Excitation of a magnetospheric maser through modification of the Earth’s ionosphere by high-power HF radio emission from a ground-based transmitter

A method for controlled excitation of a magnetospheric maser through the production of artificial density ducts by high-power HF radio emission from the Earth’s surface has been proposed and implemented in an in-situ experiment. Artificial density ducts allow one to affect the maser resonator system and the excitation and propagation of low-frequency electromagnetic waves in a disturbed magnetic flux tube. The experimental data presented here were obtained at the mid-latitude Sura heating facility. The characteristics of electromagnetic and plasma disturbances at outer-ionosphere altitudes were measured using the onboard equipment of the DEMETER satellite as it passed through the magnetic flux tube rested on the region of intense generation of artificial ionospheric turbulence.     

A model of Jupiter’s magnetodisk

An axially symmetric equilibrium model of Jupiter’s magnetodisk is developed in the MHD approximation that takes the plasma corotation and the centrifugal force into account. The model is constructed for two cases: (1) the magnetodisk plasma is assumed to have a uniform temperature; (2) the plasma pressure is assumed to be an adiabatic function of density. Analytical expressions for the magnetic field, current density, and magnetodisk temperature and thickness distributions are obtained as functions of the system parameters, viz., the radial distribution of plasma pressure in the equatorial plane, the transverse magnetic field in the center of the layer, and the angular velocity of the plasma rotation.     

Spatial-frequency characteristics of radio emission induced by interaction of an extensive air shower with the Earth’s surface

The spatial directional pattern of the radio emission induced by interaction of the excess electrons of an extensive air shower with the Earth’s surface was found in the approximation of perfect soil conductance. The results made it possible to determine the frequency range (≈0.2–1 MHz), within which the radio emission of the shower is maximum, provided that this emission mechanism is valid. In addition, it became possible to explain the previously observed lack of direct proportionality between the shower energy and the radio signal amplitude. It was found that this disproportionality is caused mainly by the high directivity of low-frequency (0.2–3 MHz) radiation patterns within a wide range of the values of the axial tilt.     

Plasma Resources of Jupiter＇s Main Auroral Oval

Jupiter＇s aurora exhibits three distinct regions： the satellite footprint emissions, the main oval emissions and all polar emissions. As the case of the Earth, the auroral morphology contains both qualitative and quantitative clues about magnetospheric structure and dynamics. We map along the magnetic field lines to the equatorial plane to track the plasma resources of the main oval in an equilibrium model of Jupiter＇s magnetosphere. The footprints of the satellites are good references to help us to check the mapping. We find out that the plasma of oval emissions originates from the equatorial plane with a distance of～22.0RJ, which is closer to the Jupiter than 30RJ given by the VIP4 model. However the difference does not deny the conclusion that the upward Birkeland currents produce the oval emissions.     

Adaptive synchronization of memristor-based Chuaʼs circuits

In this Letter, a memristor-based Chua?s system is presented, and the chaotic behavior of this system is demonstrated by phase portraits. This Letter also deals with the problem of adaptive synchronization control of this chaotic system using the drive–response concept, and presents an adaptive control scheme for the synchronization of memristor-based Chua?s circuit, when the parameters of the drive system are fully unknown and different with those of the response system. The sufficient condition for the adaptive synchronization has been analyzed. Moreover, the controller design method is further extended to more general cases, where the physical plant contains parameter uncertainties, represented in either polytopic or structured frameworks. Numerical simulations are used to demonstrate these results.     

Statistical properties of cooperative emission of an ensemble of nonisochronous electrons–oscillators

Effect of shot noise and energy spread of particles on the statistical properties of cooperative emission of an ensemble of nonisochronous electrons–oscillators is analyzed. The dependences of the rootmean-square deviation of the peak radiation power and the autophasing time on the number of particles are determined in the absence of the energy spread. Even a minor energy spread of 4% leads to a decrease in the maximum possible power of cooperative emission.     

Registering Jovian electrons in the Earth’s orbit

The results from observing Jovian electrons in the vicinity of the Earth are discussed. Variations in Jovian electron flows are observed during 14 rotations of the Sun in 2007–2008. The results are analyzed by assuming the existence of magnetic traps in the space between the Sun and Jupiter that are filled with electrons near Jupiter, and are then registered when the traps pass by the Earth. The average period of variation in the Jovian electron flow during the 14 solar rotations is 26.2 days instead of the expected synodic period of the Sun–Earth system equal to 27.3 days. An explanation for this phenomenon is proposed.     

Kβ X-ray emission from He-like ions

Relativistic calculations on the energies and electric dipole rates of K_β X-rays from 1s3p(¹P₁,³P₁)-1s² (¹S₀) transitions for He-like ions in the range Z=14–54 are carried out using multi-configuration Dirac–Fock (MCDF) wave functions in the active space interaction approach. The contributions from Breit interaction and quantum electrodynamics have also been included in the calculation. An attempt has been made to find a scaling expression for Breit energy in terms of Zα .The scaled Breit energies are in good agreement with the earlier accurate relativistic results and this ensures the reliability of our scaling procedure. The behavior of MCDF wavefunctions for a given J in the non-relativistic limit has also been studied. The calculated K_β X-ray energies and rates agree well with other available experimental and theoretical values.     

