The effects of a shear flow on nonlinear evolutions of double tearing mode in Hall magnetohydrodynamics

The effects of a shear flow on nonlinear evolution of double tearing mode in Hall magnetohydrodynamics are investigated. The parallel shear flow displays a suppressing effect on the double tearing mode. Due to the effect of the shear flow, the relative displacements between the magnetic islands are changed, and therefore their mutual interactions become weak. Furthermore, the nonlinear impulsive growth phase of the double tearing mode is delayed with increasing the shear flow velocity. When the magnetic islands are pushing against each other, the width of current sheets decreases drastically, and therefore the Hall effects are dominant and the magnetic reconnection enhances greatly.     

Searching for high-frequency gravitational waves with a ground high alternating magnetic field

正Recently,with the precise laser interferometers the LIGOVirgo collaboration[1-4]has realized the direct detection of the GWs,by probing their minute mechanical displacements.The peak strains of the detected GWs are at the order of 10-21and their frequencies are in the low-and intermediate frequency band,i.e.,dozens and hundreds of Hertz.Given the GWs could exist at any frequency[5,6],in principle,probing the GWs in the wider bands[7,8],typically the high frequency GWs expected by a series of models for cosmology     

Utilization of Electromagnetic Detector for Selection and Detection of High-Frequency Relic Gravitational Waves

It is shown that the coupling system between fractal membranes and a Gaussian beam passing through a static magnetic field has strong selection capability for the stochastic relic gravitational wave （GW） background. The relic GW components propagating along the positive direction of the symmetrical axis of the Gaussian beam might generate an optimal electromagnetic perturbation, while the perturbation produced by the relic GW components propagating along the negative and perpendicular directions to the symmetrical axis will be much less than the former, and the influence of the random fluctuation of the relic GWs to such effect can be neglected. The high-frequency relic GWs satisfying the parameters requirement （h - 10^-31 or larger）, frequency resonance and “direction coupling”, in principle, would be selectable and measurable in seconds.