Re: Is it possible to transfer power through Electrostatic conduction ?

Hi Sharon,

Nikola Tesla was a brilliant inventor and engineer, and he made significant contributions in the field of electricity and magnetism (among other things). His patent on wireless energy transmission is a fascinating piece of work, and it even works to some degree.

Keep in mind though, that Tesla's patent was filed in 1900. This was, for example, only three years after Thomson's discovery of the electron, and it was more than a decade later that the modern concept of the atom emerged. So while Tesla based his patent on a large body of experimental evidence, his understanding of the evidence was based on dated scientific theory. As scientists in the 21st century, our understanding of Tesla's transmission is going to be different from the way Tesla understood it, because we've learned a bit in the last 110 years.

With that out of the way, let's look at your questions:

"Can we assume the ground as a kind of “cold plasma” which contains ions? Can the ground be assumed as a “charge pool” ? Why ? Of course, the same principle should be also valid for the cold ionosphere plasma."

Sort of. The Earth's surface does have a measurable negative charge that is replenished continuously by lightning strikes that carry large numbers of electrons from the troposphere down to the ground. The ionosphere's conductivity comes mainly from solar ionization, but it is enhanced somewhat by positive charges from the troposphere left behind by the lightning.

That having been said, these net positive and negative charges are not so important for Tesla's invention to work. If they were, then you could think of the ionosphere and ground as two conductors, and transmit direct current (DC) between two towers. But Tesla's power transmission only works with alternating current, and transmits power through the (insulating) lower atmosphere, rather than the (conducting) ionosphere which starts at an altitude of about 80 km.

I found a nice, not-too-technical explanation of Tesla's wireless transmission by William Beaty on his website. I like it because it presents Tesla's design in the framework of modern science, showing how it "really" works (and not just how Tesla thought it did). This brings us to your second set of questions, which I believe basically boil down to whether Tesla used electrostatic induction for his design to work. The answer to this is "no".

Electrostatic induction is, by definition, "static", which means the charge is not changing with time. But as I said before (and as you will see in Beaty's analysis), Tesla's design only works with alternating current, and is carried by electromagnetic (EM) waves between the transmitter and receiver. The difference between this and a regular radio antenna is the separation of the electric and magnetic components of the waves.

Basically, Tesla used an oscillating voltage in the transmitter to induce voltage oscillations in the receiver. This is the E (electric) part of the EM wave. This only works through an insulating medium like the lower atmosphere (in other words, the air acts as a dielectric).

Oscillating currents in a conductor produce oscillating magnetic fields, and the M (magnetic) part of the EM wave is carried in the ground, which is important not as a "charge pool" but as a conductor. The ground carries electric current through the water table, whose conductivity comes from impurity concentrations in the water.

As Beaty shows, Tesla's patent basically works using the same principles as a coaxial cable, with the ground acting as the inside wire and the atmosphere as the insulator outside that. To work well, coaxial cables also need an external conducting shield to confine the electric waves inside the dielectric. And this is where the ionosphere comes in. By reflecting electromagnetic waves back down to earth, the ionosphere helps keep more of the energy down near the ground where it is useful. So in the end the ionosphere is an important part of Tesla's design, if not exactly how he thought it was.

I hope this was useful to you, and I recommend taking a look at some of the links at the bottom of Beaty's page for further discussion. Thanks for an interesting question!