When it comes to promising forms of energy, nuclear fusion checks all the boxes: it’s clean, abundant, continuous and safe.
It occurs when the light nuclei of two atoms combine to form a heavier nucleus, releasing a large amount of energy.
For fusion reactions to occur in a controlled manner, huge reactors are needed in the form of giant rings that are filled with magnets to create magnetic fields where atomic particles buzz around and dance like a swarm of bees.
Hard to take a picture? The good news is that you can now watch a live simulation of this kind of reactor – called a tokamak – thanks to amazingly realistic 3D visualization technology.
At EPFL, the Laboratory for Experimental Museology (EM+) specializes in this technology and has developed a program to transform terabytes of data generated from tokamak simulations and testing carried out by EPFL’s Swiss Plasma Center (SPC) into an immersive 3D visualization experience.
For the general public, visualization is a way into a circle of fireworks illustrating a possible future source of energy; for scientists, it is a valuable tool that makes the complex phenomena of quantum physics tangible and helps them understand the results of their calculations.
The pictures are so accurate that they show the wear and tear
The 3D visualization – a panorama measuring 4 meters high and 10 meters in diameter – is a faithful reproduction of the interior of EPFL’s Variable Configuration Tokamak (TCV), rendered in such stunning detail that it rivals even the highest quality gaming experiences.
The experimental reactor was built more than 30 years ago and is still the only one of its kind in the world.
“We used the robot to generate ultra-high-precision scans of the inside of the reactor, which we then compiled to create a 3D model that replicates its components down to their texture,” says Samy Mannane, a computer scientist at EM+.
“We were even able to capture the wear of the graphite tiles lining the reactor walls, which are exposed to extremely high temperatures during TCV test runs.”
SPC engineers have provided equations to calculate exactly how the quantum particles are moving at any given moment in time. The EM+ researchers then incorporated these equations along with the reactor data into their 3D visualization system. The catch is that all calculations must be done in real time.
“For the system to produce just one image, it has to calculate the trajectories of thousands of moving particles at a rate of 60 times per second for each eye,” says Mannane.
This massive numbering is done by five 2-GPU computers that EM+ acquired for this project. The output from the computers is fed to the panorama’s five 4k projectors.
“We were able to build our system because of advances in infographic technology,” says Sarah Kenderdine, a professor who leads EM+. “Just five years ago this would have been impossible.”
The result is realistic images of stunning quality. You can see the injection device that deposits particles into the tokamak, as well as graphite tiles capable of withstanding temperatures of over 100 million degrees Celsius.
And the scale of it all is impressive. To give you an idea, part of the visualization is an image of a person – the reactor is roughly twice as big. As the simulation gains momentum, the viewer feels quite small as thousands of particles run around, spinning, twisting and chasing each other.
Electrons are in red; protons are green; and the blue lines indicate the magnetic field. Users can adjust any of the parameters to see a specific part of the reactor at a chosen angle, with near-perfect rendering.
SPC director Paolo Ricci explains: “Visualization techniques are quite advanced in astrophysics, mainly thanks to planetariums. But in nuclear fusion, we are just starting to use this technology – especially thanks to the work we are doing with EM+.”
Based on SPC’s excellence in this field, EPFL participates in the International Thermonuclear Experimental Reactor (ITER) project and is a key member of the EUROfusion consortium.
In fact, EPFL has been chosen to host one of the consortium’s five Advanced Computing Hubs, providing researchers involved in this EU-funded project with an advanced tool to visualize their work.
A combination of output and art
Kenderdine says the biggest challenge was “extracting tangible information from such a huge database and creating a visualization that is accurate, coherent and ‘real’ – even though it’s virtual.
“The result is extraordinary, and I would even say beautiful, and it gives scientists a useful tool that opens up a number of possibilities.”
“The physics behind the visualization process is extremely complicated,” says Ricci.
“Tokamaks have many different moving parts: particles with heterogeneous behavior, magnetic fields, waves to heat the plasma, externally injected particles, gases, and more.
“Even physicists have trouble sorting it all out. The visualization developed by EM+ combines the standard output of simulation programs—basically a table of numbers—with the real-time visualization techniques the lab uses to create a video game-like atmosphere.”
In addition to SPC and EM+, three other EPFL groups participate in the Advanced Computing Hub: the Swiss Data Science Center, the Institute of Mathematics and the Scientific IT & Application Support Unit (SCITAS).
This article was originally published by EPFL.