Rochester researchers hope to explain how the fields arise during plasma instabilities.
The famous Pillars of Creation in the Eagle Nebula – a stellar nursery – are believed to result from the hydrodynamic instabilities created when plasmas are exposed to the high-intensity light of neighboring stars.
Something very similar happens – on the smallest scale – when materials are imploded by converging laser beams during high-energy-density physics and fusion experiments at the University of Rochester’s Laser Energy Laboratory.
“You’re beaming the lasers, you’re evaporating mass from the surface and you’re pushing everything radially inward, and you have these hydrodynamic instabilities that have similar modulations to the pillars,” says Hussein Aluie, associate professor of mechanical engineering at the Hajim School of Engineering in Rochester & Applied Sciences.
To what extent do plasmas subject to instabilities generate magnetic fields, and how do these magnetic fields further affect the plasma instabilities? “It is well known that magnetic fields can strongly influence the behavior of plasmas,” says Aluie, “but the mechanisms for the self-generation and amplification of magnetic fields in different types of plasma remain a mystery.”
With funding from a $390,000 National Science Foundation grant, Aluie will solve this puzzle with Co-PI Riccardo Betti, LLE Principal Investigator and Robert L. McCrory Professor, and Fernando Garcia-Rubio, LLE Assistant Scientist and in Aluie’s Turbulence and Complex Flow, tackle group, which developed the theory for this work. The goal is to identify the main mechanisms by which magnetic fields are self-generated in irradiated plasmas that are subject to instabilities. The work includes theoretical analyzes and numerical simulations.
“Based on previous research that we and others have done, which we hope to develop further, we know that these magnetic fields, even if initially weak, grow rapidly,” says Aluie.
“They affect the way heat moves around the surface of the plasma and mass evaporates, changing the way the instability forms. And in the case of fusion experiments, it changes the way the target becomes unstable.”
A better understanding of this process could help scientists get closer to fusion as a source of unlimited energy and better understand the formation of nebulae and other astrophysical bodies, says Aluie.
The Flash Center, dedicated to computer simulations to improve understanding of astrophysics, plasma science, high energy density physics and fusion energy, has relocated from the University of Chicago to Rochester.
category: Science & Technology