO Lihua; CHANG Tieqiang; PEI Wenbing; LIU Zhanjun; LI Meng; ZHENG Chunyang
2008-01-01
We have developed a three dimensional (3D) PIC (particle-in-cell)-MC (Monte Carlo) code in order to simulate an electron beam transported into the dense matter based on our previous two dimensional code. The relativistic motion of fast electrons is treated by the particle-in-cell method under the influence of both a self-generated transverse magnetic field and an axial electric field, as well as collisions. The electric field generated by return current is ex-pressed by Ohm's law and the magnetic field is calculated from Faraday's law. The slowing down of monoenergy electrons in DT plasma is calculated and discussed.
Kurayev, Alexander A.; Rak, Alexey O.; Sinitsyn, Anatoly K., E-mail: kurayev@bsuir.by [Belarusian State University of Informatics and Radioelectronics, P. Brovka Str., Minsk (Belarus)
2011-07-01
On the basis of the exact nonlinear theory relativistic TWT and BWO on irregular hollow waveguides with cathode filters-modulators with the account as propagating, and beyond cut-off waves, with the account of losses in walls of a waveguide and inhomogeneity directing an electronic beam magnetostatic fields finds out influence of dynamic stratification influence on efficiency of the generator. Possibility of almost fill compensation the electronic beam dynamic stratification influence on efficiency by optimization of an electronic beam arrangement in inhomogeneous high frequency and magnetic fields and characteristics of the irregular corrugated waveguide is shown. (author)
Eliasson, B.; Papadopoulos, K.
2017-10-01
A theoretical study of the propagation of left-hand polarized shear Alfvén waves in spatially decreasing magnetic field geometries near the EMIC resonance, including the spectrum and amplitude of the mode converted EMIC waves and the pitch angle scattering of relativistic electrons transiting the resonant region, is presented. The objective of the paper is to motivate an experimental study of the subject using the UCLA LAPD chamber. The results are relevant in exploring the possibility that shear Alfvén waves strategically injected into the radiation belts using either ionospheric heating from ground based RF transmitters or injected by transmitters based on space platforms can enhance the precipitation rate of trapped relativistic electrons. Effects of multi-ionic composition are also investigated.
Attosecond Control of Relativistic Electron Bunches using Two-Colour Fields
Yeung, M; Bierbach, J; Li, L; Eckner, E; Kuschel, S; Woldegeorgis, A; Rödel, C; Sävert, A; Paulus, G G; Coughlan, M; Dromey, B; Zepf, M
2016-01-01
Energy coupling during relativistically intense laser-matter interactions is encoded in the attosecond motion of strongly driven electrons at the pre-formed plasma-vacuum boundary. Studying and controlling this motion can reveal details about the microscopic processes that govern a vast array of light-matter interaction physics and applications. These include research areas right at the forefront of extreme laser-plasma science such as laser-driven ion acceleration1, bright attosecond pulse generation2,3 and efficient energy coupling for the generation and study of warm dense matter4. Here we demonstrate attosecond control over the trajectories of relativistic electron bunches formed during such interactions by studying the emission of extreme ultraviolet (XUV) harmonic radiation. We describe how the precise addition of a second laser beam operating at the second harmonic of the driving laser pulse can significantly transform the interaction by modifying the accelerating potential provided by the fundamental ...
Bound-Free Electron-Positron Pair Production in Relativistic Heavy-Ion Collisions
Sengul, M Y; Fritzsche, S
2009-01-01
The bound-free electron-positron pair production is considered for relativistic heavy ion collisions. In particular, cross sections are calculated for the pair production with the simultaneous capture of the electron into the 1s ground state of one of the ions and for energies that are relevant for the Relativistic Heavy Ion Collider (RHIC) and the Large Hadron Colliders (LHC). In the framework of perturbation theory, we applied Monte-Carlo integration techniques to compute the lowest-order Feynman diagrams amplitudes by using Darwin wave functions for the bound states of the elec- trons and Sommerfeld-Maue wave functions for the continuum states of the positrons. Calculations were performed especially for the collision of Au + Au at 100 GeV/nucleon and Pb + Pb at 3400 GeV/nucleon.
Li, Shucai; Wang, Lu; Chen, Zhongyong; Huang, Duwei; Tong, Ruihai
2016-10-01
The dynamics of relativistic electrons are analyzed using the relativistic Fokker-Planck equation including deceleration due to synchrotron radiation (SR) and radial diffusion loss caused by magnetic fluctuation (MF). Threshold electric field for avalanche growth is enhanced, and the growth rate is reduced by the combined effect of MF and SR as compared to the case with only SR. The threshold electric field is determined by the time scales balance between momentum evolution and radial diffusion loss induced by MF, and increased with level of MF. More importantly, the hysteresis behavior of runaway pointed out by does not exist anymore. This is because the ``seed electrons'' cannot be sustained as a result of diffusion loss. This work was supported by NSFC Grant No. 11305071, and the Ministry of Science and technology of China, under Contract Nos. 2013GB112002, 2015GB111002 and 2015GB111001.
On coherent radiation by relativistic electrons in ultrathin crystals
Shul' ga, N.F., E-mail: shulga@kipt.kharkov.ua [National Science Center “Kharkov Institute of Physics and Technology”, 1, Akademicheskaya str., Kharkov 61108 (Ukraine); Karazin Kharkov National University, 31, Kurchatov ave., Kharkov 61108 (Ukraine); Shul' ga, S.N. [National Science Center “Kharkov Institute of Physics and Technology”, 1, Akademicheskaya str., Kharkov 61108 (Ukraine); Karazin Kharkov National University, 31, Kurchatov ave., Kharkov 61108 (Ukraine)
2014-08-22
A quantitative theory of the radiation process by ultrarelativistic electrons in ultrathin crystals is proposed. The theory is based upon the factorization theorem of the radiation cross-section and upon the description of the scattering process on the basis of the eikonal approximation of quantum electrodynamics. The conditions are obtained, under which the effect of radiation suppression in ultrathin crystals must take place. It is shown that these conditions may be fulfilled at the interaction of electrons with the energy accessible on CERN accelerator with ultrathin silicon crystals. Since the last years one can produce such crystals for the experiments in high energy physics. This opens new possibilities in study of interaction of high energy particles with matter.
Ardaneh, Kazem; Cai, Dongsheng; Nishikawa, Ken-Ichi
2016-08-01
The course of non-thermal electron ejection in relativistic unmagnetized electron-ion shocks is investigated by performing self-consistent particle-in-cell simulations. The shocks are excited through the injection of a relativistic jet into ambient plasma, leading to two distinct shocks (referred to as the trailing shock and leading shock) and a contact discontinuity. The Weibel-like instabilities heat the electrons up to approximately half of the ion kinetic energy. The double layers formed in the trailing and leading edges then accelerate the electrons up to the ion kinetic energy. The electron distribution function in the leading edge shows a clear, non-thermal power-law tail which contains ˜1% of electrons and ˜8% of the electron energy. Its power-law index is -2.6. The acceleration efficiency is ˜23% by number and ˜50% by energy, and the power-law index is -1.8 for the electron distribution function in the trailing edge. The effect of the dimensionality is examined by comparing the results of three-dimensional simulations with those of two-dimensional simulations. The comparison demonstrates that electron acceleration is more efficient in two dimensions.
Kemp, Gregory Elijah [The Ohio State Univ., Columbus, OH (United States)
2013-01-01
Ultra-intense laser (> 1018 W/cm2) interactions with matter are capable of producing relativistic electrons which have a variety of applications in state-of-the-art scientific and medical research conducted at universities and national laboratories across the world. Control of various aspects of these hot-electron distributions is highly desired to optimize a particular outcome. Hot-electron generation in low-contrast interactions, where significant amounts of under-dense pre-plasma are present, can be plagued by highly non-linear relativistic laser-plasma instabilities and quasi-static magnetic field generation, often resulting in less than desirable and predictable electron source characteristics. High-contrast interactions offer more controlled interactions but often at the cost of overall lower coupling and increased sensitivity to initial target conditions. An experiment studying the differences in hot-electron generation between high and low-contrast pulse interactions with solid density targets was performed on the Titan laser platform at the Jupiter Laser Facility at Lawrence Livermore National Laboratory in Livermore, CA. To date, these hot-electrons generated in the laboratory are not directly observable at the source of the interaction. Instead, indirect studies are performed using state-of-the-art simulations, constrained by the various experimental measurements. These measurements, more-often-than-not, rely on secondary processes generated by the transport of these electrons through the solid density materials which can susceptible to a variety instabilities and target material/geometry effects. Although often neglected in these types of studies, the specularly reflected light can provide invaluable insight as it is directly influenced by the interaction. In this thesis, I address the use of (personally obtained) experimental specular reflectivity measurements to indirectly study hot-electron generation in the context of high-contrast, relativistic
Relativistic electrons high doses at International Space Station and Foton M2/M3 satellites
Dachev, T. P.; Tomov, B.; Matviichuk, Yu.; Dimitrov, Pl.; Bankov, N.
2009-12-01
The paper presents observation of relativistic electrons. Data are collected by the Radiation Risk Radiometer-Dosimeters (R3D) B2/B3 modifications during the flights of Foton M2/M3 satellites in 2005 and 2007 as well as by the R3DE instrument at the European Technology Exposure Facility (EuTEF) on the Columbus External Payload Adaptor at the International Space Station (ISS) in the period February 20 - April 28, 2008. On the Foton M2/M3 satellites relativistic electrons are observed more frequently than on the ISS because of higher (62.8°) inclination of the orbit. At both Foton satellites the usual duration of the observations are a few minutes long. On the ISS the duration usually is about 1 min or less. The places of observations of high doses due to relativistic electrons are distributed mainly at latitudes above 50° geographic latitude in both hemispheres on Foton M2/M3 satellites. A very high maximum is found in the southern hemisphere at longitudinal range 0°-60°E. At the ISS the maximums are observed between 45° and 52° geographic latitude in both hemispheres mainly at longitudes equatorward from the magnetic poles. The measured absolute maximums of dose rates generated by relativistic electrons are found to be as follows: 304 μGy h -1 behind 1.75 g cm -2 shielding at Foton M2, 2314 μGy h -1 behind 0.71 g cm -2 shielding at Foton M3 and 19,195 μGy h -1 (Flux is 8363 cm -2 s -1) behind les than 0.4 g cm -2 shielding at ISS.
Self-Guiding of Electromagnetic Beams in Degenerate Relativistic Electron-Positron Plasma
Berezhiani, V I
2016-01-01
The possibility of self-trapped propagation of electromagnetic beams in the fully degenerate relativistic electron-positron plasma has been studied applying Fluid-Maxwell model; it is shown that dynamics of such beams can be described by the generalized Nonlinear Schr\\"odinger equation with specific type of saturating nonlinearity. Existence of radially symmetric localized solitary structures is demonstrated. It is found that stable solitary structures exist for the arbitrary level of degeneracy.
Noureen, S.; Abbas, G.; Farooq, H.
2017-09-01
Using Vlasov-Maxwell's equations, the spectra of the perpendicular propagating Bernstein wave and Extraordinary wave in ultra-relativistic fully degenerate electron plasma are studied. The equilibrium particle distribution function is assumed to be isotropic Fermian. The analysis of high frequency spectra of the waves is carried out in the weak propagation limit Ω≫k .v and in the weak magnetic field limit |ω-k .v | ≫Ω and graphically observed.
Coherent keV backscattering from plasma-wave boosted relativistic electron mirrors
Li, F Y; Chen, M; Wu, H C; Liu, Y; Meyer-ter-Vehn, J; Mori, W B; Zhang, J
2014-01-01
A new parameter regime of laser wakefield acceleration driven by sub-petawatt femotsecond lasers is proposed, which enables the generation of relativistic electron mirrors further accelerated by the plasma wave. Integrated particle-in-cell simulation including the mirror formation and Thomson scattering demonstrates that efficient coherent backscattering up to keV photon energy can be obtained with moderate driver laser intensities and high density gas targets.
Relativistic electrons and magnetic field of the M87 jet on ~ten Schwarzschild radii scale
Kino, M; Hada, K; Doi, A
2014-01-01
We explore energy densities of magnetic field and relativistic electrons in the M87 jet. Since the radio core at the jet base is identical to the optically thick surface against synchrotron self absorption (SSA), the observing frequency is identical to the SSA turnover frequency. As a first step, we assume the radio core as a simple uniform sphere geometry. Using the observed angular size of the radio core measured by the Very Long Baseline Array at 43 GHz, we estimate the energy densities of magnetic field ($U_{B}$) and relativistic electrons ($U_{e}$) based on the standard SSA formula. Imposing the condition that the Poynting power and relativistic electron one should be smaller than the total power of the jet, we find that (i) the allowed range of the magnetic field strength ($B_{tot}$) is from 1 G to 15 G, and that (ii) $1 times 10^{-5} < U_{e}/U_{B} < 6 times 10^{2}$ holds. The uncertainty of $U_{e}/U_{B}$ comes from the strong dependence on the angular size of the radio core and the minimum Lorent...
Laser-Assisted Semi Relativistic Excitation of Atomic Hydrogen by Electronic Impact
Taj, S; Idrissi, M El; Oufni, L
2012-01-01
The excitation of H ($1s-2s$) by electron impact in the presence and in the absence of the laser field is studied in the framework of the first Born approximation. The angular variation of the laser-assisted differential cross section (DCS) for atomic hydrogen by electronic impact is presented at various kinetic energies for the incident electron. The use of Darwin wave function as a semirelativistic state to represent the atomic hydrogen gives interesting results when the condition $z/c\\ll1$ is fulfilled. A comparison with the non relativistic theory and experimental data gives good agreement. It was observed that beyond (2700 $eV$) which represents the limit between the two approaches, the non relativistic theory does not yield close agreement with our theory and that, over certain ranges of energy, it can be in error by several orders of magnitude. The sum rule given by Bunkin and Fedorov and by Kroll and Watson \\cite{22} has been verified in both nonrelativistic and relativistic regimes.
Laser-driven micro-Coulomb charge movement and energy conversion to relativistic electrons
Cobble, J. A.; Palaniyappan, S.; Johnson, R. P.; Shimada, T.; Huang, C.; Gautier, D. C.; Clark, D. D.; Falk, K.; Jung, D.
2016-09-01
Development of robust instrumentation has shown evidence for a multi-μC expulsion of relativistic electrons from a sub-μm-thick foil, laser illuminated with 60-70 J on target at 2 × 1020 W/cm2. From previous work and with electron spectroscopy, it is seen that an exponential electron energy distribution is accurate enough to calculate the emitted electron charge and energy content. The 5-10-μC charge for the >100-TW Trident Laser represents the first active measurement of the >50% laser-light-to-electron conversion efficiency. By shorting out the TV/m electric field usually associated with accelerating multi-MeV ions from such targets, one finds that this charge is representative of a multi-MA current of relativistic electrons for diverse applications from electron fast ignition to advanced radiography concepts. Included with the details of the discoveries of this research, shortcomings of the diagnostics and means of improving their fidelity are discussed.
Modeling the relativistic runaway electron avalanche and the feedback mechanism with GEANT4
Skeltved, Alexander Broberg; Carlson, Brant; Gjesteland, Thomas; Celestin, Sebastien
2016-01-01
This paper presents the first study that uses the GEometry ANd Tracking 4 (GEANT4) toolkit to do quantitative comparisons with other modelling results related to the production of Terrestrial Gamma-ray Flashes (TGFs) and high-energy particle emission from thunderstorms. We will study the Relativistic Runaway Electron Avalanche (RREA) and the relativistic feedback process, as well as the production of bremsstrahlung photons from Runaway Electrons (REs). The Monte Carlo (MC) simulations take into account the effects of electron ionisation, electron by electron (M{\\o}ller) and electron by positron (Bhabha) scattering as well as the bremsstrahlung process and pair-production, in the $250$ eV$-100$ GeV energy range. Our results indicate that the multiplication of electrons during the development of RREAs and under the influence of feedback, are consistent with previous estimates. This is important to validate GEANT4 as a tool to model RREAs and feedback in homogeneous electric fields. We also determine the ratio o...
Baryons in the relativistic jets of the stellar-mass black-hole candidate 4U 1630-47.
Trigo, María Díaz; Miller-Jones, James C A; Migliari, Simone; Broderick, Jess W; Tzioumis, Tasso
2013-12-12
Accreting black holes are known to power relativistic jets, both in stellar-mass binary systems and at the centres of galaxies. The power carried away by the jets, and, hence, the feedback they provide to their surroundings, depends strongly on their composition. Jets containing a baryonic component should carry significantly more energy than electron-positron jets. Energetic considerations and circular-polarization measurements have provided conflicting circumstantial evidence for the presence or absence of baryons in jets, and the only system in which they have been unequivocally detected is the peculiar X-ray binary SS 433 (refs 4, 5). Here we report the detection of Doppler-shifted X-ray emission lines from a more typical black-hole candidate X-ray binary, 4U 1630-47, coincident with the reappearance of radio emission from the jets of the source. We argue that these lines arise from baryonic matter in a jet travelling at approximately two-thirds the speed of light, thereby establishing the presence of baryons in the jet. Such baryonic jets are more likely to be powered by the accretion disk than by the spin of the black hole, and if the baryons can be accelerated to relativistic speeds, the jets should be strong sources of γ-rays and neutrino emission.
Ardaneh, Kazem; Nishikawa, Ken-Ichi
2016-01-01
The course of non-thermal electron ejection in relativistic unmagnetized electron-ion shocks is investigated by performing self-consistent particle-in-cell simulations. The shocks are excited through the injection of relativistic jet into ambient plasma, leading to two distinct shocks (named as the trailing shock and leading shock) and a contact discontinuity. The Weibel-like instabilities heat the electrons up to approximately half of ion kinetic energy. The double layers formed in the trailing and leading edges then accelerated the electrons by the ion kinetic energy. The electron distribution function in the leading edge shows a clear non-thermal power-law tail which contains $\\sim1\\%$ of electrons and $\\sim8\\%$ of electron energy. Its power-law index is -2.6. The acceleration efficiency is $\\sim23\\%$ by number and $\\sim50\\%$ by energy and the power-law index is -1.8 for electron distribution function in the trailing edge. The effect of the dimensionality is examined by comparing results of 3D simulation w...
Sahu, Biswajit, E-mail: biswajit-sahu@yahoo.co.in [Department of Mathematics, West Bengal State University, Barasat, Kolkata 700126 (India); Sinha, Anjana, E-mail: sinha.anjana@gmail.com [Department of Instrumentation Science, Jadavpur University, Kolkata 700 032 (India); Roychoudhury, Rajkumar, E-mail: rroychoudhury123@gmail.com [Department of Mathematics, Visva-Bharati, Santiniketan - 731 204, India and Advanced Centre for Nonlinear and Complex Phenomena, 1175 Survey Park, Kolkata 700 075 (India)
2015-09-15
A numerical study is presented of the nonlinear dynamics of a magnetized, cold, non-relativistic plasma, in the presence of electron-ion collisions. The ions are considered to be immobile while the electrons move with non-relativistic velocities. The primary interest is to study the effects of the collision parameter, external magnetic field strength, and the initial electromagnetic polarization on the evolution of the plasma system.
Relativistic electron vortex beams in a laser field
Bandyopadhyay, Pratul; Chowdhury, Debashree
2015-01-01
The orbital angular momentum Hall effect and spin Hall effect of electron vortex beams (EVB) have been studied for the EVBs interacting with laser field. In the scenario of paraxial beam, the cumulative effect of the orbit-orbit interaction of EVBs and laser fields drives the orbital Hall effect, which in turn produces a shift of the center of the beam from that of the field-free case towards the polarization axis of photons. Besides, for non-paraxial beams one can also perceive a similar shift of the center of the beam owing to spin Hall effect involving spin-orbit interaction. Our analysis suggests that the shift in the paraxial beams will always be larger than that in non-paraxial beams.
Dielectric laser acceleration of non-relativistic electrons at a photonic structure
Breuer, John
2013-08-29
This thesis reports on the observation of dielectric laser acceleration of non-relativistic electrons via the inverse Smith-Purcell effect in the optical regime. Evanescent modes in the vicinity of a periodic grating structure can travel at the same velocity as the electrons along the grating surface. A longitudinal electric field component is used to continuously impart momentum onto the electrons. This is only possible in the near-field of a suitable photonic structure, which means that the electron beam has to pass the structure within about one wavelength. In our experiment we exploit the third spatial harmonic of a single fused silica grating excited by laser pulses derived from a Titanium:sapphire oscillator and accelerate non-relativistic 28 keV electrons. We measure a maximum energy gain of 280 eV, corresponding to an acceleration gradient of 25 MeV/m, already comparable with state-of-the-art radio-frequency linear accelerators. To experience this acceleration gradient the electrons approach the grating closer than 100 nm. We present the theory behind grating-based particle acceleration and discuss simulation results of dielectric laser acceleration in the near-field of photonic grating structures, which is excited by near-infrared laser light. Our measurements show excellent agreement with our simulation results and therefore confirm the direct acceleration with the light field. We further discuss the acceleration inside double grating structures, dephasing effects of non-relativistic electrons as well as the space charge effect, which can limit the attainable peak currents of these novel accelerator structures. The photonic structures described in this work can be readily concatenated and therefore represent a scalable realization of dielectric laser acceleration. Furthermore, our structures are directly compatible with the microstructures used for the acceleration of relativistic electrons demonstrated in parallel to this work by our collaborators in
Madokoro, Hideki; Matsuzaki, Masayuki
1997-01-01
Relativistic Mean Field Theory is applied to the description of rotating nuclei. Since the previous formulation of Munich group was based on a special relativistic transformation property of the spinor fields, we reformulate in a fully covariant manner using tetrad formalism. The numerical calculations are performed for 3 zinc isotopes, including the newly discovered superdeformed band in $^{62}$Zn which is the first experimental observation in this mass region.
Madokoro, H.; Matsuzaki, M.
Relativistic Mean Field Theory is applied to the description of rotating nuclei. Since the previous formulation of Munich group was based on a special relativistic transformation property of the spinor fields, we reformulate in a fully covariant manner using tetrad formalism. The numerical calculations are performed for 3 zinc isotopes, including the newly discovered superdeformed band in $^{62}$Zn which is the first experimental observation in this mass region.
Evidence for acceleration of outer zone electrons to relativistic energies by whistler mode chorus
N. P. Meredith
Full Text Available We use plasma wave and electron data from the Combined Release and Radiation Effects Satellite (CRRES to investigate the viability of a local stochastic electron acceleration mechanism to relativistic energies driven by gyroresonant interactions with whistler mode chorus. In particular, we examine the temporal evolution of the spectral response of the electrons and the waves during the 9 October 1990 geomagnetic storm. The observed hardening of the electron energy spectra over about 3 days in the recovery phase is coincident with prolonged substorm activity, as monitored by the AE index and enhanced levels of whistler mode chorus waves. The observed spectral hardening is observed to take place over a range of energies appropriate to the resonant energies associated with Doppler-shifted cyclotron resonance, as supported by the construction of realistic resonance curves and resonant diffusion surfaces. Furthermore, we show that the observed spectral hardening is not consistent with energy-independent radial diffusion models. These results provide strong circumstantial evidence for a local stochastic acceleration mechanism, involving the energisation of a seed population of electrons with energies of the order of a few hundred keV to relativistic energies, driven by wave-particle interactions involving whistler mode chorus. The results suggest that this mechanism contributes to the reformation of the relativistic outer zone population during geomagnetic storms, and is most effective when the recovery phase is characterised by prolonged substorm activity. An additional significant result of this paper is that we demonstrate that the lower energy part of the storm-time electron distribution is in steady-state balance, in accordance with the Kennel and Petschek (1966 theory of limited stably-trapped particle fluxes.
Key words. Magnetospheric physics (storms and substorms, energetic particles, trapped – Space plasma physics (wave
Re-hardening of hadron transverse mass spectra in relativistic heavy-ion collisions
P K Sahu; N Otuka; M Isse; Y Nara; A Ohnishi
2006-05-01
We analyze the spectra of pions and protons in heavy-ion collisions at relativistic energies from 2 A GeV to 65+65 A GeV by using a jet-implemented hadron-string cascade model. In this energy region, hadron transverse mass spectra first show softening until SPS energies, and re-hardening may emerge at RHIC energies. Since hadronic matter is expected to show only softening at higher energy densities, this re-hardening of spectra can be interpreted as a good signature of the quark-gluon plasma formation.
Electron Capture in 163Ho and Overlap plus Exchange Corrections and the Neutrino Mass
Faessler, Amand; Simkovic, M F
2014-01-01
Holmium offers perhaps the best chance to determine the neutrino mass by electron capture. This contribution treats the electron capture in 163Holmium completely relativistic for the overlap and exchange corrections. The theoretical expressions are derived consistently in second quantisation with the help of Wick's theorem assuming single Slater determinants for the initial Ho and the final Dy atoms with holes in the final ns1/2 and np1/2 states. No hand waving arguments are needed to derive the exchange terms. It seems, that for the first time the multiplicity of electrons in the orbital overlaps are included in the numerical treatment. Electron capture e + p --> n + neutrino is proportional to the probability to find the captured electron in the parent atom at the nucleus. Non-relativistically this is only possible for ns1/2 electron states. Relativistically also p1/2 electrons have a probability to be at the nucleus due to the lower part of the relativistic electron spinor, which does not disappear at the ...
Estimation of mass outflow rates from viscous relativistic accretion discs around black holes
Chattopadhyay, Indranil; Kumar, Rajiv
2016-07-01
We investigated flow in Schwarzschild metric, around a non-rotating black hole and obtained self-consistent accretion-ejection solution in full general relativity. We covered the whole of parameter space in the advective regime to obtain shocked, as well as, shock-free accretion solution. We computed the jet streamline using von Zeipel surfaces and projected the jet equations of motion on to the streamline and solved them simultaneously with the accretion disc equations of motion. We found that steady shock cannot exist beyond α ≳ 0.06 in the general relativistic prescription, but is lower if mass-loss is considered too. We showed that for fixed outer boundary, the shock moves closer to the horizon with increasing viscosity parameter. The mass outflow rate increases as the shock moves closer to the black hole, but eventually decreases, maximizing at some intermediate value of shock location. The jet terminal speed increases with stronger shocks; quantitatively speaking, the terminal speed of jets vj∞ > 0.1 if rsh < 20rg. The maximum of the outflow rate obtained in the general relativistic regime is less than 6 per cent of the mass accretion rate.
Andonian, G; Barber, S; O'Shea, F H; Fedurin, M; Kusche, K; Swinson, C; Rosenzweig, J B
2017-02-03
Temporal pulse tailoring of charged-particle beams is essential to optimize efficiency in collinear wakefield acceleration schemes. In this Letter, we demonstrate a novel phase space manipulation method that employs a beam wakefield interaction in a dielectric structure, followed by bunch compression in a permanent magnet chicane, to longitudinally tailor the pulse shape of an electron beam. This compact, passive, approach was used to generate a nearly linearly ramped current profile in a relativistic electron beam experiment carried out at the Brookhaven National Laboratory Accelerator Test Facility. Here, we report on these experimental results including beam and wakefield diagnostics and pulse profile reconstruction techniques.
The Diagnostics Of Hydrogen-Cesium Plasma Using Fully Relativistic Electron Impact Cross Sections
Priti, Priti; Dipti, Dipti; Gangwar, Reetesh; Srivastava, Rajesh
2016-10-01
Electron excitation cross-sections and rate coefficients have been calculated using fully relativistic distorted wave theory for several fine-structure transitions from the ground as well as excited states of cesium atom in the wide range of incident electron energy. These processes play dominant role in low pressure hydrogen-cesium plasma relevant to the negative ion based neutral beam injectors for the ITER project. The calculated cross-sections are used to construct a reliable collisional radiative (CR) model to characterize the hydrogen-cesium plasma. The calculated plasma parameters are compared with the available experimental and theoretical results.
High efficiency energy extraction from a relativistic electron beam in a strongly tapered undulator
Sudar, Nicholas; Duris, Joe; Gadjev, Ivan; Polyaniy, Mikhail; Pogorelsky, Igor; Fedurin, Mikhail; Swinson, Christina; Babzien, Marcus; Kusche, Karl; Gover, Avi
2016-01-01
We present results of an experiment where, using a 200 GW CO2 laser seed, a 65 MeV electron beam was decelerated down to 35 MeV in a 54 cm long strongly tapered helical magnetic undulator, extracting over 30$\\%$ of the initial electron beam energy to coherent radiation. These results demonstrate unparalleled electro-optical conversion efficiencies for a relativistic beam in an undulator field and represent an important step in the development of high peak and average power coherent radiation sources.
Andonian, G.; Barber, S.; O'Shea, F. H.; Fedurin, M.; Kusche, K.; Swinson, C.; Rosenzweig, J. B.
2017-02-01
Temporal pulse tailoring of charged-particle beams is essential to optimize efficiency in collinear wakefield acceleration schemes. In this Letter, we demonstrate a novel phase space manipulation method that employs a beam wakefield interaction in a dielectric structure, followed by bunch compression in a permanent magnet chicane, to longitudinally tailor the pulse shape of an electron beam. This compact, passive, approach was used to generate a nearly linearly ramped current profile in a relativistic electron beam experiment carried out at the Brookhaven National Laboratory Accelerator Test Facility. Here, we report on these experimental results including beam and wakefield diagnostics and pulse profile reconstruction techniques.
High Efficiency Energy Extraction from a Relativistic Electron Beam in a Strongly Tapered Undulator
Sudar, N.; Musumeci, P.; Duris, J.; Gadjev, I.; Polyanskiy, M.; Pogorelsky, I.; Fedurin, M.; Swinson, C.; Kusche, K.; Babzien, M.; Gover, A.
2016-10-01
We present results of an experiment where, using a 200 GW CO2 laser seed, a 65 MeV electron beam was decelerated down to 35 MeV in a 54-cm-long strongly tapered helical magnetic undulator, extracting over 30% of the initial electron beam energy to coherent radiation. These results, supported by simulations of the radiation field evolution, demonstrate unparalleled electro-optical conversion efficiencies for a relativistic beam in an undulator field and represent an important step in the development of high peak and average power coherent radiation sources.
All-optical time-resolved measurement of laser energy modulation in a relativistic electron beam
D. Xiang
2011-11-01
Full Text Available We propose and demonstrate an all-optical method to measure laser energy modulation in a relativistic electron beam. In this scheme the time-dependent energy modulation generated from the electron-laser interaction in an undulator is converted into time-dependent density modulation with a chicane, which is measured to infer the laser energy modulation. The method, in principle, is capable of simultaneously providing information on femtosecond time scale and 10^{-5} energy scale not accessible with conventional methods. We anticipate that this method may have wide applications in many laser-based advanced beam manipulation techniques.
Nonlinear reflection of high-amplitude laser pulses from relativistic electron mirrors
Kulagin, V. V.; Kornienko, V. N.; Cherepenin, V. A.
2016-04-01
A coherent X-ray pulse of attosecond duration can be formed in the reflection of a counterpropagating laser pulse from a relativistic electron mirror. The reflection of a high-amplitude laser pulse from the relativistic electron mirror located in the field of an accelerating laser pulse is investigated by means of two-dimensional (2D) numerical simulation. It is shown that provided the amplitude of the counterpropagating laser pulse is several times greater than the amplitude of the accelerating laser pulse, the reflection process is highly nonlinear, which causes a significant change in the X-ray pulse shape and its shortening up to generation of quasi-unipolar pulses and single-cycle pulses. A physical mechanism responsible for this nonlinearity of the reflection process is explained, and the parameters of the reflected X-ray pulses are determined. It is shown that the duration of these pulses may constitute 50 - 60 as, while their amplitude may be sub-relativistic.
Shukla, Chandrasekhar; Das, Amita; Patel, Kartik
2016-08-01
We carry out particle-in-cell simulations to study the instabilities associated with a 2-D sheared electron flow configuration against a neutralizing background of ions. Both weak and strong relativistic flow velocities are considered. In the weakly relativistic case, we observe the development of electromagnetic Kelvin-Helmholtz instability with similar characteristics as that predicted by the electron Magnetohydrodynamic (EMHD) model. On the contrary, in a strong relativistic case, the compressibility effects of electron fluid dominate and introduce upper hybrid electrostatic oscillations transverse to the flow which are very distinct from EMHD fluid behavior. In the nonlinear regime, both weak and strong relativistic cases lead to turbulence with broad power law spectrum.
Cosmological Constraints on a Dynamical Electron Mass
Barrow, J D; Barrow, John D; Magueijo, Joao
2005-01-01
Motivated by recent astrophysical observations of quasar absorption systems, we formulate a simple theory where the electron to proton mass ratio $\\mu =m_{e}/m_{p}$ is allowed to vary in space-time. In such a minimal theory only the electron mass varies, with $\\alpha $ and $m_{p}$ kept constant. We find that changes will be driven by any asymmetry in the electron-positron number density after the electron mass threshold is crossed. Particle production in this scenario is negligible. The constraints imposed by recent observations are very weak, due to the low mass density in electrons.
The relativistic electron plasma: a candidate for nature's left-handed material
de Carvalho, C A A
2015-01-01
The electric permittivities and magnetic permeabilities for a relativistic electron gas are calculated from quantum electrodynamics at finite temperature and density as functions of temperature, chemical potential, frequency, and wavevector. The polarization and the magnetization depend linearly on both electric and magnetic fields, and are the sum of a zero-temperature and zero-density vacuum part with a temperature- and chemical potential-dependent medium part. Analytic calculations lead to generalized expressions that depend on three scalar functions. In the nonrelativistic limit, results reproduce the Lindhard formula. In the relativistic case, and in the long wavelength limit, we obtain: i) for $\\omega=0$, generalized susceptibilities that reduce to known nonrelativistic limits; ii) for $\\omega \
Propagation of Ordinary and Extraordinary Modes in Ultra-Relativistic Maxwellian Electron Plasma
Ali, M.; Zaheer, S.; Murtaza, G.
