Abstract
Simultaneous self-focusing and compression of ultrashort weakly-relativistic Laguerre-Gaussian laser pulses in dense plasma is investigated theoretically and numerically. A simple theoretical model is developed and used to identify parameter regimes of interest, and then three-dimensional particle-in-cell simulations are carried out to examine the physics in detail. Rapid self-focusing and compression are observed, leading to pulse collapse even for laser pulse energy at the ten millijoule level. Long-lived ring-shaped post-soliton structures are left at the location of the first collapse, and the residual laser energy is scattered into the plasma. Filamentation and re-focusing occur beyond this point, the structure of which depends on the beam parameters but is observed to be only weakly dependent upon the mode of the laser. Circularly-polarised light is found to produce particulary symmetric plasma density structures. In all cases, bursts of MeV electrons with thermal-like spectra are observed at points of collapse.
Original language | English |
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Article number | 035002 |
Number of pages | 11 |
Journal | Journal of Physics Communications |
Volume | 7 |
Issue number | 3 |
Early online date | 24 Feb 2023 |
DOIs | |
Publication status | Published - 7 Mar 2023 |
Keywords
- Laguerre-Gaussian laser beams
- particle-in-cell simulations
- beam parameter