This is not a scientific explanation – I’m just playing around with a crazy thought experiment. I have absolutely nothing to back this up with.
However – I wonder if it would be possible to create an evaporating spherical capacitor similar to the imaginary hail capacitor described below?
Hails are large, layered ice particles, often spherical in shape, which are produced by thunderstorms having strong, tilted updrafts. The hail get a new shells on it´s journey up and down in the cloud – as described in the picture below.
The shells within a hail can be seen if you cut a hail in half. Here’s a beautiful picture of a half of a hail.
Let´s say that the different shells within the hail have different conducting properties. Lets assume that the shell formed at higher altitudes will be have less conductivity then the shells formed at lower altitudes. The different shells would then have different abilities to accumulate electrons. The hail would form a layered spherical conductor “floating” up and down in the cloud accumulate more and more electrons in the shells with high conductivity while the less conductive shells would insulate prior shells. Hers a small animation showing the process:
As more and more shells are added the inner shells will get compressed and cracks in the insulating cells will appeared making it possible for electrons to “escape” to another shell. I try to illustrate this below:
The hail will “leak” electrons to the lower part of the cloud giving it a negative charge as shown below.
Eventually the potential difference between a hail (or a local part of the cloud) and the ground will be lead to a discharge. Nearby hails will then also discharge in a cluster effect as creating a thunderbolt.
Lets say that a large charged hail drops down to the ground. Lets say the surface of the hail consist of a shell with low conductivity. The conductivity would get higher as the hail melts and electrons would be able to “leak” out. The hail would evaporate and simultaneously discharge seen as a ball lightning as shown in the animation below.
Note again that this is a truly pseudo-scientific explanation! It´s merely one of the crazy thought experiments I use to play around with 🙂