Theoretical Evaluation of Peek´s Law

A theoretical evaluation for Peek´s law which yields the corona onset gradient is made in air for positive wire/cylinder and positive point/plane geometries. The physical and geometrical parameters used in Meek´s criterion take into account the variation of apparent ionization coefficient ¿1 of air with humidity, pressure, and temperature and the curvature radius R of the rod tip (or the wire diameter D). A single analytic integrable expression is introduced for ¿1/P which may be used for any value of the reduced field E/p. The results covering a wide range of parameters 10-7 m < R or D < 107 m (up to a plane/plane geometry) are compared with a variety of experimental results.