STUDY OF ELECTROMAGNETIC RADIATION FROM ELECTROSTATIC' SOLITARY WAVES IN SPACE PLASMAS

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We have developed a new method to realize an efficient absorbing boundary for ele'ctro hagnetic particle simulations with a minimal size of the damping region. We have also developed a new algorithm of the charge conservation method for current density calculation, which substantially reduced the computation. We have demonstrated existence of higher harmonics of Langmuir waves enhanced by an electron beam by a newly developed Vlasov code. In an open system with the absorbing boundaries, we traced a long time and long distance evolution of the electron beam instability, showing formation of electrostatic solitary waves and their coupling with oblique whistler waves and lower, hybrid waves, which are localized in the region close to the electron beam generation region. In the two dimensional system, we find the electrostatic solitary waves are accompanied by electromagnetic components due to the localized current driven by the ExB drift associated with the perpendicular electric field of two-dimensional electrostatic potentials. We found an electron beam formation through Buneman instability driven by an induced electric field in the boundary layers of the magnetosphere. The structure and characteristics of electrostatic waves were analyzed theoretically, and the analysis was also extended to a three dimensional model. We obtained the necessary conditions for existence of isolated three-dimensional potentials.