The dataset provides spatiotemporal variation of the electron number density obtained by use of the 23-species RKM in the first seven voltage periods at p = 300 mbar, U_0 = 1.5 kV and f = 24 kHz (T = 41.7 µs). The first column represents the gap distance values in units of meters, while the first row is a time given in units of seconds. Values for electron number density n_e are given as log(n_e [m^-3]).