HR: 0800h
AN: SH31A-1176    [Abstracts]
TI: Quasilinear Simulation of Harmonic Electromagnetic Emission via Beam-driven Langmuir Waves in the Solar Wind
AU: Li, B
EM: boli@physics.usyd.edu.au
AF: School of Physics, University of Sydney, Parammatta Rd, Camperdown, Sydney, NSW 2006 Australia
AU: Willes, A
AF: School of Physics, University of Sydney, Parammatta Rd, Camperdown, Sydney, NSW 2006 Australia
AU: Robinson, P
AF: School of Physics, University of Sydney, Parammatta Rd, Camperdown, Sydney, NSW 2006 Australia
AU: * Cairns, I
AF: School of Physics, University of Sydney, Parammatta Rd, Camperdown, Sydney, NSW 2006 Australia
AB: The linked nonlinear processes of electrostatic Langmuir decay and electromagnetic emission are important for type III solar radio emissions, and other emissions in space plasmas. For instance, to generate the observed levels of emission at the second harmonic plasma frequency in most type III bursts, it is usual to invoke nonlinear three-wave processes where beam-driven Langmuir waves coalescence with Langmuir products from Langmuir electrostatic decay. In this work, second harmonic emission is studied using quasilinear theory for situations where the Langmuir waves are driven by an electron beam. An approximate method for studying wave decay and emission in three spatial dimensions is developed, based on the Langmuir and ion-acoustic wave dynamics in one spatial dimension. The numerical results are explored for illustrative parameters in the solar wind at the corona and at 1 AU. The evolution of the transverse waves shows the combined effects of local emission and propagation away from the source. At a given location, the emission rate shows a series of coalescences of Langmuir waves driven by the beam and those produced by successive decays. The effects of solar wind parameters on the emission are compared and discussed.
DE: 7534 Radio emissions
DE: 7839 Nonlinear phenomena
DE: 7843 Numerical simulation studies
DE: 7867 Wave/particle interactions
DE: 7868 Wave/wave interactions
SC: SPA-Solar and Heliospheric Physics [SH]
MN: 2004 AGU Fall Meeting