force_drift

plasmapy.formulary.drifts.force_drift( F: Quantity, B: Quantity, q: Quantity, ) → Quantity[source]

Calculate the general force drift for a particle in a magnetic field.

Aliases: vfd_

Parameters:

F (Quantity) – Force acting on particle
B (Quantity) – Magnetic field
q (Quantity) – Particle charge

Returns:

v – Drift velocity, in m/s

Return type:

Quantity

Notes

The particle drift in a magnetic field and with a general force (e.g. gravity) applied to it is given by

\[\vec{v} = \frac{\vec{F} × \vec{B}}{q |B|^2}\]

Note the charge dependency.

Examples

>>> import astropy.units as u
>>> from astropy.constants.si import g0, e, m_e
>>> ex = np.array([1, 0, 0])
>>> ez = np.array([0, 0, 1])
>>> force_drift(-ez * g0 * m_e, ex * 0.01 * u.T, e)
<Quantity [ 0.0000000e+00, -5.5756984e-09,  0.0000000e+00] m / s>
>>> force_drift(-ez * g0 * m_e, ez * 0.01 * u.T, e)
<Quantity [ 0., -0.,  0.] m / s>
>>> force_drift(-ez * g0 * m_e, ex * u.T, e)
<Quantity [ 0.0000000e+00, -5.5756984e-11,  0.0000000e+00] m / s>