Magnetic moment

A vector quantity that measures the strength and orientation of a magnetic dipole. It describes both currents in loops and intrinsic magnetic properties of particles.

Magnetic dipole: A physical system whose magnetic field has a dipole pattern at distances large compared with its size. The moment quantifies the strength and orientation of this field pattern.
Electric current: The rate at which electric charge passes through a surface. A circulating current is the source of the classical loop moment.
Electron magnetic moment: The intrinsic magnetic moment associated with an electron's spin and orbital angular momentum. Its precisely measured value tests quantum electrodynamics.
Electric dipole moment: A vector measuring the separation and orientation of positive and negative electric charge. It is the electric analogue of a magnetic moment, but couples to electric fields.
Torque: A measure of the rotational effect of a force about an axis or point. A magnetic field exerts torque on a dipole moment, tending to align it with the field.
Current loop: A closed conducting path through which electric current flows. Its area and current set the magnitude of its magnetic moment.
Proton magnetic moment: The intrinsic magnetic moment of the proton, arising from its internal quark and gluon dynamics. Its value demonstrates that a proton is not a pointlike Dirac particle.
Magnetic susceptibility: A measure of how strongly a material becomes magnetized in response to an applied magnetic field. Susceptibility describes a material's collective response rather than one dipole's moment.
Potential energy: Energy associated with an object's position or configuration within a conservative interaction. A dipole's energy in a magnetic field depends on the angle between its moment and the field.
Angular momentum: A conserved vector quantity measuring rotational motion. Intrinsic particle moments are linked to spin, while orbital motion also produces magnetic moments.

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