Laser-assisted propagation of a relativistic electron bunch in air

Autor: D S Hills, T. Goffrey, R M Deas, Alexander Robinson, J R Wilkinson, Stephen Morris, J N Kirk, Keith Bennett, Raoul Trines, Tony Arber
Rok vydání: 2021
Předmět:
Zdroj: Plasma Physics and Controlled Fusion. 63:084009
ISSN: 1361-6587
0741-3335
DOI: 10.1088/1361-6587/ac0b9d
Popis: This paper assesses the feasibility of using kilo-joule class laser systems to pre-ionise an air column enhancing the propagation of relativistic electron beams. In a vacuum a charged beam will always diverge. In a plasma it may focus depending on the degree of beam charge and current neutralisation. Beams diverge due to scattering, but this paper highlights a parameter regime where plasma focusing in a pre-formed plasma may allow propagation of ∼10 GeV electron beams over a distance ∼10 m. Central to this theory is the degree to which the background plasma acts to charge or current neutralise the electron beam. These effects are quantified in a reduced 2D model using relativistic kinetic plasma simulations. These demonstrate that charge neutralisation is sufficiently high, and current neutralisation sufficiently low, that the proposed scheme is viable. The key problem identified in this paper is the difficulty in forming a suitable ionised channel. The primary laser energy loss mechanism for the parameters chosen is through inverse bremsstrahlung, not air ionisation, and possible ways to mitigate these losses are discussed.
Databáze: OpenAIRE