scholarly journals A New Approach to Analytical Modeling of Mars’s Magnetic Field

Author(s):  
I.E. Stepanova ◽  
T.V. Gudkova ◽  
A.M. Salnikov ◽  
A.V. Batov
2021 ◽  
Author(s):  
Yury Belousov ◽  
Roberto Grimaudo ◽  
Antonino Messina ◽  
Agostino Migliore ◽  
Alessandro Sergi

2017 ◽  
Vol 31 (25) ◽  
pp. 1745001 ◽  
Author(s):  
Qiudong Guo ◽  
Peng Zhang ◽  
Lin Bo ◽  
Guibin Zeng ◽  
Dengqian Li ◽  
...  

With the rapid development of manufacturing technology of high temperature superconductive YB[Formula: see text]Cu3O[Formula: see text] YBCO materials and decreasing in cost of production, YBCO is marching into industrial areas with its good performances as source of high-magnetic field and rather low cost in reaching superconductivity. Based on analysis of the performance of high temperature superconductors YBCO and development of technology in superconductive magnetic separation both home and abroad, we propose a new approach of taking YBCO tape to make a solenoid as the source of a high magnetic field of magnetic separatior of ores. The paper also looks into the future of the YBCO high temperature superconductive magnetic separation from the perspective of technology and cost, as well as its applications in other industries.


2000 ◽  
Vol 18 (10) ◽  
pp. 1257-1262 ◽  
Author(s):  
A. V. Pavlov ◽  
T. Abe ◽  
K.-I. Oyama

Abstract. We present a comparison of the electron density and temperature behaviour in the ionosphere and plasmasphere measured by the Millstone Hill incoherent-scatter radar and the instruments on board of the EXOS-D satellite with numerical model calculations from a time-dependent mathematical model of the Earth's ionosphere and plasmasphere during the geomagnetically quiet and storm period on 20–30 January, 1993. We have evaluated the value of the additional heating rate that should be added to the normal photoelectron heating in the electron energy equation in the daytime plasmasphere region above 5000 km along the magnetic field line to explain the high electron temperature measured by the instruments on board of the EXOS-D satellite within the Millstone Hill magnetic field flux tube in the Northern Hemisphere. The additional heating brings the measured and modelled electron temperatures into agreement in the plasmasphere and into very large disagreement in the ionosphere if the classical electron heat flux along magnetic field line is used in the model. A new approach, based on a new effective electron thermal conductivity coefficient along the magnetic field line, is presented to model the electron temperature in the ionosphere and plasmasphere. This new approach leads to a heat flux which is less than that given by the classical Spitzer-Harm theory. The evaluated additional heating of electrons in the plasmasphere and the decrease of the thermal conductivity in the topside ionosphere and the greater part of the plasmasphere found for the first time here allow the model to accurately reproduce the electron temperatures observed by the instruments on board the EXOS-D satellite in the plasmasphere and the Millstone Hill incoherent-scatter radar in the ionosphere. The effects of the daytime additional plasmaspheric heating of electrons on the electron temperature and density are small at the F-region altitudes if the modified electron heat flux is used. The deviations from the Boltzmann distribution for the first five vibrational levels of N2(v) and O2(v) were calculated. The present study suggests that these deviations are not significant at the first vibrational levels of N2 and O2 and the second level of O2, and the calculated distributions of N2(v) and O2(v) are highly non-Boltzmann at vibrational levels v > 2. The resulting effect of N2(v > 0) and O2(v > 0) on NmF2 is the decrease of the calculated daytime NmF2 up to a factor of 1.5. The modelled electron temperature is very sensitive to the electron density, and this decrease in electron density results in the increase of the calculated daytime electron temperature up to about 580 K at the F2 peak altitude giving closer agreement between the measured and modelled electron temperatures. Both the daytime and night-time densities are not reproduced by the model without N2(v > 0) and O2(v > 0), and inclusion of vibrationally excited N2 and O2 brings the model and data into better agreement.Key words: Ionosphere (ionospheric disturbances; ionosphere-magnetosphere interactions; plasma temperature and density)  


2008 ◽  
Vol 54 (12) ◽  
pp. 1016-1022 ◽  
Author(s):  
Xiaoke Wang ◽  
Likun Liang ◽  
Tao Song ◽  
Longfei Wu

Magnetic particles are currently one of the most important materials in the industrial sector, where they have been widely used for biotechnological and biomedical applications. To investigate the effects of the imposed magnetic field on biomineralization in Magnetospirillum magneticum AMB-1 and to suggest a new approach that enhances formation of magnetosomes, cultures inoculated with either magnetic or nonmagnetic precultures were incubated under a sinusoidal magnetic field or geomagnetic field. The results showed that the sinusoidal magnetic field up-regulated mms6 expression in the cultures inoculated with magnetic cells, and magA, mms6, and mamA expression in the cultures inoculated with nonmagnetic cells. The applied sinusoidal magnetic field could block cell division, which could contribute to a decrease in the OD600 values and an increase in the coefficient of magnetism values of the cultures, which could mean that the percentage of mature magnetosome-containing bacteria was increased. The linearity of magnetosome chains was affected, but the number of magnetic particles in cells was increased when a sinusoidal magnetic field was applied to the cultures. The results imply that the variable intensity and orientation of the sinusoidal magnetic field resulted in magnetic pole conversion in the newly forming magnetic particles, which could affect the formation of magnetic crystals and the arrangement of the adjacent magnetosome.


2017 ◽  
Vol 20 (1) ◽  
pp. 014010 ◽  
Author(s):  
Yafeng BAI ◽  
Shiyi ZHOU ◽  
Yushan ZENG ◽  
Yihan LIANG ◽  
Rong QI ◽  
...  

1978 ◽  
Vol 19 (2) ◽  
pp. 201-225 ◽  
Author(s):  
M. J. Giles

A new approach to the problem of the radiation emitted from a localized external current source embedded in a magnetoplasma is described. It is argued that the calculation of the fields in the radiation zone can be substantially simplified by adopting at the outset a suitable parametrization of the dispersion surface. We illustrate the approach by calculating the far fields using the full expression for the dielectric tensor of a warm magnetized electron gas. In this case one can take the angle of rotation about the external magnetic field and the square of the refractive index as the curvilinear co-ordinates of the dispersion surface. The form of the surfaces of constant phase and the amplitudes of the emitted waves are described for each topologically different region of parameter space and their structures are related to the shapes of the refractive index surfaces. Attention is also drawn to the existence of locally cylindrical waves that can produce beams which are highly collimated in the direction of the external magnetic field.


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