Relativistic attosecond electron pulses by laser wakefield acceleration

Sammanfattning: The search for cheaper and more compact accelerators has led to the development of laser-driven plasma-based accelerators. In comparison to conventional particle accelerators, the plasma-based accelerator is inherently insensitive to the breakdown of the acceleration structure and therefore greater accelerating fields can be obtained. One such setup, which is used to accelerate electrons, is the laser wakefield accelerator. Behind the laser, an electric field gradient of the order of hundreds GV/m can be obtained as the intense laser pulse propagates through the plasma, and electrons submitted to this field can be accelerated to several MeV over just few millimeters. During 2020, the Division of Atomic Physics at Lund University will purchase a new laser system, and in comparison to the old system, the new laser system has a shorter pulse duration, lower energy, and higher repetition rate. Through particle in cell simulations, it has in this thesis been shown that attosecond electron pulses can be achieved with the parameters of the new laser system. The duration of the electron pulses is tuned by modulating the plasma density. The energy of the these short electron pulses are of the order of tens of MeV. However, for the specified plasma density, it is more beneficial to drive the wakefield by a laser with four times the energy than the system the upgraded laser system the Division plans to purchase. The energy spectrum of the accelerated electrons at this laser energy proved to be more peaked, and the electrons could be accelerated over a longer distance than if the energy of the upgraded laser system were utilized.