The eyes and ears of ITER

Surrounded by lengths of metal pipe, batteries, a water kettle, and a few small magnets, Diagnostic Division Head Michael Walsh undertook to explain, in lay terms, the diagnostics planned for ITER during an Inside ITER seminar on Thursday, 10 November.

 

He used his props to illustrate the ways in which ITER's 45 diagnostic systems will provide precious feedback for the control of the plasma, for machine protection, and for an understanding of the physics during operation.

 

"Not having diagnostics in the machine would be like flying in the dark," Michael said. "We couldn't 'see' what was happening on the inside. In fact, we couldn't even start the machine without the information that diagnostics will provide to manage operational parameters like coil current."

 

A basic set of diagnostics will be required from day one in ITER to provide the measurements that will give the green light—a sort of "bill of clean health"—for operation to begin. "But from day two forward, explains Michael, "we'll need much more information than that." ITER's size and scale will create special challenges for the diagnostic systems: ITER's plasma volume is ten times that of the largest operating tokamak JET, its plasma current up to three times greater, its pulse ten to one hundred times longer, and its neutron environment much harsher.

 

"Challenge is just an opportunity," says Michael. "We are tackling the challenges in a coordinated way, with a capable team within the ITER community and support from many places around the world."