Talk-Polywell.org

One last note is that a machine cycle is only around 1,020 nS every 300th of a second.

In theory.

MSimon wrote:

One last note is that a machine cycle is only around 1,020 nS every 300th of a second.

In theory.

1uS is an ideal number according to current theory. The 10 to 20nS is a guesstimate based on current understanding of current theory. I agree that's a lot of ifs. That's why there's no PEs in this field yet.

The 300 hz trigger frequency is under software control. It can range from DC to the expected cooling limits (for now) of 1khz, which would roughly equate to 5MW to 17MW output levels.

This immediate control of output, coupled with the price point, could cut through the world's spinning reserves (gas-fired peak load generators) like a hot knife through butter.

Aeronaut wrote:

MSimon wrote:

One last note is that a machine cycle is only around 1,020 nS every 300th of a second.

In theory.

1uS is an ideal number according to current theory. The 10 to 20nS is a guesstimate based on current understanding of current theory. I agree that's a lot of ifs. That's why there's no PEs in this field yet. :wink:

The 300 hz trigger frequency is under software control. It can range from DC to the expected cooling limits (for now) of 1khz, which would roughly equate to 5MW to 17MW output levels.

This immediate control of output, coupled with the price point, could cut through the world's spinning reserves (gas-fired peak load generators) like a hot knife through butter.

Until a device is operational it is all theory. i.e. has a net power DPF ever operated at 300 Hz? Or for that matter is a net power DPF in existence?

The entire aneutronic fusion field is about hope with some theoretical and experimental underpinnings to base it on.

The 300 hz trigger frequency is under software control. It can range from DC to the expected cooling limits (for now) of 1khz, which would roughly equate to 5MW to 17MW output levels.

Over what surface area?

I'm skeptical that pulse rate can be maintained over a useful time period.

TallDave wrote:

The 300 hz trigger frequency is under software control. It can range from DC to the expected cooling limits (for now) of 1khz, which would roughly equate to 5MW to 17MW output levels.

Over what surface area?

I'm skeptical that pulse rate can be maintained over a useful time period.

My main concern is the cap bank's life expectancy at even 100hz.

Anode area is roughly 72 square inches, based on FF-1. The low duty cycle helps with cooling, as does the Be anode circulating a pressurized He coolant. But the power of the X-ray burst is not to be treated trivially.

Assuming that the High Magnetic Field effect has no real point of diminishing returns, I'd personally design to max the field strength (a direct function of cap voltage & thus input current) to aggressively minimize the X-ray generation, which would in turn ease cooling restrictions and power output expectations of the X-ray converter.

Proper DPF design is a series of ratios built around a critical speed of the plasma sheath during the axial phase. This means there's no hard and fast set of dimensions or system timings for any particular application.

Even worse, the cooling specs will be spread between at least the anode, ion converter, and the X-ray converter as it develops, and there's wayyyy too many specs that can and will be misused to pitch "less than optimal" products.

But I'm sure PW will invite it's share of charlatans.

Brian H wrote:

D Tibbets wrote: ...

...
The onl;y pratical way to collect the x-ray energy is to let it head the container and them produce electrical power through a conventional steam plant. If the Q (excess fusion energy out) is not high (eg: greater than 10, you will need to recover as much of the input energy (like bremsstrulung X-rays) and fusion energy that you can.
...

Dan Tibbets

Dan Tibbets

Not so. The X-ray harvesting is also non-thermal; the patent describes a photoelectric method: layered foils each knocking down the energy levels of the X-rays and draining electrons/current, sufficiently thick and efficient to absorb all X-radiation in the "shell" of the device.

Regarding thermal power production in a direct power conversion system.

In a direct radiation to electric power scheme, radiation in effect charges a big capacitor by producing knock-on electrons that are stored in layers of foil. I don’t understand the load leveling mechanism involved with this.

If power continues to be feed into this capacitive storage, and the output is less then the input, doesn’t the system eventually self distrust thermally because of a power imbalance between the systems input over output. Please explain.

Axil wrote:
In a direct radiation to electric power scheme, radiation in effect charges a big capacitor by producing knock-on electrons that are stored in layers of foil. I don’t understand the load leveling mechanism involved with this.

If power continues to be feed into this capacitive storage, and the output is less then the input, doesn’t the system eventually self distrust thermally because of a power imbalance between the systems input over output. Please explain.

A shot in the dark. If the duty cycle is ~ 1000 nanoseconds (1 microsecond), and x-rays are emitted for most of this time, The other 2999 microseconds till the next firing time are idle (no x-ray input). So long as the 'capacitor' drains this charge in this time, it will be ready for the next pulse. Or in effect the drain can be 3000 times slower than the input charge time, and not accumulate excess charge. Depending on efficiency there will be some waste heat though. If the process is 90% efficient, and the X-ray power is ~ 2 MW, then the waste heat would be ~ 200KW. Some modest (?) cooling would be needed.

