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In this work, the excitation problem of bulk-surface helicons by a point magnetic dipole moving in a vacuum parallel to the element of magnetized solid-state plasma cylinder is theoretically studied. The external magnetic field is directed parallel to the cylinder axis. The problem is solved in the magnetostatic approximation. It is shown that hybrid modes of the magnetic type with large values of the azimuthal mode index and one field variation along the radius are most efficiently excited at nonrelativistic velocities of magnetic dipole.

Conservation of magnetic flux is associated with regions of the powerful magnetic fields (B ∽ 1013 G) near neutron stars' surface. The vector potential generated by moving electric charge Q is uniformly distributed within a Neutron star's surface (radius R). The evolution of the magnetic field of isolated neutron stars is studied and based on magnetic flux conservation; the multipolar magnetic fields for (l = 1; l = 2; l = 3; l = 4) have calculated. We developed the field line equations and simulated the magnetic field line geometry for the interaction between neutron stars’ dipole–multipolar magnetic fields using the MATLAB software program.

The magnetic dipole moments of the ${Z}_{c}(4020{)}^{+}$, ${Z}_{c}(4200{)}^{+}$, ${Z}_{cs}(4000{)}^{+}$ and ${Z}_{cs}(4220{)}^{+}$ states are extracted in the framework of the light-cone QCD sum rules. In the calculations, we use the hadronic molecular form of interpolating currents and photon distribution amplitudes to get the magnetic dipole moments of the ${Z}_{c}(4020{)}^{+}$, ${Z}_{c}(4200{)}^{+}$, ${Z}_{cs}(4000{)}^{+}$ and ${Z}_{cs}(4220{)}^{+}$ tetraquark states. The magnetic dipole moments are obtained as ${\ensuremath{\mu}}_{{Z}_{c}}=0.6{6}_{\ensuremath{-}0.25}^{+0.27}$, ${\ensuremath{\mu}}_{{Z}_{c}^{1}}=1.0{3}_{\ensuremath{-}0.29}^{+0.32}$, ${\ensuremath{\mu}}_{{Z}_{cs}}=0.7{3}_{\ensuremath{-}0.26}^{+0.28}$ and ${\ensuremath{\mu}}_{{Z}_{cs}^{1}}=0.7{7}_{\ensuremath{-}0.25}^{+0.27}$ for the ${Z}_{c}(4020{)}^{+}$, ${Z}_{c}(4200{)}^{+}$, ${Z}_{cs}(4000{)}^{+}$ and ${Z}_{cs}(4220{)}^{+}$ states, respectively. We observe that the results obtained for the ${Z}_{c}(4020{)}^{+}$, ${Z}_{c}(4200{)}^{+}$, ${Z}_{cs}(4000{)}^{+}$ and ${Z}_{cs}(4220{)}^{+}$ states are large enough to be measured experimentally. As a by product, we predict the magnetic dipole moments of the neutral ${Z}_{cs}(4000)$ and ${Z}_{cs}(4220)$ states. The results presented here can serve to be helpful knowledge in experimental as well as theoretical studies of the properties of hidden-charm tetraquark states with and without strangeness.

The gamma-decay of resonance-like structures observed in the reaction of the radiative capture of protons by 22Ne, 26Mg, 30Si, 34,36S, and 38Ar nuclei in the 7–12 MeV region of excitation energies is studied. The excitation functions of this reaction are measured. The resonance strengths of states in energy range Ep = 1.0–3.0 MeV of accelerated protons are determined. The discrete distributions of magnetic dipole γ-transitions between the ground and excited states for sd-shell nuclei are of a resonance nature. A magnetic dipole resonance is identified for the ground and excited states in the above nuclei. The position of the magnetic dipole resonance on the excited states coincides with the one predicted by the Brink–Axel hypothesis for nuclei at the beginning of a subshell.

The electric dipole (ED) and magnetic dipole (MD) resonances in a slab of dielectric nanostructures induced by oblique light incidence were analyzed in terms of guided-mode wave theory for transverse electric (TE) and transverse magnetic (TM) polarization. Owing to the symmetry breaking in TE and TM polarizations at oblique incidences of light, the resonance modes produced different features, which were analyzed with comprehensive studies of energy fluxes associated with the resonance modes. The MD resonances are excited by the guided-mode wave with an energy flux in the opposite direction in the incident plane for TM polarization and excited by two guided-mode waves with energy fluxes orthogonal to the incident plane for TE polarized light. Meanwhile, the ED resonances are excited by the guided-mode waves with energy fluxes in both directions, incident plane, and out of the incident plane for both TE and TM polarizations. The proposed analyses provide clear explanations of the stability or vanishing of resonance modes, with variations in the inter-distance between nanostructures near the Rayleigh anomaly condition, which were verified by the experimental measurements performed with 2D arrays of Si nanostructures for various incident angles with TE and TM polarizations.

