Accession Number : ADA316472

Title :   Step Potential Modification by the Lightning Electromagnetic Environment.

Descriptive Note : Technical rept.,

Corporate Author : ARMY COMMUNICATIONS-ELECTRONICS COMMAND FORT MONMOUTH NJ

Personal Author(s) : Tobias, John M.

PDF Url : ADA316472

Report Date : SEP 1996

Pagination or Media Count : 13

Abstract : The purpose of this report is to introduce a modified theory of propagation for lightning currents in earth. Recent experimental evidence has pointed to modified current flow distributions near earth grounding systems subjected to natural electric fields in excess of the fine weather electric field. Current distributions in earth due to lightning discharges are of interest to safety professionals due to the development of the step potential. This step potential examination considers the space charge region developed in the earth as a consequence of the charge present in a thunderstorm cloud. It is theorized that, under certain conditions, the step potential may be significantly higher than previous theoretical estimates, or empirical results obtained under fine weather electric field conditions. The objective of this report is to present the theory of the influence of the cloud charge on current distribution and, hence, step potential by citing recent qualitative observations of rocket-triggered lightning studies. Behavioral description of the step potential will be developed from electromagnetic theory. Impact of the modified step potential on personnel electrical hazards will be discussed. The presentation concludes with suggestions for further research in this area.

Descriptors :   *LIGHTNING, *ELECTRICAL GROUNDING, ELECTROMAGNETIC FIELDS, HAZARDS, VOLTAGE, CURRENT DENSITY, ELECTRIC FIELDS, ELECTRICAL CONDUCTIVITY, CHARGE DENSITY, EARTH SURFACE, ELECTRIC CURRENT, CLOUD PHYSICS, SPACE CHARGE, THUNDERSTORMS, ELECTROMAGNETIC ENVIRONMENTS, CUMULONIMBUS CLOUDS.

Subject Categories : Meteorology
      Electricity and Magnetism

Distribution Statement : APPROVED FOR PUBLIC RELEASE