# Encyclopedia Magnetica

Encyclopedia of magnetics and electromagnetics.

magnetic_field

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 magnetic_field [2020/03/18 14:33]Dr Stan Zurek [Difficulty with definition of magnetic field] magnetic_field [2020/03/18 14:35] (current)Dr Stan Zurek [Difficulty with definition of magnetic field] Both sides previous revision Previous revision 2020/03/18 14:35 Dr Stan Zurek [Difficulty with definition of magnetic field] 2020/03/18 14:33 Dr Stan Zurek [Difficulty with definition of magnetic field] 2020/03/07 23:29 Dr Stan Zurek [Magnetic field] 2019/06/03 18:29 external edit2017/01/30 15:06 Dr Stan Zurek -review2016/06/15 15:09 Dr Stan Zurek [Quantities and units] +2016/06/15 15:07 Dr Stan Zurek [Quantities and units] 2016/01/02 22:33 Dr Stan Zurek new math2014/12/03 00:06 Dr Stan Zurek img bkgrnd2014/10/24 20:15 Dr Stan Zurek [Difficulty with definition of magnetic field] 2014/10/23 14:13 Dr Stan Zurek [References] 2014/10/23 14:12 Dr Stan Zurek [Magnetic flux density B] 2014/10/23 14:08 Dr Stan Zurek [Magnetic field strength H] 2014/10/22 14:37 Dr Stan Zurek for review2014/10/21 16:33 Dr Stan Zurek [Difficulty with definition of magnetic field] 2014/10/21 16:30 Dr Stan Zurek [Difficulty with definition of magnetic field] 2014/10/21 15:05 Dr Stan Zurek 2014/10/11 01:18 Dr Stan Zurek +image2014/10/11 00:18 Dr Stan Zurek +refs2014/10/09 23:02 Dr Stan Zurek created 2020/03/18 14:35 Dr Stan Zurek [Difficulty with definition of magnetic field] 2020/03/18 14:33 Dr Stan Zurek [Difficulty with definition of magnetic field] 2020/03/07 23:29 Dr Stan Zurek [Magnetic field] 2019/06/03 18:29 external edit2017/01/30 15:06 Dr Stan Zurek -review2016/06/15 15:09 Dr Stan Zurek [Quantities and units] +2016/06/15 15:07 Dr Stan Zurek [Quantities and units] 2016/01/02 22:33 Dr Stan Zurek new math2014/12/03 00:06 Dr Stan Zurek img bkgrnd2014/10/24 20:15 Dr Stan Zurek [Difficulty with definition of magnetic field] 2014/10/23 14:13 Dr Stan Zurek [References] 2014/10/23 14:12 Dr Stan Zurek [Magnetic flux density B] 2014/10/23 14:08 Dr Stan Zurek [Magnetic field strength H] 2014/10/22 14:37 Dr Stan Zurek for review2014/10/21 16:33 Dr Stan Zurek [Difficulty with definition of magnetic field] 2014/10/21 16:30 Dr Stan Zurek [Difficulty with definition of magnetic field] 2014/10/21 15:05 Dr Stan Zurek 2014/10/11 01:18 Dr Stan Zurek +image2014/10/11 00:18 Dr Stan Zurek +refs2014/10/09 23:02 Dr Stan Zurek created Line 39: Line 39: ​ |< 100% 10% 30% 30% 30%>​| ​ |< 100% 10% 30% 30% 30%>​| ​ - ^ Publication ^ Definition of //​[[magnetic field]]// ^ Definition of //​**[[magnetic field strength]]**//​ $H$ ^ Definition of //​**[[magnetic flux density]]**//​ $B$ ^ + ^ Publication ^ Definition of //**[[magnetic field]]**// ^ Definition of //​**[[magnetic field strength]]**//​ $H$ ^ Definition of //​**[[magnetic flux density]]**//​ $B$ ^ | Richard M. Bozorth \\ **Ferromagnetism**[([[http://​google.com/​books?​isbn=0780310322|Richard M. Bozorth, Ferromagnetism,​ IEEE Press, 2003, ISBN 0780310322, p. 1-3]])] | //A magnet will attract a piece of iron even though the two are not in contact, and this action-at-a-distance is said to be caused by the magnetic field, or field of force.// | //The strength of the field of force, the magnetic field strength, or magnetizing force H, may be defined in terms of magnetic poles: one centimeter from a unit pole the field strength is one oersted.// | //Faraday showed that some of the properties of magnetism may be likened to a flow and conceived endless //lines of induction// that represent the direction and, by their concentration,​ the flow at any point. [...] The total number of lines crossing a given area at right angles is the flux in that area. The flux per unit ara is the flux density, or //magnetic induction//,​ and is represented by the symbol B.