Coupling Of External Electromagnetic Fields Research Articles

ESTUDIO ANALÍTICO Y POR SIMULACIÓN MONTE CARLO DE LA INFLUENCIA DECAMPOS MAGNÉTICOS INTENSOS EN LA TRAYECTORIA DE ELECTRONES CONENERGÍAS TÍPICAS DE RADIOTERAPIA MRI-LINAC

Both analytical and numerical methods have proven to be suitable for describing radiation transport and interactions. The standard Boltzmann formalism derived from statistical mechanics requires to be specifically re-formulated to account for the interactions with external electromagnetic fields. Verifying the proper implementation of the external electromagnetic field coupling in Monte Carlo simulation codes is a key issue to confirm the feasibility of using such a tool to describe complex applications like image-guided radiotherapy based on integrating magnetic resonance scanner to the radiant field of ionizing radiation along with the subsequent dosimetric effects. The present work reports on the feasibility and reliability of the Monte Carlo FLUKA and PENELOPE main codes to assess electron trajectory in presence of strong magnetic fields. The obtained results confirm the ability of FLUKA and Penelope to model the alterations in the electron trajectories due to external magnetic field effects, also demonstrating an excellent agreement between both codes and with the theoretical-analytical model.

Physics of electromagnetically induced chirality and anti-symmetric wave transmission

ABSTRACTChiral materials possess some unusual properties which make them interesting for useful applications in nanophotonics. In this work, we review the basic techniques used to achieve electromagnetically induced chirality in initially isotropic materials and mention some of their novel operations. Next, we investigate the transmission characteristics of two different multi-level atomic models in which chirality is introduced by magnetoelectric cross coupling of external electromagnetic fields with atomic transitions, leading to quantum coherence. The left-(lcp) and right-circularly polarized (rcp) beams, the two eigenmodes of a chiral medium, are shown to transmit in an anti-symmetric manner with respect to the probe field detuning and control field magnitude variations. This selective transmission of a particular mode at specific detunings may find applications in optical isolation and storage. We further demonstrate that the driving control fields and their effective phase can be used as tuning knobs to manipulate the medium's birefringence and the transmission of the eigenmodes.

A Fast and Efficient Analytical Modeling Approach for External Electromagnetic Field Coupling to Transmission Lines in a Metallic Enclosure

A fast and efficient analytical approach based on the extended Baum-Liu-Tesche (BLT) equation is proposed in this paper to evaluate the external electromagnetic field coupling to transmission lines (TLs) loaded in a metallic enclosure with apertures. The scattering matrix to describe the aperture coupling characteristics required in the BLT equation is effectively derived based on the equivalent circuit theory. The analytical modeling function for calculating internal modal fields coupling to TLs is investigated and developed. Thus, the extended BLT equation can be directly employed in the assessment of current induced at the loads of TLs in the enclosure, which is illuminated by external electromagnetic fields. Via different case studies, the results calculated using the proposed analytical approach have been validated and have been in a good agreement with those simulated by numerical methods. The computational efficiency, in terms of time and memory, has also been improved much for the electromagnetic interference problems.

ANALYSIS OF ELECTROMAGNETIC INFLUENCE ON STEEL PIPELINES FROM THE ELEMENTS OF ELECTRIC POWER SYSTEM

A b s t r a c t: Power transmission lines often share same corridors with steel pipelines for oil and gas. When phase to ground fault occurs, high voltages may appear on the pipelines due to different mechanisms of mutual coupling. These voltages propagate at long distances from the fault location, and may pose a serious threat for the safety of the personnel and integrity of the pipeline. To provide adequate protection, calculation of the mutual coupling is required during the design stage of systems. Induced voltages are strongly influenced by the disposition of the both systems, their configuration and characteristics, elements that mutually interact etc. In this paper, we analyze induced voltages on practical pipeline system. Parametric analysis will show how far interventions on both systems can influence the induced voltages. Key words: electromagnetic influence; gas; oil; pipelines; safety REFERENCES: [1] Guide on the Influence of High Voltage AC Power Systems on Metallic Pipelines. Paris, CIGRE Working Group 36. 02, 1995. [2] Directives Concerning the Protection of Telecommunication Lines аgainst Harmful Effects from Electric Power and Electrified Railway Systems. Volume II: Calculating Induced Voltages and Currents in Practical Cases, Geneva, CCITT, 1989. [3] Guide for Assessment of Transferred EPR on Telecommunication Systems Due to Faults in A.C. Power Systems. Paris, CIGRE Working Group C4. 207, 2014. [4] Sunde. E. D.: Earth Conduction Effects in Transmission Systems. New York: Dover, 1968. [5] Wait, J. R.: Theory of Wave Propagation along a Thin Wire Parallel to an Interface. Radio Science. Vol. 7. pp. 675–679 (1972). [6] Directives Concerning the Protection of Telecommunication Lines against Harmful Effects from Electric Power and Electrified Railway Systems, Volume III, Capacitive, Inductive and Conductive Coupling: Physical theory and calculation methods, Geneva, CCITT, 1989. [7] Grcev, L., Dawalibi, F.: An Electromagnetic Model for Transients in Grounding Systems. IEEE Trans. on Power Delivery. Vol. 5. pp. 1733–1781 (1990). [8] Smith, A. A.: Coupling of External Electromagnetic Fields to Transmission Lines. New York: Wiley, 1977. [9] МКС EN 50443:2012 – Effects of Electromagnetic Interference on Pipelines Caused by High Voltage A.C. Electric Traction Systems and/or High Voltage A.C. Power Supply Systems, Brussels: CENELEC, 2011. [10] NACE SP0177-2014 – Mitigation of Alternating Current and Lightning Effects on Metallic Structures and Corroion Control Systems. Houston, Texas: NACE International, 2014. [11] Mangionem, S.: Compact Model of a Combined Overhead-Cable Line for Ground Fault Application Transfer Analysis, Proc. of the 5 th WHEAS Int. Conf. on Power Systems and Electromagnetic Compatibility. August 23–25, 2005, pp. 251–256.

