This project advances understanding of thunderstorm electrification and electrical dynamics by undertaking a detailed analysis of charge motion in a thunderstorm as charge is generated by cloud processes, transported by wind and gravity, discharged by lightning, and conducted in the atmosphere. The research utilizes a proposed network of broad-band electric field sensors deployed in the vicinity of Langmuir Laboratory's radio-frequency Lightning Mapping Array (located in the Magdalena mountains of New Mexico). Data from the two sensor networks along with recently developed mathematical inversion algorithms provide a map of the charge transport in a thunderstorm. Further analysis gives a detailed description of the thunderstorm current generators, the locations in the cloud where positive or negative charge accumulate. The thunderstorm generators are used as input to a mathematical simulation of the thunderstorm in which the electric potential, electric field, and charge density are evaluated everywhere in the modeled domain. The lightning discharge techniques will exploit newly developed mathematical algorithms for computing the change in electric potential due to a lightning discharge. These algorithms express the electric potential change in terms of the graph of the lightning channel. Actual lightning channels, as detected by the Lightning Mapping Array, will be used as input to the lightning discharge algorithm.
The proposed electric field network will specialize in determining charge-flow and current within a thundercloud, important physical quantities that are related to lightning damage to structures, to electrical machines, and to the national electric grid. The lightning discharge routines developed in this proposal could be combined with dynamic cloud models, which describe the wind and moisture associated with a thunderstorm, to obtain a complete description of the microphysics of a thundercloud and the transport and neutralization of charge by lightning. The electric field sensors developed during the proposed research could be operated in conjunction with a radio-frequency Lightning Mapping Array to assess the magnitude of charge clusters in an instrumented region of space. Such instrumentation could, in the future, be deployed near airports and launch facilities to provide air traffic and spacecraft controllers with additional information concerning the likelihood of lightning strikes throughout the instrumented region.
