An overview of recent results from the PUFFIN group at MIT
POSTER
Abstract
We present recent work by the PUFFIN group at MIT, including:
Guide field reconnection on MAIZE, using dual exploding wire arrays with external applied magnetic fields or with tilted wire arrays to embed an out-of-plane magnetic field in the reconnection layer. We observe that high external fields are frozen out of the plasma flows, preventing the formation of a reconnection layer, but with the tilted wire arrays the guide field is embedded in the flows.
Exploding planar wire arrays on COBRA, which were scaled to match the current per wire, wire spacing, and driving magnetic field of an exploding cylindrical wire array on Z as a scaled experiment of the ablation of thick wires. We observe that 75 um aluminium wires ablate well, but 100 um wires do not.
Radiatively cooled reconnection experiments on Z, where we observe 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.
The status of the new PUFFIN facility at MIT, a new 1 MA peak current, 1.5 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.
Guide field reconnection on MAIZE, using dual exploding wire arrays with external applied magnetic fields or with tilted wire arrays to embed an out-of-plane magnetic field in the reconnection layer. We observe that high external fields are frozen out of the plasma flows, preventing the formation of a reconnection layer, but with the tilted wire arrays the guide field is embedded in the flows.
Exploding planar wire arrays on COBRA, which were scaled to match the current per wire, wire spacing, and driving magnetic field of an exploding cylindrical wire array on Z as a scaled experiment of the ablation of thick wires. We observe that 75 um aluminium wires ablate well, but 100 um wires do not.
Radiatively cooled reconnection experiments on Z, where we observe 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.
The status of the new PUFFIN facility at MIT, a new 1 MA peak current, 1.5 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.
*This work was supported by the NSF and NNSA through PHY2213898, and through an NSF EAGER award PHY2108050.
Publication: 1. Datta, R. et al. Plasma flows during the ablation stage of an over-massed pulsed-power-driven exploding planar wire array. arXiv:2306.03304 (2023) doi:10.48550/arXiv.2306.03304.
2. Datta, R. et al. The structure of 3-D collisional magnetized bow shocks in pulsed-power-driven plasma flows. Journal of Plasma Physics 88, 905880604 (2022).
3. Datta, R. et al. Time-resolved velocity and ion sound speed measurements from simultaneous bow shock imaging and inductive probe measurements. Review of Scientific Instruments 93, 103530 (2022).
Presenters
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Jack D Hare
- MIT PSFC