Ultrafast blue light emission from SiC nanowires

Cubic silicon carbide (SiC) nanowires are synthesized in a catalyst-assisted process. The nanowires with diameter of - 40 nm exhibit strong blue light emission at room temperature under ultraviolet (UV) femtosecond laser excitation. The photon energy of peak emission is higher than the energy bandgap of cubic SiC which shows involvement of quantum confinement effect. The ultrafast fluorescence is deconvoluted by Monte-Carlo method. The results show two ultrafast decay processes whose lifetimes are about 26 and 567 ps respectively. The mechanisms of such ultrafast processes are discussed.     

Kinematics of Cherenkov’s effect with noninvariant velocity of light

The kinematics of Cherenkov’s effect is considered for an electron moving in the Minkowski space with universal time and velocity of light c = c ₀ (1 + v ²/c ₀²)^1/2, where c ₀ = 3⋅10 m/s is the invariant constant and v is the particle velocity. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 1, pp. 47–50, January, 2009.     

The half-infinite XXZ chain in Onsagerʼs approach

The half-infinite XXZ open spin chain with general integrable boundary conditions is considered within the recently developed ‘Onsager?s approach’. Inspired by the finite size case, for any type of integrable boundary conditions it is shown that the transfer matrix is simply expressed in terms of the elements of a new type of current algebra recently introduced. In the massive regime −1<q<0$-1<q<0$, level one infinite dimensional representation (q-vertex operators) of the new current algebra are constructed in order to diagonalize the transfer matrix. For diagonal boundary conditions, known results of Jimbo et al. are recovered. For upper (or lower) non-diagonal boundary conditions, a solution is proposed. Vacuum and excited states are formulated within the representation theory of the current algebra using q-bosons, opening the way for the calculation of integral representations of correlation functions for a non-diagonal boundary. Finally, for q generic the long standing question of the hidden non-Abelian symmetry of the Hamiltonian is solved: it is either associated with the q-Onsager algebra (generic non-diagonal case) or the augmented q-Onsager algebra (generic diagonal case).     

Studying track electrons in frozen aqueous solutions by means of emission Mössbauer spectroscopy

It is shown by means of emission Mössbauer spectroscopy that the reactivity of NO ₃ ^? cations with quasi-free track electrons exceeds those of H₃O⁺, ClO ₄ ^? , and HSO ₄ ^? ions by a factor of only three. This is in drastic contradiction to published assertions that these values differ by two orders of magnitude. An explanation for this discrepancy is proposed.     

Nitrogen optical emission during nanosecond laser ablation of metals: prompt electrons or photo-ionization?

Experiments on the interaction of metal targets with a Nd:YAG laser beam ( \(\lambda \)  = 1,064 nm, intensity \(10^{10}\) – \(10^{11}\,\hbox {W/cm}{^2}\) ) are carried out in a finite Nitrogen pressure environment. The observed \(\hbox {N}_2\) spectra are unambiguous evidence of the existence of an ionization and excitation source, arriving at the observation volume prior to the plume. Such a source can be either prompt electrons or VUV radiation. The analysis reveals that the prompt electron interpretation requires energies in excess of 1 keV, incompatible with any acceleration mechanisms relevant for such laser intensities. On the other hand, VUV radiation is sufficiently strong to explain the observed spectra.     

MeV – proton emission from ultrafast laser-driven microparticles

Propagation of a high intensity (10¹⁹ W/cm²) ultrashort (35 fs) laser pulse through a cloud of water spheres (150 nm diameter) results in hot electron driven proton acceleration up to 1 MeV. It is suggested that during the propagation of the short pulse through the low density wing of the cloud, the leading pulse pedestal is reduced owing to absorption by the preplasma created. Then, the high-intensity peak of the pulse propagates through this underdense plasma and interacts with the high-density inner part of the cloud, which has not been transformed into an underdense plasma so that a sheath acceleration process at each individual microsphere can take place. The observed proton spectra show strong modulations, which are interpreted within the framework of a known fluid-expansion model incorporating two hot-electron populations with significantly different densities and temperatures. PACS 52.50.Jm; 52.38.Kd; 41.75.Jv     

Weinbergʼs approach to nucleon–nucleon scattering revisited

We propose a new, renormalizable approach to nucleon–nucleon scattering in chiral effective field theory based on the manifestly Lorentz invariant form of the effective Lagrangian without employing the non-relativistic expansion. For the pion-less case and for the formulation based on perturbative pions, the new approach reproduces the known results obtained by Kaplan, Savage and Wise. Contrary to the standard formulation utilizing the non-relativistic expansion, the non-perturbatively resummed one-pion exchange potential can be renormalized by absorbing all ultraviolet divergences into the leading S-wave contact interactions. We explain in detail the differences to the non-relativistic formulation and present numerical results for two-nucleon phase shifts at leading order in the low-momentum expansion.     

Compton mechanism of γ-quanta emission in the extremely inelastic scattering of electrons by hadrons

The Compton mechanism at the emission of -quanta, in the extremely inelastic scattering of charged leptons by hadrons is investigated using the quark-parton model. The cross section of the e^– + qe^– + q + (q-quark) process, in which two particles are recorded in the final state corresponding to the Compton mechanism, is calculated. The structural functions of the extremely inelastic scattering of electrons by nucleons are obtained for this mechanism. A violation of the gauge invariance of extremely inelastic scattering due to consideration of the radiational corrections is pointed out.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 1, pp. 9–13, January, 1982.