Speaker
Thales Silva
Description
See the full Abstract at http://ocs.ciemat.es/EPS2018ABS/pdf/P4.2019.pdf
Anisotropic heating and magnetic field generation due to Raman
scattering in laser-plasma interaction
T. Silva1 , J. Vieira1 , M. Hoshino2 , R.A Fonseca1,3 , L. O. Silva1
1 GoLP/Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade de
Lisboa, 1049-001 Lisbon, Portugal
2 Departament of Earth and Planetary Science, University of Tokyo, 113-0033 Tokyo, Japan
3 DCTI/ISCTE Insituto Universitário de Lisboa, 1649-026 Lisbon, Portugal
The interaction of intense electromagnetic waves with plasmas is a rich research topic be-
cause of its importance in basic plasma science and in potential scientific and societal applica-
tions, ranging from advanced fusion devices to compact plasma based accelerators and radiation
sources. Magnetic fields play a crucial role in this context: they may stabilise hot electron cur-
rents against beam-break up instabilities, are vital to reproduce extreme astrophysical scenarios
in the laboratory, and make plasma-based radiation emission processes more efficient. There
are several processes that can lead to the generation and amplification of magnetic fields. Re-
cent experiments, for instance, demonstrated the generation large-scale [1] due to hot electron
currents in underdense plasmas, and determined the turbulent [2] dynamics of intense magnetic
fields in laser-solid interactions.
In general, magnetic field generation depends on the specific temperature distribution of hot
electrons. Thus, controlling how heating occurs is important to enhance magnetic field gen-
eration in laser-plasma interactions. In this work we explore a novel mechanism to drive the
Weibel instability in laser-plasma interactions by controlling the temperature of background
plasma electrons in each direction, independently. The scheme employs an intense laser pulse
propagating in an underdense plasma. Using two and three-dimensional particle-in-cell simula-
tions with the code OSIRIS [3], we show that the interaction is subject to Raman side-scattering.
We find that electron heating is stronger along the direction where the scattered plasma wave
phase velocity is lower due to Landau damping. Thus, our work shows that this setup creates an
angle-dependent temperature distribution capable of driving the Weibel instability. We discuss
the role of the laser polarisation in our findings.
References
[1] A. Flacco et al Nature Physics 11, 409 (2015).
[2] G. Chatterjee et al Nat. Comms. 8, 15970 (2017).
[3] R. Fonseca, et al., Lecture Notes in Computer Science 2331, 342 (2002)
