title: Collision of counterpropagating laser-excited wake bubbles.
abstract: The collision of wake bubbles behind two counterpropagating laser pulses in rarefied plasma is investigated using particle-in-cell simulation. Special attention is paid to the highly nonlinear dynamics of the electrons in the interaction region. It is found that, as the two bubbles approach each other and collide, the electrons in the interaction region first oscillate in a periodic fashion, forming a quasistationary dense electron density ripple with fairly regular spatial structure. At longer times, the electron motion becomes chaotic, and the density grating is gradually smeared. The electrons escape in the transverse direction, and eventually the two bubbles merge to form a single one. The transition of the electron motion from regular to chaotic is confirmed by analytical modeling using test electrons moving in counterpropagating planar electromagnetic waves. The findings shed light on the dynamics of wake-bubble collisions and the complex behavior induced by multiple laser pulses in plasmas.
authors.affiliation: Department of Physics, Zhejiang University, Hangzhou 310027, China and School of Physics and Information Technology, Shaanxi Normal University, Xi'an 710062, China.
authors.forename: Z G
authors.initials: ZG
authors.lastname: Deng
authors.affiliation: Department of Physics, Zhejiang University, Hangzhou 310027, China and Institute for Fusion Theory and Simulation, Zhejiang University, Hangzhou 310027, China.
authors.forename: L
authors.initials: L
authors.lastname: Yang
authors.affiliation: Institute of Applied Physics and Computational Mathematics, Beijing 100094, China.
authors.forename: C T
authors.initials: CT
authors.lastname: Zhou
authors.affiliation: Institute for Fusion Theory and Simulation, Zhejiang University, Hangzhou 310027, China.
authors.forename: M Y
authors.initials: MY
authors.lastname: Yu
authors.affiliation: Department of Physics, Zhejiang University, Hangzhou 310027, China.
authors.forename: H P
authors.initials: HP
authors.lastname: Ying
authors.affiliation: Department of Physics, Zhejiang University, Hangzhou 310027, China and School of Physics and Information Technology, Shaanxi Normal University, Xi'an 710062, China.
authors.forename: X G
authors.initials: XG
authors.lastname: Wang
mesh_terms: D003198:Computer Simulation; D007834:Lasers; D008956:Models, Chemical; D009991:Oscillometry / Q000379:methods; D058626:Plasma Gases / Q000737:chemistry* / Q000528:radiation effects*; D011829:Radiation Dosage; D012212:Rheology / Q000379:methods*
chemical_list: D058626:Plasma Gases