A microscopic model analysis of the magnetic dipole (M1) properties of Pu-239 nucleus, which is a fissile material not only used in nuclear weapons but also used in some nuclear reactors as a source of energy, has been performed. The microscopic formalism used in the study is based on the Quasiparticle Phonon Nuclear Model (QPNM) and includes an axially symmetric Woods-Saxon potential as a mean field, a spin-spin residual interaction as well as the symmetry-restoring forces for the rotational invariance of the Hamiltonian. The investigations have been carried out in two steps. Firstly, the theoretical value of the ground-state magnetic moment and quenching spin gyromagnetic factor have been determined and it has been found that the predicted magnetic moment show a good agreement with the experimental data. Secondly, the calculations of M1 transitions from ground- to excited-states have been carried out in the energy range 2-4 MeV. A satisfactorily good agreement is obtained from the comparison of the theoretical results with the experimental data for 2-2.5 MeV. (C) 2019 Elsevier B.V. All rights reserved.

Energies, weighted oscillator strengths (gf), line strengths (S) and radiative rates (A) for allowed and forbidden transitions are presented for 2s2p62S1/2 − 2s22p52P1/2, 2P3/2 and 2s22p52P1/2 − 2s22p52P3/2 transitions in fluorine-like Ca XII (Z = 20), Ti XIV (Z = 22), Cr XVI (Z = 24), Fe XVIII (Z = 26) and Ni XX (Z = 28) ions. Moreover, the allowed electric dipole (E1) and the forbidden electric quadrupole (E2), octupole (E3), magnetic dipole (M1) and quadrupole (M2) transition rates for some transitions are obtained. The 2s22p5–2s 2p6-type transitions of F-like ions are prominent in high-temperature plasmas and are useful for diagnostics. The present results are obtained from configuration interaction atomic structure calculations using the code SUPERSTRUCTURE (SS) which includes relativistic effects in Breit–Pauli approximation. The comparison of the present energies with the available observed energies displayed very good agreement (

A low-energy magnetic dipole $(M1)$ spin-scissors resonance (SSR) located just below the ordinary orbital scissors resonance (OSR) was recently predicted in deformed nuclei within the Wigner Function Moments (WFM) approach. We analyze this prediction using fully self-consistent Skyrme Quasiparticle Random Phase Approximation (QRPA) method. Skyrme forces SkM*, SVbas and SG2 are implemented to explore SSR and OSR in $^{160,162,164}$Dy and $^{232}$Th. Accuracy of the method is justified by a good description of M1 spin-flip giant resonance. The calculations show that isotopes $^{160,162,164}$Dy indeed have at 1.5-2.4 MeV (below OSR) $I^{\pi}K=1^+1$ states with a large $M1$ spin strength ($K$ is the projection of the total nuclear moment to the symmetry z-axis). These states are almost fully exhausted by $pp[411\uparrow, 411\downarrow]$ and $nn[521\uparrow, 521\downarrow]$ spin-flip configurations corresponding to $pp[2d_{3/2}, 2d_{5/2}]$ and $nn[2f_{5/2}, 2f_{7/2}]$ structures in the spherical limit. So the predicted SSR is actually reduced to low-orbital (l=2,3) spin-flip states. Following our analysis and in contradiction with WFM spin-scissors picture, deformation is not the principle origin of the low-energy spin $M1$ states but only a factor affecting their features. The spin and orbital strengths are generally mixed and exhibit the interference: weak destructive in SSR range and strong constructive in OSR range. In $^{232}$Th, the $M1$ spin strength is found very small. Two groups of $I^{\pi}=1^+$ states observed experimentally at 2.4-4 MeV in $^{160,162,164}$Dy and at 2-4 MeV in $^{232}$Th are mainly explained by fragmentation of the orbital strength. Distributions of nuclear currents in QRPA states partly correspond to the isovector orbital-scissors flow but not to spin-scissors one., Comment: 15 pages, 13 figures

Magnetic dipole (MD) spontaneous emission plays a vital role in the field of optical magnetism, which has been observed in trivalent lanthanide ions. In this case, the luminescence properties of the MD are largely affected by the crystal field symmetry at the embedding trivalent lanthanide ion site, but the correlation between the doping properties and the MD emission has not been fully understood. Here, we systematically investigate the doping properties of Eu in $\mathrm{Sr}M{\mathrm{O}}_{3}$ ($M=\mathrm{Ti},\mathrm{Zr},\mathrm{Hf}$) using first-principles calculations, in order to maximize the MD emission efficiency of the Eu-doped perovskites. By analyzing the formation energies under the accessible growth conditions, we determine the ideal conditions for Eu-doped perovskites that could maximize the MD emission. We also theoretically demonstrate the spin flipping emission mechanism of ${\mathrm{Eu}}^{3+}$. Our study thus provides a guideline for the design of highly efficient MD emission materials.

