Monopole System Research Articles

Experimental and computational dynamic response comparison of hybrid and mono windmill towers considering soil–structure interaction

In countries like India, wind turbine heights are rapidly increasing to harvest more wind energy at a given location. In recent years, due to increase in hub height of windmill likelihood, soil lying below foundation may influence dynamic response of wind turbines. By increasing the height of the conventional monopole supporting system, it becomes slender and dynamically sensitive under the influence of soil below foundation; therefore, in the present investigation, hybrid supporting system is proposed to avoid slenderness effect of monopole system. A 1:40 scaled model of 78-m-high conventional monopole windmill and hybrid windmill comprised of nacelle, rotor mass and supporting tower are prepared in the laboratory. To study the behavior of both the towers under operational dynamic loads of rotor, laboratory tests were conducted on scaled model considering soil below foundation. Simulations of experimental analysis are presented for multi-degree of freedom turbine structure subjected to dynamic loading of rotor considering soil stiffness below base. It is examined in terms of displacement in time domain, shear at base of tower and response spectra. From laboratory tests and its simulation, it can be concluded that hybrid supporting system are recommended for windmill towers with higher hub heights considering soil stiffness below foundations.

Type II critical behavior of gravitating magnetic monopoles

I study type II critical collapse in the spherically symmetric gravitating magnetic monopole system. This is an Einstein-Yang-Mills-Higgs system with two matter fields: a field parametrizing the scalar field gauged under $SU(2)$ and a field parametrizing the gauge field. This system offers interesting differences compared to what is commonly found for type II collapse in other systems. For example, instead of the critical solution sitting between collapse and complete dispersal of the matter fields, on the nonblack hole side of the critical solution, the matter fields settle down to a static and stable configuration. More interesting, however, is that I find strong evidence for the existence of two critical solutions, each with their own set of scaling and echoing exponents, which I determine numerically.

Dirac potential in a rotational dissipative quantum system

This study proposes the usage of an effective potential to investigate a dissipative quantum system with rotational velocity. After gauge transformation, a Doebner- Goldin equation (DGE) that describes the dissipative quantum system with a Dirac potential is obtained. The DGE is solved based on constraint of vertical relation between the rotational velocity field and density gradient when a harmonic oscillator model is considered. It is observed that the dissipative quantum system is directly equivalent to a monopole system and that the two gauge potentials that are given by Wu and Yang in the north and south hemispheres can be reproduced. Furthermore, a set of gauge-invariant parameters is obtained to discuss the dissipation characteristics of the system.

Recurrence approach and higher order polynomial algebras for superintegrable monopole systems

We revisit the MIC-harmonic oscillator in flat space with monopole interaction and derive the polynomial algebra satisfied by the integrals of motion and its energy spectrum using the ad hoc recurrence approach. We introduce a superintegrable monopole system in a generalized Taub-Newman–Unti–Tamburino (NUT) space. The Schrödinger equation of this model is solved in spherical coordinates in the framework of Stäckel transformation. It is shown that wave functions of the quantum system can be expressed in terms of the product of Laguerre and Jacobi polynomials. We construct ladder and shift operators based on the corresponding wave functions and obtain the recurrence formulas. By applying these recurrence relations, we construct higher order algebraically independent integrals of motion. We show that the integrals form a polynomial algebra. We construct the structure functions of the polynomial algebra and obtain the degenerate energy spectra of the model.

Dirac equation with anisotropic oscillator, quantum E3′ and Holt superintegrable potentials and relativistic generalized Yang–Coulomb monopole system

The two-dimensional Dirac equation with spin and pseudo-spin symmetries is investigated in the presence of the maximally superintegrable potentials. The integrals of motion and the quadratic algebras of the superintegrable quantum [Formula: see text], anisotropic oscillator and the Holt potentials are studied. The corresponding Casimir operators and the structure functions of the mentioned superintegrable systems are found. Also, we obtain the relativistic energy spectra of the corresponding superintegrable systems. Finally, the relativistic energy eigenvalues of the generalized Yang–Coulomb monopole (YCM) superintegrable system (a [Formula: see text] non-Abelian monopole) are calculated by the energy spectrum of the eight-dimensional oscillator which is dual to the former system by Hurwitz transformation.

Quadratic algebra for superintegrable monopole system in a Taub-NUT space

We introduce a Hartmann system in the generalized Taub-NUT space with Abelian monopole interaction. This quantum system includes well known Kaluza-Klein monopole and MIC-Zwanziger monopole as special cases. It is shown that the corresponding Schrödinger equation of the Hamiltonian is separable in both spherical and parabolic coordinates. We obtain the integrals of motion of this superintegrable model and construct the quadratic algebra and Casimir operator. This algebra can be realized in terms of a deformed oscillator algebra and has finite dimensional unitary representations (unirreps) which provide energy spectra of the system. This result coincides with the physical spectra obtained from the separation of variables.

