Lightning and Sprite Imager (LSI) Onboard JEM-GLIMS

Abstract

Lightning and Sprite Imager (LSI) is a science instrument of JEM-GLIMS to capture images of lightning discharges and upper atmospheric transient luminous events (TLEs), such as sprites, elves and blue jets. LSI consists of two CMOS cameras; one is a wide-band camera named LSI-1 that is equipped with an optical filter whose pass-band ranges from 765nm to 830nm, the other is a narrow-band camera named LSI-2 that is equipped with an optical filter whose transmittance centers at the wavelength of 762nm and has band width of 14nm. From the comparison of LSI-1 images with LSI-2 images the time evolution and spatial distribution of lightning discharges and TLEs can be identified. Since the telemetry speed provided for JEM-GLIMS is limited, LSI images will be acquired not continuously but intermittently according to the onboard event trigger logic. This trigger logic selects only the transient optical flashes caused by lightning discharges or TLEs effectively.