The recent detections of electric-quadrupole (E2) transitions in water vapor and magnetic-dipole (M1) transitions in carbon dioxide have opened a new field in molecular spectroscopy. While in their present status, the spectroscopic databases provide only electric-dipole (E1) transitions for polyatomic molecules (H$_2$O, CO$_2$, N$_2$O, CH$_4$, O$_3$…), the possible impact of weak E2 and M1 bands to the modeling of the Earth and planetary atmospheres has to be addressed. This is especially important in the case of carbon dioxide for which E2 and M1 bands may be located in spectral windows of weak E1 absorption. In the present work, a high sensitivity absorption spectrum of CO$_2$ is recorded by Optical-Feedback-Cavity Enhanced Absorption Spectroscopy (OFCEAS) in the 3.3 µm transparency window of carbon dioxide. The studied spectral interval corresponds to the region where M1 transitions of the $ν_{2}+ν_{3}$band of carbon dioxide were recently identified in the spectrum of the Martian atmosphere. Here, both M1 and E2 transitions of the $ν_{2}+ν_{3}$ band are detected by OFCEAS. Using recent ab initio calculations of the E2 spectrum of $^{12}$C$^{16}$O$_2$, intensity measurements of five M1 lines and three E2 lines allow us to disentangle the M1 and E2 contributions. Indeed, E2 intensity values (on the order of a few 10$^{–29}$ cm/molecule) are found in reasonable agreement with ab initio calculations while the intensity of the M1 lines (including an E2 contribution) agree very well with recent very long path measurements by Fourier Transform spectroscopy. We thus conclude that both E2 and M1 transitions should be systematically incorporated in the CO$_2$ line list provided by spectroscopic databases.

Magnetic dipole and electric quadrupole absorption in carbon dioxide are addressed in details. The selection rules for both processes are presented. The equations for the line intensities are given. In the case of the quadrupole absorption the Herman-Wallis functions are derived. The results of the present paper were used in the analysis of the carbon dioxide absorption band at 3.3 µm in the atmosphere of Mars (Trokhimovskiy A, Perevalov V, Korablev O, Fedorova A, Olsen KS, Bertaux JL, Patrakeev A, Shakun A, Montmessin F, Lefevre F, Lukashevskaya A. First observation of the magnetic dipole CO2 absorption band at 3.3 µm in the atmosphere of Mars by ExoMars Trace Gas Orbiter ACS instrument. A&A 639, A142 (2020)). The retrieved from the Martian atmosphere spectra vibrational transition magnetic dipole moment for the 01111–00001 (ν2+ν3) band of 12C16O2 M 01111 ← 000001 | Δ l 2 | = 1 = 0.96 μ N (where μN is nuclear magneton) is one order of magnitude larger than the gyromagnetic ratio in the case of the rotation-induced magnetic dipole moment.

Background: There is renewed interest in electric dipole strength distributions for a variety of reasons including the extraction of the dipole polarizability related to properties of the symmetry energy and a measure for the neutron skin thickness, understanding the structure of low-energy E1 strength in nuclei with neutron excess, and establishing the systematics of the isovector giant dipole resonance (IVGDR). Inelastic proton scattering at energies of a few hundred MeV and very forward angles including 0∘ has been established as a tool for the study of electric and magnetic dipole strength distributions in nuclei. Purpose: The present work aims at a systematic investigation of the electric and magnetic dipole strength distributions in the chain of stable even-mass tin isotopes. Methods: Inelastic proton scattering experiments were performed at the Research Center for Nuclear Physics, Osaka, with a 295-MeV beam covering laboratory angles 0∘–6∘ and excitation energies 6–22 MeV. Cross sections due to E1 and M1 excitations were extracted with a multipole decomposition analysis (MDA) and then converted to reduced transition probabilities with the “virtual photon method” for E1 and the “unit cross section method” for M1 excitations, respectively. Including a theory-aided correction for the high-excitation-energy region not covered experimentally, the electric dipole polarizability was determined from the E1 strength distributions. Results: Total photoabsorption cross sections derived from the E1 and M1 strength distributions show significant differences compared to those from previous (γ,xn) experiments in the energy region of the IVGDR. The widths of the IVGDR deduced from the present data with a Lorentz parametrization show an approximately constant value of about 4.5 MeV in contrast to the large variations between isotopes observed in previous work. The IVGDR centroid energies are in good correspondence to expectations from empirical systematics of their mass dependence. Furthermore, a study of the dependence of the IVGDR energies on bulk matter properties is presented. The E1 strengths below neutron threshold show fair agreement with results from (γ,γ′) experiments on Sn112,116,120,124 in the energy region between 6 and 7 MeV, where also isoscalar E1 strength was found for Sn124. At higher excitation energies, large differences are observed, pointing to a different nature of the excited states with small ground-state branching ratios. The isovector spin-M1 strengths exhibit a broad distribution between 6 and 12 MeV in all studied nuclei. Conclusions: The present results contribute to the solution of a variety of nuclear structure problems including the systematics of the energy and width of the IVGDR, the structure of low-energy E1 strength in nuclei, new constraints to energy density functionals (EDFs) aiming at a systematic description of the dipole polarizability across the nuclear chart, from which properties of the symmetry energy can be derived, and the systematics of the isovector spin-M1 strength in heavy nuclei.

