A Model of Dust Grain Charging: The Influence of the Grain Size
نویسندگان
چکیده
Dust grains — objects of different shapes with a size distribution from micro to nanometers — are generally considered as a part of many space as well as laboratory plasmas. Among various charging processes, electron-induced secondary emission plays an important role wherever plasma contains a noteworthy portion of hot electrons. We have developed a numerical model of charging dust grains due to electron impact that describes all measurable effects rather well. Since we are able to study the charge of a single dust grain irradiated by a monoenergetic electron beam tunable in the energy range from ≈ 100 eV to 10 keV, we can compare the modeled and the measured data. A slight discrepancy between both these profiles for all grain sizes disables direct cross-analysis of profile changes occurring for the smallest grains. In the present work, a series of equilibrium characteristics was measured for ≈ 0.6–3 μm gold grains and an unusual method for matching those provided by the model is shown.
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