Electron acceleration by wave turbulence in a magnetized plasma
Astrophysical shocks are commonly revealed by the non-thermal emission of energetic electrons accelerated in situ 1 – 3 . Strong shocks are expected to accelerate particles to very high energies 4 – 6 ; however, they require a source of particles with velocities fast enough to permit multiple shock...
Saved in:
Published in | Nature physics Vol. 14; no. 5; pp. 475 - 479 |
---|---|
Main Authors | , , , , , , , , , , , , , , , , , , , , , , , , , , |
Format | Journal Article |
Language | English |
Published |
London
Nature Publishing Group UK
01.05.2018
Nature Publishing Group Nature Publishing Group (NPG) |
Subjects | |
Online Access | Get full text |
Cover
Loading…
Summary: | Astrophysical shocks are commonly revealed by the non-thermal emission of energetic electrons accelerated in situ
1
–
3
. Strong shocks are expected to accelerate particles to very high energies
4
–
6
; however, they require a source of particles with velocities fast enough to permit multiple shock crossings. While the resulting diffusive shock acceleration
4
process can account for observations, the kinetic physics regulating the continuous injection of non-thermal particles is not well understood. Indeed, this injection problem is particularly acute for electrons, which rely on high-frequency plasma fluctuations to raise them above the thermal pool
7
,
8
. Here we show, using laboratory laser-produced shock experiments, that, in the presence of a strong magnetic field, significant electron pre-heating is achieved. We demonstrate that the key mechanism in producing these energetic electrons is through the generation of lower-hybrid turbulence via shock-reflected ions. Our experimental results are analogous to many astrophysical systems, including the interaction of a comet with the solar wind
9
, a setting where electron acceleration via lower-hybrid waves is possible.
Electrons can be accelerated by astrophysical shocks if they are sufficiently fast to start with. As laboratory laser-produced shock experiments reveal, this can be achieved by lower-hybrid waves generated by a shock-reflected ion instability. |
---|---|
Bibliography: | USDOE Office of Science (SC) SC0016566 |
ISSN: | 1745-2473 1745-2481 |
DOI: | 10.1038/s41567-018-0059-2 |