The device

The Material Plasma Exposure eXperiment (MPEX) is a next-generation linear plasma device that will support the study of the way plasma will interact long-term with the components of future fusion reactors—in particular, the divertor, the power and particle “exhaust system” of a fusion reactor.

MPEX’s design represents a shift from the historical direction of the plasma-material interaction field, which for many years focused on the effect that materials had on plasma, but not on the effect that plasma had on materials.

Below is a list of MPEX’s parameters and performance goals:



Electron density at the target (ne)

Up to 2 × 1021 m-3

Temperature of electrons at the target (Te)

Up to 15 eV

Ion temperature at the target (Ti)

Up to 20 eV

Magnetic field at the target (B)

1 T

Plasma diameter

3–10 cm

Ion flux at the target (Gi)

>1024 m-2s-1

Minimum angle of B to target

Power flux (q), parallel

Up to 40 MW/m2

q, perpendicular

10 MW/m2

Total ion fluence

Up to 1031 m-2