An overview of recent results from the PUFFIN group at Cornell

We present recent work by the PUFFIN group at Cornell (formerly at MIT), including:

Radiatively cooled reconnection experiments on Z, where we observed the formation and collapse of a reconnection layer using a suite of X-ray diagnostics which reveal the existence of bright hotpots within the layer which correspond to plasmoids in our 3D MHD simulations. We also observed the structure and evolution of the reconnection layer using laser shadowgraphy.

Guide field reconnection experiments on MAIZE and COBRA, using tilted wire arrays which embed an out-of-plane magnetic field in the reconnection layer. We observe that the reconnection layer has a quadrupolar density structure on global scales (>10 d_i) indicative of the interplay between the Hall field created by two-fluid effects and the guide field. We use optical Thomson scattering to observe localised heating and acceleration within this structure.

Oblique shock experiments on COBRA, which used an exploding wire array to drive magnetised plasma flows to interact with oblique targets. The shock opening angles are measured using shadowgraphy and interfeometry, and we demonstrate the importance of radiative cooling in the shock structure.

The status of the new PUFFIN facility at MIT (en route to Cornell), a new 700 kA peak current, 2 us rise time pulsed-power generator, which is designed to drive plasmas in a quasi-steady-state suitable for studying the growth of instabilities and the development of magnetised turbulence.