Search found 78 matches

by prestonbarrows
Sat Aug 04, 2018 12:13 am
Forum: Design
Topic: Sintered metal objects from a standard FDM 3D printer
Replies: 3
Views: 10483

Re: Sintered metal objects from a standard FDM 3D printer

At scales to be at all relevant, say, 12" cube width and above, plain old machining is practical and cheap. Porous, sintered messes based on plastics will be dimensionally unstable and a horror show under vacuum.
by prestonbarrows
Thu Dec 29, 2016 5:20 am
Forum: Theory
Topic: What is a convex magnetic field?
Replies: 4
Views: 10286

Re: What is a convex magnetic field?

The notion of 'convex magnetic fields being stable' arises more clearly from MHD and fluid dynamics than single particle motions. At the temperatures, densities, and field strengths relevant to a reactor, we can think of the gyroradii as negligibly small and the plasma being a fluid that is 'locked'...
by prestonbarrows
Thu Feb 04, 2016 12:37 am
Forum: News
Topic: Wendelstein 7-X
Replies: 50
Views: 45915

Re: Wendelstein 7-X

this article claims Wenderlstein 7X was the first in the world ever to produce hydrogen plasma? Other fusion prototypes only produced helium plasma. Is there any veracity to that? No. That is just a really horrible article. Here is a much better one directly from the source. http://www.ipp.mpg.de/4...
by prestonbarrows
Sun Jan 24, 2016 4:14 pm
Forum: Theory
Topic: Loss of potential well in corner cusps
Replies: 7
Views: 8679

Re: Loss of potential well in corner cusps

D Tibbets wrote:Dr Parks has reported that having a positive charge on the magrid results in the potential well- negative space charge droping to zero in the corner cusp areas.


Source?
by prestonbarrows
Sat Dec 12, 2015 5:58 am
Forum: News
Topic: Wendelstein 7-X
Replies: 50
Views: 45915

Re: Wendelstein 7-X

Fusion reactors are all about getting particles hot enough and keeping them around long enough to react. The magnetic component of the Lorentz force bends moving charged particles into circular orbits. If the magnetic field is strong enough, you end up with very tight helical orbits where the partic...
by prestonbarrows
Wed Aug 05, 2015 2:50 am
Forum: News
Topic: PPPL Colloquium: The Lockheed Martin CFR, Aug 6, 2015
Replies: 34
Views: 11507

Re: PPPL Colloquium: The Lockheed Martin CFR, Aug 6, 2015

If they livecast it, someone please post the link and/or capture it.
by prestonbarrows
Wed Jul 08, 2015 2:30 am
Forum: News
Topic: JET will attempt Q-record by the end of the decade
Replies: 24
Views: 12656

Re: JET will attempt Q-record by the end of the decade

ITER will hopefully come online sometime during the next decade . Almost impossible within next decade. As a preface, let me say that I think the current fusion programs in the US/world are extremely worthwhile ideas. Unfortunately, most of the news coming out of ITER the past number of years has b...
by prestonbarrows
Sun Jul 05, 2015 4:36 am
Forum: News
Topic: JET will attempt Q-record by the end of the decade
Replies: 24
Views: 12656

Re: JET will attempt Q-record by the end of the decade

Another question is what are they changing from previous tests. Higher temperatures, higher B fields, better control of edge instabilities, Beta pushed a little further.... ? Do they hope to reach ignition ? JET still holds the record for experimental Q; this required the use of D-T and was set way...
by prestonbarrows
Sat Jul 04, 2015 3:49 pm
Forum: Design
Topic: new copper composite
Replies: 19
Views: 15162

Re: new copper composite

In a commercially pulsed machine, getting rid of heat would still a huge factor as the pulses are going to be in very rapid succession? The extreme pulsed magnets I mentioned earlier are only really used for single shots or extremely low duty cycles. They are usually used for things like magnetic p...
by prestonbarrows
Sat Jul 04, 2015 3:49 am
Forum: Design
Topic: new copper composite
Replies: 19
Views: 15162

Re: new copper composite

PS: I don't know the limits of copper. When transformer windings, electromagnet windings, etc. are chosen, given a certain quality of copper wire, are the engineers limited more by global heat isues or by local limitations where these defects/ contaminates/ choke points occur? Generally, big resist...
by prestonbarrows
Sun Mar 29, 2015 12:07 am
Forum: Theory
Topic: Diagmagnetic plasmas' resistivity Vrs Electrical resistivity
Replies: 3
Views: 2489

Re: Diagmagnetic plasmas' resistivity Vrs Electrical resisti

I am not sure what you mean by 'magnetic resistivity'. But to expound a bit about magnetized plasma... I am not very familiar with the mathematics of non-thermal plasmas so some of the following might not hold true is this case. But, for tokamak-like thermal plasmas, to first order (neglecting insta...
by prestonbarrows
Sat Dec 27, 2014 6:06 pm
Forum: General
Topic: Accelerator-driven sub-critical reactor
Replies: 15
Views: 2683

Re: Accelerator-driven sub-critical reactor

BTW I thought particle accelerators were kind of inefficient.. how efficient are they really? Electrically, DC particle accelerators are basically just like running current through a resistor (a current running from a higher voltage to ground). The electrical efficiency is basically just limited by...
by prestonbarrows
Mon Dec 22, 2014 9:39 pm
Forum: News
Topic: Mach Effect progress
Replies: 2668
Views: 670627

Re: Mach Effect progress

He wants to see something useful. As someone who has basically only glanced over the wikipedia page for this: It seems like the three main possibilities are 1) they are missing something in the math/science and the whole idea flops 2) their theory is correct and works in the real world but has scal...
by prestonbarrows
Thu Dec 18, 2014 2:03 am
Forum: Theory
Topic: simple particle simulators
Replies: 21
Views: 14057

Re: simple particle simulators

asdfuogh wrote:There is not enough computational power to do the whole range of time scales and length scales at the same time..


Image
by prestonbarrows
Thu Dec 18, 2014 12:15 am
Forum: Theory
Topic: Can anyone walk me through Field Reverse Configurations?
Replies: 23
Views: 10001

Re: Can anyone walk me through Field Reverse Configurations?

http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.105.045003 Millisecond range, actually. Use that article as a starting point to find more. Thanks for the link. Just to note, the pulsed formation/translation stage is 10's of microseconds while the lifetime of the combined FRC after the two ...

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