Top: dependence of the relaxation time τ_d for charge deviations on the grain’s radius a. The results presented for NaCl grains immersed in typical plasma conditions expected at r ~ 5.7R_J distance in the Jupiter system (see text). The result (i) is obtained for the generalized J_s model (7) and compared to results (ii) obtained using the Sternglass approximation for SEE. Bottom: dependence of the charge number |⟨N⟩| on grain’s radius a with the same parameters and notation as for Fig. 5 (top).