rkm wrote:The fact that the vortices are more energetic over water is evidence of electric discharge, as water is a better conductor than land.
Discharge is only half of the story. The other half is just electrostatics. If the air is charged, it will cling to an induced opposite charge in a conductor, such as a body of water. The electric force can then prevent the air from rising as it is heated, thereby building up more thermal potential than would have been possible otherwise. The heat comes from a surface (water or land) that is hotter than the air. So the air is being heated. But to get the concentration of buoyancy in these vortexes, something has to prevent the air from rising as it normally would. This is why fluid dynamic simulators won't reproduce these things -- you can get Rayleigh-Benard cells in a simulator, but you can't get the air to cling to the surface long enough to get heated enough to get dust devils or steam devils, much less tornadoes. This is because the simulators aren't taking the electric force into account. In steam devils, there is also a drift that defies a thermodynamic explanation. If it was just buoyancy, the vortex would just sit right in the middle of the pool of warm air, until it was all gone. But these vortexes consistency slide across the surface, disregarding the ambient wind direction (or absence thereof). Obviously you're not going to get that in a simulator, or in any experimental apparatus. Only if the air is charged will there be a Lorentz force that will cause the vortex to drift. So the energy source is thermal potential, from the surface being warmer than the atmosphere, while the electric force holds the air down until it has enough thermal potential to rise vigorously.