In the present paper dependence of geomagnetic activity on the solar-wind plasma and interplanetary magnetic field (IMF) parameters has been studied. We have taken interplanetary solar wind data at the instant of Dst ...In the present paper dependence of geomagnetic activity on the solar-wind plasma and interplanetary magnetic field (IMF) parameters has been studied. We have taken interplanetary solar wind data at the instant of Dst minimum. Our study consists of 200 geomagnetic storms weighed by disturbance storm time (Dst) -50 nT, observed during solar cycle 23. The study suggests that the strength of the geomagnetic storm is strongly dependent on the total magnetic field Btotal. The correlation (-0.72) has been found reasonable. In perspective of previous studies, the strength of the geomagnetic storm is strongly dependent on the southward component (Bz) whereas in present study exposes that the correlation (0.22) is weak. This result indicates that solar wind southward magnetic field component Bz has significant growth particularly before the main phase of geomagnetic storm (not during the main phase). The present result implies that neither density nor temperature is significantly related to the variation of geomagnetic disturbance;rather the effects of the pressure and speed. However, a low plasma beta during highly geoeffective event seems to be an important criterion.展开更多
We present the spin polarized calculations on the new Zr2NiX (X = Al, Ga) alloys. Band structure analysis present them as half-metallic compounds with integral spin magnetic moment of 3 B following the general Slater-...We present the spin polarized calculations on the new Zr2NiX (X = Al, Ga) alloys. Band structure analysis present them as half-metallic compounds with integral spin magnetic moment of 3 B following the general Slater-Pauling rule. Thermal effects on some macroscopic properties using quasi-harmonic Debye model which considers the phononic effects, the effects of pressure and temperature are taken into account. The variations of the thermal expansion coefficient, Debye temperature, Gruneisen parameter and heat capacity for the compounds have been investigated for the first time. These thermodynamic properties may prove as a reference for their synthesis.展开更多
文摘In the present paper dependence of geomagnetic activity on the solar-wind plasma and interplanetary magnetic field (IMF) parameters has been studied. We have taken interplanetary solar wind data at the instant of Dst minimum. Our study consists of 200 geomagnetic storms weighed by disturbance storm time (Dst) -50 nT, observed during solar cycle 23. The study suggests that the strength of the geomagnetic storm is strongly dependent on the total magnetic field Btotal. The correlation (-0.72) has been found reasonable. In perspective of previous studies, the strength of the geomagnetic storm is strongly dependent on the southward component (Bz) whereas in present study exposes that the correlation (0.22) is weak. This result indicates that solar wind southward magnetic field component Bz has significant growth particularly before the main phase of geomagnetic storm (not during the main phase). The present result implies that neither density nor temperature is significantly related to the variation of geomagnetic disturbance;rather the effects of the pressure and speed. However, a low plasma beta during highly geoeffective event seems to be an important criterion.
文摘We present the spin polarized calculations on the new Zr2NiX (X = Al, Ga) alloys. Band structure analysis present them as half-metallic compounds with integral spin magnetic moment of 3 B following the general Slater-Pauling rule. Thermal effects on some macroscopic properties using quasi-harmonic Debye model which considers the phononic effects, the effects of pressure and temperature are taken into account. The variations of the thermal expansion coefficient, Debye temperature, Gruneisen parameter and heat capacity for the compounds have been investigated for the first time. These thermodynamic properties may prove as a reference for their synthesis.
