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EMC2 has published a polywell preprint on arXiv

Posted: Thu Jun 05, 2014 8:46 pm
by crowberry
EMC2 has published this polywell preprint on arXiv:

High Energy Electron Confinement in a Magnetic Cusp Configuration
Jaeyoung Park, Nicholas A. Krall, Paul E. Sieck, Dustin T. Offermann, Michael Skillicorn, Andrew Sanchez, Kevin Davis, Eric Alderson, Giovanni Lapenta


We report experimental results validating the concept that plasma confinement is enhanced in a magnetic cusp configuration when beta (plasma pressure/magnetic field pressure) is order of unity. This enhancement is required for a fusion power reactor based on cusp confinement to be feasible. The magnetic cusp configuration possesses a critical advantage: the plasma is stable to large scale perturbations. However, early work indicated that plasma loss rates in a reactor based on a cusp configuration were too large for net power production. Grad and others theorized that at high beta a sharp boundary would form between the plasma and the magnetic field, leading to substantially smaller loss rates. The current experiment validates this theoretical conjecture for the first time and represents critical progress toward the Polywell fusion concept which combines a high beta cusp configuration with an electrostatic fusion for a compact, economical, power-producing nuclear fusion reactor.


The present experimental result is a major step toward a Polywell fusion reactor in that it validates the conjecture that high energy electron confinement is improved in a high β plasma. However, two additional measurements are needed to estimate the performance of a Polywell fusion reactor. The first is to quantitatively determine the loss rate. The second is to measure the efficiency of ion acceleration by electron beam injection.


CONCLUSIONS
In summary, the present experimental results demonstrate for the first time that high β plasma operation can dramatically improve high energy electron confinement in the magnetic cusp system. This result validates the central premise of the Polywell fusion concept which uses high energy beam injected electrons to create an electrostatic potential well for ion acceleration and confinement. The current plan is to extend the present work with increased electron beam power to sustain the high β plasma state and to form an electrostatic well. If the deep potential well can be formed and the scaling of the electron beam confinement is found to be favourable, as conjectured by Grad and others, it may be possible to construct a compact, low cost, high β fusion power reactor based on the Polywell concept.


The URL to the paper is http://arxiv.org/abs/1406.0133.
Together with the paper there are five animations also.

It is very interesting to finally see a paper by EMC2 on their work. It is also interesting to see that the polywell is considered a viable alternative for an reactor, but much work (and funding) is of course needed to go forward with the concept.

Re: EMC2 has published a polywell preprint on arXiv

Posted: Thu Jun 05, 2014 10:35 pm
by ckrucks
Good.

Re: EMC2 has published a polywell preprint on arXiv

Posted: Thu Jun 05, 2014 11:09 pm
by Torulf2
It has been a long wait.

Re: EMC2 has published a polywell preprint on arXiv

Posted: Fri Jun 06, 2014 12:09 am
by paperburn1
where do we go from here???????

Re: EMC2 has published a polywell preprint on arXiv

Posted: Fri Jun 06, 2014 3:14 am
by Stubby
paperburn1 wrote:where do we go from here???????


To the moon Alice, right to the moon.

Re: EMC2 has published a polywell preprint on arXiv

Posted: Fri Jun 06, 2014 3:35 am
by jgarry
So fusion is no longer twenty years down the road?

Re: EMC2 has published a polywell preprint on arXiv

Posted: Fri Jun 06, 2014 3:43 am
by bennmann
I am cursing in happiness. Christmas? In June?

I invite everyone to partake in a a little of your favorite drink across the globe. This is the paper I've been waiting for since I started watching this thing years and years ago.



Image
Dr Park, Dr Nebel, thank you. Now all we need is a room temperature super conductor to make some really neat small designs.

But now I don't know if I want to donate to Focus Fusion on IndieGoGo next paycheck....

EDIT: Added a screen grab of the WB8.1 pic from the paper

Re: EMC2 has published a polywell preprint on arXiv

Posted: Fri Jun 06, 2014 5:06 am
by Aero
From the preprint:

The magnetic cusp experiments described in this paper
were conducted in a cubic vacuum chamber measuring
45 cm on an edge. Centred in this chamber are six iden-
tical magnet coils, each coil having major radius 6.9 cm
and minor radius 1.3 cm. The coils are arranged such
that each coil is centered on a face of a cube measuring
21.6 cm on an edge as shown in Figure 2, producing cusp
magnetic field. Each coil is driven by its own battery
powered system capable of generating a static magnetic
field from 0.6 kG to 2.7 kG at the cusp near the coil cen-
ter with coil currents between 5-22 kA turns. The coils
are energized for pulse duration of 40 ms compared to the
100 (microsecond) plasma duration, thus generating static magnetic
field during the time of interest.


Isn't that a lot smaller than the WB-6 and WB-7 machines? Or am I confusing 15 cm "diameter" for those machines?

Re: EMC2 has published a polywell preprint on arXiv

Posted: Fri Jun 06, 2014 5:49 am
by choff
From the numbering scheme I get over 15000 test shots, no show stoppers mentioned.

