Plasmagun/railgun for Stelarate

For the design and construction details of ion guns, necessary for more advanced designs and lower vacuums.

Plasmagun/railgun for Stelarate

Postby Andrew Haynes » Mon Jan 09, 2017 6:25 am

I thought it might be interesting to some members of the type of project. It's a stelarate which is a donut shaped device. Plasma flows around the ring creating a circulating current.

At the moment I'm working on the plasma injector. The final goal is a plasma velocity in the 3km/sec range. I'm slowly building up the capacitor bank over a year.
The Nst with a capacitor divide(1mA), gets changed to dc by the bridge to 9kv max, depending on the spark gap distance.

The Al projectile plan is to force it down a tube with compressed deuterium.

Heat of fusion 395.6kJ/kg
Specific heat 0.897.5kJ/kg/k
Heat of evaporation 10,497kJ/kg

The pallet will be about 1-4gram at 13.3kJ/gram
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Re: Plasmagun/railgun for Stelarate

Postby RobertTubbs » Wed Jan 11, 2017 4:36 am

When you fire your railgun into your plasma toroid please remember to post pictures of the final results.

Thank you,
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Re: Plasmagun/railgun for Stelarate

Postby Frank Sanns » Wed Jan 11, 2017 6:11 am

You might want to recheck your energy equations. For fusion, deuterium needs to be accelerated to around 0.1 c. (3E5 m/sec). KE-0.5mv^2. A 1 gram pellet would be 0.5*0.001*(3E5^2) or 45 mega joules. Rail guns are not very efficient so you would need many times that number for your desired velocity. You could cut your pellet size down to a milligram then you would only need a few mega joules to do the job.
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Re: Plasmagun/railgun for Stelarate

Postby Andrew Haynes » Wed Jan 11, 2017 7:58 am

@Robert Tubbs.
I was planning to ,too see how the plasma reacts. After I get enough caps to make aluminium vapour a second spark gap will heat up the gas, and accelerate it fast.
Still working out how to make the plasma stay in the torrid , if it's anything like a plasma cutter, the chamber might not last.

@Frank Sanns
It's mainly to look at plasma, with current self generated. I'm looking at more pressure and tempture, but the values will probably be beyond my reach.
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Re: Plasmagun/railgun for Stelarate

Postby Dennis P Brown » Sat Jan 14, 2017 4:37 pm

A difficult project but very interesting approach. Do post as you can. Also, be very careful - cap banks are very dangerous at even moderate voltages. Consider bleed resistors and always assume they are charged - so, use a safety shorting stick to check that they are discharged before servicing.
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Re: Plasmagun/railgun for Stelarate

Postby Andrew Haynes » Sat Jan 21, 2017 1:23 am

@Dennis P Brown
Good idea, I normally disconnect the power supply a use insulated pliers to short a capacitor bank with a wire, then tie it together while I work on the circuit.
Microwave oven capacitor have a internal 10Mohm bleeder resistor, it saved me have a voltage balancer network.
I,ve had some more capacity to the bank, I get about 4 a week. I've add a top and bottom magnetic, now the pellet notice ly moves but still not far.
After I get half the secondly layer brought I will work on a test to use potassium carbonate when heated to 800-900C breaks down into CO2,K+,KO, hopeful the ion will breakdown the spark gap.
Attachments
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Re: Plasmagun/railgun for Stelarate

Postby Andrew Haynes » Sat Jan 28, 2017 8:10 pm

Tested the ions the morning, it easily breaks down the gap, with the pulse A lot quicker. I can't get any picture's from the videos, it's just a white screen.
The spark gap was at 10mm, just a little bet of vapours was enough to arc.
Attachments
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After the white screen
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Before the white screen
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Re: Plasmagun/railgun for Stelarate

Postby Dennis P Brown » Mon Jan 30, 2017 8:49 pm

Air arc's are fun and games but not indicative of anything relative to overall power, voltage or current except in a very indirect manner. If your objective is pulse power in a plasma, with a goal of deuterium ions, then a vacuum system should be your goal, I'd think. A rail gun in air will never work for the velocities you will need to create a small bit of fusion.

We have already, in our lab, caused a solid target of deuterated plastic to achieve 1000 km/sec and then collide with a stationary deuterated target (each much less than a 0.1 milli-gm.) This resulted/achieved a few million neutrons. Not exactly a useful method but it did test the idea ... the driver was a 2500 J laser pulse (delivered over 1.8 nano-sec). Not easy to create ...lol.
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Re: Plasmagun/railgun for Stelarate

Postby Rex Allers » Mon Jan 30, 2017 11:29 pm

Andrew,

I'm a bit concerned about the way you seem to be manipulating your high voltages. I would never trust the plastic-coated handles of normal pliers to manipulate multi-kilovolt conductors and they even look to be rather small pliers. Please consider getting some kind of long plastic rod or tube with no metal inside to do things like moving your gap or grounding the caps. This requires some thought about how to arrange things mechanically since you won't have the convenience of pliers to grip random things, but with a little thought I think you can find a much safer method than what you seem to have now.

Also, your wiring looks pretty open, loose and haphazard. Is it insulated for well more than the kVs you are putting through it? It doesn't really have to be if it is within an well insulated or grounded container but I'm not sure I am seeing any of this. If nothing else, the HV wires should be neat and secured so they couldn't flop into a dangerous position if something comes loose.

Good luck on your project, but please give safety your greatest attention.
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Re: Plasmagun/railgun for Stelarate

Postby Richard Hull » Tue Jan 31, 2017 8:49 am

Rex is right. I worked with a water arc gun doing dielectric explosions for a while and the peak currents were on the order of 50,000 amps. You have to have short stout connections for this work if high peak energy is needed. That kind of fast pulse work is all surface currents and amperian forces are fearsome. You only get one mistake and you are gone.

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Fusion is the energy of the future....and it always will be
Retired now...Doing only what I want and not what I should...every day is a saturday.
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