Search

Abstract: Laser wakefield acceleration experiments with the 150fs Texas Petawatt laser will be carried out in the unique regime with the shortest pulse duration among available petawatt facilities. Simulations via the time-averaged, fully relativistic, quasi-static 3D axi-symmetric particle-in-cell (PIC) code WAKE show that combination of nonlinear plasma wave focusing, relativistic self-focusing, and nonlinear temporal compression guide a 1.33 PW pulse over 10cm of uniform plasmas. Self-guided TPW pulse has intensity above 1019 W/cm2 and drives the laser wakefield in the blowout regime in the plasma density range n 0 >2×1017 cm−3. Both test-particle (WAKE) and full 3D PIC modelling (using recently developed quasi-cylindrical CALDER-Circ code) demonstrate robust electron self-injection in the first plasma wave bucket (“bubble”) during the periods of laser defocusing and bubble growth. Injection terminates as soon as the laser evolution stabilizes. As a result, quasi-monoenergetic acceleration of ∼1.3nC electron bunch to the 2.5–7GeV is expected in 10-cm long plasmas. [Copyright &y& Elsevier]

Abstract: We report on generation of relativistic electron beams in the wake of a relativistically intense laser pulse traversing a 1.7mm long atmospheric density helium gas jet. The plasma wake structure is recovered using a Frequency-Domain Holography (FDH) and Frequency-Domain Shadowgraphy (FDS). As the gas density changes, the accelerated electron beams show variations in cross-section area, divergence, total charge, and peak energy. FDH phase reconstruction shows discontinuities and large phase jumps due to plasma electrons blown out by the pump pulse, probe pulse refraction, and nonlinear propagation in plasma. However, FDS amplitude reconstruction shows bright spots that yield information about bubble formation and evolution. [Copyright &y& Elsevier]