K. Omidvar et Wd. Pesnell, HIGH-SPEED CORRECTION FACTOR TO THE O-O RESONANCE CHARGE-EXCHANGE COLLISION FREQUENCY(), Annales geophysicae, 13(3), 1995, pp. 253-255
The high-speed correction factor to the O+-O collision frequency, resu
lting from drift velocities between ions and neutrals, is calculated b
y solving the integral expression in this factor both numerically and
analytically. Although the analytic solution is valid for either small
or large drift velocities between ions and neutrals, for temperatures
of interest and allo drift velocities considered, agreement is found
between analytic and detailed numerical integration results within les
s than 1% error. Let T-r designate the average of the ion and neutral
temperatures in K, and u = upsilon(d)/alpha, where upsilon(d), is the
relative drift velocity in cm s(-1), and alpha = 4.56 x 10(3) root T-r
cm s(-1) is the thermal velocity of the O+-O system. Then, as u range
s from 0 to 2, the correction factor multiplying the collision frequen
cy increases monotonically from 1 to about 1.5. An interesting result
emerging from this calculation is that the correction factor for tempe
ratures of aeronomical interest is to a good approximation independent
of the temperature, depending only on the scaled velocity u.