MOTION OF GASEOUS IONS IN STRONG ELECTRIC FIELDS 



215 



and normalized to 1 we get a distribution in the Wz — w^ half plane which 

 is shown in Fig. 12. Division by 2TrWz will transform it into a conventional 

 distribution function in velocity space; a plot of this function is shown 

 in Fig. 13. What distinguishes this distribution function from functions 

 previously proposed is the elongated probability contours. This feature 

 is not unexpected in view of the unequal energy partition apparent in 

 the equations (58) and C60). 



The probability contours sho^\Ti in Figs. 12 and 13 give a reliable general 

 picture but we must not expect from them fine detail. Indeed we will 

 now prove that the distribution function is infinite along the entire 

 positive Cz-axis, a feature which is not obvious from inspection of Fig. 13. 



Fig. 12 — Motion of ions through the parent gas in a high field; distribution of 

 velocities in the w, - w^ half plane resulting from the Monte Carlo calculation. 



