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.
_________________________________________________________________________________________________
Submitted to: Applied Physics Letter
_________________________________________________________________________________________________
Download PPPL-5209
(pdf 2 MB 13 pp)
_________________________________________________________________________________________________