2010-12-01
Modes of ultra relativistic electron plasma embedded in a strong magnetic field are investigated for perpendicular propagation. Using Boltzmann-Vlasov equation, a general expression for the conductivity tensor is derived. An ultra-relativistic Maxwellian distribution function is employed to derive different modes for strong magnetic field limit. In particular, the dispersion relations for the ordinary mode and the extra ordinary mode (O-mode and X-mode) are obtained. Graphs of these dispersion relations and the imaginary parts of the frequency are drawn for some specific values of the parameters. It is observed that the damping rate increases gradually, reaches some maximum point and then decreases for larger wavenumbers. Further, increasing the strength of the magnetic field lowers the maximum value of the damping rate.
Brunetti, G
2016-01-01
In this paper we investigate a situation where relativistic particles are reaccelerated diffusing across regions of reconnection and magnetic dynamo in super-Alfvenic, incompressible large-scale turbulence. We present an exploratory study of this mechanism in the intra-cluster-medium (ICM). In view of large-scale turbulence in the ICM we adopt a reconnection scheme that is based on turbulent reconnection and MHD turbulence. In this case particles are accelerated and decelerated in a systematic way in reconnecting and magnetic-dynamo regions, respectively, and on longer time-scales undergo a stochastic process diffusing across these sites (similar to second-order Fermi). Our study extends on larger scales numerical studies that focused on the acceleration in and around turbulent reconnecting regions. We suggest that this mechanism may play a role in the reacceleration of relativistic electrons in galaxy clusters providing a new physical scenario to explain the origin of cluster-scale diffuse radio emission. In...
González-Jiménez, R; Donnelly, T W
2015-01-01
We study parity violation in quasielastic (QE) electron-nucleus scattering using the relativistic impulse approximation. Different fully relativistic approaches have been considered to estimate the effects associated with the final-state interactions. We have computed the parity-violating quasielastic (PVQE) asymmetry and have analyzed its sensitivity to the different ingredients that enter in the description of the reaction mechanism: final-state interactions, nucleon off-shellness effects, current gauge ambiguities. Particular attention has been paid to the description of the weak neutral current form factors. The PVQE asymmetry is proven to be an excellent observable when the goal is to get precise information on the axial-vector sector of the weak neutral current. Specifically, from measurements of the asymmetry at backward scattering angles good knowledge of the radiative corrections entering in the isovector axial-vector sector can be gained. Finally, scaling properties shown by the interference $\\gamma...
Propagation of ion-acoustic solitary waves in a relativistic electron-positron-ion plasma
Saberian, E; Akbari-Moghanjoughi, M
2011-01-01
Propagation of large amplitude ion-acoustic solitary waves (IASWs) in a fully relativistic plasma consisting of cold ions and ultrarelativistic hot electrons and positrons is investigated using the Sagdeev's pseudopotential method in a relativistic hydrodynamics model. Effects of streaming speed of plasma fluid, thermal energy, positron density and positron temperature on large amplitude IASWs are studied by analysis of the pseudopotential structure. It is found that in regions that the streaming speed of plasma fluid is larger than that of solitary wave, by increasing the streaming speed of plasma fluid the depth and width of potential well increases and resulting in narrower solitons with larger amplitude. This behavior is opposite for the case where the streaming speed of plasma fluid is smaller than that of solitary wave. On the other hand, increase of the thermal energy results in wider solitons with smaller amplitude, because the depth and width of potential well decreases in that case. Additionally, th...
Christiansen, P.A.; Pitzer, K.S.
1980-07-01
The dissociation curve for the ground state of TlH was computed using a relativistic {omega}-{omega} coupling formalism. The relativistic effects represented by the Dirac equation were introduced using effective potentials generated from atomic Dirac-Fock wave functions using a generalization of the improved effective potential formulation of Christiansen, Lee, and Pitzer. The multiconfiguration SCF treatment used is a generalization of the two-component molecular spinor formalism of Lee, Ermler, and Pitzer. Using a five configuration wave function we were able to obtain approximately 85% of the experimental dissociation energy. Our computations indicate that the bond is principally sigma in form, despite the large spin-orbit splitting in atomic thallium. Furthermore the bond appears to be slightly ionic (Tl{sup +}H{sup -}) with about 0.3 extra electron charge on the hydrogen.
Arefiev, A V; Robinson, A P L; Shvets, G; Willingale, L; Schollmeier, M
2016-01-01
We examine a regime in which a linearly-polarized laser pulse with relativistic intensity irradiates a sub-critical plasma for much longer than the characteristic electron response time. A steady-state channel is formed in the plasma in this case with quasi-static transverse and longitudinal electric fields. These relatively weak fields significantly alter the electron dynamics. The longitudinal electric field reduces the longitudinal dephasing between the electron and the wave, leading to an enhancement of the electron energy gain from the pulse. The energy gain in this regime is ultimately limited by the superluminosity of the wave fronts induced by the plasma in the channel. The transverse electric field alters the oscillations of the transverse electron velocity, allowing it to remain anti-parallel to laser electric field and leading to a significant energy gain. The energy enhancement is accompanied by development of significant oscillations perpendicular to the plane of the driven motion, making traject...
High-repetition rate relativistic electron beam generation from intense laser solid interactions
Batson, Thomas; Nees, John; Hou, Bixue; Thomas, A. G. R.; Krushelnick, Karl
2015-05-01
Relativistic electron beams have applications spanning materials science, medicine, and home- land security. Recent advances in short pulse laser technology have enabled the production of very high focused intensities at kHz rep rates. Consequently this has led to the generation of high ux sources of relativistic electrons- which is a necessary characteristic of these laser plasma sources for any potential application. In our experiments, through the generation of a plasma with the lambda cubed laser system at the University of Michigan (a 5 × 1018W=cm2, 500 Hz, Ti:Sapphire laser), we have measured electrons ejected from the surface of fused silica nd Cu targets having energies in excess of an MeV. The spectrum of these electrons was measured with respect to incident laser angle, prepulse timing, and focusing conditions. While taken at a high repetition rate, the pulse energy of the lambda cubed system was consistently on the order of 10 mJ. In order to predict scaling of the electron energy with laser pulse energy, simulations are underway which compare the spectrum generated with the lambda cubed system to the predicted spectrum generated on the petawatt scale HERCULES laser system at the University of Michigan.
The Earth's Electron Radiation Belts Modeling: from the Source Population to Relativistic Energies
Aseev, N.; Shprits, Y. Y.; Kellerman, A. C.; Drozdov, A.; Zhu, H.
2016-12-01
The dynamics of the Earth's electron radiation belts is characterized by intricate interactions of different particle populations. During the main phase of a geomagnetic storm, electron source (tens keV) and seed (hundreds keV) populations are injected from the plasma sheet to the outer belt region. The source population transfers energy to electromagnetic waves, while the seed population can be accelerated locally by interaction with chorus waves. Electrons can also be lost by scattering into the loss cone due to wave-particle interaction and by magnetopause shadowing due to outward radial motion. In this work, we present results of simulations of the dynamics of electron fluxes in the inner magnetosphere from a few keV to relativistic energies of several MeV using the VERB-4D code. The code includes radial, energy and pitch angle diffusion, convection and adiabatic effects due to compression or expansion of the magnetic field. We extended the spatial outer boundary of the computational domain to 10-15 RE which allow us to study, how the source and seed population particles are convected from the plasma sheet, accelerated to relativistic energies and lost to the atmosphere or the magnetopause. The results of simulations reproduce Van Allen Probes, GOES and THEMIS observations, indicating that magnetospheric convection is the main driver of electron dynamics above the GEO, while radial diffusion and local diffusion are the most important processes in the outer belt region.
Modeling the relativistic runaway electron avalanche and the feedback mechanism with GEANT4
Skeltved, Alexander Broberg; Østgaard, Nikolai; Carlson, Brant; Gjesteland, Thomas; Celestin, Sebastien
2014-01-01
This paper presents the first study that uses the GEometry ANd Tracking 4 (GEANT4) toolkit to do quantitative comparisons with other modeling results related to the production of terrestrial gamma ray flashes and high-energy particle emission from thunderstorms. We will study the relativistic runaway electron avalanche (RREA) and the relativistic feedback process, as well as the production of bremsstrahlung photons from runaway electrons. The Monte Carlo simulations take into account the effects of electron ionization, electron by electron (Møller), and electron by positron (Bhabha) scattering as well as the bremsstrahlung process and pair production, in the 250 eV to 100 GeV energy range. Our results indicate that the multiplication of electrons during the development of RREAs and under the influence of feedback are consistent with previous estimates. This is important to validate GEANT4 as a tool to model RREAs and feedback in homogeneous electric fields. We also determine the ratio of bremsstrahlung photons to energetic electrons Nγ/Ne. We then show that the ratio has a dependence on the electric field, which can be expressed by the avalanche time τ(E) and the bremsstrahlung coefficient α(ε). In addition, we present comparisons of GEANT4 simulations performed with a “standard” and a “low-energy” physics list both validated in the 1 keV to 100 GeV energy range. This comparison shows that the choice of physics list used in GEANT4 simulations has a significant effect on the results. Key Points Testing the feedback mechanism with GEANT4 Validating the GEANT4 programming toolkit Study the ratio of bremsstrahlung photons to electrons at TGF source altitude PMID:26167437
Brito, T.; Hudson, M. K.; Kress, B. T.
2011-12-01
-angle scatter into the loss cone. 1Rostoker, G., et al. (1998), On the origin of relativistic electrons in the magnetosphere associated with some geomagnetic storms, Geophys. Res. Lett.,25(19), 3701 -3704. 2Millan, R.M., Thorne, R.M. (2007), Review of radiation belt relativistic electron losses, J. Atmos. Solar Terr. Phys.,69(3),362-377. 3Loto'aniu, T. M., et al. (2010), Relativistic electron loss due to ultra-low frequency waves and enhanced outward radial diffusion, J. Geophys. Res.,115(A12), A12,245. 4 Kokorowski, M., et al. (2008), Magnetospheric Electric Field Variations Caused By Storm-time Shock Front, Advances in Space Research, 42,181-191.
Single-shot divergence measurements of a laser-generated relativistic electron beam
Perez, F.; Baton, S. D.; Koenig, M.; Chen, C. D.; Hey, D.; Key, M. H.; Le Pape, S.; Ma, T.; McLean, H. S.; MacPhee, A. G.; Patel, P. K.; Ping, Y.; Beg, F. N.; Higginson, D. P.; Murphy, C. W.; Sawada, H.; Westover, B.; Yabuuchi, T.; Akli, K. U.; Giraldez, E.; Hoppe, M.; Shearer, C.; Stephens, R. B.; Gremillet, L.; Lefebvre, E.; Freeman, R. R.; Kemp, G. E.; Krygier, A. G.; Van Woerkom, L. D.; Fedosejevs, R.; Friesen, R. H.; Tsui, Y. Y.; Turnbull, D.
2010-11-01
The relativistic electron transport induced by an ultraintense picosecond laser is experimentally investigated using an x-ray two-dimensional imaging system. Previous studies of the electron beam divergence [R. B. Stephens et al. Phys. Rev. E 69, 066414 (2004), for instance] were based on an x-ray imaging of a fluorescence layer buried at different depths in the target along the propagation axis. This technique required several shots to be able to deduce the divergence of the beam. Other experiments produced single-shot images in a one-dimensional geometry. The present paper describes a new target design producing a single-shot, two-dimensional image of the electrons propagating in the target. Several characteristics of the electron beam are extracted and discussed and Monte Carlo simulations provide a good understanding of the observed beam shape. The proposed design has proven to be efficient, reliable, and promising for further similar studies.
On quantum effects in spontaneous emission by a relativistic electron beam in an undulator
Geloni, Gianluca; Saldin, Evgeni
2012-01-01
Robb and Bonifacio (2011) claimed that a previously neglected quantum effect results in noticeable changes in the evolution of the energy distribution associated with spontaneous emission in long undulators. They revisited theoretical models used to describe the emission of radiation by relativistic electrons as a continuous diffusive process, and claimed that in the asymptotic limit for a large number of undulator periods the evolution of the electron energy distribution occurs as discrete energy groups according to Poisson distribution. We show that these novel results have no physical sense, because they are based on a one-dimensional model of spontaneous emission and assume that electrons are sheets of charge. However, electrons are point-like particles and, as is well-known, the bandwidth of the angular-integrated spectrum of undulator radiation is independent of the number of undulator periods. If we determine the evolution of the energy distribution using a three-dimensional theory we find the well-kno...
Guiding of relativistic electron beams in solid targets by resistively controlled magnetic fields.
Kar, S; Robinson, A P L; Carroll, D C; Lundh, O; Markey, K; McKenna, P; Norreys, P; Zepf, M
2009-02-06
Guided transport of a relativistic electron beam in solid is achieved experimentally by exploiting the strong magnetic fields created at the interface of two metals of different electrical resistivities. This is of substantial relevance to the Fast Ignitor approach to fusion energy production [M. Tabak, Phys. Plasmas 12, 057305 (2005)10.1063/1.1871246], since it allows the electron deposition to be spatially tailored-thus adding substantial design flexibility and preventing inefficiencies due to electron beam spreading. In the experiment, optical transition radiation and thermal emission from the target rear surface provide a clear signature of the electron confinement within a high resistivity tin layer sandwiched transversely between two low resistivity aluminum slabs. The experimental data are found to agree well with numerical simulations.
CHEN Ming-Zhi; HE Jian-Hua
2009-01-01
Undulators are key devices to produce brilliant synchrotron radiation at the synchrotron radiation facilities.In this paper we present a numerical computing method,including the computing program that has been developed to calculate the spontaneous radiation emitted from relativistic electrons in undulators by simulating the electrons' trajectory.The effects of electron beam emittance and energy spread have also been taken into account.Comparing with other computing methods available at present,this method has a few advantages with respect to several aspects.It can adopt any measured or arbitrarily simulated 3D magnetic field and arbitrary electron beam pattern for the calculation and it's able to analyze undulators of any type of magnetic structure.It's expected to predict precisely the practical radiation spectrum.The calculation results of a short period in-vacuum undulator and an EllipticaUy Polarized Undulator (EPU) at Shanghai Synchrotron Radiation Facility (SSRF) are presented as examples.
QED shift calculations in relativistic many-electron atoms and ions
Tupitsyn, I I; Safronova, M S; Shabaev, V M; Dzuba, V A
2016-01-01
We incorporated quantum electrodynamics (QED) corrections into the broadly-applicable high-precision relativistic method that combines configuration interaction (CI) and linearized coupled-cluster approaches. With the addition of the QED, this CI+all-order method allows one to accurately predict properties of heavy ions of particular interest to the design of precision atomic clocks and tests of fundamental physics. To evaluate the accuracy of the QED contributions and test various QED models, we incorporated four different one-electron QED potentials. We demonstrated that all of them give consistent and reliable results. For the strongly bound electrons (i.e. inner electrons of heavy atoms, or valence electrons in highly-charged ions), the nonlocal potentials are more accurate, than the local one. Results are presented for cases of particular experimental interest.
Relativistic light-shift theory of few-electron systems: Heliumlike highly charged ions
Postavaru, O.; Scafes, A. C.
2017-09-01
The light-shift theory of many-electron systems in a laser field is described using the projection operators technique. In heavy ions, the electrons are tightly bound by the Coulomb potential of the nucleus, which prohibits ionization even by strong lasers. However, interaction with the monofrequent laser field leads to dynamic shifts of the electronic energy levels, and the process is treated by second-order time-dependent perturbation theory. In order to treat heliumlike systems, one decomposes the corresponding matrix elements into hydrogenlike matrix elements using the independent particle model. We are applying a fully relativistic description of the electronic states by means of the Dirac equation. Our formalism goes beyond the Stark long-wavelength dipole approximation and takes into account nondipole effects of retardation and interaction with the magnetic field components of the laser beam.
Kuramitsu, Y; Nakanii, N; Kondo, K; Sakawa, Y; Mori, Y; Miura, E; Tsuji, K; Kimura, K; Fukumochi, S; Kashihara, M; Tanimoto, T; Nakamura, H; Ishikura, T; Takeda, K; Tampo, M; Kodama, R; Kitagawa, Y; Mima, K; Tanaka, K A; Hoshino, M; Takabe, H
2011-02-01
Nonthermal acceleration of relativistic electrons is investigated with an intensive laser pulse. An energy distribution function of energetic particles in the universe or cosmic rays is well represented by a power-law spectrum, therefore, nonthermal acceleration is essential to understand the origin of cosmic rays. A possible candidate for the origin of cosmic rays is wakefield acceleration at relativistic astrophysical perpendicular shocks. The wakefield is considered to be excited by large-amplitude precursor light waves in the upstream of the shocks. Substituting an intensive laser pulse for the large amplitude light waves, we performed a model experiment of the shock environments in a laboratory plasma. An intensive laser pulse was propagated in a plasma tube created by imploding a hollow polystyrene cylinder, as the large amplitude light waves propagated in the upstream plasma at an astrophysical shock. Nonthermal electrons were generated, and the energy distribution functions of the electrons have a power-law component with an index of ~2. We described the detailed procedures to obtain the nonthermal components from data obtained by an electron spectrometer.
Trapped electron acceleration by a laser-driven relativistic plasma wave
Everett, M.; Lal, A.; Gordon, D.; Clayton, C. E.; Marsh, K. A.; Joshi, C.
1994-04-01
THE aim of new approaches for high-energy particle acceleration1 is to push the acceleration rate beyond the limit (~100 MeV m-1) imposed by radio-frequency breakdown in conventional accelerators. Relativistic plasma waves, having phase velocities very close to the speed of light, have been proposed2-6 as a means of accelerating charged particles, and this has recently been demonstrated7,8. Here we show that the charged particles can be trapped by relativistic plasma waves-a necessary condition for obtaining the maximum amount of energy theoretically possible for such schemes. In our experiments, plasma waves are excited in a hydrogen plasma by beats induced by two collinear laser beams, the difference in whose frequencies matches the plasma frequency. Electrons with an energy of 2 MeV are injected into the excited plasma, and the energy spectrum of the exiting electrons is analysed. We detect electrons with velocities exceeding that of the plasma wave, demonstrating that some electrons are 'trapped' by the wave potential and therefore move synchronously with the plasma wave. We observe a maximum energy gain of 28 MeV, corresponding to an acceleration rate of about 2.8 GeV m-1.
Predicting Pt-195 NMR chemical shift using new relativistic all-electron basis set.
Paschoal, D; Guerra, C Fonseca; de Oliveira, M A L; Ramalho, T C; Dos Santos, H F
2016-10-01
Predicting NMR properties is a valuable tool to assist the experimentalists in the characterization of molecular structure. For heavy metals, such as Pt-195, only a few computational protocols are available. In the present contribution, all-electron Gaussian basis sets, suitable to calculate the Pt-195 NMR chemical shift, are presented for Pt and all elements commonly found as Pt-ligands. The new basis sets identified as NMR-DKH were partially contracted as a triple-zeta doubly polarized scheme with all coefficients obtained from a Douglas-Kroll-Hess (DKH) second-order scalar relativistic calculation. The Pt-195 chemical shift was predicted through empirical models fitted to reproduce experimental data for a set of 183 Pt(II) complexes which NMR sign ranges from -1000 to -6000 ppm. Furthermore, the models were validated using a new set of 75 Pt(II) complexes, not included in the descriptive set. The models were constructed using non-relativistic Hamiltonian at density functional theory (DFT-PBEPBE) level with NMR-DKH basis set for all atoms. For the best model, the mean absolute deviation (MAD) and the mean relative deviation (MRD) were 150 ppm and 6%, respectively, for the validation set (75 Pt-complexes) and 168 ppm (MAD) and 5% (MRD) for all 258 Pt(II) complexes. These results were comparable with relativistic DFT calculation, 200 ppm (MAD) and 6% (MRD). © 2016 Wiley Periodicals, Inc.
Relativistic warm plasma theory of nonlinear laser-driven electron plasma waves.
Schroeder, C B; Esarey, E
2010-05-01
A relativistic, warm fluid model of a nonequilibrium, collisionless plasma is developed and applied to examine nonlinear Langmuir waves excited by relativistically intense, short-pulse lasers. Closure of the covariant fluid theory is obtained via an asymptotic expansion assuming a nonrelativistic plasma temperature. The momentum spread is calculated in the presence of an intense laser field and shown to be intrinsically anisotropic. Coupling between the transverse and longitudinal momentum variances is enabled by the laser field. A generalized dispersion relation is derived for Langmuir waves in a thermal plasma in the presence of an intense laser field. Including thermal fluctuations in three-velocity-space dimensions, the properties of the nonlinear electron plasma wave, such as the plasma temperature evolution and nonlinear wavelength, are examined and the maximum amplitude of the nonlinear oscillation is derived. The presence of a relativistically intense laser pulse is shown to strongly influence the maximum plasma wave amplitude for nonrelativistic phase velocities owing to the coupling between the longitudinal and transverse momentum variances.
Hramov, A E; Koronovskii, A A; Filatova, A E; 10.1063/1.4765062
2013-01-01
The report is devoted to the results of the numerical study of the virtual cathode formation conditions in the relativistic electron beam under the influence of the self-magnetic and external axial magnetic fields. The azimuthal instability of the relativistic electron beam leading to the formation of the vortex electron structure in the system was found out. This instability is determined by the influence of the self-magnetic fields of the relativistic electron beam and it leads to the decrease of the critical value of the electron beam current (current when the non-stationary virtual cathode is formed in the drift space). The typical dependencies of the critical current on the external uniform magnetic field value were discovered. The effect of the beam thickness on the virtual cathode formation conditions was also analyzed.
Taking Einstein seriously: Relativistic coupling of internal and center of mass dynamics
Krause, Dennis E
2016-01-01
Einstein's famous equation $E_{\\rm rest}=mc^2$ for the rest energy of a system with mass $m$ requires that the internal energy of the system be included in $m$. Pursuing this idea using Lagrangian and Hamiltonian dynamics yields a relativistic coupling between the center of mass motion and the internal dynamics of the system. Here we explore the consequences of this coupling, first classically, where we find that the dynamics of the system is time dilated when moving relative to another inertial frame. We then apply the dynamics to a quantum 2-level atom bound in a 1-dimensional infinite potential well, and show that the coupling produces collapses and revivals in quantum interference.
Larchenkova, T I; Lyskova, N S
2011-01-01
The images of relativistic jets from extragalactic sources produced by gravitational lensing by galaxies with different mass surface density distributions are modeled. In particular, the following models of the gravitational lens mass distribution are considered: a singular isothermal ellipsoid, an isothermal ellipsoid with a core, two- and three-component models with a galactic disk, halo, and bulge. The modeled images are compared both between themselves and with available observations. Different sets of parameters are shown to exist for the gravitationally lensed system B0218+357 in multicomponent models. These sets allow the observed geometry of the system and the intensity ratio of the compact core images to be obtained, but they lead to a significant variety in the Hubble constant determined from the modeling results.
Estimation of mass outflow rates from viscous relativistic accretion discs around black holes
Chattopadhyay, Indranil
2016-01-01
We investigated flow in Schwarzschild metric, around a non-rotating black hole and obtained self-consistent accretion - ejection solution in full general relativity. We covered the whole of parameter space in the advective regime to obtain shocked, as well as, shock-free accretion solution. We computed the jet streamline using von - Zeipel surfaces and projected the jet equations of motion on to the streamline and solved them simultaneously with the accretion disc equations of motion. We found that steady shock cannot exist {for $\\alpha \\gsim0.06$} in the general relativistic prescription, but is lower if mass - loss is considered too. We showed that for fixed outer boundary, the shock moves closer to the horizon with increasing viscosity parameter. The mass outflow rate increases as the shock moves closer to the black hole, but eventually decreases, maximizing at some intermediate value of shock {location}. The jet terminal speed increases with stronger shocks, quantitatively speaking, the terminal speed of ...
Chifu E. N.
2009-07-01
Full Text Available General Relativistic metric tensors for gravitational fields exterior to homogeneous spherical mass distributions rotating with constant angular velocity about a fixed di- ameter are constructed. The coeffcients of affine connection for the gravitational field are used to derive equations of motion for test particles. The laws of conservation of energy and angular momentum are deduced using the generalized Lagrangian. The law of conservation of angular momentum is found to be equal to that in Schwarzschild’s gravitational field. The planetary equation of motion and the equation of motion for a photon in the vicinity of the rotating spherical mass distribution have rotational terms not found in Schwarzschild’s field.
X-ray and electron generation in the relativistic lambda-cubed regime
Mordovanakis, Aghapi G.
Over the last two decades, laser-plasma interactions at relativistic intensities have been carried out using large laser facilities producing at least several hundred millijoule pulses at a repetition rate of 10 Hz or lower. A less explored regime is when intensities in excess of 1018 W/cm2 are attained by focusing millijoule-level femtosecond pulses to a spot with a diameter comparable to the laser wavelength. This so-called relativistic lambda3 regime allows the study of certain laser-plasma experiments at kilohertz repetition rate. The present dissertation contributes to the understanding of the x-ray source and hot electrons produced in this regime. The micron-sized lambda3 focus engenders a comparably sized x-ray source that could be attractive for high resolution x-ray imaging applications. With this in mind, the source size is measured for various target materials using the knife-edge technique. Furthermore, the source spatial coherence properties are investigated by analyzing the diffraction pattern off a straight edge. Also investigated are the spatial and energy distributions of hot electrons escaping the plasma. In the case of an Al plasma, the electrons have a Maxwellian-like energy distribution with a temperature that scales with (I lambda 2)0.6 in the 1017--2 x 10 18 W/cm2 intensity range. On the other hand, in the case of an SiO2 plasma with lambda/2 scale-length, the electrons are emitted in a collimated relativistic jet having a non-Maxwellian distribution with = 675 keV. This is the first demonstration of laser-generated relativistic electron beams at kilohertz repetition rate. Additionally, this dissertation reports on two pioneering demonstrations in a related but fundamentally different regime, that of high-average power fiber lasers. In the first experiment, Ni Kalpha x-rays are produced using a fiber CPA system at the intensity of 2 x 1018 W/cm 2, the highest reported to date from a fiber system. The conversion efficiency into the Kalpha
Relativistic electron dropouts by pitch angle scattering in the geomagnetic tail
J. J. Lee
2006-11-01
Full Text Available Relativistic electron dropout (RED events are characterized by fast electron flux decrease at the geostationary orbit. It is known that the main loss process is non adiabatic and more effective for the high energy particles. RED events generally start to occur at midnight sector and propagate to noon sector and are correlated with magnetic field stretching. In this paper, we discuss this kind of event can be caused from pitch angle diffusion induced when the gyro radius of the electrons is comparable to the radius of curvature of the magnetic field and the magnetic moment is not conserved any more. While this process has been studied theoretically, the question is whether electron precipitation could be explained with this process for the real field configuration. This paper will show that this process can successfully explain the precipitation that occurred on 14 June 2004 observed by the low-altitude (680 km polar orbiting Korean satellite, STSAT-1. In this precipitation event, the energy dispersion showed higher energy electron precipitation occurred at lower L values. This feature is a good indicator that precipitation was caused by the magnetic moment scattering in the geomagnetic tail. This interpretation is supported by the geosynchronous satellite GOES observations that showed significant magnetic field distortion occurred on the night side accompanying the electron flux depletion. Tsyganenko-01 model also shows the magnetic moment scattering could occur under the geomagnetic conditions existing at that time. We suggest the pitch angle scattering by field curvature violating the first adiabatic invariant as a possible candidate for loss mechanism of relativistic electrons in radiation belt.
Energy loss and longitudinal wakefield of relativistic short proton bunches in electron clouds
O. Boine-Frankenheim
2012-05-01
Full Text Available The aim of our study is the numerical computation of the wakefield and energy loss per unit length for relativistic, short (<10 ns proton bunches interacting with an electron cloud inside the beam pipe. We present analytical expressions for the energy loss in the impulse kick approximation. For the simulation of the wakefields a 2D self-consistent, electrostatic particle-in-cell (PIC code is employed. Results for the energy loss and for the wakefields are presented for the parameter scope of the CERN LHC and SPS. For selected parameters the results are compared to a three-dimensional (3D electromagnetic PIC code.
FAST TRACK COMMUNICATION: Relativistic echo dynamics and the stability of a beam of Landau electrons
Sadurní, E.; Seligman, T. H.
2008-03-01
We extend the concepts of echo dynamics and fidelity decay to relativistic quantum mechanics, specifically in the context of Klein-Gordon and Dirac equations under external electromagnetic fields. In both cases, we define similar expressions for the fidelity amplitude under perturbations of these fields and a covariant version of the echo operator. Transformation properties under the Lorentz group are established. An alternate expression for fidelity is given in the Dirac case in terms of a 4-current. As an application, we study a beam of Landau electrons perturbed by field inhomogeneities.
Relativistic echo dynamics and the stability of a beam of Landau electrons
SadurnI, E; Seligman, T H [Instituto de Ciencias Fisicas, Universidad Nacional Autonoma de Mexico, Cuernavaca, Morelos (Mexico)], E-mail: sadurni@fis.unam.mx, E-mail: seligman@fis.unam.mx
2008-03-14
We extend the concepts of echo dynamics and fidelity decay to relativistic quantum mechanics, specifically in the context of Klein-Gordon and Dirac equations under external electromagnetic fields. In both cases, we define similar expressions for the fidelity amplitude under perturbations of these fields and a covariant version of the echo operator. Transformation properties under the Lorentz group are established. An alternate expression for fidelity is given in the Dirac case in terms of a 4-current. As an application, we study a beam of Landau electrons perturbed by field inhomogeneities. (fast track communication)
Heavy meson masses and decay constants from relativistic heavy quarks in full lattice QCD
McNeile, C; Follana, E; Hornbostel, K; Lepage, G P
2012-01-01
We determine masses and decay constants of heavy-heavy and heavy-charm pseudoscalar mesons as a function of heavy quark mass using a fully relativistic formalism known as Highly Improved Staggered Quarks for the heavy quark. We are able to cover the region from the charm quark mass to the bottom quark mass using MILC ensembles with lattice spacing values from 0.15 fm down to 0.044 fm. We obtain f_{B_c} = 0.427(6) GeV; m_{B_c} = 6.285(10) GeV and f_{\\eta_b} = 0.667(6) GeV. Our value for f_{\\eta_b} is within a few percent of f_{\\Upsilon} confirming that spin effects are surprisingly small for heavyonium decay constants. Our value for f_{B_c} is significantly lower than potential model values being used to estimate production rates at the LHC. We discuss the changing physical heavy-quark mass dependence of decay constants from heavy-heavy through heavy-charm to heavy-strange mesons. A comparison between the three different systems confirms that the B_c system behaves in some ways more like a heavy-light system t...
Gray, R. J.; MacLellan, D. A.; Gonzalez-Izquierdo, B.; Powell, H. W.; Carroll, D. C.; Murphy, C. D.; Stockhausen, L. C.; Rusby, D. R.; Scott, G. G.; Wilson, R.; Booth, N.; Symes, D. R.; Hawkes, S. J.; Torres, R.; Borghesi, M.; Neely, D.; McKenna, P.
2014-09-01
Asymmetry in the collective dynamics of ponderomotively-driven electrons in the interaction of an ultraintense laser pulse with a relativistically transparent target is demonstrated experimentally. The 2D profile of the beam of accelerated electrons is shown to change from an ellipse aligned along the laser polarization direction in the case of limited transparency, to a double-lobe structure aligned perpendicular to it when a significant fraction of the laser pulse co-propagates with the electrons. The temporally-resolved dynamics of the interaction are investigated via particle-in-cell simulations. The results provide new insight into the collective response of charged particles to intense laser fields over an extended interaction volume, which is important for a wide range of applications, and in particular for the development of promising new ultraintense laser-driven ion acceleration mechanisms involving ultrathin target foils.
2-D studies of Relativistic electron beam plasma instabilities in an inhomogeneous plasma
Shukla, Chandrashekhar; Patel, Kartik
2015-01-01
Relativistic electron beam propagation in plasma is fraught with several micro instabilities like two stream, filamentation etc., in plasma. This results in severe limitation of the electron transport through a plasma medium. Recently, however, there has been an experimental demonstration of improved transport of Mega Ampere of electron currents (generated by the interaction of intense laser with solid target) in a carbon nanotube structured solid target [Phys. Rev Letts. 108, 235005 (2012)]. This then suggests that the inhomogeneous plasma (created by the ionization of carbon nano tube structured target) helps in containing the growth of the beam plasma instabilities. This manuscript addresses this issue with the help of a detailed analytical study and simulations with the help of 2-D Particle - In - Cell code. The study conclusively demonstrates that the growth rate of the dominant instability in the 2-D geometry decreases when the plasma density is chosen to be inhomogeneous, provided the scale length 1/ks...
Non-linear Ion-wake Excitation by Ultra-relativistic Electron Wakefields
Sahai, Aakash A
2015-01-01
The excitation of a non-linear ion-wake by a train of ultra-relativistic plasmons is modeled and its use for a novel regime of positron acceleration is explored. Its channel-like structure is independent of the energy-source driving the bubble-shaped slowly-propagating high phase-velocity electron density waves. The back of the bubble electron compression sucks-in the ions and the space-charge within the bubble expels them, forming a near-void channel with on-axis and bubble-edge density-spikes. The channel-edge density-spike is driven radially outwards as a non-linear ion acoustic-wave by the wake electron thermal pressure. OSIRIS PIC simulations are used to study the ion-wake structure, its evolution and its use for positron acceleration.
