Debye-Hückel screening and fluctuations

The Debye-Hückel theory of screened Coulomb potentials, originally born in chemical physics, has long been adopted by the plasma community. Here it has been applied to a system which is close to but not quite at thermal equilibrium. It has been shown how the presence of small local fluctuations leads to a sizeable contribution to line broadening as demonstrated for the Liman-α line of hydrogen. The conditions for this type of broadening effect are sufficiently unspecific that similar effects are likely to be found in a variety of different systems.