The CO2-dominated atmosphere of Mars is an ideal natural laboratory to study the spectroscopy of this gas. The Atmospheric Chemistry Suite (ACS) package onboard the ExoMars 2016 Trace Gas Orbiter (TGO) sounds the atmosphere in solar occultation, allowing, in case of a very clear atmosphere, reaching an optical path of 300-400 km at an effective pressure of a few millibars. During the first year of ACS observations, the focus of attention was kept on the spectral range covering the fundamental methane absorption band, 2900-3300 cm–1. No methane was detected, while a further improvement of the data processing led to the identification of weak periodic absorption lines, missing from spectroscopic databases. The observed frequencies of the lines match theoretically computed positions of the Q, P and R branches of the magnetic dipole 01111-00001 absorption band of the main CO2 isotopologue, never measured or computed before. We will report the first observational evidence of a magnetic dipole CO2 absorption. The data analysis was supported by RSF (project No. 20-42-09035).

This work reports new, accurate nuclear magnetic dipole moments for NMR-active transition metal nuclei where the long-standing systematic error due to obsolete diamagnetic correction has been eliminated by ab initio calculations of absolute NMR shielding constants. The error of the diamagnetic correction reaches ≈ −14 000 ppm for rhenium, which results in magnetic dipole moment corrections of about −3 × 10−2μN for the 185Re and 187Re nuclei. Such extreme values are one to two orders of magnitude larger than the corrections reported in the literature so far. These findings may help to resolve discrepancies in hyperfine splitting experiments involving rhenium ions. To obtain the corrected transition metal nuclear magnetic dipole moments, NMR shielding constants for a series of transition metal complexes defined as NMR standards [Harris et al., Pure Appl. Chem., 2001, 73, 1795] were calculated using the non-relativistic coupled cluster method and four-component relativistic density functional theory. To reproduce the experimental conditions of the NMR standards, the solvent effects were incorporated by explicit and implicit solvent models.

The evolution of electromagnetic transitions along isotope chains is of particular importance for the nuclear structure and dynamics, as well as for the r-process nucleosynthesis. Recent measurement of inelastic proton scattering on even-even $^{112\ensuremath{-}124}\mathrm{Sn}$ isotopes provides novel insight into the isotopic dependence of E1 and M1 strength distributions. We investigate M1 transitions in even-even $^{100\ensuremath{-}140}\mathrm{Sn}$ isotopes from a theoretical perspective, based on the relativistic nuclear energy density functional. The M1 transition strength distribution is characterized by an interplay between single- and double-peak structures that can be understood from the evolution of single-particle states, their occupations governed by the pairing correlations, and two-quasiparticle transitions involved. It is shown that the discrepancy between model calculations and experiments for the M1 transition strength is considerably more reduced than previously known, and the quenching of the $g$ factors for the free nucleons needed to reproduce the experimental data on M1 transition strength amounts ${g}_{\mathrm{eff}}/{g}_{\mathrm{free}}=0.80--0.93$. Because some of the M1 strength above the neutron threshold may be missing in the inelastic proton scattering measurement, further experimental studies are required to confirm if only small modifications of the bare $g$ factors are actually needed when applied in finite nuclei.

The creation of an electron space charge in a dipole magnetic trap and the subsequent injection of positrons has been experimentally demonstrated. Positrons (5eV) were magnetically guided from their source and injected into the trapping field generated by a permanent magnet (0.6T at the poles) using a cross field E $\times$ B drift, requiring tailored electrostatic and magnetic fields. The electron cloud is created by thermionic emission from a tungsten filament. The maximum space charge potential of the electron cloud reaches -42V, which is consistent with an average electron density of ($4 \pm 2$) $\times 10^{12}$ $\text{m}^{-3}$ and a Debye length of ($2 \pm 1$) $\text{cm}$. We demonstrate that the presence of this space potential does not hamper efficient positron injection. Understanding the effects of the negative space charge on the injection and confinement of positrons represents an important intermediate step towards the production of a confined electron-positron pair plasma.

Lossless injection of positrons into a magnetic dipole trap and their subsequent confinement have been demonstrated. Here, we investigate by numerical single-particle simulations how the radial distribution of positrons in the trap is affected by the measurement itself, the choice of injection parameters, the asymmetry of the electric potential, and by elastic collisions. The results are compared to experimental data. A comprehensive understanding of these effects is a milestone on the road to creating an electron–positron plasma in a trap with a levitating superconducting coil.

The magnetic dipole ( M 1) response of the 169 Tm nucleus is investigated from a theoretical point of view. The theoretical tool used in this study is the Rotational Invariant Quasiparticle Phonon Nuclear Model (RI-QPNM) which gives a possibility to eliminate spurious contributions in the M 1 spectrum. In the framework of this model, both the low-lying and high-lying parts of the M 1 excitation spectrum of 169 Tm are calculated. The result shows that the low-lying excitations have almost pure orbital character and can be interpreted as scissors mode, whereas the high-lying transitions can be read as spin-flip mode because of its spin nature. The reduced transition probability summed up in the energy range 2–4 MeV is found to be B ( M 1 ↑ ) = 3.040 μ N 2 which agrees with the available experimental data. The fragmentation of the low-energy M 1 strength is also well reproduced. This is also the first study in which both the low-lying and high-lying M 1 spectrum of the 169 Tm nucleus is theoretically investigated.

