The Boys At Talk-Polywell Have Struck Paydirt

The boys at Talk Polywell have uncovered the details of the WB-8 contract [pdf]. Those details can give us some insight into how WB-7 has gone. From the looks of things - rather well.

The current effort will build on what has been completed under these previous contracts as well as requirements to provide the Navy with data for potential applications of AGEE with a delivered item, wiffleball 8 (WB8) and options for a modified wiffleball 8 (WB8.1) and modified ion gun. The objective of this procurement is validation of the basic physics of the AGEE concept as well as requirements to provide the Navy with data for potential applications of AGEE. It builds upon previous concept-demonstration bench top versions of plasma wiffleballs. As such, it comes under the FAR 35.001 definition of applied research. The contract will be for a wiffleball 8 with 2 options for modifications to the wiffleball based upon it’s success.

3.1.1 The Contractor shall construct and test a small-scale MG Insulated, Wiffleball Polyhedral Device, WB8. WB8 shall be built based on results of WB7 (built under contract N68936-03-C-0031) and shall utilize design and performance knowledge gained from test of prior WB machines.

3.1.2 The design shall use circular coils around each main face cusp axis. The device shall use emitter electron gun arrays and an ion beam drive. The machine will be operated in magnetic fields with pulsed currents. WB8 shall be operated at a magnetic field strength of approximately 0.8 Tesla, which represents an increase of 8 times the magnetic field strength of previous WB machines. Improvements over previous WB machines in WB confinement, ion energy and fusion reactivity are expected as a result of these changes to WB machine design.

3.1.3 Within 20 days of completion of testing of the WB8, the contractor shall deliver a report detailing the results of the experimental testing of this MG Insulated, Wiffleball Polyhedral Device, WB8. The report shall provide sufficient information to guide programmatic and design decisions about further, refined design efforts for similar devices. The report shall address the plasma dynamics of WB devices, and shall address the scaling laws that apply to polywell fusion. (A001)

Circular coils means that there will be no significant change in geometry. That is good. Apples to apples comparisons. An increase of field strength by a factor of 8 means - if the scaling laws hold a factor of about 4,000 increase in power out. If WB-7 was similar to WB-6 it means an increase from 3 neutrons a shot to 12,000. A real countable number i.e the error bars will be much lower. A count of 3 can actually be considered a count of 3 +/-2. That is a big error bar. For 12,000 the error bar is on the order of +/-100 about 1%. That makes improvements or degradations of 5% easily detectable. Where as in the first situation (WB-6/7) changes that doubled or halved the output rate would be hard to detect.

3.1.4 Within 30 days of build and test of WB8, the contractor shall provide a predictive model of WB behavior including data points for detailed 2D/3D profile measurements of plasma density, ion energy and WB magnetic field structure during follow-on tests to validate the scientific basis for a Polywell fusion power reactor, and guide further research. The contractor shall coordinate with the Government for a program review meeting at the contractor’s facilities to be held no later than 40 days after the testing of the WB8 and shall provide the detailed predictive model and data points at this program review meeting.

3.1.5 The contractor shall deliver a periodic progress report specifying status information of the experimental testing of the MG Insulated, Wiffleball Polyhedral Device, WB8. (A002)

The magnetic profile of an operating device is critical for knowing how the device actually operates. Without that it is very difficult if not impossible to design in improvements.

3.1.6 The contractor shall deliver a conceptual design for a follow-on fusion demonstration device, WB-9. Conceptual studies will focus on the feasibility of extending the WB-8 results to this device and determining the suitability of this concept as a fusion reactor. This design will be delivered at the end of the contract.

So the program is starting to take on a life of its own. A WB-9 device is already under consideration even before experiments on WB-8 are even completed. This indicates a fair amount of confidence in the forthcoming results. Excellent.

3.2.1 Enhanced Ion Drive with PB11 (proton/boron 11): Based on the results of WB8 testing, and the availability of government funds the contractor shall develop a WB machine (WB8.1) which incorporates the knowledge and improvements gained in WB8. It is expected that higher ion drive capabilities will be added, and that a “PB11” reaction will be demonstrated. The contractor shall investigate and validate the plasma scaling laws with respect to B-field, voltage and reactor size. The contractor shall investigate the feasibility of a neutron-free fusion power reaction using a polywell WB machine. It is anticipated that improvements in WB confinement, ion energy, and fusion reactivity will be demonstrated in WB8.1. Improvements over the WB8 predictive, computational model are expected, which should yield a better understanding of the WB fusion reaction thus allowing optimization of the WB machine.

3.2.2 The contractor shall deliver a report detailing the results of the experimental testing of WB8.1. The report shall provide sufficient information to guide programmatic and design decisions about further, refined design efforts for similar devices. The report shall address the plasma dynamics of WB devices, and shall address the scaling laws that apply to polywell fusion, and the feasibility of the PB11 reaction. The report shall address the conceptual requirements for a polywell fusion reactor capable of generating approximately 100mW. (A0001)

3.2.3 Within 30 days of testing, the contractor shall update the predictive computer model of WB behavior created under paragraph 3.1.4 using the PB11 reaction and shall deliver the model within 30 days of completion of initial tests specified in paragraph 3.2.1.

The fact that they are contemplating work on the pB11 reaction is very encouraging. That fuel is one of the most difficult to burn in a fusion reactor. Which means testing with lesser fuels (or simulated fuels) has gone very well indeed.

