Appendix - Some spectroscopic observations of the interaction between a plasma wind and a dipole magnetic field
Spectroscopic studies on seeded plasma interaction with magnetic dipole field
PLASMA-ELECTROMAGNETIC INTERACTION↗
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Photoproduction of Mesons off Light Nuclei
During the last few years, a series of experiments has been done at the ELSA accelerator in Bonn with the Crystal Barrel/TAPS setup and at the MAMI accelerator in Mainz with the Crystal Ball/TAPS setup. Photoproduction of light mesons off the deuteron and {sup 3}He-nuclei has been studied in detail. We will report some of the most interesting results.A completely unexpected finding, is the pronounced structure in the excitation function of the {gamma}n {yields} n{eta} reaction around 1 GeV, which has no counterpart for the proton. Recent measurements at GRAAL, Sendai, ELSA [1] and MAMI estimate it's width below 50 MeV, which would be extremely narrow for a nucleon resonance at this excitation energy. In the experiment with the {sup 3}He target, special attention was given to the threshold behavior of the {gamma}He{sup 3} reactions in view of possible indications for the formation of (quasi-)bound {eta}-nucleus states, so-called {eta}-mesic nuclei. A very strong threshold enhancement of coherent {eta}-photoproduction off {sup 3}He was found. In a new experiment, this reaction was measured with much better statistical accuracy compared to an earlier experiment at MAMI-B using the TAPS detector [2].
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
Near-field heat transfer between gold nanoparticle arrays
The radiative heat transfer between gold nanoparticle layers is presented using the coupled dipole method. Gold nanoparticles are modelled as effective electric and magnetic dipoles interacting via electromagnetic fluctuations. The effect of higher-order multipoles is implemented in the expression of electric polarizability to calculate the interactions at short distances. Our findings show that the near-field radiation reduces as the radius of the nanoparticles is increased. Also, the magnetic dipole contribution to the heat exchange becomes more important for larger particles. When one layer is displayed in parallel with respect to the other layer, the near-field heat transfer exhibits oscillatory-like features due to the influence of the individual nanostructures. Further details about the effect of the nanoparticles size are also discussed.
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
Theoretical highlights on neutrino-nucleus interactions: current challenges
The present theoretical status of neutrino interactions in the few-GeV region is reviewed. Quasielastic scattering, pion production and their importance for neutrino oscillation studies are discussed, making emphasis on the open questions that arise in the comparison with new experimental data.
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
A measurement of double spin asymmetry A{sub LT} in semi-inclusive pion electroproduction on a transversely polarized {sup 3}He target
The double spin asymmetry A{sub LT} for {sup 3}He was measured for the first time at Jefferson Lab Hall A in the semi-inclusive {sup 3}He{up_arrow}({sup {yields}e},{pi}{sup +/-}X reactions, using a 6 GeV polarized electron beam on a transversely polarized {sup 3}He target. The produced charged pions were detected in coincidence with the scattered electrons by the high-resolution spectrometer and the BigBite spectrometer, respectively. The kinematic coverage was focused on the valence quark region, x {approx} 0.13-0.41, Q{sup 2}{approx} 1.31-3.10 (GeV/c){sup 2}. When combined with the world data, this new data will provide constraints on the g{sub 1T}{sup q} distribution functions, which describe the longitudinal polarization of quarks in a transversely polarized nucleon. The status of the current analysis and the preliminary results are presented.
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
Regge-plus-resonance predictions for neutral-kaon photoproduction from the deuteron
We present a Regge-inspired effective-Lagrangian framework for neutral-kaon photo-production from the deuteron. Quasi-free kaon production is investigated using the Regge-plus-resonance elementary operator within the relativistic plane-wave impulse approximation. The Regge-plus-resonance model was developed to describe photoinduced and electroinduced charged-kaon production off protons. We show how this elementary operator can be transformed to account for the production of neutral kaons from both protons and neutrons. Our results compare favourably to the sole {sup 2}H({gamma},K{sup 0})YN dataset published to date.
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
Hyperon forward spin polarizabilty {gamma}{sub 0}
We present the results of a systematic leading-order calculation of hyperon Compton scattering and extract the forward spin polarizability--{gamma}{sub 0}--of hyperons within the framework of SU(3) heavy baryon chiral perturbation theory (HBChPT). The results obtained for {gamma}{sub 0} in the case of nucleons agree with that of the known results of SU(2) HBChPT when kaon loops are not considered.
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
Bragg interactions in periodic media
The interaction of electromagnetic waves of wavelength lambda with periodic structures of spatial period lambda are studied. The emphasis of the work is on Bragg interactions where lambda approximately equal to 2 lambda/N and the Bragg order N takes on the values 1, 2,.... An extended coupled waves (ECW) theory is developed for the case N greater or equal to 2 and the results of the theory are found to compare favorably with the exact results of Floquet theory. Numerous numerical results are displayed as Brillouin diagrams for the first few Bragg orders. Moreover, explicit expressions for coupling coefficients, bandgap shifts and bandgap widths are derived for singly periodic media. Particular note is taken of phase speeding effects.
