Electron acceleration in laboratory-produced turbulent collisionless shocks
Name
19ja107_full.pdf
Size
9.01 MB
Format
Adobe PDF
Checksum (MD5)
09a022b60dd89ff32af3e3498e75d6f1
Author(s)
Fiuza, F.
Swadling, G.F.
Grassi, A.
Rinderknecht, H.G.
Higginson, D.P.
Ryutov, D.D.
Bruulsema, C.
Drake, R.P.
Funk, S.
Glenzer, S.
Date Issued
August 2019
Journal
Nature Physics
Publisher
Nature
Abstract
Astrophysical collisionless shocks are among the most powerful particle accelerators in the Universe. Generated by violent interactions of supersonic plasma flows with the interstellar medium, supernova remnant shocks are observed to amplify magnetic fields and accelerate electrons and protons to highly relativistic speeds. In the well-established model of diffusive shock acceleration, relativistic particles are accelerated by repeated shock crossings. However, this requires a separate mechanism that pre-accelerates particles to enable shock crossing. This is known as the ‘injection problem’, which is particularly relevant for electrons, and remains one of the most important puzzles in shock acceleration6. In most astrophysical shocks, the details of the shock structure cannot be directly resolved, making it challenging to identify the injection mechanism. Here we report results from laser-driven plasma flow experiments, and related simulations, that probe the formation of turbulent collisionless shocks in conditions relevant to young supernova remnants. We show that electrons can be effectively accelerated in a first-order Fermi process by small-scale turbulence produced within the shock transition to relativistic non-thermal energies, helping overcome the injection problem. Our observations provide new insight into electron injection at shocks and open the way for controlled laboratory studies of the physics underlying cosmic accelerators.
Description
Submitted for publication in Nature Physics
MIT Department
Massachusetts Institute of Technology. Plasma Science and Fusion Center
Persistent DSpace Link
DOI of Published Version
https://doi.org/10.1038/s41567-020-0919-4
