Laboratory Observations of Ion-Cyclotron Waves Associated with a Double Layer in an Inhomogeneous Magnetic Field.
IOWA UNIV IOWA CITY DEPT OF PHYSICS AND ASTRONOMY
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Observations of coherent electrostatic ion-cyclotron EIC waves associated with a strong, magnetized double layer are presented. The double layers are produced by applying a positive potential to an electrode located in a diverging, solenoidal magnetic field region of a weakly ionized argon plasma. Ionization within the electrode sheath is essential to the formation of these double layers. The resulting V-shaped potential structures have extended parallel, oblique and perpendicular electric field components. The frequency of the ion-cyclotron instability is dependent upon the position of the magnetic field-aligned potential structure. The propagation properties of the EIC waves are presented, and a discussion is given of the possible excitation mechanisms.
- Plasma Physics and Magnetohydrodynamics