Jaggard, D. L.↗
Kinetic theory of the electron bounce instability in two dimensional current sheets—Full electromagnetic treatment
In the general context of understanding the possible destabilization of a current sheet with applications to magnetospheric substorms or solar flares, a kinetic model is proposed for studying the resonant interaction between electromagnetic fluctuations and trapped bouncing electrons in a 2D current sheet. Tur et al. [A. Tur et al., Phys. Plasmas 17, 102905 (2010)] and Fruit et al. [G. Fruit et al., Phys. Plasmas 20, 022113 (2013)] already used this model to investigate the possibilities of electrostatic instabilities. Here, the model is completed for full electromagnetic perturbations. Starting with a modified Harris sheet as equilibrium state, the linearized gyrokinetic Vlasov equation is solved for electromagnetic fluctuations with period of the order of the electron bounce period. The particle motion is restricted to its first Fourier component along the magnetic field and this allows the complete time integration of the non local perturbed distribution functions. The dispersion relation for electromagnetic modes is finally obtained through the quasineutrality condition and the Ampere's law for the current density. It is found that for mildly strechted current, undamped modes oscillate at typical electron bounce frequency with wavelength of the order of the plasma sheet half thickness. As the stretching of the plasma sheet becomes more intense, the frequency of these normal modes decreases and beyond a certain threshold in ε = B{sub z}/B{sub lobes}, the mode becomes explosive with typical growth rate of a few tens of seconds. The free energy contained in the bouncing motion of the electrons may trigger an electromagnetic instability able to disrupt the cross-tail current in a few seconds. This new instability–electromagnetic electron-bounce instability–may explain fast and global scale destabilization of current sheets as required to describe substorm phenomena.
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
Transition from thermal to turbulent equilibrium with a resulting electromagnetic spectrum
A recent paper [Ziebell et al., Phys. Plasmas 21, 010701 (2014)] discusses a new type of radiation emission process for plasmas in a state of quasi-equilibrium between the particles and enhanced Langmuir turbulence. Such a system may be an example of the so-called “turbulent quasi-equilibrium.” In the present paper, it is shown on the basis of electromagnetic weak turbulence theory that an initial thermal equilibrium state (i.e., only electrostatic fluctuations and Maxwellian particle distributions) transitions toward the turbulent quasi-equilibrium state with enhanced electromagnetic radiation spectrum, thus demonstrating that the turbulent quasi-equilibrium discussed in the above paper correctly describes the weakly turbulent plasma dynamically interacting with electromagnetic fluctuations, while maintaining a dynamical steady-state in the average sense.
70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
Drekar v.2.0
Drekar is an application code that solves partial differential equations for fluids that can be optionally coupled to electromagnetics. Drekar solves low-mach compressible and incompressible computational fluid dynamics (CFD), compressible and incompressible resistive magnetohydrodynamics (MHD), and multiple species plasmas interacting with electromagnetic fields. Drekar discretization technology includes continuous and discontinuous finite element formulations, stabilized finite element formulations, mixed integration finite element bases (nodal, edge, face, volume) and an initial arbitrary Lagrangian Eulerian (ALE) capability. Drekar contains the implementation of the discretized physics and leverages the open source Trilinos project for both parallel solver capabilities and general finite element discretization tools. The code will be released open source under a BSD license. The code is used for fundamental research for simulation of fluids and plasmas on high performance computing environments.
Seefeldt, Ben↗
Coherent {pi}{sup 0}-photoproduction on the deuteron including polarization observables
Coherent {pi}{sup 0}-photoproduction on the deuteron including polarization effects in the energy region from {pi}-threshold up to 1 GeV is studied using an enhanced elementary pion photo-production operator on the free nucleon and a realistic NN potential model for the deuteron wave function. Results for double polarization observables are predicted for which the sensitivity to various models for the elementary pion photoproduction amplitude is investigated. We find considerable dependence of the results on the elementary amplitude. In addition, results for differential cross section are predicted and compared with the experimental data from TAPS and a satisfactory agreement was found.
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
Differential cross sections and spin density matrix elements for {gamma}p {yields} {phi}p from CLAS
Preliminary differential cross-sections and the {rho}{sub MM'}{sup 0} spin density matrix elements (SDME) for the reaction {gamma}{rho} {yields} {phi}p for both charged-({phi} {yields} K{sup +}K-) and neutral-mode ({phi} {yields} K{sub L}{sup 0}K{sub S}{sup 0}) topologies obtained from CLAS are presented. Our kinematic coverage is from near production threshold ({radical}(s){approx}1.97 GeV) to ({radical}(s) 2.84 GeV), with a wide coverage in the production angle. As seen in previous LEPS results, the differential cross-sections show a localized 'bump' between ({radical}(s){approx}2 and 2.2 GeV that is not expected from a simple Pomeron exchange picture. Comparisons between the charged- and neutral-mode results and possible effects from the K{sup +}{Lambda}(1520) channel are discussed. Our SDME results confirm the well-known deviations from t-channel helicity conservation (TCHC) for Pomeron exchange, but s-channel helicity conservation (SCHC) is also seen to be broken.
