Experimental Investigation of Ion Cyclotron Resonance Acceleration in a Nonuniform Magnetic Field

Ion acceleration of a plasma in a nonuniform magnetic field by an rf field is investigated. The ions are accelerated along the axis of the magnetic line due to the µ∇ // B force, where µ is the magnetic moment of an ion of which energy is increased through cyclotron damping of electrostatic ion cyclotron wave and ∇ // B is the magnetic field gradient along the axis. Ions are accelerated to about 200 eV at rf electric field of 60 V/cm. The computed results of the dispersion relation of the wave including cyclotron damping agree well with the experimental ones.