ABSTRACT
In recent investigations of wave interaction with intense plasmas sustained in magnetic multicusps (MCs) [1-4], it was observed that electromagnetic standing waves (SW) are realized along the axis of the minimally magnetized (|Bo| < 1 gauss) plasma column [2]. The origin of the SW was attributed to the penetration and inadequate screening of the wave fields reflected from the conducting radial boundary [3,4] and from the axial plasma-vacuum interface at the ends [2,3]. During the investigation of the SW phenomenon, measurement of the axial plasma floating potential was performed [2], which indicated that the variation of the potential closely follows the SW pattern, leading to the possibility of localization of plasma electrons in the SW intensity minima (troughs) [2]. However, detailed experimental confirmation of the localization, including investigation of the origin and nature of the interaction leading to axial localization of the electrons in the presence of a predominantly transversely polarized (TE11) [3,4] wave fields, has not been carried out earlier. Such a study is useful not only from the basic physics point of view but also from the viewpoint of emerging applications like wave plasma-based focused ion beams [5,6], plasma thrusters for space propulsion [7,8], and so on, many of which employ compact MC [9-11] for generation, sustenance, and confinement of wave-induced plasmas.
