High-energy particles and relativistic sources in astrophysics


High-energy particles and relativistic sources in astrophysics
Where do cosmic rays, neutrinos and high-energy photons come from? How is
radiation emitted from black hole environments, blazars, gamma-ray bursts and other
relativistic sources? What process gives rise to the electromagnetic counterparts of
gravitational wave events? All these questions shape the rapidly-developing fields of
high-energy astrophysics and multi-messenger astrophysics. At the heart of these
questions lies a same theoretical question: the nature of the process that turns these
sources into powerful particle accelerators. The aim of this PhD is to advance our
understanding of the mechanisms by which very high-energy particles are
accelerated in the turbulent, relativistic and magnetized flows of powerful
astrophysical sources, in particular gamma-ray bursts, blazars and pulsar nebulae.
The acceleration process relies on the interaction between these charged particles
and the electromagnetic fields carried by the surrounding plasmas. The physics
involved is rich and it involves non-linear and multi-scale plasma processes in
extreme conditions: relativistic, strongly magnetized flows, possibly composed of
electron-positron pairs etc. This research is mostly theoretical, and it relies heavily on
high-performance numerical computation, using the particle-in-cell (PIC) method,
which allows to resolve in a consistent manner the non-linear relationship between
the electromagnetic fields and the accelerated particles.
This thesis proposes to study the physics of high-energy particle acceleration in
relativistic and magnetized turbulent flows, as encountered in powerful sources. This
work will be carried out in conjunction with massively parallel PIC numerical
simulations and advanced analytical models. The PhD candidate will also work on
phenomenological applications of these studies to multi-messenger astrophysics.
The thesis will be carried out under the supervision of Martin Lemoine in the
« Astroparticule & Cosmologie » laboratory of Université Paris-Cité, in co-direction
with Laurent Gremillet (CEA/DAM/DIF).
Martin Lemoine
Astroparticule & Cosmologie
CNRS – Université Paris Cité
75013 Paris
email: martin.lemoine2atgmail.com
Laurent Gremillet
91680 Bruyères-le-Châtel
email : laurent.gremilletatcea.fr


Martin Lemoine






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