Roussel, E; Szwaj, M Le Parquier C; Manceron, L; Brubach, J -B; Tordeux, M -A; Ricaud, J -P; Cassinari, L; Labat, M; Couprie, M -E; Roy, P; Bielawski, S
2014-01-01
Relativistic electron bunches are powerful light sources, which are largely exploited in synchrotron radiation facilities, and are crucial for most sciences. However, electrons bunches suffer from instabilities, leading to spontaneous spatial structure formation. This effect --recalling fluid turbulence issues-- represents a fundamental limitation for light sources, and simultaneously an opportunity because the structures emit high powers of terahertz radiation ($>$10000 times normal synchrotron radiation). Up to now, though crucial for understanding and mastering synchrotron sources, observations of the structures remained a largely open problem, because of their extreme evolution speed. Here we demonstrate the possibility of direct observation by adapting a technique from photonics, {\\it time-strech}, consisting in "slowing-down" the phenomena prior to recording. As a main result, we present the first recording of electron bunch microstructures versus time, with submillimeter resolution, in a storage ring. ...
Femtosecond probing of light-speed plasma wakefields by using a relativistic electron bunch
Zhang, C J; Wan, Y; Guo, B; Wu, Y P; Pai, C -H; Li, F; Chu, H -H; Gu, Y Q; Xu, X L; Mori, W B; Joshi, C; Wang, J; Lu, W
2016-01-01
Relativistic wakes produced by intense laser or particle beams propagating through plasmas are being considered as accelerators for next generation of colliders and coherent light sources. Such wakes have been shown to accelerate electrons and positrons to several gigaelectronvolts (GeV), with a few percent energy spread and a high wake-to-beam energy transfer efficiency. However, complete mapping of electric field structure of the wakes has proven elusive. Here we show that a high-energy electron bunch can be used to probe the fields of such light-speed wakes with femtosecond resolution. The highly transient, microscopic wakefield is reconstructed from the density modulated ultra-short probe bunch after it has traversed the wake. This technique enables visualization of linear wakefields in low-density plasmas that can accelerate electrons and positrons beams. It also allows characterization of wakes in plasma density ramps critical for maintaining the beam emittance, improving the energy transfer efficiency ...
High power THz source based on coherent radiation of picosecond relativistic electron bunch train
无
2011-01-01
Tunable and compact high power terahertz (THz) radiation based on coherent radiation (CR) of the picosecond relativistic electron bunch train is under development at the Tsinghua accelerator lab. Coherent synchronization radiation (CSR) and coherent transition radiation (CTR) are researched based on an S-band compact electron linac, a bending magnet or a thin foil. The bunch train’s form factors, which are the key factor of THz radiation, are analyzed by the PARMELA simulation. The effects of electron bunch trains under different conditions, such as the bunch number, bunch charges, micro-pulses inter-distance, and accelerating gradient of the gun are investigated separately in this paper. The optimal radiated THz power and spectra should take these factors as a whole into account.
A. Chandrasekhar Reddy; Jatin Rathod; Girija Rajaram; Radharani Alyana; D. S. Misra; C. G. Patil; M. Y. S. Prasad; A. G. Ananth
2008-03-01
In view of the renewed interest in the study of energetic particles in the outer radiation belt of the earth, we feel it will be helpful in looking for the energy dependence of the electron energy spectrum at geostationary orbit. This may give us some insight into how we can safeguard geostationary satellites from functional anomalies of the deep dielectric charging type, which are caused by charge accumulation and subsequent discharge of relativistic electrons. In this study we examine whether there is any energy dependence in relativistic electron enhancements at geosynchronous altitudes during solar energetic proton events of 2005.
Scott, R H H; Perez, F; Streeter, M J V; Davies, J R; Schlenvoigt, H -P; Santos, J J; Hulin, S; Lancaster, K L; Baton, S D; Rose, S J; Norreys, P A
2013-01-01
A photon detector suitable for the measurement of bremsstrahlung spectra generated in relativistically-intense laser-solid interactions is described. The Monte Carlo techniques used to back-out the fast electron spectrum and laser energy absorbed into fast electrons are detailed. A relativistically-intense laser-solid experiment using frequency doubled laser light is used to demonstrate the effective operation of the detector. The experimental data was interpreted using the 3-spatial-dimension Monte Carlo code MCNPX (Pelowitz 2008), and the fast electron temperature found to be 125 keV.
Scott, R H H; Clark, E L; Pérez, F; Streeter, M J V; Davies, J R; Schlenvoigt, H-P; Santos, J J; Hulin, S; Lancaster, K L; Baton, S D; Rose, S J; Norreys, P A
2013-08-01
A photon detector suitable for the measurement of bremsstrahlung spectra generated in relativistically intense laser-solid interactions is described. The Monte Carlo techniques used to extract the fast electron spectrum and laser energy absorbed into forward-going fast electrons are detailed. A relativistically intense laser-solid experiment using frequency doubled laser light is used to demonstrate the effective operation of the detector. The experimental data were interpreted using the 3-spatial-dimension Monte Carlo code MCNPX [D. Pelowitz, MCNPX User's Manual Version 2.6.0, Los Alamos National Laboratory, 2008], and the fast electron temperature found to be 125 keV.
Hafez, M. G.; Roy, N. C.; Talukder, M. R.; Hossain Ali, M.
2016-09-01
This work investigates the oblique nonlinear propagation of ion acoustic (IA) shock waves for both weakly and highly relativistic plasmas composed of nonthermal electrons and positrons with relativistic thermal ions. The KdVB-like equation, involving dispersive, weakly transverse dispersive, nonlinearity and dissipative coefficients, is derived employing the well known reductive perturbation method. The integration of this equation is carried out by the {tanh} method taking the stable shock formation condition into account. The effects of nonthermal electrons and positrons, nonthermal electrons with isothermal positrons, isothermal electrons with nonthermal positrons, and isothermal electrons and positrons on oblique propagation of IA shock waves in weakly relativistic regime are described. Furthermore, the effects of plasma parameters on oblique propagation of IA shock waves in highly relativistic regime are discussed and compared with weakly relativistic case. It is seen that the plasma parameters within certain limits significantly modify the structures of the IA shock waves in both cases. The results may be useful for better understanding of the interactions of charged particles with extra-galactic jets as well as astrophysical compact objects.
A study of the runaway relativistic electron avalanche and the feedback theory using GEANT4
Broberg Skeltved, Alexander; Østgaard, Nikolai; Carlson, Brant; Gjesteland, Thomas
2014-05-01
This study investigate the Runaway Relativistic Electron Avalanche (RREA) and the feedback process as well as the production of Bremsstrahlung photons from Runaway Electrons (REs). These processes are important to understand the production of the intense bursts of gamma-rays known as Terrestrial Gamma-Ray Flashes (TGFs). Results are obtained from Monte Carlo (MC) simulations using the GEometry ANd Tracking 4 (GEANT4) programming toolkit. The simulations takes into account the effects of electron ionisation, electron by electron scattering (Møller scattering) as well as positron and photon interactions, in the 250 eV-100 GeV energy range. Several physics libraries or 'physics lists' are provided with GEANT4 to implement these physics processes in the simulations. We give a detailed analysis of the electron and the feedback multiplication, in particular the avalanche lengths, Λ, the energy distribution and the feedback factor, γ. We also find that our results vary significantly depending on which physics list we implement. In order to verify our results and the GEANT4 programming toolkit, we compare them to previous results from existing models. In addition we present the ratio of the production of bremsstrahlung photons to runaway electrons. From this ratio we obtain the parameter, α, which describe the electron to photon relation.
Relativistic electron transport in wire and foil targets driven by intense short pulse lasers
Mason, R. J.; Stephens, R. B.; Wei, M.; Freeman, R. R.; Hill, J.; van Woerkom, L. D.
2006-10-01
We model intense laser driven electron transport in wires and foils with the new implicit hybrid code e-PLAS. We focus on background plasma heating for Fast Ignitor applications. The model tracks collisional relativistic PIC electrons undergoing scatter and drag in a background plasma of colliding cold electron and ion Eulerian fluids. Application to 10 μm diameter, 250 μm long, fully ionized carbon wires with an attached cone [Kodama et al. Nature 432 1005 (2004)], exposed to 1 ps, 10^19 W/cm^2 pulses in a 30 μm centered spot, directly calculates resistive Joule heating of the background electrons in the wire to 1.7 KeV. 150 MG magnetic fields arise at the wire surfaces corresponding to hot electron flow outside the wire and a return electron flow just within it. Shorter wires (25 μm) exhibit hot electron recycling. Preliminary simulations indicate that reduction of the cone to a 30 μm diameter nail head produces little change in these results. We also report on tapered wires, wires attached to foils, and the modifying effects of pre-plasma on electron transport into the foils.
Arefiev, A. V.; Khudik, V. N.; Robinson, A. P. L.; Shvets, G.; Willingale, L.; Schollmeier, M.
2016-05-01
We examine a regime in which a linearly polarized laser pulse with relativistic intensity irradiates a sub-critical plasma for much longer than the characteristic electron response time. A steady-state channel is formed in the plasma in this case with quasi-static transverse and longitudinal electric fields. These relatively weak fields significantly alter the electron dynamics. The longitudinal electric field reduces the longitudinal dephasing between the electron and the wave, leading to an enhancement of the electron energy gain from the pulse. The energy gain in this regime is ultimately limited by the superluminosity of the wave fronts induced by the plasma in the channel. The transverse electric field alters the oscillations of the transverse electron velocity, allowing it to remain anti-parallel to laser electric field and leading to a significant energy gain. The energy enhancement is accompanied by the development of significant oscillations perpendicular to the plane of the driven motion, making trajectories of energetic electrons three-dimensional. Proper electron injection into the laser beam can further boost the electron energy gain.
Mori, M; Daito, I; Kotaki, H; Hayashi, Y; Yamazaki, A; Ogura, K; Sagisaka, A; Koga, J; Nakajima, K; Daido, H; Bulanov, S V; Kimura, T
2006-01-01
The regimes of quasi-mono-energetic electron beam generation were experimentally studied in the sub-relativistic intensity laser plasma interaction. The observed electron acceleration regime is unfolded with two-dimensional-particle-in-cell simulations of laser-wakefield generation in the self-modulation regime.
Lysenko, Alexander V.; Volk, Iurii I.; Serozhko, A.
2017-01-01
We elaborate a quadratic nonlinear theory of plural interactions of growing space charge wave (SCW) harmonics during the development of the two-stream instability in helical relativistic electron beams. It is found that in helical two-stream electron beams the growth rate of the two-stream instab...
Time Asymmetric Boundary Conditions and the Definition of Mass and Width for Relativistic Resonances
Bohm, A R; Tay, B A; Kielanowski, Piotr
2001-01-01
The definition of mass and width of relativistic resonances and in particular of the $Z$-boson is discussed. For this we use the theory based on time asymmetric boundary conditions given by Hardy class spaces ${\\mathbf \\Phi}_-$ and ${\\mathbf \\Phi}_+$ for prepared in-states and detected out-states respectively, rather than time symmetric Hilbert space theory. This Hardy class boundary condition is a mathematically rigorous form of the singular Lippmann-Schwinger equation. In addition to the rigorous definition of the Lippmann-Schwinger kets $|[j,{\\mathsf s}]^{\\pm}>$ as functionals on the spaces ${\\mathbf \\Phi}_{\\mp}$, one obtains Gamow kets $|[j,{\\mathsf s}_R]^- >$ with complex centre-of-mass energy value ${\\mathsf s}_R=(M_R-i\\Gamma_R/2)^2$. The Gamow kets have an exponential time evolution given by $\\exp{(-iM_Rt-\\Gamma_Rt/2)}$ which suggests that $(M_R,\\Gamma_R)$ is the right definition of the mass and width of a resonance. This is different from the two definitions of the $Z$-boson mass and width used in the...
Hamilton, Andrew J S
2008-01-01
If you fall into a real astronomical black hole (choosing a supermassive black hole, to make sure that the tidal forces don't get you first), then you will probably meet your fate not at a central singularity, but rather in the exponentially growing, relativistic counter-streaming instability at the inner horizon first pointed out by Poisson & Israel (1990), who called it mass inflation. The purpose of this paper is to present a clear exposition of the physical cause and consequence of inflation in spherical, charged black holes. Inflation acts like a particle accelerator in that it accelerates cold ingoing and outgoing streams through each other to prodigiously high energies. Inflation feeds on itself: the acceleration is powered by the gravity produced by the streaming energy.
Disperson relation of finite amplitude Alfven wave in a relativistic electron- positron plasma
Hada, T; Muñoz, V; Hada, Tohru; Matsukiyo, Shuichi; Munoz, Victor
2004-01-01
The linear dispersion relation of a finite amplitude, parallel, circularly polarized Alfv\\'en wave in a relativistic electron-positron plasma is derived. In the nonrelativistic regime, the dispersion relation has two branches, one electromagnetic wave, with a low frequency cutoff at $\\sqrt{1+2\\omega_p^2/\\Omega_p^2}$ (where $\\omega_p=(4\\pi n e^2/m)^{1/2}$ is the electron/positron plasma frequency), and an Alfv\\'en wave, with high frequency cutoff at the positron gyrofrequency $\\Omega_p$. There is only one forward propagating mode for a given frequency. However, due to relativistic effects, there is no low frequency cutoff for the electromagnetic branch, and there appears a critical wave number above which the Alfv\\'en wave ceases to exist. This critical wave number is given by $ck_c/\\Omega_p=a/\\eta$, where $a=\\omega_p^2/\\Omega_p^2$ and $\\eta$ is the ratio between the Alfv\\'en wave magnetic field amplitude and the background magnetic field. In this case, for each frequency in the Alfv\\'en branch, two additional...
Yeung, M.; Rykovanov, S.; Bierbach, J.; Li, L.; Eckner, E.; Kuschel, S.; Woldegeorgis, A.; Rödel, C.; Sävert, A.; Paulus, G. G.; Coughlan, M.; Dromey, B.; Zepf, M.
2017-01-01
Energy coupling during relativistically intense laser-matter interactions is encoded in the attosecond motion of strongly driven electrons at the pre-formed plasma-vacuum boundary. Studying and controlling this motion can reveal details about the microscopic processes that govern a vast array of light-matter interaction phenomena, including those at the forefront of extreme laser-plasma science such as laser-driven ion acceleration, bright attosecond pulse generation and efficient energy coupling for the generation and study of warm dense matter. Here we experimentally demonstrate that by precisely adjusting the relative phase of an additional laser beam operating at the second harmonic of the driving laser it is possible to control the trajectories of relativistic electron bunches formed during the interaction with a solid target at the attosecond scale. We observe significant enhancements in the resulting high-harmonic yield, suggesting potential applications for sources of ultra-bright, extreme ultraviolet attosecond radiation to be used in atomic and molecular pump-probe experiments.
Relativistic equation-of-motion coupled-cluster method for the electron attachment problem
Pathak, Himadri; Nayak, Malaya K; Vaval, Nayana; Pal, Sourav
2016-01-01
The article considers the successful implementation of relativistic equation-of-motion coupled clus- ter method for the electron attachment problem (EA-EOMCC) at the level of single- and double- excitation approximation. The Dirac-Coulomb Hamiltonian is used to generate the single particle orbitals and two-body matrix elements. The implemented relativistic EA-EOMCC method is em- ployed to calculate ionization potential values of alkali metal atoms (Li, Na, K, Rb, Cs, Fr) and the vertical electron affinity values of LiX (X=H, F, Cl, Br), NaY (Y=H, F, Cl) starting from their closed-shell configuration. We have taken C 2 as an example to understand what should be the na- ture of the basis and cut off in the orbital energies that can be used for the correlation calculations without loosing a considerable amount of accuracy in the computed values. Both four-component and X2C calculations are done for all the opted systems to understand the effect of relativity in our calculations as well as to justify the fact tha...
Ion-acoustic rogue waves and breathers in relativistically degenerate electron-positron plasmas
Abdikian, A.; Ismaeel, S.
2017-08-01
In this paper, we employ a weakly relativistic fluid model to study the nonlinear amplitude modulation of electrostatic waves in an unmagnetized electron-positron-ion plasma. It is assumed that the degeneracy pressure law for electrons and positrons follows the Chandrasekhar limit of state whereas ions are warm and classical. The hydrodynamic approach along with the perturbation method have been applied to obtain the corresponding nonlinear Schrödinger equation (NLSE) in which nonlinearity is in balance with the dispersive terms. Using the NLSE, we could evaluate the modulational instability to show that various types of localized ion acoustic excitations exist in the form of either bright-type envelope solitons or dark-type envelope solitons. The regions of the stable and unstable envelope wave have been confined punctually for various regimes. Furthermore, it is proposed that the exact solutions of the NLSE for breather waves are the rogue waves (RWs), Akhmediev breather (AB), and Kuznetsov-Ma breather (KM) soliton. In order to show that the characteristics of breather structures is influenced by the plasma parameters (namely, relativistic parameter, positron concentration, and ionic temperature), the relevant numerical analysis of the NLSE is examined. In particular, it is observed that by increasing the values of the mentioned plasma parameters, the amplitude of the RWs will be decreased. Our results help researchers to explain the formation and dynamics of nonlinear electrostatic excitations in super dense astrophysical regimes.
Effect of the plasma-generated magnetic field on relativistic electron transport.
Nicolaï, Ph; Feugeas, J-L; Regan, C; Olazabal-Loumé, M; Breil, J; Dubroca, B; Morreeuw, J-P; Tikhonchuk, V
2011-07-01
In the fast-ignition scheme, relativistic electrons transport energy from the laser deposition zone to the dense part of the target where the fusion reactions can be ignited. The magnetic fields and electron collisions play an important role in the collimation or defocusing of this electron beam. Detailed description of these effects requires large-scale kinetic calculations and is limited to short time intervals. In this paper, a reduced kinetic model of fast electron transport coupled to the radiation hydrodynamic code is presented. It opens the possibility to carry on hybrid simulations in a time scale of tens of picoseconds or more. It is shown with this code that plasma-generated magnetic fields induced by noncollinear temperature and density gradients may strongly modify electron transport in a time scale of a few picoseconds. These fields tend to defocus the electron beam, reducing the coupling efficiency to the target. This effect, that was not seen before in shorter time simulations, has to be accounted for in any ignition design using electrons as a driver.
Baker, D. N.; Blake, J. B.; Callis, L. B.; Cummings, J. R.; Hovestadt, D.; Kanekal, S.; Klecker, B.; Mewaldt, R. A.; Zwickl, R. D.
1994-01-01
High-energy electrons have been measured systematically in a low-altitude (520 x 675 km), nearly polar (inclination = 82 deg) orbit by sensitive instruments onboard the Solar, Anomalous, and Magnetospheric Particle Explorer (SAMPEX). Count rate channels with electron energy thresholds ranging from 0.4 MeV to 3.5 MeV in three different instruments have been used to examine relativistic electron variations as a function of L-shell parameter and time. A long run of essentially continuous data (July 1992 - July 1993) shows substantial acceleration of energetic electrons throughout much of the magnetosphere on rapid time scales. This acceleration appears to be due to solar wind velocity enhancements and is surprisingly large in that the radiation belt 'slot' region often is filled temporarily and electron fluxes are strongly enhanced even at very low L-values (L aprroximately 2). A superposed epoch analysis shows that electron fluxes rise rapidly for 2.5 is approximately less than L is approximately less than 5. These increases occur on a time scale of order 1-2 days and are most abrupt for L-values near 3. The temporal decay rate of the fluxes is dependent on energy and L-value and may be described by J = Ke-t/to with t(sub o) approximately equals 5-10 days. Thus, these results suggest that the Earth's magnetosphere is a cosmic electron accelerator of substantial strength and efficiency.
Gu, X., E-mail: xgu@bnl.gov; Altinbas, F.Z.; Beebe, E.; Fischer, W.; Frak, B.M.; Gassner, D.M.; Hamdi, K.; Hock, J.; Hoff, L.; Kankiya, P.; Lambiase, R.; Luo, Y.; Mapes, M.; Mi, J.; Miller, T.; Montag, C.; Nemesure, S.; Okamura, M.; Olsen, R.H.; Pikin, A.I.; and others
2014-04-11
To compensate for the beam–beam effects from the proton–proton interactions at the two interaction points IP6 and IP8 in the Relativistic Heavy Ion Collider (RHIC), we are constructing two electron lenses (e-lenses) that we plan to install in the interaction region IR10. Before installing them, the electron gun, collector, instrumentation were tested and the electron beam properties were qualified on an electron lens test bench. We will present the test results and discuss our measurement of the electron beam current and of the electron gun perveance. We achieved a maximum current of 1 A with 5 kV energy for both the pulsed- and the DC-beam (which is a long turn-by-turn pulse beam). We measured beam transverse profiles with an yttrium aluminum garnet (YAG) screen and pinhole detector, and compared those to simulated beam profiles. Measurements of the pulsed electron beam stability were obtained by measuring the modulator voltage.
Gu, X.; Altinbas, F. Z.; Beebe, E.; Fischer, W.; Frak, B. M.; Gassner, D. M.; Hamdi, K.; Hock, J.; Hoff, L.; Kankiya, P.; Lambiase, R.; Luo, Y.; Mapes, M.; Mi, J.; Miller, T.; Montag, C.; Nemesure, S.; Okamura, M.; Olsen, R. H.; Pikin, A. I.; Raparia, D.; Rosas, P. J.; Sandberg, J.; Tan, Y.; Theisen, C.; Tuozzolo, J.; Zhang, W.
2014-04-01
To compensate for the beam-beam effects from the proton-proton interactions at the two interaction points IP6 and IP8 in the Relativistic Heavy Ion Collider (RHIC), we are constructing two electron lenses (e-lenses) that we plan to install in the interaction region IR10. Before installing them, the electron gun, collector, instrumentation were tested and the electron beam properties were qualified on an electron lens test bench. We will present the test results and discuss our measurement of the electron beam current and of the electron gun perveance. We achieved a maximum current of 1 A with 5 kV energy for both the pulsed- and the DC-beam (which is a long turn-by-turn pulse beam). We measured beam transverse profiles with an yttrium aluminum garnet (YAG) screen and pinhole detector, and compared those to simulated beam profiles. Measurements of the pulsed electron beam stability were obtained by measuring the modulator voltage.
On relativistic motion of a pair of particles having opposite signs of masses
Ivanov, Pavel B.
2012-12-01
In this methodological note, we consider, in a weak-fleld limit, the relativistic linear motion of two particles with masses of opposite signs and a small difference between their absolute values: m_{1,2}=+/- (\\mu+/- \\Delta \\mu) , \\mu \\gt 0, \\vert\\Delta \\mu \\vert \\ll\\mu. In 1957, H Bondi showed in the framework of both Newtonian analysis and General Relativity that, when the relative motion of particles is absent, such a pair can be accelerated indefinitely. We generalize the results of his paper to account for the small nonzero difference between the velocities of the particles. Assuming that the weak-field limit holds and the dynamical system is conservative, an elementary treatment of the problem based on the laws of energy and momentum conservation shows that the system can be accelerated indefinitely, or attain very large asymptotic values of the Lorentz factor \\gamma. The system experiences indefinite acceleration when its energy-momentum vector is null and the mass difference \\Delta \\mu \\le 0. When the modulus of the square of the norm of the energy-momentum vector, \\vert N^{\\,2}\\vert, is sufficiently small, the system can be accelerated to very large \\gamma \\propto \\vert N^{\\,2}\\vert^{-1}. It is stressed that, when only leading terms in the ratio of a characteristic gravitational radius to the distance between the particles are retained, our elementary analysis leads to equations of motion equivalent to those derived from relativistic weak-field equations of motion by Havas and Goldberg in 1962. Thus, in the weak-field approximation it is possible to bring the system to the state with extremely high values of \\gamma. The positive energy carried by the particle with positive mass may be conveyed to other physical bodies, say by intercepting this particle with a target. If we suppose that there is a process of production of such pairs and the particles with positive mass are intercepted, while the negative mass particles are expelled
Pareja, M J
2003-01-01
For relativistic stars rotating slowly and differentially with a positive angular velocity, some properties in relation to the positiveness of the rate of rotational dragging and of the angular momentum density are derived. Also, a new proof for the bounds on the rotational mass-energy is given.
Kaplin, V V; Uglov, S R; Bulaev, O F; Voronin, A A; Piestrup, M; Gary, C
2006-01-01
In this work we have observed x-ray emission from x-ray waveguide radiator excited by relativistic electrons. The experiment carried out at Tomsk betatron B-35. Such new type stratified target was mounted on goniometer head inside the betatron toroid. The target is consisted of the W-C-W layers placed on Si substrate. The photographs of the angular distributions of the radiation generated in the target by 20-33 MeV electrons have shown the waveguide effect of the three-layer structure on x-rays generated in the target. The effect proved in an angular distribution of radiation as an additional narrow peak of guided x-rays intensity inside a wide cone of usual Bremsstrahlung.
Model operator approach to the Lamb shift calculations in relativistic many-electron atoms
Shabaev, V M; Yerokhin, V A
2013-01-01
A model operator approach to calculations of the QED corrections to energy levels in relativistic many-electron atomic systems is developed. The model Lamb shift operator is represented by a sum of local and nonlocal potentials which are defined using the results of ab initio calculations of the diagonal and nondiagonal matrix elements of the one-loop QED operator with H-like wave functions. The model operator can be easily included in any calculations based on the Dirac-Coulomb-Breit Hamiltonian. Efficiency of the method is demonstrated by comparison of the model QED operator results for the Lamb shifts in many-electron atoms and ions with exact QED calculations.
Simulation of planar FEL-amplifier with tape relativistic electron beam
Ginzburg, N S; Peskov, N Yu; Arzhannikov, A V; Sinitskij, S L
2001-01-01
The simulation of the planar microwave (4 mm) amplifier on the basis of the powerful laser on free electrons (FEL- amplifier) is carried out. The tape relativistic electron beam with the energy up to 1 MeV and operating current up to 2 kA is formed by the Y-3 accelerators. The complete nonaveraging system of the self-consistent equations describing the process of interaction of the particles, moving in the plane ondulator field is obtained. Thereafter the averaging of the above-mentioned equations was carried out and the linear and nonlinear stages of the amplification process were studied. The additional simulation of the FEL-amplifier is carried out on the basis of the two-dimensional version of the KARAT PIC-code. It is shown that the applied approaches give sufficiently close results
Longitudinal and transverse cooling of relativistic electron beams in intense laser pulses
Yoffe, Samuel R; Noble, Adam; Jaroszynski, Dino A
2015-01-01
With the emergence in the next few years of a new breed of high power laser facilities, it is becoming increasingly important to understand how interacting with intense laser pulses affects the bulk properties of a relativistic electron beam. A detailed analysis of the radiative cooling of electrons indicates that, classically, equal contributions to the phase space contraction occur in the transverse and longitudinal directions. In the weakly quantum regime, in addition to an overall reduction in beam cooling, this symmetry is broken, leading to significantly less cooling in the longitudinal than the transverse directions. By introducing an efficient new technique for studying the evolution of a particle distribution, we demonstrate the quantum reduction in beam cooling, and find that it depends on the distribution of energy in the laser pulse, rather than just the total energy as in the classical case.
Roussel, E; Evain, C; Szwaj, C; Bielawski, S; Raasch, J; Thoma, P; Scheuring, A; Hofherr, M; Ilin, K; Wünsch, S; Siegel, M; Hosaka, M; Yamamoto, N; Takashima, Y; Zen, H; Konomi, T; Adachi, M; Kimura, S; Katoh, M
2014-08-29
Relativistic electron bunches circulating in accelerators are subjected to a dynamical instability leading to microstructures at millimeter to centimeter scale. Although this is a well-known fact, direct experimental observations of the structures, or the field that they emit, remained up to now an open problem. Here, we report the direct, shot-by-shot, time-resolved recording of the shapes (including envelope and carrier) of the pulses of coherent synchrotron radiation that are emitted, and that are a "signature" of the electron bunch microstructure. The experiments are performed on the UVSOR-III storage ring, using electrical field sensitive YBa2Cu3O(7-x) thin-film ultrafast detectors. The observed patterns are subjected to permanent drifts, that can be explained from a reasoning in phase space, using macroparticle simulations.
Yang, X. H.; Zhuo, H. B.; Xu, H.; Ge, Z. Y.; Shao, F. Q.; Borghesi, M.; Ma, Y. Y.
2016-10-01
Generation of relativistic electron (RE) beams during ultraintense laser pulse interaction with plasma targets is studied by collisional particle-in-cell simulations. A strong magnetic field with a transverse scale length of several local plasma skin depths, associated with RE current propagation in the target, is generated by filamentation instability in collisional plasmas, inducing a great enhancement of the divergence of REs compared to that of collisionless cases. Such an effect is increased with laser intensity and target charge state, suggesting that the RE divergence might be improved by using low-Z materials under appropriate laser intensities in future fast ignition experiments and in other applications of laser-driven electron beams.
Higher harmonic emission by a relativistic electron beam in a longitudinal magnetic wiggler
Davidson, Ronald C.; McMullin, Wayne A.
1982-10-01
The classical limit of the Einstein-coefficient method is used in the low-gain regime to calculate the stimulated emission from a tenuous relativistic electron beam propagating in the combined solenoidal and longitudinal wiggler fields (B0+δB k0z)e^z produced near the axis of a multiple-mirror (undulator) field configuration. Emission is found to occur at all harmonics of the wiggler wave number k0 with Doppler upshifted output frequency given by ω=(lk0Vb+ωcb)(1+Vbc)γ2b(1+γ2bV2⊥c2), where l>=1. The emission is compared to the low-gain cyclotron maser with δB=0 and to the low-gain free-electron laser (operating at higher harmonics) utilizing a transverse linearly polarized wiggler field.
Bering, E. A.; Kokorowski, M.; Holzworth, R. H.; Sample, J. G.; McCarthy, M. P.; Smith, D. M.; Parks, G. K.; Millan, R. M.; Woodger, L.; Reddell, B. D.; Lay, E.; Bale, S. D.; Pulupa, M.; O'Brien, T. P.; Blake, J. B.; Lin, R. P.; Moraal, H.; Stoker, P.; Hughes, A. R.; Collier, A. B.
2005-05-01
The MINIS balloon campaign was successfully conducted in January 2005 to investigate relativistic electron loss mechanisms. Quantifying and understanding losses is an integral part of understanding the variability of relativistic electrons in the radiation belts. Balloon-based experiments directly measure precipitation and thus provide a method for quantifying losses, while the nearly stationary platform allows for the separation of temporal and spatial variations. A new class of precipitation event, characterized by extremely hard spectra, short durations, and complex temporal structure, occurring in the evening to midnight sector, was discovered by the INTERBOA balloon in 1996 and studied further by the MAXIS balloon in 2000. The MINIS campaign provided the first opportunities for multi-point measurements of electron precipitation up to MeV energies, including simultaneous measurements at different longitudes and at near-conjugate locations. Two balloons, each carrying an X-ray spectrometer for measuring the bremsstrahlung produced as electrons precipitate into the atmosphere, were launched from Churchill, Manitoba at 0850 UT on 21 January 2005 and 0140 UT on 25 January 2005. Four balloons, each carrying an X-ray spectrometer, a Z-axis search coil magnetometer, and a 3-axis electric field instrument providing DC electric field and VLF measurements in 3 frequency bands, were launched from the South African Antarctic Station (SANAE IV). The Southern launches took place at 1400 UT on 17 January, 1309 UT on 19 January, 2115 UT on 20 January, and 0950 UT on 24 January 2005. In this paper, we present the preliminary results from the MINIS South electric field instrumentation. We have good DC and VLF electric field data from all payloads, and the payload rotation mechanism worked in all four as well. The campaign began with two large solar flares. In the post-flare environment, some very magnetospherically active periods are included in our data, with strong and
Preliminary X-ray Results From A Multiple Balloon Campaign to Study Relativistic Electron Loss
Sample, J. G.; Kokorowski, M.; Millan, R. M.; McCarthy, M.; Holzworth, R. H.; Bering, E. A.; Parks, G. K.; Woodger, L.; Reddell, B. D.; Lay, E.; Pulupa, M.; Bale, S.; O'Brien, T. P.; Blake, J. B.; Lin, R. P.; Moraal, H.; Stoker, P.; Hughes, A. R.; Collier Cameron, A.; Smith, D. M.
2005-05-01
The MINIS balloon campaign was successfully conducted in January 2005 to investigate relativistic electron loss mechanisms. Quantifying and understanding losses is an integral part of understanding the variability of relativistic electrons in the radiation belts. Balloon-based experiments directly measure precipitation and thus provide a method for quantifying losses, while the nearly stationary platform allows for the separation of temporal and spatial variations. A new class of precipitation event, characterized by extremely hard spectra, short durations, and complex temporal structure, occurring in the evening to midnight sector, was discovered by the INTERBOA balloon in 1996 and studied further by the MAXIS balloon in 2000. The MINIS campaign provided the first opportunities for multi-point measurements of electron precipitation up to MeV energies, including simultaneous measurements at different longitudes and at near-conjugate locations. Two balloons, each carrying an X-ray spectrometer for measuring the bremsstrahlung produced as electrons precipitate into the atmosphere, were launched from Churchill, Manitoba at 0850 UT on 21 January 2005 and 0140 UT on 25 January 2005. Four balloons, each carrying an X-ray spectrometer, a Z-axis search coil magnetometer, and a 3-axis electric field instrument providing DC electric field and VLF measurements in 3 frequency bands, were launched from the South African Antarctic Station (SANAE IV). The Southern launches took place at 1400 UT on 17 January, 1309 UT on 19 January, 2115 UT on 20 January, and 0950 UT on 24 January 24 2005. In this paper, we present the preliminary results from the MINIS North and South X-ray data. The first and second Southern payloads observed a rarely-seen phenomenon: gamma-ray line emission from nuclear interactions of solar protons in the Earth's atmosphere. When the solar particles abated, there were numerous opportunities for simultaneous observations of MeV precipitation from multiple
Seto, Keita; Nagatomo, Hideo; Koga, James; Mima, Kunioki
In the near future, the intensity of the ultra-short pulse laser will reach to 1022 W/cm2. When an electron is irradiated by this laser, the electron's behavior is relativistic with significant bremsstrahlung. This radiation from the electron is regarded as the energy loss of electron. Therefore, the electron's motion changes because of the kinetic energy changing. This radiation effect on the charged particle is the self-interaction, called the “radiation reaction” or the “radiation damping”. For this reason, the radiation reaction appears in laser electron interactions with an ultra-short pulse laser whose intensity becomes larger than 1022 W/cm2. In the classical theory, it is described by the Lorentz-Abraham-Dirac (LAD) equation. But, this equation has a mathematical difficulty, which we call the “run-away”. Therefore, there are many methods for avoiding this problem. However, Dirac's viewpoint is brilliant, based on the idea of quantum electrodynamics. We propose a new equation of motion in the quantum theory with radiation reaction in this paper.
