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Reference : UMR5274-CLADUP-011
Workplace : GRENOBLE
Date of publication : Saturday, May 01, 2021
Scientific Responsible name : Benoit Cerutti
Type of Contract : PhD Student contract / Thesis offer
Contract Period : 36 months
Start date of the thesis : 1 September 2021
Proportion of work : Full time
Remuneration : 2 135,00 € gross monthly
Description of the thesis topic
The main objective of this thesis is to develop a force-free magnetohydrodynamic (MHD) method, computationally cheaper and valid in
most of the magnetosphere, coupled with the PIC approach within the same numerical framework. This hybrid numerical scheme optimize the use of the PIC method only where ideal MHD does not apply and where particle acceleration occurs, therefore allowing one to perform more realistic multi-scale relativistic plasma astrophysics. The first astrophysical application for validation will focus on the magnetosphere of an aligned pulsar in a flat spacetime. The code will then be generalized to a Kerr metric using the 3+1 formulation of general relativity for an application to a spinning black hole magnetosphere.
This work will be carried out in the context of the SPAWN ERC project funded by Europe, which aims at better understanding the origin of particle acceleration in the closest vicinity of supermassive black holes. The thesis will be supervised by Benoît Cerutti, CNRS researcher at IPAG, expert in relativistic magnetospheres and creator of the Zeltron code.
IPAG is a Mixed Research Unit of 150 people under the supervision of CNRS and Grenoble Alpes University. IPAG will provide all the necessary resources (office, workstation, scientific environment) to carry out this work within the dynamic SPAWN team.
Neutron stars and black holes are the central engine of many high-energy astrophysical phenomena, such as pulsars, active galactic nuclei and gamma-ray bursts. Several observational and theoretical clues suggest that particle acceleration is very efficient in the near and magnetized environment of these compact stars (the magnetosphere). The first image of the shadow of the supermassive black hole M87* is one of the most beautiful recent example. Relativistic magnetospheres provide a unique environment to probe physics pushed into the most extreme regimes, which
are currently not reproducible in laboratory and where plasma physics, quantum electrodynamics and general relativity meet.
The use of high-performance computing plasma simulations can now reproduce these physical conditions with an unprecedented level of details.
The research team at IPAG has developed the particle-in-cell (PIC) code Zeltron, in order to model any relativistic plasma at a kinetic scale. The code has been recently upgraded with radiative and general relativistic effects. The PIC approach has the advantage to capture all plasma effects ab-initio, but it has the disadvantage of
being computationally expansive, hence limiting the dynamical range of physical parameters accessible by the simulation.
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