The International Space Station and Denmark, Part 3: ASIM the lightning hunter

Abstract

The ASIM experiment on the ISS is the crowning achievement of a decades long Danish tradition of research into atmospheric electricity in the upper atmosphere. Carol Anne Oxborrow takes us behind the scenes of this DTU-led space mission where new x-ray and gamma-ray detectors are used to observe 'giant lightning' (also known as Transient Luminous Events, TLEs, in English).  These events include red sprites, blue jets and the highly energetic Terrestrial Gamma Flashes (TGFs). The article explains in an engaging manner how ASIM's data has uncovered the complex coupling between ordinary lightning and electromagnetic phenomena in the upper atmosphere and how gamma-rays from magentars far out in the galaxy can incidentally be measured with the experiment's high-energy detectors.  We get a fascinating look into space research's  technical and scientific challenges - from optical photometers with 10 μs time resolution to likelihood images of x-ray photon detections. ASIM shows how this dedicated lightning mission with extremely high time resolution can expose the mysteries of ultra-short but high-energy phenomena in Earth's atmosphere and beyond.