Plasmagun/railgun for Stelarate

For the design and construction details of ion guns, necessary for more advanced designs and lower vacuums.
Andrew Haynes
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Plasmagun/railgun for Stelarate

Post by Andrew Haynes »

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

Post by RobertTubbs »

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

Thank you,
RT
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Re: Plasmagun/railgun for Stelarate

Post by Frank Sanns »

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.
Achiever's madness; when enough is still not enough. ---FS
We have to stop looking at the world through our physical eyes. The universe is NOT what we see. It is the quantum world that is real. The rest is just an electron illusion. ---FS
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Re: Plasmagun/railgun for Stelarate

Post by Andrew Haynes »

@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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Dennis P Brown
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Re: Plasmagun/railgun for Stelarate

Post by Dennis P Brown »

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

Post by Andrew Haynes »

@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.
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Re: Plasmagun/railgun for Stelarate

Post by Andrew Haynes »

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.
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Re: Plasmagun/railgun for Stelarate

Post by Dennis P Brown »

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

Post by Rex Allers »

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

Post by Richard Hull »

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.

Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
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Re: Plasmagun/railgun for Stelarate

Post by Andrew Haynes »

@Dennis P Brown
The idea is to have a 10 turn coil about 500*200mm, made of steel pipe 10mm Id with 16mm Od, at each turn a spark gap and magnetic .
I'm not sure of the induction but if I can get a couple thousand amps flowing throughout the plasma would be good.
The pulse should get to 20000K increase the meanfreepath and at the same time lower the resistance.

@Rex Allers and Richard Hall
Being working on the safety and capacity, the picture below is abit better, plan to solder the connections just need a 100watt iron, and electrical tape it up.
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Re: Plasmagun/railgun for Stelarate

Post by Dennis P Brown »

As I posted before and as others are now indicating, a safe "shorting stick" is very important to both check that the system is safe (fully discharged) and to enable you to discharge the system in the event of an emergency. That is, a long plastic stick with a metal end (metal screw or pointed rod) with a fairly high current (proper gauge) well insulated (for the voltage) wire connected from that tip to a ground (the same used for the cap bank is fine as long as it has been checked - i.e. is a good ground.) I have one of these for both my fusor and accelerator (its voltage multiplier.) I never touch any part of these systems without first checking them with the ground stick.

Another important safety issue - caps that are rapidly discharged can over heat and explode. Shielding and proper safety eye wear is essential, too.

Those exposed rails on those banks are death traps just waiting to happen and you will very much need some type of stand off shielding for those rails if I am reading your picture correctly.

I see no issues with you getting a plasma in the 20,000 K range at a few hundred amps for a fraction of a second; that said, the ability to accelerate deuterium to any type of significant fusing velocities will not be achieved with such little power and low voltage (building a small accelerator would do far better.) Even a high end neutron detector system would not measure any signal with such a low velocity plasma. However, you are mistaken if you think an atmospheric system will support a plasma that allows increased "mean free path". Sorry, but the only way to change that parameter is to significantly lower the pressure (in the range of 10^-3 torr or more.)

You have some good experience with caps so a voltage multiplier shouldn't be too difficult (getting a 50 kV, high current (for a small fraction of a second) system isn't hard to build (but isn't cheap, however, unless one gets a good deal on the caps but that is another issue.)) The very high vacuum system is another matter and may not interest you for a small accelerator so that might not be for you; however, that, in essence is what you appear (from my read) to be attempting to achieve - accelerate deuterium - with this current system. That will not work at all with such a low voltage much less at atmospheric pressure.
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Re: Plasmagun/railgun for Stelarate

Post by John Futter »

At least you are using micrpwave oven capacitors that have an in built high value shorting resistor
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Re: Plasmagun/railgun for Stelarate

Post by Andrew Haynes »

Hi, I entered the data on hyperphysic website for the mean free path, at standard temperature compared to 20kK was a 100 magnitude longer, lowering to 1kPa at the outlet, should get the length enough, with the voltage drop around the coil ,parallel, should or maybe accelerate it enough.
I don't want to make 50kv, or 220kv.
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Re: Plasmagun/railgun for Stelarate

Post by Dennis P Brown »

You do realize that the room temperature mean free path is on the order of a nano-meter so increasing it by just two orders of magnitude isn't very much - 100 nm isn't very significant - and really, since the plasma temp isn't uniform (only a very narrow region reaches those temps), your average ion mean-free path is going to be much shorter. So, what do you think will be the result of your atmospheric (atm) pressure arc in air will achieve?

Aside: Don't use such an arc in hydrogen/deuterium gas at atm pressure! This class of gas is very explosive if oxygen is present in any moderate to even minor amounts (as for arcing H2/D2 in the atmosphere, that could prove highly dangerous for even small amounts of gas! Also, H2/D2 burns with nearly an invisible flame.) Also, even in pure H2/D2 a dangerous over pressure can occur in a sealed container by reactions and also from the temp induce pressure spike of an arc. In a fusor the pressure is 10-6 atm so D2/H2 isn't gonna create problems (and the trace oxygen levels are far lower still.) DO NOT ever expose H2/D2 at or anywhere near atm pressure with arcs!

