Calculation of magnetic field-induced current densities for humans from EAS countertop activation/deactivation devices that use ferromagnetic cores

2005 ◽  
Vol 50 (2) ◽  
pp. 373-385 ◽  
Author(s):  
Qingxiang Li ◽  
Om P Gandhi
Keyword(s):  
Magnetic Field ◽  
Induced Current ◽  
Current Densities

Schwingung eines Plasmazylinders in einem äußeren Magnetfeld

1957 ◽  
Vol 12 (10) ◽  
pp. 815-821 ◽  
Author(s):  
K. Körper
Keyword(s):  
Magnetic Field ◽  
Axial Direction ◽  
Homogeneous Magnetic Field ◽  
Index Of Refraction ◽  
Infinite Length ◽  
Induced Current ◽  
Resonance Frequencies ◽  
Small Density ◽  
Basic Equations ◽  
Hydromagnetic Waves

Es werden die durch elektromagnetische Strahlung erregten Schwingungen einer kreiszylindrischen, homogenen, unendlich langen, einem homogenen axialen statischen Magnetfeld ausgesetzten Plasmasäule behandelt. Die zwei möglichen Schwingungstypen lassen sich durch die Richtung des im Plasma induzierten Stromes relativ zum Magnetfeld unterscheiden. Bei Strömen parallel zum Magnetfeld werden die Schwingungen durch den EccLEsschen Brechungsindex charakterisiert. Ströme senkrecht zum Magnetfeld liefern einen Brechungsindex, der zwei von der Teilchendichte des Plasmas und dem statischen Magnetfeld abhängige Resonanzfrequenzen (Ionenresonanz, Elektronenresonanz) besitzt. Dieser Brechungsindex geht für kleine Frequenzen in den für magnetohydrodynamische Wellen über. — Aus den Grundgleichungen wird der Energiesatz des Plasmas hergeleitet; er enthält neben der elektromagnetischen Strahlungsleistung, der JOULESchen Wärme und den Zeitableitungen der elektrischen und magnetischen Energiedichte noch die der kinetischen Energien der Elektronen und Ionen.The oscillations of a plasma cylinder of infinite length have been analyzed. The plasma is assumed to be homogeneous and to be exposed to a static homogeneous magnetic field in axial direction. There are two different types of oscillations. In one case the induced current is parallel to the magnetic field, and is therefore not influenced by it. In the other case where the induced current is perpendicular to the field two resonance frequencies exist. In the limit of small density and high magnetic field these are the gyrofrequencies of the iones and the electrons. The index of refraction for both types in the limit of small frequencies is that of the “hydromagnetic waves”. — From the basic equations the energy conservation theorem is derived. Besides the usual terms giving the electromagnetic radiation, JOULE’S losses, the electromagnetic energy density, it contains the kinetic energy of the ions and electrons of the plasma.

scholarly journals Non-magnetic generating electricity

2021 ◽  
Author(s):  
Shuai Yang
Keyword(s):  
Magnetic Field ◽  
Magnetic Flux ◽  
Electric Field ◽  
Induced Current ◽  
Current Generation ◽  
Scientific Cognition ◽  
The Past ◽  
Directional Movement ◽  
Voltage Generation ◽  
The Magnetic Field

Abstract In the past scientific cognition, changes in the magnetic field produce electric field, so when there is current and voltage generation, need to have a change in magnetic flux, However, in the process of studying the nature of magnetization, we found that the microscopic formation of a magnetic field is the directional movement of positive and negative charges, under the guidance of this theory, we use other methods, realize the separation of positive and negative charges, observation of induced current generation, this can be used as another way to generate electricity.

scholarly journals Statistical analysis of the dependence of large-scale Birkeland currents on solar wind parameters

2010 ◽  
Vol 28 (2) ◽  
pp. 515-530 ◽  
Author(s):  
H. Korth ◽  
B. J. Anderson ◽  
C. L. Waters
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Mach Number ◽  
Electric Field ◽  
Large Scale ◽  
Dynamic Pressure ◽  
Dominant Factor ◽  
Total Current ◽  
Current Densities ◽  
Birkeland Currents

Abstract. The spatial distributions of large-scale field-aligned Birkeland currents have been derived using magnetic field data obtained from the Iridium constellation of satellites from February 1999 to December 2007. From this database, we selected intervals that had at least 45% overlap in the large-scale currents between successive hours. The consistency in the current distributions is taken to indicate stability of the large-scale magnetosphere–ionosphere system to within the spatial and temporal resolution of the Iridium observations. The resulting data set of about 1500 two-hour intervals (4% of the data) was sorted first by the interplanetary magnetic field (IMF) GSM clock angle (arctan(By/Bz)) since this governs the spatial morphology of the currents. The Birkeland current densities were then corrected for variations in EUV-produced ionospheric conductance by normalizing the current densities to those occurring for 0° dipole tilt. To determine the dependence of the currents on other solar wind variables for a given IMF clock angle, the data were then sorted sequentially by the following parameters: the solar wind electric field in the plane normal to the Earth–Sun line, Eyz; the solar wind ram pressure; and the solar wind Alfvén Mach number. The solar wind electric field is the dominant factor determining the Birkeland current intensities. The currents shift toward noon and expand equatorward with increasing solar wind electric field. The total current increases by 0.8 MA per mV m−1 increase in Eyz for southward IMF, while for northward IMF it is nearly independent of the electric field, increasing by only 0.1 MA per mV m−1 increase in Eyz. The dependence on solar wind pressure is comparatively modest. After correcting for the solar dynamo dependencies in intensity and distribution, the total current intensity increases with solar wind dynamic pressure by 0.4 MA/nPa for southward IMF. Normalizing the Birkeland current densities to both the median solar wind electric field and dynamic pressure effects, we find no significant dependence of the Birkeland currents on solar wind Alfvén Mach number.

Electrode conduction processes in air plasmas

1962 ◽  
Vol 13 (3) ◽  
pp. 465-477 ◽  
Author(s):  
D. W. George ◽  
H. K. Messerle
Keyword(s):  
Magnetic Field ◽  
Shock Tube ◽  
Current Flow ◽  
Electronic Conductivity ◽  
The Other ◽  
High Current ◽  
Air Plasma ◽  
Air Plasmas ◽  
Current Densities

Using an electrically driven shock tube with initial pressures of 0.1 to 1.0 mm Hg and shock speeds of about Mach 12 to 15, the resistance of an air plasma between two parallel probes has been measured by two different techniques and the results compared. In one, external voltages of from 0 to 100 V were applied to the probes and in the other, electromagnetically induced voltages of from 0 to 25 V were produced by the plasma's motion in a magnetic field of up to 3500 G. In either case the resistance was found to decrease as the current flow increased and was consistent with the equilibrium electronic conductivity of the air plasma at high current densities.

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