by CharlesChandler » Fri Feb 05, 2010 6:05 pm
There is, no doubt, an electric current inside the tornado. This has been confirmed by a variety of methods, and has been estimated at 100~250 amps. That doesn't seem like a lot, but when motivated by tens of millions of volts over a distance of several kilometers, that works out to hundreds of millions of watts. And that's enough power to make the current a reentrant thermodynamic factor as well. In other words, the low pressure inside the updraft reduces the resistance of the air, which opens up a conduit for the flow of electricity. The electric current heats the air, which reinforces the updraft. Hence the updraft and the current inside it are mutually-enhancing, and this results in a self-stabilizing concentration of forces.
But such thinking drives us head-long toward a brick wall. Instinctively we would frame the concept of an "electric tornado" as a discharge between the cloud and the ground. Yet if that was the case, tornadoes would display an unmistakable preference for differences in conductivity in the ground. For example, they would latch onto things like railroad tracks and rivers, and refuse to break away until the storm had moved closer to some other high-conductivity feature on the ground. Yet this is definitely not the case. Thousands of tornado tracks have been analyzed, and the cases where the tornadoes appeared to follow geographic features were simple coincidences, well within statistical predictions. This left the researchers scratching their heads, wondering how there could be that much current, and no distinct preference for conductivity in the ground.
Yet if we look at an even broader set of observations, it all makes sense. The air flowing into the tornado has developed an electric charge. This, also, has been confirmed by a variety of methods. The sign of the charge is positive, and the strength of the charge induces an opposite charge in the surface of the Earth, resulting in an electrostatic attraction that makes the air hug the ground as it approaches the tornado. The charge inside the cloud is negative. So while the inflowing air is attracted to the Earth, the negative charges inside the cloud are attracted to the positively-charged air flowing into the vortex. The low pressure inside the vortex enables the flow of current. But it's not from the cloud down to the ground, but rather, from the cloud down into the air flowing into the tornado. Where positive and negative charges meet inside the tornado, the positive charge that was binding the air to the surface is neutralized. So the air is now free to ascend in response to the low pressure aloft. It is also heated by the current, which makes it rise faster, and which makes it an even better conductor.
At first blush, this appears to be a strange concoction of extraneous facts, that magically develop these extreme properties. But these are well-known facts, and the mutually-enhancing nature of these forces could only result in an extreme concentration of the effect. And this is precisely the nature of tornadoes. And while there are many theories concerning the nature of tornadoes, there is only one way to work all of the way through it, with no spare parts left on the table when we're done. Tornadoes are the result of the interactions among several different types of factors. They are fundamentally a fluid dynamic phenomenon, and fluid dynamics can account for 99% of the overall amount of energy getting expended. But fluid dynamics can only account for about 15% of the energy getting expended directly at the surface of the Earth. So we can get a vortex with the fluid dynamic factors present, but not one as robust as a tornado, and not one that is so well-defined at the surface. The EM factors, by themselves, can account for some of the phenomena, but fall well short of a complete description. But when we put it all together, we find that tornadoes do not pick up a little bit of force from fluid dynamics, and a little bit more from EM, and such adds up to 100%. Rather fluid dynamics has 15%, EM has 15%, and the combinatorial effects add up to 100%.
Within this framework, the complete range of distinctive properties of tornadoes can be explained.
Give a man a fish and you feed him for a day. Teach a man to fish and he'll spend the rest of the day sitting in a small boat, drinking beer and telling dirty jokes.
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