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Re: Superconducting magnifier
From: Ted[SMTP:tedric-at-generation-dot-net]
Sent: Sunday, November 09, 1997 4:20 PM
To: Tesla List
Subject: Re: Superconducting magnifier
>
>From: Steve Rodway[SMTP:Legion-at-bigfoot-dot-com]
>Sent: Sunday, November 09, 1997 1:26 PM
>To: Tesla List
>Subject: Re: Superconducting magnifier
>
>Tesla List wrote:
>>
>> From: Ted[SMTP:tedric-at-generation-dot-net]
>> Sent: Sunday, November 09, 1997 2:28 AM
>> To: Tesla List
>> Subject: Re: Superconducting magnifier
>>
>> >From: Steve Rodway[SMTP:Legion-at-bigfoot-dot-com]
>> >Sent: Thursday, November 06, 1997 7:51 AM
>> >To: Tesla List
>> >Subject: Re: Superconducting magnifier
>> >
>> >Tesla List wrote:
>> >>
>> >> From: Jim Lux[SMTP:jimlux-at-earthlink-dot-net]
>> >> Sent: Tuesday, November 04, 1997 10:13 AM
>> >> To: Tesla List
>> >> Subject: Re: Superconducting magnifier
>> >>
>> >> > As I understand it the superconducting effect is destroyed by intense
>> >> > magnetic fields because they destroy the electron coupling. Since
>> >> > powerfull feilds are the aim in Tesla coils, I don't think that any sort
>> >> > of superconducting system could work, sorry to dash your hopes, but
>> >> > that's physics for you.
>> >>
>> >> I don't think the magnetic field in a tesla coil would be high enough to
>> >> quench the superconductor.
>> >
>> >Are you sure about that? The fields as the spark gap fires should be
>> >very intense around the primary
>>
>> Steve,
>>
>> First of all, thanks for the physics. But haven't I already mentioned
>> critical magnetic field in my post? I guess you were just trying to
remind me.
>>
>> Although I am no expert in this field, I believe you are not too, since you
>> used the qualitative term "intense". May I ask you how much is intense, half
>> a Tesla? a Tesla or 10 Tesla? You are simply not talking science.
>>
> OK, the field strenght produced in a coil is given by h=NI/l, given a
>typical primary might have 15 turns, be 20cm high, and have a peak
>current of 1000A, this gives a peak value for the field strength to be
>75,000A/m. Looking a several reference texts in library, I find a
>typical value for the critical field to be around 5,000A/m, so the
>critical field is easily exceeded.
Steve,
Knowing little is dangerous, even more than knowing nothing. There is an
article called "Building World-Record Magnets" in Scientific American, June
1995. I only see the term gauss through out the entire article, what is the
conversion between A/M and gauss? In page 63, it is written that
"superconducting magnets have so far been limited to about 200,000 gauss."
In case you don't know, 1 gauss = 10^-4 tesla, we are talking about 20 T, do
you realize how much that is? Also, which type of superconductors are you
referring to: I or II. Which type? What is the name of the superconductor?
Also, according to the same article, a conventional resistive electromagnet
can attained an even higher magnetic field-maximum at 30T, but with an
"impresive plumbing circulates deionized, highly pressurized WATER throught
the magnets, to keep them cool." Is that a better idea that a
SUPERCONDUCTING coil that requires only liquid nitrogen. Also, all this
magnets mentioned have a (not air) core. Does tesla coil have one?
Let me tell you a secret: "Proving something is impossible is just a waste
of time, with the pace of today's technological innovation, today's dream is
tommorrow's reality." A scientist can show you all kind of calculation why a
humble(?) bee can't fly, but is that true? I believe that when someone
overemphasizes "science", he/ she will eventually come to a point where he/
she will stop accepting new ideas. After all, our science is just a bunch of
proved hypothesis, when the hypothesis cannot describe the fact, all we need
is a new hypothesis. How do you know the electrons come in pair? Because a
Noble Prize winner said that then you have to believe it? It is the only or
the best theory for explaining superconductivity? Does it apply to ceramic
superconductors (think twice on this)? Do you know what is espistemology?
Have you tried the experiment? So how come you still don't get my point.
Once again, there is not enough magnetic flux that cuts the superconductors
to renders it useless. As written in page 708 of College Physics, 7th
ediion, by Sears/ Zemansky/ Young:"If the lenght L of the solenoid is large
in comparison with its cross-sectional radius R, the B field INSIDE the
solenoid near its CENTER is very nearly uniform and PARALLEL TO THE AXIS,
and the field OUTSIDE, adjacent to the center, is VERY SMALL." If it is
written in a book and you can't understand it, I have nothing to say. If you
can't visualize the magnetic field around the coil, get a software that
shows magnetic field distribution. Do you actually think that with a
distance of an inch (between primary and secondary), the magnetic field can
increase from practically none to 75,000A/M? Don't forget we are talking
about an air core solenoid here that has a diameter of at least a foot.
To prove that who is wrong, get a device known as the four points probes,
you can purchase it from Colorado Superconductor Inc. I have an old
catalogue, but new price can be found in their site. Do the suggested
experiment by replacing nails with superconductor. Don't forget to tell me
the result. I guess you will only accept what I said by doing the experiment
yourself.
Ted