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Investigating Terrestrial Gamma Flash Production from Energetic Particle Acceleration in Lightning using TETRA-II

LA

Louisiana State University/Southern University/Xavier University of Louisiana/NASA Glenn Research Center, Science Mission Directorate, International Space Station

The goal of this EPSCoR-funded project is to better understand a component of lightning-producing storms called terrestrial gamma flashes, or TGFs. The project also will build research infrastructure at three minority institutions in two EPSCoR jurisdictions and train underserved minority students. TGFs are a significant but not yet completely understood component of the electric structure of thunderstorms. They’re intense, millisecond-scale fluxes of gamma rays associated with terrestrial lightning that were discovered by NASA’s Compton Gamma Ray Observatory and have been observed, as well, by detectors on the AGILE and Fermi spacecraft. These observations indicate that electrons are accelerated to very high energies by the electric fields in lightning, producing showers that radiate high fluxes of x-rays and gamma rays. The TGF and Energetic Thunderstorm Rooftop Array II, or TETRA-ll, will collect important data complementary to Fermi’s observations of the currents associated with these electromagnetic showers. In collaboration with the University of Puerto Rico “Bayamón” using seed support from the Louisiana Board of Regents and Louisiana Space Grant Consortium, TETRA-ll’s expanded, higher resolution, detector arrays will be deployed in Puerto Rico and Jamaica where lightning activity is extremely high and where the prime orbiting TGF detector (the Gamma ray Burst Monitor on NASA’s Fermi mission ““ GBM) indicates that the rate of TGFs is also high. Two HBCUs, Southern University and Xavier University, will commission/operate the new arrays as well as analyze data for climate models and weather-predictive systems. Lightning is a major concern for NASA due to potential damage from strikes to space vehicles at launch and launch and assembly infrastructure. Lightning is also the focus of NASA’s space-based Lightning Imaging Sensor (LIS) aboard the EOS TRMM satellite and an LIS instrument scheduled for launch to the International Space Station in 2016. TETRA detector unit: 19 cm x 19 cm x 0.56 cm NaI (Tl) scintillator viewed by Lucite light pipe and 12.7 cm diameter photomultiplier tube. The TETRA-I array of gamma ray detectors have operated in Baton Rouge, Louisiana since July 2010. TETRA-I consists of an array of twelve 19 cm x 19 cm x 5 mm NaI (Tl) scintillators in four separate detector boxes deployed on rooftops on the LSU campus. TETRA-I has observed thirty-six TGF-like events, mainly during spring and summer thunderstorms, in which 50 keV – 2 MeV gamma rays are observed at ground level in shorter than 5 msec bursts associated with nearby (< 5 km) negative polarity lightning.

www.nasa.gov/epscor/stimuli

Dr. Michael L. Cherry, Science PI, Professor, Louisiana State University

Nasser Barghouty, NASA Technical Monitor, Manager, Astrophysics Office at NASA-Marshall Space Flight Center

NASA EPSCoR Stimuli 2014-15

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EPSCoR Stimuli 2014-15  

NASA Office of Education’s Aerospace Research & Career Development (ARCD) is pleased to release NASA EPSCoR Stimuli, a collection of univers...

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