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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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
Andrew Haynes
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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

Code: Select all

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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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
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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
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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.
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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
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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.
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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
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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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