A·m²
ampere square meter
Magnetic momentexact by definition
The ampere square metre is the SI unit of magnetic dipole moment written in its current-loop form, exactly equal to the joule per tesla. A single turn of wire enclosing one square metre and carrying one ampere has a moment of one A·m². A small neodymium magnet is a few tenths of one, and the Earth's dipole moment is about 7.7e22. The equality is exact, the two forms being the same coherent SI unit.
| 1 A·m² | 1 J/T |