Effect of the humidity in the ionic mobility in reduced air-density

It is analyzed the effect of the humidity on the mean ionic mobility in reduced air-density (/spl delta/=0.77). The analysis is supported in corona current-voltage curves using rod-plane DC gaps. The mean ionic mobility in positive polarity it is reduced 1.4% per g/m/sup 3/ while at sea level is reduced 1% per g/m/sup 3/ only; this shows that for positive polarity a reduction of 23% in the relative-air density increases the effect of humidity in approximately 40%. For negative polarity the mean ionic mobility is decreased 1.1% per g/m/sup 3/. Up to now there is still the discussion above the appropriate value of the exponent a in the equation of the steady component of corona current that takes into account the gap distance d:Ic=C/d/sup a/ V(V-Vo). In according to our experimental data a=1.1.