reduced_mass

plasmapy.atomic.reduced_mass(test_particle, target_particle) → astropy.units.quantity.Quantity

Find the reduced mass between two particles.

Parameters:

• target_particle (test_particle,) –
• or Constant (Quantity,) – The test particle as represented by a string, an integer representing atomic number, a Particle object, or a Quantity or Constant with units of mass.

Returns:

reduced_mass – The reduced mass between the test particle and target particle.

Return type:

Quantity

Raises:

• InvalidParticleError – If either particle is invalid.
• UnitConversionError – If an argument is a Quantity or Constant but does not have units of mass.
• MissingAtomicDataError – If the mass of either particle is not known.
• TypeError – If either argument is not a str, int, Particle, Quantity, or Constant.

Example

>>> from astropy import units as u
>>> reduced_mass('p+', 'e-')
<Quantity 9.10442514e-31 kg>
>>> reduced_mass(5.4e-27 * u.kg, 8.6e-27 * u.kg)
<Quantity 3.31714286e-27 kg>