Tesla – The unit of magnetic field strength

The unit Tesla (T) is one of the most important physical units in magnetism. It is used to measure the magnetic flux density and thus indirectly the magnetic field strength. The unit was named after the well-known engineer and inventor Nikola Tesla and is used in the International System of Units (SI). The Tesla unit plays a crucial role in electrical engineering, physics and medical technology in particular.

The Tesla Unit in Magnetism

The unit of magnetic field strength Tesla (T) is defined as follows:

1 Tesla corresponds to the magnetic flux density that exerts a force of 1 Newton (N) on a conductor 1 meter long through which 1 ampere (A) of current flows.

Expressed mathematically:

This means that the stronger the interaction between a magnetic field and a current-carrying line, the greater the magnetic flux density.

Difference between magnetic field strength and magnetic flux density

The terms magnetic field strength and magnetic flux density are often used synonymously, although they are physically different:

• The magnetic flux density (B) is given in Tesla (T) and describes how strong a magnetic field is in a certain medium and indicates the strength of the remanence.
• The unit magnetic field strength (H) indicates how strong a magnetic field is, regardless of the surrounding material.

The relationship between both quantities is described by the permeability (μ) of the material.

Here, μ is made up of the magnetic field constant (μ0) and the relative permeability (μr) of the medium. This physical relationship shows that the magnetic field strength is not measured directly in Tesla but has its own unit.

Gauss and Tesla are units for magnetic flux density. In the SI system, the magnetic field strength is given in the unit Oersted or Ampere per meter:

Tesla and other magnetic units of measurement

In other unit systems, the magnetic flux density is measured in Gauss (G). The conversion between Tesla and Gauss is:

This means that 1 Gauss is equal to 0.0001 Tesla. In addition to Tesla, there is also the smaller unit millitesla (mT):

1 T = 1.000 mT

Application of the unit Tesla

The magnetic field strength unit Tesla is used in many areas of technology and science. It is particularly important in the following applications:

• Electromagnetism: Measurement of magnetic fields in transformers, electric motors and generators
• Medicine: Magnetic field strength in magnetic resonance imaging (MRI) is given in Tesla (e.g. 1.5 T or 3 T scanners)
• Research: Investigation of superconducting magnets and plasma experiments
• Geophysics: Research into the Earth's magnetic field, which is measured in nanotesla (nT)

Tesla and its relevance

The Tesla unit is the most important unit for measuring magnetic flux density and plays a crucial role in modern science and technology. Although it is often confused with magnetic field strength, both terms are different. Due to the increasing use of magnetic fields in medical technology, electrical engineering and research, the Tesla unit remains highly relevant.