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In interpreting the results of active space experiments with charged particles injected in the near Earth space it is important to determine the change of potential of the injecting spacecraft and the disturbed plasma characteristics in its vicinity. The structure of the plasma-beam system in the vicinity of a beam-injecting spacecraft is rather intricate. APEX was a diversified project with an emphasis on the neutralization problem and the dynamics of the spatial charge zone of spacecraft. Since the injection heights range was from 400 to 3,500 km where additional neutralization mechanisms do not work there was a possibility to study the total scope of the above mention problems. It is shown that by changing the injection current in accordance with a certain law we can obtain a medium with the required properties in the spacecraft environment. A comprehensive analysis will allow an appropriate injection regime to be selected. The time and space variations of electron density in space charge zone of spacecraft are determined by the magnitude and the sign of injected current variations as well as by the experimental parameters., JAXA Special Publication, 宇宙航空研究開発機構特別資料

The classical estimations give the maximum potential of spherical satellite (spacecraft) during the electron beam injection in the ionosphere that much exceed the value obtained in real rocket experiments even those conducted at night and without artificial neutralization. The possibilities of compensation are considered on the basis of theoretical models taking into account the collective beam-plasma interactions. The examples of numerical modeling of the charge-discharge dynamics are provided for the APEX spacecraft conditions. It is shown that changing the pulse form and rise rate (dI/dt) can change the structure of space charge zone i.e. try to create the strong disturbance or resonance conditions in the time interval of (pi/omega(sub p)) less than or equal to t less than or equal to t(sub ion). From these positions we consider the APEX facilities used to control the inflow current, the spectrum of energetic particles, the high-frequency oscillations and the spatial distribution of optical emissions in the injector vicinity with high time resolution., JAXA Special Publication, 宇宙航空研究開発機構特別資料