NOAO/KPNO--NSO,

DEPARTMENT OF ASTRONOMY

AND STEWARD OBSERVATORY

AND NRAO

The University of Arizona

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JOINT COLLOQUIUM

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presents

Professor E. Philip Krider

of

The University of Arizona, Department of Atmospheric Sciences, Institute of Atmospheric Physics

who will present a talk entitled

"Current Topics in Lightning Research"

Astract: Lightning is a significant weather hazard and a threat to ground-based observing systems. In this talk, we will review the physical processes that occur during a typical cloud-to-ground flash, and then we will describe some results of our research at The University of Arizona. The topics to be covered include the luminous development of a cloud-to-ground flash, the sub-microsecond structure of lightning radiation fields, the production of X-rays by rocket-triggered discharges, and the basic elements of lightning protection.

on Thursday, October 16, 2003

at 4:00 p.m.

in Steward Observatory Lecture Hall-Room N210

**Refreshments at 3:30 p.m. in the Lobby**