Theoretical Research on Relativistic Interaction of Ultra-Intense Laser Light with High Density Plasmas

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This work consists of analytical and computational researches both being conducted by active international collaborations.Analytical Research : A general theory was constructed on the one-dimensional stationary propagation of a high intensity circularly-polarized electromagnetic wave by relativistic effects in over-critical density plasmas. Propagation characteristics of a short pulse laser light is analysed using a kinetic equation for the spectral function of electromagnetic waves and general dispersion relation for electromagnetic waves is derived with full account of relativistic effects. A non-potential ponderomotive force is derived and its generation of low frequency magnetic fields and the resulting electron eddy and plasma jet formation are demonstrated.Computational Research : 2-dimensional simulation for relativistic interaction of laser light with nonuniform plasmas is conducted and production of MeV energy plasma particles is confirmed. Electromagnetic waves trapped in a local density cavity is emitted as bursts and stochastic acceleration of electrons due to resonance with the light field is demonstrqated. 2- and 3-dimensional simulations are carried out on the relativistic interaction of ultra-high intensity laser pulse with slowly nonuniform plasma. Laser propagation channels are produced by self-focusing or filamentation and electron acceleration, various instabilities, current sheets formation, generation of quasi-static magnetic fields, their splitting into filaments and their merging, anomalous transport of fast electron current across magnetic fields and resulting current neutralization with the return current are demonstrated. Anomalous heating of the background plasma by an anomalous resistivity is also disclosed.