Optical emission and peak electromagnetic power radiated by return strokes in rocket-triggered lightning

In the mid-1980's, Guo and Krider [1982, 1983] made calibrated measurements of the optical signatures produced by negative cloud-to-ground (CG) lightning in the visible and near-infrared (VNIR) spectral region. These measurements were correlated with electric field waveforms to determine the type of lightning process that produced the optical radiation. More recently, Quick and Krider [2013] made similar measurements on natural lightning in correlation with video data and reports from the U.S. National Lightning Detection Network (NLDN) that provided estimates of the peak stroke currents. Here, we will describe optical measurements of rocket-triggered lightning (RTL) strokes in the VNIR spectral band that were obtained using calibrated sensors and were then correlated with currents measured directly at the channel base. The results show that the total optical output (in the VNIR band) at the time of the peak current is only about 5% of the total electromagnetic (or Poynting) power radiated at that time. Our methods and assumptions are similar to those of Guo and Krider [1982, 1983] and Quick and Krider [2013].