Parallel Electromagnetic Field Research Articles

Topological transition in a parallel electromagnetic field

Topological transition in a parallel electromagnetic field

Experimental study of the heat transfer characteristics of plasma jets in circular tubes under applied magnetic fields with different orientations

Numerical studies have demonstrated that heat transfer between magnetogasdynamic flow in a tube with the tube wall can be regulated via the application of magnetic fields. However, the development of corresponding thermal energy control applications is limited owing to a lack of effective experimental verification of these numerical findings. The present study addresses this issue by developing an experimental system for studying the effects of applied magnetic fields lying parallel and perpendicular to the direction of flow on the convective heat transfer of plasma jets generated by a dielectric barrier discharge (DBD) reactor in circular tubes, where the heat transfer parameters within the tube are calculated according to temperature measurements on the outer wall of the tube. The results demonstrate that both types of applied magnetic fields tend to suppress heat transfer between the plasma jet and the tube walls, where the effect of the perpendicular electromagnetic field on the heat transfer is anisotropic, while that of the parallel electromagnetic field is isotropic. In addition, the magnetic field intensity, the excitation voltage of the DBD reactor, and the airflow velocity at the inlet are all demonstrated to have regulatory effects on the observed heat transfer between the plasma jet and tube walls. These results lend considerable substance to the findings of numerical studies indicating that the geometrical parameters and intensities of magnetic fields must be coordinated with the specific requirements and flow parameters inherent in practical applications.

COMPUTATION OF QUASISTATIC ELECTROMAGNETIC FIELDS OF COMPLEX ELECTRIC POWER FACILITIES

: Accurate computation of low-frequency quasistatic electromagnetic fields is important in the design of electricity transmission and conversion devices. This work presents the theoretical groundwork of a computation using integral equations. The procedures for solving these equations are defined by applying the method of moments and the point matching method. The unknown distribution of the source function density on the thin-wire elements is approximated by the third degree polynomials. On rectangular planes the approximation of an unknown source function is achieved by means of bilinear elements. A program has been developed for the parallel electromagnetic field computation based on the described method.

Parallel full-wave electromagnetic field analysis based on domain decomposition method

Parallel full-wave electromagnetic field analysis based on domain decomposition method

Chirality imbalance and chiral magnetic effect under a parallel electromagnetic field

We study the time evolution of the chirality imbalance $n_5$ and the chiral magnetic effect (CME) under the external parallel electromagnetic fields without assuming the artificial chiral asymmetric source. We adopt the time-dependent Sauter-type electric and constant magnetic field, and obtain analytical solutions of the Dirac equation for a massive fermion. We use the point-split regularization to calculate the vacuum contribution in the gauge invariant way. As a result, we find that $n_5$ and CME current increase substantially as the electric field increases, and stay finite after the electric field is switched off. The chirality imbalance and CME current are shown to consist of a dominant contribution, which is essentially proportional to relativistic velocity, and a small oscillating part. We find a simple analytical relation between $n_5$ and the fermion pair-production rate from the vacuum. We also discuss dynamical origin of the chirality imbalance in detail.

Dynamically assisted Schwinger mechanism and chirality production in parallel electromagnetic field

We study particle and chirality production from the vacuum in the presence of a slow strong parallel electromagnetic field superimposed by a fast weak perturbative electromagnetic field. We derive an analytical formula for the particle and chirality production number based on the perturbation theory in the Furry picture. With the formula, we analytically discuss the interplay and dynamical assistance between the Schwinger mechanism and one-photon pair production and clarify effects of a parallel slow strong magnetic field. We also show that the dynamical assistance can significantly enhance chirality production, and that a sizable amount of chirality can be produced even for massive particles. Phenomenological applications including heavy-ion collisions and intense laser experiments are also discussed.

Effects of a parallel electromagnetic field in the three-flavor Nambu–Jona-Lasinio model

In this work, we explore the ground state of QCD system and the relevant collective modes in a parallel electromagnetic (EM) field within the effective three-flavor Nambu--Jona-Lasinio model. From the features of neutral chiral condensates, three critical EM fields are identified in our study: $e\bar{I}_2^{c_i}~(i=1,2,3)$. Moreover, competition between QCD and QED anomalies is found: the negativeness of $\pi_{\rm d}^*$ and $\pi_{\rm s}^*$ is a signal of QCD anomaly dominance for all the flavors, and the positiveness of $\pi_{\rm s}^*$ beyond $e\bar{I}_2^{c_1}$ indicates QED anomaly dominance for strange quark. For the lowest-lying neutral collective modes, the masses of $\Pi$ and $H$ modes reduce to zero around the critical EM fields and the scalar-pseudoscalar components are exchanged between $\Sigma$ and $H$ modes, as can be seen in the crossing structure.

Nambu–Jona-Lasinio model in a parallel electromagnetic field

We explore the features of the UA(1) and chiral symmetry breaking of the Nambu–Jona-Lasinio model without the Kobayashi–Maskawa–'t Hooft determinant term in the presence of a parallel electromagnetic field. We show that the electromagnetic chiral anomaly can induce both finite neutral pion condensate and isospin-singlet pseudo-scalar η condensate and thus modifies the chiral symmetry breaking pattern. In order to characterize the strength of the UA(1) symmetry breaking, we evaluate the susceptibility associated with the UA(1) charge. The result shows that the susceptibility contributed from the chiral anomaly is consistent with the behavior of the corresponding η condensate. The spectra of the mesonic excitations are also studied.

Competition between magnetic catalysis effect and chiral rotation effect

In this work, we explore the competition between magnetic catalysis effect and chiral rotation effect in a general parallel electromagnetic field within the effective Nambu--Jona-Lasinio model. For a given electric field $E$ at zero temperature, the mass gap shows three different features with respect to an increasing magnetic field $B$: increasing monotonically, decreasing after increasing and decreasing monotonically. By making use of strong magnetic field approximation, we illuminate that this is due to the competition between catalysis effect and chiral rotation effect induced both by the magnetic field, and a critical electric field $\sqrt{eE_c}=86.4~{\rm MeV}$ is found beyond which the mass gap will eventually decrease at large $B$. As only large magnetic field is relevant for the derivation, the critical electric field does not depend on the temperature $T$ or chemical potential $\mu$.

GPU-Based Massively Parallel 3-D HIE-FDTD Method for High-Speed Electromagnetic Field Simulation

This paper describes the implementation and estimation of a hybrid implicit-explicit (HIE)-finite-difference time-domain (FDTD) method on graphics processing unit (GPU) for massively parallel electromagnetic field simulation. The HIE-FDTD method was proposed for the analysis of the shielding effectiveness of an enclosure and is very useful for the simulation of computational domain with thin unit cell such as printed circuit board. Since the computational domain can be divided arbitrarily along the x- and y-directions in the HIE-FDTD method, this method can be suitable for the parallel computing. Thus, the HIE-FDTD method is implemented on GPU and applied to the large-scale problems. Finally, it is shown that the performance of the HIE-FDTD method on GPU is drastically superior to the HIE-FDTD method on single CPU.

Theoretical background of parallel electromagnetic field computations

Theoretical background of parallel electromagnetic field computations

Minimal electromagnetic coupling in elementary quantum mechanics; a group theoretical derivation

The equation of motion of a spinless quantum particle in an external uniform parallel electromagnetic field is derived from the symmetry of the field by group theoretical techniques. The minimal coupling is obtained directly, without a detour via the free particle equation. This derivation, which is valid in a Galilean as well as in a Poincare framework, is a contribution to the recasting process of quantum mechanics in the spirit of a paper by Levy-Leblond (1975).