Formation of Potential Double Layers in Plasmas

Large localized potential double layers, $e\ensuremath{\phi}>>k{T}_{e}$, are observed to develop from a solitary $E$-field structure in a plasma traversed by electron drifts, ${v}_{d}\ensuremath{\simeq}{v}_{e}$. Strong electron and ion accelerations occur across the layers. At large electron drift velocities (${v}_{d}>3{v}_{e}$), layers are unstable to large ion fluctuations with $\frac{\ensuremath{\delta}n}{n}$ approaching unity.