The fluorescence lifetime for magnetic dipole 5D0→7F1 transition in yttrium aluminum garnet doped with Eu3+ (YAG:Eu3+) crystal was studied under the pressure of up to 10.4 GPa at room temperature. ...

The dipole strength of the $N=28$ closed-shell nuclide $^{54}\mathrm{Fe}$ was studied in photon-scattering experiments using bremsstrahlung produced with electron beams of kinetic energies of 7.5 and 13.9 MeV at the $\ensuremath{\gamma}\mathrm{ELBE}$ facility as well as using quasimonoenergetic and linearly polarized photon beams of 26 different energies within the range from 5.5 to 11.4 MeV at the $\mathrm{HI}\ensuremath{\gamma}\mathrm{S}$ facility. About 100 $J=1$ states were newly identified, out of them 19 with ${1}^{+}$ and 30 with ${1}^{\ensuremath{-}}$ assignments. The quasicontinuum of unresolved transitions was included in the analysis of the spectra and the intensities of branching transitions were estimated on the basis of simulations of statistical $\ensuremath{\gamma}$-ray cascades. As a result, the photoabsorption cross section up to the neutron-separation energy was determined and compared with predictions of the statistical reaction model. The experimental $M1$ strengths from resolved ${1}^{+}$ states are compared with results of large-scale shell-model calculations.

Low-lying dipole transitions in $^{207}\mathrm{Pb}$ were measured via nuclear photon scattering using a quasimonochromatic, linearly polarized photon beam. The spins and/or parities of the states observed in $^{207}\mathrm{Pb}$ were determined from the intensity asymmetry of resonantly scattered $\ensuremath{\gamma}$ rays with respect to the polarization plane of the incident photon beam. The electric ($E1$) and magnetic ($M1$) dipole strengths were obtained for excitation energies from 5.49 to 6.75 MeV. The present experimental results, combined with $(\ensuremath{\gamma},n)$ data from the literature, were used to investigate the $E1$ and $M1$ photoabsorption cross sections near the neutron separation energy by comparison with predictions from the particle-vibration coupling with the quasiparticle random-phase approximation model.

Metalens is a planar device for light focusing. In this work, we design and optimize c-Si nanosphere metalenses working on the magnetic dipole and quadrupole resonances of the c-Si nanoparticle. Resonant optical response of c-Si nanostructures is simulated by the multipole decomposition method along with the zero-order Born approximation. Limitations of this approach are investigated. The obtained results of optimization are verified by simulation via the T-matrix method.

The radiative transition probability is a fundamental property for optical transitions. Extensive research, theoretical and experimental, has been conducted to establish the relation between the photonic environment and electric dipole (ED) transition probabilities. Recent work shows that the nanocrystal (NC)-cavity model accurately describes the influence of the refractive index n on ED transition rates for emitters in NCs. For magnetic dipole (MD) transitions, theory predicts a simple n3 dependence. However, experimental evidence is sparse and difficult to obtain. Here we report Eu3+-(with distinct ED+MD transitions) and Gd3+-(MD transitions) doped β-NaYF4 NC model systems to probe the influence of n on ED and MD transition probabilities through luminescence lifetime and ED/MD intensity ratio measurements. The results provide strong experimental evidence for an n3 dependence of MD transition probabilities. This insight is important for understanding and controlling the variation of spectral distribution in emission spectra by photonic effects.

High-index dielectric nanostructures support inherently strong magnetic dipole (MD) resonances at optical frequencies with minimal dissipative absorptions. They are promising candidates for MD radiation enhancement. Previous investigations, however, show that the maximum magnetic field enhancement is confined inside the nanostructure and therefore inaccessible to nearby MD emitters, limiting the achievable emission enhancement. In this paper, we design a nano-doughnut-shaped silicon disk, i.e., a disk with an open hole through its center. This way, the maximum magnetic field intensity is exposed and can be leveraged to fully enhance MD radiations. On the basis of numerical calculations, a record high enhancement factor of the radiative decay rate up to 350 has been achieved with minimal nonradiative losses. We further demonstrate the importance of spectral and spatial overlap of the MD emitter with the MD resonance in the silicon nanodisk in order to maximize the MD radiations. Our study opens new possibi...

The low-lying magnetic dipole ( M 1) strength in deformed odd-mass 155 – 169 Ho nuclei is investigated using rotational invariant (RI-) Quasiparticle Phonon Nuclear Model (QPNM). The gross features and fragmentation of the scissors mode in 165 Ho is well reproduced by RI-QPNM calculations. The systematics of the low-energy M 1 excitation in Ho isotopic chain is discussed with respect to summed strength. Besides, the results for M 1 excitations in odd-mass Ho isotopes are compared with the systematics of the scissors mode in the neighbouring even–even nuclei. The obtained results generally match the systematic and trends typical for the scissors motion. In addition to the low-lying M 1 excitations, a M 1 giant resonance in the 7–15 MeV energy region is predicted for 155 – 169 Ho nuclei in the present study.

