sentences:  Magnetospheric double layers typically have a strength formula_1 (where the electron temperature is assumed to lie in the range formula_2) and are therefore weak.A series of such double layers would tend to merge, much like a string of bar magnets, and dissipate, even within a rarefied plasma.It has yet to be explained how any overall localised charge distribution in the form of double layers might provide a source of energy for auroral electrons precipitated into the atmosphere.