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Reference : UMR5107-SOPHEU0-027
Workplace : TALENCE
Date of publication : Wednesday, February 17, 2021
Type of Contract : FTC Scientist
Contract Period : 12 months
Expected date of employment : 1 April 2021
Proportion of work : Full time
Remuneration : Between 2,648 and 3,768 € gross monthly according to experience
Desired level of education : PhD
Experience required : Indifferent
Laser ion acceleration is an attractive way to realize compact and intense ion sources for many promising applications, including proton therapy, proton radiography and inertial confinement fusion. Potential developments depend on the ability of laser installations to deliver reproducible ion beams at high repetition rate. In this context, the use of cryogenic hydrogen ribbons or gas-jet targets are promising avenues. When a near-critical target, i.e. at a density close to the limit density above which the laser is reflected, is irradiated by a laser pulse, under certain conditions an electrostatic shock can be launched in the target. Such a shock can reflect the ions upstream and produce ion beams with monoenergetic peaks of a few MeV. Indeed, the maximum energy of the ions is strongly limited by the losses of laser energy due to nonlinear phenomena (self-focusing and filamentation) which occur in the density ramp of dense gas jets, but could be greatly increased using cryogenic targets. Through numerical simulations with the SMILEI Particle In Cell (PIC) code, the postdoc will begin to analyze and optimize the physical processes of ion acceleration in cryogenic targets and compare with near-critical density gas-jet targets. The first PIC simulations will be carried out in 1D and 2D plane geometries. On the basis of these simulations, the design of a future experiment could be proposed.
The role of the postdoc will be to analytically and numerically model the production of collimated energetic ion sources. To this end, the postdoc will have to perform PIC simulations, using the numerical codes available at CELIA. He / she will be in charge of the choice of the targets to be studied (cryogenic targets, dense gas jets ...), and of obtaining scaling laws allowing to predict the characteristics of the energetic ions produced according to the parameters of the laser pulses used, and to the target parameters. He / she will also have to develop codes or scripts dedicated to the optimization of numerical diagnostics.
• Hold a doctorate or equivalent level of skills and experience in the scientific field of plasma physics (essential).
• Have a solid training in plasma physics, giving evidence of the ability to conduct original research and produce scientific papers (essential).
• Experience in the use and interpretation of plasma simulations (PIC, hydro-radiative, MHD) (essential).
• Experience in developing plasma simulation codes (PIC, hydro-radiative, MHD) (desirable).
• Experience in performing laboratory experiments with plasmas (desirable).
• Experience in the design and development of targets for laser-plasma experiments (desirable).
This position will require a lot of teamwork and interdisciplinary research. The postdoc will interact on a daily basis with other researchers at CELIA (experimentalists, theoreticians and numerical physicists), as well as with external collaborators. The postdoc is expected to participate in the production of independent and original research, to deliver articles for publication in peer-reviewed journals and to participate in the animation of the research group.
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