pulsed fusor theory #2

[guest]

Humm..... Mr Meagley has brought out a good point about amateur capacitor science. I read all his n2 laser posts... cool. I really like his nanos for nickels approach. So in keeping with this update I now have a top end for pulsed fusors. Fingering my Marti Martian mouse pad , I think a really high power setup should be considered.... a Billion amps makes 10^36 neutrons under fourth power scaling! The Harry Diamond Labs showed that fourth power scaling occurs at 4 MAs. I propose that Fifth power scaling kicks in at 1 BA, so the yield could be 10^45 neutrons.
I know of few things that kick out 10^36 or a massive 10^45 neutrons. So is it possible to generate or control such a thing? I took the advice I give to all my begining physics students ... do it in single units to see
if it is possible or if units don't match up then screwup.

First thing the Billion amperes.

Given:***
watts=volts x amps
watt= 1joule/second

1 joule / 1 nanosecond = 1 billion watts

so far ok.

1 billion watts / 1 volt = (you got it ) 1 billion amperes

cool it works.
But you say what is the point?

Now we take what we know works and apply it to a real situation.

Mr Megley's work tends to indicate 4 nanoseconds as
pretty workable.

1 volt is pretty useless in fusor work... but if we put in 34 kev which is only 14 kev above what has been done in n2 lasers.

We then work the formula we just worked in reverse order to see how many joules are needed.

Let's adjust the last equation for the new values.

kev = 1000 volts ***

x watts /34 kev = 1 billion amps.

Let's get out the calculator ( I' m a teacher so bite me.)

x watts turns out to be 3.4 trillion watts

or 3,400,000,000,000 Watts

pretty big huh? (sticks and stones may break your bones but numbers will never hurt me...GWB on the economy)

To find the joules then:

a nanosecond is 1 x 10^-9 Second***

x joules/ 4 nanoseconds = 3.4 trillion watts

x joules = (4 x 10^-9 seconds)(3.4 x 10^12 Watts) = 13.6 x 10^3 joules

To see if this is a practical thing plug it in and see if you like it ....plug and chug... if the cap covers Montana forget it!

joules = 1/2( cap size) ( volts)^2 ***

1.36 x 10^ 4 joules= .5(x cap size )(3.4 x10^4 volts)^2

cap size = 2x1.36 x 10^4 joules /1.156 x 10^9 volts^2 = 2.35 x 10-5 Farads or 23.5 microfarads

it would easily fit in a room!
It would be tubby but doable.

*** For lurkers who wonder how we get this stuff anyway.

Larry Leins
Physics Teacher

[guest]

"The Harry Diamond Labs showed that fourth power scaling occurs at 4 MAs. "

This is the first I had heard of 4th power scaling. My understanding was that it scales with I^2 and then tapers of as power increases. In other words, power in is proportional to power out.

Could you post a reference as to the scaling at large currents? I would love to read up on it.

[guest]

Oh Yeah:

The University of Illinios IEC work Has the following quote:

" A steady - state IEC Engine is the easiest to design, because of complications of pulsed input/output power handling /conditioning are avoided.
Also most experimental data for IEC devices have been obtained in steady state operation. However to obtain a reasonable power balance , the steady state design requires the assumption of a optimistic scaling law. A more conservative scaling law (reaction rate proportional to i^3 ) is used in this updated pulse design. (** here is the kicker**)(This assumption should be contrasted to the present experimental data which show i^2 scaling at ion currents up to 0.2 amps The i^3 assumption is "consistant" with theory,
however which predicts a transition to i^3 scaling in the kA current range required for propulsion due to an enhanced core density associated with wave compression effects.)(1)

There are many texts that have this stuff look under plasma focus machines ...theory of operation .
A fast pulse capacitor book listed it under fusion equations.
IEEE has stuff on it under fusion.
Some modern physics texts have it as an appendix.
I believe Physics Today around the late seveties published a lot on the scaling law.
It should be referenced under Project Sherwood
The empirical formula came out of Vacuum Arc experiments of the DCX machines during the fifties.
See my post on the dcx machine in fusion history section.
The scylac experiment used high pulse current for fusion... that reference was used a lot.

This scaling law has no top end... it has only been tested in certain ranges..... I made another post about scaling laws today .. you might find it interesting.

(1)
G. H. Miley, A,J Satsangi, J. Demora, J.B. Javedani,Y. Gu,R.L. Burton and H Nakashima
Fusion Studies Laboratory, Urbana Illinois

Inovative Technology for an Inertial Electrostatic Fusion propulsion Unit

Paper 94-3321 aiaa/asme/sae/asee joint propulsion conference june 27-29 1994 American Institute of Aeronautics and Astronautics Inc.

Larry Leins
Physics Teacher

[jim-frank]

Has anyone done the calculation on how long it takes an ion to travel from the outer grid to the inner grid of a typical fusor- i.e., about 6 or 8 inches of total path length? I am curious about the pulse characteristics that will work for pulsed D-D fusion. Thanks. Jim Frank

[guest]

I've been working on that very thing.
I will have that post in the next three days on 01/10/02
I think you'll find my next pulse fusor to be very interesting.

Larry Leins
Physics Teacher