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What is a Tesla?

Michael Anissimov
Michael Anissimov
Michael Anissimov
Michael Anissimov

The tesla is an SI unit for measuring the strength of a magnetic field. Its symbol is T. The unit is named after the famous inventor Nikola Tesla, who discovered the alternating current, among hundreds of other phenomena. A magnetic field of one tesla is about 30,000 times as powerful as the Earth's magnetic field. However, because the quantity of teslas is computed by dividing the total magnetic flux (power) by area, magnetic fields of high tesla can be achieved by concentrating them in a small space.

For a magnetic flux density to equal 1 tesla, a force of 1 newton must act on a wire of length 1 meter carrying 1 ampere of current. A newton -- the force required to accelerate a 1 kg weight at one meter per second squared -- is a lot of force for a magnetic field to exert, and is not easily achieved. The most powerful superconducting electromagnets only produce magnetic fields of around 20T.

An electromagnet. Magnetic field strength is measured in teslas.
An electromagnet. Magnetic field strength is measured in teslas.

The most powerful continuous magnetic field yet generated measures 45T, and the strongest destructive pulse magnet about 850T. A gauss, another unit for measuring magnetism, is 1/10,000th of a tesla. The gamma, still another unit used in geophyics to measure magnetic fields, is one billionth of a tesla.

A weber, another SI unit, is used to measure magnetic flux, whereas the tesla is used to measure magnetic flux density, commonly understood as a magnetic field. It is possible for a given material to become entirely saturated with magnetic flux. For example, 10 teslas is considered to be the upper limit of niobium-titanium accelerator magnets.

The Earth's magnetic field is equivalent to 1/30,000th of a tesla.
The Earth's magnetic field is equivalent to 1/30,000th of a tesla.

Medical magnetic resonance imaging typically sustains a field strength of 2T. A large loudspeaker magnet generates 1T. Exotic cosmic objects such as the magnetar, a neutron star with a massive magnetic field, produce between 0.1 and 100 gigateslas. This is enough to wipe a credit card at a distance equivalent to the gap between the Earth and the Sun.

Michael Anissimov
Michael Anissimov

Michael is a longtime AllTheScience contributor who specializes in topics relating to paleontology, physics, biology, astronomy, chemistry, and futurism. In addition to being an avid blogger, Michael is particularly passionate about stem cell research, regenerative medicine, and life extension therapies. He has also worked for the Methuselah Foundation, the Singularity Institute for Artificial Intelligence, and the Lifeboat Foundation.

Michael Anissimov
Michael Anissimov

Michael is a longtime AllTheScience contributor who specializes in topics relating to paleontology, physics, biology, astronomy, chemistry, and futurism. In addition to being an avid blogger, Michael is particularly passionate about stem cell research, regenerative medicine, and life extension therapies. He has also worked for the Methuselah Foundation, the Singularity Institute for Artificial Intelligence, and the Lifeboat Foundation.

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Discussion Comments

anon346840

It is obvious that the magnetic field force is a relatively weak field force. It is surprising but a no-brainer that smaller surfaces same ampere must have a stronger tesla as a result. Really interesting.

How many teslas do I need to push a 4 Mega Newton. When using more coils, this can be achieved. Twelve coils can reach that goal easier than six coils. right?

Multiplying 4MN / 12 coils makes .7 or .8MN per coil. And you have a perfect wormdrive. --Christian K.

Diablosniper

So measuring lets say a 'rare earth magnet' is going to be measured in Gauss and not Tesla, correct?

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    • An electromagnet. Magnetic field strength is measured in teslas.
      By: zigzagmtart
      An electromagnet. Magnetic field strength is measured in teslas.
    • The Earth's magnetic field is equivalent to 1/30,000th of a tesla.
      By: Mopic
      The Earth's magnetic field is equivalent to 1/30,000th of a tesla.
    • Magnetic resonance imaging in the medical field typically sustains a field strength of 2T.
      By: jovannig
      Magnetic resonance imaging in the medical field typically sustains a field strength of 2T.