BEAM-TYPE INSTABILITIES OF THE SHEATH IN A GRAZING MAGNETIC-FIELD

A plasma sheath in a strongly tilted magnetic held is considered. It i s shown that, if the incoming plasma flux contains two ion populations with clearly distinguishable energies (e.g., an admixture of cold ion s to the main ion distribution), vigorous beam-type instabilities may be excited in the sheath. One should emphasize that these instabilitie s may be present even if the ion distribution function in the bulk of the plasma does not have beam structure. (C) 1997 American Institute o f Physics.