Plasma physics formulas (
plasmapy.physics provides theoretical formulas for calculation of
physical quantities helpful for plasma physics. The layout of the
subpackage is still in flux, but for now we have settled on providing a
plasmapy.physics namespace for some of the most common
functions. The actual functions are located in modules, subjectively
grouped by topic, with sub-namespaces for larger sub-packages.
We thus have:
- Plasma parameters (
- Dimensionless parameters (
- Dielectric functions (
- Distribution functions (
- Quantum physics functions (
- Relativistic functions (
- Magnetostatics (
The subpackage makes heavy use of
astropy.units.Quantity for handling
conversions between different unit systems. This is especially important
for electron-volts, commonly used in plasma physics to denote
temperature, although it is technically a unit of energy.
Most functions expect
astropy.units.Quantity as input, however some
will use the
plasmapy.utils.check_quantity decorator to automatically
cast arguments to Quantities. If that happens, you will be notified via
Please note that well maintained physical constant data with units and
uncertainties can be found in
For a general overview of how unit-based input works, take a look at the following example:
Notes for developers¶
Values should be returned as an Astropy Quantity in SI units.
If a quantity has several names, then the function name should be the one that provides the most physical insight into what the quantity represents. For example, ‘gyrofrequency’ indicates gyration, while Larmor frequency indicates that this frequency is somehow related to a human (or perhaps a cat?) named Larmor. Similarly, using omega_ce as a function name for this quantity will make the code less readable to people who are unfamiliar with the notation or use a different symbol.
The docstrings for plasma parameter methods should describe the physics associated with these quantities in ways that are understandable to students who are taking their first course in plasma physics while still being useful to experienced plasma physicists.