FURTHER OBSERVATIONS OF THE HORIZONTAL MOVEMENTS OF AURORA

1960 ◽  
Vol 38 (10) ◽  
pp. 1366-1375 ◽  
Author(s):  
J. A. Kim ◽  
B. W. Currie
Keyword(s):  
Magnetic Field ◽  
Seasonal Variation ◽  
Magnetic Field Intensity ◽  
Geomagnetic Latitude ◽  
Auroral Zone ◽  
The North ◽  
Significant Seasonal Variation ◽  
Positive Correlations ◽  
The Magnetic Field ◽  
East West

A previous paper showed that systematic motions of aurora parallel and normal to the geomagnetic meridians could be deduced from successions of all-sky camera photographs. More reliable deductions which are based on a much larger number of observations, including some from a station inside the auroral zone, are reported in this paper. Both southward and northward speeds increase with geomagnetic latitude to the auroral zone where they become constant, or even decrease slightly, before continuing to increase inside the auroral zone. A seasonal variation of north–south speeds does not appear to exist. A diurnal variation of north–south speeds, dependent on geomagnetic latitude, is evident, the speeds decreasing to a minimum during the morning hours to the south of the auroral zone and increasing to a maximum during the same hours to the north of the zone. Large positive correlations exist between north–south speeds and departures of the magnetic field intensity from normal. East–west speeds either decrease or remain constant with increasing geomagnetic latitude. A significant seasonal variation of east–west speeds is not evident. Eastward speeds are at a maximum between 03 and 04 hours L.M.T., and are associated with negative magnetic bays; westward speeds, between 21 and 22 hours L.M.T., and are associated with positive magnetic bays.

scholarly journals The structure and dynamics of a large-scale plasmoid generated by fast reconnection in the geomagnetic tail

2011 ◽  
Vol 29 (1) ◽  
pp. 147-156 ◽  
Author(s):  
M. Ugai
Keyword(s):  
Magnetic Field ◽  
Current Sheet ◽  
Large Scale ◽  
Field Component ◽  
The North ◽  
Reconnection Region ◽  
Field Lines ◽  
The Magnetic Field ◽  
East West ◽  
Fast Reconnection

Abstract. As a sequence of Ugai (2010b), the present paper studies in detail the structure and dynamics of large-scale (principal) plasmoid, generated by the fast reconnection evolution in a sheared current sheet with no initial northward field component. The overall plasmoid domain is divided into the plasmoid reconnection region P and the plasmoid core region C. In the region P, the magnetized plasma with reconnected field lines are accumulated, whereas in the region C, the plasma, which was intially embedded in the current sheet and has been ejected away by the reconnection jet, is compressed and accumulated. In the presence of the sheared magnetic field in the east-west direction in the current sheet, the upper and lower parts of the reconnection region P are inversely shifted in the east-west directions. Accordingly, the plasmoid core region C with the accumulated sheared field lines is bent in the north-south direction just ahead of the plasmoid center x=XC, causing the magnetic field component in the north-south direction, whose sign is always opposite to that of the reconnected field lines. Therefore, independently of the sign of the initial sheared field, the magnetic field component Bz in the north-south direction has the definite bipolar profile around XC along the x-axis. At x=XC, the sheared field component has the peak value, and as the sheared fields accumulated in the region C become larger, the bipolar field profile becomes more distinct.

Detection of a change in the North-South ratio of count rates of particles of high-energy cosmic rays during a change in the polarity of the magnetic field of the Sun

JETP Letters ◽  
2015 ◽  
Vol 101 (4) ◽  
pp. 228-231
Author(s):  
A. V. Karelin ◽  
O. Adriani ◽  
G. C. Barbarino ◽  
G. A. Bazilevskaya ◽  
R. Bellotti ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Cosmic Rays ◽  
High Energy ◽  
The Sun ◽  
High Energy Cosmic Rays ◽  
The North ◽  
The Magnetic Field

scholarly journals Magnetotaxis as a Means for Nanofabrication

2014 ◽  
Vol 23 (01n02) ◽  
pp. 1450008
Author(s):  
Isaac Macwan ◽  
Zihe Zhao ◽  
Omar Sobh ◽  
Jinnque Rho ◽  
Ausif Mahmood ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Geomagnetic Field ◽  
Semiconductor Manufacturing ◽  
Magnetic Field Intensity ◽  
Magnetotactic Bacteria ◽  
Semiconductor Substrate ◽  
Field Lines ◽  
A Chain ◽  
Magnetospirillum Magneticum ◽  
The Magnetic Field

Magnetotactic bacteria (MTB), discovered in early 1970s contain single-domain crystals of magnetite ( Fe 3 O 4) called magnetosomes that tend to form a chain like structure from the proximal to the distal pole along the long axis of the cell. The ability of these bacteria to sense the magnetic field for displacement, also called magnetotaxis, arises from the magnetic dipole moment of this chain of magnetosomes. In aquatic habitats, these organisms sense the geomagnetic field and traverse the oxic-anoxic interface for optimal oxygen concentration along the field lines. Here we report an elegant use of MTB where magnetotaxis of Magnetospirillum magneticum (classified as AMB-1) could be utilized for controlled navigation over a semiconductor substrate for selective deposition. We examined 50mm long coils made out of 18AWG and 20AWG copper conductors having diameters of 5mm, 10mm and 20mm for magnetic field intensity and heat generation. Based on the COMSOL simulations and experimental data, it is recognized that a compound semiconductor manufacturing technology involving bacterial carriers and carbon-based materials such as graphene and carbon nanotubes would be a desirable choice in the future.

