Electrical self-polarization in intracloud lightning flashes

Abstract

We present a theoretical microphysical model of thundercloud electrification that incorporates the influence of an aerosol with electrical self-polarization (pyroelectric) like methane. We estimate the water and methane dipole contribution to the internal electric field of a cloudy cell. Using a cloudy cell like a cube of 3.6 Km side, we obtain that the water contribution to the internal electric field, due to the electrical displacement vector generated by the atmospheric electric field of the Earth, is not enough to produce a typical discharge; the methane increases the electric field inside the thunderclouds and facilitates the electrical charge generation and separation process. We calculate the associated capacitance for the cloudy cell and the internal electric field. The results obtained for the charge of a cloudy cell due to a methane concentration (using a concentration lower than the air composition) and water, seem to agree with recent observations in lightning