The propagation of multiple ultraintense femtosecond lasers in underdense plasmas is investigated theoretically and numerically. We find that the energy merging effect between two in-phase seed lasers can be improved by using two obliquely incident guiding lasers whose initial phase is $\pi$ and $\pi /2$ ahead of the seed laser. Particle-in-cell simulations show that due to the repuls... https://xstolqsd8l49r.nizarblog.com/35079800/effects-of-beta-alanine-supplementation-on-body-composition-a-grade-assessed-systematic-review-and-meta-analysis