Stanford University Sprites 1998 Campaign

Two unique optical instruments are deployed for targeted measurements of features of sprites and elves that are deemed most important in terms of physical understanding of the underlying mechanisms of these phenomena, as well as their effects on the mesosphere and the lower ionosphere overlying active thunderstorms. In addition, very low frequency strip holographic imaging of associated ionospheric disturbances are being conducted using the Holographic Array for Ionospheric Lightning (HAIL), involving a north-south array of ten stations deployed between Cheyenne, Wyoming and Las Vegas, New Mexico.

The two optical instruments currently deployed at Langmuir Labs are:

• Dobsonian Sprite Experiment (DSE) is a 16-inch wide, 6-ft tall telescope with a field-of-view of 0.7 degrees, which is boresighted with a wide field-of-view video camera. The DSE provides a resolution of about 10 meters at a range of 500-km, and is targeted at measurement of streamer structure predicted to exist in sprites. The telescopic imaging conducted with the DSE represents the highest spatial resolution measurement to date of sprites, elves and related atmospheric phenomena, and complements other ground- and aircraft-based measurements being carried out durign Summer 1998.
• The Fly's Eye is an array of photomultipier tubes designed to time-resolve the horizontal development of intense sub-millisecond ionospheric optical flashes that have come to be known as "elves". The Fly's Eye was designed and built at Stanford University and deployed during the 1996 and 1997 Sprites Campaigns. For this year, a new trigger mechanism has been designed to specifically capture elves produced by negative cloud-to-ground and intracloud discharges, as well as conduct simultaneous measurements of the same points in the sky with blue and red filters. In addition, the Fly's Eye photometer constellation will be used in conjunction with the Dobsonian Sprite Experiment, to resolve temporal features of streamers and other sprite features observed in telescopic field-of-view.