Probing electric fields near sprites and jets using multiparameter radar and chaff

The discovery of electric discharges above thunderstorms has generated intense scientific interest. Studies of these 'sprites' and 'jets' have focused on their characterization by optical and radio techniques, with radar measurements of the causative storms providing insight into related weather. The authors describe a method for investigating the electric field structure above thunderstorms using ground-based radar to observe chaff dispersed by rockets. Slender conducting or dielectric chaff will generally align itself with the ambient electric field. This alignment is readily detected by appropriate configurations of polarimetric radar(s) such as are now used in meteorology to observe the nature and motion of hydrometeors. This is especially convenient as it permits the thunderstorms associated with sprites and jets to be characterized with the same experimental facility. This paper renders a preliminary examination of factors such experiments would entail and features that a multiparameter radar might utilize to probe chaff dispersed by small rockets. Monostatic and bistatic radar measurements of scatter from chaff provide a powerful tool to study electric fields associated with sprites and jets as well as other atmospheric electric fields.