The problem of point injection of charged particles into a magnetic dipole field was considered. Analytical expressions were obtained by the Stormer method for regions of allowed pulses of charged particles at random points of a dipole field at a set position of the point source of particles. It was found that, for a fixed location of the studied point, there was a specific structure of the coordinate space in the form of a set of seven regions, where the injector location in each region corresponded to a definite form of an allowed pulse region at the studied point. It was shown that the allowed region boundaries in four of the mentioned regions were surfaces of conic section revolution.

As a magnetic confinement configuration for electron-positron pair-plasmas, the APEX collaboration [T. S. Pedersen et al., New J. Phys. 14, 035010 (2012)] plans to construct a compact levitated dipole experiment with a high-temperature superconducting coil. In order to realize stable levitation of the dipole field coil, a simple feedback-controlled levitation system was constructed with conventional analog circuits. We report the properties of a prototype levitation system using a permanent magnet and compare its behavior to predictions from a stability analysis. We also present a practical review needed for the construction of a compact levitated dipole trap system based on the work of Morikawa et al. [Teion Kogaku, J. Cryo. Soc. Jpn. 39, 209 (2004)]. Numerical orbit analysis suggests improved confinement properties of charged particles in a dipole field trap by replacing the permanent magnet with a levitated superconducting coil magnet. Such a compact dipole field configuration is potentially applicable to the confinement of various charged particles including positrons and electrons.

The spectra of carbon dioxide in the 3.3 µm region were recorded at three pressures using Bruker IFS 125 HR Fourier transform spectrometer and a 30 m base multipass gas cell of V.E. Zuev Institute of Atmospheric Optics SB RAS. Several lines of the 01111–00001 (ν2 + ν3) magnetic dipole band of 12C16O2 were detected and their line intensities were measured. The vibrational transition magnetic dipole moment was fitted to the observed line intensities. The fitted value of the vibrational transition magnetic dipole moment of 0.71(1)µN is substantially smaller than the value of 0.96µN obtained in the result of the analysis of the Martian atmosphere spectra (here µN is the nuclear magneton). Using the known set of the effective Hamiltonian parameters and fitted value of the vibrational transition magnetic dipole moment the list of the line parameters of this band was generated for the HITRAN database. In addition the line intensities of the R-branch of the electric dipole 01111–00001 band of the 16O12C18O isotopologue were measured for the first time.

The properties of low-lying magnetic dipole ($M$1) excitations in $^{153}$Eu were studied within a rotational invariant quasiparticle phonon model that takes into account the symmetry-restoring as well as spin-spin residual forces. The calculations show that there are purely collective $M$1 excitations lying at 2-4 MeV fragmented over orbital 1$^{+}$ states of the $^{152}$Sm core nucleus. The results were compared to the experimentally known $M$1 excitations at 2-3 MeV. A reasonably good agreement in the total transition strength, the centroid energy, and the resonance width was obtained.

Ab initio calculations of NMR shielding constants for water solvated trivalent scandium, yttrium and lanthanum cations are presented. The solvent effects of the first solvation shell are calculated explicitly using coupled cluster theory. The relativistic correction is calculated at non-correlated level. The influence of the second solvation shell is estimated at DFT level. The final NMR shielding constants define new NMR absolute shielding scales of scandium, yttrium and lanthanum and these shieldings were used for re-derivation of the nuclear magnetic dipole moments, eliminating long standing errors of ≈ 0.005 μ N .

The manipulation of atoms by using a microwave (MW) field in precise atomic measurement and atomic chips is experiencing a renaissance. In this article, we study the magnetic dipole interaction (MDI) between a neutral 87 R b atom and a single-cycle MW field. Based on the strict analytic expression of the MW pulsed field radiated by the double L -type dipole transmitter, the MDI is simulated for different initial atom states and different detunings of the MW pulse. Our results show that the MDI can reach about one times the gravity of the atom, and it can change from a defocusing force to a focusing force on the coherent state atom depending on the distance from the emitter. Finally, the transient evolution of the coherent population transfer driven by the MW pulse is discussed. We hope that our calculation may help in understanding the coupling between an ultrashort MW field and an atom.

Magnetic-dipole (M1) excitations of 18O and 42Ca nuclei are investigated within a relativistic nuclear energy density functional framework. In our last work [1], these nuclei are found to have unique M1 excitation and its sum rule, because of their characteristic structure: the system consists of the shell-closure core plus two neutrons. For a more systematic investigation of the M1 mode, we have implemented a framework based on the relativistic nuclear energy density functional (RNEDF). For benchmark, we have performed the RNEDF calculations combined with the random-phase approximation (RPA). We evaluate the M1 excitation of 18O and 42Ca, whose sum-rule value (SRV) of the M1 transitions can be useful to test the computational implementation [1]. We also apply this RNEDF method to 208Pb, whose M1 property has been precisely measured [2, 3, 4, 5]. Up to the level of the M1 sum rule, our result is in agreement with the experiments, except the discrepancy related with the quenching factors for g coefficients.

