Constants
=========

For convenience, the PICMI interface defines the following constants,
which can be used directly inside any PICMI script. The values are in SI units.

- ``picmi.constants.c``: The speed of light in vacuum.
- ``picmi.constants.ep0``: The vacuum permittivity :math:`\epsilon_0`
- ``picmi.constants.mu0``: The vacuum permeability :math:`\mu_0`
- ``picmi.constants.q_e``: The elementary charge (absolute value of the charge of an electron).
- ``picmi.constants.m_e``: The electron mass
- ``picmi.constants.m_p``: The proton mass