Plasma particles and families of ionized gases
Ionized gases and plasmas

In what follows, we shall confine ourselves to the case of gaseous plasmas.

The latter are a mixture of electrons, ions and neutral particles. Since electrons have a much lower mass than other particles :m_H/m_e = 1,836

ions and neutrals are called heavy particles.

Because of their low mass, electrons are much faster than heavy particles. Given the high energy of particles in a plasma, heavy particles, or at least some of them, can be in an excited state for times of the order of 10 ^{– 6} to...