Extension of a Bohm model for L-mode electron heat transport to ion heat transport and to the ohmic regime

The results of simulations of several JET L-mode and ohmic discharges performed with a Bohm-like expression for both ion and electron thermal diffusivities are presented. Comparisons with experimental ion and electron temperature profiles of auxiliary heated discharges show that chi(i) has to be at least twice larger than chi(e) to simulate the L-mode regime even for shots with dominant electron heating. Simulations of ohmic discharges with currents ranging from 1 to 7 MA show that the Bohm-like model for the L-mode is preferable to a neoalcator-like expression of the electron thermal diffusivities.