PPPL-5209

Modeling thermionic emission from laser-heated nanoparticles

Authors:  J.M. Mitrani, M.N. Shneider, B.C Stratton, and Y. Raitses
 
Abstract:  An adjusted form of thermionic emission is applied to calculate emitted current from laser-heated nanoparticles, and to interpret time-resolved laser-induced incandescence (TR-LII) signals. This adjusted form of thermionic emission predicts significantly lower values of emitted current compared to the commonly-used Richardson-Dushman equation, since the buildup of positive charge in a laser-heated nanoparticle increases the energy barrier for further emission of electrons. Thermionic emission inlfuences the particle's energy balance equation, which can aff ect TR-LII signals.  Additionally, reports suggest that thermionic emission can induce disintegration of soot aggregates when the electrostatic Coulomb repulsion energy between two positively charged primary particles is greater than the van der Waals bond energy. Since the presence of aggregates strongly influences the particle's energy balance equation, using an appropriate form of thermionic emission to calculate emitted current is essential for interpreting TR-LII signals.
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Submitted to: Applied Physics Letter
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Download PPPL-5209 (pdf 2 MB 13 pp)
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