Mag_Reynolds¶

plasmapy.formulary.Mag_Reynolds(U: Unit("m / s"), L: Unit("m"), sigma: Unit("S / m")) -> Unit(dimensionless)¶

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

\[Rm = \frac{U L}{\eta}\]

where \(\eta = \frac{1}{\mu_0 \sigma}\) and \(\mu_0\) is the permeability of free space.

Aliases: Rm_

Parameters:	U (`Quantity`) – The velocity scale of the plasma. L (`Quantity`) – The length scale of the plasma. sigma (`Quantity`) – The conductivity of the plasma.
Warns:	~astropy.units.UnitsWarning – If units are not provided, SI units are assumed.
Raises:	`TypeError` – The `U` is not a `Quantity` and cannot be converted into a ~astropy.units.Quantity. `UnitConversionError` – If the `U` is not in appropriate units.

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 – Dimensionless quantity.
Return type:	`Quantity`