In the afterglow of a plasma, also known as remote plasma, the external electromagnetic fields that sustained the plasma glow are absent or insufficient to maintain the discharge. A plasma afterglow
can either be a temporal, due to an interruped (pulsed) plasma source, or a spatial one, due to a distant plasma source. In the afterglow, plasma-generated
species de-excite and participate in secondary chemical reactions that tend to
form stable species. Depending on the gas composition, superelastic collisions may continue to sustain the plasma in the afterglow for a while by
releasing the energy stored in rovibronic degrees of freedom of the atoms and molecules of the plasma.
Especially in molecular gases, the plasma chemistry in
the afterglow is significantly different from the plasma glow.