Bonn 2010 – wissenschaftliches Programm

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EP: Fachverband Extraterrestrische Physik

EP 7: Fundamental Physics

EP 7.5: Vortrag

Dienstag, 16. März 2010, 16:00–16:15, AKM

Anomalous momentum transport and plasma heating in collisionless return-current beam plasma system: multi-fluid and kinetic approaches — •Kuang Wu Lee and Jörg Büchner — Max-Planck-Institut für Sonnensystemforschung, Max-Planck-Str. 2, 37191 Katlenburg-Lindau, Germany

The anomalous transport in a one dimensional, collisionless return-current beam plasma system is studied by means of electrostatic Vlasov and three-fluid simulations. A current-free condition is applied and mimics the counter-streaming electron beams. The electron bulk drifts are dissipated due to anomalous momentum transport and electron heating. The spectrum of generated electric field fluctuations proves the charge separation effects play a major role as anomalous transport in the multi-fluid plasma. To investigate the dissipation mechanism in kinetic scale, a 1D electrostatic Vlasov code simulation is performed with same macroscopic plasma parameters. The comparison of the two different approaches shows that a much stronger drift relaxation takes place in the multi-fluid plasma approach. It was found that it spends within the same time span (△ t≈ 700 ωpe−1) to reach the same drift relaxation levels in two different approaches. This hints that charge-separation is a common mechanism of generating anomalous transport in multi-fluid plasma descriptions. By carrying out a wave-particle interaction analysis, it was shown that in kinetic plasma description Landau damping play a role to stop further current dissipation. In conclusion we obtained that an additional anomalous transport term is required for a complete multi-fluid plasma description.

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