Operating characteristic analysis of a 400 mH class HTS DC reactor in connection with a laboratory scale LCC type HVDC system

High temperature superconducting (HTS) devices are being developed due to their advantages. Most line commutated converter based high voltage direct current (HVDC) transmission systems for long-distance transmission require large inductance of DC reactor; however, generally, copper-based reactors cause a lot of electrical losses during the system operation. This is driving researchers to develop a new type of DC reactor using HTS wire.The authors have developed a 400mH class HTS DC reactor and a laboratory scale test-bed for line-commutated converter type HVDC system and applied the HTS DC reactor to the HVDC system to investigate their operating characteristics. The 400mH class HTS DC reactor is designed using a toroid type magnet. The HVDC system is designed in the form of a mono-pole system with thyristor-based 12-pulse power converters.In this paper, the investigation results of the HTS DC reactor in connection with the HVDC system are described. The operating characteristics of the HTS DC reactor are analyzed under various operating conditions of the system. Through the results, applicability of an HTS DC reactor in an HVDC system is discussed in detail.

Dynamics of slender monopoles and anti-monopoles in non-Abelian superconductor

Low energy dynamics of magnetic monopoles and anti-monopoles in the U(2) gauge theory is studied in the Higgs (non-Abelian superconducting) phase. The monopoles in this superconducting phase are not spherical but are of slender ellipsoid which are pierced by a vortex string. We investigate scattering of the slender monopole and anti-monopole, and find that they do not always decay into radiation, contrary to our naive intuition. They can repel, make bound states (magnetic mesons) or resonances. Analytical solutions including any number of monopoles and anti-monopoles are obtained in the first non-trivial order of rigid-body approximation. We point out that some part of solutions of slender monopole system in 1+3 dimensions can be mapped exactly onto the sine-Gordon system in 1+1 dimensions. This observation allows us to visualize dynamics of monopole and anti-monopole scattering easily.

A RTDS Model for Simulating HVDC Transient Valve Voltage during Commutation Period

This paper presents a RTDS model applied to simulate periodic commutation impulse voltage of HVDC convent valve. The model’s main configure and basic parameters are matching to a typical monopole system which include 12-pulse converters of rectifier and inverter, convert-transformers, DC transmission line, DC filters and AC equivalent power network. Among the system model, the valve components of rectifier are User-Define-Component (UDC) model with RC branch for describing detail valve internal. And also, discrete time step apply 2.5μS non real-time of RTDS for complying with high frequency transient. The validation test is carried out and the result show that the model can simulate accurately valve voltage waveform.

Propagation of magnetic charge monopoles and Dirac flux strings in an artificial spin-ice lattice

We systematically investigate magnetic reversal of permalloy islands in a square spin-ice geometry with in situ Lorentz microscopy. Differential phase imaging reveals the presence of a flux channel similar to a Dirac string between the magnetic charge monopoles during the reversal. Analysis of the phase images shows that positively and negatively charged monopoles always move together with the flux channel. Statistical analysis of monopole populations and system correlations shows the emergence of a highly frustrated state for low magnetizations. This state is explained by a strong influence of charge ordering, which limits monopole densities.

Quantum energies and tensorial central charges of confined monopoles

We study different aspects of monopoles in the Higgs phase which are confined by (non-abelian) vortices in \cal{N}=2 SQCD with gauge group U(N) and N_f >= N massive flavors, including generalized FI-terms. We compute in particular the perturbative quantum corrections for (multiple) confined monopoles and identify an anomalous contribution in the central charge. For N_f = N the results match the quantum corrections for kinks in two-dimensional CP^{N-1} models. To regulate the theory we embedded it in a six-dimensional model with constant U(1) background fields which generate the masses upon dimensional reduction. We discuss the (local) susy algebra and its representations including tensorial central charges, which are carried by the confined monopoles, in an SU(2)_R covariant way. The resulting SU(2)_R covariant 1/4 BPS equations show that there is no correlation between the SU(2)_R and the spatial orientation of the confined monopole system. However, at the quantum level we find that supersymmetry links the spatial SU(2) with the R-symmetry SU(2)_R.

Generalized Kaluza–Klein monopole, quadratic algebras and ladder operators

We present a generalized Kaluza–Klein monopole system. We solve this quantum superintegrable system on a Euclidean Taub Nut manifold using the separation of variables of the corresponding Schrödinger equation in spherical and parabolic coordinates. We present the integrals of motion of this system, the quadratic algebra generated by these integrals, the realization in terms of a deformed oscillator algebra using the Daskaloyannis construction and the energy spectrum. The structure constants and the Casimir operator are functions not only of the Hamiltonian but also of other two integrals commuting with all generators of the quadratic algebra and forming an Abelian subalgebra. We present another algebraic derivation of the energy spectrum of this system using the factorization method and ladder operators.

