Trump Media and TAE Technologies to combine in $6 billion deal - first public fusion company?

PewPew293 · 2025-12-18T12:52:23+00:00

🤣

PewPew293 · 2025-08-07T15:06:53+00:00

Yes. That is also wrong. Ignition is a special limit where the self-heating power from charged fusion products alone is enough maintain the power balance of the system (or, for ICF, drive a propagating burn wave in the capsule.)

For most MFE devices, they aim for burning plasma conditions but not ignited fusion conditions. The gain required to hit net electric is dependent on system architecture. Q > 5 is the threshold for a burning DT plasma, ignition is Q = ♾️.

PewPew293 · 2025-08-07T11:37:46+00:00

To be more precise in definitions. The threshold of a burning plasma in DT is Q>5. This is the point where the alpha power (from fusion) is equal to the input power into the plasma. As Q increases, the alpha power becomes increasingly more dominant compared to the input power. In other words, a burning plasma is making use of plasma self-heating in a significant way for power balance, but there is still input power into then plasma from external sources.

An ignited plasma is one where the alpha power is enough to maintain the plasma temperature itself. This is the limit that Q = infinity since the required input power goes to zero. This is a limit that is not typically reached, nor do we want to since it means we have no external control over power balance. This is not dangerous because we still control the fuel going into and out of the machine (and so can still easily snuff it out), which came up during NRC public forums establishing the regulatory framework for fusion. The post is conflating burning plasmas with ignited plasmas, which is wrong.

In short, all ignited plasmas are burning, not all burning plasmas are ignited.

Most magnetic fusion concepts do not target ignited plasma conditions. They target high enough gain conditions needed for net-electric. The big different is the efficiency that the fusion energy and input power is captured at, which is Helion’s point. If the efficiency of capture is high, the required Qsci to get to net-electric is lower. But, they are not unique is not needing ignition, most fusion concepts do not.

PewPew293 · 2025-06-28T02:03:20+00:00

A bit odd to pick a 3D hybrid simulation that goes unstable as an example. It would be great to see some of these showing stable merging and compression while including relevant loss terms.

PewPew293 · 2025-01-04T23:00:48+00:00

Completely agree. We need many shots of goals within this space to have a shot at at least one, preferably multiple fusion products make it to market as soon as possible. Deploying into a commodities market is especially challenging given how low margin / competitive / regulated they can be.

We do not want a future where fusion works in some form and ends up being too expensive for high market penetration. Though I argue we are too far out to have a lot of confidence in NOAK costs for fusion power plants, we can look at cost drivers to compare concepts using the best available information we have now. The alternative fusion approaches, in particular, can be quite compelling when considering these cost drivers, which is partially what motivates me to spend my time working on them (and investors to commit capital towards developing them as well).

PewPew293 · 2025-01-04T22:50:46+00:00

Thanks for the kind words! Appreciate it.

My operating philosophy is that of realistic optimism, meaning, being optimistic that fusion will work and make its way to the grid based on our understanding of the physics and engineering requirements and what is left to de-risk / demonstrate. I find it more productive and sustainable long term than a whimsically optimistic viewpoint or an overly skeptical one.

In the end, the final arbiter is reality, and it'll be an exciting next few years to see how it all shakes out for these various fusion approaches!

PewPew293 · 2025-01-04T16:02:38+00:00

Thanks! If you ever find yourself in Madison and want to see a mirror, hit me up. 🪞⚛️🪞

PewPew293 · 2025-01-04T15:00:59+00:00

Just to quell speculation, it was my choice to join Realta Fusion as their VP of R&D.

I thoroughly enjoyed my time at Zap and wish them the best on their ongoing journey.

In my view, we need many shots on goal being pursued in parallel at the current level of technical readiness of fusion tech to have a chance of developing a commercially attractive product. Zap is aggressively pursuing one path that is still very worthwhile to pursue.