Re: EMC2 has published a polywell preprint on arXiv

Posted: Fri Jun 06, 2014 6:41 am
by djolds1
crowberry wrote:EMC2 has published this polywell preprint on arXiv:

High Energy Electron Confinement in a Magnetic Cusp Configuration
Jaeyoung Park, Nicholas A. Krall, Paul E. Sieck, Dustin T. Offermann, Michael Skillicorn, Andrew Sanchez, Kevin Davis, Eric Alderson, Giovanni Lapenta


We report experimental results validating the concept that plasma confinement is enhanced in a magnetic cusp configuration when beta (plasma pressure/magnetic field pressure) is order of unity. This enhancement is required for a fusion power reactor based on cusp confinement to be feasible. The magnetic cusp configuration possesses a critical advantage: the plasma is stable to large scale perturbations. However, early work indicated that plasma loss rates in a reactor based on a cusp configuration were too large for net power production. Grad and others theorized that at high beta a sharp boundary would form between the plasma and the magnetic field, leading to substantially smaller loss rates. The current experiment validates this theoretical conjecture for the first time and represents critical progress toward the Polywell fusion concept which combines a high beta cusp configuration with an electrostatic fusion for a compact, economical, power-producing nuclear fusion reactor.


The present experimental result is a major step toward a Polywell fusion reactor in that it validates the conjecture that high energy electron confinement is improved in a high β plasma. However, two additional measurements are needed to estimate the performance of a Polywell fusion reactor. The first is to quantitatively determine the loss rate. The second is to measure the efficiency of ion acceleration by electron beam injection.


CONCLUSIONS
In summary, the present experimental results demonstrate for the first time that high β plasma operation can dramatically improve high energy electron confinement in the magnetic cusp system. This result validates the central premise of the Polywell fusion concept which uses high energy beam injected electrons to create an electrostatic potential well for ion acceleration and confinement. The current plan is to extend the present work with increased electron beam power to sustain the high β plasma state and to form an electrostatic well. If the deep potential well can be formed and the scaling of the electron beam confinement is found to be favourable, as conjectured by Grad and others, it may be possible to construct a compact, low cost, high β fusion power reactor based on the Polywell concept.


The URL to the paper is http://arxiv.org/abs/1406.0133.
Together with the paper there are five animations also.

It is very interesting to finally see a paper by EMC2 on their work. It is also interesting to see that the polywell is considered a viable alternative for an reactor, but much work (and funding) is of course needed to go forward with the concept.
Polywell returns. darn if it didn't take long enough.

Re: EMC2 has published a polywell preprint on arXiv

Posted: Fri Jun 06, 2014 8:46 am
by analysis
I just scanned the paper. They do not mention neutron measuring, nor actually fusion rates. :?

Re: EMC2 has published a polywell preprint on arXiv

Posted: Fri Jun 06, 2014 8:49 am
by Ivy Matt
Certainly a breath of fresh air after so long without real news. Still I have mixed feelings. The high beta plasma confinement results are encouraging, and reason for optimism. On the other hand, we were hoping for data on loss scaling, and we're still waiting. The talk about increased electron power gives me the impression that the data this paper is based on is several years old, but at least it's newer than the WB-7.1 results we wanted released. Mention of D-T fusion is a bit discouraging. Has EMC2 given up on D-D and p-B11? I get the feeling they're going to go for a D-T (or possibly D-D) demonstration reactor before they think about trying p-B11. However, they may just be demonstrating caution in their published papers.

I believe the device in the picture is WB-8.0. I'm not certain there's going be a WB-8.1, though it would be nice.

And fusion is always twenty (or thirty, or fifty) years down the road until you pass it by and see it in your rearview mirror.

Re: EMC2 has published a polywell preprint on arXiv

Posted: Fri Jun 06, 2014 12:23 pm
by ladajo
EMC2 built a smaller unit after WB8 to test and develop the startup cycle. That is what this paper is about.


In summary, the present experimental results demonstrate for the first time that high β plasma operation can dramatically improve high energy electron confinement in the magnetic cusp system. This result validates the central premise of the Polywell fusion concept which uses high energy beam injected electrons to create an electrostatic potential well for ion acceleration and confinement. The current plan is to extend the present work with increased electron beam power to sustain the high β plasma state and to form an electrostatic well. If the deep potential well can be formed and the scaling of the electron beam confinement is found to be favourable, as conjectured by Grad and others, it may be possible to construct a compact, low cost, high β fusion power reactor based on the Polywell concept.


This is Wiffleball boys & girls.

Next is to go back to WB8 and check for electron injection efficiency (Ie. document loss rates and loss rate scaling) and corrosponding well depth.

The other key point here is "high β". This is β=1.

Re: EMC2 has published a polywell preprint on arXiv

Posted: Fri Jun 06, 2014 12:23 pm
by ladajo
EMC2 built a smaller unit after WB8 to test and develop the startup cycle. That is what this paper is about.


In summary, the present experimental results demonstrate for the first time that high β plasma operation can dramatically improve high energy electron confinement in the magnetic cusp system. This result validates the central premise of the Polywell fusion concept which uses high energy beam injected electrons to create an electrostatic potential well for ion acceleration and confinement. The current plan is to extend the present work with increased electron beam power to sustain the high β plasma state and to form an electrostatic well. If the deep potential well can be formed and the scaling of the electron beam confinement is found to be favourable, as conjectured by Grad and others, it may be possible to construct a compact, low cost, high β fusion power reactor based on the Polywell concept.


This is Wiffleball boys & girls.

Next is to go back to WB8 and check for electron injection efficiency (Ie. document loss rates and loss rate scaling) and corrosponding well depth.

The other key point here is "high β". This is β=1.

Re: EMC2 has published a polywell preprint on arXiv

Posted: Fri Jun 06, 2014 2:19 pm
by MSimon
Just saw the paper when looking for something on J.Y. Park. I'm going to let Tom know it is out. He had been hinting at this a few weeks ago in a conversation we were having about some boards I'm doing for him.

I'll also alert him to this thread.