Channeling of relativistic laser pulses in underdense plasmas and subsequent electron acceleration
Naseri N.
2013-11-01
Full Text Available This contribution is concerned with the nonlinear behavior of a relativistic laser pulse focused in an underdense plasma and with the subsequent generation of fast electrons. Specifically, we study the interaction of laser pulses having their intensity Iλ2 in the range [1019, 1020] W/cm2 μm2, focused in a plasma of electron density n0 such that the ratio n0/nc lies in the interval [10−3, 2 × 10−2], nc denoting the critical density; the laser pulse power PL exceeds the critical power for laser channeling Pch. The laser-plasma interaction in such conditions is investigated by means of 3D Particle in Cell (PIC simulations. It is observed that the laser front gives rise to the excitation of a surface wave which propagates along the sharp boundaries of the electron free channel created by the laser pulse. The mechanism responsible for the generation of the fast electrons observed in the PIC simulations is then analyzed by means of a test particles code. It is thus found that the fast electrons are generated by the combination of the betatron process and of the acceleration by the surface wave. The maximum electron energy observed in the simulations with Iλ2 = 1020 W/cm2 μm2 and n0/nc = 2 × 10−2 is 350 MeV.
Krauland, C. M.; Wei, M.; Zhang, S.; Santos, J.; Nicolai, P.; Theobald, W.; Kim, J.; Forestier-Colleoni, P.; Beg, F.
2016-10-01
Understanding the transport physics of a relativistic electron beam in various plasma regimes is crucial for many high-energy-density applications, such as fast heating for advanced ICF schemes and ion sources. Most short pulse laser-matter interaction experiments for transport studies have been performed with initially cold targets where the resistivity is far from that in warm dense plasmas. We present three experiments that have been performed on OMEGA EP in order to extend fast electron transport and energy coupling studies in pre-assembled plasmas from different carbon samples. Each experiment has used one 4 ns long pulse UV beam (1014 W/cm2) to drive a shockwave through the target and a 10 ps IR beam (1019 W/cm2) to create an electron beam moving opposite the shock propagation direction. These shots were compared with initially cold target shots without the UV beam. We fielded three different samples including 340 mg/cc CRF foam, vitreous carbon at 1.4 g/cc, and high density carbon at 3.4 g/cc. Electrons were diagnosed via x-ray fluorescence measurements from a buried Cu tracer in the target, as well as bremsstrahlung emission and escaped electrons reaching an electron spectrometer. Proton radiograph was also performed in the foam shots. Details of each experiment, available data and particle-in-cell simulations will be presented. This work is supported by US DOE NLUF Program, Grant Number DE-NA0002728.
Propagation of a laser-driven relativistic electron beam inside a solid dielectric.
Sarkisov, G S; Ivanov, V V; Leblanc, P; Sentoku, Y; Yates, K; Wiewior, P; Chalyy, O; Astanovitskiy, A; Bychenkov, V Yu; Jobe, D; Spielman, R B
2012-09-01
Laser probe diagnostics: shadowgraphy, interferometry, and polarimetry were used for a comprehensive characterization of ionization wave dynamics inside a glass target induced by a laser-driven, relativistic electron beam. Experiments were done using the 50-TW Leopard laser at the University of Nevada, Reno. We show that for a laser flux of ∼2 × 10(18) W/cm2 a hemispherical ionization wave propagates at c/3 for 10 ps and has a smooth electron-density distribution. The maximum free-electron density inside the glass target is ∼2 × 10(19) cm-3, which corresponds to an ionization level of ∼0.1%. Magnetic fields and electric fields do not exceed ∼15 kG and ∼1 MV/cm, respectively. The electron temperature has a hot, ringlike structure with a maximum of ∼0.7 eV. The topology of the interference phase shift shows the signature of the "fountain effect", a narrow electron beam that fans out from the propagation axis and heads back to the target surface. Two-dimensional particle-in-cell (PIC) computer simulations demonstrate radial spreading of fast electrons by self-consistent electrostatic fields driven by laser. The very low ionization observed after the laser heating pulse suggests a fast recombination on the sub-ps time scale.
New determination of the electron's mass.
Beier, Thomas; Häffner, Hartmut; Hermanspahn, Nikolaus; Karshenboim, Savely G; Kluge, H-Jürgen; Quint, Wolfgang; Stahl, Stefan; Verdú, José; Werth, Günther
2002-01-07
A new independent value for the electron's mass in units of the atomic mass unit is presented, m(e) = 0.000 548 579 909 2(4) u. The value is obtained from our recent measurement of the g factor of the electron in (12)C(5+) in combination with the most recent quantum electrodynamical (QED) predictions. In the QED corrections, terms of order alpha(2) were included by a perturbation expansion in Zalpha. Our total precision is three times better than that of the accepted value for the electron's mass.
Gravitationally confined relativistic neutrinos
Vayenas, C. G.; Fokas, A. S.; Grigoriou, D.
2017-09-01
Combining special relativity, the equivalence principle, and Newton’s universal gravitational law with gravitational rather than rest masses, one finds that gravitational interactions between relativistic neutrinos with kinetic energies above 50 MeV are very strong and can lead to the formation of gravitationally confined composite structures with the mass and other properties of hadrons. One may model such structures by considering three neutrinos moving symmetrically on a circular orbit under the influence of their gravitational attraction, and by assuming quantization of their angular momentum, as in the Bohr model of the H atom. The model contains no adjustable parameters and its solution, using a neutrino rest mass of 0.05 eV/c2, leads to composite state radii close to 1 fm and composite state masses close to 1 GeV/c2. Similar models of relativistic rotating electron - neutrino pairs give a mass of 81 GeV/c2, close to that of W bosons. This novel mechanism of generating mass suggests that the Higgs mass generation mechanism can be modeled as a latent gravitational field which gets activated by relativistic neutrinos.
Ni, Binbin; Zou, Zhengyang; Li, Xinlin; Bortnik, Jacob; Xie, Lun; Gu, Xudong
2016-06-01
Using Van Allen Probes Relativistic Electron Proton Telescope (REPT) pitch angle resolved electron flux data from September 2012 to March 2015, we investigate in detail the global occurrence pattern of equatorial (|λ| ≤ 3°) butterfly distribution of outer zone relativistic electrons and its potential correlation with the solar wind dynamic pressure. The statistical results demonstrate that these butterfly distributions occur with the highest occurrence rate ~ 80% at ~ 20-04 magnetic local time (MLT) and L > ~ 5.5 and with the second peak (> ~ 50%) at ~ 11-15 MLT of lower L shells ~ 4.0. They can also extend to L = 3.5 and to other MLT intervals but with the occurrence rates predominantly butterfly distributions are likely to peak between 58° and 79° for L = 4.0 and 5.0 and between 37° and 58° for L = 6.0, regardless of the level of solar wind dynamic pressure. Relativistic electron butterfly distributions at L = 4.0 also exhibit a pronounced day-night asymmetry in response to the Pdyn variations. Compared to the significant L shell and MLT dependence of the global occurrence pattern, outer zone relativistic electron butterfly distributions show much less but still discernable sensitivity to Pdyn, geomagnetic activity level, and electron energy, the full understanding of which requires future attempts of detailed simulations that combine and differentiate underlying physical mechanisms of the geomagnetic field asymmetry and scattering by various magnetospheric waves.
S. W. H. Cowley
2006-03-01
Full Text Available Recent spectroscopic observations of Jupiter's "main oval" auroras indicate that the primary auroral electron beam is routinely accelerated to energies of ~100 keV, and sometimes to several hundred keV, thus approaching the relativistic regime. This suggests the need to re-examine the classic non-relativistic theory of auroral electron acceleration by field-aligned electric fields first derived by Knight (1973, and to extend it to cover relativistic situations. In this paper we examine this problem for the case in which the source population is an isotropic Maxwellian, as also assumed by Knight, and derive exact analytic expressions for the field-aligned current density (number flux and kinetic energy flux of the accelerated population, for arbitrary initial electron temperature, acceleration potential, and field strength beneath the acceleration region. We examine the limiting behaviours of these expressions, their regimes of validity, and their implications for auroral acceleration in planetary magnetospheres (and like astrophysical systems. In particular, we show that for relativistic accelerating potentials, the current density increases as the square of the minimum potential, rather than linearly as in the non-relativistic regime, while the kinetic energy flux then increases as the cube of the potential, rather than as the square.
Zhang, C J; Hua, J F; Xu, X L; Li, F; Pai, C-H; Wan, Y; Wu, Y P; Gu, Y Q; Mori, W B; Joshi, C; Lu, W
2016-07-11
A new method capable of capturing coherent electric field structures propagating at nearly the speed of light in plasma with a time resolution as small as a few femtoseconds is proposed. This method uses a few femtoseconds long relativistic electron bunch to probe the wake produced in a plasma by an intense laser pulse or an ultra-short relativistic charged particle beam. As the probe bunch traverses the wake, its momentum is modulated by the electric field of the wake, leading to a density variation of the probe after free-space propagation. This variation of probe density produces a snapshot of the wake that can directly give many useful information of the wake structure and its evolution. Furthermore, this snapshot allows detailed mapping of the longitudinal and transverse components of the wakefield. We develop a theoretical model for field reconstruction and verify it using 3-dimensional particle-in-cell (PIC) simulations. This model can accurately reconstruct the wakefield structure in the linear regime, and it can also qualitatively map the major features of nonlinear wakes. The capturing of the injection in a nonlinear wake is demonstrated through 3D PIC simulations as an example of the application of this new method.
Zhang, C J; Xu, X L; Li, F; Pai, C -H; Wan, Y; Wu, Y P; Gu, Y Q; Mori, W B; Joshi, C; Lu, W
2016-01-01
A new method capable of capturing coherent electric field structures propagating at nearly the speed of light in plasma with a time resolution as small as a few femtoseconds is proposed. This method uses a few femtoseconds long relativistic electron bunch to probe the wake produced in a plasma by an intense laser pulse or an ultra-short relativistic charged particle beam. As the probe bunch traverses the wake, its momentum is modulated by the electric field of the wake, leading to a density variation of the probe after free-space propagation. This variation of probe density produces a snapshot of the wake that can directly give many useful information of the wake structure and its evolution. Furthermore, this snapshot allows detailed mapping of the longitudinal and transverse components of the wakefield. We develop a theoretical model for field reconstruction and verify it using 3-dimensional particle-in-cell (PIC) simulations. This model can accurately reconstruct the wakefield structure in the linear regime...
Simulation of Ultra-Relativistic Electrons and Positrons Channeling in Crystals with MBN Explorer
Sushko, Gennady B; Solov'yov, Ilia A; Korol, Andrei V; Greiner, Walter; Solov'yov, Andrey V
2013-01-01
A newly developed code, implemented as a part of the \\MBNExplorer package \\cite{MBN_ExplorerPaper,MBN_ExplorerSite} to simulate trajectories of an ultra-relativistic projectile in a crystalline medium, is presented. The motion of a projectile is treated classically by integrating the relativistic equations of motion with account for the interaction between the projectile and crystal atoms. The probabilistic element is introduced by a random choice of transverse coordinates and velocities of the projectile at the crystal entrance as well as by accounting for the random positions of the atoms due to thermal vibrations. The simulated trajectories are used for numerical analysis of the emitted radiation. Initial approbation and verification of the code have been carried out by simulating the trajectories and calculating the radiation emitted by $\\E=6.7$ GeV and $\\E=855$ MeV electrons and positrons in oriented Si(110) crystal and in amorphous silicon. The calculated spectra are compared with the experimental data ...
Simulation of ultra-relativistic electrons and positrons channeling in crystals with MBN EXPLORER
Sushko, Gennady B.; Bezchastnov, Victor G.; Solov'yov, Ilia A.; Korol, Andrei V.; Greiner, Walter; Solov'yov, Andrey V.
2013-11-01
A newly developed code, implemented as a part of the MBN EXPLORER package (Solov'yov et al., 2012; http://www.mbnexplorer.com/, 2012) [1,2] to simulate trajectories of an ultra-relativistic projectile in a crystalline medium, is presented. The motion of a projectile is treated classically by integrating the relativistic equations of motion with account for the interaction between the projectile and crystal atoms. The probabilistic element is introduced by a random choice of transverse coordinates and velocities of the projectile at the crystal entrance as well as by accounting for the random positions of the atoms due to thermal vibrations. The simulated trajectories are used for numerical analysis of the emitted radiation. Initial approbation and verification of the code have been carried out by simulating the trajectories and calculating the radiation emitted by ε=6.7 GeV and ε=855 MeV electrons and positrons in oriented Si(110) crystal and in amorphous silicon. The calculated spectra are compared with the experimental data and with predictions of the Bethe-Heitler theory for the amorphous environment.
Zhang, C. J.; Hua, J. F.; Xu, X. L.; Li, F.; Pai, C.-H.; Wan, Y.; Wu, Y. P.; Gu, Y. Q.; Mori, W. B.; Joshi, C.; Lu, W.
2016-07-01
A new method capable of capturing coherent electric field structures propagating at nearly the speed of light in plasma with a time resolution as small as a few femtoseconds is proposed. This method uses a few femtoseconds long relativistic electron bunch to probe the wake produced in a plasma by an intense laser pulse or an ultra-short relativistic charged particle beam. As the probe bunch traverses the wake, its momentum is modulated by the electric field of the wake, leading to a density variation of the probe after free-space propagation. This variation of probe density produces a snapshot of the wake that can directly give many useful information of the wake structure and its evolution. Furthermore, this snapshot allows detailed mapping of the longitudinal and transverse components of the wakefield. We develop a theoretical model for field reconstruction and verify it using 3-dimensional particle-in-cell (PIC) simulations. This model can accurately reconstruct the wakefield structure in the linear regime, and it can also qualitatively map the major features of nonlinear wakes. The capturing of the injection in a nonlinear wake is demonstrated through 3D PIC simulations as an example of the application of this new method.
Grassi, A.; Grech, M.; Amiranoff, F.; Pegoraro, F.; Macchi, A.; Riconda, C.
2017-02-01
The Weibel instability driven by two symmetric counterstreaming relativistic electron plasmas, also referred to as current-filamentation instability, is studied in a constant and uniform external magnetic field aligned with the plasma flows. Both the linear and nonlinear stages of the instability are investigated using analytical modeling and particle-in-cell simulations. While previous studies have already described the stabilizing effect of the magnetic field, we show here that the saturation stage is only weakly affected. The different mechanisms responsible for the saturation are discussed in detail in the relativistic cold fluid framework considering a single unstable mode. The application of an external field leads to a slight increase of the saturation level for large wavelengths, while it does not affect the small wavelengths. Multimode and temperature effects are then investigated. While at high temperature the saturation level is independent of the external magnetic field, at low but finite temperature the competition between different modes in the presence of an external magnetic field leads to a saturation level lower with respect to the unmagnetized case.
Thomson backscattering from laser generated, relativistically moving high-density electron layers
Paz, Athena E; Rödel, Christian; Schnell, Michael; Jäckel, Oliver; Kaluza, Malte C; Paulus, Gerhard G
2012-01-01
We show experimentally that XUV radiation is produced when a laser pulse is Thomson backscattered from sheets of relativistic electrons which are formed at the rear-surface of a foil irradiated on its front side by a high-intensity laser. An all-optical setup is realized using the Jena Titanium:Sapphire TW laser system (JETI). The main pulse is split into two pulses: one to accelerate electrons from thin aluminum foil targets to energies of the order of some MeV and the other, counterpropagating probe pulse is Thomson-backscattered off these electrons when they exit the target rear side. The process produced photons within a wide spectral range of some tens of eV as a result of the broad electron energy distribution. The highest scattering intensity is observed when the probe pulse arrives at the target rear surface 100 fs after the irradiation of the target front side by the pump pulse, corresponding to the maximum flux of hot electrons at the interaction region. These results can provide time-resolved infor...
On quantum effects in spontaneous emission by a relativistic electron beam in an undulator
Geloni, Gianluca [European XFEL GmbH, Hamburg (Germany); Kocharyan, Vitali; Saldin, Evgeni [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)
2012-02-15
Robb and Bonifacio (2011) claimed that a previously neglected quantum effect results in noticeable changes in the evolution of the energy distribution associated with spontaneous emission in long undulators. They revisited theoretical models used to describe the emission of radiation by relativistic electrons as a continuous diffusive process, and claimed that in the asymptotic limit for a large number of undulator periods the evolution of the electron energy distribution occurs as discrete energy groups according to Poisson distribution. We show that these novel results have no physical sense, because they are based on a one-dimensional model of spontaneous emission and assume that electrons are sheets of charge. However, electrons are point-like particles and, as is well-known, the bandwidth of the angular-integrated spectrum of undulator radiation is independent of the number of undulator periods. If we determine the evolution of the energy distribution using a three-dimensional theory we find the well-known results consistent with a continuous diffusive process. The additional pedagogical purpose of this paper is to review how quantum diffusion of electron energy in an undulator with small undulator parameter can be simply analyzed using the Thomson cross-section expression, unlike the conventional treatment based on the expression for the Lienard-Wiechert fields. (orig.)
Relativistic electron beam interaction and $K_{\\alpha}$-generation in solid targets
Fill, E; Eder, D; Eidmann, K; Saemann, A
1999-01-01
When fs laser pulses interact with solid surfaces at intensities I lambda /sup 2/ >10/sup 18/ W/cm/sup 2/ mu m/sup 2/, collimated relativistic electron beams are generated. These electrons can be used for producing intense X-radiation (bremsstrahlung or K/sub alpha /) for pumping an innershell X-ray laser. The basic concept of such a laser involves the propagation of the electron beam in a material which converts electron energy into appropriate pump photons. Using the ATLAS titanium-sapphire laser at Max-Planck-Institut fur Quantenoptik, we investigate the generation of hot electrons and of characteristic radiation in copper. The laser (200 mJ/130 fs) is focused by means of an off-axis parabola to a diameter of about 10 mu m. By varying the position of the focus, we measure the copper K/sub alpha /-yield as a function of intensity in a range from 10/sup 15/ to 2 x 10/sup 18/ W/cm/sup 2/ while keeping the laser pulse energy constant. Surprisingly, the highest emission is obtained at an intensity of about 10/s...
Mass Customization in the electronics industry
Hvam, Lars
2006-01-01
American Power Conversion (APC), a company in the electronics industry, has used the principles of mass customisation to achieve major improvements in its efficiency and performance. APC sells, designs, produces, delivers, and installs large complex infrastructure systems for data centres...
Kozyreva, O.; Pilipenko, V.; Engebretson, M. J.; Yumoto, K.; Watermann, J.; Romanova, N.
2007-04-01
A new ULF wave index, characterizing the turbulent level of the geomagnetic field, has been calculated and applied to the analysis of relativistic electron enhancements during space weather events in March-May 1994 and September 1999. This global wave index has been produced from the INTERMAGNET, MACCS, CPMN, and Greenland dense magnetometer arrays in the northern hemisphere. A similar ULF wave index has been calculated using magnetometer data from geostationary (GOES) and interplanetary (Wind, ACE) satellites. During the periods analyzed several magnetic storms occurred, and several significant increases of relativistic electron flux up to 2-3 orders of magnitude were detected by geostationary monitors. However, these electron enhancements were not directly related to the intensity of magnetic storms. Instead, they correlated well with intervals of elevated ULF wave index, caused by the occurrence of intense Pc5 pulsations in the magnetosphere. This comparison confirmed earlier results showing the importance of magnetospheric ULF turbulence in energizing relativistic electrons. In addition to relativistic electron energization, a wide range of space physics and geophysics studies will benefit from the introduction of the ULF wave index. The ULF index database is freely available via anonymous FTP for all interested researchers for further validation and statistical studies.
On relativistic motion of a pair of particles having opposite signs of masses
Ivanov, Pavel
2012-01-01
(abbreviated) In this note we consider, in a weak-field limit, a relativistic linear motion of two particles with opposite signs of masses having a small difference between their absolute values $m_{1,2}=\\pm (\\mu\\pm \\Delta \\mu) $, $\\mu > 0$, $|\\Delta \\mu | \\ll \\mu$ and a small difference between their velocities. Assuming that the weak-field limit holds and the dynamical system is conservative an elementary treatment of the problem based on the laws of energy and momentum conservation shows that the system can be accelerated indefinitely, or attain very large asymptotic values of the Lorentz factor $\\gamma$. The system experiences indefinite acceleration when its energy-momentum vector is null and the mass difference $\\Delta \\mu \\le 0$. When modulus of the square of the norm of the energy-momentum vector, $|N^2|$, is sufficiently small the system can be accelerated to very large $\\gamma \\propto |N^2|^{-1}$. It is stressed that when only leading terms in the ratio of a characteristic gravitational radius to th...
Evaluating the Role and Effects of Precipitation on Relativistic Electron Losses during Storms
Chen, Y.; Fu, X.
2016-12-01
Theoretic studies have suggested that during storm times various waves (e.g., whistler-mode chorus and electromagnetic ion cyclotron waves) can cause significant precipitation of relativistic ( MeV) electrons that are originally trapped inside the outer radiation belt. However, the role of precipitation and its quantitative contribution to the losses of outer-belt electrons remain open questions. In this study, we tackle these questions by systemically examining the latest wave and electron in-situ, simultaneous observations made at different altitudes by Van Allen Probes from near equator, NOAA POES at low Earth orbits near/across electron loss cone, and BARREL under the mesosphere. After calibrating with DEMTER observations, we first confirm and quantify the response of POES MEPED proton channels to MeV electrons. Next, we identify a list of precipitation events from BARREL and POES measurements, examine the temporal adn spatial relation between the two data sets, and estimate the intensities of electron precipitation with ascertained uncertainties. Then, from Van Allen Probes data, we select another list of dropout events during storms. By cross checking the above two lists, we are able to determine the causal relation between precipitation and dropouts through individual case as well as statistical studies so as to quantify the contributions from precipitation. This study mainly focuses on the relatively small L-shells with positive phase space density radial gradient in order to alleviate the impacts from outward radial diffusion and adiabatic effects. Based upon the recent discovery of cross-energy cross-pitch angle coherence, we pay particular attention to the cross-term diffusions which may account for the extra "loss" needed by observed MeV electron dropouts. Results from this observational study will advance our knowledge on the loss mechanism of outer-belt electrons, and thus lay down another stepping stone towards high-fidelity physics-based models for
Relativistic mergers of black hole binaries have large, similar masses, low spins and are circular
Amaro-Seoane, Pau; Chen, Xian
2016-05-01
Gravitational waves are a prediction of general relativity, and with ground-based detectors now running in their advanced configuration, we will soon be able to measure them directly for the first time. Binaries of stellar-mass black holes are among the most interesting sources for these detectors. Unfortunately, the many different parameters associated with the problem make it difficult to promptly produce a large set of waveforms for the search in the data stream. To reduce the number of templates to develop, one must restrict some of the physical parameters to a certain range of values predicted by either (electromagnetic) observations or theoretical modelling. In this work, we show that `hyperstellar' black holes (HSBs) with masses 30 ≲ MBH/M⊙ ≲ 100, i.e black holes significantly larger than the nominal 10 M⊙, will have an associated low value for the spin, i.e. a < 0.5. We prove that this is true regardless of the formation channel, and that when two HSBs build a binary, each of the spin magnitudes is also low, and the binary members have similar masses. We also address the distribution of the eccentricities of HSB binaries in dense stellar systems using a large suite of three-body scattering experiments that include binary-single interactions and long-lived hierarchical systems with a highly accurate integrator, including relativistic corrections up to O(1/c^5). We find that most sources in the detector band will have nearly zero eccentricities. This correlation between large, similar masses, low spin and low eccentricity will help to accelerate the searches for gravitational-wave signals.
Baryons in the relativistic jets of the stellar-mass black hole candidate 4U 1630-47
Trigo, María Díaz; Migliari, Simone; Broderick, Jess W; Tzioumis, Tasso
2013-01-01
Accreting black holes are known to power relativistic jets, both in stellar-mass binary systems and at the centres of galaxies. The power carried away by the jets, and hence the feedback they provide to their surroundings, depends strongly on their composition. Jets containing a baryonic component should carry significantly more energy than electron-positron jets. While energetic considerations and circular polarisation measurements have provided conflicting circumstantial evidence for the presence or absence of baryons, the only system in which baryons have been unequivocally detected in the jets is the X-ray binary SS 433. Here we report the detection of Doppler-shifted X-ray emission lines from a more typical black hole candidate X-ray binary, 4U1630-47, coincident with the reappearance of radio emission from the jets of the source. We argue that these lines arise in a jet with velocity 0.66c, thereby establishing the presence of baryons in the jet. Such baryonic jets are more likely to be powered by the a...
Double lepton pair production with electron capture in relativistic heavy--ion collisions
Artemyev, A N; Surzhykov, A
2014-01-01
We present a theoretical study of a double lepton pair production in ultra--relativistic collision between two bare ions. Special emphasis is placed to processes in which creation of (at least one) $e^+ e^-$ pair is accompanied by the capture of an electron into a bound ionic state. To evaluate the probability and cross section of these processes we employ two approaches based on (i) the first--order perturbation theory and multipole expansion of Dirac wavefunctions, and (ii) the equivalent photon approximation. With the help of such approaches, detailed calculations are made for the creation of two bound--free $e^+ e^-$ pairs as well as of bound--free $e^+ e^-$ and free--free $\\mu^+ \\mu^-$ pairs in collisions of bare lead ions Pb$^{82+}$. The results of the calculations indicate that observation of the double lepton processes may become feasible at the LHC facility.
Optical response of relativistic electrons in the polar BiTeI semiconductor.
Lee, J S; Schober, G A H; Bahramy, M S; Murakawa, H; Onose, Y; Arita, R; Nagaosa, N; Tokura, Y
2011-09-09
The transitions between the spin-split bands by spin-orbit interaction are relevant to many novel phenomena such as the resonant dynamical magnetoelectric effect and the spin Hall effect. We perform optical spectroscopy measurements combined with first-principles calculations to study these transitions in the recently discovered giant bulk Rashba spin-splitting system BiTeI. Several novel features are observed in the optical spectra of the material including a sharp edge singularity due to the reduced dimensionality of the joint density of states and a systematic doping dependence of the intraband transitions between the Rashba-split branches. These confirm the bulk nature of the Rashba-type splitting in BiTeI and manifest the relativistic nature of the electron dynamics in a solid.
On the Infrared Problem for the Dressed Non-Relativistic Electron in a Magnetic Field
Amour, Laurent; Grebert, Benoit; Guillot, Jean-Claude
2008-01-01
We consider a non-relativistic electron interacting with a classical magnetic field pointing along the $x_3$-axis and with a quantized electromagnetic field. The system is translation invariant in the $x_3$-direction and we consider the reduced Hamiltonian $H(P_3)$ associated with the total momentum $P_3$ along the $x_3$-axis. For a fixed momentum $P_3$ sufficiently small, we prove that $H(P_3)$ has a ground state in the Fock representation if and only if $E'(P_3)=0$, where $P_3 \\mapsto E'(P_3)$ is the derivative of the map $P_3 \\mapsto E(P_3) = \\inf \\sigma (H(P_3))$. If $E'(P_3) \
Design study of primary ion provider for relativistic heavy ion collider electron beam ion source.
Kondo, K; Kanesue, T; Tamura, J; Okamura, M
2010-02-01
Brookhaven National Laboratory has developed the new preinjector system, electron beam ion source (EBIS) for relativistic heavy ion collider (RHIC) and National Aeronautics and Space Administration Space Radiation Laboratory. Design of primary ion provider is an essential problem since it is required to supply beams with different ion species to multiple users simultaneously. The laser ion source with a defocused laser can provide a low charge state and low emittance ion beam, and is a candidate for the primary ion source for RHIC-EBIS. We show a suitable design with appropriate drift length and solenoid, which helps to keep sufficient total charge number with longer pulse length. The whole design of primary ion source, as well as optics arrangement, solid targets configuration and heating about target, is presented.
Tanjia, Fatema; Fedele, Renato; Shukla, P K; Jovanovic, Dusan
2011-01-01
A numerical analysis of the self-interaction induced by a relativistic electron/positron beam in the presence of an intense external longitudinal magnetic field in plasmas is carried out. Within the context of the Plasma Wake Field theory in the overdense regime, the transverse beam-plasma dynamics is described by a quantumlike Zakharov system of equations in the long beam limit provided by the Thermal Wave Model. In the limiting case of beam spot size much larger than the plasma wavelength, the Zakharov system is reduced to a 2D Gross-Pitaevskii-type equation, where the trap potential well is due to the external magnetic field. Vortices, "beam halos" and nonlinear coherent states (2D solitons) are predicted.
Bailly-Grandvaux, M; Bellei, C; Forestier-Colleoni, P; Fujioka, S; Giuffrida, L; Honrubia, J J; Batani, D; Bouillaud, R; Chevrot, M; Cross, J E; Crowston, R; Dorard, S; Dubois, J -L; Ehret, M; Gregori, G; Hulin, S; Kojima, S; Loyez, E; Marques, J -R; Morace, A; Nicolai, Ph; Roth, M; Sakata, S; Schaumann, G; Serres, F; Servel, J; Tikhonchuk, V T; Woolsey, N; Zhang, Z
2016-01-01
High-energy-density flows through dense matter are needed for effective progress in the production of laser-driven intense sources of energetic particles and radiation, in driving matter to extreme temperatures creating state regimes relevant for planetary or stellar science as yet inaccessible at the laboratory scale, or in achieving high-gain laser-driven thermonuclear fusion. When interacting at the surface of dense (opaque) targets, intense lasers accelerate relativistic electron beams which transport a significant fraction of the laser energy into the target depth. However, the overall laser-to-target coupling efficiency is impaired by the large divergence of the electron beam, intrinsic to the laser-plasma interaction. By imposing a longitudinal 600T laser-driven magnetic-field, our experimental results show guided >10MA-current of MeV-electrons in solid matter. Due to the applied magnetic field, the transported energy-density and the peak background electron temperature at the 60micron-thick targets re...
Kovács, Attila
2017-03-17
Actinide trioxide (AnO3, An = U, Np, Pu, Am, Cm) molecules have been investigated by relativistic multireference quantum chemical calculations with the goal to elucidate their electronic structures. The molecular geometries of the ground and selected excited electronic states have been optimized at the spin-orbit-free complete active space second-order perturbation theory (SF-CASPT2) level. The low-lying vertical excitation states have been computed and characterized by CASPT2 calculations taking into account spin-orbit coupling. The reason for the considerable lengthening of the equatorial An-O bond in AmO3 and CmO3 with respect to the other trioxides has been analyzed on the basis of valence molecular orbitals of the SF ground electronic states. For the bond in question a singly occupied π orbital has been identified, this orbital is doubly occupied in the other (An = U, Np, Pu) trioxides. The clarified electronic structures of the investigated AnO3 molecules confirmed the pentavalent character of Am and Cm in their trioxides in contrast to the hexavalent character of U, Np, and Pu.
1994-01-01
The NATO Advanced Study Institute (ASI) on "R@lativistic and Electron Correlation Effects in Molecules and Solids", co-sponsored by Simon Fraser University (SFU) and the Natural Sciences and Engineering Research Council of Canada (NSERC) was held Aug 10- 21, 1992 at the University of British Columbia (UBC), Vancouver, Canada. A total of 90 lecturers and students with backgrounds in Chemistry, Physics, Mathematics and various interdisciplinary subjects attended the ASI. In my proposal submitted to NATO for financial support for this ASI, I pointed out that a NATO ASI on the effects of relativity in many-electron systems was held ten years ago, [See G.L. Malli, (ed) Relativistic Effects in Atoms, Molecules and Solids, Plenum Press, Vol B87, New York, 1983]. Moreover, at a NATO Advanced Research Workshop (ARW) on advanced methods for molecular electronic structure "an assessment of state-of the-art of Electron Correlation ... " was carried out [see C.E. Dykstra, (ed), Advanced Theories and Computational Approa...
Souza, V. M. C. E. S.; Vieira, L.; Alves, L. R.; Da Silva, L. A.; Koga, D.; Sibeck, D. G.; Walsh, B.; Kanekal, S. G.; Silveira, M. D.; Medeiros, C.; Mendes, O., Jr.; Marchezi, J.; Rockenbach, M.; Jauer, P. R.; Gonzalez, W.; Baker, D. N.
2015-12-01
A myriad of physical phenomena occur in the inner magnetosphere, in particular at the Earth's radiation belts, which can be a result of the combination of both internal and external processes. However, the connection between physical processes occurring deep within the magnetosphere and external interplanetary drivers it is not yet well understood. In this work we investigate whether a selected set of interplanetary structures affect the local time distribution of three different classes of high energy electron pitch angle distributions (PADs), namely normal, isotropic, and butterfly. We split this work into two parts: initially we focus on the methodology used which employs a Self-Organized Feature Map (SOFM) neural network for identifying different classes of electron PAD shapes in the Van Allen Probes' Relativistic Electron Proton Telescope (REPT) data. The algorithm can categorize the input data into an arbitrary number of classes from which three of them appears the most: normal, isotropic and butterfly. Other classes which are related with these three also emerge and deserve to be addressed in detail in future works. We also discuss the uncertainties of the algorithm. Then, we move to the second part where we describe in details the criteria used for selecting the interplanetary events, and also try to investigate the relation between key parameters characterizing such interplanetary structures and the local time distributions of electron PAD shapes.
