Your application must include a letter from your Ph.D. supervisor, a letter from your future lab director, a detailed CV including university education and work experience, a list of publications, a 2-page description of the work undertaken during the course of your PhD as well as a few recommendation letters. Please combine all of these documents in a single file to ease the review process.

For more Information, contact : Directeur de Recherche - Severine.BOYER@mines-paristech.fr

Submit the complete application online (Apply) before March 31th, 2022 Midnight Paris time

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A national program is piloted by the CNES Launcher Direction for the preparation of the future on Spatial Transport (1.). Aim is to apprehend the stakes of tomorrow and future breaks (reusable vehicle).

In close cooperation with CNRS teams, a bunch of complementary scientific expertise has been implemented to investigate the Laser Ablation Propulsion (LAP): the feasibility of creating a pushing force by laser on an ablative target by creating locally at the target surface a plasma ejected at high speed is demonstrated.

The coupling coefficient Cm was measured using the concept of ballistic pendulum especially redesigned according to the level of laser energies and coupled with a Photonic Doppler Velocimetry system and angle measurement using laser deflection. Different materials were tested: aluminum (Al), polyoxymethylene (POM), hybrid POM-Al.

Preliminary planned works started in France from 2017 to 2018 with the first 'LAP-single pulse' campaigns, jointly with Ecole Polytechnique, CNRS, CEA, Photonic Associates (US). ELFIE beam was used, LAP (1053nm, 400fs & 80ps) (2.,3.).

We recently extended the works to further go to the preliminary design of a laser-powered microlighter. It feeds into a European Union tender response to HILASE, the laser center of excellence in Czech Republic. PERLA-B beam was used. The campaign involved ENSTA-Bretagne, PPRIME-ENSMA, Pardubice Univ. (CZ) (4.) with the guidance of C.Phipps (US). LAP implies repeated ablation on the same spot (infrared laser at 1 kHz, 1030nm, 6ps), which is a complex phenomenon quite different from single pulse. Several cases were considered by changing number of pulses at constant energy per pulse and energy per pulse at a constant number of pulses. Numerical calculations for modeling the laser-material interaction with ESTHER software from CEA were also tested. A summary of the results are found in the report of G.Tahan (publications in progress (5.,6.)).

Further advanced data are needed to eliminate existing uncertainties I. primarily in thermal coupling and mass loss on the way to achieving space LAP, and II. to get better understanding of energy vs. efficiency. This collection of smart-data will make it possible to define tracks, and assist with the preliminary design proposal for a laser-powered micro launcher.

Aim is to advance the several concepts of LAP demonstrators. The project will be in collaboration with Photonic Associates (US). Europeans collaborative works are planned (HILASE, DLR (Germany)).

It is advisable to propose several concepts, in particular: I. materials & designs of systems: to identify optimum laser-materials interactions answer, II. demonstrators under laser beam: to reproduce different conditions of Space situations (levitation to measure the propulsion length ; air cushion table for stability test of vehicle (Scharring 10.117/1.OE.56.1.011007) ; linear rail support with adjustable compensation force by changing rail angle), III. calculation: to identify news advances in thermal effect induced by laser-materials interaction according to (I.), and for the aerodynamic aspects to see which form of the demonstrator will be the most stable/the most controllable according to (I. & II.).

The post-doc would treat:

• Extend the definition of a target for the demonstrator: what power, what mission?

• Laser beams: we identified laser technologies with HILASE center (PERLA-C, BIVOJ) with access to the high power laser labs. (ultrashort pulses, 1030 & 515nm, repetitive LAP) (7.) ; in preparation to access to the large scale laser facilities, we would keep on carrying out proofs of concept on smaller scale laser available at ENSTA-Bretagne (1064 & 532nm, repetition rate up to 10Hz)

• Laser ablation vessel definition: size, shape, steering strategy. An optimal composition for the ablative material still needs to be tested

Materials: metals with relatively large thermal conductivity (Al, tantalum,titanium), ceramic (TiO2) with low thermal conductivity

• Thermal aspects: with the contribution of DLR (S.Scharring)

• Aerodynamic aspects: what lift, drag, stability for the ship? This point remains still to be better studied

• Organizational aspects: The post-doc should draft schemes for a possible evolution of the topic towards a European program on the basis of the already established collaborations around HILASE facility.

osition: Post-doctoral, 2 years

Post-doctoral candidate to be recruted

Profil, PhD in:

space, laser physics, plasma physics, materials science, mechanical engineering

Experimental and numerical fields motivations