Wavefield simulation and data-acquisition-scheme analysis for LWD acoustic tools in very slow formations

Propagating wavefields from monopole, dipole, and quadrupole acoustic logging-while-drilling (LWD) tools in very slow formations have been studied using the discrete wavenumber integration method. These studies examine the responses of monopole and dipole systems at different source frequencies in a very slow surrounding formation, and the responses of a quadrupole system operating at a low source frequency in a slow formation with different S-wave velocities. Analyses are conducted of coherence-velocity/slowness relationships (semblance spectra) in the time domain and of the dispersion characteristics of these waveform signals from acoustic LWD array receivers. These analyses demonstrate that, if the acoustic LWD tool is centralized properly and is operating at low frequencies (below 3 kHz), a monopole system can measure P-wave velocity by means of a “leaky” P-wave for very slow formations. Also, for very slow formations a dipole system can measure the P-wave velocity via a leaky P-wave and can measure the S-wave velocity from a formation flexural wave. With a quadrupole system, however, the lower frequency limit (cutoff frequency) of the drill-collar interference wave would decrease to 5 kHz and might no longer be neglected if the surrounding formation becomes a very slow formation, with S-wave velocities at approximately 500 m/s.

BRST INVARIANCE AND DE RHAM TYPE COHOMOLOGY OF 't HOOFT–POLYAKOV MONOPOLE

We exploit the 't Hooft–Polyakov monopole to construct closed algebra of the quantum field operators and the BRST charge Q BRST . In the first-class configuration of the Dirac quantization, by including the Q BRST -exact gauge-fixing term and the Faddeev–Popov ghost term, we find the BRST invariant Hamiltonian to investigate the de Rham type cohomology group structure for the monopole system. The Bogomol'nyi bound is also discussed in terms of the first-class topological charge defined on the extended internal two-sphere.

Charge-monopole molecule and vanishing of the Schwinger string

As is well known [1, 2], the wave functions of charge scattering states in the magnetic monopole field are expanded in the eigenfunctions of symmetric quantum top rotation. The established direct relationship of the total momentum operators of these systems causes the Schwinger string to vanish and demonstrates that the charge and monopole system has the property of a diatomic molecule.

DISAPPEARANCE OF SCHWINGER'S STRING AT THE CHARGE–MONOPOLE "MOLECULE"

An equivalence of total angular momentum operator of charge–monopole system to the momentum operator of a symmetrical quantum top is observed. This explicitly shows the string independence of Dirac's quantization condition leading to disappearance of Schwinger's string and reveals some properties of diatomic molecule for this system.

Spectral flow of the non-supersymmetric microstates of the D1-D5-KK system

We show that a realisation of spectral flow as a coordinate transformation for asymptotically four-dimensional solutions can be extended to the non-supersymmetric case. We apply this transformation to smooth geometries describing microstates of the D1-D5-KK monopole system in type IIB supergravity compactified on a six-torus, and obtain solutions with an additional momentum charge. We study the supersymmetric and near-core limits of this construction.

NUCLEAR REACTIONS IN THE MAGNETIC MONOPOLE FIELD

The D + D → 4 He reaction can be one of the methods to count the magnetic monopole. In order to prove this, the mechanism of bound state of nucleons and monopole system is clarified. We calculated bound state of nucleon-monopole system by using the Jacobi-coordinate bases antisymmetrized molecular dynamics (or JAMD) method. This calculation is done to show the efficiency of JAMD as a first step of main subject. The binding energy of neutron and proton in the magnetic monopole field is calculated. Our results are compared with those of analytical solution.

Electric charge in interaction with magnetically charged black holes

We examine the angular momentum of an electric charge e placed at rest outside a dilaton black hole with magnetic charge Q. The electromagnetic angular momentum which is stored in the electromagnetic field outside the black hole shows several common features regardless of the dilaton coupling strength, though the dilaton black holes are drastically different in their spacetime structure depending on it. First, the electromagnetic angular momentum depends on the separation distance between the two objects and changes monotonically from eQ to 0 as the charge goes down from infinity to the horizon, if rotational effects of the black hole are discarded. Next, as the black hole approaches extremality, however, the electromagnetic angular momentum tends to be independent of the distance between the two objects. It is then precisely $eQ$ as in the electric charge and monopole system in flat spacetime. We discuss why these effects are exhibited and argue that the above features are to hold in widely generic settings including black hole solutions in theories with more complicated field contents, by addressing the no hair theorem for black holes and the phenomenon of field expulsion exhibited by extremal black holes.

A monopole near a black hole

A striking property of an electric charge near a magnetic pole is that the system possesses angular momentum even when both the electric and the magnetic charges are at rest. The angular momentum is proportional to the product of the charges and independent of their distance. We analyze the effect of bringing gravitation into this remarkable system. To this end, we study an electric charge held at rest outside a magnetically charged black hole. We find that even if the electric charge is treated as a perturbation on a spherically symmetric magnetic Reissner-Nordstrom hole, the geometry at large distances is that of a magnetic Kerr-Newman black hole. When the charge approaches the horizon and crosses it, the exterior geometry becomes that of a Kerr-Newman hole, with electric and magnetic charges and with total angular momentum given by the standard value for a charged monopole pair. Thus, in accordance with the "no-hair theorem," once the charge is captured by the black hole, the angular momentum associated with the charge monopole system loses all traces of its exotic origin and is perceived from the outside as common rotation. It is argued that a similar analysis performed on Taub-NUT space should give the same result.