a) Example of 10 spectra of angularly resolved electrons obtained during a series of 14 shots.
b) Two examples of angularly integrated spectra corresponding to the spectra marked with blue and green lines in (a).
Credit: Cédric Thaury.
Laser-plasma accelerators deploy extremely strong electric fields: 1000 times larger than those produced by conventional accelerators. They use very powerful pulsed femtosecond lasers that produce a plasma (electrons, ions) ionizing the subject matter (Matter is the substance that forms any body that has a tangible reality. It is …) and that generate fields by accelerating electrons.
To obtain a good quality, high-energy electron beam, two conditions must be met: pulse guidance laser (A laser is a device that emits light (electromagnetic radiation) …) in order to accelerate the electrons as far as possible, and the control (The word control can have several meanings. It can be used as a synonym for exam, of …) injection, that is, the place where the electron beam originates, in order to have the most monokinetic beam possible. Although these conditions had been obtained separately for more than 15 years, they had never been achieved simultaneously before.
When putting point (graphics) a fully optical guide method for low densities of gas (A gas is a set of atoms or molecules very weakly attached and …) adapted tolaser-plasma acceleration (Laser-plasma acceleration is a research topic aimed at developing …) and associating it with an electron injection for shock (As soon as two entities interact violently, we say there is a clash, if it is …)researchers from the Laboratory of Applied Optics (LOA, CNRS (The National Center for Scientific Research, better known by its acronym CNRS, is the largest …) / Ecole polytechnique / ENSTA) met both conditions and produced 1.1 GeV electron beams with unprecedented efficiency. This result eliminates an essential blockage that should significantly increase the performance of laser-plasma accelerators. These results are published in the journal Light science and applications.
To obtain these results, the scientists produced a fully optical plasma waveguide, that is, using a low-energy laser pre-pulse and focusing it on a gas beam using a new type of “optics.” developed (In geometry, the evolution of a flat curve is the geographical location of its centers of …) by experience. This pre-pulse generates a plasma channel from which density (The density or relative density of a body is the relationship between its density and the …) decreases towards the optical axis: then the main pulse is guided as in a fiber optic (An optical fiber is a very thin glass or plastic wire that has the property of …) with index gradient. This guide increases the distance over which the intense laser accelerates the electrons and so the final energy is multiplied by 3. To obtain a beam from which dispersion (Dispersion, in wave mechanics, is the phenomenon that affects a wave in a …) in energy is low, it is necessary that the electrons accelerated by the laser pulse come from a well-defined region of the gas. To ensure this control of electron injection, the electronic density of the plasma was modeled producing a shock in the gas, locally generating a strong density gradient that particularizes the region of the electrons that will accelerate. This results in a good energy resolution (figure). The next step is to improve the aiming of the laser at the gas, the accuracy of which influences the intensity of the electron beam.
An important advantage of the fully optical guide, the first of which demonstration (In mathematics, a demonstration allows to establish a proposition from …) was held here for theacceleration (Acceleration usually refers to an increase in speed; in physics, …) plasma, is to greatly limit the damage related to the Powerful (The word power is used in several fields with a particular meaning 🙂 of the laser, thus allowing arbitrarily high energies and repetition rates. Therefore, this approach opens up promising prospects for the community. A country (The field, also called rural environment, designates all cultivated areas …) of experiences in the Infrastructure of research (Scientific research first designates all the actions carried out with the aim of …) (IR) Apollo (Apollo (Ancient Greek? Π? Λλων / Apóllôn, Latin Apollo) is the god …)whose laser is 10 times more powerful will aim to triple the energy of the electron beam obtained. A particularly interesting final perspective is to use Apollo for very fundamental studies such as those related to thequantum electrodynamics (Relativistic quantum electrodynamics is a physical theory that aims to reconcile …).
Controlled acceleration of GeV electron beams in a fully optical plasma waveguide.
Kosta Oubrerie, Adrien Leblanc, Olena Kononenko, Ronan Lahaye, Igor A. Andriyash, Julien Gautier, Jean-Philippe Goddet, Lorenzo Martelli, Amar Tafzi, Kim Ta Phuoc, Slava Smartsev & Cédric Thaury, Light: science and applicationspublished on June 14, 2022.
TWO: 10.1038 / s41377-022-00862-0.
Open file HAL i arXiv.
– Cédric Thaury – CNRS Researcher, Laboratory of Applied Optics – cedric.thaury at ensta.fr
– Communication (Communication affects both people (intrapsychic, interpersonal communication, etc.) INP – inp.com at cnrs.fr
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