Simulations and experiments of the generation apparatus of the DC electric field with the space charge

To make accurate measurements,field mills must be calibrated in a known DC electric field space charge in which the quantities can be control1ed.A simulation model of the generation apparatus of the electric field with a space charge has been built.Based on the combination of the electric field and the transfer of a dilute substances model,the in-fluence of openings in the metal screen was calculated.Simulation results showed that the opening size of the high‐voltage electrode has a great influence on the distribution of the electric field and ion density at the calibration zone.Next,a generation apparatus was designed and developed and ion mobility was researched.The experimental results showed that ion mobility decreased with an increase in electric field strength.However,ion mobility tends to be saturated when the electric field reaches a certain critical value.Two fitting formulas of ion mobility of positive and negative charge are proposed that can be used to predicate ion mobility in a high electric field.