Fast Photometric Imaging Using Orthogonal Linear Arrays

A new optical instrument has been developed that captures 2-D images at high speed and high sensitivity using 1-D photomultiplier tube arrays. The arrays are orthogonally aligned, and using a coaligned video-speed imager, fast images can be reconstructed using matrix inversion techniques. The instrument can be used to make measurements of optical signatures of energetic electron precipitation induced by discrete waves (e.g., lightning discharges and very-low-frequency transmitter pulses), as well as measurements of high-speed high-altitude glow discharges in the upper atmosphere known as sprites, halos, and ELVES. In this paper, we introduce the instrument and present some first results of sprites and ELVES, and we discuss how the instrument can improve upon current observations in other experiments.