Leipzig 2002 – wissenschaftliches Programm
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EP: Extraterrestrische Physik
EP 2: Extraterrestrik-Poster
EP 2.4: Poster
Montag, 18. März 2002, 13:30–14:30, Galerie 1
Acceleration and heating in the auroral magnetosphere by ion cyclotron turbulence — •Claudia-Veronika Meister1 and Venjamin Zakharov2 — 1Space Plasma Physics, Potsdam, Germany — 2Kaliningrad State University, Russia
A numerical MHD model is developed to investigate acceleration and heating of both thermal and auroral plasma. This is done for magnetospheric flux tubes in which intensive field aligned currents flow. Performing the numerical calculations, the distributions of the plasma densities, velocities, temperatures, parallel electric field and current, and of the coefficients of thermal conductivity are obtained in a self-consistent way. It is found that the ion-cyclotron turbulence developes effectively in the thermal plasma. The parallel electric field developes under the action of the anomalous resistivity, and it accelerates both the thermal and the auroral plasma. The thermal turbulent plasma is also subject to an intensive heating. The increase of the plasma temperature strongly depends on the value of the magnetic flux in the tube and on the intensity of the magnetospheric convection. It is found that even stationary electrostatic turbulence may cause the large-scale resistivity of the plasma of the Earth’s ionosphere. Besides the dispersion equation of electromagnetic ion-cyclotron waves was solved for the case of the auroral magnetosphere, and it was found that growth rates of such waves may be of the order of the wave frequency. Thus, under non-stationary conditions electromagnetic ion-cyclotron waves may reveal the properties of bursts of polarized transverse electromagnetic waves at frequencies near the proton gyrofrequency.