AbstractSmall electrostatic fields of values not strong enough to activate electron impact ionization, attachment, and detachment processes can be established in the upper atmosphere by underlying thunderstorms. This paper investigates their effects on the ionospheric densities by using a simplified ion chemistry model. The modeling results indicate that under the steady state condition, the nighttime electron density profile can be reduced by up to ∼40% or enhanced by a factor of up to ∼6 because of the variation of the three‐body electron attachment rate constant with the electric field.