ASDEX Upgrade is the tungsten-walled divertor 📝Tokamak operated by the Max Planck Institute for Plasma Physics in Garching, Germany, in operation since 1991 and the machine on which much of the boundary physics used to size next-step exhaust systems was measured.
The name expands to Axially Symmetric Divertor Experiment, and the "Upgrade" distinguishes it from ASDEX proper, the 1980–1990 predecessor on which 📝H-mode was discovered in 1982. IPP gives the machine a major plasma radius of 1.65 metres, a plasma volume of 13 cubic metres, a magnetic field of 3.2 📝tesla, a 📝plasma current of 1.4 megaamperes and 27 megawatts of combined 📝neutral beam, 📝ion cyclotron and 📝electron cyclotron heating, in pulses up to about ten seconds. Its distinguishing feature is the wall: since 2007 every 📝plasma-facing component has been clad in 📝tungsten, making it the first tokamak to run a full high-Z wall, the configuration 📝ITER and every power-plant design have since adopted.
That combination — reactor-grade wall materials on a machine small enough to reconfigure — made it the reference device for the 📝scrape-off layer. Two results carry furthest. The 2013 multi-machine scaling of near-scrape-off-layer power width, drawn from ASDEX Upgrade and 📝JET discharges, is the standard basis for sizing a 📝divertor heat load. The 2021 separatrix operational space model of 📝Thomas Eich and P. Manz mapped, from ASDEX Upgrade data, which combinations of density and power at the 📝separatrix give 📝L-mode, H-mode, or the small-📝ELM quasi-continuous exhaust regime. Both are measurements, taken on this machine, and both now do their heaviest work as inputs to machines that have not yet run.