Background: Magnetic dipole (M1) excitation is the leading mode of nuclear excitation by the magnetic field, which couples unnatural-parity states. Since the M1 excitation occurs mainly for open-shell nuclei, the nuclear pairing effect is expected to play a role. As expected from the form of operator, this mode may provide the information on the spin-related properties, including the spin component of dineutron and diproton correlations. In general, the sum rule for M1 transition strength has not been derived yet. Purpose: To investigate the M1 excitation of the systems with two valence nucleons above the closed-shell core, with pairing correlation included, and to establish the M1 sum rule that could be used to validate theoretical and experimental approaches. Possibility to utilize the M1 excitation as a tool to investigate the pairing correlation in medium is also discussed. Method: Three-body model, which consists of a rigid spherical core and two valence nucleons, is employed. Interactions for its two-body subsystems are phenomenologically determined in order to reproduce the two-body and three-body energies. We also derive the M1 sum rule within this three-body picture. Conclusion: The introduced M1 sum rule can be utilized as a benchmark for model calculations of M1 transitions in the systems with two valence nucleons. The total sum of the M1 transition strength is related with the coupled spin of valence nucleons in the open shell, where the pairing correlation is unnegligible. The three-body-model calculations for 18 O, 18 Ne, and 42 Ca nuclei demonstrate a significant effect of the pairing correlations on the low-lying M1 transitions. Therefore, further experimental studies of M1 transitions in those systems are on demand, in order to validate proposed sum rule, provide a suitable probe for the nuclear pairing in medium, as well as to optimize the pairing models., 10 pages, 3 figures, 4 tables. Revised for re-submission to Phys. Rev. C

The high-efficiency injection of a low-energy positron beam into the confinement volume of a magnetic dipole has been demonstrated experimentally. This was accomplished by tailoring the three-dimensional guiding-center drift orbits of positrons via optimization of electrostatic potentials applied to electrodes at the edge of the trap, thereby producing localized and essentially lossless cross-field particle transport by means of the E×B drift. The experimental findings are reproduced and elucidated by numerical simulations, enabling a comprehensive understanding of the process. These results answer key questions and establish methods for use in upcoming experiments to create an electron-positron plasma in a levitated dipole device.

Semi-empirical transition probabilities for magnetic dipole (M1) and electric quadrupole (E2) emission lines have been derived from parametric studies of experimental energy levels in Tm3+ (Tm IV), Yb4+ (Yb V), and Er3+ (Er IV), using Cowan codes. Results are compared with those existing from ab initio calculations or from more sophisticated semi-empirical calculations. Satisfactory agreements show that simple parametric calculations can provide good predictions on line intensities, provided that experimental levels are available, allowing reliable fits of energy parameters.

The emission quenching of magnetic dipole transitions due to electromagnetic coupling to a metal nanoparticle is studied theoretically. We show that, at nanometer distances to the nanoparticle surface, the quenching is much weaker than that of electric dipole transitions, resulting in far higher radiative quantum efficiencies. This difference is explained by the fact that the electric field induced by an oscillating magnetic dipole and responsible for the energy transfer to the metal has a weaker distance dependence than the electric field of an electric dipole. Our results imply that magnetic dipole transitions may be superior to electric ones if coupling to a metallic nanoantenna over sub-10 nm distances is used to enhance optical emission from a quantum emitter.

The interaction between a high-speed neutral gas flow and dipole magnetized plasma is investigated theoretically to examine how mass, momentum, and energy are transferred to the plasma. Single-particle trajectory analysis reveals the existence of an ion-trapping region within which ions are born into closed orbits around the magnet, thus adding mass and energy to the plasma. Ion deceleration through trapping or deflection is analyzed to quantify momentum transfer to the magnetic field. The drag force and transfer rate of mass and energy from the flow to the plasma are found to scale with two dimensionless parameters: (1) a characteristic ion Larmor radius normalized by the magnet radius and (2) a characteristic neutral reaction rate normalized by the neutral gas rate of transit. The energy transfer rate is maximized at a specific reaction rate, above which increased reactivity rapidly decreases energy capture as the interaction moves away from the ion-trapping region. As the electron energy confinement time increases, there is a transition from a mode in which seed plasma is required to sustain the interaction to a high-density mode that is sustained primarily by mass and energy from the neutral flow. Two distinct flow-sustained regimes are identified that depend on the ratio of the effective ionization energy to kinetic energy of the neutral gas particles. One of the two regimes corresponds to the well-known critical ionization velocity phenomenon. The other, in which charge exchange collisions are the dominant energy transfer mechanism, has not been previously identified as a separate physical regime.

A simulation study is presented for a collisional, low-temperature dipole plasma encountered by rarefied, hypersonic neutral gas flow. A global model is developed and averaged over a toroidal control volume to describe the mass and energy exchange between the neutral stream and plasma. Simulations over a large range of magnet and freestream parameters reveal three distinct physical regimes that have significant bearing on the magnitude of plasma/flow interaction. The transitions between these regimes exhibit characteristics of resistive critical ionization, whereby the relative kinetic energy between plasma and neutral gas collisionally heats electrons, driving rapid and complete ionization of the gas. Two regime transitions are observed here with sudden exponential increases in plasma density occurring at velocity thresholds that depend on several energy loss mechanisms. The higher-velocity transition is a classical presentation of critical ionization where flow neutrals are ionized directly by plasma electrons. The other is a unique case in which charge exchange between ions and flow neutrals supplies both the particles and energy required to initiate critical ionization. This transition is distinct from any critical ionization effect reported in literature and indicates the existence of a lower critical velocity governed by collisional and diffusive effects as opposed to ionization energy losses only. Drag force on the magnetic field is considered by examining absorption and deflection of ionized flow by the dipole. The critical ionization thresholds increase the force on the magnet by up to two orders of magnitude compared to aerodynamic drag on an equivalently sized flow impediment.

