  We study ionization and transport processes in partially ionized
multicomponent plasmas. The plasma composition is calculated via a system of
coupled mass action laws. The electronic transport properties are determined by
the electron-ion and electron-neutral transport cross sections. The influence
of electron-electron scattering is considered via a correction factor to the
electron-ion contribution. Based on this data, the electrical and thermal
conductivity as well as the Lorenz number are calculated. For the thermal
conductivity, we consider also the contributions of the translational motion of
neutral particles and of the dissociation, ionization, and recombination
reactions. We apply our approach to a partially ionized plasma composed of
hydrogen, helium, and a small fraction of metals (Li, Na, Ca, Fe, K, Rb, Cs) as
typical for hot Jupiter atmospheres. We present results for the plasma
composition and the transport properties as function of density and temperature
and then along typical P-T profiles for the outer part of the hot Jupiter HD
209458b. The electrical conductivity profile allows revising the Ohmic heating
power related to the fierce winds in the planet's atmosphere. We show that the
higher temperatures suggested by recent interior models could boost the
conductivity and thus the Ohmic heating power to values large enough to explain
the observed inflation of HD 209458b.
