High energy high stability laser wakefield electron acceleration with the J-KAREN-P laser

Laser wakefield acceleration (LWFA) has the advantage of ultrahigh acceleration gradient allowing GeV energy gain within centimeter acceleration structure. However, for application concerns, the stability of electron bunches from LWFA still need to be improved. In 2018, we utilized the ionization-injection regime and generated electron beams with charges at nC level in a single peak with the J-KAREN-P laser facility. Yet, the stability was not satisfactory. In 2019, by introducing the density transition regime with mixture gas, we observed relatively stable electron beams with energies of several hundred MeV. In addition, by using a two-gas-jet set-up, we generated electrons with energies up to 2 GeV. Beam driven plasma wakefield was considered to be responsible for the multi-GeV electron generation in the experiment.日本物理学会 第75回年次大