At 100 milliwatts for a follow on reactor they are starting to get into the power range. If they can get that kind of power with .3 m dia. coils and .8 T fields, then a reactor with 3 m coils and 10 T fields should produce about 2.5 Mega Watts if the scaling laws hold.

3.3.1 The contractor shall develop an enhanced ion drive system that is compatible with Wiffleball 8.1 and projected future wiffleballs. The ion drive system shall be capable of injecting protons (ionized Hydrogen), and ionized Boron 11. The ion drive system shall be capable of generating ions in sufficient quantity to fully fuel the wiffleball fusion machines.

If they are going to fuel even a small machine the ion guns are going to have to be capable of multi amp currents - each.

Well that is my first cut at digesting the news. If you want to figure out more a look at all the links at Talk Polywell will be helpful. I especially liked this inventory [pdf] of items purchased since about 1999.

What it means about past work: it went well. What it means for the future: verifying engineering rules More: there is a plan to test the Hydrogen/Boron 11 fuel combination More: They must be confident of results since they are planning a WB-9

You can learn the basics of fusion energy by reading Principles of Fusion Energy: An Introduction to Fusion Energy for Students of Science and Engineering

Polywell is a little more complicated. You can learn more about Polywell and its potential at: Bussard's IEC Fusion Technology (Polywell Fusion) Explained

It’s the specification for a test-model nuclear fusion reactor called a Polywell reactor. If all goes well, the next model will produce more power than it consumes. If built at a commercial scale, such a reactor would not only be a revolutionary source of waste-free grid electrical power, but would be a perfect power source for submarines, aircraft, and spacecraft.

Fun Fact: the basic technology behind this design was originally developed by Philo T. Farnsworth — yes, the same guy that invented electronic television.

This isn’t just news of the first order, it makes everything else pale to insignificance. If they pull this off, the game changes completely, and it looks like they are about to pull it off. I would put it in breaking if I were the mod.

I saw the wiki poage was updfated a few weeks ago after a very long period of practically no news. Great times. Philo would be proud; the Tokamak folks still don’t have a usable neutron source and he built one 50 years ago.

I still have not grasped how the power is to be reliably harnessed though. Still way off IMO, but visible as opposed to the tokamak boondoggle.

"I still have not grasped how the power is to be reliably harnessed though."

If the polywell runs one of the neutronic fusion cycles (D-T, D-D), it will extract energy just like the ITER (i.e neutrons lose energy in a moderator---like water--heat up the water, make steam, and drive a generator). This is limited by the Carnot cycle, but no worse than a fission reactor or other fossil fueled power plant. The large number of neutrons tends to "make things radioactive", so there will be some radwaste associated with the process.

If they succeed in running one of the higher energy aneutronic fusion cycles (PB11), then they can design the electrostatic confining fields to "leak" ions at a specific point and do magnetohydrodynamic conversion by "slowing down" the high energy particles, which can be up to 80% efficient. Thanks, I wondered how you eventually turned it into shaft work, I didn't realize they could funnel the neutrons. Then you have a standard moderator-to-heat solution. You are saying the neutrons can be funneled, right? Or am I missing something? I looked up MHD from your post, and now I think I understand the debate over whether it is Maxwellian and for how long. Thanks for that! Incidentally I did read some speculation on trapping alpha in the chamber and using it as an additional source of current, like a giant pacemaker battery I guess. Just speculation I know.

Here is a link to a neutron trap.
http://www.aip.org/png/html/neutrap.html

magnetic trap for neutrons
http://www.nature.com/nature/journal/v403/n6765/full/403062a0.html

So-called cold neutrons are used for cancer treatment. Cool use of N physics.

I saw that when I started investigating the fusor. But unlike a fusor, I wasn’t sure how you get the neutrons out of the polywell. I guess you want to “leak” them through a cusp? Or are they directional at all?

The proton/Boron 11 reaction (PB11) produces almost no neutrons. Instead alpha particles are generated. These are charged particles and so can be steered out of the reactor and can directly generate a very high voltage dc current. So you don’t need a steam plant(20 to 30% efficiency and expensive), just a tall stack of high voltage semiconductor switches and some transformers (85 to 95% efficiency and MUCH cheaper) to make 60Hz electrical power for the grid.

Assuming no show stoppers of course.

"Thanks, I wondered how you eventually turned it into shaft work, I didn't realize they could funnel the neutrons. Then you have a standard moderator-to-heat solution. You are saying the neutrons can be funneled, right? Or am I missing something?"

Not really. They need to use the "moderator" approach with neutrons because they CAN'T "be funneled". They have to be "slowed down" and lose energy by collisions with a light nucleus (like the protons in water).

But with the PB11 reaction, the products are two high energy alpha particles, which can most definitely be funneled and slowed either by electric or magnetic fields.

LOL

Gravity?

I failed fisiks... I can ‘do’ electronics, tnat follows some pretty well established rules. Fisiks OTOH is full of strange things, colors and charms - almost magic, eh?

"And I thought it was a spoof on playing whiffle ball...."

Actually, it is. They call the reactor a "wiffle ball" because a 3D map of it's magnetic fields looks like (you guessed it), a wiffle ball. Who says genius physicists don't have a sense of humor???

Most people I know that are successful, happy, and generally conservative...have a great sense of humor!!

So it figures......

Thanks!

Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.