Electrical characterization of airborne vehicle exhaust plume

The induced current and voltage on the skin of an airborne vehicle due to the coupling of external electromagnetic field could be altered in the presence of ionized exhaust plume. So in the present work, a theoretical analysis is done to estimate the electrical parameters such as electrical conductivity and permittivity and their distribution in the axial and radial directions of the exhaust plume of an airborne vehicle. The electrical conductivity depends on the distribution of the major ionic species produced from the propellant combustion. In addition it also depends on temperature and pressure distribution of the exhaust plume as well as the generated shock wave. The chemically reactive rocket exhaust flow is modeled in two stages. The first part is simulated from the combustion chamber to the throat of the supersonic nozzle by using NASA Chemical Equilibrium with Application (CEA) package and the second part is simulated from the nozzle throat to the downstream of the plume by using a commercial Computational Fluid Dynamics (CFD) solver. The contour plots of the exhaust parameters are presented. Eight barrel shocks which influence the distribution of the vehicle exhaust parameters are obtained in this simulation. The computed peak value of the electrical conductivity of the plume is 0.123 S/m and the relative permittivity varies from 0.89 to 0.99. The attenuation of the microwave when it is passing through the conducting exhaust plume has also been presented.

Raman spectroscopy of collective modes in charge‐density‐wave systems: the mean‐field microscopic theory

AbstractThe electron‐mediated coupling of external electromagnetic fields and Raman‐active oscillations is derived for a general electronic model with multiple bands using the adiabatic approach and the explicit diagrammatic approach. The theory is illustrated on the quasi‐one‐dimensional (Q1D) quarter‐filled charge‐density‐wave (CDW) model. It is shown how the long‐range Coulomb forces and the single‐electron relaxation processes affect the Raman spectroscopy of the amplitude‐oscillation mode in clean CDW systems. It is also argued that the adiabatic treatment of the photon‐phonon coupling functions can be safely used in this case. Copyright © 2008 John Wiley & Sons, Ltd.

Theory of strong outcoupling from Bose-Einstein condensates

We study the dynamics of a magnetically trapped Bose-Einstein condensate in the presence of an external electromagnetic field coupling trapped, untrapped and antitrapped Zeeman sublevels. For large condensates an approximate analytical solution of the coupled Gross-Pitaevskii equations is given in the regime of strong outcoupling. The theory is developed for the cases of rf-outcoupling within a hyperfine manifold of states, micowave-outcoupling connecting states in two different hyperfine manifolds, and Raman outcoupling.

Coupling of external electromagnetic fields to underground multiconductor cable transmission systems

In this paper, a general model for voltage and currents induced by the primary and secondary field couplings in a multiconductor cable system buried in lossy earth, and illuminated by an external electromagnetic field is presented. Generalized form of equivalent transmission line equations (ETLEs) obtained from this model are presented, which could analyze many of the associated problems, involving the field couplings in underground transmission systems. These equations are then used to derive general solutions for the currents and potentials induced by the external fields along the underground conductors.

Coupling of external electromagnetic fields to transmission lines

Coupling of external electromagnetic fields to transmission lines

Coupling of external electromagnetic fields to transmission lines

Coupling of external electromagnetic fields to transmission lines

Coupling of External Electromagnetic Fields to Transmission Lines

Coupling of External Electromagnetic Fields to Transmission Lines