FM12p.54 — Laboratory experiments investigating magnetic field production via the Weibel instability in interpenetrating plasma flows

Date & Time

Aug 4th at 6:00 PM until 6:00 PM




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Author(s): Channing Huntington2, Frederico Fiuza6, James Steven Ross2, Alex Zylstra3, Brad Pollock2, R. Paul Drake7, Dustin Froula9, Gianluca Gregori8, Nathan Kugland1, Carolyn Kuranz7, Matthew Levy8, Chikang Li3, Jena Meinecke8, Richard Petrasso3, Bruce Remington2, Dmitri Ryutov2, Youichi Sakawa4, Anatoly Spitkovsky5, Hideke Takabe4, David Turnbull2, Hye-Sook Park2

Institution(s): 1. Lam Research Corporation, 2. Lawrence Livermore National Lab, 3. Massachusetts Institute of Technology, 4. Osaka University, 5. Princeton University, 6. Stanford University, 7. University of Michigan, 8. University of Oxford, 9. University of Rochester

Astrophysical collisionless shocks are often associated with the presence of strong magnetic fields in a plasma flow. The magnetic fields required for shock formation may either be initially present, for example in supernova remnants or young galaxies, or they may be self-generated in systems such as gamma-ray bursts (GRBs). In the case of GRB outflows, the intense magnetic fields are greater than those seeded by the GRB progenitor or produced by misaligned density and temperature gradients in the plasma flow (the Biermann-battery effect). The Weibel instability is one candidate mechanism for the generation of sufficiently strong fields to create a collisionless shock. Despite their crucial role in astrophysical systems, observation of the magnetic fields produced by Weibel instabilities in experiments has been challenging. Using a proton probe to directly image electromagnetic fields, we present evidence of Weibel-generated magnetic fields that grow in opposing, initially unmagnetized plasma flows from laser-driven laboratory experiments. Three-dimensional particle-in-cell simulations reveal that the instability efficiently extracts energy from the plasma flows, and that the self-generated magnetic energy reaches a few percent of the total energy in the system. This result demonstrates an experimental platform suitable for the investigation of a wide range of astrophysical phenomena, including collisionless shock formation in supernova remnants, large-scale magnetic field amplification, and the radiation signature from gamma-ray bursts.
This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.