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Re: TC Characteristics Q's
Hi Jay,
Your unbelief puzzles me, maybe I understand you wrong, but yes it doesn't
really matter what form the top-capacitance is. At some potential there will
be ionization of surrounding air. This occurres mostly on the parts of the
top-cap where the radius is the smallest. That's the reason that it must
have a smooth surface. The reason for this is that sharp points and surfaces
with relatif small radius in general, has concentrated electrical field
lines around them. Therefore the electrical forces are more powerful at said
surfaces and there is a greater change that one or more electrons are
repelled or attracted from or to the top-cap.
The result is that there arise ions (atoms or mulecules with an electrical
charge) in the air.
Those ions can also give away or lone an electron with the help of the
electrical field lines from there neighbors. Eventually there is made an ion
path where the top-cap can discharge through: the arc. And this all has
nothing to do with the scin effect! (BTW: most coilers prefer a toroid, a
sphere is used mostly for electrostatic generators like the 'Van de Graaff'
generator) However a sphere on a TC can have some nice side effects...
Now about your other question: magnetic fields inside the top-cap and the
coils:
1. The more change of current in the less time, the bigger the magnetic
field will be(B=dI/dt).
2. The surface of a sphere is pi*R^2, so the magnetic field will diminish at
least with a power of 2.
3. The more you spare, the bigger your present. ;-)
Conclusions:
With TC work you 'spare' (charge) normally only for 1/2 a 60 or 50 Hz wave,
because it is nice and impressive to have an almost continuous spark. With a
railgun you normally 'spare' longer, so the power supply has an easy job.
Essential is the 'number of Joules' you spared, so high voltage and bigggg
capacitors (E = 1/2C * V^2). So the electromagnetic forces for a railgun are
much bigger than for the average TC. There are reports that you can feel the
magnetic forces in your hand when hold above a small coil when a big cap is
discharging in it, but this seems to be harmless.
The primary coil of the TC is the TC 'driver' and of course this is the
place where the biggest magnetic fields will be. Deminishing with a power of
2, so in the top-cap this field will not be so impressive anymore. That's
the reason that relative long secondary coils aren't more productive then
shorter one's. So, a man in the top-cap of an operating TC? YES! May I, may
I, please?
I hope this all will answer more than it will contribute to the increasing
number of questions you were talking about!
Greetings from lovely and sunny Holland,
Ruud de Graaf