17: Magnetic Dipole Moment
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- Mar 5, 2022
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- A number of different units for expressing magnetic dipole moment (hereafter simply “magnetic moment”) are commonly seen in the literature. It can be almost an impossibility, for example, to write down a list of the magnetic moments of the planets in order of increasing magnetic moment if one refers to the diverse literature in which the moments of each of the nine planets are quoted in different units. This chapter explores some of these aspects of magnetic moment.
- 17.2: The SI Definition of Magnetic Moment
- If a magnet is placed in an external magnetic field B , it will experience a torque. The magnitude of the torque depends on the orientation of the magnet with respect to the magnetic field. There are two oppositely-directed orientations in which the magnet will experience the greatest torque, and the magnitude of the magnetic moment is defined as the maximum torque experienced by the magnet when placed in unit external magnetic field.
- 17.3: The Magnetic Field on the Equator of a Magnet
- The magnetic field at a point at a distance r on the equator of a magnet may be expressed as a series of terms of successively higher powers of 1/r.
Thumbnail: Magnetic fields can be visualized with iron filings, that align along the magnetic field direction. Here the magnetic field of a homogeneously magnetized cylindrical bar magnet was accurately computed, and the field is shown with simulated randomly placed iron filings. The density of filings is also proportional to the field strength. The field is strongest around the magnetic poles. (CC BY-SA 4.0; Geek3 via Wikipedia)
