CAREER: Relativistic Electron Driven Magnetic Reconnection

Regents Of The University Of Michigan - Ann Arbor, Ann Arbor MI

Investigators

Abstract

The goal of this project is to test theories of astrophysical magnetic explosions with laboratory plasma studies of magnetic reconnection. Most of the known matter in the universe is in an ionized state, a plasma, comprised of electrons and ions that strongly interact with electromagnetic fields. Magnetic reconnection is an explosive phenomenon that occurs in plasmas where magnetic field lines suddenly rearrange themselves to release large amounts of energy. This has important implications here on Earth for fusion energy schemes and prediction of space weather events that can disable satellites used for communication and navigation. Magnetic reconnection is also theorized to occur around violent astrophysical events such as in the vicinity of gamma-ray bursts or active galactic nuclei where the magnetic fields are very large and the particles move at close to the speed of light. This project will investigate magnetic reconnection under similar conditions in the laboratory and test the accuracy of existing theories. In addition, this award will support efforts to improve the climate for women and other underrepresented groups in Science, Technology, Engineering, and Mathematics (STEM) disciplines in general, and in plasma physics, in particular. Relativistic magnetic reconnection occurs when the energy density of the reconnecting fields exceeds the rest mass energy density. The experiments to be performed will use laser pulses focused to ultra-high intensities to heat a small volume of electrons on a solid foil target to relativistic energies. The electrons are mostly confined to the target surface and expand radially outwards at the speed of light. This generates a very large azimuthal magnetic field. Focusing two laser pulses in close proximity forms oppositely directed magnetic fields in the midplane to form a driven reconnection geometry. Numerical modeling has indicated the conditions created by the laser pulses will satisfy the requirement for accessing the relativistic magnetic reconnection regime. Measurements of the timescale of the reconnection and the characterization of accelerated particle jets will be used to benchmark and test existing theories and numerical models. Further, the education and outreach goal of the project is to help address under-representation of women and minority groups within many fields of STEM, and specifically in plasma physics. This will be done by developing curriculum to educate undergraduate students about unconscious bias and when this may lead to unintentionally discriminatory behavior. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.