Talk-Polywell.org

I will be surprised, but not sad, if there is one posted.

Still nothing...(yet?)...

http://www.recovery.gov/Transparency/Re ... e=Contract

Look again tomorrow. I hope.

Q4 2011 report is up.

During 4Q of 2011, EMC2 has modified the electron injectors to increase the plasma heating. The higher plasma density in WB-8 prompted the need for higher heating power. We plan to operate WB-8 in high beta regime with the modified electron injectors during 1Q of 2012.

Seems like if the machine operated as expected, this would have been anticipated. Not sure what it means, though -- higher losses? Something else?

CellJeffe wrote:Q4 2011 report is up.

EMC2:

During 4Q of 2011, EMC2 has modified the electron injectors to increase the plasma heating. The higher plasma density in WB-8 prompted the need for higher heating power. We plan to operate WB-8 in high beta regime with the modified electron injectors during 1Q of 2012.

I have no idea what the implications of this statement might be.

I guess high plasma density is a good thing... I guess...

Isn't this a tokamak trick?: "...modified the electron injectors to increase the plasma heating."

And wouldn't "The higher plasma density" imply that the Whiffle ball was not as large as expected, thus "...prompted the need for higher heating power."?

And isn't this a good thing?: "We plan to operate WB-8 in high beta regime..."

Just asking

Higher plasma density seems to be good news to me. The Wiffleball effect is what drives the obtainable density, and this is the backbone of the Polywell as a viable power producer.

That they need more electron current and/ or voltage suggests that they are struggling with the power supplies for the electron injection (magrid potential). EMC2 had considerable difficulty obtaining the power for WB 6 and other machines, thus the use of capacitor banks.

The problem may be :
1) Adequate electron power, but for less than desired time periods (pushing towards longer steady state operation.)

2) Miscalculation of needs.

3) Greater electron losses than hoped for (bad).

4) Higher Wiffleball trapping factors- thus greater densities obtainable, but to reach these limits more electron power is required- this would be mostly good, I think, as it would imply that the potential for the machine is greater than anticipated

5) Higher peak currents needed to drive the larger machine to high beta, which may have some significance for start up or pulsed operation, but not on steady state.

6) Changing input electron voltage from eg- 12,000 volts to 30-80,000 volts. Important for testing under conditions where a successful D-D power plant would operate.

7) All of the above

8 ) None of the above.

9) some of the above.

10) Nothing new. They knew that the electron power was insufficient for high Beta, and previous tests were all at lower Beta conditions, useful for a lot of reasons, but not ideal.

I like the assumption that they are pushing towards higher voltage conditions. It suggests the evolution of the program. Heck, it might even suggest that they are trying to achieve input electron energies that would allow for P-B11 testing. Or on the other side of the coin, the results are disappointing, but they are hopping to finds some tweaks that salvages the machine.

Dan Tibbets

Those seem like a good set of options. The wording suggests that the driving force for these changes is that plasma density is higher. I assume that this was unexpected (why build the machine under-specd?). That doesn't immediately make me suspect electron loss (the less precise reading <<we need more power>> might).

I don't pretend to understand the physics here -- why does higher plasma density require higher heating power? I would have thought that higher electron potentials drive higher plasma density. Is ion containment better than expected, so that more current (electrons) are required? Is this higher density yielding more frequent (useful) collisions, or does this mean that power loss scaling isn't as low as expected? Is this saying anything interesting about the electron-ion balance in the system?

What does "high beta" mean? I thought the optimal beta was "1". I don't typically think of "1" as being "high", but that word is relative (and therefore somewhat meaningless). Was the system previously run at beta << 1? Isn't that not as useful for determining whiffle-ball effect? Or is the machine being run at a higher condition (#6)?

Talk about nuanced....

I agree with Dan's point 6 and 11 (which you failed to number!) most especially.

Bring on the p+B11 burns, baby!

I like to high Beta part, perhaps they want to test high temperature limits for production machine design?

Just had this idea, since they have a microwave engineer, and discuss temperature. Maybe they don't intend to rely on accelerated ion collisions to produce fusion. Since they already have high plasma density relative to a tokamak, just suddenly spike the temperature of the entire confined plasma with microwaves to fusion level, fusion throughout entire plasma, not just r = 0.

This is taking me a bit to adapt to. The first thing I thought when I saw "plasma heating" was "Uh oh, is this Plan B?" Now am I to understand that a Maxwellian plasma (in a Polywell) is not necessarily a bad thing? And does that not make a p+B11 device less likely?

Or am I misunderstanding what is meant by "plasma heating"?

I remember Dr Nebel said the polywell works in higher pressure than expected.
This may be a good thing then it may solve the problem to maintain the "vacuum" then fuel are added.
But maybe it forbid the pB fusion.