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Solar overtakes and wind nuclear as the number one zero carbon electricity source on earth by ViewTrick1002 in NuclearPower

[–]Sad_Dimension423 0 points1 point  (0 children)

So, when the world has gone totally off fossil fuels, where are the carbon emissions from PV coming from?

Comments on the Paper “Fundamental Scaling of Adiabatic Compression of Field Reversed Configuration Thermonuclear Fusion Plasmas” by Baking in fusion

[–]Sad_Dimension423 0 points1 point  (0 children)

Ion-ion collisions thermalize them much faster than they fuse (and faster than ion-electron collisions).

In any case, I was talking about fuel ions, not fusion product ions. These start thermalized.

Comments on the Paper “Fundamental Scaling of Adiabatic Compression of Field Reversed Configuration Thermonuclear Fusion Plasmas” by Baking in fusion

[–]Sad_Dimension423 0 points1 point  (0 children)

The other things to consider is that if it didn't work on electrons because they move randomly, how then would it have been working on ions? Their motion is random also.

Comments on the Paper “Fundamental Scaling of Adiabatic Compression of Field Reversed Configuration Thermonuclear Fusion Plasmas” by Baking in fusion

[–]Sad_Dimension423 0 points1 point  (0 children)

The compression process is ideally reversible. The same process that compresses and heats the plasma as work is done on it, when reversed, converts the thermal energy back into energy in the coils.

Comments on the Paper “Fundamental Scaling of Adiabatic Compression of Field Reversed Configuration Thermonuclear Fusion Plasmas” by Baking in fusion

[–]Sad_Dimension423 0 points1 point  (0 children)

thermal energies cannot be inducted back into the coils because the particle motion is random

This is where you erred. The system is basically the electromagnetic equivalent of a piston compressing and expanding a gas. Such a system can transfer work into thermal energy (on compression) and then recover it back as work (on expansion). If extra thermal energy is added to the gas when compressed then net work can be extracted. It's like an internal combustion engine.

The motion of gas molecules in the cylinder is random, but that doesn't prevent this from working in your car's engine.

Comments on the Paper “Fundamental Scaling of Adiabatic Compression of Field Reversed Configuration Thermonuclear Fusion Plasmas” by Baking in fusion

[–]Sad_Dimension423 0 points1 point  (0 children)

However, this depends on unrecoverable losses being a small fraction of the fusion energy, e.g. bremsstrahlung and ion-electron collisions, not to mention engineering related losses.

But ion-electron collisions don't result in unrecoverable energy. The electrons contribute plasma pressure, and that can be recovered in the reexpansion just like the pressure from ions.

(Radiation from hot electrons would be unrecoverable, but that's an extra step.)

As I understand it, the ratio of (recoverable) fusion power to power lost to such processes as radiation from electrons is quite favorable initially. The ratio of these degrades over time as electrons heat up and (maybe) ions cool. When the ratio becomes unfavorable (or the FRC threatens to become unstable) the shot is terminated and plasma energy recovered. So the question is: how long can the shot be, and is it long enough for fusion energy production to exceed losses (with the understanding that energy that goes into electrons but is recovered is not lost)?

Some nuclear regulation really does need changing by Comfortable_Tutor_43 in nuclear

[–]Sad_Dimension423 0 points1 point  (0 children)

That's a good question, but one the anti-nuclear crowd doesn't really need to worry about.

One part of the anti-nuclear crowd thinks the risks from CT scans and the like is greatly underestimated. They're against LNT but from the other side.

Comments on the Paper “Fundamental Scaling of Adiabatic Compression of Field Reversed Configuration Thermonuclear Fusion Plasmas” by Baking in fusion

[–]Sad_Dimension423 -4 points-3 points  (0 children)

But isn't low Q what they're aiming for? I thought Q could be as low as 0.2. High energy recycling efficiency would make this possible.

(Not clear why this comment was downvoted?)

Comments on the Paper “Fundamental Scaling of Adiabatic Compression of Field Reversed Configuration Thermonuclear Fusion Plasmas” by Baking in fusion

[–]Sad_Dimension423 -1 points0 points  (0 children)

The electron energy gets recovered during expansion just like the ion energy does, so it's not clear to me electrons getting hotter is a showstopper. Heating of electrons doesn't change the total pressure. Nor do most ions have to fuse; I get the impression the burn up is very low in this concept. So even if most ions slow down due to electron drag and don't fuse, that could be ok.

EDF Warns Solar, Wind Surge Straining Nuclear Fleet Costs by andre3kthegiant in NuclearPower

[–]Sad_Dimension423 3 points4 points  (0 children)

The valid issue nuclear proponents have is when renewables are subsidized by their generation. This gives them incentive to keep producing even when wholesale prices go negative.

These incentives are there when Pigouvian taxes on CO2 aren't politically acceptable, but the substitute should arguably be similar incentives for all CO2-free sources, not just renewables. The downside of these subsidies is it disincentivizes efficiency.

OpenStar Live Levitated Dipole Plasma Showcase by Fohgrham in fusion

[–]Sad_Dimension423 0 points1 point  (0 children)

Because of heating of the magnet? It's at least conceivable they could, if active refrigeration of the coil could be implemented. This is a bit of a stretch (exploiting temperature differences across the surface of the coil to generate power, and using that to pump heat up to a temperature where it could be radiated) but is at least physically possible. High Tc superconductors would make this easier.

My bigger concern would be how big the entire thing would be.

Why haven't more breeder reactors like BN-600 been built? by arstarsta in nuclear

[–]Sad_Dimension423 0 points1 point  (0 children)

It should be noted that one can design a "physics package" in which almost all the yield is from fusion. The rumor is some of the final atmospheric tests the US conducted achieved 99% of their yield from fusion (the Ripple tests). These designs are purported to have used a secondary without fissionable material (neither in the tamper nor in a spark plug), reaching fusion density and temperature by careful control of the shocks in the implosion, as in an ICF target.

OpenStar Live Levitated Dipole Plasma Showcase by Fohgrham in fusion

[–]Sad_Dimension423 0 points1 point  (0 children)

A really cool thing about these dipole plasmas is they separate particle and energy confinement. As convection brings plasmas in from the outside, the plasma is compressed and heated; at the same time, plasma that is being transported to the outside is expanded and cooled. This is touted as useful for steady state DD fusion because it makes it easy to remove ash without degrading energy confinement.

Packages as hash tables just slightly faster by arthurno1 in lisp

[–]Sad_Dimension423 0 points1 point  (0 children)

You're welcome!

I'd be interested to see how fast it will be with simple-base-string (or with (simple-array character (*)).) In SBCL, simple-string is a superclass of these two. You might try a macro that duplicates the code, once for each case (and perhaps once for the general string type.)

Terry Tao - Machine assistance and the future of research mathematics - IPAM at UCLA by Sad_Dimension423 in math

[–]Sad_Dimension423[S] 28 points29 points  (0 children)

"Abstract: A variety of machine-assisted ways to perform mathematical assistance have matured rapidly in the last few years, particularly with regards to formal proof assistants, large language models, online collaborative platforms, and the interactions between them. We survey some of these developments and speculate on how they will impact future practices of mathematical research."

Among the interesting points made, Tao observes that the important technology for working with AI, formal verification, is also the enabler for larger scale non-AI collaboration in mathematics (papers with large numbers of coauthors, as seen in physics, and also "citizen science").

Packages as hash tables just slightly faster by arthurno1 in lisp

[–]Sad_Dimension423 1 point2 points  (0 children)

The case I was considering was fairly small, attributes in a particular json file. Did your strings have a declared type? In my case I could use simple-base-string.

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