Boffins produce plasma at two billion kelvins

Very hot stuff from the Z machine

Security for virtualized datacentres

Scientists at the Sandia National Nuclear Security Administration laboratory have produced plasma at a sizzling two billion kelvins - hotter than a star's interior - although they're not quite sure how they did it.

The "unexpectedly hot output", as the Sandia blurb puts it, is the spawn of the mighty Z machine (seen firing below as "arcs and sparks formed at the water-air interface travel between metal conductors" - crikey). The beast is the world's most powerful X-ray generator tasked mainly with "new experimental environments to help validate computer codes responsible for maintaining a reliable nuclear weapons stockpile safely and securely".

The Z machine

Sandia's explanation of the Z machine's normal operation is this:

20 million amps of electricity pass through a small core of vertical tungsten wires finer than human hairs. The core is about the size of a spool of thread. The wires dissolve instantly into a cloud of charged particles called a plasma.

The plasma, caught in the grip of the very strong magnetic field accompanying the electrical current, is compressed to the thickness of a pencil lead.

At that point, the ions and electrons have nowhere further to go. Like a speeding car hitting a brick wall, they stop suddenly, releasing energy in the form of X-rays that reach temperatures of several million degrees — the temperature of solar flares.

The latest breakthrough, however, "was obtained in part by substituting steel wires in cylindrical arrays 55mm to 80mm in diameter for the more typical tungsten wire arrays, approximately only 20mm in diameter. The higher velocities achieved over these longer distances were part of the reason for the higher temperatures".

That partial explanation doesn't answer all of Sandia's questions, though. First up, the X-ray output was "as much as four times the expected kinetic energy input" meaning that some extra energy must have been pumped into the equation from somewhere.

Secondly, "high ion temperatures were sustained after the plasma had stagnated — that is, after its ions had presumably lost motion and therefore energy and therefore heat — as though yet again some unknown agent was providing an additional energy source to the ions".

Sandia project lead Chris Deeney summed it up with: "At first, we were disbelieving. We repeated the experiment many times to make sure we had a true result and not an 'Ooops'!"

A possible explanation for the mystery came from Sandia consultant Malcolm Haines of Imperial College in London, which appeared in the 24 February Physical Review Letters. In summary, Haines theorised that "the rapid conversion of magnetic energy to a very high ion plasma temperature was achieved by unexpected instabilities at the point of ordinary stagnation" (where the plasma's particles "should have been unable to travel further"). Haines postulates "some unknown energy" which continued to push back against the magnetic field for around 10 nanoseconds.

In other words: "Sorry, we don't exactly know what's going on but we'll get back to you soon." Watch this space. ®


Our regular science readers will remember that the Z machine was put forward as a possible candidate to power the theoretical hyperdrive. Looking at the photo above, we reckon we'll easily be nipping off to Mars in three hours by 2010.

Remote control for virtualized desktops

More from The Register

next story
Voyager 1 now EIGHTEEN LIGHT HOURS from home
Almost 20 BEEELION kilometres from Sol
Ex-Soviet engines fingered after Antares ROCKET launch BLAST
Speculation rife, but Orbital claims it's too early to tell
MEN: For pity's sake SLEEP with LOTS of WOMEN - and avoid Prostate Cancer
And, um, don't sleep with other men. If that's what worries you
Jim Beam me up, Scotty! WHISKY from SPAAACE returns to Earth
They're insured for $1m, before you thirsty folks make plans
Er, we think our ISS launch beats your fishing expedition
NASA: Spacecraft crash site FOUND ON MOON RIM
'What fun!' exlaims NASA boffin who found the LADEE
Comet Siding Spring revealed as flying molehill
Hiding from this space pimple isn't going to do humanity's reputation any good
BAE points electromagnetic projectile at US Army
Railguns for 'Future fighting vehicle'
prev story


Why and how to choose the right cloud vendor
The benefits of cloud-based storage in your processes. Eliminate onsite, disk-based backup and archiving in favor of cloud-based data protection.
A strategic approach to identity relationship management
ForgeRock commissioned Forrester to evaluate companies’ IAM practices and requirements when it comes to customer-facing scenarios versus employee-facing ones.
High Performance for All
While HPC is not new, it has traditionally been seen as a specialist area – is it now geared up to meet more mainstream requirements?
Top 5 reasons to deploy VMware with Tegile
Data demand and the rise of virtualization is challenging IT teams to deliver storage performance, scalability and capacity that can keep up, while maximizing efficiency.
Mitigating web security risk with SSL certificates
Web-based systems are essential tools for running business processes and delivering services to customers.