Dynamics of ultra-intense circularly polarized solitons under inhomogeneous plasmas

Abstract

The dynamics of the ultra-intense circularly polarized solitons under inhomogeneous plasmas are examined. The interaction is modeled by the Maxwell and relativistic hydrodynamic equations and is solved with fully implicit energy-conserving numerical scheme. It is shown that a propagating weak soliton can be decreased and reflected by increasing plasma background, which is consistent with the existing studies based on hypothesis of weak density response. However it is found that ultra-intense soliton is well trapped and kept still when encountering increasing background. Probably, this founding can be applied for trapping and amplifying high-intensity laser-fields.PACS numbers: 52.38. Kd, 41.75.Jv, 52.35.Mw, The interaction between lasers and plasmas has attracted much attention since the invention of chirped pulsed amplification technology, 1,2 which makes ultraintense laser with intensity (I 0 > 10 18 W/cm 2 ) applicable. Interaction between such intense lasers and plasmas exhibits a rich variety of interesting nonlinear phenomena. One such phenomenon, namely the dynamics of electromagnetic solitons, has drawn much attention analytically, numerically and experimentally.3-32 As nearly 30% ∼ 40% of the laser pulse energy can be transformed into solitons.3,4 This fairly high efficiency of electromagnetic energy transformation indicates that solitary waves can play an important role in the development of the interaction between the laser pulses and plasmas. In fact, many theoretical problems are still open even for onedimensional solitons, namely the properties of linearly polarized solitons 4 and the soliton dynamics in the presence of plasma inhomogeneity [22][23][24][25][26] . In reality, the background plasma density is always inhomogeneous, thus it is of great necessity to investigate the dynamics of solitons under inhomogeneous plasma background.Researches on the propagation of solitons under inhomogeneous background plasma have been conducted by various authors.22-26 The pioneering work in this field is on the theoretical studies of the Langmuir soliton through an inhomogeneous plasma. Their analytical conclusions have demonstrated the acceleration (deceleration) of solitons in the presence of decreasing (increasing) plasma background.22 However there is a obviously shortcoming in this work, the group velocity of the soliton is treated as an independent parama) Electronic mail: wudongphysics@gmail.com b) Electronic mail: zheng chunyang@iapcm.ac.cn c) Electronic mail: xthe@iapcm.ac.cn eter. In fact, the velocity, frequency and amplitude of the soliton are closely related, which is determined by an eigenvalue condition.27 Later on, the propagation of electromagnetic solitonic structures under inhomogeneous plasma has been investigated. 23,24 However, all these related researches have been limited to the hypothesis of weak density response.27 The weak density response theory can not deal with ultra-intense solitons accompanied with heavy plasma density cavitation. The dynamic behavior of solitons under rare bac...

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