Effect of EMIC Wave Normal Angle Distribution on Relativistic Electron Scattering in Outer RB
Khazanov, G. V.; Gamayunov, K. V.
2007-01-01
We present the equatorial and bounce average pitch angle diffusion coefficients for scattering of relativistic electrons by the H+ mode of EMIC waves. Both the model (prescribed) and self consistent distributions over the wave normal angle are considered. The main results of our calculation can be summarized as follows: First, in comparison with field aligned waves, the intermediate and highly oblique waves reduce the pitch angle range subject to diffusion, and strongly suppress the scattering rate for low energy electrons (E less than 2 MeV). Second, for electron energies greater than 5 MeV, the |n| = 1 resonances operate only in a narrow region at large pitch-angles, and despite their greatest contribution in case of field aligned waves, cannot cause electron diffusion into the loss cone. For those energies, oblique waves at |n| greater than 1 resonances are more effective, extending the range of pitch angle diffusion down to the loss cone boundary, and increasing diffusion at small pitch angles by orders of magnitude.
Electron mass stopping power in H2
Fursa, Dmitry V.; Zammit, Mark C.; Threlfall, Robert L.; Savage, Jeremy S.; Bray, Igor
2017-08-01
Calculations of electron mass stopping power (SP) of electrons in H2 have been performed using the convergent close-coupling method for incident electron energies up to 2000 eV. Convergence of the calculated SP has been established by increasing the size of the close-coupling expansion from 9 to 491 states. Good agreement was found with the SP measurements of Munoz et al. [Chem. Phys. Lett. 433, 253 (2007), 10.1016/j.cplett.2006.10.114].
Duskside relativistic electron precipitation as measured by SAMPEX: A statistical survey
Comess, Max D.; Smith, David M.; Selesnick, Richard S.; Millan, Robyn M.; Sample, John G.
2013-08-01
Evidence for duskside relativistic electron precipitation (DREP) within the Earth's outer radiation belt has historically been seen in a few sets of high altitude balloon data (MAXIS, MINIS, INTERBOA), and in satellite data. We present statistical evidence that the relativistic electron precipitation events from the outer radiation belt with e-folding energies > 0.5 MeV are concentrated in the dusk-to-midnight sector, based on a survey of data collected by the SAMPEX satellite from 1992 to 2004. A correlation between spectral hardness and duskside MLT is observed in our sample, the largest studied to date. Out of 9380 precipitation events within the bounce loss cone, 1048 are observed to have exponentially falling spectra with e-folding energies above 0.5 MeV ("hard events") and 1648 events below 0.2 MeV. Of the hard events, 81% occur within 12 h to 24 h MLT, compared to only 37% of events having e-folding energies below 0.2 MeV. With microbursts removed from this softer population the percentage of duskside events rises to 46%. The hard events occur at slightly elevated levels of geomagnetic activity (Ap and Dst) relative to softer nonmicroburst events, but these correlations are much weaker than for microbursts. The hard events are observed to peak in occurrence at L ~ 5.5, significantly higher than nonmicroburst softer events, even though the opposite might be expected from compression of the magnetosphere due to the more negative average Dst of the hard events. The hard events are most prevalent during the declining phase of the 11 year solar cycle.
Ultra-High-Contrast Laser Acceleration of Relativistic Electrons in Solid Targets
Higginson, Drew Pitney [Univ. of California, San Diego, CA (United States)
2013-01-01
The cone-guided fast ignition approach to Inertial Con nement Fusion requires laser-accelerated relativistic electrons to deposit kilojoules of energy within an imploded fuel core to initiate fusion burn. One obstacle to coupling electron energy into the core is the ablation of material, known as preplasma, by laser energy proceeding nanoseconds prior to the main pulse. This causes the laser-absorption surface to be pushed back hundreds of microns from the initial target surface; thus increasing the distance that electrons must travel to reach the imploded core. Previous experiments have shown an order of magnitude decrease in coupling into surrogate targets when intentionally increasing the amount of preplasma. Additionally, for electrons to deposit energy within the core, they should have kinetic energies on the order of a few MeV, as less energetic electrons will be stopped prior to the core and more energetic electrons will pass through the core without depositing much energy. Thus a quantitative understanding of the electron energy spectrum and how it responds to varied laser parameters is paramount for fast ignition. For the rst time, this dissertation quantitatively investigates the acceleration of electrons using an ultra-high-contrast laser. Ultra-high-contrast lasers reduce the laser energy that reaches the target prior to the main pulse; drastically reducing the amount of preplasma. Experiments were performed in a cone-wire geometry relevant to fast ignition. These experiments irradiated the inner-tip of a Au cone with the laser and observed electrons that passed through a Cu wire attached to the outer-tip of the cone. The total emission of K x-rays is used as a diagnostic to infer the electron energy coupled into the wire. Imaging the x-ray emission allowed an e ective path-length of electrons within the wire to be determined, which constrained the electron energy spectrum. Experiments were carried out on the ultra-high-contrast Trident laser at Los
Relativistic electron beams from cathodes at 1 GV/m gradient
Srinivasan-Rao, T.; Smedley, J.; Schill, J.
1998-05-01
In the past decade, there has been extensive research in the development of low emittance, high brightness electron injectors for linear collider and free electron laser applications. RF injectors with a few nC charge in a few ps, with an emittance of {approximately}1--5 {pi}mm mrad are operational in a number of facilities. In these devices, a laser beam irradiates a photocathode embedded in an RF cavity. The photoelectrons released by the laser are immediately accelerated to relativistic velocities, thereby reducing the space charge effects. The frequency of the RF and the design of the cavity are chosen to minimize the RF and space charge effects on the electron bunch so that low emittance, high brightness electron beam could be generated. Minimization of RF effects on emittnce growth require a low RF frequency while minimizing the space charge effects require high field and hence high RF frequency. The design is hence a compromise between these two conflicting requirements. Some of these limitations could be overcome by using a large pulsed electric field at the cathode rather than a RF field. The duration of the pulsed field should be chosen so that it is longer than the electron bunch length and the transit time in the accelerating region, but short enough to avoid breakdown problems. Development of a high brightness electron source using this scheme requires a pulse generator, a laser pulse of sufficient energy to trigger and synchronize the electrical pulses, and a short laser pulse to irradiate the photocathode and generate electron pulses to be accelerated. The designs of these components are described.
Shokri, B. [Physics Department and Laser-Plasma Research Institute of Shahid Beheshti University, Tehran (Iran, Islamic Republic of) and Institute for Studies in Theoretical Physics and Mathematics, P.O. Box 19395-1795, Tehran (Iran, Islamic Republic of)]. E-mail: b-shokri@cc.sbu.ac.ir; Khorashadizadeh, S.M. [Physics Department of Shahid Beheshti University, Tehran (Iran, Islamic Republic of); Physics Department of Birjand University, Birjand (Iran, Islamic Republic of)
2005-09-19
The possibility of the dissipative instability of a relativistic electron beam streaming near a conducting medium is investigated. The development of this dissipative beam instability through the surface wave excitation slightly disturbs the beam leading to the slightly heating of the conducting medium.
Pokhotelov, D.; Rae, I. J.; Murphy, K. R.; Mann, I. R.
2016-12-01
Electromagnetic ultralow-frequency (ULF) waves are known to play a substantial role in radial transport, acceleration, and loss of relativistic particles trapped in the Earth's outer radiation belt. Using in situ observations by multiple spacecraft operating in the vicinity of outer radiation belts, we analyze the temporal and spatial behavior of ULF waves throughout the geomagnetic storm of 8-9 October 2012 and compare with the dynamics of relativistic electron fluxes on board the twin Van Allen Probes spacecraft. The analysis shows that the relativistic electron fluxes reduce from their prestorm levels during the first phase of the storm and rapidly increase during the second phase of the storm. We demonstrate that the behavior of ULF wave power changes throughout the storm, from ULF oscillations being a mixture of compressional and shear magnetic components during the first phase of the storm to ULF oscillations being dominated by transverse (shear) components during the second phase. We analyze the parameters of ULF-driven radial diffusion throughout the storm and compare the observed diffusion coefficients with their statistical averages. We demonstrate that the observed diffusion coefficients are strong enough to impact the redistribution of relativistic electron fluxes from and to the outer boundary of radiation belts and the diffusion might influence the effects of any local electron acceleration by transporting fluxes inward or outward according to phase space density gradients.
Ahmad, Ali [National Centre for Physics, Shahdara Valley Road, Islamabad (Pakistan); Masood, W. [National Centre for Physics, Shahdara Valley Road, Islamabad (Pakistan); COMSATS Institute of Information Technology, Park Road, Chak Shahzad, Islamabad (Pakistan)
2016-05-15
Linear and nonlinear electrostatic ion acoustic waves in a weakly relativistic magnetorotating plasma in the presence of non-Maxwellian electrons and warm ions have been examined. The system under consideration has yielded two solutions, namely, the fast and slow acoustic modes which have been observed to depend on the streaming velocity, ion to electron temperature ratio, and the nonthermality parameter of the non-Maxwellian electrons. Using the multiple time scale analysis, we have derived the three dimensional nonlinear Zakharov–Kuznetsov equation and also presented its solution. Both compressive and rarefactive solitary structures have been found in consonance with the satellite observations. It has been observed that although the linear dispersion relation gives both fast and slow ion acoustic waves, the solitary structures form only for the fast acoustic mode. The dependence of the characteristics of the solitary structures on several plasma parameters has also been explored. The present investigation may be beneficial to understanding the rotating plasma environments such as those found in the planetary magnetospheres of Saturn and Jupiter.
Stopping of a relativistic electron beam in a plasma irradiated by an intense laser field
Nersisyan, Hrachya B
2014-01-01
The effects of a radiation field (RF) on the interaction process of a relativistic electron beam (REB) with an electron plasma are investigated. The stopping power of the test electron averaged with a period of the RF has been calculated assuming an underdense plasma, $\\omega_{0} >\\omega_{p}$, where $\\omega_{0}$ is the frequency of the RF and $\\omega_{p}$ is the plasma frequency. In order to highlight the effect of the radiation field we present a comparison of our analytical and numerical results obtained for nonzero RF with those for vanishing RF. In particular, it has been shown that the weak RF increases the mean energy loss for small angles between the velocity of the REB and the direction of polarization of the RF while decreasing it at large angles. Furthermore, the relative deviation of the energy loss from the field-free value is strongly reduced with increasing the beam energy. Special case of the parallel orientation of the polarization of the RF with respect to the beam velocity has been also cons...
Cooling of relativistic electron beams in intense laser pulses: Chirps and radiation
Yoffe, S.R., E-mail: sam.yoffe@strath.ac.uk; Noble, A., E-mail: adam.noble@strath.ac.uk; Macleod, A.J., E-mail: alexander.macleod@strath.ac.uk; Jaroszynski, D.A., E-mail: d.a.jaroszynski@strath.ac.uk
2016-09-01
Next-generation high-power laser facilities (such as the Extreme Light Infrastructure) will provide unprecedented field intensities, and will allow us to probe qualitatively new physical regimes for the first time. One of the important fundamental questions which will be addressed is particle dynamics when radiation reaction and quantum effects play a significant role. Classical theories of radiation reaction predict beam cooling in the interaction of a relativistic electron bunch and a high-intensity laser pulse, with final-state properties only dependent on the laser fluence. The observed quantum suppression of this cooling instead exhibits a dependence on the laser intensity directly. This offers the potential for final-state properties to be modified or even controlled by tailoring the intensity profile of the laser pulse. In addition to beam properties, quantum effects will be manifest in the emitted radiation spectra, which could be manipulated for use as radiation sources. We compare predictions made by classical, quasi-classical and stochastic theories of radiation reaction, and investigate the influence of chirped laser pulses on the observed radiation spectra. - Highlights: • Classical theories of radiation reaction predict electron beam cooling in high fields. • Quantum effects lead to a reduction in electron beam cooling. • Quasi-classical model agrees with predictions from a single-emission stochastic model. • Negative frequency chirp found to increase photon emission, but not maximum energy.
Shukla, Chandrasekhar; Das, Amita, E-mail: amita@ipr.res.in [Institute for Plasma Research, Bhat, Gandhinagar 382428 (India); Patel, Kartik [Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India)
2015-11-15
Relativistic electron beam propagation in plasma is fraught with several micro instabilities like two stream, filamentation, etc., in plasma. This results in severe limitation of the electron transport through a plasma medium. Recently, however, there has been an experimental demonstration of improved transport of Mega Ampere of electron currents (generated by the interaction of intense laser with solid target) in a carbon nanotube structured solid target [G. Chatterjee et al., Phys. Rev. Lett. 108, 235005 (2012)]. This then suggests that the inhomogeneous plasma (created by the ionization of carbon nanotube structured target) helps in containing the growth of the beam plasma instabilities. This manuscript addresses this issue with the help of a detailed analytical study and 2-D Particle-In-Cell simulations. The study conclusively demonstrates that the growth rate of the dominant instability in the 2-D geometry decreases when the plasma density is chosen to be inhomogeneous, provided the scale length 1/k{sub s} of the inhomogeneous plasma is less than the typical plasma skin depth (c/ω{sub 0}) scale. At such small scale lengths channelization of currents is also observed in simulation.
Melzani, Mickaël; Folini, Doris; Winisdoerffer, Christophe; Favre, Jean M
2014-01-01
Collisionless magnetic reconnection is a prime candidate to account for flare-like or steady emission, outflow launching, or plasma heating, in a variety of high-energy astrophysical objects, including ones with relativistic ion-electron plasmas. But the fate of the initial magnetic energy in a reconnection event remains poorly known: what is the amount given to kinetic energy, the ion/electron repartition, and the hardness of the particle distributions? We explore these questions with 2D particle-in-cell simulations of ion-electron plasmas. We find that 45 to 75% of the total initial magnetic energy ends up in kinetic energy, this fraction increasing with the inflow magnetization. Depending on the guide field strength, ions get from 30 to 60% of the total kinetic energy. Particles can be separated into two populations that only weakly mix: (i) particles initially in the current sheet, heated by its initial tearing and subsequent contraction of the islands; and (ii) particles from the background plasma that p...
Liu, Y. L.; Kuramitsu, Y.; Moritaka, T.; Chen, S. H.
2017-03-01
Nonthermal acceleration of relativistic electrons due to the wakefield induced by an intense light pulse is investigated. The spectra of the cosmic rays are well represented by power-law. Wakefield acceleration has been considered as a candidate for the origins of cosmic rays. The wakefield can be excited by an intense laser pulse as large-amplitude precursor waves in collisionless shocks in the universe. National Central University (NCU) 100-TW laser facility in Taiwan is able to provide high-repetition rate and short intense laser. To experimentally study the wakefield acceleration for the spectrum of the cosmic rays, particle-in-cell simulations are performed to calculate the energy distribution functions of electrons in fixed laser conditions with various plasma densities. The transitions of wakefields from coherent to inherent are observed as the plasma density increases. The distribution functions indicate that the smooth nonthermal power-law spectra with an index of -2 appear when the incoherent wakefields are excited. In contrast, the mono-peak appear in the spectra when the coherent wakefields are excited. The incoherent wakefields yielding the power-law spectra imply the stochastic accelerating of electrons. To explain the universal nonthermal power-law spectra with an index of -2, we described and extended the stochastic acceleration model based on Fokker-Planck equation by assuming the transition rate as an exponential function.
Transverse phase space mapping of relativistic electron beams using optical transition radiation
G. P. Le Sage
1999-12-01
Full Text Available Optical transition radiation (OTR has proven to be a versatile and effective diagnostic for measuring the profile, divergence, and emittance of relativistic electron beams with a wide range of parameters. Diagnosis of the divergence of modern high brightness beams is especially well suited to OTR interference (OTRI techniques, where multiple dielectric or metal foils are used to generate a spatially coherent interference pattern. Theoretical analysis of measured OTR and OTRI patterns allows precise measurement of electron beam emittance characteristics. Here we describe an extension of this technique to allow mapping of divergence characteristics as a function of transverse coordinates within a measured beam. We present the first experimental analysis of the transverse phase space of an electron beam using all optical techniques. Comparing an optically masked portion of the beam to the entire beam, we measure different angular spread and average direction of the particles. Direct measurement of the phase-space ellipse tilt angle has been demonstrated using this optical masking technique.
Liu Yong; Han Xiang; Ti Ang; Wang Yu-Min; Ling Bi-Li; Hu Li-Qun; Gao Xiang
2012-01-01
This paper presents a theoretical calculation of the effects of relativistic broadening and frequency down-shift on the electron cyclotron emission measurements for a wide range of plasma parameters in the Experimental Advanced Superconducting Tokamak (EAST).The calculation is based on the radiation transfer equation,with the reabsorption and reemission processes taken into account.The broadening effect contributes to the radial resolution of the measurement,and the calculation results indicate that it is ～ 2 cm in the case of the central electron temperature 10 keV.A pseudo radial displacement of the obtained electron temperature profile occurs if the relativistic frequency down-shift effect is not taken into account in the determination of the emission layer position.The shift could be a few centimeters as the electron temperature increases,and this effect should be taken into account.
Stahl, A.; Landreman, M.; Embréus, O.; Fülöp, T.
2017-03-01
Energetic electrons are of interest in many types of plasmas, however previous modeling of their properties has been restricted to the use of linear Fokker-Planck collision operators or non-relativistic formulations. Here, we describe a fully non-linear kinetic-equation solver, capable of handling large electric-field strengths (compared to the Dreicer field) and relativistic temperatures. This tool allows modeling of the momentum-space dynamics of the electrons in cases where strong departures from Maxwellian distributions may arise. As an example, we consider electron runaway in magnetic-confinement fusion plasmas and describe a transition to electron slide-away at field strengths significantly lower than previously predicted.
Stahl, A; Embréus, O; Fülöp, T
2016-01-01
Energetic electrons are of interest in many types of plasmas, however previous modelling of their properties have been restricted to the use of linear Fokker-Planck collision operators or non-relativistic formulations. Here, we describe a fully non-linear kinetic-equation solver, capable of handling large electric-field strengths (compared to the Dreicer field) and relativistic temperatures. This tool allows modelling of the momentum-space dynamics of the electrons in cases where strong departures from Maxwellian distributions may arise. As an example, we consider electron runaway in magnetic-confinement fusion plasmas and describe a transition to electron slide-away at field strengths significantly lower than previously predicted.
Dieckmann, M E; Markoff, S; Borghesi, M; Zepf, M
2015-01-01
The jets of compact accreting objects are composed of electrons and a mixture of positrons and ions. These outflows impinge on the interstellar or intergalactic medium and both plasmas interact via collisionless processes. Filamentation (beam-Weibel) instabilities give rise to the growth of strong electromagnetic fields. These fields thermalize the interpenetrating plasmas. Hitherto, the effects imposed by a spatial non-uniformity on filamentation instabilities have remained unexplored. We examine the interaction between spatially uniform background electrons and a minuscule cloud of electrons and positrons. A square micro-cloud of equally dense electrons and positrons impinges in our particle-in-cell (PIC) simulation on a spatially uniform plasma at rest. The mean speed of the micro-cloud corresponds to a relativistic factor of 15, which is relevant for laboratory experiments and for relativistic astrophysical outflows. The spatial distributions of the leptons and of the electromagnetic fields are examined a...
Single electrons from heavy-flavor mesons in relativistic heavy-ion collisions
Song, Taesoo; Berrehrah, Hamza; Torres-Rincon, Juan M.; Tolos, Laura; Cabrera, Daniel; Cassing, Wolfgang; Bratkovskaya, Elena
2017-07-01
We study the single electron spectra from D - and B - meson semileptonic decays in Au+Au collisions at √{sNN}=200 , 62.4, and 19.2 GeV by employing the parton-hadron-string dynamics (PHSD) transport approach that has been shown to reasonably describe the charm dynamics at Relativistic Heavy Ion Collider and Large Hadron Collider energies on a microscopic level. In this approach the initial charm and bottom quarks are produced by using the PYTHIA event generator which is tuned to reproduce the fixed-order next-to-leading logarithm calculations for charm and bottom production. The produced charm and bottom quarks interact with off-shell (massive) partons in the quark-gluon plasma with scattering cross sections which are calculated in the dynamical quasiparticle model that is matched to reproduce the equation of state of the partonic system above the deconfinement temperature Tc. At energy densities close to the critical energy density (≈0.5 GeV /fm3 ) the charm and bottom quarks are hadronized into D and B mesons through either coalescence or fragmentation. After hadronization the D and B mesons interact with the light hadrons by employing the scattering cross sections from an effective Lagrangian. The final D and B mesons then produce single electrons through semileptonic decay. We find that the PHSD approach well describes the nuclear modification factor RAA and elliptic flow v2 of single electrons in d +Au and Au+Au collisions at √{sNN}=200 GeV and the elliptic flow in Au+Au reactions at √{sNN}=62.4 GeV from the PHENIX Collaboration, however, the large RAA at √{sNN}=62.4 GeV is not described at all. Furthermore, we make predictions for the RAA of D mesons and of single electrons at the lower energy of √{sNN}=19.2 GeV . Additionally, the medium modification of the azimuthal angle ϕ between a heavy quark and a heavy antiquark is studied. We find that the transverse flow enhances the azimuthal angular distributions close to ϕ =0 because the heavy
Maslov, K A; Voskresensky, D N
2016-01-01
Knowledge of the equation of state of the baryon matter plays a decisive role in the description of neutron stars. With an increase of the baryon density the filling of Fermi seas of hyperons and $\\Delta$ isobars becomes possible. Their inclusion into standard relativistic mean-field models results in a strong softening of the equation of state and a lowering of the maximum neutron star mass below the measured values. We extend a relativistic mean-field model with scaled hadron masses and coupling constants developed in our previous works and take into account now not only hyperons but also the $\\Delta$ isobars. We analyze available empirical information to put constraints on coupling constants of $\\Delta$s to mesonic mean fields. We show that the resulting equation of state satisfies majority of presently known experimental constraints.
The extent of non-thermal particle acceleration in relativistic, electron-positron reconnection
Werner, Greg [University of Colorado; Guo, Fan [Los Alamos National Laboratory
2015-07-21
Reconnection is studied as an explanation for high-energy flares from the Crab Nebula. The production of synchrotron emission >100 MeV challenges classical models of acceleration. 3D simulation shows that reconnection, converting magnetic energy to kinetic energy, can accelerate beyond γ_{rad}. The power-law index and high-energy cutoff are important for understanding the radiation spectrum dN/dγ = f(γ) ∝ γ^{-α}. α and cutoff were measured vs. L and σ, where L is system (simulation) size and σ is upstream magnetization (σ = B^{2}/4πnmc^{2}). α can affect the high-energy cutoff. In conclusion, for collisionless relativistic reconnection in electron-positron plasma, without guide field, n_{b}/n_{d}=0.1: (1) relativistic magnetic reconnection yields power-law particle spectra, (2) the power law index decreases as σ increases, approaching ≈1.2. (3) the power law is cut off at an energy related to acceleration within a single current layer, which is proportional to the current layer length (for small systems, that length is the system length, yielding γ_{c2} ≈ 0.1 L/ρ_{0}; for large systems, the layer length is limited by secondary tearing instability, yielding γ_{c1} ≈ 4σ; the transition from small to large is around L/ρ_{0} = 40σ.). (4) although the large-system energy cutoff is proportional to the average energy per particle, it is significantly higher than the average energy per particle.
M. E. Dieckmann
2008-11-01
Full Text Available Recent particle-in-cell (PIC simulation studies have addressed particle acceleration and magnetic field generation in relativistic astrophysical flows by plasma phase space structures. We discuss the astrophysical environments such as the jets of compact objects, and we give an overview of the global PIC simulations of shocks. These reveal several types of phase space structures, which are relevant for the energy dissipation. These structures are typically coupled in shocks, but we choose to consider them here in an isolated form. Three structures are reviewed. (1 Simulations of interpenetrating or colliding plasma clouds can trigger filamentation instabilities, while simulations of thermally anisotropic plasmas observe the Weibel instability. Both transform a spatially uniform plasma into current filaments. These filament structures cause the growth of the magnetic fields. (2 The development of a modified two-stream instability is discussed. It saturates first by the formation of electron phase space holes. The relativistic electron clouds modulate the ion beam and a secondary, spatially localized electrostatic instability grows, which saturates by forming a relativistic ion phase space hole. It accelerates electrons to ultra-relativistic speeds. (3 A simulation is also revised, in which two clouds of an electron-ion plasma collide at the speed 0.9c. The inequal densities of both clouds and a magnetic field that is oblique to the collision velocity vector result in waves with a mixed electrostatic and electromagnetic polarity. The waves give rise to growing corkscrew distributions in the electrons and ions that establish an equipartition between the electron, the ion and the magnetic energy. The filament-, phase space hole- and corkscrew structures are discussed with respect to electron acceleration and magnetic field generation.
Roy, Soumendra K.; Jian, Tian; Lopez, Gary V.; Li, Wei-Li; Su, Jing; Bross, David H.; Peterson, Kirk A.; Wang, Lai-Sheng; Li, Jun
2016-02-01
The observation of the gaseous UFO- anion is reported, which is investigated using photoelectron spectroscopy and relativisitic ab initio calculations. Two strong photoelectron bands are observed at low binding energies due to electron detachment from the U-7sσ orbital. Numerous weak detachment bands are also observed due to the strongly correlated U-5f electrons. The electron affinity of UFO is measured to be 1.27(3) eV. High-level relativistic quantum chemical calculations have been carried out on the ground state and many low-lying excited states of UFO to help interpret the photoelectron spectra and understand the electronic structure of UFO. The ground state of UFO- is linear with an O-U-F structure and a 3H4 spectral term derived from a U 7sσ25fφ15fδ1 electron configuration, whereas the ground state of neutral UFO has a 4H7/2 spectral term with a U 7sσ15fφ15fδ1 electron configuration. Strong electron correlation effects are found in both the anionic and neutral electronic configurations. In the UFO neutral, a high density of electronic states with strong configuration mixing is observed in most of the scalar relativistic and spin-orbit coupled states. The strong electron correlation, state mixing, and spin-orbit coupling of the electronic states make the excited states of UFO very challenging for accurate quantum chemical calculations.
Xiang-Jun Kuang; Xin-Qiang Wang; Gao-Bin Liu
2013-03-01
A comparative study between all-electron relativistic (AER) calculation and all-electron (AE) calculation on the H2 molecule adsorption onto small gold clusters has been performed. Compared with the corresponding AuH2 cluster obtained by AE method, the AuH2 cluster obtained by AER method has much shorter Au-H bond-length, much longer H-H distance, larger binding energy and adsorption energy, higher vertical ionization potentials (VIP), greater charge transfer, higher vibrational frequency of Au-H mode and lower vibrational frequency of H-H mode. The delocalization of the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) for AuH2 cluster obtained by AER method is obvious. All these characteristics suggest that the scalar relativistic effect might strengthen the Au-H bond and weaken the H-H bond. It is believed that the scalar relativistic effect is favourable to the H2 molecule adsorption onto small gold cluster and the reactivity enhancement of H2 molecule. It may be one of the reasons why the dissociative adsorptions take place in some AuH2 clusters. With increasing size of AuH2 clusters, the influence of scalar relativistic effect becomes more significant. Some further studies focused on the influence of scalar relativistic effect on the adsorption behaviour of other small molecules onto gold clusters are necessary in the future.
Investigating the Relationship of EMIC Waves and Relativistic Electron Precipitation Events
Woodger, L. A.; Millan, R. M.; Goldstein, J.; McCarthy, M. P.; Smith, D. M.; Sample, J. G.
2007-05-01
EMIC waves are generated and driven by anisotropic ring current protons. These unstable protons are injected into the inner magnetosphere by increased earthward convection during periods of elevated geomagnetic activity. A study by Meredith et al. (2003) showed EMIC wave events resonant with radiation belt electrons of energies less then 2MeV were located near the plasmapause in high density regions typical of the plasmaspheric plume. This study seeks to investigate the theory of relativistic electron precipitation (REP) due to wave particle interaction with EMIC waves. REP events were detected by balloon borne instrumentation during the MAXIS and MINIS balloon campaigns conducted in Jan. of 2000 and 2005 respectively. The location of these events with respect to the plasmapause will be explored using a plasmapause test particle simulation code and IMAGE EUV data. Also, data provided by the LANL satellite MPA instrument will be used to investigate the temperature anisotropy of ring current protons that may drive EMIC waves in the region of detected REP.
Improved Segmented All-Electron Relativistically Contracted Basis Sets for the Lanthanides.
Aravena, Daniel; Neese, Frank; Pantazis, Dimitrios A
2016-03-08
Improved versions of the segmented all-electron relativistically contracted (SARC) basis sets for the lanthanides are presented. The second-generation SARC2 basis sets maintain efficient construction of their predecessors and their individual adaptation to the DKH2 and ZORA Hamiltonians, but feature exponents optimized with a completely new orbital shape fitting procedure and a slightly expanded f space that results in sizable improvement in CASSCF energies and in significantly more accurate prediction of spin-orbit coupling parameters. Additionally, an extended set of polarization/correlation functions is constructed that is appropriate for multireference correlated calculations and new auxiliary basis sets for use in resolution-of-identity (density-fitting) approximations in combination with both DFT and wave function based treatments. Thus, the SARC2 basis sets extend the applicability of the first-generation DFT-oriented basis sets to routine all-electron wave function-based treatments of lanthanide complexes. The new basis sets are benchmarked with respect to excitation energies, radial distribution functions, optimized geometries, orbital eigenvalues, ionization potentials, and spin-orbit coupling parameters of lanthanide systems and are shown to be suitable for the description of magnetic and spectroscopic properties using both DFT and multireference wave function-based methods.
Sun, Lingpeng; Klecker, Berndt; Krucker, Saem; Droege, Wolfgang
2010-01-01
We report for several solar energetic particle events intensity and anisotropy measurements of energetic electrons in the energy range ~ 27 to ~ 500 keV as observed with the Wind and ACE spacecraft in June 2000. The observations onboard Wind show bimodal pitch angle distributions (PAD), whereas ACE shows PADs with one peak, as usually observed for impulsive injection of electrons at the Sun. During the time of observation Wind was located upstream of the Earth's bow shock, in the dawn - noon sector, at distances of ~ 40 to ~ 70 Earth radii away from the Earth, and magnetically well connected to the quasi-parallel bow shock, whereas ACE, located at the libration point L1, was not connected to the bow shock. The electron intensity-time profiles and energy spectra show that the backstreaming electrons observed at Wind are not of magnetospheric origin. The observations rather suggest that the bi-modal electron PADs are due to reflection or scattering at an obstacle located at a distance of less than ~ 150 Earth r...
Kourakis, I.; McKerr, M.; Elkamash, I. S.; Haas, F.
2017-10-01
The dispersion properties of electrostatic waves propagating in ultrahigh density plasma are investigated, from first principles, in a one-dimensional geometry. A self-consistent multispecies plasma fluid model is taken as starting point, incorporating electron degeneracy and relativistic effects. The inertia of all plasma components is retained, for rigor. Exact expressions are obtained for the oscillation frequency, and the phase and group velocity of electrostatic waves is computed. Two branches are obtained, viz. an acoustic low-frequency dispersion branch and an upper (optic-like) branch: these may be interpreted as ion-acoustic and electron plasma (Langmuir) waves, respectively, as in classical plasmas, yet bearing an explicit correction in account of relativistic and electron degeneracy effects. The electron plasma frequency is shown to reduce significantly at high values of the density, due to the relativistic effect. The result is compared with approximate models, wherein either electrons are considered inertialess (low-frequency ionic scale) or ions are considered to be stationary (Langmuir-wave limit).
Shprits, Yuri Y.; Elkington, Scot R.; Meredith, Nigel P.; Subbotin, Dmitriy A.
2008-11-01
In this paper, we focus on the modeling of radial transport in the Earth's outer radiation belt. A historical overview of the first observations of the radiation belts is presented, followed by a brief description of radial diffusion. We describe how resonant interactions with poloidal and toroidal components of the ULF waves can change the electron's energy and provide radial displacements. We also present radial diffusion and guiding center simulations that show the importance of radial transport in redistributing relativistic electron fluxes and also in accelerating and decelerating radiation belt electrons. We conclude by presenting guiding center simulations of the coupled particle tracing and magnetohydrodynamic (MHD) codes and by discussing the origin of relativistic electrons at geosynchronous orbit. Local acceleration and losses and 3D simulations of the dynamics of the radiation belt fluxes are discussed in the companion paper [Shprits, Y.Y., Subbotin, D.A., Meredith, N.P., Elkington, S.R., 2008. Review of modeling of losses and sources of relativistic electrons in the outer radiation belt II: Local acceleration and loss. Journal of Atmospheric and Solar-Terrestrial Physics, this issue. doi:10.1016/j.jastp.2008.06.014].
Observation of relativistic electron precipitation during a rapid decrease of trapped electron flux
Millan, R. M.; Lin, R. P.; Smith, D. M.; McCarthy, M. P.; Sample, J. G.; Shprits, Y.
2006-12-01
Rapid depletions of the trapped electron flux are often observed, and illustrate the important role played by losses in controlling electron variability in the radiation belts. The observed decrease may be partly due to adiabatic effects, but some of the electrons are lost either through magnetopause shadowing or through precipitation into Earth's atmosphere. On January 19, 2000, duskside precipitation was observed near the start of a rapid flux depletion event, during a period of magnetic field stretching in the tail. The observations were made with the germanium spectrometer on the MAXIS balloon payload and show that real losses were occurring during the initial decrease which has previously been attributed to purely adiabatic effects. A quantitative comparison of the precipitation rate with the change in electron flux measured at GPS implies that only ~1% of the loss cone was filled, however, precipitation alone is sufficient to account for the flux decrease if it extended over 2-3 hours of local time. We present these results and compare the observed loss rate with the theoretical loss rate expected for pitch-angle scattering by EMIC waves.
