A Faraday’s law paradox

2021 ◽  
Vol 57 (1) ◽  
pp. 013003
Author(s):  
Rod Cross
Keyword(s):  
Magnetic Field ◽  
Voltage Drop ◽  
Potential Difference ◽  
Measured Voltage ◽  
Faraday’S Law

Abstract The voltage drop or potential difference across a resistor is easily measured with a voltmeter. However, if the loop formed by the resistor, the connecting leads, and the voltmeter surrounds a changing magnetic field then the measured voltage drop will be different. This result can lead to a paradox when using Faraday’s law.

A Circular Magneto-Hydrodynamic (MHD) Micropump With Electrolyte Solution

2004 ◽  
Author(s):  
Weidong Shen
Keyword(s):  
Magnetic Field ◽  
Cross Section ◽  
Closed Loop ◽  
Pressure Head ◽  
Electrolyte Solutions ◽  
Electrolyte Composition ◽  
Potential Difference ◽  
Copper Electrodes ◽  
Straight Conduit ◽  
The Magnetic Field

Linear and circular magneto-hydrodynamic (MHD) micro-pumps that operate with electrolyte solutions were studied experimentally. Each pump consisted of a conduit with a square cross-section. The linear pump consisted of a straight conduit with its inlet and an outlet subjected to different pressures. The circular pump consisted of a conduit bent into a loop. Copper electrodes were aligned along the two opposite walls of the conduits. Experiments were carried out with various electrolyte solutions such as NaCl, FeCl2/FeCl3, and CuSO4 at various concentrations. The device was placed in a uniform magnetic field and a potential difference was applied across the electrodes. The resulting current interacted with the magnetic field to produce a Lorenz force that propelled the liquid. The electric current and the flow rate were measured as functions of the imposed potential difference across the electrodes, the electrolyte composition and concentration, and the adverse pressure head. The feasibility of using the closed-loop MHD pump to transfer heat from a heat source to a heat sink was also explored.

Considerations of the effect of space-charge in the magnetron

1940 ◽  
Vol 36 (1) ◽  
pp. 94-100 ◽  
Author(s):  
E. B. Moullin
Keyword(s):  
Magnetic Field ◽  
Space Charge ◽  
Cylindrical Symmetry ◽  
Potential Difference ◽  
Anode Current ◽  
Pronounced Decrease ◽  
Field Parallel ◽  
Image Position ◽  
The Magnetic Field

When a diode thermionic tube, having cylindrical symmetry, is placed in a magnetic field parallel to its axis it is commonly called a magnetron. If there is a given potential difference between the anode and cathode of the tube, and if the magnetic field is steadily increased, a sharp and pronounced decrease of anode current occurs when the field reaches a certain value. It is easy to show that, if electrons leave without velocity from a cathode of radius b, they will just graze a concentric anode of radius a at potential V when the magnetic field H has the value given by

scholarly journals Proposed Parameters for a Circular Particle Accelerator for Proton Beam Therapy Obtained by Genetic Algorithm

2019 ◽  
Vol 7 (2A) ◽  
Author(s):  
Gustavo Lobato Campos ◽  
Tarcísio P. R. Campos
Keyword(s):  
Magnetic Field ◽  
Genetic Algorithm ◽  
Genetic Algorithms ◽  
Radiation Therapy ◽  
Proton Beam ◽  
Resonant Cavity ◽  
Proton Beam Therapy ◽  
Particle Accelerator ◽  
Potential Difference ◽  
Circular Particle

This paper brings to light optimized proposal for a circular particle accelerator for proton beam therapy purposes (named as ACPT). The methodology applied is based on computational metaheuristics based on genetic algorithms (GA) were used to obtain optimized parameters of the equipment. Some fundamental concepts in the metaheuristics developed in Matlab® software will be presented. Four parameters were considered for the proposed modeling for the equipment, being: potential difference, magnetic field, length and radius of the resonant cavity. As result, this article showed optimized parameters for two ACPT, one of them used for ocular radiation therapy, as well some parameters that will allow teletherapy, called in order ACPT – 65 and ACPT – 250, obtained through metaheuristics based in GA.

Study on Faraday's Law for the Non-uniform Magnetic Field Produced by a Permanent Magnet

2017 ◽  
Vol 67 (6) ◽  
pp. 725-732
Author(s):  
Mun-Ho KWON ◽  
Myung-Kyu KU ◽  
Jaeyeon SI ◽  
Ho-Meoyng CHOI*
Keyword(s):  
Magnetic Field ◽  
Permanent Magnet ◽  
Uniform Magnetic Field ◽  
Faraday’S Law

scholarly journals Mapping of steady-state electric fields and convective drifts in geomagnetic fields – Part 2: The IGRF

2016 ◽  
Vol 34 (1) ◽  
pp. 67-73 ◽  
Author(s):  
A. D. M. Walker
Keyword(s):  
Magnetic Field ◽  
Electric Field ◽  
Field Line ◽  
Electric Fields ◽  
Rate Of Change ◽  
International Geomagnetic Reference Field ◽  
First Order ◽  
Faraday’S Law ◽  
Geomagnetic Fields ◽  
Field Lines

Abstract. A method of mapping electric fields along geomagnetic field lines is applied to the IGRF (International Geomagnetic Reference Field) model. The method involves integrating additional sets of first order differential equations simultaneously with those for tracing a magnetic field line. These provide a measure of the rate of change of the separation of two magnetic field lines separated by an infinitesimal amount. From the results of the integration Faraday's law is used to compute the electric field as a function of position along the field line. Examples of computations from a software package developed to implement the method are presented. This is expected to be of use in conjugate studies of magnetospheric phenomena such as SuperDARN (Super Dual Auroral Radar) observations of convection in conjugate hemispheres, or comparison of satellite electric field observations with fields measured in the ionosphere.

scholarly journals Ion dynamics in magnetosonic shocks front

2018 ◽  
Vol 4 (4) ◽  
pp. 23-31 ◽  
Author(s):  
Геннадий Кичигин ◽  
Gennadiy Kichigin
Keyword(s):  
Magnetic Field ◽  
Shock Front ◽  
Small Angle ◽  
Critical Angle ◽  
Field Vector ◽  
Potential Difference ◽  
Magnetic Field Vector ◽  
Ion Dynamics ◽  
Pickup Ions ◽  
The Magnetic Field

I address the ion dynamics at the front of magnetosonic shocks moving at different angles θ to the magnetic field vector. I employ a shock discontinuity model in which the ramp potential difference is taken into account. The analysis conditionally separates all the ions incoming to the front of oblique magnetosonic shocks into the following categories: 1) transient, 2) reflected, 3) gyrating in front of the ramp, 4) pickup in the ramp. Both gyrating and pickup ions are shown to be present temporarily at the magnetosonic shock front at any angles θ. In the end, both the former and the latter appear to be transient in a strictly transversal magnetosonic shock; and either transient or reflected, in an oblique magnetosonic shock. I have found the critical angle θ* that separates ions into transient and reflected in an oblique magnetosonic shock. The critical angle θ* depends both on the velocity of the particles, incident on ramp, and on dimensions of the ramp potential difference. The most important results are that I have identified the physical cause of the production of the reflected ions having a significant energy and have revealed the mechanism for their acceleration in the ramp (surfing). In the near-Earth shock ion foreshock, these very ener-getic ions (from tens to hundreds of keV) escaping from the magnetosonic shock front at a small angle to the front plane manifest themselves in observations in the form of so-called field-aligned beams (FABs) and form the ion foreshock boundary.

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