D Tibbets wrote: ...

A shot in the dark. If the duty cycle is ~ 1000 nanoseconds (1 microsecond), and x-rays are emitted for most of this time, The other 2999 microseconds till the next firing time are idle (no x-ray input). So long as the 'capacitor' drains this charge in this time, it will be ready for the next pulse. Or in effect the drain can be 3000 times slower than the input charge time, and not accumulate excess charge. Depending on efficiency there will be some waste heat though. If the process is 90% efficient, and the X-ray power is ~ 2 MW, then the waste heat would be ~ 200KW. Some modest (?) cooling would be needed.

I think that's about right. Further, there should be no more net power fed into the system once it begins cycling; that's the whole idea of self-sustaining generation. There will be heat, but it is expected to be low-grade, probably not worth the expense of harvesting.

Brian H wrote:

D Tibbets wrote: ...

A shot in the dark. If the duty cycle is ~ 1000 nanoseconds (1 microsecond), and x-rays are emitted for most of this time, The other 2999 microseconds till the next firing time are idle (no x-ray input). So long as the 'capacitor' drains this charge in this time, it will be ready for the next pulse. Or in effect the drain can be 3000 times slower than the input charge time, and not accumulate excess charge. Depending on efficiency there will be some waste heat though. If the process is 90% efficient, and the X-ray power is ~ 2 MW, then the waste heat would be ~ 200KW. Some modest (?) cooling would be needed.

I think that's about right. Further, there should be no more net power fed into the system once it begins cycling; that's the whole idea of self-sustaining generation. There will be heat, but it is expected to be low-grade, probably not worth the expense of harvesting.

Suppose this electrostatic structure gets disconnected from the Grid (No load condition), once the capacitor is completely loaded what happens to all the radiation energy (N megawatts) that enters this electrostatic system. Doesn’t this energy from radiation input convert somehow to heat? It has no where else to go. In the loss of Grid connection case, what keeps this electrostatic system from blowing itself apart?

I doubt the x-ray collection 'capacitor' would normally dump directly into the grid. It would need to be modified into sine waves and at a frequency of ~ 60 HTZ, instead of the probably steep sawtooth wave and 300 HTZ. It would also need to be combined with the output from the particle beams. Some power would be recycled and the rest would go to the grid. There is significant power handling equipment outside the reactor. If connection to the grid is lost (or power demand drops), either a switch could divert the power to ground, or more likely, with sensors, the reactor could be shut down, and taken off line, probably before the next cycle started.
The DPF reactor does not make much power (a few Mega Watts), so a power plant would be made up of a bunch of reactors clustered together (or distributed on a smart grid). If the machine is primed with gas and has a backup power supply like a flywheel or battery array, etc, start up to full power (or shutdown) would probably take no more than a few cycles, which would be well under a tenth of a second. I suspect the system could be very responsive to demands. No steam to warm up or cool down(reactor cooling is a separate issue), no generator to spin up or down. This is one of the advantages of direct conversion.

PS: The DPF fits well with P-B11 fuel because all of the particle energy is in charged particle beams (no neutrons). Direct conversion of this energy and the X-ray bremsstrulung energy allows conversion efficiencies high enough to make a profit. Also, it limits heating loads in this very small machine. I suspect the DPF would have a harder time operating with the otherwise easier D-D fusion. The thermal loads on the electrodes and wall from the neutrons would probably be harder to handle. Though, there would be less x-rays to deal with, the energy in the neutrons could only be converted to useful electricity through a less efficient steam plant. I don't know how things would work out.

Dan Tibbets

Again, DT, that all sounds about right. The constraint on the cycle speed and hence output is in fact cooling of the electrodes. Given engineering advances adequate to the job, it could maybe ramp up to 25MW, e.g. Power smoothing and rectification etc. is as you say mostly a matter of switch control. Which is turning out to be non-trivial. A market for new larger-than-currently-available diamond switches looms!

The switch control required is similar to that developed 10 years ago for PSII (plasma source ion immersion), which is essentially a pulsed-bias 3-D ion implantation technique.

kurt9 wrote:The switch control required is similar to that developed 10 years ago for PSII (plasma source ion immersion), which is essentially a pulsed-bias 3-D ion implantation technique.

I think the problem to date is the power levels they have to handle. Plus the ~10ns response time required. Pick one! Though custom built switches appear to be getting within tolerable range.

Any news on the plasmoids front?

They said they were on course for 3 joules fusion out this month ... hit a stumbling block?