Laser-Plasma Accelerator Workshop 2019

Impact of ultrafast laser generated Weibel magnetic fields on propagation dynamics of relativistic electron bunches

06.05.2019, 17:30

15m

Main Hall (MedILS)

Oral Contribution Diagnostics

Sprecher

O. Kononenko (LOA, ENSTA ParisTech, CNRS, Ecole Polytechnique, Institut Polytechnique de Paris)

Beschreibung

During laser solid target interactions, the onset of Weibel instability can generate super strong magnetic field structures (up to several $kT$) on the surface and within the bulk of the solid targets. Weibel magnetic fields can be used to understand several physical events in astrophysics [1] as well as impact laser driven inertial confinement fusion process [2] and gamma-ray generation experiments [3].
Here we report on the measurements of integrated Weibel magnetic fields at femtosecond time scale by using relativistic electron bunches from laser wakefield accelerators (LWFA) to probe the Weibel instability driven by the interaction between ultrashort ($30$ $fs$) intense ($I_0>{10}^{18}W/c{m}^2$) laser pulses and thin solid targets.
Experiments on hybrid Plasma Wakefield Acceleration, in which LWFA-generated electron beams are used to drive wakefield in another plasma target [4], demonstrated that the impact of such a strong magnetic field on a relativistic electron bunch can cause significant beam quality degradation, which complicates its further transportation and utilisation. We will present experimental and simulation results showing integrated B-field of few $kT\cdot m$ generated at the surface and in the bulk of the solid target within a depth of a few microns. The results show that the Weibel instability at femtosecond time scale can be explored with a convenient and simple method based on laser wakefield acceleration.

[1] A. Marcowith et al., Rep. Prog. Phys.79, 046901 (2016)
[2] J. S. Ross et al., Phys. Rev. Lett. 118, 185003 (2017)
[3] A. Benedetti et al., Nature Photonics 12, 319 (2018)
[4] M. F. Gilljohann et al., accepted to Phys. Rev. X (2019)