Skip to Main content Skip to Navigation
Theses

Modélisation de l'accélération d'électrons par des impulsions lasers relativistes de quelques cycles optiques sur des plasmas surdenses

Abstract : This theoretical and numerical thesis is devoted to electron acceleration from the interaction between a relativistic intensity laser pulse and an overdense plasma. This interaction is very sensitive to the density profile at the plasma front surface and two different regimes, which correspond to two distinct lines of research investigated in this thesis, can be considered.First, for sharp plasma-vacuum interfaces, the mechanisms responsible for electron emission are well understood. The electrons receive in particular a large energy gain from their interaction in vacuum with the reflected laser. We propose to optimize the acceleration by using radially polarized beams, which exhibit a strong longitudinal electric field that can directly accelerate electrons in the laser propagation direction. We show that overdense plasmas lead to more efficient acceleration than other existing methods for injecting electrons into a radially polarized pulse. This result was confirmed by recent experiments performed at CEA Saclay, in which electron acceleration in the longitudinal direction, leading to a decrease in the electron beam angular spread, is demonstrated.Secondly, for larger plasma gradient scale lengths, the interaction is not as well understood. We analyze recent experiments performed in this regime at LOA with few-cycle pulses and find that electrons are accelerated by a laser wakefield formed in the near-critical part of the plasma. This process can only be driven by few-cycle pulses, by virtue of the resonant condition, and is characterized by the rotation of the plasma waves induced by the density gradient.
Complete list of metadatas

Cited literature [332 references]  Display  Hide  Download

https://tel.archives-ouvertes.fr/tel-02489458
Contributor : Abes Star :  Contact
Submitted on : Monday, February 24, 2020 - 2:44:42 PM
Last modification on : Friday, October 23, 2020 - 4:52:30 PM

File

83142_ZAIM_2019_archivage.pdf
Version validated by the jury (STAR)

Identifiers

  • HAL Id : tel-02489458, version 1

Collections

Citation

Neïl Zaim. Modélisation de l'accélération d'électrons par des impulsions lasers relativistes de quelques cycles optiques sur des plasmas surdenses. Plasma Physics [physics.plasm-ph]. Université Paris Saclay (COmUE), 2019. English. ⟨NNT : 2019SACLX089⟩. ⟨tel-02489458⟩

Share

Metrics

Record views

151

Files downloads

149