The magnetospheric barium release experiment of September 21, 1971, was observed by a high-performance image intensifier television camera system from Kitt Peak National Observatory, Tucson, Arizona. The system produced high-resolution video recordings of the dynamic morphology of the barium ion cloud. The system was calibrated for absolute sensitivity, thus enabling the reconstruction of the barium density profiles in the cloud. The ionized plasma expands along the field line with the velocity somewhat greater than the neutral expansion velocity. Perpendicular to the magnetic field line, the expansion of the cloud is limited by the forces exerted by the earth's magnetic field. Thus, the cloud takes up a field-aligned filamentary structure. As early as 30 sec after release, two major filaments could be distinguished. Two minutes after release, the cloud already consisted of at least 8 or 10 filamentary striationlike structures. These are formed in the low-density expanded part of the cloud. These striations and the diffuse parts of the cloud move in a direction perpendicular to the magnetic field with a velocity different from that of the main dense core of the cloud. This differential velocity moves the lower-density parts away from the main core. These lower-density parts appear to be highly structured in the form of fieldaligned striations. During the first 8 min after release, the high-density main core part erodes to a very narrow strip, which is about 12 km wide. This width of the central core is less than the diameter of the gyro-orbit of the initial velocity barium ions in the ambient magnetic field. The rapid fragmentation of the cloud to such narrow forms has interesting implications for the stability of dense magnetospheric plasma clouds.