Just a note regarding Tesla coils...
To clarify, the electrical lightning discharges they produce are not fake, thought they are used in shows etc. I can assure you that they are quite real high voltage lightning, just not as high voltage as the weather produces.
If I had a pacemaker that were affected by fluctuations in nearby electro-magnetic fields, I would not get anywhere near a tesla coil, plasma sculpture or anything of the like unless shielded entirely by a faraday cage.
Here is a little experiment you can do to show how tesla coils are REAL lighting. But I warn you do not let children do this, in fact don't do it yourself, just take it as a fact that the effect I describe is true. Definitly do not perform any action listed below or experiment with electricity unless you are knowledgable in high voltage experiments. Now with that said here is how you can see the electric discharge from even a very small tesla coil is real and can be dangerous:
Most of us are familiar with "plasma sculptures" if you aren't let me describe them. Plasma sculptures are gas filled glass globes with a miniature tesla coil inside that produces colored filaments of light which radiate from the end of the "coil" to the inside of the glass globe. The effects range from the look of lightning to just "weird" electrical discharges. Usually these sculptures, sold at wal-mart, target, and other stores, are touted as being "interactive" because of you place your hand on them, or even get close enough to them the patterns of electrical activity within them change and tend to follow where you touch. Normally, this is perfectly safe. BUT you can easily make the high voltage escape from the globe by placing a highly conductive material in intimate contact with the OUTSIDE surface of the glass -- say, a coin like a quarter, or even better, a gold wedding band. When this happens the conductive object becomes highly charged and a "bolt" of electricity will fly to the closest grounded or neutral object its new high voltage state will allow. Depending upon the voltage of the tesla coil inside the spark or bolt may be large or small -- generally, with plasma sculptures, the bolt is only at the most 3 milimeters in length, but that 3 mm is enough to burn a hole in flesh or even start a fire under proper conditions. To show this you can place a coin on a plasma sculpture then place your finger a couple of milimeters above the coin. This will cause a spark of electricy to jump from the coin to your finger, where it will proceed to burn tiny holes in your skin. You will not feel a shock because of the high frequency of the discharges but you will burn from the heat of the spark, and nearby radios can and will be affected adversly by the disruption caused by the radio frequency of the discharges, just like when lightning strikes -- only to a lesser degree and smaller range.
Lightning from an unshielded telsa coil is much like the sparks from the coin-- only bigger. It generally doesn't cause "shocking" because of its frequency, but the bolts are still hot, still ionize the surrounding air and when big enough produce thunder. To a limited extent, tesla coils and other high voltage devices that produce lightning can also produce x-rays.
Also, you will notice that digital watches will freak out when very close to a tesla coil, jacobs ladder or other high voltage source... I wouldn't want to risk anything that could be harmed by the low level output of a cellular phone by placing it near a high level output of a tesla coil.
--Lovecraft, mad scientist