HIGH-SPEED CORRECTION FACTOR TO THE O-O RESONANCE CHARGE-EXCHANGE COLLISION FREQUENCY()

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.