sam

5 ms·

1.
by sam 5mo ago
Well said about the “lossy crankshaft”. As for what determines Q, that’s up next, stay tuned :)
2.
by sam 5mo ago
Power to magnets (at least those not contributing to heating) are assumed to be included in the house load.
3.
by sam 5mo ago
Thanks - what browser?
4.
by sam 5mo ago
Yeah, it’s slightly buried - the publication with all the details, including the math is linked to in footnote 3 of the explainer article, https://pubs.aip.org/aip/pop/article/29/6/062103/284782
5.
Fusion Power Plant Simulator(fusionenergybase.com)
193 points by sam 5mo ago|129 comments
6.
by sam 8mo ago
This is mistaken. In space a radiator can radiate to cold (2.7K) deep space. A thermos on earth cannot. The temperature difference between the inner and outer walls of the thermos is much lower and it’s the temperature difference which dete
7.
by sam 1y ago
In the context implied above it is the ratio of fusion energy released to laser energy on target or the laser energy crossing the vacuum vessel boundary (they are the same in this case). So it would have been more precise to say "targe
8.
by sam 1y ago
We are careful to always specify what kind of “breakeven” or “gain” is being referred to on all graphs and statements about the performance of specific experiments in this paper. Energy gain (in the general sense) is the ratio of fusion ene
9.
by sam 1y ago
It’s the ratio of fusion energy released to heating energy crossing the vacuum vessel boundary.
10.
by sam 1y ago
Companies like Commonwealth Fusion Systems are an example of those utilizing high-temperature superconductors which did not exist commercially when ITER was being designed.
11.
by sam 1y ago
Author here - some other posters have touched on the reasons. Much of the focus on high performing tokamaks shifted to ITER in recent decades, though this is now changing as fusion companies are utilizing new enabling technologies like high
12.
Progress toward fusion energy gain as measured against the Lawson criteria(fusionenergybase.com)
232 points by sam 1y ago|142 comments
13.
by sam 3y ago
This comment thread will go down in history along with the famous HN Dropbox thread. This thing is incredible and will eventually crush the iPhone. Solves iPhone addiction while retaining the utility of an iPhone? Solid gold.
14.
Significance of the Achievement of Scientific Energy Gain at the NIF(arpa-e.energy.gov)
1 points by sam 4y ago|0 comments
15.
by sam 4y ago
We only included projected values of SPARC and ITER because they're the only ones whose physics basis has been published in the peer-reviewed literature. We would certainly like to include other devices - hopefully this will encourage
16.
by sam 4y ago
Thanks. We published a number of prepublication versions over the past year on arXiv to gather feedback from the physics community before submitting to Physics of Plasmas last December. The version linked to above (and in the tweet) is the
17.
by sam 4y ago
Author here. The black curve represents the hot-spot ignition condition for a laser inertial confinement fusion (ICF) experiment (like the NIF). This means that during the short period of inertial confinement, the self-heating exceeds all l
18.
by sam 5y ago
Surprising to see so much negativity here. Limiting to a small number of headlines is a useful mechanic. I can see this going in a number of interesting directions.
19.
by sam 5y ago
If you're interested in wheels, check out The Bicycle Wheel by Jobst Brandt. If you're building wheels it's a must have.
20.
Cruisin' for Nonconventional Fusion with ARPA-E(arpa-e.energy.gov)
1 points by sam 5y ago|0 comments
21.
by sam 6y ago
I’m guessing you’re referring to HL-2M which indeed in testing. But that tokamak is not designed to generate electricity but rather to study long pulse durations (~5s) at reactor relevant temperatures.
22.
by sam 6y ago
Author of that article and plot here. SPARC is projected to have energy gain Q >=2 and potentially up to 11[1]. ITER is projected to achieve Q of >=10[2] so I would guess that SPARC's expected triple product would be in the same
23.
by sam 6y ago
Most of the ports are used for diagnostic equipment, things like laser interferometers to measure plasma density or other devices to measure plasma temperatures. Also some ports are used to inject neutral beams for heating.
24.
by sam 6y ago
I’m working on this exact issue. You can view all fusion energy companies here and filter by location. https://www.fusionenergybase.com/organizations/ You can view each of their funding histories on the company detail
25.
by sam 6y ago
Yes, check out https://www.fusionenergybase.com/ which I've put together. List of organizations are here, https://www.fusionenergybase.com/organizations and individual projects are here, https:/&
26.
by sam 6y ago
ITER and Commonwealth can (and in my opinion should) be seen as complimentary endeavors. ITER has been designed with relatively conservative magnet technology and will very likely provide the physics results that need to be understood in or
27.
by sam 6y ago
That’s right, there are other fusion fuels that have only charged fusion products which could be directly converted to electricity. This is in contrast to deuterium - tritium which releases 80% of its energy in a neutron which has zero char
28.
by sam 6y ago
The typical design for a fusion power plant that runs on deuterium tritium fuel is to place a lithium "blanket" around the plasma. 80% of the energy released in the deutrium - tritium fusion reaction comes out in the energy of a n
29.
by sam 6y ago
There are a few reasons why the investment is flowing. 1) New enabling technologies, including high temperature superconducting tape, algorithms for plasma control and diagnostics which take advantage of new hardware (GPUs), and advanced m
30.
by sam 6y ago
Mach's principle. Why is there a "preferred" rotational frame of reference in the universe? Or as stated in this Wikipedia article, "You are standing in a field looking at the stars. Your arms are resting freely at your

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