plasmapy.formulary.gyroradius(B: Unit("T"), particle='e-', *, Vperp: Unit("m / s") = <Quantity nan m / s>, T_i: Unit("K") = <Quantity nan K>) -> Unit("m")

Aliases: rc_, rhoc_

Parameters: B (Quantity) – The magnetic field magnitude in units convertible to tesla. particle (str, optional) – Representation of the particle species (e.g., 'p' for protons, 'D+' for deuterium, or 'He-4 +1' for singly ionized helium-4), which defaults to electrons. If no charge state information is provided, then the particles are assumed to be singly charged. Vperp (Quantity, optional) – The component of particle velocity that is perpendicular to the magnetic field in units convertible to meters per second. Must be input as a keyword argument. T_i (Quantity, optional) – The particle temperature in units convertible to kelvin. Must be input as a keyword argument. r_Li – The particle gyroradius in units of meters. This ~astropy.units.Quantity will be based on either the perpendicular component of particle velocity as inputted, or the most probable speed for an particle within a Maxwellian distribution for the particle temperature. Quantity TypeError – The arguments are of an incorrect type UnitConversionError – The arguments do not have appropriate units ValueError – If any argument contains invalid values ~astropy.units.UnitsWarning – If units are not provided, SI units are assumed

Notes

One but not both of Vperp and T_i must be inputted.

If any of B, Vperp, or T_i is a number rather than a Quantity, then SI units will be assumed and a warning will be raised.

The particle gyroradius is also known as the particle Larmor radius and is given by

$r_{Li} = \frac{V_{\perp}}{omega_{ci}}$

where $$V_{\perp}$$ is the component of particle velocity that is perpendicular to the magnetic field and $$\omega_{ci}$$ is the particle gyrofrequency. If a temperature is provided, then $$V_\perp$$ will be the most probable thermal velocity of an particle at that temperature.

Examples

>>> from astropy import units as u
<Quantity 0.002120... m>
<Quantity 0.002120... m>
<Quantity 288002.38... m>