☙

tesla

For the meaning of any metric prefix, go here.

The unit of magnetic flux density in SI. Symbol, T. In 1954¹ the International Electrotechnical Commission (IEC) Technical Committee 24 recommended it be added to the Giorgi system, and the 11th CGPM (1960) adopted it as an SI unit.

One tesla is one weber of magnetic flux per square meter of circuit area.

$a fraction, weber over meter squared$

In terms of base units only,

$a fraction, kilogram over seconds squared times amperes$

looking up at the 45-tesla magnet

Courtesy NHMFL, Florida State University

The 45-tesla magnet, seen from below.

One tesla is about the strength of the fields of the largest ordinary electromagnets. Stronger fields can be generated by magnets built with coils made of superconducting conductors. The now-cancelled Superconducting Super Collider was scheduled to have magnets with a 6-tesla field, and the Large Hadron Collider at CERN has 8.4-tesla superconducting magnets. In December 1992, a magnet at the Francis Bitter National Magnet Laboratory at MIT produced a magnetic field of 37.2 teslas, a record. As of 2009, the strongest continuous artificial field was 45 teslas, produced by a hybrid magnet at the National High Magnetic Field Lab.

The Earth's magnetic field, at its surface, is roughly 50 microteslas. The strongest known magnetic fields are those of the type of neutron star called “magnetars,” which are on the order of 10 gigateslas.

portrait of Tesla

The tesla is named for Nikola Tesla (1856–1943), the electrical engineer who, among many other accomplishments, did much to establish alternating current distribution systems.

1. J. J. Smith.
Recommendations of IEC Technical Committee 24: Electric and Magnetic Magnitudes and Units.
Electrical Engineering, volume 74, pages 406–408 (1955).

See page 407.

2. CIPM, 1956, Resolution 3; 11th CGPM, 1960, Resolution 12.

3. B. Kern and C. Martin, Nature, 417, p. 527 (2002).

A. I. Ibrahim, S. Safi-Harb, J.H. Swank, W. Parke, S. Zane and R. Turolla,
Astrophysical Journal Letters, 574, L51 (2002).