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Welcome to the afterpop. In our previous episode, we got
to talk with Ryan Serpa, A Division One Purdue University
swimmer and nuclear engineer. Over the summer, Ryan did an
internship at Sandia National Laboratories.
So now we're going to go into something that he spoke of
within that episode, the Z machine.
Imagine a machine for a few billions of a second unleashes
more power than all of the electric grids on Earth
combined. That's the Z machine at Sandia,
built not to power cities but to recreate the immense heat,
pressure and X-ray intensity of stellar interiors, planetary
cores, and nuclear detonations. In those fleeting moments,
scientists can test materials, probe fusion technologies, and
validate computer models for nuclear security.
So what is the Z machine, why was it built, and what's it for?
There are three intertwined motivations.
First, national security and the nuclear stockpile stewardship.
As nuclear weapons age, we want to know how materials behave
under extreme conditions. Temperature, pressure, shock,
those types of things. The Z machine let's scientists
simulate those conditions in a controlled lab setting.
Next, high energy density physics and basic science.
It's a tool for exploring matter under extreme states, like I
said, in stars, giant planets, or astrophysical explosions.
Pretty cool. And lastly, fusion as well as
future energy research because it can compress heat and can
find plasmas at extreme rates. It's used in experimental fusion
approaches, notably magnetized linear inertial fusion, to try
and hit conditions where fusion yields more energy than input.
In short, it's an extreme environment created to push the
boundaries across defense, material science, and fusion.
Now we're going to go into kind of how it works, sort of.
Imagine you have a tiny balloon of gas.
If you press it slowly, the gas leaks and the heat dissipates.
But if you slam your hands together fast, the gas
compresses, heats and reaches extreme conditions before it can
escape. The Z machine is like that, but
hyper accelerated and electrified.
Now we'll move into the steps of how it works.
First, it stores energy. The Z machine charges up a Bank
of capacitors over 2 minutes, storing around 10 mega joules.
But what does that mean? 10 mega joules is about 2.4kg or
5 lbs of TNT. Next discharge in a flash, AKA
pulsed power. When everything is ready, the
stored energy is dumped into a few 10s to hundreds of
nanoseconds. That's billionths of a second.
That concentrates the energy in time, producing gigantic
instantaneous power on the order of 80 terawatts.
But what's 80 terawatts? 80 terawatts is 80 trillion
watts. For context, the entire planet's
electrical grids produce around 25 terawatts at any given
moment. That means for a few billionth
of a second the Z machines pulse power outshines all human
electricity production combined. That's insane. 3Z pinch
implosion, magnetic compression. The high current flows through a
load, often a fine wire array, a metal cylinder, or another
structure. The current generates a
magnetic. Field which?
Exerts an inward pinching force on the plasma.
This implodes the material inward, compressing and heating
it drastically. This is the Z pinch concept.
Current is moving along the Z axis to produce a radial pinch.
Z pinch 4X ray burst. An extreme environment.
As the implosion peaks, enormous densities, temperatures,
pressures, and X-ray fluxes are achieved.
The target may emit a burst of X-rays, and researchers measure
how materials behave under those stresses. 5 Diagnostics and data
in that few nanosecond moment, A battery of diagnostics.
X-ray detectors. Spectrometers, particle
detectors, captures, signatures, everything from temperature,
density, radiation, and shocks. That data helps validate
computational models and test hypothesis about fusion and
material behavior. Reset and repeat after a shot,
components are refurbished. Reset and the cycle repeats.
The Z machine typically fires 200 shots per year.
I think of it this way. You know, in those superhero
movies, when the hero is about to take off her flight, they
slowly bend down, building up all of this potential energy.
And then in an instant they take off.
A Sonic boom is heard, dust is flying all around, and usually
some kid with that ice cream cone is looking at Superman
flying in the air. But with the Z machine, there is
a sensory impact. You could actually feel it
during a firing. Sandia engineers report that
shock waves from the electromagnetic pulse and rapid
air displacement can be felt and heard miles away.
The entire facility rumbles like a small earthquake.
Some workers describe the effect as a low frequency boom.
Not dangerous, but unmistakable. So what are some of the
challenges and caveats with doing this type of research?
First, instabilities and mixing. Plasmas are famously unstable.
Just check out the Rayleigh Taylor instability, plasma
turbulence, things like that. Maintaining symmetry and
preventing mixing is a major engineering challenge in maglev
configurations. For example, avoiding liner
breakup and controlling instabilities is crucial.
Short confinement time and fast disassembly.
Because things are compressed so fast, the plasma tends to fly
apart very quickly. The fusion burn must occur
before the system disassembles. That's why pulses, magnetic
fields and preheating schemes are tightly timed.
Scaling to net energy gain. So far the Z machine is not a
commercial fusion device, it's a research tool.
Achieving break even where fusion output is greater than
energy input is extremely hard. The additional complexity of
capturing and sustaining the fusion output, handling heat and
doing that repeatedly is non trivial.
Lastly, where repeatability and cost, the extreme forces, shock
waves and mechanical stresses on the device components require
refurbishing and careful design. The cost per shot in operational
overhead can be pretty high. So how does the Z machine relate
to the commercial market? Here are some recent advances
with the first light fusion experiment.
They recently used the Z machine to test their amplifier
technology and achieve record pressures around 10 times the
pressures at the Earth's core. Next, ongoing development of
future versions. Sandia is exploring upgrades to
allow higher shot rates and better performance.
Then there's the Z fundamental science program.
It's where academic and industry groups can propose experiments
on the Z to explore new regimes of high energy density physics.
Thank you so much for listening to the after pop where we break
down. What the heck is AZ machine?
In the blink of a cosmic eye, the Z machine stabs a target
with electrical power far beyond everyday comprehension.
Every shot is a fleeting feeder of extremes.
Plasma squeezed to stellar intensities, X-rays screaming
outward, and atoms push to the brink.
Yet for all of its power, Z is not a power plant.
It's a microscope on extremes, a place where physics is pushed,
where materials crack, energies collide, and all of our models
are stress tested. When fusion becomes practical,
it may be because we first tamed a machine like Z and understood
the chaos behind the pulse. You've been listening to Nega
Diggler. If you've enjoyed this episode,
please share it with a friend. The next shot could light the
path to new energy or deeper discovery.
Until next time, stay curious.