Archived - My first (almost) perfect star!

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JRizzardi
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Archived - My first (almost) perfect star!

Post by JRizzardi » Wed Dec 19, 2012 6:28 am

Got what i consider to be almost perfect star mode in my demo fusor!!
https://www.youtube.com/watch?v=dKizlxBRyFE
You really get to see almost exactly how it looks about 50 seconds in.

and my first (actually second, but this was longer, better, and didnt have me screaming for joy) light

https://www.youtube.com/watch?v=ihWaY1gz388

the black forming on the glass is (i think) from some putty im using to hold my inner grid in at the side. either that, or pump oil that got in the jar earlier.
It gets annoying at the best part unfortunately...

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Frank Sanns
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Re: My first (almost) perfect star!

Post by Frank Sanns » Wed Dec 19, 2012 2:46 pm

Congratulations on the plasma but this is not star mode. The first video shows a bugle jet. The second one not even that. This is just typical plasma glow at higher pressures than star mode.

In just about all cases, a simple two stage mechanical pump alone will not get you down to low enough pressures for star mode. It has been done including fusion with just a pump but it is by far the exception than the rule.

Frank Sanns

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Doug Coulter
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Re: My first (almost) perfect star!

Post by Doug Coulter » Wed Dec 19, 2012 3:19 pm

This should be plasma club material, but no, you're not getting a star. I'd have to guess that you are about at 10 times the pressure needed to see that - I've taken pressure sweeps, and that bugle happens somewhere around 10-40 times the pressure you have to get down to in order to get a distinct poisser and rays.
http://www.youtube.com/watch?v=Sb3x2yPFcB8
is one of those (check DCFusor's channel, about a year ago, for more).

FWIW, I've never seen good rays or fusion with a spiral grid, which I've tried in several designs and sizes.

Bottom line, Frank is right. Don't be discouraged - but also, don't expect to get much better results than anyone else using the same gear - you're on-track for what you are using, you just need better vacuum and a better grid - just like everyone else has.

Edit: here's a bugle with a "real" pressure reading, subject to the known issues with pure D and my particular gage (pkr-251) which reads a little high on light gasses. Factor of 10 better is what you need. http://www.youtube.com/watch?v=sY_jKJQUAlg
Why guess when you can know? Measure!

JRizzardi
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Re: My first (almost) perfect star!

Post by JRizzardi » Wed Dec 19, 2012 3:49 pm

well that would most definitely count toward suckage.I really thought I had something there. But I know the second one was nothing, that was just one of my first lights
So for now, I will most definitely change the grid. But because I am at such high pressure right now, would increasing the voltage do? or would that just cause un-needed radiation hazards?
And other than the bugle, what else exactly needs to change in order to get it?

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Re: My first (almost) perfect star!

Post by Tyler Christensen » Wed Dec 19, 2012 3:52 pm

More voltage isn't really possible due to the non-linear VI relationships in a plasma device. It'll draw many orders of magnitude more current if you were to turn up the voltage by an order of magnitude (surely more than your chamber or supply could ever support). There isn't really any way to get from your situation to starmode without a stronger vacuum.

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Re: My first (almost) perfect star!

Post by JRizzardi » Wed Dec 19, 2012 3:58 pm

that disappointing....
what exactly do you mean by "isnt really possible?" though
can you explain on that whole thing? im still an extreme novice

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Re: My first (almost) perfect star!

Post by Tyler Christensen » Wed Dec 19, 2012 4:02 pm

Basically, you run into a wall at a given pressure where more voltage requires much more than linearly more current.

There should be lots of discussions to search for on the forum regarding the relationship of voltage, pressure, and current, which are all related and all affect each other in a practical fusor scenario.

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Richard Hull
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Re: My first (almost) perfect star!

Post by Richard Hull » Wed Dec 19, 2012 4:04 pm

Bugles and clean jets appear at about 50 microns. They get skinnier and crisp with a perfect sherical central glow around 20 microns. Star mode just gets visible below 15 microns but is distinct with multiple rays in a near perfect geodesic grid below 10 microns.

What you have, at best, in your jar is about 70-100 microns.

Welcome to the plasma club.

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Chris Bradley
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Re: My first (almost) perfect star!

Post by Chris Bradley » Wed Dec 19, 2012 4:37 pm

Richard Hull wrote:
> Bugles and clean jets appear at about 50 microns. They get skinnier and crisp with a perfect sherical central glow around 20 microns. Star mode just gets visible below 15 microns but is distinct with multiple rays in a near perfect geodesic grid below 10 microns.
>
> What you have, at best, in your jar is about 70-100 microns.
I suspect higher still - the smaller the vessel, and the worse the electrical arrangements (viz. a glass jar, rather than a conducting vessel) makes these effects prevalent at higher pressures. Prob 100~500 microns.

Bottom line is - it's nothing to do with your voltage (looks like you are operating around the high-hundreds of volts here, but not yet into kV) nor grid. The limits of your system here are about the ultimate vacuum of your 'vacuum system'. I put it in inverted comments because what you have there barely qualifies as one - no disrespect to your work at all, in fact the opposite can be said and I am surprised that you have achieved even that level of vacuum with what you have, because it does appear to be in sub Torr range (just!) which is a surprisingly good effort from those parts!

Getting the right bits to create a much better system can be done on a small budget providing you keep a look-out for good, clean 2nd hand lab bits. and wait a while for them to come up. You have already surpassed what might be expected with the items you've currently assembled!

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Re: My first (almost) perfect star!

Post by JRizzardi » Wed Dec 19, 2012 5:17 pm

Alright, now im understanding more of this. Thank you all.

current progress:
http://www.youtube.com/watch?v=Hp_OHrbSzEU
http://www.youtube.com/watch?v=2w8EX8iPAWo
i took two because my camera simply just wouldnt focus...

is this at least a little better now that they get thin and are almost gone?

Richard -
that was very helpful, i will start looking for a new pump, but for now i guess this will hold me over to force myself to improve on what ive got.

Chris -
Wow. really? Didnt think that much! in no way do i take any disrespect to this. Everything here has been done with probably the bare minimum.. Plus, i would rather know what is really up with what ive been doing rather than it be sugar coded in any way.

Right now, im going to drill another jar and line the inside with some aluminum tape leaving just a small window opening.

I will also work on a new grid rather then just a spiral

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