The abundance discrepancy factor and t^2 in nebulae: are non-thermal
  electrons the culprits?
  Photoionization produces supra-thermal electrons, electrons with much more
energy than is found in a thermalized gas at electron temperatures
characteristic of nebulae. The presence of these high energy electrons may
solve the long-standing t^2/ADF puzzle, the observations that abundances
obtained from recombination and collisionally excited lines do not agree, and
that different temperature indicators give different results, if they survive
long enough to affect diagnostic emission lines. The presence of these
non-Maxwellian distribution electrons is usually designated by the term kappa.
Here we use well-established methods to show that the distance over which
heating rates change are much longer than the distance supra thermal electrons
can travel, and that the timescale to thermalize these electrons are much
shorter than the heating or cooling timescales. These estimates establish that
supra thermal electrons will have disappeared into the Maxwellian velocity
distribution long before they affect the collisionally excited forbidden and
recombination lines that are used for deriving abundances relative to hydrogen.
The electron velocity distribution in nebulae should be closely thermal.
