Now showing items 1-7 of 7

    • The angular distribution of energetic electron and X-ray emissions from triggered lightning leaders 

      Schaal, M.M.; Dwyer, Joseph R.; Rassoul, Hamid K.; Hill, Jonathan David; Jordan, Douglas M.; Uman, Martin A. (2013-10-27)
      We investigate individual X-ray bursts from lightning leaders to determine if energetic electrons at the source (and hence X-rays) are emitted isotropically or with some degree of anisotropy. This study was motivated by ...
    • "Chaotic" dart leaders in triggered lightning: Electric fields, X-rays, and source locations 

      Hill, Jonathan D.; Uman, Martin A.; Jordan, Douglas M.; Dwyer, Joseph R.; Rassoul, Hamid K. (2012)
      We present the first published observations of "chaotic" dart leaders in triggered-lightning discharges. We examine four leaders that exhibited "chaotic" electric field derivative (dE/dt) signatures in their final 10 to ...
    • Do cosmic ray air showers initiate lightning?: A statistical analysis of cosmic ray air showers and lightning mapping array data 

      Hare, B. M.; Dwyer, Joseph R.; Winner, Lawrence H.; Uman, Martin A.; Jordan, Douglas M.; Kotovsky, D. A.; Caicedo, J. A.; Wilkes, R. A.; Carvalho, Filipa L.; Rassoul, Hamid K. (2017)
      It has been argued in the technical literature, and widely reported in the popular press, that cosmic ray air showers (CRASs) can initiate lightning via a mechanism known as relativistic runaway electron avalanche (RREA), ...
    • First images of thunder: Acoustic imaging of triggered lightning 

      Lucia, R.; Rassoul, Hamid; Dayeh, M. A.; Evans, N. D.; Fuselier, Stephen Anthony; Trevino, J.; Ramaekers, J.; Dwyer, Joseph R.; Kotovsky, D. A.; Jordan, Douglas M. (2015-07-16)
      An acoustic camera comprising a linear microphone array is used to image the thunder signature of triggered lightning. Measurements were taken at the International Center for Lightning Research and Testing in Camp Blanding, ...
    • High-speed X-ray images of triggered lightning dart leaders 

      Dwyer, Joseph R.; Schaal, M. M.; Rassoul, Hamid K.; Uman, Martin A.; Jordan, Douglas M.; Hill, Dustin (2011-10-26)
      We present the first high-time resolution two-dimensional images of X-ray emissions from lightning. The images were recorded at a rate of 10 million per second using a new pinhole-type camera, located 44 m from rocket-and-wire- ...
    • Observations of stepping mechanisms in a rocket-and-wire triggered lightning flash 

      Biagi, Christopher J.; Uman, Martin A.; Jordan, Douglas M.; Rakov, Vladimir A.; Dwyer, Joseph R.; Hill, Jonathan D. (2010-12-14)
      We present 10 high-speed video images that depict the bottom 150 m of a downward-negative, dart-stepped leader in a rocket-and-wire triggered flash, recorded at 240 kiloframes per second (4.17 μs frame integration time), ...
    • Spatial and energy distributions of X-ray emissions from leaders in natural and rocket triggered lightning 

      Schaal, Meagan M.; Dwyer, Joseph R.; Saleh, Ziad H.; Rassoul, Hamid K.; Hill, Jonathan D.; Jordan, Douglas M.; Uman, Martin A. (2012)
      Energetic radiation is known to be produced by lightning. To investigate these emissions, ground-based observations are being conducted at the International Center for Lightning Research and Testing (ICLRT) at Camp Blanding, ...