A monolithic relativistic electron beam source based on a dielectric laser accelerator structure
McNeur, Josh; Carranza, Nestor; Travish, Gil; Yin Hairong; Yoder, Rodney [UCLA Dept. of Physics and Astronomy, Los Angeles, CA 90095 (United States); College of Physical Electronics, University of Electronic Science and Technology of China, Chengdu, Sichuan, 610054 (China); Manhattanville College, Physics Dept., 2900 Purchase St., Purchase, NY 10577 (United States)
2012-12-21
Work towards a monolithic device capable of producing relativistic particle beams within a cubic-centimeter is detailed. We will discuss the Micro-Accelerator Platform (MAP), an optical laser powered dielectric accelerator as the main building block of this chip-scale source along with a field enhanced emitter and a region for sub-relativistic acceleration.
Mass Customization in the Electronics Industry
Hvam, Lars
2006-01-01
This article describes how Amercian Power Conversion (APC), a company in the electronics industry, has used the principles of mass customization to achieve major improvements of its efficiency and performance. APC sells, designs, produces, delivers, and installs large complex infrastructure systems...
Gamayunov, K. V.; Khazanov, G. V.
2007-01-01
We consider the effect of oblique EMIC waves on relativistic electron scattering in the outer radiation belt using simultaneous observations of plasma and wave parameters from CRRES. The main findings can be s ummarized as follows: 1. In 1comparison with field-aligned waves, int ermediate and highly oblique distributions decrease the range of pitc h-angles subject to diffusion, and reduce the local scattering rate b y an order of magnitude at pitch-angles where the principle absolute value of n = 1 resonances operate. Oblique waves allow the absolute va lue of n > 1 resonances to operate, extending the range of local pitc h-angle diffusion down to the loss cone, and increasing the diffusion at lower pitch angles by orders of magnitude; 2. The local diffusion coefficients derived from CRRES data are qualitatively similar to the local results obtained for prescribed plasma/wave parameters. Conseq uently, it is likely that the bounce-averaged diffusion coefficients, if estimated from concurrent data, will exhibit the dependencies similar to those we found for model calculations; 3. In comparison with f ield-aligned waves, intermediate and highly oblique waves decrease th e bounce-averaged scattering rate near the edge of the equatorial lo ss cone by orders of magnitude if the electron energy does not excee d a threshold (approximately equal to 2 - 5 MeV) depending on specified plasma and/or wave parameters; 4. For greater electron energies_ ob lique waves operating the absolute value of n > 1 resonances are more effective and provide the same bounce_averaged diffusion rate near the loss cone as fiel_aligned waves do.
M. Fukata
Full Text Available During the recovery phase of geomagnetic storms, the flux of relativistic (>2 MeV electrons at geosynchronous orbits is enhanced. This enhancement reaches a level that can cause devastating damage to instruments on satellites. To predict these temporal variations, we have developed neural network models that predict the flux for the period 1–12 h ahead. The electron-flux data obtained during storms, from the Space Environment Monitor on board a Geostationary Meteorological Satellite, were used to construct the model. Various combinations of the input parameters AL, SAL, Dst and SDst were tested (where S denotes the summation from the time of the minimum Dst. It was found that the model, including SAL as one of the input parameters, can provide some measure of relativistic electron-flux prediction at geosynchronous orbit during the recovery phase. We suggest from this result that the relativistic electron-flux enhancement during the recovery phase is associated with recurring substorms after Dst minimum and their accumulation effect.
Key words. Magnetospheric physics (energetic particles, trapped; magnetospheric configuration and dynamics; storms and substorms
Relativistic electrons and magnetic fields of the M87 jet on the ∼10 Schwarzschild radii scale
Kino, M. [Korea Astronomy and Space Science Institute, 776 Daedukdae-ro, Yusong, Daejon 305-348 (Korea, Republic of); Takahara, F. [Department of Earth and Space Science, Osaka University, Toyonaka 560-0043 (Japan); Hada, K. [INAF—Istituto di Radioastronomia, via Gobetti 101, I-40129 Bologna (Italy); Doi, A. [Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, 229-8510 Sagamihara (Japan)
2014-05-01
We explore energy densities of the magnetic fields and relativistic electrons in the M87 jet. Since the radio core at the jet base is identical to the optically thick surface against synchrotron self-absorption (SSA), the observing frequency is identical to the SSA turnover frequency. As a first step, we assume the radio core has a simple uniform sphere geometry. Using the observed angular size of the radio core measured by the Very Long Baseline Array at 43 GHz, we estimate the energy densities of magnetic fields (U{sub B} ) and relativistic electrons (U{sub e} ) on the basis of the standard SSA formula. Imposing the condition that the Poynting power and kinetic power of relativistic electrons should be smaller than the total power of the jet, we find that (1) the allowed range of the magnetic field strength (B {sub tot}) is 1 G ≤ B {sub tot} ≤ 15 G and that (2) 1 × 10{sup –5} ≤ U{sub e} /U{sub B} ≤ 6 × 10{sup 2} holds. The uncertainty of U{sub e} /U{sub B} comes from the strong dependence on the angular size of the radio core and the minimum Lorentz factor of non-thermal electrons (γ {sub e,min}) in the core. It is still unsettled whether resultant energetics are consistent with either the magnetohydrodynamic jet or the kinetic power dominated jet even on the ∼10 Schwarzschild radii scale.
Borovskiy, A. V. [Department of Computer Science and Cybernetics, Baikal State University of Economics and Law, 11 Lenin Street, Irkutsk 664003 (Russian Federation); Galkin, A. L. [Coherent and Nonlinear Optics Department, A.M. Prokhorov General Physics Institute of the RAS, 38 Vavilov Street, Moscow 119991 (Russian Federation); Department of Physics of MBF, Pirogov Russian National Research Medical University, 1 Ostrovitianov Street, Moscow 117997 (Russian Federation); Kalashnikov, M. P., E-mail: galkin@kapella.gpi.ru [Max-Born-Institute for Nonlinear Optics and Short-Time Spectroscopy, 2a Max-Born-Strasse, Berlin 12489 (Germany)
2015-04-15
The new method of calculating energy spectra of accelerated electrons, based on the parameterization by their initial coordinates, is proposed. The energy spectra of electrons accelerated by Gaussian ultra-short relativistic laser pulse at a selected angle to the axis of the optical system focusing the laser pulse in a low density gas are theoretically calculated. The two-peak structure of the electron energy spectrum is obtained. Discussed are the reasons for its appearance as well as an applicability of other models of the laser field.
Zhidkov, A.; Masuda, S.; Bulanov, S. S.; Koga, J.; Hosokai, T.; Kodama, R.
2014-05-01
Nonlinear cascade scattering of intense, tightly focused laser pulses by relativistic electrons is studied numerically in the classical approximation including radiation damping for the quantum parameter ⟨ℏωxray⟩/ɛ <1 and an arbitrary radiation parameter χ. The electron's energy loss, along with its being scattered to the side by the ponderomotive force, makes scattering in the vicinity of a high laser field nearly impossible at high electron energies. The use of a second, copropagating laser pulse as a booster is shown to partially solve this problem.
Badarin, A. A.; Kurkin, S. A. [Saratov State University (Russian Federation); Koronovskii, A. A. [Yuri Gagarin State Technical University (Russian Federation); Rak, A. O. [Belorussian State University of Informatics and Radioelectronics (Belarus); Hramov, A. E., E-mail: hramovae@gmail.com [Saratov State University (Russian Federation)
2017-03-15
The development and interaction of Bursian and diocotron instabilities in an annular relativistic electron beam propagating in a cylindrical drift chamber are investigated analytically and numerically as functions of the beam wall thickness and the magnitude of the external uniform magnetic field. It is found that the interaction of instabilities results in the formation of a virtual cathode with a complicated rotating helical structure and several reflection regions (electron bunches) in the azimuthal direction. It is shown that the number of electron bunches in the azimuthal direction increases with decreasing beam wall thickness and depends in a complicated manner on the magnitude of the external magnetic field.
Teraki, Yuto
2014-01-01
We examine the radiation spectra from relativistic electrons moving in a Langmuir turbulence expected to exist in high energy astrophysical objects by using numerical method. The spectral shape is characterized by the spatial scale {\\lambda}, field strength {\\sigma}, and frequency of the Langmuir waves, and in term of frequency they are represented by {\\omega}_0 = 2{\\pi}c/{\\lambda}, {\\omega}_st = e{\\sigma}/mc, and {\\omega}_p, respectively. We normalize {\\omega}_st and {\\omega}_p by {\\omega}_0 as \\a \\equiv {\\omega}_st/{\\omega}_0 and \\b \\equiv{\\omega}_p/{\\omega}_0, and examine the spectral shape in the a-b plane. An earlier study based on Diffusive Radiation in Langmuir turbulence (DRL) theory by Fleishman and Toptygin showed that the typical frequency is {\\gamma}^2{\\omega}_p and that the low frequency spectrum behaves as F_{\\omega} pronto {\\omega}^1 for b > 1 irrespective of a. Here, we adopt the first principle numerical approach to obtain the radiation spectra in more detail. We generate Langmuir turbulence ...
Potylitsyn, Alexander; Karataev, Pavel
2012-05-01
This volume contains papers presented at the IX International Symposium on Radiation from Relativistic Electrons in Periodic Structures (RREPS'11) which was held at Royal Holloway, University of London on September 12-16, Egham, United Kingdom. The symposium was organized jointly by Royal Holloway, University of London and Tomsk Polytechnic University, Tomsk, Russia. RREPS is a biennial series of symposia founded in September 1993 as an initiative of the Nuclear Physics Institute at Tomsk Polytechnic University. The intention was to strengthen the basic and applied research focused on radiation from relativistic electrons in condensed media, particularly from natural and artificial periodic structures, and to review the research activity in this area. Since then, the symposium has developed into a forum attracting young scientists from different areas of research and from many countries. Previous successful symposia were held at Tomsk, Russia (1993, 1995, 1997, 2003), Lake Baikal, Russia (1999), Lake Aiya, Altai, Russia (2001), Czech Technical University in Prague, Czech Republic (2007) and Zvenigorod, Moscow region, Russia (2009). As an outcome of the symposia the conference proceedings have been published in Nuclear Instruments and Methods in Physics Research, Section B (Vol. 145 No 1-2, October 1998; Vol. 173 No 1-2, January 2001; Vol. 201 No 1 January 2003; Vol. 227 No 1-2, January 2005; Vol. 266 No 17, September 2008) and Journal of Physics: Conference Series (Vol. 236, June 2010). The purpose of the present RREPS'11 symposium was to review the up-to-date situation in the area of electromagnetic radiation generated by relativistic charged particles in condensed media, and to discuss the research strategy for the near future. Nowadays, electromagnetic radiation studies cover electron energies from a few MeV up to hundreds of GeV in many laboratories throughout the world. The goal is to study the physics of the generation of various kinds of radiation and their
Agostino Marinelli
2010-11-01
Full Text Available Longitudinal space-charge forces from density fluctuations generated by shot noise can be a major source of microbunching instability in relativistic high brightness electron beams. The gain in microbunching due to this effect is broadband, extending at least up to optical frequencies, where the induced structure on the beam distribution gives rise to effects such as coherent optical transition radiation. In the high-frequency regime, theoretical and computational analyses of microbunching formation require a full three-dimensional treatment. In this paper we address the problem of space-charge induced optical microbunching formation in the high-frequency limit when transverse thermal motion due to finite emittance is included for the first time. We derive an analytical description of this process based on the beam’s plasma dielectric function. We discuss the effect of transverse temperature on the angular distribution of microbunching gain and its connection to the physics of Landau damping in longitudinal plasma oscillations. Application of the theory to a relevant experimental scenario is discussed. The analytical results obtained are then compared to the predictions arising from high resolution three-dimensional molecular dynamics simulations.
Wakefield-acceleration of relativistic electrons with few-cycle laser pulses at kHz-repetition-rate
Guenot, Diego; Gustas, Dominykas; Vernier, Aline; Boehle, Frederik; Beaurepaire, Benoit; Lopez-Martens, Rodrigo; Faure, Jerome; Appli Team
2016-10-01
The generation of relativistic electron beams using laser wakefield acceleration has become a standard technique, providing low emittance electron bunches with femtosecond durations. However, this technique usually requires multi-ten-terawatt lasers and is thus limited to low repetition-rate (typically 10 Hz or less). We have recently demonstrated the generation of few MeV electrons using 2.5-mJ, 4-fs, 1-kHz repetition-rate laser pulses, focused to relativistic intensity onto a gas jet with electron density 1020 cm-3. We have investigated the influence of the pulse duration, the gas density. We demonstrated that an electron beam with a charge in the range of 10-fC/shot, with a divergence of 20-mrad and a peaked spectrum with energies between 2 and 4 MeV can be generated at kHz repetition-rate. These results confirm the possibility of using few-cycle laser pulses with very low energy for exciting wakefields in the bubble regime and for trapping electrons, as predicted by PIC simulations. This kHz electron source is ideally suited for performing electron diffraction experiments with very high temporal resolution. Our results also open the way to other applications, such as the generation of a kHz ultrafast X-ray source. ERC femtoelec.
Kuzichev, Ilya; Shklyar, David
2016-04-01
One of the most challenging problems of the radiation belt studies is the problem of particles energization. Being related to the process of particle precipitation and posing a threat to scientific instruments on satellites, the problem of highly energetic particles in the radiation belts turns out to be very important. A lot of progress has been made in this field, but still some aspects of the energization process remain open. The main mechanism of particle energization in the radiation belts is the resonant interaction with different waves, mainly, in whistler frequency range. The problem of special interest is the resonant wave-particle interaction of the electrons of relativistic energies. Relativistic resonance condition provides some important features such as the so-called relativistic turning acceleration discovered by Omura et al. [1, 2]. This process appears to be a very efficient mechanism of acceleration in the case of interaction with the whistler-mode waves propagating along geomagnetic field lines. But some whistler-mode waves propagate obliquely to the magnetic field lines, and the efficiency of relativistic turning acceleration in this case is to be studied. In this report, we present the Hamiltonian theory of the resonant interaction of relativistic electrons with oblique monochromatic whistler-mode waves. We have shown that the presence of turning point requires a special treatment when one aims to derive the resonant Hamiltonian, and we have obtained two different resonant Hamiltonians: one to be applied far enough from the turning point, while another is valid in the vicinity of the turning point. We have performed numerical simulation of relativistic electron interaction with whistler-mode waves generated in the ionosphere by a monochromatic source. It could be, for example, a low-frequency transmitter. The wave-field distribution along unperturbed particle trajectory is calculated by means of geometrical optics. We show that the obliquity of
Murphy, G. C.; Dieckmann, M. E.; Bret, A.; Drury, L. O'c.
2010-12-01
Context. The prompt emissions of gamma-ray bursts (GRBs) are seeded by radiating ultrarelativistic electrons. Kinetic energy dominated internal shocks propagating through a jet launched by a stellar implosion, are expected to dually amplify the magnetic field and accelerate electrons. Aims: We explore the effects of density asymmetry and of a quasi-parallel magnetic field on the collision of two plasma clouds. Methods: A two-dimensional relativistic particle-in-cell (PIC) simulation models the collision with 0.9c of two plasma clouds, in the presence of a quasi-parallel magnetic field. The cloud density ratio is 10. The densities of ions and electrons and the temperature of 131 keV are equal in each cloud, and the mass ratio is 250. The peak Lorentz factor of the electrons is determined, along with the orientation and the strength of the magnetic field at the cloud collision boundary. Results: The magnetic field component orthogonal to the initial plasma flow direction is amplified to values that exceed those expected from the shock compression by over an order of magnitude. The forming shock is quasi-perpendicular due to this amplification, caused by a current sheet which develops in response to the differing deflection of the upstream electrons and ions incident on the magnetised shock transition layer. The electron deflection implies a charge separation of the upstream electrons and ions; the resulting electric field drags the electrons through the magnetic field, whereupon they acquire a relativistic mass comparable to that of the ions. We demonstrate how a magnetic field structure resembling the cross section of a flux tube grows self-consistently in the current sheet of the shock transition layer. Plasma filamentation develops behind the shock front, as well as signatures of orthogonal magnetic field striping, indicative of the filamentation instability. These magnetic fields convect away from the shock boundary and their energy density exceeds by far the
Ross, James Steven [Univ. of California, San Diego, CA (United States)
2010-01-01
Simultaneous scattering from electron-plasma waves and ion-acoustic waves is used to measure local laser-produced plasma parameters with high spatiotemporal resolution including electron temperature and density, average charge state, plasma flow velocity, and ion temperature. In addition, the first measurements of relativistic modifications in the collective Thomson scattering spectrum from thermal electron-plasma fluctuations are presented [1]. Due to the high phase velocity of electron-plasma fluctuations, relativistic effects are important even at low electron temperatures (T_{e} < 1 keV). These effects have been observed experimentally and agree well with a relativistic treatment of the Thomson scattering form factor [2]. The results are important for the interpretation of scattering measurements from laser produced plasmas. Thomson scattering measurements are used to characterize the hydrodynamics of a gas jet plasma which is the foundation for a broad series of laser-plasma interaction studies [3, 4, 5, 6]. The temporal evolution of the electron temperature, density and ion temperature are measured. The measured electron density evolution shows excellent agreement with a simple adiabatic expansion model. The effects of high temperatures on coupling to hohlraum targets is discussed [7]. A peak electron temperature of 12 keV at a density of 4.7 × 10^{20}cm^{-3} are measured 200 μm outside the laser entrance hole using a two-color Thomson scattering method we developed in gas jet plasmas [8]. These measurements are used to assess laser-plasma interactions that reduce laser hohlraum coupling and can significantly reduce the hohlraum radiation temperature.
Rajat K. Chaudhuri
2003-12-01
Full Text Available Abstract: The coupled cluster based linear response theory which is applicable to the direct calculation of atomic and molecular properties are presented and applied to compute the ionization potentials and excitation energies of light and moderately heavy atoms. The eÃ‚Â®ect of electron correlation on the ground and excited states is studied using Hartree-Fock, Dirac-Fock and approximate two-component relativistic spinors.
K M Aggarwal; F P Keenan
2006-09-01
In a recent paper [Pramana - J. Phys. 64, 129 (2005)] results have been presented for electron impact excitation collision strengths for transitions among the fine-structure levels of the 2s22p6 and 2s22p53s configurations of Ni XIX. In this paper we demonstrate through an independent calculation with the relativistic -matrix code that those results are unreliable and the conclusions drawn are invalid.
Sarlanis, Christos; Heber, Bernd; Labrenz, Johannes; Kühl, Patrick; Marquardt, Johannes; Dimitroulakos, John; Papaioannou, Athanasios; Posner, Arik
2017-04-01
Solar Energetic Particle (SEP) events are one of the most important elements of space weather. Given that the complexity of the underlying physical processes of the acceleration and propagation of SEP events is still a very active research area, the prognosis of SEP event occurrence and their corresponding characteristics remains challenging. In order to provide up to an hour warning time before these particles arrive at Earth, relativistic electron and below 50 MeV proton data from the Electron Proton Helium Instrument (EPHIN) on SOHO were used to implement the 'Relativistic Electron Alert System for Exploration (REleASE)'. The REleASE forecasting scheme was recently rewritten in the open access programming language PYTHON and will be made publicly available. As a next step, along with relativistic electrons (v > 0.9 c) provided by SOHO, near-relativistic (v innovation programme under grant agreement No 637324.
Observation of Shot Noise Suppression at Optical Wavelengths in a Relativistic Electron Beam
Ratner, Daniel; Stupakov, Gennady; /SLAC
2012-06-19
Control of collective properties of relativistic particles is increasingly important in modern accelerators. In particular, shot noise affects accelerator performance by driving instabilities or by competing with coherent processes. We present experimental observations of shot noise suppression in a relativistic beam at the Linac Coherent Light Source. By adjusting the dispersive strength of a chicane, we observe a decrease in the optical transition radiation emitted from a downstream foil. We show agreement between the experimental results, theoretical models, and 3D particle simulations.
Chaudhuri, Supriya K.; Mukherjee, Prasanta K.; Fricke, Burkhard
2017-03-01
The effect of Debye and quantum plasma environment on the structural properties such as spin orbit splitting, relativistic mass correction and Darwin term for a few iso-electronic members of hydrogen viz. C5 +, O7 +, Ne9 +, Mg11 +, Si13 +, S15 +, Ar17 +, Ca19 + and Ti21 + has been analysed systematically for the first time for a range of coupling strengths of the plasma. The Debye plasma environment has been treated under a standard screened Coulomb potential (SCP) while the quantum plasma has been treated under an exponential cosine screened Coulomb potential (ECSCP). Estimation of the spin orbit splitting under SCP and ECSCP plasma is restricted to the lowest two dipole allowed states while for the other two properties, the ground state as well as the first two excited states have been chosen. Calculations have been extended to nuclear charges for which appreciable relativistic corrections are noted. In all cases calculations have been extended up to such screening parameters for which the respective excitation energies tend towards their stability limit determined by the ionisation potential at that screening parameter. Interesting behavior of the respective properties with respect to the plasma coupling strength has been noted.
Martinolli, E
2003-04-15
This work is dedicated to the study of the energy deposition of fast electrons in matter. This topic is of prime importance for inertial fusion driven by laser since relativistic electrons are produced in laser-matter interaction for a laser operating in ultra-intense regime. This thesis is made up of: a theoretical chapter dealing with the generation and transport of fast electrons, of 2 chapters reporting experimental data obtained with optical and X-rays diagnostics at the laser facilities of LULI in France and RAL in U.K., and of a chapter dedicated to the simulation of electron transport by using a Monte-Carlo code combined to a hybrid collisional-electromagnetic PIC code. A new spectrometer has been designed: the detection of K{alpha} rays coming from a fluorescent layer embedded in the target has allowed us to assess the size of the electron beam and the level of ionisation. (A.C.)
Lee, Y.S.
1977-11-01
The effects of the 4f shell of electrons and the relativity of valence electrons are compared. The effect of 4f shell (lanthanide contraction) is estimated from the numerical Hartree-Fock (HF) calculations of pseudo-atoms corresponding to Hf, Re, Au, Hg, Tl, Pb and Bi without 4f electrons and with atomic numbers reduced by 14. The relativistic effect estimated from the numerical Dirac-Hartree-Fock (DHF) calculations of those atoms is comparable in the magnitude with that of the 4f shell of electrons. Both are larger for 6s than for 5d or 6p electrons. The various relativistic effects on valence electrons are discussed in detail to determine the proper level of the approximation for the valence electron calculations of systems with heavy elements. An effective core potential system has been developed for heavy atoms in which relativistic effects are included in the effective potentials.
Relativistic Guiding Center Equations
White, R. B. [PPPL; Gobbin, M. [Euratom-ENEA Association
2014-10-01
In toroidal fusion devices it is relatively easy that electrons achieve relativistic velocities, so to simulate runaway electrons and other high energy phenomena a nonrelativistic guiding center formalism is not sufficient. Relativistic guiding center equations including flute mode time dependent field perturbations are derived. The same variables as used in a previous nonrelativistic guiding center code are adopted, so that a straightforward modifications of those equations can produce a relativistic version.
Riazantseva, Maria; Antonova, Elizaveta; Marjin, Boris; Barinova, Vera; Myagkova, Irina
We analyze the simultaneous observations of the fluxes of auroral electrons and the fluxes of relativistic electrons at the external boundary of the outer electron radiation belts using data of METEOR-M No1 satellite for the period from November 3, 2009 till April 30, 2010. The geomagnetic conditions during analyzed period were comparatively quite. METEOR-M No.1 has a polar solar-synchronous circular orbit with an altitude of ~832 km, a period of 101.3 min, and an inclination of 98.068 degrees. The electrons with the energies from 0.1 to 13 MeV and protons from 1 to 260 MeV were measured by GGAK-M instrument composed by semiconductor and scintillator detectors. The plasma electrons with the energies from 0.03 to 16 keV were measured by the segment electrostatic analyzer. The observation of fluxes of relativistic electrons were selected inside the auroral oval connected with the development of magnetospheric substorms. However, the fluxes of relativistic electrons are also observed during absolutely quite time intervals. We compare the obtained results with the observations of CORONAS-FOTON satellite demonstrating the quasistationary (for more than 3 hours) increases of relativistic electrons at the latitudes of the auroral oval and argue that the processes inside the auroral oval can play the considerable role in the acceleration of relativistic electrons.
Development of a 300-kV Marx generator and its application to drive a relativistic electron beam
Y Choyal; Lalit Gupta; Preeti Vyas; Prasad Deshpande; Anamika Chaturvedi; K C Mittal; K P Maheshwari
2005-12-01
We have indigenously developed a twenty-stage vertical structure type Marx generator. At a matched load of $90-100 \\Omega$, for 25 kV DC charging, an output voltage pulse of 230 kV, and duration 150 ns is obtained. This voltage pulse is applied to a relativistic electron beam (REB) planar diode. For a cathode-anode gap of 7·5 mm, an REB having beam voltage 160 kV and duration 150 ns is obtained. Brass as well as aluminum explosive electron emission-type cathodes have been used.
Dynamics of a relativistic electron beam in a high-current diode with a knife-edge cathode
Babykin, V. M.; Gordeev, A. V.; Golovin, G. T.; Korolev, V. D.; Kopchikov, A. V.; Tulupov, M. V.; Chernenko, A. S.; Shuvaev, V. Iu.
1991-09-01
The generation of a 130-kA electron beam with a pulse width of 60 ns is investigated experimentally and analytically. In particular, attention is given to the volt-ampere characteristics of knife-edge cathodes of different geometries, angular scatter dynamics, and beam structure. A study of the relativistic electron beam dynamics shows that diode operation in these experiments can be approximated by a formula allowing for the finite thickness of the knife-edge cathode and for plasma and ion motion in the diode gap.
Plettner, T.; Byer, R.L.; /Stanford U., Phys. Dept.; Colby, E.; Cowan, B.; Sears, C.M.S.; Spencer, J.E.; Siemann, R.H.; /SLAC
2006-03-01
We recently achieved the first experimental observation of laser-driven particle acceleration of relativistic electrons from a single Gaussian near-infrared laser beam in a semi-infinite vacuum. This article presents an in-depth account of key aspects of the experiment. An analysis of the transverse and longitudinal forces acting on the electron beam is included. A comparison of the observed data to the acceleration viewed as an inverse transition radiation process is presented. This is followed by a detailed description of the components of the experiment and a discussion of future measurements.
Roy, Soumendra K; Jian, Tian; Lopez, Gary V; Li, Wei-Li; Su, Jing; Bross, David H; Peterson, Kirk A; Wang, Lai-Sheng; Li, Jun
2016-02-28
The observation of the gaseous UFO(-) anion is reported, which is investigated using photoelectron spectroscopy and relativisitic ab initio calculations. Two strong photoelectron bands are observed at low binding energies due to electron detachment from the U-7sσ orbital. Numerous weak detachment bands are also observed due to the strongly correlated U-5f electrons. The electron affinity of UFO is measured to be 1.27(3) eV. High-level relativistic quantum chemical calculations have been carried out on the ground state and many low-lying excited states of UFO to help interpret the photoelectron spectra and understand the electronic structure of UFO. The ground state of UFO(-) is linear with an O-U-F structure and a (3)H4 spectral term derived from a U 7sσ(2)5fφ(1)5fδ(1) electron configuration, whereas the ground state of neutral UFO has a (4)H(7/2) spectral term with a U 7sσ(1)5fφ(1)5fδ(1) electron configuration. Strong electron correlation effects are found in both the anionic and neutral electronic configurations. In the UFO neutral, a high density of electronic states with strong configuration mixing is observed in most of the scalar relativistic and spin-orbit coupled states. The strong electron correlation, state mixing, and spin-orbit coupling of the electronic states make the excited states of UFO very challenging for accurate quantum chemical calculations.
S. A. El-Wakil
2012-01-01
Full Text Available The reductive perturbation method has been employed to derive the Korteweg-de Vries (KdV equation for small- but finite-amplitude electrostatic ion-acoustic waves in weakly relativistic plasma consisting of warm ions and isothermal electrons. An algebraic method with computerized symbolic computation is applied in obtaining a series of exact solutions of the KdV equation. Numerical studies have been made using plasma parameters which reveal different solutions, that is, bell-shaped solitary pulses, rational pulses, and solutions with singularity at finite points, which called “blowup” solutions in addition to the propagation of an explosive pulses. The weakly relativistic effect is found to significantly change the basic properties (namely, the amplitude and the width of the ion-acoustic waves. The result of the present investigation may be applicable to some plasma environments, such as ionosphere region.
López, Rodrigo A. [Departamento de Física, Facultad de Ciencias Físicas y Matemáticas, Universidad de Concepción, Concepción 4070386 (Chile); Muñoz, Víctor [Departamento de Física, Facultad de Ciencias, Universidad de Chile, Casilla 653, Santiago (Chile); Viñas, Adolfo F. [Geospace Physics Laboratory, Heliophysics Science Division, NASA Goddard Space Flight Center, Greenbelt, Maryland 20771 (United States); Valdivia, Juan A. [Departamento de Física, Facultad de Ciencias, Universidad de Chile, Casilla 653, Santiago (Chile); Centro para el Desarrollo de la Nanociencia y la Nanotecnología (CEDENNA), Santiago 9170124 (Chile)
2015-09-15
We use a particle-in-cell simulation to study the propagation of localized structures in a magnetized electron-positron plasma with relativistic finite temperature. We use as initial condition for the simulation an envelope soliton solution of the nonlinear Schrödinger equation, derived from the relativistic two fluid equations in the strongly magnetized limit. This envelope soliton turns out not to be a stable solution for the simulation and splits in two localized structures propagating in opposite directions. However, these two localized structures exhibit a soliton-like behavior, as they keep their profile after they collide with each other due to the periodic boundary conditions. We also observe the formation of localized structures in the evolution of a spatially uniform circularly polarized Alfvén wave. In both cases, the localized structures propagate with an amplitude independent velocity.
Li, Xiaoze; Ye, Hu; Zhang, Yuchuan; Song, Wei; Su, Jiancang; Zhang, Ligang; Tan, Weibing; Hu, Xianggang; Zhu, Xiaoxin; Shen, Zhiyuan; Zhang, Min [Science and Technology on High Power Microwave Laboratory, Northwest Institute of Nuclear Technology, Xi' an 710024 (China)
2016-05-15
A high power capacity relativistic backward wave oscillator with an electron collection cavity (ECC) placed at the downstream of the slow wave structure (SWS) is presented. The breakdown threshold is increased, and the density of seed electron is suppressed by preventing the secondary electron, plasma, and powder generated from the bombardment of spent electron beam on the surface of the collector drifting to the extractor and beam-wave interaction region. The maximum longitudinal electric field in the device is reduced through extension of the span between electron beam and slow wave structure and weakening the Cerenkov radiation. The conversion efficiency reaches up to 52% owing to enhanced transit time radiation taking place at the entrance of the ECC. The maximum longitudinal electric field is 1.1 MV/cm on the surface of SWSs when the output power is 7.3 GW and the power capacity improves significantly.
Chen, H; Shepherd, R; Chung, H K; Dyer, G; Faenov, A; Fournier, K B; Hansen, S B; Hunter, J; Kemp, A; Pikuz, T; Ping, Y; Widmann, K; Wilks, S C; Beiersdorfer, P
2006-08-22
The authors have measured the relaxation time of hot electrons in short pulse laser-solid interactions using a picosecond time-resolved x-ray spectrometer and a time-integrated electron spectrometer. Employing laser intensities of 10{sup 17}, 10{sup 18}, and 10{sup 19} W/cm{sup 2}, they find increased laser coupling to hot electrons as the laser intensity becomes relativistic and thermalization of hot electrons at timescales on the order of 10 ps at all laser intensities. They propose a simple model based on collisional coupling and plasma expansion to describe the rapid relaxation of hot electrons. The agreement between the resulting K{sub {alpha}} time-history from this model with the experiments is best at highest laser intensity and less satisfactory at the two lower laser intensities.
Hramov, Alexander E; Morozov, Mikhail; Mushtakov, Alexander
2008-01-01
In this Letter we research the space charge limiting current value at which the oscillating virtual cathode is formed in the relativistic electron beam as a function of the external magnetic field guiding the beam electrons. It is shown that the space charge limiting (critical) current decreases with growth of the external magnetic field, and that there is an optimal induction value of the magnetic field at which the critical current for the onset of virtual cathode oscillations in the electron beam is minimum. For the strong external magnetic field the space charge limiting current corresponds to the analytical relation derived under the assumption that the motion of the electron beam is one-dimensional [High Power Microwave Sources. Artech House Microwave Library, 1987. Chapter~13]. Such behavior is explained by the characteristic features of the dynamics of electron space charge in the longitudinal and radial directions in the drift space at the different external magnetic fields.
Afanasjev, A. V.; König, J.; Ring, P.
1996-02-01
The cranked relativistic mean field approach is applied for a systematic investigation of superdeformed rotational bands observed in the A ˜ 140-150 mass region. The present investigation covers yrast and in some cases also excited superdeformed bands of all nuclei of this mass region in which such bands have been observed so far. Using the parameter set NL1, which has been adjusted ten years ago to a few spherical nuclei, reasonable agreement with experimental data is obtained throughout the mass region under investigation. It is shown that the calculated properties of superdeformed rotational bands such as the dependence of the dynamic moment of inertia J(2) with respect to the rotational frequency and the absolute value of the charge quadrupole moment Q0 depends sensitively on the number of occupied high- N intruder orbitals. This is agreement both with previous investigations within the cranked Nilsson-Strutinsky and the cranked Woods-Saxon-Strutinsky approaches and with available experimental data.
