The role of laser chirp in relativistic electron acceleration using multi-electron gas targetsThe role of laser chirp in relativistic electron acceleration using multi-electron gas targets Peer-Reviewed Journal Publication Δημοσίευση σε Περιοδικό με Κριτές 2025-07-292023enThe role of multi-10 TW chirped laser pulses interacting with N2 gas jet targets, as a test case for multi-electron targets, is experimentally examined. Complementary measurements using He gas jet targets, which are fully ionized well before the laser pulse peak, are also presented for comparison with the measurements for the multi-electron N2 targets. It is found that for both gases positively chirped laser pulses accelerate electrons more efficiently compared to the Fourier transform-limited and negatively chirped pulses. Furthermore, multi-electron targets offer additional electron injection mechanisms for efficient electron acceleration as a function of the chirp, due to the dynamic ionization of inner-shell electrons near the peak of the laser pulse. Finally, we show that the background plasma density value plays a critical role in the efficient acceleration of positively chirped pulses as well as in the tuning of the positive chirp value for maximizing the electron energy. We clearly observe that larger plasma density values require higher positive chirp values for efficient electron acceleration.A G acknowledges financial support by the Hellenic Foundation for Research and Innovation (HFRI) under the 3rd Call for HFRI PhD Fellowships (Fellowship Number: 5985). This work has been carried out within the framework of the EUROfusion Consortium, funded by the European Union via the Euratom Research and Training Programme (Grant Agreement No. 101052200–EUROfusion) and the Hellenic National Program of Controlled Thermonuclear Fusion. The involved teams have operated within the framework of the Enabling Research Project: ENR-IFE.01.CEA-02 ‘Advancing shock ignition for direct-drive inertial fusion’.http://creativecommons.org/licenses/by/4.0/Plasma Physics and Controlled Fusion654Grigoriadis_et_al_Plasma Phys. Control. Fusion_65(4)_2023.pdfChania [Greece]Library of TUC2025-07-29application/pdf1.3 MBfree Grigoriadis Anastasios Andrianaki Georgia Ανδριανακη Γεωργια Tatarakis, Michael, 19..- Benis Emmanouil Papadogiannis Nektarios IOP Publishing Laser wakefield acceleration (LWFA) Laser plasma interaction Chirped laser pulses