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
A resonance interpretation for the nonmonotonic behavior of the {phi} photoproduction cross section near threshold
We study whether the nonmonotonic behavior found in the differential cross section of the {phi}-meson photoproduction near threshold can be described by a resonance. The resonant contribution is evaluated by using an effective Lagrangian approach. We find that, with the assumption of a J{sup P} 3/2{sup -} resonance with mass of 2.10{+-}0.03 GeV and width of 0.465{+-}0.141 GeV, LEPS data can indeed be well described. The ratio of the helicity amplitudes A{sub 1/2}/A{sub 3/2} calculated from the resulting coupling constants differs in sign from that of the known D{sub 13}(2080). We further find that the addition of this postulated resonance can substantially improve the agreement between the existing theoretical predictions and the recent {omega} photoproduction data if a large value of the OZI evading parameter xOZI = 12 is assumed for the resonance.
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
{Lambda}K*{Lambda}(1116) photoproduction and nucleon resonances
In this presentation, we report our recent studies on the {Lambda}K*{Lambda}(1116) photoproduction off the proton target, using the tree-level Born approximation, via the effective Lagrangian approach. In addition, we include the nine (three- or four-star confirmed) nucleon resonances below the threshold {radical}(s{sub th}){approx_equal}2008 MeV, to interpret the discrepancy between the experiment and previous theoretical studies, in the vicinity of the threshold region. From the numerical studies, we observe that the S{sub 11}(1535) and S11(1650) play an important role for the cross-section enhancement near the {radical}(s{sub th}). It also turns out that, in order to reproduce the data, we have the vector coupling constants gK*S{sub 11}(1535){Lambda} = (7.0{approx}9.0) and gK*S{sub 11}(1650){Lambda} (5.0{approx}6.0).
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
Confined states in photonic-magnonic crystals with complex unit cell
We have investigated multifunctional periodic structures in which electromagnetic waves and spin waves can be confined in the same areas. Such simultaneous localization of both sorts of excitations can potentially enhance the interaction between electromagnetic waves and spin waves. The system we considered has a form of one dimensional photonic-magnonic crystal with two types of magnetic layers (thicker and thinner ones) separated by sections of the dielectric photonic crystals. We focused on the electromagnetic defect modes localized in the magnetic layers (areas where spin waves can be excited) and decaying in the sections of conventional (nonmagnetic) photonic crystals. We showed how the change of relative thickness of two types of the magnetic layers can influence on the spectrum of spin waves and electromagnetic defect modes, both localized in magnetic parts of the system.
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
High-energy photon-hadron scattering in holographic QCD
This article provides an in-depth look at hadron high-energy scattering by using gravity dual descriptions of strongly coupled gauge theories. Just like deeply inelastic scattering (DIS) and deeply virtual Compton scattering (DVCS) serve as clean experimental probes into nonperturbative internal structure of hadrons, elastic scattering amplitude of a hadron and a (virtual) photon in gravity dual can be exploited as a theoretical probe. Since the scattering amplitude at sufficiently high energy (small Bjorken x) is dominated by parton contributions (=Pomeron contributions) even in strong coupling regime, there is a chance to learn a lesson for generalized parton distribution (GPD) by using gravity dual models. We begin with refining derivation of the Brower-Polchinski-Strassler-Tan (BPST) Pomeron kernel in gravity dual, paying particular attention to the role played by the complex spin variable j. The BPST Pomeron on warped spacetime consists of a Kaluza-Klein tower of 4D Pomerons with nonlinear trajectories, and we clarify the relation between Pomeron couplings and the Pomeron form factor. We emphasize that the saddle-point value j* of the scattering amplitude in the complex j-plane representation is a very important concept in understanding qualitative behavior of the scattering amplitude. The total Pomeron contribution to the scattering is decomposed into the saddle-point contribution and at most a finite number of pole contributions, and when the pole contributions are absent (which we call saddle-point phase), kinematical variable (q,x,t)-dependence of ln(1/q) evolution and ln(1/x) evolution parameters {gamma}{sub eff} and {lambda}{sub eff} in DIS and t-slope parameter B of DVCS in HERA experiment are all reproduced qualitatively in gravity dual. All of these observations shed a new light on modeling of GPD. Straightforward application of those results to other hadron high-energy scattering is also discussed.
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
An experimental study of gyro interaction in the ionosphere, at oblique incidence.
Gyro disturbing wave interaction with obliquely incident wanted wave in nighttime lower E region
E LAYER↗