nT
nanotesla
Magnetic flux densityexact by definition
The nanotesla is one billionth of a tesla, and it is the unit of the whole geomagnetic field science. The Earth's field of about 50 microteslas is 50000 nT; a magnetic storm moves it by a few hundred; an archaeological feature or a buried steel drum shows up in a survey as a few nT against that background. The factor of 1e-9 is exact, being an SI prefix.
| 1 nT | 1.0000000e-09 T |
Where the unit came from
Geophysics called this unit the gamma, exactly 1 nT, from the 1890s until the SI name displaced it. Older survey maps and geomagnetic indices are contoured in gammas, and the numbers transfer with no conversion at all. The gamma's own glyph is not carried on this site because it has no font metrics in the renderer.
Solvers that use magnetic flux density