Progress on the Upgrade of the Helically Symmetric Experiment

The helically symmetric experiment (HSX) is an optimized stellarator using quasi-helical symmetry (QHS) of the magnetic fields to confine its plasmas. It has been in operation since 2001 and has successfully demonstrated minimized neoclassical transport and relevant turbulence physics. HSX performance is limited by the frequency of its electron cyclotron heating (ECH) source, which does not allow plasma densities higher than 1x1019 m-3. In order to triple this limit, HSX is upgrading its facilities to operate with a gyrotron recently acquired from the Max Planck Institute for Plasma Physics in Germany. All conceptual design work is now complete, and most engineering has been finalized. Fabrication, installation, and commissioning is now fully under way. Magnet power supplies have been upgraded and commissioned, and a new ECH power supply is currently being installed. Gyrotron and transmission line parts are being fabricated and installed. First plasma is expected by the end of 2021.