News on China's scientific and technological development.

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taxiya

Brigadier
Registered Member
Wuhun said:
SIOM has developed gratings for 50 petawatt-class high-power laser system that has an energy-loading performance of >7 times compared to the Lawrence Livermore Lab's National Ignition Facility's gratings developed in 2022. The PI is Shao Jianda who is the director of SIOM.
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LLNL NIF leads the US inertial confinement fusion project. So they probably uses the same gratings in their laser based nuclear fusion.
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The achievement in high power laser is great in itself, but I don't see how laser based nuclear fusion could possibly work, let alone if China is working on an active program. I would be glad to be proven wrong though.

Here is what I know of. The high power laser demonstrated by the US is focused on a tiny spot that create temperature and pressure enough to fusion for that tiny volume of fuel. So far I haven't seen any paper on schemes that maintains a sustained process. It is a miniturazed hydrogen bomb as the system was designed for weapon research. If the US actually serious of this solution, I would expect to see some publication on how they intend to do it.
 
siegecrossbow

siegecrossbow

General
Staff member
Super Moderator
taxiya said:
The achievement in high power laser is great in itself, but I don't see how laser based nuclear fusion could possibly work, let alone if China is working on an active program. I would be glad to be proven wrong though.

Here is what I know of. The high power laser demonstrated by the US is focused on a tiny spot that create temperature and pressure enough to fusion for that tiny volume of fuel. So far I haven't seen any paper on schemes that maintains a sustained process. It is a miniturazed hydrogen bomb as the system was designed for weapon research. If the US actually serious of this solution, I would expect to see some publication on how they intend to do it.
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It’s for nuclear bomb research. Anything other than magnetic confinement is impractical for power generation.
 
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dingyibvs

Senior Member
taxiya said:
The achievement in high power laser is great in itself, but I don't see how laser based nuclear fusion could possibly work, let alone if China is working on an active program. I would be glad to be proven wrong though.

Here is what I know of. The high power laser demonstrated by the US is focused on a tiny spot that create temperature and pressure enough to fusion for that tiny volume of fuel. So far I haven't seen any paper on schemes that maintains a sustained process. It is a miniturazed hydrogen bomb as the system was designed for weapon research. If the US actually intend for a laser based fusion, I would expect to see some publication on how they intend to do it.
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I don't really see it either. And the energy input/output calculations are all crap. They use the energy of the laser as the nominator rather than the electrical energy required to generate the laser, and they use the thermal energy as denomiator rather than electrical energy. Talk about misleading.
 
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Wuhun

New Member
Registered Member
taxiya said:
The achievement in high power laser is great in itself, but I don't see how laser based nuclear fusion could possibly work, let alone if China is working on an active program. I would be glad to be proven wrong though.

Here is what I know of. The high power laser demonstrated by the US is focused on a tiny spot that create temperature and pressure enough to fusion for that tiny volume of fuel. So far I haven't seen any paper on schemes that maintains a sustained process. It is a miniturazed hydrogen bomb as the system was designed for weapon research. If the US actually serious of this solution, I would expect to see some publication on how they intend to do it.
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The gratings are primarily developed for China's 100 petawatt-class high power laser system which is now currently under development. This grating system designed for sub 50 petawatt-class high power laser system is probably a scaled down version or an approach towards the 100 petawatt-class direction.

As for fusion, every serious country/teams are focusing on magnetic confinement fusion except America and China and to some extent Japan. They are focusing on both. Even if ICF eventually turns out to be a failed approach both America and China have comprehensive technological foundation to have one of their premier lab work on it. As you've pointed out, much of the R&D on ICF can also be used to develop next-generation nuclear weapon system.

Similarly the grating system developed primarily for high-power laser system can also be used for ICF. Since LLNL is the leading team in America in both high power laser system and ICF then they probably used the same grating system they developed for their high power laser system in their ICF breakthrough.
 
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BlackWindMnt

Captain
Registered Member
dingyibvs said:
It says several times of BT, which is only a couple Mb/s, so not nearly enough bandwidth to replace wifi. Apparently it's enough for lossless audio though, which for audiophiles is absolutely a deciding factor over BT. You don't spend hundreds/thousands on DACs, Amps, and headphones just to listen to lossy audio like aptx, which is why high end headphones are still wired. If NearLink can do lossless, even if compressed lossless audio wirelessly then it could take over the whole high end market.
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Nearlink also uses less energy so I expect wireless headsets and air pods will also gain some more battery life with the tech.

Nearlink seems to really fill in a pillar in Huawei's IoT vision of the consumer home. N + 1 vision or something like that where you have N IoT or other devices connected and controlled by your +1 device could be desktop, laptop or phone.
 
mossen

mossen

Junior Member
Registered Member
But export controls on most dual-use goods, particularly commodities goods like chips, harm the United States. The best policy is to export chips to China, but not their production technology. No one want to be soft on China, but restrictions on chip exports do more harm than good in tech competition.'
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This sounds like "keep the DUV/EUV sanctions intact but let the GPUs from Nvidia flow freely". Probably a smarter take than current policy, but I suspect too little too, late even if implemented.
 
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