Parametric Excitation of a Drift Wave and Associated Ion Heating by a Modulated Ion Beam

An ion beam modulated near the lower-hybrid frequency is injected into a low-β plasma immersed in a longitudinal magnetic field. Parametric excitation of a drift wave and a lower-hybrid wave is observed. From the measurement of the threshold electric field, an rf field parallel to the magnetic field is found to play an important role in the excitation of the instability. Substantial increase of the ion and electron temperatures has been observed with the growth of the instability. Such a rapid heating may be principally due to the drift wave instability driven parametrically.