Kinetic Description of Ponderomotive Effects in a Plasma

The kinetic treatment of the ponderomotive force concept is found from nonresonant quasilinear theory for waves with spatially dependent amplitude. In general, the ponderomotive effect appears as a velocity-space diffusion term, not just as a force. For an unmagnetized plasma, the qualilinear equations are solved directly, and the correct density modification exhibited explicitly. Examples are considered for both a homogeneous and an inhomogeneous magnetic field, and aspects of rf end plugging are discussed.