An empirical formula for negative corona discharge current in point-grid electrode geometry

A series of measurements carried out with a point-grid electrode system has clarified that the current-voltage characteristics of the negative corona discharge obey the Townsend relation, further, in which the coefficient is proportional to temperature and the power of the electrode gap independently, and the corona onset voltage is proportional to the product of the reciprocal of temperature and the power of the electrode gap. The empirical formula derived from their relations has estimated negative corona currents with an accuracy of 1μA for a given parameter set, which will allow application to ion generator design.