// | | Richard M. Bozorth \\ **Ferromagnetism**[([[http://​google.com/​books?​isbn=0780310322|Richard M. Bozorth, Ferromagnetism,​ IEEE Press, 2003, ISBN 0780310322, p. 1-3]])] | //A magnet will attract a piece of iron even though the two are not in contact, and this action-at-a-distance is said to be caused by the magnetic field, or field of force.// | //The strength of the field of force, the magnetic field strength, or magnetizing force H, may be defined in terms of magnetic poles: one centimeter from a unit pole the field strength is one oersted.// | //Faraday showed that some of the properties of magnetism may be likened to a flow and conceived endless //lines of induction// that represent the direction and, by their concentration,​ the flow at any point. [...] The total number of lines crossing a given area at right angles is the flux in that area. The flux per unit ara is the flux density, or //magnetic induction//,​ and is represented by the symbol B.// | | David C. Jiles \\ **Introduction to Magnetism and Magnetic Materials**[(Jiles)] | //One of the most fundamental ideas in magnetism is the concept of the magnetic field. When a field is generated in a volume of space it means that there is a change of energy of that volume, and furthermore that there is an energy gradient so that a force is produced which can be detected by the acceleration of an electric charge moving in the field, by the force on a current-carrying conductor, by the torque on a magnetic dipole such as a bar magnet or even by a reorientation of spins of electrons within certain types of atoms.// | //There are a number of ways in which the magnetic field strength H can be defined. In accordance with the ideas developed here we wish to emphasize the connection between the magnetic field H and the generating electric current. We shall therefore define the unit of magnetic field strength, the ampere per meter, in terms of the generating current. The simplest definition is as follows. The ampere per meter is the field strength produced by an infinitely long solenoid containing //n// turns per metre of coil and carrying a current of 1///n// amperes.// | //When a magnetic field H has been generated in a medium by a current, in accordance with Ampere'​s law, the response of the medium is its magnetic induction B, also sometimes called the flux density.// | | David C. Jiles \\ **Introduction to Magnetism and Magnetic Materials**[(Jiles)] | //One of the most fundamental ideas in magnetism is the concept of the magnetic field. When a field is generated in a volume of space it means that there is a change of energy of that volume, and furthermore that there is an energy gradient so that a force is produced which can be detected by the acceleration of an electric charge moving in the field, by the force on a current-carrying conductor, by the torque on a magnetic dipole such as a bar magnet or even by a reorientation of spins of electrons within certain types of atoms.// | //There are a number of ways in which the magnetic field strength H can be defined. In accordance with the ideas developed here we wish to emphasize the connection between the magnetic field H and the generating electric current. We shall therefore define the unit of magnetic field strength, the ampere per meter, in terms of the generating current. The simplest definition is as follows. The ampere per meter is the field strength produced by an infinitely long solenoid containing //n// turns per metre of coil and carrying a current of 1///n// amperes.// | //When a magnetic field H has been generated in a medium by a current, in accordance with Ampere'​s law, the response of the medium is its magnetic induction B, also sometimes called the flux density.// |