Spherically Symmetric Model of the Photoelectron Sheath For Moderately Large Plasma Debye Lengths
The potential distribution is investigated in the neighbourhood of a conducting, electron emitting sphere surrounded by a collisionless plasma. The energy dependence of the emitted electrons is adopted in accordance with data on photoemission, but their spatial distribution is treated spherically symmetric. A Maxwellian velocity distribution with zero average velocity is assumed for the undisturbed plasma electrons. The ions are taken as uniform background. A self consistent solution of the collisionless Boltzmann equation for the electrons and Poisson’s equation has been obtained by an iterative scheme. Results are presented for plasma parameters corresponding to solar wind conditions at 1 AU. The role of the plasma- and photoelectron Debye lengths is discussed.
KeywordsSurface Potential Potential Minimum Collisionless Plasma Solar Wind Condition Maxwellian Velocity Distribution
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