Turner, Drew; Mann, Ian; Usanova, Maria; Rodriguez, Juan; Henderson, Mike; Angelopoulos, Vassilis; Morley, Steven; Claudepierre, Seth; Li, Wen; Kellerman, Adam; Boyd, Alexander; Kim, Kyung-Chan
Earth’s outer electron radiation belt is a region of extreme variability, with relativistic electron intensities changing by orders of magnitude over time scales ranging from minutes to years. Extreme variations of outer belt electrons ultimately result from the relative impacts of various competing source (and acceleration), loss, and transport processes. Most of these processes involve wave-particle interactions between outer belt electrons and different types of plasma waves in the inner magnetosphere, and in turn, the activity of these waves depends on different solar wind and magnetospheric driving conditions and thus can vary drastically from event to event. Using multipoint analysis with data from NASA’s Van Allen Probes, THEMIS, and SAMPEX missions, NOAA’s GOES and POES constellations, and ground-based observatories, we present results from case studies revealing how different source/acceleration and loss mechanisms compete during active periods to result in drastically different distributions of outer belt electrons. By using a combination of low-Earth orbiting and high-altitude-equatorial orbiting satellites, we briefly review how it is possible to get a much more complete picture of certain wave activity and electron losses over the full range of MLTs and L-shells throughout the radiation belt. We then show example cases highlighting the importance of particular mechanisms, including: substorm injections and whistler-mode chorus waves for the source and acceleration of relativistic electrons; magnetopause shadowing and wave-particle interactions with EMIC waves for sudden losses; and ULF wave activity for driving radial transport, a process which is important for redistributing relativistic electrons, contributing both to acceleration and loss processes. We show how relativistic electron enhancement events involve local acceleration that is consistent with wave-particle interactions between a seed population of 10s to 100s of keV electrons, with a
Relativistic mean field study of the superdeformed rotational bands in the A {approx} 60 mass region
Madokoro, Hideki [Dept. of Physics, Kyushu Univ., Fukuoka (Japan); Matsuzaki, Masayuki
1999-03-01
The superdeformed rotational bands in {sup 62}Zn, which were recently discovered, are examined using Relativistic Mean Field model. The experimental dynamical moments of inertia and deformations are well reproduced, but the calculated bands which seem to correspond to the experimental data do not become yrast. This seems to be connected with the wrong position of the g{sup 9/2} single neutron orbit. (author)
Simulation of ultra-relativistic electrons and positrons channeling in crystals with MBN Explorer
Sushko, Gennady B.; Bezchastnov, Victor G.; Solov'yov, Ilia;
2013-01-01
A newly developed code, implemented as a part of the MBN Explorer package (Solov'yov et al., 2012; http://www.mbnexplorer.com/, 2012) [1] and [2] to simulate trajectories of an ultra-relativistic projectile in a crystalline medium, is presented. The motion of a projectile is treated classically...... by integrating the relativistic equations of motion with account for the interaction between the projectile and crystal atoms. The probabilistic element is introduced by a random choice of transverse coordinates and velocities of the projectile at the crystal entrance as well as by accounting for the random...
Xiong, Ying; Chen, Lunjin; Xie, Lun; Fu, Suiyan; Xia, Zhiyang; Pu, Zuyin
2017-05-01
Dayside modulated relativistic electron's butterfly pitch angle distributions (PADs) from ˜200 keV to 2.6 MeV were observed by Van Allen Probe B at L = 5.3 on 15 November 2013. They were associated with localized magnetic dip driven by hot ring current ion (60-100 keV proton and 60-200 keV helium and oxygen) injections. We reproduce the electron's butterfly PADs at satellite's location using test particle simulation. The simulation results illustrate that a negative radial flux gradient contributes primarily to the formation of the modulated electron's butterfly PADs through inward transport due to the inductive electric field, while deceleration due to the inductive electric field and pitch angle change also makes in part contribution. We suggest that localized magnetic field perturbation, which is a frequent phenomenon in the magnetosphere during magnetic disturbances, is of great importance for creating electron's butterfly PADs in the Earth's radiation belts.
Barik, N; Mohanty, D K; Panda, P K; Frederico, T
2013-01-01
We have calculated the properties of nuclear matter in a self-consistent manner with quark-meson coupling mechanism incorporating structure of nucleons in vacuum through a relativistic potential model; where the dominant confining interaction for the free independent quarks inside a nucleon, is represented by a phenomenologically average potential in equally mixed scalar-vector harmonic form. Corrections due to spurious centre of mass motion as well as those due to other residual interactions such as the one gluon exchange at short distances and quark-pion coupling arising out of chiral symmetry restoration; have been considered in a perturbation manner to obtain the nucleon mass in vacuum. The nucleon-nucleon interaction in nuclear matter is then realized by introducing additional quark couplings to sigma and omega mesons through mean field approximations. The relevant parameters of the interaction are obtained self consistently while realizing the saturation properties such as the binding energy, pressure a...
Pašteka, L. F.; Eliav, E.; Borschevsky, A.; Kaldor, U.; Schwerdtfeger, P.
2017-01-01
The first ionization potential (IP) and electron affinity (EA) of the gold atom have been determined to an unprecedented accuracy using relativistic coupled cluster calculations up to the pentuple excitation level including the Breit and QED contributions. We reach meV accuracy (with respect to the experimental values) by carefully accounting for all individual contributions beyond the standard relativistic coupled cluster approach. Thus, we are able to resolve the long-standing discrepancy between experimental and theoretical IP and EA of gold.
AlMuhammad, Anwar S
2002-01-01
Relying on the magnetic dipole model of the pulsar, we use the extension of the work of Haxton-Ruffini [31] for single charges by DePaolis-Ingrosso-Qadir [32] for an obliquely rotating magnetic dipole, to incorporate the effect of the gravitational mass. So, by using the numerical and analytical solutions of the differential equation for the radiation, we construct the energy spectra for different masses of the dipole-NS. These spectra show that, in relatively low angular momentum l, the effect of the gravitational mass is very significant in suppressing the relativistic enhancement factor, which had been found [27, 28, 32], by two to three orders of magnitude, as the mass changes from 0.5 solar mass to 3 solar masses. It is an indication that most of the angular momentum of the NS is retained as rotational kinetic energy instead of being radiated as an electromagnetic energy. Also, the suppressing in radiation energy is more or less independent of the angular momentum, and the high rotational velocity. We al...
Piot, P. [Northern Illinois Univ., DeKalb, IL (United States); Fermi National Accelerator Laboratory (FNAL), Batavia, IL (United States); Sun, Y. -E [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Maxwell, T. J. [Northern Illinois Univ., DeKalb, IL (United States); Fermi National Accelerator Laboratory (FNAL), Batavia, IL (United States); Ruan, J. [Fermi National Accelerator Laboratory (FNAL), Batavia, IL (United States); Lumpkin, A. H. [Fermi National Accelerator Laboratory (FNAL), Batavia, IL (United States); Rihaoui, M. M. [Northern Illinois Univ., DeKalb, IL (United States); Thurman-Keup, R. [Fermi National Accelerator Laboratory (FNAL), Batavia, IL (United States)
2011-06-27
We experimentally demonstrate the production of narrow-band (δf/f ~ =20% at f ~ = 0.5 THz) THz transition radiation with tunable frequency over [0.37, 0.86] THz. The radiation is produced as a train of sub-picosecond relativistic electron bunches transits at the vacuum-aluminum interface of an aluminum converter screen. In addition, we show a possible application of modulated beams to extend the dynamical range of a popular bunch length diagnostic technique based on the spectral analysis of coherent radiation.
Geloni, G; Schneidmiller, E; Yurkov, M V
2004-01-01
Longitudinal plasma oscillations are becoming a subject of great interest for XFEL physics in connection with LSC microbunching instability[1] and certain pump-probe synchronization schemes[2]. In the present paper we developed the first exact analytical treatment for longitudinal oscillations within an axis-symmetric, (relativistic) electron beam, which can be used as a primary standard for benchmarking space-charge simulation codes. Also, this result is per se of obvious theoretical relevance as it constitutes one of the few exact solutions for the evolution of charged particles under the action of self-interactions.
Plettner, Tomas; Colby, Eric R; Cowan, Benjamin; Sears, Chris M S; Siemann, Robert; Smith, Todd I; Spencer, James
2005-01-01
We have observed acceleration of relativistic electrons in vacuum driven by a linearly polarized laser beam incident on a thin gold-coated reflective boundary. The observed energy modulation effect follows all the characteristics expected for linear acceleration caused by a longitudinal electric field. As predicted by the Lawson-Woodward theorem the laser driven modulation only appears in the presence of the boundary. It shows a linear dependence with the strength of the electric field of the laser beam and also it is critically dependent on the laser polarization. Finally, it appears to follow the expected angular dependence of the inverse transition radiation process.
Haider, Md. Masum
2016-12-01
An attempt has been taken to find a general equation for degenerate pressure of Chandrasekhar and constants, by using which one can study nonrelativistic as well as ultra-relativistic cases instead of two different equations and constants. Using the general equation, ion-acoustic solitary and shock waves have been studied and compared, numerically and graphically, the two cases in same situation of electron-positron-ion plasmas. Korteweg-de Vries (KdV) and KdV-Barger equations have been derived as well as their solution to study the soliton and shock profiles, respectively.
Keith, Todd A; Frisch, Michael J
2011-11-17
Scalar-relativistic, all-electron density functional theory (DFT) calculations were done for free, neutral atoms of all elements of the periodic table using the universal Gaussian basis set. Each core, closed-subshell contribution to a total atomic electron density distribution was separately fitted to a spherical electron density function: a linear combination of s-type Gaussian functions. The resulting core subshell electron densities are useful for systematically and compactly approximating total core electron densities of atoms in molecules, for any atomic core defined in terms of closed subshells. When used to augment the electron density from a wave function based on a calculation using effective core potentials (ECPs) in the Hamiltonian, the atomic core electron densities are sufficient to restore the otherwise-absent electron density maxima at the nuclear positions and eliminate spurious critical points in the neighborhood of the atom, thus enabling quantum theory of atoms in molecules (QTAIM) analyses to be done in the neighborhoods of atoms for which ECPs were used. Comparison of results from QTAIM analyses with all-electron, relativistic and nonrelativistic molecular wave functions validates the use of the atomic core electron densities for augmenting electron densities from ECP-based wave functions. For an atom in a molecule for which a small-core or medium-core ECPs is used, simply representing the core using a simplistic, tightly localized electron density function is actually sufficient to obtain a correct electron density topology and perform QTAIM analyses to obtain at least semiquantitatively meaningful results, but this is often not true when a large-core ECP is used. Comparison of QTAIM results from augmenting ECP-based molecular wave functions with the realistic atomic core electron densities presented here versus augmenting with the limiting case of tight core densities may be useful for diagnosing the reliability of large-core ECP models in
Murphy, Gareth C; Bret, Antoine; Drury, Luke O'C; 10.1051/0004-6361/201015294
2010-01-01
The prompt emissions of gamma-ray bursts are seeded by radiating ultrarelativistic electrons. Internal shocks propagating through a jet launched by a stellar implosion, are expected to amplify the magnetic field & accelerate electrons. We explore the effects of density asymmetry & a quasi-parallel magnetic field on the collision of plasma clouds. A 2D relativistic PIC simulation models the collision of two plasma clouds, in the presence of a quasi-parallel magnetic field. The cloud density ratio is 10. The densities of ions & electrons & the temperature of 131 keV are equal in each cloud. The mass ratio is 250. The peak Lorentz factor of the electrons is determined, along with the orientation & strength of the magnetic field at the cloud collision boundary. The magnetic field component orthogonal to the initial plasma flow direction is amplified to values that exceed those expected from shock compression by over an order of magnitude. The forming shock is quasi-perpendicular due to this am...
H. Yoshitama; WEN Xian-Lun; WEN Tian-Shu; WU Yu-Chi; ZHANG Bao-San; ZHU Qi-Hua; HUANG Xiao-Jun; AN Wei-Min; HUNG Wen-Hui; TANG Chuan-Xiang; LIN Yu-Zheng; T. Kameshima; WANG Xiao-Dong; CHEN Li-Ming; H. Kotaki; M. Kando; K. Nakajima; GU Yu-Qiu; GUO Yi; JIAO Chun-Ye; LIU Hong-Jie; PENG Han-Sheng; TANG Chuan-Ming; WANG Xiao-Dong
2008-01-01
@@ Self-injection and acceleration of monoenergetic electron beams from laser wakefield accelerators are first in-vestigated in the highly relativistic regime, using 100 TW class, 27 fs laser pulses. Quasi-monoenergetic multi-bunched beams with energies as high as multi-hundredMeV are observed with simultaneous measurements of side-scattering emissions that indicate the formation of self-channelling and self-injection of electrons into a plasma wake, referred to as a 'bubble'. The three-dimensional particle-in-cell simulations confirmed multiple self-injection of electron bunches into the bubble and their beam acceleration with gradient of 1.5 GeV/cm.
Schächter, L; Kimura, W D
2015-05-15
Relativistic electrons counterpropagating through the center of a radially polarized J_{1} optical Bessel beam in vacuum will emit radiation in a manner analogous to the channeling radiation that occurs when charged particles traverse through a crystal lattice. However, since this interaction occurs in vacuum, problems with scattering of the electrons by the lattice atoms are eliminated. Contrary to inverse Compton scattering, the emitted frequency is also determined by the amplitude of the laser field, rather than only by its frequency. Adjusting the value of the laser field permits the tuning of the emitted frequency over orders of magnitude, from terahertz to soft X rays. High flux intensities are predicted (~100 MW/cm^{2}). Extended interaction lengths are feasible due to the diffraction-free properties of the Bessel beam and its radial field, which confines the electron trajectory within the center of the Bessel beam.
Hack, Szabolcs [ELI-ALPS, ELI-HU Non-Profit Ltd., Dugonics tér 13, H-6720 Szeged (Hungary); Department of Theoretical Physics, University of Szeged, Tisza L. krt. 84-86, H-6720 Szeged (Hungary); Varró, Sándor [ELI-ALPS, ELI-HU Non-Profit Ltd., Dugonics tér 13, H-6720 Szeged (Hungary); Wigner Research Center for Physics, SZFI, PO Box 49, H-1525 Budapest (Hungary); Czirják, Attila [ELI-ALPS, ELI-HU Non-Profit Ltd., Dugonics tér 13, H-6720 Szeged (Hungary); Department of Theoretical Physics, University of Szeged, Tisza L. krt. 84-86, H-6720 Szeged (Hungary)
2016-02-15
We investigate nonlinear Thomson scattering as a source of high-order harmonic radiation with the potential to enable attosecond light pulse generation. We present a new analytic solution of the electron’s relativistic equations of motion in the case of a short laser pulse with a sine-squared envelope. Based on the single electron emission, we compute and analyze the radiated amplitude and phase spectrum for a realistic electron bunch, with special attention to the correct initial values. These results show that the radiation spectrum of an electron bunch in head-on collision with a sufficiently strong laser pulse of sine-squared envelope has a smooth frequency dependence to allow for the synthesis of attosecond light pulses.
Dolya, S.N.; Zhidkov, E.P.; Rubin, S.B.; Semerdzhiev, Kh.I.
1982-01-01
The methodical work on creation of computer program for numerical study of the processes of forming and motion of a virtual cathode at the injection of relativistic electron beam into a short cylindrical chamber, filled with gas, has been carried out. The obtained plots of the distributions of fields, potential and density appearing out of ion and electron gas of the beam itself are presented. The dependence of cross-section ionization on the electron velocity has been taken into account at the calculation; the resonance contribution into summarized cross-section of ionization was simulated. It is shown that the injection into the chamber without gas, some oscillations of the virtual cathode are observed. At the presence of the final front of the beam, the fields level at the initial stage is smaller than for the beam with a sharp front. However, in some time the field amplitudes are compared. The motion of simulated probe ions in the chamber is analyzed.
Potekhin, A Yu
2000-01-01
The analytic equation of state of nonideal Coulomb plasmas consisting of pointlike ions immersed in a polarizable electron background (physics/9807042) is improved, and its applicability range is considerably extended. First, the fit of the electron screening contribution in the free energy of the Coulomb liquid is refined at high densities where the electrons are relativistic. Second, we calculate the screening contribution for the Coulomb solid (bcc and fcc) and derive an analytic fitting expression. Third, we propose a simple approximation to the internal and free energy of the liquid one-component plasma of ions, accurate within the numerical errors of the most recent Monte Carlo simulations. We obtain an updated value of the coupling parameter at the solid-liquid phase transition for the one-component plasma: Gamma_m = 175.0 (+/- 0.4).
Prakash, Bramha; Mishra, Ganeswar; Khullar, Roma
2016-03-01
In this paper spontaneous emission of radiation by relativistic electrons in a gyro-klystron is studied. The scheme consists of two solenoid sections separated by a dispersive section. In the dispersive section the electrons are made non-resonant with the radiation. The dispersive section transforms a small change of the velocity into changes of the phases of the electrons. This leads to enhanced radiation due to klystron-type modulation as compared with a conventional gyrotron-type device driven by cyclotron maser interaction. It is shown that the klystron-modulated spectrum depends on the dispersive field strength, finite perpendicular velocity component and length of the solenoids but is independent of the axial magnetic field strength. A simple scheme to design a gyro-klystron is discussed.
HE Xin-Kui; SHUAI Bin; GE Xiao-Chun; LI Ru-Xin; XU Zhi-Zhan
2004-01-01
@@ We investigate the influence of the initial laser phase on the interaction between relativistic electron and ultraintense linear polarized laser field in a strong uniform magnetic field. It is found that the dynamic behaviour of the relativistic electron and the emission spectrum varies dramatically with different initial laser field phases.The effect of changing initial phase is contrary in the two parameter regions divided by the resonance condition.The phase dependence of the electron energy and velocity components are also studied. Some beat structure is found when the initial laser phase is zero and this structure is absent when the initial laser phase is a quarter of a period.
Alam, M. S.; Hafez, M. G.; Talukder, M. R.; Hossain Ali, M.
2017-07-01
A comparative study of the interactions between nonlinear ion acoustic solitary waves (IASWs) propagating toward each other, and the electrostatic nonlinear propagation of IASWs, both for the weakly and relativistic regimes consisting of relativistic warm ions, nonthermal electrons, and positrons, is carried out. Two-sided Korteweg-de Vries (KdV) equations are derived using the extended Poincaré-Lighthill-Kuo (PLK) method to reveal the physical issues concerned. The effects of positron concentration, ion-electron temperature ratio, electron-positron temperature ratio, relativistic streaming factor, the population of electron, and positron nonthermality on the electrostatic resonances and their phase shifts are investigated for both regimes. It is found that the plasma parameters significantly modify the phase shifts, electrostatic resonances, hump-shaped electrostatic potential profiles, and the electric fields on the nonlinear propagation characteristics of IASWs. The results obtained may be useful for clarifications of interaction between IASWs in astrophysical and laboratory plasmas, especially in pulsar magnetosphere, laser produced, inertial confinement plasmas, and pulsar relativistic winds with supernova ejecta that produce nonthermal electrons, positrons, and relativistic ions.
Geng, L S; Meng, J
2005-01-01
We perform a systematic study of the ground-state properties of all the nuclei from the proton drip line to the neutron drip line throughout the periodic table employing the relativistic mean field model. The TMA parameter set is used for the mean-field Lagrangian density, and a state-dependent BCS method is adopted to describe the pairing correlation. The ground-state properties of a total of 6969 nuclei with $Z,N\\ge 8$ and $Z\\le 100$ from the proton drip line to the neutron drip line, including the binding energies, the separation energies, the deformations, and the rms charge radii, are calculated and compared with existing experimental data and those of the FRDM and HFB-2 mass formulae. This study provides the first complete picture of the current status of the descriptions of nuclear ground-state properties in the relativistic mean field model. The deviations from existing experimental data indicate either that new degrees of freedom are needed, such as triaxial deformations, or that serious effort is ne...
Zhong, J. Y.; Lin, J.; Li, Y. T.; Wang, X.; Li, Y.; Zhang, K.; Yuan, D. W.; Ping, Y. L.; Wei, H. G.; Wang, J. Q.; Su, L. N.; Li, F.; Han, B.; Liao, G. Q.; Yin, C. L.; Fang, Y.; Yuan, X.; Wang, C.; Sun, J. R.; Liang, G. Y.; Wang, F. L.; Ding, Y. K.; He, X. T.; Zhu, J. Q.; Sheng, Z. M.; Li, G.; Zhao, G.; Zhang, J.
2016-08-01
Laboratory experiments have been carried out to model the magnetic reconnection process in a solar flare with powerful lasers. Relativistic electrons with energy up to megaelectronvolts are detected along the magnetic separatrices bounding the reconnection outflow, which exhibit a kappa-like distribution with an effective temperature of ˜109 K. The acceleration of non-thermal electrons is found to be more efficient in the case with a guide magnetic field (a component of a magnetic field along the reconnection-induced electric field) than in the case without a guide field. Hardening of the spectrum at energies ≥500 keV is observed in both cases, which remarkably resembles the hardening of hard X-ray and γ-ray spectra observed in many solar flares. This supports a recent proposal that the hardening in the hard X-ray and γ-ray emissions of solar flares is due to a hardening of the source-electron spectrum. We also performed numerical simulations that help examine behaviors of electrons in the reconnection process with the electromagnetic field configurations occurring in the experiments. The trajectories of non-thermal electrons observed in the experiments were well duplicated in the simulations. Our numerical simulations generally reproduce the electron energy spectrum as well, except for the hardening of the electron spectrum. This suggests that other mechanisms such as shock or turbulence may play an important role in the production of the observed energetic electrons.
Gillingham, David R.
2007-12-01
The ability to preserve the quality of relativistic electron beams through transport bend elements such as a bunch compressor chicane is increasingly difficult as the current increases because of effects such as coherent synchrotron radiation (CSR) and space-charge. Theoretical CSR models and simulations, in their current state, often make unrealistic assumptions about the beam dynamics and/or structures. Therefore, we have developed a model and simulation that contains as many of these elements as possible for the purpose of making high-fidelity end-to-end simulations. Specifically, we are able to model, in a completely self-consistent, three-dimensional manner, the sustained interaction of radiation and space-charge from a relativistic electron beam in a toroidal waveguide with rectangular cross-section. We have accomplished this by combining a time-domain field solver that integrates a paraxial wave equation valid in a waveguide when the dimensions are small compared to the bending radius with a particle-in-cell dynamics code. The result is shown to agree with theory under a set of constraints, namely thin rigid beams, showing the stimulation resonant modes and including comparisons for waveguides approximating vacuum, and parallel plate shielding. Using a rigid beam, we also develop a scaling for the effect of beam width, comparing both our simulation and numerical integration of the retarded potentials. We further demonstrate the simulation calculates the correct longitudinal space-charge forces to produce the appropriate potential depression for a converging beam in a straight waveguide with constant dimensions. We then run fully three-dimensional, self-consistent end-to-end simulations of two types of bunch compressor designs, illustrating some of the basic scaling properties and perform a detailed analysis of the output phase-space distribution. Lastly, we show the unique ability of our simulation to model the evolution of charge/energy perturbations on a
Relativistic effects in two-particle emission for electron and neutrino reactions
Simo, I Ruiz; Amaro, J E; Barbaro, M B; Caballero, J A; Donnelly, T W
2014-01-01
Two-particle two-hole contributions to electroweak response functions are computed in a fully relativistic Fermi gas, assuming that the electroweak current matrix elements are independent of the kinematics. We analyze the genuine kinematical and relativistic effects before including a realistic meson-exchange current (MEC) operator. This allows one to study the mathematical properties of the non-trivial seven-dimensional integrals appearing in the calculation and to design an optimal numerical procedure to reduce the computation time. This is required for practical applications to CC neutrino scattering experiments, where an additional integral over the neutrino flux is performed. A check of the feasibility of this model using a more realistic current operator is presented for the case of the contact term of the electroweak MEC.
Sato, Masayasu; Isei, Nobuaki; Ishida, Sinichi [Japan Atomic Energy Research Inst., Naka, Ibaraki (Japan). Naka Fusion Research Establishment
1995-11-01
Effect of relativistic frequency down-shift on the determination of the electron temperature profile from electron cyclotron emission(ECE) in JT-60U tokamak plasmas is studied. The radial shift of the electron temperature profile due to the effects is not negligible, compared with the spatial resolution of ECE measurement systems of JT-60U. Therefore it is necessary to correct the effect for precise measurement of the electron temperature profile. Dependencies of the shifted frequency on the electron density, electron temperature and toroidal magnetic field are studied for the uniform electron density and parabolic electron temperature profile in JT-60U. It is revealed to be necessary for the estimation of shift due to the relativistic down-shift frequency to take into account of the optical thickness. (author).
Electron Ionization Mass Spectrum of Tellurium Hexafluoride
Clark, Richard A.; McNamara, Bruce K.; Barinaga, Charles J.; Peterson, James M.; Govind, Niranjan; Andersen, Amity; Abrecht, David G.; Schwantes, Jon M.; Ballou, Nathan E.
2015-05-18
The first electron ionization mass spectrum of tellurium hexafluoride (TeF6) is reported. The starting material was produced by direct fluorination of Te metal or TeO2 with nitrogen trifluoride. Formation of TeF6 was confirmed through cryogenic capture of the tellurium fluorination product and analysis through Raman spectroscopy. The eight natural abundance isotopes were observed for each of the set of fragment ions: TeF5+, TeF4+ TeF3+, TeF2+, TeF1+, and Te+, Te2+. A trend in increasing abundance was observed for the even fluoride bearing ions: TeF1+ < TeF3+ < TeF5+, and a decreasing abundance was observed for the even fragment series: Te(0)+ > TeF2+ > TeF4+ > TeF6+, with the molecular ion TeF6+ not observed at all. Density functional theory based electronic structure calculations were used to calculate optimized ground state geometries of these gas phase species and their relative stabilities explain the trends in the data and the lack of observed signal for TeF6+.
Electron ionization mass spectrum of tellurium hexafluoride.
Clark, Richard A; McNamara, Bruce K; Barinaga, Charles J; Peterson, James M; Govind, Niranjan; Andersen, Amity; Abrecht, David G; Schwantes, Jon M; Ballou, Nathan E
2015-05-18
The electron ionization mass spectrum of tellurium hexafluoride (TeF6) is reported for the first time. The starting material was produced by direct fluorination of Te metal or TeO2 with nitrogen trifluoride. Formation of TeF6 was confirmed through cryogenic capture of the tellurium fluorination product and analysis through Raman spectroscopy. The eight natural abundance isotopes were observed for each of the set of fragment ions: TeF5(+), TeF4(+) TeF3(+), TeF2(+), TeF1(+), and Te(+), Te2(+). A trend in increasing abundance was observed for the odd fluoride bearing ions, TeF1(+) TeF2(+) > TeF4(+) > TeF6(+), with the molecular ion TeF6(+) not observed at all. Density functional theory based electronic structure calculations were used to calculate optimized ground state geometries of these gas phase species, and their relative stabilities explain the trends in the data and the lack of observed signal for TeF6(+).
TENTATIVE EVIDENCE FOR RELATIVISTIC ELECTRONS GENERATED BY THE JET OF THE YOUNG SUN-LIKE STAR DG Tau
Ainsworth, Rachael E.; Ray, Tom P.; Taylor, Andrew M. [Dublin Institute for Advanced Studies, 31 Fitzwilliam Place, Dublin 2 (Ireland); Scaife, Anna M. M. [School of Physics and Astronomy, University of Southampton, Highfield, Southampton, SO17 1BJ (United Kingdom); Green, David A.; Buckle, Jane V., E-mail: rainsworth@cp.dias.ie [Cavendish Laboratory, J J Thomson Avenue, Cambridge, CB3 0HE (United Kingdom)
2014-09-01
Synchrotron emission has recently been detected in the jet of a massive protostar, providing further evidence that certain jet formation characteristics for young stars are similar to those found for highly relativistic jets from active galactic nuclei. We present data at 325 and 610 MHz taken with the Giant Metrewave Radio Telescope of the young, low-mass star DG Tau, an analog of the Sun soon after its birth. This is the first investigation of a low-mass young stellar object at such low frequencies. We detect emission with a synchrotron spectral index in the proximity of the DG Tau jet and interpret this emission as a prominent bow shock associated with this outflow. This result provides tentative evidence for the acceleration of particles to relativistic energies due to the shock impact of this otherwise very low-power jet against the ambient medium. We calculate the equipartition magnetic field strength B {sub min} ≈ 0.11 mG and particle energy E {sub min} ≈ 4 × 10{sup 40} erg, which are the minimum requirements to account for the synchrotron emission of the DG Tau bow shock. These results suggest the possibility of low energy cosmic rays being generated by young Sun-like stars.
Exact Relativistic 'Antigravity' Propulsion
Felber, F S
2006-01-01
The Schwarzschild solution is used to find the exact relativistic motion of a payload in the gravitational field of a mass moving with constant velocity. At radial approach or recession speeds faster than 3^-1/2 times the speed of light, even a small mass gravitationally repels a payload. At relativistic speeds, a suitable mass can quickly propel a heavy payload from rest nearly to the speed of light with negligible stresses on the payload.
Exact Relativistic `Antigravity' Propulsion
Felber, Franklin S.
2006-01-01
The Schwarzschild solution is used to find the exact relativistic motion of a payload in the gravitational field of a mass moving with constant velocity. At radial approach or recession speeds faster than 3-1/2 times the speed of light, even a small mass gravitationally repels a payload. At relativistic speeds, a suitable mass can quickly propel a heavy payload from rest nearly to the speed of light with negligible stresses on the payload.
Point form relativistic quantum mechanics and relativistic SU(6)
Klink, W. H.
1993-01-01
The point form is used as a framework for formulating a relativistic quantum mechanics, with the mass operator carrying the interactions of underlying constituents. A symplectic Lie algebra of mass operators is introduced from which a relativistic harmonic oscillator mass operator is formed. Mass splittings within the degenerate harmonic oscillator levels arise from relativistically invariant spin-spin, spin-orbit, and tensor mass operators. Internal flavor (and color) symmetries are introduced which make it possible to formulate a relativistic SU(6) model of baryons (and mesons). Careful attention is paid to the permutation symmetry properties of the hadronic wave functions, which are written as polynomials in Bargmann spaces.
Beneke, M; Ruiz-Femenia, P
2014-01-01
This paper concludes the presentation of the non-relativistic effective field theory formalism designed to calculate the radiative corrections that enhance the pair-annihilation cross sections of slowly moving neutralinos and charginos within the general minimal supersymmetric standard model (MSSM). While papers I and II focused on the computation of the tree-level annihilation rates that feed into the short-distance part, here we describe in detail the method to obtain the Sommerfeld factors that contain the enhanced long-distance corrections. This includes the computation of the potential interactions in the MSSM, which are provided in compact analytic form, and a novel solution of the multi-state Schr\\"odinger equation that is free from the numerical instabilities generated by large mass splittings between the scattering states. Our results allow for a precise computation of the MSSM neutralino dark matter relic abundance and pair-annihilation rates in the present Universe, when Sommerfeld enhancements are...
Zhang, Lin-Feng; Xia, Xue-Wei
2016-05-01
The α-decay energies (Q α ) are systematically investigated with the nuclear masses for 10 ⩽ Z ⩽ 120 isotopes obtained by the relativistic continuum Hartree-Bogoliubov (RCHB) theory with the covariant density functional PC-PK1, and compared with available experimental values. It is found that the α-decay energies deduced from the RCHB results present a similar pattern to those from available experiments. Owing to the large predicted Q α values (⩾ 4 MeV), many undiscovered heavy nuclei in the proton-rich side and super-heavy nuclei may have large possibilities for α-decay. The influence of nuclear shell structure on α-decay energies is also analysed. Supported by Major State 973 Program of China (2013CB834400), National Natural Science Foundation of China (11175002, 11335002, 11375015, 11461141002), Research Fund for the Doctoral Program of Higher Education (20110001110087) and National Undergraduate Innovation Training Programs of Peking University.
Tabrizi, Mehdi
2016-10-01
The multiple scattering effect on the linewidth of backward Parametric X-ray Radiation (PXR) produced in the extremely Bragg geometry by low energy relativistic electrons traversing a single crystal is discussed. It is shown that there are conditions when the influence of photoabsorption on the linewidth can be neglected, and only the multiple scattering process of relativistic electrons in crystals leads to the PXR lines broadening. Based on obtained theoretical and numerical results for the linewidth broadening caused by multiple scattering of 30 and 50 MeV relativistic electrons in a Si crystal of various thicknesses, an experiment could be performed to help in revealing the scattering effect on the PXR lines in the absence of photoabsorption. This leads to more accurate understanding of the influence of scattering process on the linewidth of backward PXR and helps to better construct a table-top narrow bandwidth X-ray source for both scientific and industrial applications.
Bubin, Sergiy; Komasa, Jacek; Stanke, Monika; Adamowicz, Ludwik
2010-03-01
We present very accurate quantum mechanical calculations of the three lowest S-states [1s22s2(S10), 1s22p2(S10), and 1s22s3s(S10)] of the two stable isotopes of the boron ion, B10+ and B11+. At the nonrelativistic level the calculations have been performed with the Hamiltonian that explicitly includes the finite mass of the nucleus as it was obtained by a rigorous separation of the center-of-mass motion from the laboratory frame Hamiltonian. The spatial part of the nonrelativistic wave function for each state was expanded in terms of 10 000 all-electron explicitly correlated Gaussian functions. The nonlinear parameters of the Gaussians were variationally optimized using a procedure involving the analytical energy gradient determined with respect to the nonlinear parameters. The nonrelativistic wave functions of the three states were subsequently used to calculate the leading α2 relativistic corrections (α is the fine structure constant; α =1/c, where c is the speed of light) and the α3 quantum electrodynamics (QED) correction. We also estimated the α4 QED correction by calculating its dominant component. A comparison of the experimental transition frequencies with the frequencies obtained based on the energies calculated in this work shows an excellent agreement. The discrepancy is smaller than 0.4 cm-1.