Have fun but do remember safety is paramount.
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Re: Plasmagun/railgun for Stelarate

Post by Andrew Haynes »

This is the prototype that I will be using.
Data

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H value ????
Volts.     uF.      Bv.       Nogap       vp
?            1.5a.    9kv.      1.              1 m/sec,a


a = approx.

Things I noticed, potassium ion are quite conductive. There's a lot of back pressure in a pipe. With a magnetic the positive ion travel one direction compared to electrons, that's different from salt water.
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Re: Plasmagun/railgun for Stelarate

Post by Dennis P Brown »

Ion flow in water does not create much 'separation' of said ions; this is covered very well in any physical chemistry book (see this exact subject, in fact.) Also, what does this project have to do with a fusor site? Plasma arc's in air have a slight relevance but wet chemistry is a bit off-topic (your mention of "salt water' and using plastic(!?) tubing.) I am NOT saying don't post at all but I'd personally would like to see some justification and explanation on what you are doing relative to fusor related fusion (i.e. for instance, does this relate to cold fusion, maybe?) Otherwise, I am lost on addressing your posts or understanding your end goal or even your experiment.
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Re: Plasmagun/railgun for Stelarate

Post by Andrew Haynes »

A range of areas, the energy stored in a magnetic field with reconnection events, self generated current and the accompanying magnetic field of plasma that has velocity. The effects of plasma and magnetic field with a imputed voltage source.
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Re: Plasmagun/railgun for Stelarate

Post by Richard Hull »

All that is rather cryptic and jumbled. What instruments do you have on hand to investigate and record the specific data you are seeking?

Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
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Re: Plasmagun/railgun for Stelarate

Post by Andrew Haynes »

I was slowly getting that ready, after a post with different DMM readings of a copper wire around the tube(which is going to be replaced with a more substantially inductor, i'm slowly getting to a whole heap of things), with enough data to make theory of operation, I was going to ask what measurement equipment to get.
Was thinking a hall sensor, some Watt/power device.
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Re: Plasmagun/railgun for Stelarate

Post by Dennis P Brown »

A few issues and nomenclature: first off, there is no such thing as a "self generated current". I assume you mean an induced current.

All plasma's have a velocity component - I assume you mean a plasma that you will force to have a 'net' direction by some of the ions(?) Plasma's don't induce an external magnetic field unless they have a net direction via a net current component.

A watt/power device - simply use the standard formula for power; you have current, time and voltage.

Magnetic Reconnection is a 'hot' topic in theoretical physics because it is so poorly understood. One of the few 'easy' ways to study it directly is by satellites located around the Earth. Requires very advance equipment and powerful fields to attempt in a laboratory environment. That is a tall order. Also, one needs a very strong plasma physics background to approach this subject in a realistic manner.

That all said, what you have so far explained is hardly a topic that belongs in the "Ion Gun" forum and is rather disconnected relative to fusors. Also, I still don't understand what you are trying to achieve and how it relates to the topic of fusion. Sorry, not trying to be a pain but I am really lost on this point.
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Re: Plasmagun/railgun for Stelarate

Post by Andrew Haynes »

The picture below is what I'm trying to create over the coming months. A chemical reaction creates ionized gas flow, that goes down a electrical insulation tube, spark gap fire to keep and increase the charge density, a radial magnetic field is created that cuts at right angles to copper wire inductor.
The device might be a coil instead of straight, and maybe other arranges will show themselves further down the track.
The ionized gas will be a pulse or blob, with the theory that the electron drift velocity in one km/sec will be faster than copper.
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Re: Plasmagun/railgun for Stelarate

Post by Dennis P Brown »

Ok; thanks. That does help clarify what you are getting at. That is a lot to achieve.

When you mean 'chemical reaction", I assume you are "burning" very small quantities of deuterium gas? If so, be extremely careful. That stuff is highly explosive in most mixtures of air and any significant accumulation can result in a very bad day.

Creating "plasma balls" is an extremely difficult art and has killed professionals so be very careful. And I have watched (but warned them not to try the experiment) as someone created such a plasma ball using a capacitor bank. They were too close and the plasma ball touched their hand. They were thrown across the room. They survived but learned a hard lesson.
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Re: Plasmagun/railgun for Stelarate

Post by Andrew Haynes »

I've built a test rig, which I will be getting all my data from. I'll be only making small changes to it.
So far a 2.0uF bank is discharge across approx 10mm spark gap. The voltage from the multimeter which is coming from 3 turn of wire around the plastic tube, is fluctuating around 3-4mV, when the gap fires it increases to 4-6mV.
After repeated fires both measurements drop to 1-2,2-4 respectful.
I think the drop might be caused by a build up of charge inside the tube, lowering the break over voltage, making less current pulse.
Will be doing some tests with magnetic next to the spark gap, and plan to tape up the pick coil etc.
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Re: Plasmagun/railgun for Stelarate

Post by Andrew Haynes »

Increasing the cap bank made the NST pack up, built this power supply from a MOT and voltage tripler. The noise on the multimeter is belay reading but ever now and then I get a decent reading.
The multimeter takes samples about twice a second, I'm missing the spike, I will try to build this peak detector.

Cheers
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