Constructed at the Max Planck Institute for Plasma Physics in Greifswald, Germany, W7-X is the world's largest and most advanced stellarator. It uses a set of 70 superconducting magnets to generate a magnetic field shaped for good plasma confinement. PPPL has collaborated with this facility for many years, contributing important components including special magnets that lessen the effects of unwanted magnetic fields, a diagnostic that gathers information about the plasma by observing X-rays, and a system that injects pellets to enhance plasma confinement. Current projects include the development of a sensor that detects the loss of fast-moving atomic nuclei, a powder injector, and a system that measures the plasma density and temperature in real time.

Max-Planck-Institut für Plasmaphysik, Tino Schulz - Public Relations Department, Max-Planck-Institut

Constructed at the National Institute for Fusion Science in Toki, Japan, this was the world's first large heliotron, a type of stellarator made with superconducting coils that twist all the way around the device’s vacuum chamber, like a boa constrictor with its prey. PPPL has contributed several components to this facility over the years, including an X-ray diagnostic, a powder injector, and a system that measures the plasma’s density and temperature in real time. Current projects include the design and installation of a powder dropper that can improve plasma performance.

This machine, a small tabletop device designed and built at PPPL, is the first stellarator constructed using an array of permanent magnets, like those used to hold photos, notes or artwork on refrigerator doors. PPPL scientists developed MUSE as a proof-of-concept experiment for the use of permanent magnets in combination with simple straight magnets as an alternative for stellarators that have magnets with extremely complicated shapes that are hard to design and build. Researchers plan to use MUSE to study ways to heat plasma, test new magnetic configurations to improve confinement, and explore the effect of the device on magnetohydrodynamics, the field that treats plasmas as fluids.

JT-60SA is a tokamak in Naka, Japan. Tokamaks are machines that confine plasma in a doughnut shape that scientists refer to as a torus. Completed in 2020, JT-60SA is part of the international "Broader Approach Agreement" that aims to complement the ITER project and accelerate the realization of fusion energy. Jointly built and operated by Japan and Europe, this tokamak will address key physics and engineering issues, including support for preparing ITER operations and optimizing fusion power plants built after ITER.

PPPL, a world leader in designing and constructing diagnostic equipment, is developing an X-ray imaging crystal spectrometer for the JT-60SA. The device will record the intensity of X-ray emissions in the JT-60SA plasma and inform operators of plasma temperature and the velocity of its rotation. These conditions will exceed 100 million degrees Celsius in the core and up to 500 kilometers per second in high-confinement plasma scenarios.

The W Environment in Steady-state Tokamak (WEST) tests designs for ITER, a large-scale, international experiment to generate net power from fusion. WEST is specifically being used to test a component called the divertor. This part of the tokamak helps manage the heat and ash generated during fusion, minimizing contamination of the plasma and protecting its inner walls. PPPL researchers developed an impurity powder dropper for WEST that can add powdered elements, such as boron, to the vessel in a highly precise manner. The French Alternative Energies and Atomic Energy Commission oversees the operation of WEST.

The Madison Symmetric Torus (MST) holds plasma in a doughnutv-shaped magnetic field called a toroid. Researchers use MST to study the behavior of fusion plasma and space plasma. The MST is a reversed field pinch machine, which gives the device different magnetic fields than a tokamak. This makes MST ideal for studying important plasma behaviors such as turbulence and magnetic reconnection, which involves the rearrangement of magnetic fields and is thought to power some solar flares. MST can also produce a fusion-grade, high-temperature plasma. MST plasmas are typically fueled by injecting puffs of deuterium, but other gases, such as hydrogen and helium, can also be used. MST also includes a variety of tools for analyzing the plasma.