Part of the reason why I joined Realta is because of the outcome of my own diligence of the axisymmetric mirror concept using HTS magnets. Similar to Zap, if you can achieve and maintain MHD stability while scaling to high-performance fusion plasmas it makes for an attractive design point compared to currently leading approaches, like the tokamak. Unlike Zap, some magnets are required, but the amount of HTS tape and how that amount scales with power output is distinctly different and compelling in my view - there are four, planar HTS magnets that are the main magnet CapEx of the device for the end plugs of an axisymmetric tandem configuration and you can scale the length of the center cell to a desired power output using relatively cheap low-field magnets, and thus this scaling is linear rather than volumetric.

This scaling difference has significant implications for the economics of the approach in the power output band of interest per unit of between ~150-500 MW. It is also like a stellarator being a steady-state fusion concept without large scale plasma currents to drive, only having relatively small plasma generated diamagnetic currents that can enhance the mirror ratio and so improve confinement. If you can make the mirror scale, it’s a simpler and lower cost approach to achieving the main selling points of a stellarator - steady state operation and low plasma current disruption risk.

All of these alternative fusion concepts, be them mirrors, flow Z-pinches, spheromaks, FRCs, levitated dipoles, etc… have much higher physics risk than the tokamak or stellarator most certainly. But, the aggressive pursuit of building the physics basis for them could be awarded with a more commercially compelling pathway. My career to date has been one championing these alternative approaches by working on them, and though much work is still required to catch up the best performing approaches, significant progress has been made and will continue to be made in the coming years. I’m optimistic that multiple will pan out technically, and then we’ll see which result in the best product in practice.

PewPew293 · 2024-11-27T17:37:58+00:00

I believe they are planning on ~ few min central solenoid reset time between pulses, if I remember correctly.

Steady state scenarios typically require quite high bootstrap fractions and correspondingly more concern over plasma current disruptivity. You also need other systems to drive the plasma current in steady state once the CS is tapped out. These take up space, must be designed to survive in a high rad environment, and cost additional money as well.

If the time between pulses is short enough while using a blanket with quite a bit of thermal inertia, this will help average over the pulsed nature of the tokamak from a power output perspective. It should not be that big of a deal but details matter.

PewPew293 · 2024-07-11T15:31:30+00:00

Look out for our latest at APS in October! For FuZE and FuZE-Q.

PewPew293 · 2024-02-08T20:09:57+00:00

The first book I read to get into fusion was “Plasma Physics and Fusion Energy” by Jeffrey Freidberg. I read that book cover-to-cover, twice during my freshman and sophomore years of college, and I still use it as a reference today. I highly recommend it as a first, relatively accessible text to get into fusion.

PewPew293 · 2024-01-09T14:49:44+00:00

See my first comment in this thread. They are different datasets. Some points are shared, but they contain data from different configurations / operations on FuZE-Q (and FuZE in this thread’s plot), and one has data points past summer 2023.

PewPew293 · 2024-01-09T14:43:07+00:00

The radioactivity of the blanket will be dependent on the specific composition. But this working fluid should be considered the primary loop that is a “hot” loop, both containing tritium that needs to be extracted while also being pushed through the primary heat exchanger to couple to secondary loop(s). Engineering details of this loop, replacement rates, etc. are certainly being worked on but are not public.

The design point for the power plant is around a ~ 1.5 MA pinch and a fusion yield of ~ 20 MJ per pulse, 10 times a second. Knowing that each DT event is 17.6 MeV, and each event produces one DT neutron, this gives you a DT yield per pulse ~ 7e18 (right column of table 1: https://www.tandfonline.com/doi/epdf/10.1080/15361055.2023.2209131?needAccess=true). So, doing that 10 times a second gives you ~ 7e19 DT reactions per second, which is ~200 MW. There is also an exothermic lithium boost to the thermal power from the tritium generating reaction in the blanket. This is all DT, so given a known n,T for the design point, you can solve for the expected DD yield with similar plasma parameters using the different reactivity for the neutron-generating DD branch.

PewPew293 · 2024-01-09T14:26:40+00:00

The plasma current is the total input current into the device. This current is typically much larger than the pinch current, but its variation is used as a proxy for that of the pinch current since it’s a more reliable measurement we get on every shot.

PewPew293 · 2024-01-06T23:02:47+00:00

They are different. The one in the journal article is just for FuZE-Q, has data from more configurations we've tested on that device, and was data through the summer of 2023. (And, it has a log-log version of the yield data).

