This impressive-looking piece of equipment lives up to its appearance. The Plasma Kristall-4, to give the device its full name, recreates how atoms interact so we can understand the intricacies of basic physics and chemistry in space. The machine, a joint venture between the European Space Agency and Roscosmos, creates a stew of microparticles — a surrogate for atoms — which are held in a charged plasma (which is just a gas made of ions and electrons). By imposing electrical charges, astronauts can make the microparticles interact with each other. The ESA explains why that's useful:
On Earth the particles are influenced by gravity but in space the particles will behave similarly to charged atoms in a fluid or crystal structure allowing researchers to understand better the hidden interactions of our world.
The Tron-like glow is a result of argon plasma in the PK-4 hardware, which provides the bright purple hue. The device is aboard the ISS, where it runs for up to four days, four times a year.