Plasmagun/railgun for Stelarate

For the design and construction details of ion guns, necessary for more advanced designs and lower vacuums.
Jonathan Schilling
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Real name: Jonathan Schilling

Re: Plasmagun/railgun for Stelarate

Post by Jonathan Schilling »

Hi Andrew,

please do not get me wrong about the following:
I am very happy having found this forum where other people are actively working in experimental physics
and greatly encourage anybody to stay in the field and widen his/her experiences.

However, having a look at your setup reminds me in some sense of the following guys from the Ukraine:
https://www.youtube.com/watch?v=g545WaMZ4oA

Indeed, their experiments "work" as well, but please do me the favour to invest at least into some quality wiring
of all the HT capacitors and stuff. Not only for the reason of getting rid of corona discharges at every sharp edge...

Have a nice evening,
Jonathan
Andrew Haynes
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Real name: Andrew Haynes

Re: Plasmagun/railgun for Stelarate

Post by Andrew Haynes »

Ha, on the semi permanent stuff I've splash electrical tape, good to 800v. I'll probable hot glue the exposed wire when I think I'm not going to change or add to that part.

Spark gap distance = 8 mm
Inductor coil = 3.3mH
Inductor capacitor storage = 2.5nF
Capacitor bank = 2uF
Capacitor voltage = 8.8kv

Run
mV......Joules
2.5......1.56-8
0.8......1.6-9
0.2......1-10
0.2.......1-10
0.6.......9-10
1.8.......8.1-9
0.2.......1-10
0.8.......1.6-9
1.5.......5.6-9
1.6.......6.4-9

Average 1.02mV

Cheers
Andrew Haynes
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Dennis P Brown
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Re: Plasmagun/railgun for Stelarate

Post by Dennis P Brown »

Again, I do not speak for the forum but frankly, I am totally lost why you are posting raw data from experiments unrelated to fusor's; worse, posting a string of data isn't what experimenter's are expected to do at sites since this isn't a data archive site; nor, for that matter, does it make the slightest sense to me relative to ion guns or what you hope to show/determine. In my opinion, you should only post research conclusions for experiments. In general, most people involved with research science, is that when they have conducted a series of experiments, they FIRST crunch the data into a properly summarized form, use this in standard or their special models and PUT IT INTO CONTEXT relative to the experiment. Then they post those conclusions.
Andrew Haynes
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Re: Plasmagun/railgun for Stelarate

Post by Andrew Haynes »

Point taken, a question, I'm basing my experiment around this formula
Fx = jy*Bz = k(Ey - vx*Bz)Bz = k*Bz^2(Ey/Bz - vs)
It's a modified lorentz force for the acceleration of plasma by current and magnetic fields. The formula gives say a result 10newtons, but it obviously doesn't move air that much, I'm assuming that the force is contained in the arc, which would explain the fact the arc wants to form as far away as possible from the magnetic.
What values would a arc be in the sense of physical size, and is there a formula that can be used to produce a approximate of size based on current,gas pressure,and length.
Thanks
Andrew Haynes
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Dennis P Brown
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Re: Plasmagun/railgun for Stelarate

Post by Dennis P Brown »

Your statement about "containing" the Lorentz Force demonstrates you have no understanding of what that force means much less what you seem to be trying to achieve. The force is ONLY felt by charged particles via magnetic and electric fields hence, containment does not mean what you imply; also, air (unless ionized) will feel no net force by that mechanism. In any case, with the trivial voltage and current levels you have, all the force you will really see is the heated over pressure from the air from the arc. If you want to study the effects of the Lorentz force on plasma's, then you really need to have your system in a vacuum to get clear results.
Andrew Haynes
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Real name: Andrew Haynes

Re: Plasmagun/railgun for Stelarate

Post by Andrew Haynes »

For the area around the electrodes only charged air ions and free electrons will be the only things that will experience the force, this force will only effect the plasma that is contained in the arc.
But the question is there any data or formula that predict the thickness of the arc at different gas pressures and current?
Type of off topic but 12v,1a is enough to produce noticeable result with salt water, because the force is over the volume, the reason why I asked the question is that the volume of a arc at atm is small, hence I want to see the ballpark to aim for.
To help study it's effect at atm pressure, I was going to use a chemical reaction to raise the tempture up to 2000-3000K and instead of a solid state switch, send the 1% plasma charge density as a ball,blob,pulse or lump pass the sparkgaps
Andrew Haynes
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Dennis P Brown
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Re: Plasmagun/railgun for Stelarate

Post by Dennis P Brown »

An air arc is a very complex affair - issues of current pressure, water vapor, condition of your circuit, electrodes and many other issues will cause the arc core to vary. Try searching via google and read any technical papers on the subject relative to arc size/diameter. That isn't a topic I'd think is amiable to calculation using straightforward equations - you will have to do the experiments and measure those parameters, if you need them.
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