There have been so many cases of numerical modelling of the equatorial electrojet (EEJ) that only the following selection is cited here: Sugiura and Cain (1966), Untiedt (1967), Sugiura and Poros (1969), Krylov et al. (1973), Richmond (1973a,b), Fambitakoye et al. (1976), Richmond (1979), Marriot et al. (1979), Forbes (1981), Hanuise et al. (1983), Anandarao and Raghavarao (1979, 1987), Raghavarao and Anandarao (1980, 1987), Gagnepain et al. (1976), Forbes and Lindzen (1976b), Takeda and Maeda (1980, 1981), Singh and Cole (1987a,b,c, 1988). Sugiura and Cain (1966) is probably the first truly numerical model of EEJ. It assumes complete inhibition of vertical current and its main feature is the conductivity σyy for eastward current. For that, it acquired the name of σyy model.