Baking the perfect pie one piece at a time: PPPL makes progress on central magnet of NSTX‑U
https://www.pppl.gov/news/2024/baking-perfect-pie-one-piece-time-pppl-makes-progress-central-magnet-nstx%E2%80%91uBaking the perfect pie one piece at a time: PPPL makes progress on central magnet of NSTX‑U
Jeanne Jackson DeVoe
Oct. 25, 2024
The
U.S. Department of Energys
Princeton Plasma Physics Laboratory (PPPL) achieved a major milestone recently when it completed the intricate process of building the first quadrant of the magnet at the heart of the
National Spherical Torus Experiment-Upgrade (NSTX-U).
PPPL is assembling two high-current magnets to create the toroidal field-ohmic heating coil (TF-OH) bundle. The magnets make up the core of the NSTX-U, similar to the core of an apple. They are designed to produce the highest magnetic field strength of any large spherical torus.
The toroidal field (TF) coil is a 19-foot tall inner magnet resembling a telephone pole that carries up to four megaamps of electric current or 4 million amps to stabilize and confine the hot plasma in fusion experiments. The outer magnet, the ohmic heating (OH) coil, is a 4-kilovolt magnet that wraps around the TF coil like thread around a bobbin. It uses up to 24,000 amps to induce an electric field that drives an electric current within the vessel and helps heat the plasma.
These magnets are critical to the NSTX-U experiment, and the team has been laser focused on this assembly, said Steve Cowley, Laboratory director. Constructing the first quadrant is a big achievement.