# Mag_Reynolds¶

plasmapy.formulary.dimensionless.Mag_Reynolds(U: Unit(‘m / s’), L: Unit(‘m’), sigma: Unit(‘S / m’))

Compute the magnetic Reynolds number

The magnetic Reynolds number is a dimensionless quantity that estimates the relative contributions of advection and induction to magnetic diffusion in a conducting medium.

$Rm = \frac{U L}{η}$

where $$η = \frac{1}{μ_0 σ}$$ and $$μ_0$$ is the permeability of free space.

Aliases: Rm_

Parameters
Warns

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

Raises

Examples

>>> import astropy.units as u
>>> sigma = 5.96e7 * u.S / u.m
>>> U = 10 * u.m / u.s
>>> L = 1 * u.cm
>>> Mag_Reynolds(U, L, sigma)
<Quantity 7.48955689>
>>> rho = 1e-8 * u.S / u.m
>>> U = 0.1 * u.m / u.s
>>> L = 0.05 * u.m
>>> Mag_Reynolds(U, L, sigma)
<Quantity 0.37447784>

Returns

Rm – The magnetic Reynolds number.

Return type

Quantity