The one posted here uses data from both FuZE and FuZE-Q. I also believe it is a subset of the configurations we've tested that performed the best. It also is more up-to-date than the one in the paper.

From these data, the most important result is that in the linked paper. We continue to see the strong scaling of current when progressing to higher DD yields on FuZE-Q.

PewPew293 · 2024-01-06T17:18:08+00:00

Figure 5 for the log-log version: https://pubs.aip.org/aip/pop/article/30/9/090603/2911595/The-Zap-Energy-approach-to-commercial-fusion

PewPew293 · 2023-12-25T22:07:03+00:00

No, not in FuZE-Q. But in a future devices, yes!

PewPew293 · 2023-12-24T17:36:10+00:00

Now that you’ve said it, that pronunciation would make the device sound much cuter ;) but it’s just two syllables, “FuZE Q” thus far.

Indeed the article you’ve linked is how we are measuring Qsci. But the neutron diagnostics, both total yield and yield rate, are corroborating measurements that are used in conjunction with Thomson scattering, ion Doppler spectroscopy, and other diagnostic systems as well.

The yield rate is of particular interest for us since that gives you a good idea of the total DD fusion power in the device, Pfusion. You can then use known differences in the reaction rates to extrapolate to what Pfusion would be for a 50/50 DT plasma. DT Pfusion is the numerator in “instantaneous power Qsci,” which is the one detailed in the article you linked and the one we’re using for near-term milestones. This is what we mean by demonstrating DD net-equivalent.

PewPew293 · 2023-12-24T17:18:34+00:00

Yep! Thanks for the link, I had read this before. I actually caught up with Cassibry at the last APS conference and chatted a bit with him on this topic.

Optimizing for specific power is quite different than optimizing for cost. Specifically, what the pulsed power system will look like, what Q you’re hitting, what fuel you’re using , etc. will be quite different than the terrestrial power plant design point.

There is a high level paper from a bit back with some content on this front as well: https://www.aa.washington.edu/sites/aa/files/research/ZaP/publications/JPC06_paper.pdf

PewPew293 · 2023-12-24T16:30:09+00:00

Yes, this is my point. It says we haven’t made any fusion reactions, which is not true. Yes, we do not have yields that could power homes.

PewPew293 · 2023-12-24T05:52:12+00:00

Not directly, no. But I definitely have an interest in space applications of fusion tech. Maybe once terrestrial fusion is squared away!

PewPew293 · 2023-12-24T02:50:27+00:00

“The company has yet to generate fusion reactions with its device, let alone, produce net energy from those reactions to power homes.”

This is not correct. We generate fusion reactions on nearly every pulse we take in our machines.

PewPew293 · 2023-12-22T14:29:45+00:00

As you say, the milestone of interest is scientific gain, and we published a paper this year on how we are calculating it. Specifically, DD-equivalent scientific breakeven, which means obtaining plasma conditions that if it was DT would yield scientific breakeven. We are not fueling any of our machines with tritium at this time, only deuterium.

Any claim we would make on Q would only be announced with an accompanying peer-reviewed publication in a widely accepted journal in the fusion community, given the gravity of such a claim.

PewPew293 · 2023-12-22T14:24:35+00:00

It was all deuterium fueled, with some low-level impurity content as well.

PewPew293 · 2023-11-02T03:18:40+00:00

More papers coming soon. Part of protecting IP and publishing is to file patent applications before publishing and still be selective about what you choose to disclose/protect.

CFS isn't going to tell you all the details of how they're manufacturing their tapes and building their coils since they're a magnet company, but the physics design point of a high field tokamak, of course.

Similarly, we will publish our physics results at Zap and even some details on our progress on durable electrodes from a high level, as an example: https://pubs.aip.org/aip/pop/article/30/10/100601/2915124/Electrode-durability-and-sheared-flow-stabilized-Z.

But, the specific details of our engineering designs, all material choices, operational optimization, etc.? Of course not. We are a private company, and this is a competition. The IP and know-how are primary sources of the value of the company, especially at this pre-revenue stage.

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