Observation of double layers in a convergent magnetic field

An experimental investigation is presented in which an unusually stable space charge double layer is created in a low-pressure argon discharge in a convergent magnetic field. On the high potential side of the double layer unstable high-frequency oscillations are observed. First experimental results seem to indicate that the high-frequency oscillations exert an observable influence on the plasma density by leading to a flattening of the radial/axial density profile on the high potential side of the double layer