Radar studies of lightning-induced plasmas with potential applications to radio communications and space surveillance

The problem of radio backscatter from lightning-induced plasmas is briefly reviewed. The predicted wavelength dependence of the backscattered power is compared to observations made with the MIT S band, C band and the Millstone UHF radar. The analysis is extended to a pancakelike plasma created through single radar beam heating of the atmosphere. The artificial plasmas are modeled as perfectly conducting, rough plasma disks, with random surface inhomogeneities described by either a Gaussian or power law type spectrum. Both monostatic and bistatic radar geometries are considered. These may be used in diagnostic and space surveillance/radio communication applications, respectively. The wavelength dependence of the radio reflectivity of a plasma pancake with Gaussian type surface roughness is found to be different from that of a plasma with a power law type surface roughness in the backscatter radar geometry. In the radio communication and space surveillance applications, the radio reflectivity may be independent of the incident wavelength, if the surface density inhomogeneities are characterized by an azimuthally symmetric power law type spectrum. By contrast, a wavelength dependence is expected for the Gaussian type spectrum.