In order to characterize transient chargingphenomena of a spacecraft with artificial ion beamemission, charging of an electrically floated bodywith a small ion source was experimentally studiedin a vacuum chamber. Charging rate of the beamemitting electrically floated body (dVbody/dt) wascontrolled by a parameter, Ib/C, where Ibcorresponds to the ion beam current, and C is thecapacitance of the floated body. For a wide rangeof Ib/C parameter, it was found that dVbody/dt=Ib/C atthe beginning of the charging. Then the chargingslows down because the current emitted from thebody drastically decreased as a result of a spacecharge limited ion flow developed in front of the ionsource. This space charge limited flow showsoscillatory behaviors of ions at frequencies around10 Hz, 1 kHz , and 300 kHz, corresponding to ionmovement in the space charge limited region.
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