magnetic_energy_density

plasmapy.formulary.misc.magnetic_energy_density(B: Quantity) → Quantity

Calculate the magnetic energy density.

Aliases: ub_

Parameters:

B (Quantity) – The magnetic field in units convertible to tesla.

Returns:

E_B – The magnetic energy density in units of joules per cubic meter.

Return type:

Quantity

Raises:

• TypeError – If the input is not a Quantity.

• UnitConversionError – If the input is not in units convertible to tesla.

• ValueError – If the magnetic field strength does not have an appropriate value.

Warns:

UnitsWarning – If units are not provided, SI units are assumed

Notes

The magnetic energy density is given by:

\[E_B = \frac{B^2}{2 μ_0}\]

The motivation behind having two separate functions for magnetic pressure and magnetic energy density is that it allows greater insight into the physics that are being considered by the user and thus more readable code.

See also

magnetic_pressure

Returns an equivalent Quantity, except in units of pascals.

Examples

>>> import astropy.units as u
>>> magnetic_energy_density(0.1 * u.T)
<Quantity 3978.87... J / m3>