Symbols:Greek/Mu/Vacuum Permeability

Vacuum Permeability

$\mu_0$

The vacuum permeability is the physical constant denoted $\mu_0$ defined as:

$\mu_0:= \dfrac {2 \alpha h} {e^2 c}$

where:

$e$ is the elementary charge

$\alpha$ is the fine-structure constant

$h$ is Planck's constant

$c$ is the speed of light defined in $\mathrm m \, \mathrm s^{-1}$

Of the above, only the fine-structure constant $\alpha$ is a measured value; the others are defined.

It can be defined as the capability of a magnetic field to permeate a vacuum.

From Value of Vacuum Permeability, it has the value:

$\mu_0 = 1 \cdotp 25663 \, 70621 \, 2 (19) \times 10^{-6} \, \mathrm H \, \mathrm m^{-1}$ (henries per metre)

The $\LaTeX$ code for \(\mu_0\) is \mu_0 .

Variant

$\Gamma_m$

Vacuum permeability can also be seen denoted as $\Gamma_m$ in some older works.

The $\LaTeX$ code for \(\Gamma_m\) is \Gamma_m .

Sources

• 1969: J.C. Anderson, D.M. Hum, B.G. Neal and J.H. Whitelaw: Data and Formulae for Engineering Students (2nd ed.) ... (previous) ... (next): $3.$ Physical Constants