ECE Seminar: Jack Hare – Pulsed-power as a Driver for Nuclear Fusion
Abstract: Early in the history of controlled nuclear fusion research, Lawson demonstrated that fusion reactions can generate net energy when the product of the density (n) and plasma energy confinement time (t) exceeds nt> 10^20 s/m^3, with a temperature of 25 keV. This remarkable result has two profound consequences: firstly, at 25 keV the fusion fuel (typically isotopes of hydrogen) will be in the plasma state, which is very hard to create and confine, and secondly, a huge range of solutions are permitted, from very dense, short-lived plasmas, to very sparse, long-lived plasmas. This wide parameter space has led to a diverse range of fusion reactor concepts, the most successful of which use large, superconducting magnets to confine sparse (n~ 10^20) plasmas for seconds or use intense laser pulses to transiently compress the plasma to very high densities (n~10^30) for fractions of a nanosecond.
These two approaches, respectively called magnetically and inertially confined fusion, both require expensive drivers to reach the required temperatures and densities. Pulsed power offers a third and potentially far cheaper path, in which the application of intense electrical current is used either to Ohmically heat the plasma or to apply intense magnetic pressure to compress it. However, the plasma physics in this intermediate regime is not well understood: instabilities within the plasma, caused by the interaction of the plasma with the magnetic field, hydrodynamic instabilities, or localized runaway cooling, may reduce the plasma lifetime below the value needed for net energy gain. In this talk, I will discuss the role that university-based experiments play in understanding this physics, providing data to test the theories and validate the simulations used to design novel fusion reactor concepts, as well as how developments in pulsed power can lead to new applications for clean energy.
Bio: Prof. Jack Hare is the Gale Career Development (1929) assistant professor in the Department of Nuclear Science and Engineering at MIT. He graduated from the Natural Sciences Tripos at the University of Cambridge in 2011, followed by a Master’s degree at Princeton University in the Graduate Program in Plasma Physics in 2013. He carried out his PhD research at Imperial College London, supervised by Prof. Sergey Lebedev on the 1.4 MA MAGPIE generator, graduating in 2017, followed by postdoctoral appointments at Imperial College (2017-2019 and 2020) and the Max -Planck Institute for Plasma Physics in Garching, Germany (2019). He started his new research group based around the PUFFIN pulsed-power generator at MIT in 2021.
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