Research on load balancing of parallel component programs based on quantum particle swarm optimization algorithm

Parallel component applications are often deployed on heterogeneous clusters. Load balancing is very important for their performance requirement. Existing load balancing methods have high performance cost and poor balance effect. Based on the analysis of structures of parallel component applications, we established the mathematical model of load balancing for parallel components on heterogeneous clusters. We use the quantum particle swarm optimization algorithm to search the optimal solution of the proposed mathematical model and determine the best load balancing scheme. Comparing with the methods based on real-time detection and other swarm intelligence optimization algorithms, our method has lower balance cost, less number of iterations and better performance.

Ion acoustic solitary waves in magnetized anisotropic nonextensive plasmas

The nonlinear propagation of ion-acoustic (IA) electrostatic solitary waves (SWs) is studied in a magnetized electron–ion (e–i) plasma in the presence of pressure anisotropy with electrons following Tsallis distribution. The Korteweg–de Vries (KdV) type equation is derived by employing the reductive perturbation method (RPM) and its solitary wave (SW) solution is determined and analyzed. The effect of nonextensive parameter q, parallel component of anisotropic ion pressure p 1, perpendicular component of anisotropic ion pressure p 2, obliqueness angle θ, and magnetic field strength Ω on the characteristics of SW structures is investigated. The present investigation could be useful in space and astrophysical plasma systems.

Integral Equations for Problems on Wave Propagation in Near-Earth Plasma

We consider the solutions of two integrodifferential equations in this work. These equations describe the ultra-low frequency waves in the dipol-like model of the magnetosphere in the gyrokinetic framework. The first one is reduced to the homogeneous, second kind Fredholm equation. This equation describes the structure of the parallel component of the magnetic field of drift-compression waves along the Earth’s magnetic field. The second equation is reduced to the inhomogeneous, second kind Fredholm equation. This equation describes the field-aligned structure of the parallel electric field potential of Alfvén waves. Both integral equations are solved numerically.

Constraints on large-scale magnetic fields in the intergalactic medium using cross-correlation methods

ABSTRACT Large-scale coherent magnetic fields in the intergalactic medium (IGM) are presumed to play a key role in the formation and evolution of the cosmic web, and in large-scale feedback mechanisms. However, they are theorized to be extremely weak, in the nano-Gauss regime. To search for a statistical signature of these weak magnetic fields, we perform a cross-correlation between the Faraday rotation measures (RMs) of 1742 radio galaxies at z > 0.5 and large-scale structure at 0.1 < z < 0.5, as traced by 18 million optical and infrared foreground galaxies. No significant correlation signal was detected within the uncertainty limits. We are able to determine model-dependent 3σ upper limits on the parallel component of the mean magnetic field strength of filaments in the IGM of ∼30 nG for coherence scales between 1 and 2.5 Mpc, corresponding to a mean upper bound RM enhancement of ∼3.8 rad m−2 due to filaments along all probed sightlines. These upper bounds are consistent with upper bounds found previously using other techniques. Our method can be used to further constrain intergalactic magnetic fields with upcoming future radio polarization surveys.

Transport ratios of the kinetic Alfvén mode in space plasmas

<p>Electric field properties of the kinetic Alfvén mode are analytically studied by constructing the dielectric tensor of the plasma using the linear Vlasov theory and reducing (and identifying) the tensor elements into that of the fluid picture such as the polarization drift, the Hall current, and the diamagnetic current. Off-diagonal dielectric responses do not primarly contribute to the dispersion relation of the kinetic Alfvén mode, but play an important role in the electric field polarization (field rotation sense around the mean magnetic field) and parallel component of the field. The polarization becomes more circular and the parallel component enhances at larger perpendicular wavenumbers. Analytic expression of fluctuation sense serves as a tool to identify the kinetic Alfvén mode in space plasma observations.</p>

An up-to-date Mapping for the Movement and the Deformation of the Sinai Micro-plate from a Combined GPS Velocity Field

<p>We use combined GPS velocities covering Sinai peninsula to estimate the current rates across the Sinai micro-plate boundaries. New GPS velocities were estimated for 67 sites located within and around Sinai (Arabia, Eurasia and Nubia plates) covering the time span 1999-2018 using GAMIT/GLOBK 10.6 (Herring et al., 2015). We have combined our velocity field with two other recent solutions of GPS sites located around Sinai area. We used the VELROT tool from GAMIT/GLOBK package to combine all solutions resulting in a velocity field of 265 GPS sites in ITRF2018. Then, we selected 61 sites that represent the Sinai plate interior to estimate the Euler pole of Sinai micro-plate. Our computed the Euler pole parameters, latitude, longitude, and angular velocity for Sinai are 53.3±1.8°, -7.8±2.2°, and 0.451±0.014°/Ma, respectively, which are comparable to previous estimates, but with better uncertainties. The relative block motions at the Sinai plate boundaries are estimated using the DEFNODE code (McCaffrey, 2002) by minimizing the GPS residual motions within the blocks in a least squares sense. Our block motion model for Sinai sub-plate shows a fault-parallel velocity at the Gulf of Aqaba of 4.7-4.5 mm/yr, associated with negligible fault-normal component, which decreased toward the north direction along the Dead Sea Transform Fault. On the other hand, an opening rate of 3 mm/yr is estimated at the southern part of the Gulf of Suez with negligible fault-parallel component. At central and northern parts of the Gulf of Suez, the opening rate decreases until it vanished at the northern part of the Suez Canal while the fault-parallel component increases.</p>

Enhancement of Magneto-optic Kerr effect of YIG nanoparticle by backscattering suppression

Magneto-optic Kerr effect (MOKE) enhancement is studied for Yttrium Iron Garnet (YIG) nanoparticle. The MOKE is quantified by the ratio of the polarization components of reflected wave, namely between the perpendicular component to the parallel component with respect to the polarization of the incident wave. Thus, the enhancement of MOKE can be obtained by increasing the perpendicular component or reducing the parallel component of the reflected wave polarization. An FDTD calculation is performed to obtain the scattered field. Projecting the resulting scattered field to the vector spherical harmonic basis, we show through multipole moments analysis that the suppression of backscattering non-MO field and the raise of the backscattered MO field can be achieved by subtle superposition of some optical modes. For the specific YIG particle system and the wavelength range chosen, the result shows that enhancement of MOKE up to 7.5[Formula: see text]mrad can be achieved.