File constants.hxx# Variables constexpr BoutReal PI = 3.141592653589793# Mathematical constant pi. constexpr BoutReal TWOPI = 2 * PI# Mathematical constant 2 * pi. namespace SI# Variables constexpr BoutReal c = 299792458# Speed of light in vacuum. constexpr BoutReal mu0 = 4.e-7 * PI# Permeability of free space. constexpr BoutReal e0 = 1 / (c * c * mu0)# Permittivity of free space. constexpr BoutReal qe = 1.602176634e-19# Electron charge. constexpr BoutReal Me = 9.10938356e-31# Electron mass. constexpr BoutReal Mp = 1.672621898e-27# Proton mass. constexpr BoutReal kb = 1.38064852e-23# Boltzmanns constant. constexpr BoutReal amu = 1.660539040e-27# Unified atomic mass unit. constexpr BoutReal M_Hydrogen = 1.008 * amu# Mass of a Hydrogen atom. constexpr BoutReal M_Deuterium = 2.01410178 * amu# Mass of a Deuterium atom. constexpr BoutReal M_Tritium = 3.0160492 * amu# Mass of a Tritium atom.