HIDRA’s Many Uses

Within NPRE, the HIDRA facility will be used for a multitude of scientific investigations, including to:

• Evaluate whether a full toroidal liquid metal loop can operate in a toroidal machine
• Test low recycling regimes
• Determine whether deuterium can be removed and recycled easily
• Provide a test bed for advanced materials testing, processing, and development of in-situ diagnostics to measure the time-scale of plasma-material interactions and how material surfaces respond to the fusion plasma
• Design an advanced multi-user facility named HIDRA-MAT for innovative materials testing and processing
• Address fundamental problems of edge plasma physics
• Calibrate numerical kinetic models of cross-field electron transport in partially ionized conditions
• Extend CPMI’s investigation of lithium walls for small-scale, linear fusion devices to a medium-sized toroidal device
• Explore the science of continuous vapor shielding
• Address fundamental questions regarding the survivability of materials exposed to high heat fluxes

HIDRA is unique in that it combines a tokamak and a stellarator.

A tokamak is a torus- or donut-shaped vacuum chamber surrounded by magnetic coils that create a toroidal magnetic field. A second set of coils along the axis, or the hole in the donut shape, can create a plasma current, which makes an additional magnetic field, effectively twisting it throughout the vessel. This circulates the particles, confining them to the center of the ring, to prevent the plasma from escaping. A drawback of the tokamak concept is it has to operate in pulsed mode because the plasma current is induced by an increasing current in the center coils. Once the voltage driving the current reaches its maximum value, the pulse stops.

A stellarator, on the other hand, can create an indefinite plasma, albeit not at as high a temperature. Also based on a donut-shaped vessel, a stellarator relies entirely on meticulously designed coils to generate a helically-shaped magnetic field containing the plasma.