Post-doc in numerical study of flying focus for laser-wakefield acceleration. (M/F)

Job Description

Missions

Laser-plasma accelerators (LPAs) are a compact alternative to conventional accelerators and can generate ultra-relativistic electron beams over centimeter-scale distances thanks to extreme accelerating fields ( over 100 GV/m). A key limitation for beam energy is the dephasing between accelerated electrons and the plasma wake: electrons eventually outrun the accelerating phase, which caps the effective acceleration length and final energy. We explore a dephasing-free concept based on superluminal laser pulses, where the focal point can be made to propagate through the plasma at an arbitrarily controlled velocity, including faster than the speed of light in vacuum. This is achieved by combining an axiparabola, which focuses each annular portion of the near-field at a different longitudinal position, with a controlled radial delay introduced via spatiotemporal couplings (STC). Additionally, flying focus relies on a one-to-one mapping between the radial position on the optic and the longitudinal position along the focal line, so that each slice of the line can in principle be shaped independently thus opening the door to controlling not just group velocity but the pulse's full set of parameters as it propagates.
selected candidate will lead the numerical study of flying-focus laser pulses for laser wakefield acceleration, in close collaboration with the experimental programs on 100's TW-class and petawatt lasers. The work will focus on simulating flying-focus pulse propagation and its interaction with the plasma during acceleration using particle-in-cell (PIC) simulations, with particular attention to the ultrashort, sub-10 fs regime. Another key research direction will be to explore spatio-temporal configurations to tailor focal-line parameters such as position, duration or intensity so as to enhance electron injection, acceleration, or X-ray generation.

Activity

- Development and implementation of numerical simulations of flying-focus pulse propagation and its interaction with the plasma (Particle-in-Cell codes and optical propagation).
- Exploration of spatio-temporal configurations to optimize electron injection, acceleration, and X-ray generation.
- Analysis and interpretation of simulation results, in connection with the project's experimental campaigns.
- Development of analytical models to describe the laser-plasma interaction.
- Interaction with the experimental teams to help guide the campaigns and compare simulations with measurements.
- Scientific communication: writing scientific articles and participating in conferences.

Your Profil

Skills

- PhD in Physics with strong interest for plasma simulations.
- Prior experience with laser-plasma simulation, especially with Particle-in-cell codes.
- Expertise in one of the followings: laser-plasma accelerators, high-intensity lasers, laser-plasma interaction, optics.
- Ability to work in team, coordinate with PhD students.
- Good oral and written communication skills in order to write scientific articles and present results in international conferences.

Your Work Environment

The Laboratoire d'Optique Appliquée (LOA) is a joint research unit of CNRS/École Polytechnique/ENSTA Paris, located on the École Polytechnique campus in Palaiseau. A pioneer in laser-matter interaction and plasma physics for over 30 years, the laboratory's research covers a broad range of topics in ultrafast science, including the development of ultra-intense femtosecond laser systems, the physics of laser filamentation in air, and the realization of compact sources of radiation and energetic particles for academic, societal, and industrial applications. The selected candidate will join the Ultrafast Sources of Particles and X-rays (UPX) group. The position falls within a sector subject to the protection of scientific and technical potential (PPST) and therefore requires, in accordance with regulations, that your arrival be authorized by the competent authority of the MESR.

Compensation and benefits

Compensation

Between 3131€ et 4341€ gross per month depending on experience.

Annual leave and RTT

44 jours

Remote Working practice and compensation

Pratique et indemnisation du TT

Transport

Prise en charge à 75% du coût et forfait mobilité durable jusqu’à 300€

About the offer

About the CNRS

The CNRS is a major player in fundamental research on a global scale. The CNRS is the only French organization active in all scientific fields. Its unique position as a multi-specialist allows it to bring together different disciplines to address the most important challenges of the contemporary world, in connection with the actors of change.

CNRS

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