Fermi Gamma-ray Space Telescope

Sprite observations by GRT-WF: - Correlative study of Sprites and TGFs -

Takanori Sakamoto
K. Watanabe, J. Hegley, E. Vydra, A Luke, J. Schiltz (FGCU), T. Okajima, N. Geherls (GSFC)

Abstract:

The physical connection between thundercloud associated optical phenomena known as sprites and terrestrial gamma-ray flashes (TGFs) are still not clear. Correlative study between sprites and TGFs is in great interest to understand the acceleration process of electrons inside the thundercloud. Based on the scientific motivation, we construced the wide field optical camera system (GRT-WF) using the off-the-shelf hardware. One of the unit of GRT-WF is composed of Watec 902H2 Ultimate camera and Fujinon YV2.7x2.9LR4D-SA2 lens (F=0.95). The field of view of the camera is ~60 x ~60 deg. Seven cameras point along azimuth directions and one camera points at zenith direction to cover entire visible sky. GRT-WF is located at Florida Gulf Coast University (FGCU), Fort Myers, Florida where has a high thunderstorm activity during summer. UFOCaptureV2 software (SonotaCo.com) is used to capture the events. The scientific observation of GRT-WF has started since June 2011. We have detected more than hundreds of sprites. We show a temporal and a positional correlation between the Fermi/GBM detected TGFs and our sprite events.