Overshoot dependence on the cross-shock potential

Coherent downstream oscillations of the magnetic field in shocks are produced due to the coherent ion gyration and quasiperiodic variations of the ion pressure. The amplitude and the positions of the pressure maxima and minima depend on the cross-shock potential and upstream ion temperature. Two critical cross-shock potentials are defined: the critical gyration potential (CGP), which separates the cases of increase or decrease in the component of the velocity of the distribution center along the shock normal, and the critical reflection potential (CRP), above which ion reflection becomes significant. In a weak, very low upstream kinetic-to-magnetic pressure ratio, β, the shocks' CRP exceeds the CGP. For potentials below the CGP, the first downstream maximum of the magnetic field is shifted farther downstream and is larger than the second maximum. For higher potentials, the first maximum occurs just behind the ramp and is lower than the second maximum. With the increase in the upstream temperature, the CGP exceeds the CRP. For potentials below the CRP, the effects of ion reflection are negligible and the shock profile is similar to that of very low-β shocks. If the potential exceeds the CRP, ion reflection is significant, the magnetic field increase toward the overshoot becomes steeper, and the largest peak occurs at the downstream edge of the ramp.

Overshoot dependence on the cross-shock potential

Coherent downstream oscillations of the magnetic field in shocks are produced due to the coherent ion gyration and quasi-periodic variations of the ion pressure. The amplitude and the positions of the pressure maxima and minima depend on the cross-shock potential and upstream ion temperature. Two critical potentials are defined: the critical gyration potential (CGP) which separates the cases of increase or decrease of the normal velocity of the distribution center, and the critical reflection potential (CRP) above which ion reflection becomes significant. In weak very low β shocks CRP exceeds CGP. For potentials below CGP the first downstream maximum of the magnetic field is shifted farther downstream and is larger than the second one. For higher potentials the first maximum occurs just behind the ramp and is lower than the second one. With the increase of the upstream temperature CGP exceeds the CRP. For potentials below CRP the effects of ion reflection are negligible and the shock profile is similar to that of very low β shocks. If the potential exceeds CRP ion reflection is significant, the magnetic field increase toward the overshoot becomes steeper, and the largest peak occurs at the downstream edge of the ramp.

The Magnetic Microstructure of YIG / GGG Films: Mossbauer Studies in the External Magnetic Fields

The Mossbauer studies of yttrium iron garnet (YIG) films grown on the gadolinium gallium garnet (GGG) substrate was realized for different films thickness (2.85 and 5.42 mm) at the applied external magnetic field. It is shown that the main changes in the magnetic microstructure of YIG/GGG films are occurred at magnetic field value up to 2.20 kOe. The changes of the hyperfine magnetic fields on the iron nuclei have been investigated and its isotropic component was analyzed. It was determined that the domain structure changes (in particular, the domains width enlarging) under the applied magnetic field increase with the film thickness decreasing.

Effect of Variable Viscosity on MHD Inclined Arterial Blood Flow with Chemical Reaction

In this paper, we present the mathematical study of heat and mass transfer effects on an arterial blood flow under the influence of an applied magnetic field with chemical reaction. A case of mild stenosis is considered in a non-tapered artery which is inclined at an angle γ from the axis. The variable viscosity of the blood is considered varying with the hematocrit ratio. Governing non-linear differential equations have been solved by using an analytical scheme, homotopy perturbation method to obtain the solution for the velocity, temperature and concentration profiles of the blood flow. For having an adequate insight to blood flow behavior through a stenosed artery, graphs have been plotted for wall shear stress, velocity, temperature and concentration profiles with varying values of the applied magnetic field, chemical reaction parameter and porosity parameter. The results show that in an inclined artery, the magnitude of the wall shear stress at stenosis throat increases as values of the applied magnetic field increase while it reduces as the values of both the chemical reaction and porosity parameters increase. Contour plots have been plotted to show the variations of the velocity profile of blood flow as the values of the height of the stenosis as well as the influence of the applied magnetic field increase.

Magnetic depression and electron transport in an ion-scale flux rope associated with Kelvin–Helmholtz waves

We report an ion-scale magnetic flux rope (the size of the flux rope is ∼ 8.5 ion inertial lengths) at the trailing edge of Kelvin–Helmholtz (KH) waves observed by the Magnetospheric Multiscale (MMS) mission on 27 September 2016, which is likely generated by multiple X-line reconnection. The currents of this flux rope are highly filamentary: in the central flux rope, the current flows are mainly parallel to the magnetic field, supporting a local magnetic field increase at about 7 nT, while at the edges the current filaments are predominantly along the antiparallel direction, which induce an opposing field that causes a significant magnetic depression along the axis direction (> 20 nT), meaning the overall magnetic field of this flux rope is depressed compared to the ambient magnetic field. Thus, this flux rope, accompanied by the plasma thermal pressure enhancement in the center, is referred to as a crater type. Intense lower hybrid drift waves (LHDWs) are found at the magnetospheric edge of the flux rope, and the wave potential is estimated to be ∼ 17 % of the electron temperature. Though LHDWs may be stabilized by the mechanism of electron resonance broadening, these waves could still effectively enable diffusive electron transports in the cross-field direction, corresponding to a local density dip. This indicates LHDWs could play important roles in the evolution of crater flux ropes. Keywords. Magnetospheric physics (magnetopause, cusp, and boundary layers; solar wind–magnetosphere interactions)

Flux pile-up and plasma depletion at the high latitude dayside magnetopause during southward interplanetary magnetic field: a cluster event study

An event of strong flux pile-up and plasma depletion at the high latitude magnetopause tailward of the cusp has been analyzed based on observations by the suite of Cluster spacecraft. The multi-satellite analysis facilitates the separation of temporal and spatial features and provides a direct estimate for the strength of the plasma depletion layer for this event. A doubling of the magnetic field strength and a forty percent reduction of the density are found. Our analysis shows that roughly half of the total magnetic field increase occurs within 0.6 RE of the magnetopause and another quarter within a distance of 1.2 RE. In addition, the plasma depletion signatures exhibit temporal variations which we relate to magnetopause dynamics. Keywords. Magnetospheric physics (Magnetopause, Cusp and boundary layers; Magnetosheath; Solar windmagnetosphere interactions)

ELECTRONIC TRANSPORT PROPERTIES FOR THE ULTRAPURE SINGLE CRYSTALS OF THE TRANSITION METALS UNDER CONDITIONS OF THE STRONG STATIC SKIN EFFECT AT HIGH CURRENT DENSITIES

The electronic transport properties for the ultrapure single crystals of the transition metals are examined under conditions of the strong electron-surface scattering. In this case the static skin effect can be observed. Under these conditions some anomalies in the electronic properties take place. They are the gigantic growth of the magnetoresistivity with magnetic field increase, the strong dependence of the magnetoresistivity and Hall voltage on the electron-surface interaction, the appearance of the nonlinear current-voltage characteristics in metals. Some cryogenic devices based on the peculiarities of the electronic properties of the ultrapure metal crystals can be created.