A two-dimensional analysis of the compressible flow near a reconnection site at the dayside magnetopause

2007 ◽  
Vol 73 (1) ◽  
pp. 89-115 ◽  
Author(s):  
LARS G. WESTERBERG ◽  
HANS O. ÅKERSTEDT
Keyword(s):  
Magnetic Field ◽  
Transition Layer ◽  
Alfven Wave ◽  
The North ◽  
Dayside Magnetopause ◽  
Reconnection Site ◽  
Ideal Magnetohydrodynamic ◽  
North And South ◽  
Magnetic Field Variations ◽  
The Magnetic Field

Abstract.A compressible model of the magnetosheath plasma flow is considered. Magnetic reconnection is assumed to occur in a region stretching from the sub-Solar point to the north. Two locations of the reconnection site are treated: two and four Earth radii from the sub-Solar point, respectively. By treating the transition layer as very thin, we solve the governing equations approximately using the method of matched asymptotic expansions. The behavior of the magnetic field and the plasma velocity close to a reconnection site during the transition from the magnetosheath to the magnetosphere is investigated. We also obtain the development of the transition layer thickness north and south of the reconnection point. The magnetopause transition layer is represented by a large-amplitude Alfvén wave implying that the density is approximately the same across the magnetopause boundary. In order to match the solutions we consider a compressible ideal magnetohydrodynamic model describing density, velocity and magnetic field variations along the outer magnetopause boundary. We also compare the analytical results with solutions from a numerical simulation. The compressible effects on the structure of the magnetic field and the total velocity evolution are visible but not dramatic. It is shown that the transition layer north of the reconnection point is thinner than to the south. The effect is stronger for reconnection at higher latitudes.

Tunable amplified spontaneous emission based on liquid magnetically responsive photonic crystals

2019 ◽  
Vol 7 (13) ◽  
pp. 3740-3743 ◽  
Author(s):  
Ying Li ◽  
Yue Long ◽  
Guoqiang Yang ◽  
Chen-Ho Tung ◽  
Kai Song
Keyword(s):  
Magnetic Field ◽  
Photonic Crystals ◽  
Spontaneous Emission ◽  
Field Intensity ◽  
Magnetic Field Intensity ◽  
Amplified Spontaneous Emission ◽  
The Magnetic Field

The wavelength of amplified spontaneous emission based on liquid magnetically responsive photonic crystals can be tuned by simply changing the magnetic field intensity.

scholarly journals A Novel Method for Improving Low-Temperature Flotation Performance of Nonpolar Oil in the Molybdenite Flotation

Minerals ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 609 ◽  
Author(s):  
Wan ◽  
Qu ◽  
Li ◽  
He ◽  
Bu ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Surface Tension ◽  
Low Temperature ◽  
Interfacial Tension ◽  
Field Intensity ◽  
Magnetic Field Intensity ◽  
Maximum Surface ◽  
Flotation Recovery ◽  
Flotation Performance ◽  
The Magnetic Field

Nonpolar hydrocarbon oil (NHO) is one of the most extensively used collectors in the flotation of molybdenite due to its excellent selectivity. However, NHO has low sensibility at pulp temperature. At low temperatures (<283 K), although more kerosene is used, the recovery of molybdenite flotation is still lower than at room temperature. In this study, magnetizing treatment, which is an efficient, low-cost, innovative, and environmentally friendly emulsification method, was used to improve the flotation performance of NHO in low-temperature molybdenite flotation. The test results showed that, compared with unmagnetized kerosene (UMK), the optimum dosage of magnetized kerosene (MK) could be reduced by 11% at 298 K. At the same dosage of kerosene, the flotation recovery of MK was 3% higher than UMK at 278 K. The surface tension measurement results showed that the surface tension of MK rose periodically as the magnetic field intensity increased, and there was a maximum surface tension within each period. Further, the magnetic field intensity had the maximum flotation recovery of molybdenite at the maximum surface tension of MK. Combined with the analysis based on the Girifalco–Good theory and the static drop volume method of interfacial tension, the interfacial tension of kerosene–water was shown to decrease with the increase of the surface tension of kerosene. This finding indicates that the dispersibility of kerosene in pulp could be improved by reducing the size of oil droplets, thereby improving the molybdenite flotation recovery of kerosene at low-temperature pulp. It is helpful to improve the flotation recovery of molybdenite using NHO as a collector for low-temperature pulp (<283 K).

scholarly journals Optical Birefringence Growth Driven by Magnetic Field in Liquids: The Case of Dibutyl Phosphate/Propylamine System