Bubin, Sergiy; Komasa, Jacek; Stanke, Monika; Adamowicz, Ludwik
2010-03-21
We present very accurate quantum mechanical calculations of the three lowest S-states [1s(2)2s(2)((1)S(0)), 1s(2)2p(2)((1)S(0)), and 1s(2)2s3s((1)S(0))] of the two stable isotopes of the boron ion, (10)B(+) and (11)B(+). At the nonrelativistic level the calculations have been performed with the Hamiltonian that explicitly includes the finite mass of the nucleus as it was obtained by a rigorous separation of the center-of-mass motion from the laboratory frame Hamiltonian. The spatial part of the nonrelativistic wave function for each state was expanded in terms of 10,000 all-electron explicitly correlated Gaussian functions. The nonlinear parameters of the Gaussians were variationally optimized using a procedure involving the analytical energy gradient determined with respect to the nonlinear parameters. The nonrelativistic wave functions of the three states were subsequently used to calculate the leading alpha(2) relativistic corrections (alpha is the fine structure constant; alpha=1/c, where c is the speed of light) and the alpha(3) quantum electrodynamics (QED) correction. We also estimated the alpha(4) QED correction by calculating its dominant component. A comparison of the experimental transition frequencies with the frequencies obtained based on the energies calculated in this work shows an excellent agreement. The discrepancy is smaller than 0.4 cm(-1).
Semi empirical formula to calculate MSP of relativistic electrons in the range of 940 keV–1020 keV
S. Ramesh Babu
2016-01-01
Full Text Available A semi empirical formula has been obtained to calculate the Mass stopping power (MSP of relativistic electrons in the energy range of 950 keV–1050 keV, for any material of atomic number or Zeff ranging from 10–82. The MSP of 942 keV and 1016 keV internal conversion electrons of Bi207 are obtained by allowing them to pass through the targets of atomic numbers 13, 29, 47, 50, 79 and 82. The energies of the incident and transmitted electrons are measured using a Si(Li detector coupled to 8 K multi channel analyzer and the MSP has been determined from the measured incident and transmitted energies. The resultant variation of MSP with the atomic number of the material is plotted and best fitted to a first order exponential equation. The results predicted by this semi empirical formula are compared with the NIST-ESTAR database & Batra's formula and found to be in good agreement. Application of this formula to calculate the MSP and effective atomic number of any biological sample or compound is discussed.
Bodek, K.; Kępka, D.; Rozpędzik, D.; Zejma, J.; Kozela, A.
2017-04-01
A self-calibrating double-Mott polarimeter is proposed for measurement of the spin correlation function of relativistic electron pairs produced in Møller scattering. The polarization of outgoing electrons (appearing when the beam is polarized) is utilized for calibration of effective analyzing powers in the secondary Mott scattering used for spin analysis. The experiment will measure the newly introduced relative spin correlation function. This new observable can be measured with a significantly better accuracy than the regular spin correlation function in a small scale experiment. It is shown that both the spin correlation function and the relative spin correlation function are theoretically equivalent. A specific experimental data analysis scenario is proposed, which effectively eliminates the systematic effects related to the imperfect geometry and detector efficiency.
Kim, Kyung-Chan; Shprits, Yuri; Subbotin, Dmitriy; Ni, Binbin
2012-08-01
Understanding the dynamics of relativistic electron acceleration, loss, and transport in the Earth's radiation belt during magnetic storms is a challenging task. The U.S. National Science Foundation's Geospace Environment Modeling (GEM) has identified five magnetic storms for in-depth study that occurred during the second half of the Combined Release and Radiation Effects Satellite (CRRES) mission in the year 1991. In this study, we show the responses of relativistic radiation belt electrons to the magnetic storms by comparing the time-dependent 3-D Versatile Electron Radiation Belt (VERB) simulations with the CRRES MEA 1 MeV electron observations in order to investigate the relative roles of the competing effects of previously proposed scattering mechanisms at different storm phases, as well as to examine the extent to which the simulations can reproduce observations. The major scattering processes in our model are radial transport due to Ultra Low Frequency (ULF) electromagnetic fluctuations, pitch angle and energy diffusion including mixed diffusion by whistler mode chorus waves outside the plasmasphere, and pitch angle scattering by plasmaspheric hiss inside the plasmasphere. The 3-D VERB simulations show that during the storm main phase and early recovery phase the estimated plasmapause is located deep in the inner region, indicating that pitch angle scattering by chorus waves can be a dominant loss process in the outer belt. We have also confirmed the important role played by mixed energy-pitch angle diffusion by chorus waves, which tends to reduce the fluxes enhanced by local acceleration, resulting in comparable levels of computed and measured fluxes. However, we cannot reproduce the more pronounced flux dropout near the boundary of our simulations during the main phase, which indicates that non-adiabatic losses may extend toL-shells lower than our simulation boundary. We also provide a detailed description of simulations for each of the GEM storm events.
Dieckmann, M. E.; Sarri, G.; Markoff, S.; Borghesi, M.; Zepf, M.
2015-05-01
Context. The jets of compact accreting objects are composed of electrons and a mixture of positrons and ions. These outflows impinge on the interstellar or intergalactic medium and both plasmas interact via collisionless processes. Filamentation (beam-Weibel) instabilities give rise to the growth of strong electromagnetic fields. These fields thermalize the interpenetrating plasmas. Aims: Hitherto, the effects imposed by a spatial non-uniformity on filamentation instabilities have remained unexplored. We examine the interaction between spatially uniform background electrons and a minuscule cloud of electrons and positrons. The cloud size is comparable to that created in recent laboratory experiments and such clouds may exist close to internal and external shocks of leptonic jets. The purpose of our study is to determine the prevalent instabilities, their ability to generate electromagnetic fields and the mechanism, by which the lepton micro-cloud transfers energy to the background plasma. Methods: A square micro-cloud of equally dense electrons and positrons impinges in our particle-in-cell (PIC) simulation on a spatially uniform plasma at rest. The latter consists of electrons with a temperature of 1 keV and immobile ions. The initially charge- and current neutral micro-cloud has a temperature of 100 keV and a side length of 2.5 plasma skin depths of the micro-cloud. The side length is given in the reference frame of the background plasma. The mean speed of the micro-cloud corresponds to a relativistic factor of 15, which is relevant for laboratory experiments and for relativistic astrophysical outflows. The spatial distributions of the leptons and of the electromagnetic fields are examined at several times. Results: A filamentation instability develops between the magnetic field carried by the micro-cloud and the background electrons. The electromagnetic fields, which grow from noise levels, redistribute the electrons and positrons within the cloud, which boosts
Barik, N.; Mishra, R. N.; Mohanty, D. K.; Panda, P. K.; Frederico, T.
2013-07-01
We have calculated the properties of nuclear matter in a self-consistent manner with a quark-meson coupling mechanism incorporating the structure of nucleons in vacuum through a relativistic potential model; where the dominant confining interaction for the free independent quarks inside a nucleon is represented by a phenomenologically average potential in equally mixed scalar-vector harmonic form. Corrections due to spurious center of mass motion as well as those due to other residual interactions, such as the one gluon exchange at short distances and quark-pion coupling arising out of chiral symmetry restoration, have been considered in a perturbative manner to obtain the nucleon mass in vacuum. The nucleon-nucleon interaction in nuclear matter is then realized by introducing additional quark couplings to σ and ω mesons through mean field approximations. The relevant parameters of the interaction are obtained self-consistently while realizing the saturation properties such as the binding energy, pressure, and compressibility of the nuclear matter. We also discuss some implications of chiral symmetry in nuclear matter along with the nucleon and nuclear σ term and the sensitivity of nuclear matter binding energy with variations in the light quark mass.
Afanasjev, A.V. [Technische Univ. Muenchen, Garching (Germany). Physik-Department]|[Latvian Acad. of Sci., Salaspils (Latvia). Dept. of Math. Phys.]|[Lund Inst. of Tech. (Sweden). Dept. of Mathematical Physics; Koenig, J. [Technische Univ. Muenchen, Garching (Germany). Physik-Department; Ring, P. [Technische Univ. Muenchen, Garching (Germany). Physik-Department
1996-10-14
The cranked relativistic mean field approach is applied for a systematic investigation of superdeformed rotational bands observed in the A {proportional_to}140-150 mass region. The present investigation covers yrast and in some cases also excited superdeformed bands of all nuclei of this mass region in which such bands have been observed so far. Using the parameter set NL1, which has been adjusted ten years ago to a few spherical nuclei, reasonable agreement with experimental data is obtained throughout the mass region under investigation. It is shown that the calculated properties of superdeformed rotational bands such as the dependence of the dynamic moment of inertia J{sup (2)} with respect to the rotational frequency and the absolute value of the charge quadrupole moment Q{sub 0} depends sensitively on the number of occupied high-N intruder orbitals. This is in agreement both with previous investigations within the cranked Nilsson-Strutinsky and the cranked Woods-Saxon-Strutinsky approaches and with available experimental data. (orig.).
Skripnikov, L. V.
2016-12-01
A precise theoretical study of the electronic structure of heavy atom diatomic molecules is of key importance to interpret the experiments in the search for violation of time-reversal (T) and spatial-parity (P) symmetries of fundamental interactions in terms of the electron electric dipole moment, eEDM, and dimensionless constant, kT,P, characterizing the strength of the T,P-odd pseudoscalar-scalar electron-nucleus neutral current interaction. The ACME collaboration has recently improved limits on these quantities using a beam of ThO molecules in the electronic H3Δ1 state [J. Baron et al., Science 343, 269 (2014)]. We apply the combined direct relativistic 4-component and two-step relativistic pseudopotential/restoration approaches to a benchmark calculation of the effective electric field, Eeff, parameter of the T,P-odd pseudoscalar-scalar interaction, WT,P, and hyperfine structure constant in Δ31 state of the ThO molecule. The first two parameters are required to interpret the experimental data in terms of the eEDM and kT,P constant. We have investigated the electron correlation for all of the 98 electrons of ThO simultaneously up to the level of the coupled cluster with single, double, and noniterative triple amplitudes, CCSD(T), theory. Contributions from iterative triple and noniterative quadruple cluster amplitudes for the valence electrons have been also treated. The obtained values are Eeff = 79.9 GV/cm, WT,P = 113.1 kHz. The theoretical uncertainty of these values is estimated to be about two times smaller than that of our previous study [L. V. Skripnikov and A. V. Titov, J. Chem. Phys., 142, 024301 (2015)]. It was found that the correlation of the inner- and outer-core electrons contributes 9% to the effective electric field. The values of the molecule frame dipole moment of the Δ31 state and the H3Δ1 →X1Σ+ transition energy of ThO calculated within the same methods are in a very good agreement with the experiment.
Kakuwa, Jun; Asano, Katsuaki; Kusunose, Masaaki; Takahara, Fumio
2015-01-01
We examine the applicability of the stochastic electron acceleration to two high synchrotron peaked blazars, Mrk 421 and Mrk 501, assuming synchrotron self-Compton emission of gamma-rays. Our model considers an emitting region moving at relativistic speed, where non-thermal electrons are accelerated and attain a steady-state energy spectrum together with the photons they emit. The kinetic equations of the electrons and photons are solved numerically, given a stationary wave number spectrum of the magnetohydrodynamic (MHD) disturbances, which are responsible for the electron acceleration and escape. Our simple formulation appears to reproduce the two well-sampled, long-term averaged photon spectra. In order to fit the model to the emission component from the radio to the X-ray bands, we need both a steeper wave spectral index than the Kolmogorov spectrum and efficient particle escape. Although the model provides a natural explanation for the high-energy cutoff of the electron energy distribution, the derived p...
Magnetic properties of f-electron systems in spin-polarized relativistic density functional theory
Yamagami, H.; Mavromaras, A.; Kübler, J.
1997-12-01
The magnetic ground state of the series of lanthanide and actinide trivalent ions is investigated by means of spin-polarized relativistic spin-density functional theory. In the local density functional approximation (LDA) an internal effective magnetic field due to exchange and correlation couples to the spin degrees of freedom. The resulting set of coupled Dirac equations yields ground-state multiplets that obey the well-known Hund's rules. This remarkable result comes about by the coupling of the j = l + 1/2 with the j = l - 1/2 states due to the exchange - correlation potential that is, as usual, the functional derivative of the exchange - correlation energy with respect to the spin magnetic moment. The effect of the coupling is shown to depend on the varying relative strengths of spin - orbit coupling and exchange splitting within the f series. Since in the f levels the internal exchange splitting dominates rather than the spin - orbit splitting, the energy level scheme is that of the Paschen - Back effect, and thus features of the Russell - Saunders coupling persist in spite of relativistic effects.
Faure, Jérôme; Guénot, Diego; Gustas, Dominykas; Vernier, Aline; Beaurepaire, Benoît; Böhle, Frederik; López-Martens, Rodrigo; Lifschitz, Agustin
2017-05-01
Laser-plasma accelerators are usually driven by 100-TW class laser systems with rather low repetition rates. However, recent years have seen the emergence of laser-plasma accelerators operating with kHz lasers and energies lower than 10 mJ. The high repetition-rate is particularly interesting for applications requiring high stability and high signal-to-noise ratio but lower energy electrons. For example, our group recently demonstrated that kHz laser-driven electron beams could be used to capture ultrafast structural dynamics in Silicon nano-membranes via electron diffraction with picosecond resolution. In these first experiments, electrons were injected in the density gradients located at the plasma exit, resulting in rather low energies in the 100 keV range. The electrons being nonrelativistic, the bunch duration quickly becomes picosecond long. Relativistic energies are required to mitigate space charge effects and maintain femtosecond bunches. In this paper, we will show very recent results where electrons are accelerated in laser-driven wakefields to relativistic energies, reaching up to 5 MeV at kHz repetition rate. The electron energy was increased by nearly two orders of magnitude by using single-cycle laser pulses of 3.5 fs, with only 2.5 mJ of energy. Using such short pulses of light allowed us to resonantly excite high amplitude and nonlinear plasma waves at high plasma density, ne=1.5-2×1020 cm-3, in a regime close to the blow-out regime. Electrons had a peaked distribution around 5 MeV, with a relative energy spread of 30 %. Charges in the 100's fC/shot and up to pC/shot where measured depending on plasma density. The electron beam was fairly collimated, 20 mrad divergence at Full Width Half Maximum. The results show remarkable stability of the beam parameters in terms of beam pointing and electron distribution. 3D PIC simulations reproduce the results very well and indicate that electrons are injected by the ionization of Nitrogen atoms, N5+ to N6
Magnetic Moment Fields in Dense Relativistic Plasma Interacting with Laser Radiations
B.Ghosh1* , S.N.Paul 1 , S.Bannerjee2 and C.Das3
2013-04-01
Full Text Available Theory of the generation of magnetic moment field from resonant interaction of three high frequency electromagnetic waves in un-magnetized dense electron plasma is developed including the relativistic change of electron mass. It is shown that the inclusion of relativistic effect enhances the magnetic moment field. For high intensity laser beams this moment field may be of the order of a few mega gauss. Such a high magnetic field can considerably affect the transport of electrons in fusion plasma
Stormtime Dynamics of the Relativistic Electron Flux in Earth's Radiation Belts
Vassiliadis, D.
2011-01-01
A state-vector representation is a powerful technique for describing complex plasma systems. Its framework can be adapted for classification methods which can be used to analyze the system's history and for prediction methods which can serve to forecast its future activity. A state-vector description is developed for the electron flux dynamics in Earth's radiation belts, based on an 11-year (1993-2003) dataset of high-cadence flux measurements from a low-Earth (SAMPEX) orbit over a wide L range and at a fixed energy (2-6 MeV). A clustering algorithm is used to divide the state space into regions, or clusters of vectors, and it becomes evident that flux intensifications during storms correspond to characteristic transitions in state space following geoeffective interplanetary disturbances (such as interplanetary coronal mass ejections and high-speed streams). Examples are discussed to show that the classification is valid for medium-term (several-days) and long-term (solar-cycle-phase) timescales. The state-vector representation is then used as the basis of a predictive model of the flux distribution given upstream solar wind measurements. It is found that model accuracy of storm prediction is maximized if the model is tuned at a highly nonlinear regime. The relation to earlier state representations and models of the radiation belt flux is discussed.
'Antigravity' Propulsion and Relativistic Hyperdrive
Felber, F S
2006-01-01
Exact payload trajectories in the strong gravitational fields of compact masses moving with constant relativistic velocities are calculated. The strong field of a suitable driver mass at relativistic speeds can quickly propel a heavy payload from rest to a speed significantly faster than the driver, a condition called hyperdrive. Hyperdrive thresholds and maxima are calculated as functions of driver mass and velocity.
Phillips, D R; Devine, N K
1998-01-01
The electromagnetic interactions of a relativistic two-body bound state are formulated in three dimensions using an equal-time (ET) formalism. This involves a systematic reduction of four-dimensional dynamics to a three-dimensional form by integrating out the time components of relative momenta. A conserved electromagnetic current is developed for the ET formalism. It is shown that consistent truncations of the electromagnetic current and the $NN$ interaction kernel may be made, order-by-order in the coupling constants, such that appropriate Ward-Takahashi identities are satisfied. A meson-exchange model of the $NN$ interaction is used to calculate deuteron vertex functions. Calculations of electromagnetic form factors for elastic scattering of electrons by deuterium are performed using an impulse-approximation current. Negative-energy components of the deuteron's vertex function and retardation effects in the meson-exchange interaction are found to have only minor effects on the deuteron form factors.
Lu, Ding; Xie, Bai-Song
2013-01-01
Effects of ion mobility and positron fraction on solitary waves of envelop of laser field and potential of electrostatic field in weak relativistic electron-positron-ion plasma are investigated. The parameter region for the existence of solitary waves is obtained analytically, and the reasonable choice of parameters is clarified. Both cases of mobile and immobile ions are considered. It is found that the amplitudes of solitary waves in the former case are larger compared to the latter case. For small plasma density, the localized solitary wave solutions in terms of approximate perturbation analytical method are consistent well with that by exact numerical calculations. However as the plasma density increases the analytical method loses its validity more and more. The influence of the positron fraction on the amplitudes of solitary waves shows a monotonous increasing relation. Implication of our results to the particle acceleration is also discussed briefly.
Lu, Ding; Li, Zi-Liang; Xie, Bai-Song
2013-09-01
The effects of ion mobility and positron fraction on the solitary waves of the laser field envelope and the potential of the electrostatic field in weak relativistic electron-positron-ion plasma are investigated. The parameter region for the existence of solitary waves is obtained analytically, and a reasonable choice of parameters is clarified. Both cases of mobile and immobile ions are considered. It is found that the amplitudes of solitary waves in the former case are larger compared to the latter case. For small plasma density, the localized solitary wave solutions in terms of the approximate perturbation analytical method are very consistent with those by exact numerical calculations. However, as the plasma density increases the analytical method loses its validity more and more. The influence of the positron fraction on the amplitudes of solitary waves shows a monotonous increasing relation. The implications of our results to particle acceleration are also discussed briefly.
Dunning, Michael
2012-07-19
We report generation of density modulation at terahertz (THz) frequencies in a relativistic electron beam through laser modulation of the beam longitudinal phase space. We show that by modulating the energy distribution of the beam with two lasers, density modulation at the difference frequency of the two lasers can be generated after the beam passes through a chicane. In this experiment, density modulation around 10 THz was generated by down-converting the frequencies of an 800 nm laser and a 1550 nm laser. The central frequency of the density modulation can be tuned by varying the laser wavelengths, beam energy chirp, or momentum compaction of the chicane. This technique can be applied to accelerator-based light sources for generation of coherent THz radiation and marks a significant advance toward tunable narrow-band THz sources.
Influence of binding energies of electrons on nuclear mass predictions
Tang, Jing; Niu, Zhong-Ming; Guo, Jian-You
2016-07-01
Nuclear mass contains a wealth of nuclear structure information, and has been widely employed to extract the nuclear effective interactions. The known nuclear mass is usually extracted from the experimental atomic mass by subtracting the masses of electrons and adding the binding energy of electrons in the atom. However, the binding energies of electrons are sometimes neglected in extracting the known nuclear masses. The influence of binding energies of electrons on nuclear mass predictions are carefully investigated in this work. If the binding energies of electrons are directly subtracted from the theoretical mass predictions, the rms deviations of nuclear mass predictions with respect to the known data are increased by about 200 keV for nuclei with Z, N ⩾ 8. Furthermore, by using the Coulomb energies between protons to absorb the binding energies of electrons, their influence on the rms deviations is significantly reduced to only about 10 keV for nuclei with Z, N ⩾ 8. However, the binding energies of electrons are still important for the heavy nuclei, about 150 keV for nuclei around Z = 100 and up to about 500 keV for nuclei around Z = 120. Therefore, it is necessary to consider the binding energies of electrons to reliably predict the masses of heavy nuclei at an accuracy of hundreds of keV. Supported by National Natural Science Foundation of China (11205004)
The impact of kinetic effects on the properties of relativistic electron-positron shocks
Stockem, A; Fonseca, R A; Silva, L O
2012-01-01
We assess the impact of non-thermally shock-accelerated particles on the magnetohydrodynamic (MHD) jump conditions of relativistic shocks. The adiabatic constant is calculated directly from first principle particle-in-cell simulation data, enabling a semi-kinetic approach to improve the standard fluid model and allowing for an identification of the key parameters that define the shock structure. We find that the evolving upstream parameters have a stronger impact than the corrections due to non-thermal particles. We find that the decrease of the upstream bulk speed yields deviations from the standard MHD model up to 10%. Furthermore, we obtain a quantitative definition of the shock transition region from our analysis. For Weibel-mediated shocks the inclusion of a magnetic field in the MHD conservation equations is addressed for the first time.
郑金磊; 钟秋珍; 陈良旭; 刘四清; 丁铸
2012-01-01
The relativistic electron flux enhancement event at GEO in April 2010 is analyzed in contrasting with other 6 similar events from 2004 to 2010. Solar wind and geomagnetic conditionswhich might trigger this event were analyzed. Analytical results indicate that the relatively weaker magnetic storms were prone to make the high flux part of relativistic electrons closer to GEO orbit, and whistler wave acceleration mechanism probably played important roles. The injection depth of seed electrons was closely related to magnetic storm intensity. Dst index curve is well fitted with the lower edge of higher flux region of 30-100keV electrons. The injection depth of seed electrons determined the region where mass of 〉 300 keV electrons appeared. Because of the relatively weak storms in the relativistic electron flux enhancement event, the seed electrons injected into a shallow region which was close to geosynchronous orbit, leading to relativistic electron flux abnormally enhancement in geosynchronous orbit. The intense substorms in relativistic electron flux enhancement event at GEO in April 2010, which generated sufficient seed electrons and enhanced the wave-particle interaction, was an essential factor leading to relativistic electrons flux enhancement.%为研究2010年4月地球同步轨道相对论电子通量异常增强事件的原因，选取了2004-2010年之间高速太阳风下7个类似事件进行对比分析．探讨了多种可能导致此次异常事件的太阳风和地磁条件．结果表明，较弱的磁暴使得相对论电子高通量区域更接近同步轨道，此外，哨声波加速很可能在2010年4月地球同步轨道相对论电子通量异常增强事件中起到重要作用．磁暴强度与种子电子的注入深度密切相关，表现为Dst指数曲线的形态与能量为30-100keV的电子高通量区域的下边缘高度吻合．能量为30-100keV电子的注入深度影响了能量大于300keV的电子出现的磁层区域
Handbook of relativistic quantum chemistry
Liu, Wenjian (ed.) [Peking Univ., Beijing (China). Center for Computational Science and Engineering
2017-03-01
This handbook focuses on the foundations of relativistic quantum mechanics and addresses a number of fundamental issues never covered before in a book. For instance: How can many-body theory be combined with quantum electrodynamics? How can quantum electrodynamics be interfaced with relativistic quantum chemistry? What is the most appropriate relativistic many-electron Hamiltonian? How can we achieve relativistic explicit correlation? How can we formulate relativistic properties? - just to name a few. Since relativistic quantum chemistry is an integral component of computational chemistry, this handbook also supplements the ''Handbook of Computational Chemistry''. Generally speaking, it aims to establish the 'big picture' of relativistic molecular quantum mechanics as the union of quantum electrodynamics and relativistic quantum chemistry. Accordingly, it provides an accessible introduction for readers new to the field, presents advanced methodologies for experts, and discusses possible future perspectives, helping readers understand when/how to apply/develop the methodologies.
THE ELECTRONIC COURSE OF HEAT AND MASS TRANSFER
Alexander P. Solodov
2013-01-01
Full Text Available The Electronic course of heat and mass transfer in power engineering is presented containing the full Electronic book as the structured hypertext document, the full set of Mathcad-documents with the whole set of educative computer models of heat and mass transfer, the computer labs, and selected educational presentations.
Bruce, Adam L
2015-01-01
We show the traditional rocket problem, where the ejecta velocity is assumed constant, can be reduced to an integral quadrature of which the completely non-relativistic equation of Tsiolkovsky, as well as the fully relativistic equation derived by Ackeret, are limiting cases. By expanding this quadrature in series, it is shown explicitly how relativistic corrections to the mass ratio equation as the rocket transitions from the Newtonian to the relativistic regime can be represented as products of exponential functions of the rocket velocity, ejecta velocity, and the speed of light. We find that even low order correction products approximate the traditional relativistic equation to a high accuracy in flight regimes up to $0.5c$ while retaining a clear distinction between the non-relativistic base-case and relativistic corrections. We furthermore use the results developed to consider the case where the rocket is not moving relativistically but the ejecta stream is, and where the ejecta stream is massless.
Krause, L. Habsh; Gilchrist, B. E.; Nishikawa, Ken-Ichi
2013-01-01
Relativisitic electron precipitation (REP) events occur when beams or bunches of relativistic electrons of magnetospheric origin enter the Earth's atmosphere, typically at auroral latitudes. REP events are associated with a variety of space weather effects, including production of transitional and bremsstrahlung radiation, catalytic depletion of stratospheric ozone, and scintillation of transionospheric radio waves. This study examines the intensities of x-rays produced at airliner, manned balloon, and space reuseable launch vehicles (sRLVs). The monoenergetic beam is modeled in cylindrical symetry using the paraxial ray equation. Bremsstrahlung photon production is calculated using the traditional Sauter-Elwert cross-section, providing x-ray emission spectra differential in energy and angle. Attenuation is computed for a plane-stratified standard atmosphere, and the loss processes include photoionization, Rayleigh and Compton scattering, electron-positron pair production, and photonuclear interaction. Peak altitudes of electron energy deposition and bremsstrahlung x-ray production were calculated for beams of energies from 1 MeV through 100 MeV. The altitude peak of bremsstrahlung deposition was consistently and significantly lower that that of the electron deposition due to the longer mean free paths of x-rays compared to electrons within the atmosphere. For example, for a nadir-directed monoenergetic 5 MeV beam, the peak deposition altitude was calculated to be 42 km, but the resulting bremsstrahlung deposition peaked at 25 km. This has implications for crew and passenger safety, especially with the growth of the space tourism industry. A survey of results covering the 1-100 MeV spectrum for the three altitude ranges of interest will be presented.
Skripnikov, L V
2016-01-01
A precise theoretical study of the electronic structure of heavy atom diatomic molecules is of key importance to interpret the experiments in the search for violation of time-reversal (T) and spatial-parity (P) symmetries of fundamental interactions it terms of the electron electric dipole moment, eEDM, and dimensionless constant, $k_{T,P}$, characterizing the strength of the T,P-odd pseudoscalar$-$scalar electron$-$nucleus neutral current interaction. ACME collaboration has recently obtained and improved limits on these quantities using a beam of ThO molecules in the $H^3\\Delta_1$ state [Science 343, 269 (2014)]. We apply the combined direct 4-component and two-step relativistic pseudopotential/restoration approaches to a benchmark calculation of the effective electric field, Eeff, parameter of the T,P-odd pseudoscalar$-$scalar interaction, $W_{T,P}$, and HFS constant in $^3\\Delta_1$ state of the ThO molecule. The first two parameters are required to interpret the experimental data in terms of the eEDM and $...
Decker, J.; Peysson, Y
2004-12-01
A new original code for solving the 3-D relativistic and bounce-averaged electron drift kinetic equation is presented. It designed for the current drive problem in tokamak with an arbitrary magnetic equilibrium. This tool allows self-consistent calculations of the bootstrap current in presence of other external current sources. RF current drive for arbitrary type of waves may be used. Several moments of the electron distribution function are determined, like the exact and effective fractions of trapped electrons, the plasma current, absorbed RF power, runaway and magnetic ripple loss rates and non-thermal Bremsstrahlung. Advanced numerical techniques have been used to make it the first fully implicit (reverse time) 3-D solver, particularly well designed for implementation in a chain of code for realistic current drive calculations in high {beta}{sub p} plasmas. All the details of the physics background and the numerical scheme are presented, as well a some examples to illustrate main code capabilities. Several important numerical points are addressed concerning code stability and potential numerical and physical limitations. (authors)
Observation of coherent transition radiation using relativistic pico second electron pulse
Jones, C.R.; Kosai, H.; Dutt, J.M. [North Carolina Central Univ., Durham, NC (United States)
1995-12-31
When an electron beams passes through boundaries of two different media with different dielectric constants, it generates radiation. The radiation emitted by the prebunched electron beam becomes coherent if the size of the bunch is smaller than the wavelength. Therefore, transition radiation can be considered as a possible broad band radiation source as well as a probe to the pico second and sub picosecond electron beam profiles. Using 1.2 MeV, 200 mA, macropulse electron beam, transition radiation was generated. The electron gun consists of 2.856 GHz Klystron, thermionic cathode. The emitted electron beam was bunched by passing through an alpha magnet. As a result of the combination, a pico second pulse (1.2 MeV, up to 80 A micropulse) was obtained. Experimental results, comparisons with the theory, and simulated electron beam profiles will be presented.
Recent progresses in relativistic beam-plasma instability theory
A. Bret
2010-11-01
Full Text Available Beam-plasma instabilities are a key physical process in many astrophysical phenomena. Within the fireball model of Gamma ray bursts, they first mediate a relativistic collisionless shock before they produce upstream the turbulence needed for the Fermi acceleration process. While non-relativistic systems are usually governed by flow-aligned unstable modes, relativistic ones are likely to be dominated by normally or even obliquely propagating waves. After reviewing the basis of the theory, results related to the relativistic kinetic regime of the poorly-known oblique unstable modes will be presented. Relevant systems besides the well-known electron beam-plasma interaction are presented, and it is shown how the concept of modes hierarchy yields a criterion to assess the proton to electron mass ratio in Particle in cell simulations.
刘铁路; 王云良; 路彦珍
2015-01-01
The nonlinear propagation of quantum ion acoustic wave (QIAW) is investigated in a four-component plasma com-posed of warm classical positive ions and negative ions, as well as inertialess relativistically degenerate electrons and positrons. A nonlinear Schr ¨odinger equation is derived by using the reductive perturbation method, which governs the dynamics of QIAW packets. The modulation instability analysis of QIAWs is considered based on the typical parameters of the white dwarf. The results exhibit that both in weakly relativistic limit and in ultrarelativistic limit, the modulational instability regions are sensitively dependent on the ratios of temperature and number density of negative ions to those of positive ions respectively, and on relativistically degenerate effect as well.
Applying Relativistic Reconnection to Blazar Jets
Nalewajko, Krzysztof
2016-01-01
Rapid and luminous flares of non-thermal radiation observed in blazars require an efficient mechanism of energy dissipation and particle acceleration in relativistic active galactic nuclei (AGN) jets. Particle acceleration in relativistic magnetic reconnection is being actively studied by kinetic numerical simulations. Relativistic reconnection produces hard power-law electron energy distributions N(gamma) = N_0 gamma^(-p) exp(-gamma/gamma_max) with index p -> 1 and exponential cut-off Lorentz factor gamma_max ~ sigma in the limit of magnetization sigma = B^2/(4 pi w) >> 1 (where w is the relativistic enthalpy density). Reconnection in electron-proton plasma can additionally boost gamma_max by the mass ratio m_p/m_e. Hence, in order to accelerate particles to gamma_max ~ 10^6 in the case of BL Lacs, reconnection should proceed in plasma of very high magnetization sigma_max >~ 10^3. On the other hand, moderate mean jet magnetization values are required for magnetic bulk acceleration of relativistic jets, sigma...
Relativistic mixtures of charged and uncharged particles
Kremer, Gilberto M. [Departamento de Física, Universidade Federal do Paraná, Curitiba (Brazil)
2014-01-14
Mixtures of relativistic gases within the framework of Boltzmann equation are analyzed. Three systems are considered. The first one refers to a mixture of uncharged particles by using Grad’s moment method, where the relativistic mixture is characterized by the moments of the distribution functions: particle four-flows, energy-momentum tensors, and third-order moment tensors. In the second Fick’s law for a mixture of relativistic gases of non-disparate rest masses in a Schwarzschild metric are derived from an extension of Marle and McCormack model equations applied to a relativistic truncated Grad’s distribution function, where it is shown the dependence of the diffusion coefficient on the gravitational potential. The third one consists in the derivation of the relativistic laws of Ohm and Fourier for a binary mixtures of electrons with protons and electrons with photons subjected to external electromagnetic fields and in presence of gravitational fields by using the Anderson and Witting model of the Boltzmann equation.
Murphy, Gareth C.; Dieckmann, Mark E.; BRET, ANTOINE; Drury, Luke O'C.
2010-01-01
The prompt emissions of gamma-ray bursts are seeded by radiating ultrarelativistic electrons. Internal shocks propagating through a jet launched by a stellar implosion, are expected to amplify the magnetic field & accelerate electrons. We explore the effects of density asymmetry & a quasi-parallel magnetic field on the collision of plasma clouds. A 2D relativistic PIC simulation models the collision of two plasma clouds, in the presence of a quasi-parallel magnetic field. The cloud density ra...