ABSTRACT
In this paper, the simultaneous optical and electromagnetic emission as a function of known current have been determined both experimentally and analytically. The experimental measurements were accomplished at the Kiva 1 and 2 facilities atop S. Baldy Peak located in the Magdelena Mountains in central New Mexico. The facility is capable of recording lightning current, electromagnetic fields, and optical emission to at least a 10 ns resolution. The measurements of all variables are time tied to assure comparison of like quantities. Numerical predictions of the optical output for the measured current were made with the magnetohydrodynamic code, CHARTB. The predictions for the electromagnetic fields were made with a simple analytical model. The most important result of this exercise was the determination, through fitting the electromagnetic fields to a particular velocity, that the effective velocity of propagation of the current pulse near the ground was near .9c.