2019 ◽  
Vol 10 (1) ◽  
pp. 164 ◽  
Author(s):  
Mikolaj Pochylski ◽  
Domenico Lombardo ◽  
Pietro Calandra
Keyword(s):  
Magnetic Field ◽  
Self Assembly ◽  
Magnetic Field Intensity ◽  
Magnetic Energy ◽  
Molar Ratio ◽  
Molecular Liquids ◽  
Microscopic Scale ◽  
Intensity Response ◽  
Soft Particles ◽  
The Magnetic Field

Magnetically-induced birefringence is usually low in molecular liquids owing to the low magnetic energy of molecules with respect to the thermal one. Despite this, it has been found that a mixture of dibutyl phosphate and propylamine at propylamine molar ratio (X) around 0.33 surprisingly gives an intense effect (∆n/λ ≈ −0.1 at 1 Tesla). In this paper the time- and intensity- response to the magnetic field of such mixture have been studied. It was found that the reaction to the magnetic field is unusually slow (from several minutes to hours) depending of the magnetic field intensity. On the basis of the data, the model of orientable dipoles dispersed in a matrix enables to interpret the magnetic field-induced self-assembly in terms of soft molecules-based nanostructures. The analogy with systems made of magnetically polarizable (solid or soft) particles dispersed in liquid carrier allows understanding, at the microscopic scale, the molecular origin and the supra-molecular dynamics involved in the observed behavior. The data present a novel phenomenon in liquid phase where the progressive building up/change of ordered and strongly interacting amphiphiles is driven by the magnetic field.

AN ELECTROMAGNETIC INTERPRETATION PROBLEM IN GEOPHYSICS

Geophysics ◽  
1951 ◽  
Vol 16 (3) ◽  
pp. 431-449 ◽  
Author(s):  
L. B. Slichter
Keyword(s):  
Magnetic Field ◽  
Electrical Properties ◽  
Magnetic Field Intensity ◽  
Vertical Component ◽  
Single Frequency ◽  
Magnetic Intensity ◽  
Conductivity Function ◽  
The Magnetic Field ◽  
Surface Observations ◽  
Interpretation Problem

An interpretation problem in electromagnetic prospecting is discussed. A flat earth in which the three electrical properties of material vary only with depth is subjected to an alternating inducing field produced by a dipole above the surface with axis perpendicular to the surface. Observations of the horizontal or of the vertical component of the magnetic intensity at the ground’s surface are supposed to be available at all distances. From these observations solutions for the three unknown functions are developed. When the magnetic permeability is variable, the solutions for the permeability and dielectric functions require observations at two different frequencies. The conductivity function may be found from observations at a single frequency. It is shown that the horizontal and vertical components of the magnetic field intensity are mutually dependent in the region above the ground’s surface; and formulae independent of the ground’s characteristics are deduced for expressing [Formula: see text] in terms of [Formula: see text], and vice‐versa. Here [Formula: see text] denotes a plane coincident with or above and parallel to, the earth’s surface.

Viscosity of Potassium Dihydrogen Phosphate Aqueous Solution within Magnetic Field

2017 ◽  
Vol 898 ◽  
pp. 1783-1786
Author(s):  
Lei Zhang ◽  
Yi Su ◽  
Yu Lin Wu ◽  
Yao Liu ◽  
Yong Wang ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Aqueous Solution ◽  
Field Intensity ◽  
Magnetic Field Intensity ◽  
Extreme Values ◽  
Potassium Dihydrogen Phosphate ◽  
Experimental Results ◽  
Dihydrogen Phosphate ◽  
Potassium Dihydrogen ◽  
The Magnetic Field

The viscosity of potassium dihydrogen phosphate, KH2PO4 (KDP), aqueous solution within magnetic field was studied. Experimental results showed that, the viscosity of saturated KDP solution exhibited multiple extreme values when the magnetic field intensity increased from 0 Gs to 2250 Gs. Influences of the magnetic field intensity on the viscosity of KDP solution were very complicated. It’s concerned with the temperature and the concentration of solution. As the KDP was produced from aqueous solution within magnetic field, the temperature and the concentration of solution also needed to be carefully controlled. Magnetic field with intensity values of 300 Gs, 600 Gs and 1800 Gs, all have the strong effects on the structures of KDP aqueous solution.

Microstructure and Properties under Alternating Magnetism after Hot Rolling

2014 ◽  
Vol 1004-1005 ◽  
pp. 1256-1259
Author(s):  
Shen Bai Zheng ◽  
Shi Jie Liu ◽  
Hong Bin Li ◽  
Bin Feng ◽  
Xue Song Hui
Keyword(s):  
Magnetic Field ◽  
Carbon Steel ◽  
Cold Rolling ◽  
Grain Growth ◽  
Hot Rolling ◽  
Magnetic Field Intensity ◽  
Raw Materials ◽  
Low Carbon Steel ◽  
Low Carbon ◽  
The Magnetic Field

The austenite steel after rolling was radiated by the alternating magnetism, and the effects that alternating magnetic on the austenite transition was studied. The result shows that the alternating magnetism promotes the austenitic grain growth of low carbon steel. If the magnetic field intensity is increased, it could provide better performance of raw materials to cold rolling processing.

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