Determining Diamond’s Properties Under Extreme Pressures

Although graphene gives diamond a solid run for its money when it comes to being the most useful assembly of carbon atoms, both have the distinct property of material scientists still trying to figure out all their properties and potential applications. This includes something like the melting curve of diamond and potential phases beyond this diamond lattice phase that occur when exposed to extreme pressures and temperatures. Such as those experienced on a planetary scale and during inertial confinement fusion (ICF).

In this research (paywalled) by researchers at the Lawrence Livermore National Laboratory (LLNL), it was investigated how close theoretical simulations were to physical reality by blasting diamond samples with a laser. This ablated the surface and sent a shockwave through the material that caused it to melt. Using X-ray diffraction data this entire process was followed, elucidating the exact melting temperature under such conditions.

This revealed that previous estimates based on earlier experiments had been off by many hundreds of degrees, giving a far better idea of how diamond responds to such extreme pressures and temperatures. Where such information is very relevant is in fields like planetary science where diamonds can occur naturally and being able to predict their presence can be essential.

The other application, and the primary reason why LLNL does this kind of research is for the sake of ICF at the national ignition facility (NIF), which is the best way to investigate the behavior of e.g. hydrogen isotopes under extreme conditions like those of nuclear weapons.

Unfortunately this research will have no impact on practical power generation using nuclear fusion, as the only viable path there involves forms of magnetic confinement fusion (MCF), but it’s still pretty rad to improve our understanding this carbon form.

Fusion Ignition: What Does The NIF’s 1.3 MJ Yield Mean For Fusion Research?

Earlier this month, Lawrence Livermore National Laboratory (LLNL) announced to the world that they had achieved a record 1.3 MJ yield from a fusion experiment at their National Ignition Facility (NIF). Yet what does this mean, exactly? As their press release notes, the main advancement of these results will go towards the US’s nuclear weapons arsenal.

This pertains specifically to the US’s nuclear fusion weapons, which LLNL along with Los Alamos National Laboratory (LANL) and other facilities are involved in the research and maintenance of. This traces back to the NIF’s roots in the 1990s, when the stockpile stewardship program was set up as an alternative to nuclear weapons testing. Much of this research involves examining how today’s nuclear weapons degrade over time, and ways to modernize the existing arsenal.

In light of this, one may wonder what the impact of these experimental findings from the NIF are beyond merely ensuring that the principle of MAD remains intact. To answer that question, we have to take a look at inertial confinement fusion (ICF), which is the technology at the core of the NIF’s experiments.

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Nuclear Fusion Power Without Regular Tokamaks Or Stellarators

When it comes to nuclear fusion, the most well-known reactor type today is no doubt the tokamak, due to its relatively straight-forward concept of plasma containment. That’s not to say that there aren’t other ways to accomplish nuclear fusion in a way that could conceivably be used in a commercial power plant in the near future.

As we covered previously, another fairly well-known type of fusion reactor is the stellarator, which much like the tokamak, has been around since the 1950s. There are other reactor types from that era, like the Z-pinch, but they seem to have all fallen into obscurity. That is not to say that research on Z-pinch reactors has ceased, or that other reactor concepts — some involving massive lasers — haven’t been investigated or even built since then.

In this article we’ll take a look at a range of nuclear fusion reactor types that definitely deserve a bit more time in the limelight.

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