Strengths of $M1$ transitions depopulating high-lying ${1}^{+}$ states and of subsequent transitions in cascades populating the first excited state were determined on the basis of large-scale shell-model calculations for the nuclide $^{54}\mathrm{Fe}$. The results reveal that the spectra of primary $M1$ transitions from ${1}^{+}$ states as well as the subsequent cascades of $M1$ transitions show an enhancement of strength toward low energy, which is similar to that found for a huge number of transitions between states of a wide spin range as observed in light-ion induced reactions. This allows, in principle, the study of low-energy $M1$ strength using photon scattering. Based on these results, intensities of $M1$ transitions under experimental conditions are estimated.

Inelastic proton scattering under extreme forward angles including $0^\circ$ and at energies of a few hundred MeV has been established as a new spectroscopic tool for the study of complete dipole strength distributions in nuclei. Such data allow an extraction of the electric dipole polarizability which provides important constraints parameters of the symmetry energy, which determine the neutron skin thickness and the equation of state (EOS) of neutron-rich matter. Also new insight into the much-debated nature of the pygmy dipole resonance (PDR) is obtained. Additionally, the isovector spin-M1 resonance can be studied in heavy nuclei, where only limited experimental information exists so far. Together with much improved results on the isoscalar spin-M1 strength distributions in $N = Z$ nuclei, these data shed new light on the phenomenon of quenching of the nuclear spin response. Using dispersion matching techniques, high energy resolution ($\Delta E/E \leq 10^{-4} \,\,$ full width at half maximum, FWHM) can be achieved in the experiments. In spherical-vibrational nuclei considerable fine structure is observed in the energy region of the isovector giant dipole resonance (IVGDR). A quantitative analysis of the fine structure with wavelet methods provides information on the role of different damping mechanisms contributing to the width of the IVGDR. Furthermore, level densities can be extracted from a fluctuation analysis at excitation energies well above neutron threshold, a region hardly accessible by other means. The combination of the gamma strength function (GSF) extracted from the E1 and M1 strength distributions with the independently derived level density permits novel tests of the Brink-Axel hypothesis underlying all calculations of statistical model reaction cross sections in astrophysical applications in the energy region of the PDR., Comment: 52 pages, 64 figures, review article submitted to Eur. Phys. J. A

Inspired by planetary magnetospheres, researchers studied the feasibility of using a levitated trap to confine particles.

A low-energy enhancement of radiative strength functions was deduced from recent experiments in several mass regions of nuclei, which is believed to impact considerably the calculated neutron capture rates. In this Letter we investigate the behavior of the low-energy $\ensuremath{\gamma}$-ray strength of the $^{44}\mathrm{Sc}$ isotope, for the first time taking into account both electric and magnetic dipole contributions obtained coherently in the same theoretical approach. The calculations are performed using the large-scale shell-model framework in a full $1\ensuremath{\hbar}\ensuremath{\omega}\text{ }\text{ }sd\text{\ensuremath{-}}pf\text{\ensuremath{-}}gds$ model space. Our results corroborate previous theoretical findings for the low-energy enhancement of the $M1$ strength but show quite different behavior for the $E1$ strength.

The effect of nuclear magnetic dipole moment of hydrogen, deuterium and tritium isotopes on the electron atomic energy has been studied and analysed in this work. The electromagnetic Hamiltonian was rewritten in terms of the orbital angular momentum $$L_e$$ of the electron, the gyromagnetic ratio $$\gamma _N$$ of the nucleus and its total angular momentum $$J_N$$ . The first-order energy correction has been derived, and this correction splits each $$\ell $$ state into $$2J_N+1$$ states. The energy corrections and the differences between the split states of the first two lowest energy states for each isotope were calculated and it is found that these two energy states are in the radiowave range.

The equations of charged particle motion in the earth’s magnetic field are analyzed. Analytical data allow us to estimate important parameters of the charge dynamics, such as the charge capture conditions, oscillation amplitude and frequency, and longitudinal drift, and also relate these parameters to the parameters of the charged particles and the height of their trajectory. The results may be used in designing space vehicles intended for investigation of the near-earth space, specifically, earth’s magnetosphere, with charged particle beams.

A new set of radiative decay parameters (oscillator strengths, transition probabilities) for spectral lines in triply ionized thulium (Tm IV) has been obtained within the framework of the pseudo-relativistic Hartree-Fock (HFR) approach. The effects of configuration interaction and core-polarization have been investigated in detail and the quality of the results has been assessed through a comparison between different HFR physical models. The spectroscopic data listed in the present paper cover electric dipole as well as magnetic dipole and electric quadrupole transitions in a wide range of wavelengths from extreme ultraviolet to near infrared.