With a flash and some sparks, PUFFIN achieves first plasma! After four years of design, fabrication, assembly and commissioning came to an end: last week we fired our first shot on PUFFIN (The PUlser For Fundamental [Plasma Physics] INvestigations). PUFFIN is designed to deliver >500 kA of peak current into a small (egg-sized) volume of a vacuum chamber for a few microseconds. This current will pass through thin metal wires, converting them into hot, dense, and fast-moving plasmas with strong magnetic fields. These plasmas are relevant to fundamental and laboratory astrophysics investigations, as well as magneto-inertial fusion concepts.

We tested PUFFIN using a short-circuit load with a known inductance. Although we did not carry out a specific plasma physics experiment, the intense Ohmic heating on the surface of the electrodes produced significant surface plasma, which appears as a flash of bright light in the brief movie below. The sparks which follow are caused by super-heated fragments of metal whizzing around the vacuum chamber after the current pulse is over.

Although I am leaving MIT soon, this story is far from over – PUFFIN is coming with me to Cornell, but it’ll take a while to get the lab space there ready, so there will be a brief intermission.

I am very grateful to the skilled engineers and technicians at the PSFC, without whom this project could not have succeeded, and to graduate student Thomas Varnish for putting in a huge amount of work on the control and data acquisition systems, as well as during the commissioning process. I gratefully acknowledge the MIT Department of Nuclear Science and Engineering, the Plasma Science and Fusion Center at MIT, the NSF, and the NNSA for supporting the construction of PUFFIN. The capacitor modules for PUFFIN were built by the CEA Gramat, and refurbished for this project, along with new equipment, by ITOPP.