
Figure 8
Freeelectron fraction, p, and (1  p)^{2} as a function of the electric field calculated using equations (14) and (15). The solid and broken lines indicate the results for d = 4.2 and 8.4 mm. The factor of (1  p)^{2} is the ratio of K in equation (6) to that in equation (13), i.e. the rate of change of K. 