Overview of the Early Campaign Diagnostics Planned for the SPARC Tokamak

The SPARC tokamak plans to begin operations in mid-2025 and execute a series of mission-driven campaigns, the first of which is to demonstrate net energy, Q_fus > 1, and then move to close tokamak science gaps required to complete the design of ARC. Accomplishing this will require a plasma diagnostic set that can be used for real-time control, inter-shot learning and enable in-depth analysis. Planned tools cover approximately 40 sub-systems including magnetics, interferometry, neutral pressure, x-ray to visible spectroscopy, camera imaging, bolometry, neutron imaging and spectroscopy, Thomson scattering, ECE, reflectometry, Langmuir probes and temperature and strain sensing for in-vessel components. Capabilities and requirements for these diagnostics are outlined at a high level, along with their time-phasing relative to SPARC’s planned operational milestones. Examples of ongoing physics and engineering design activities are presented in order to highlight how diagnostics interface with fixed electrical and optical feedthroughs, a series of replaceable midplane (x9) and off-midplane (x20) port-plugs and transmit neutrons, photons and electrical signals from the Tokamak Hall via 31 configurable penetrations to five dedicated diagnostic laboratory spaces.