beta

plasmapy.formulary.dimensionless.beta(T: Quantity, n: Quantity, B: Quantity) → Quantity[source]

Compute the ratio of thermal pressure to magnetic pressure.

The beta (\(β\)) of a plasma is defined by

\[β = \frac{p_{th}}{p_{mag}}\]

where \(p_{th}\) is the thermal pressure of the plasma and \(p_{mag}\) is the magnetic pressure of the plasma.

Parameters:

T (Quantity) – The temperature of the plasma.
n (Quantity) – The particle density of the plasma.
B (Quantity) – The magnetic field in the plasma.

Examples

>>> import astropy.units as u
>>> beta(1 * u.eV, 1e20 * u.m**-3, 1 * u.T)
<Quantity 4.0267...e-05>
>>> beta(8.8e3 * u.eV, 1e20 * u.m**-3, 5.3 * u.T)
<Quantity 0.01261...>

Returns:: beta – Dimensionless quantity.
Return type:: Quantity