The ALOFT mission: a flight campaign for TGF and gamma-ray glow observations over Central America and the Caribbean in July 2023

Abstract

The Airborne Lighting Observatory for FEGS and TGFs (ALOFT)  is a field campaign focused on observing Terrestrial Gamma-ray Flashes (TGFs) and gamma-ray glows from thunderclouds. ALOFT will be flown on a NASA ER-2 research aircraft, flying at 20 km altitude, and the payload  includes:1) Fly’s Eye GLM Simulator (FEGS), an array of imaging photometers as well as different wavelengths, and electric field change meters.2) Lightning Instrument Package (LIP), giving three component electric field measurements.3) Several gamma-ray detectors covering four orders of magnitude dynamic range in flux as well as the full energy range for TGF/gamma-ray glow detection.ALOFT is scheduled for July 2023, with 50 flight hours based out of Florida.  Flying over thunderstorms in Central America and Caribbean, one of the most active TGF regions on the planet during the most optimal season, the ALOFT campaign will help us to answer the questions:1) How and under what conditions are TGFs produced?2) How extended in space and time are the gamma-ray glows?To answer question 1), the ALOFT campaign will be supported by ground based radio measurements from different locations in Central America and Caribbean.To answer question 2), with realtime downlink of data we will know when the ER-2 encounters gamma-ray glowing thunderclouds, and we will instruct the pilot to have the aircraft perform have repeated overflights over this cloud as long as the glow exists, to answer question 2).  This will also help us understand whether gamma-ray glows and TGFs are interrelated.The full set of observational goals of ALOFT are:1. Observe TGFs in one of the most TGF-intense regions on the planet.2. Observe gamma-ray glows in thunderstorms and their relation to TGFs.3. Perform International Space Station Lightning Imaging Sensor (ISS LIS) and Global Lightning Monitor (GLM) validation using improved suborbital instrumentation (including upgraded FEGS).4. Evaluate new design concepts for next-generation spaceborne lightning mappers.5. If relevant instrumentation is available, make measurements useful to advance convection science from a suborbital platform.In this presentation we will give the status and plans for the ALOFT mission.