Bayreuth 1998 – scientific programme

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P: Plasmaphysik

P 19: Theorie III

P 19.7: Talk

Wednesday, March 11, 1998, 17:30–17:45, H 6

Electrostatic ion-cyclotron turbulence and anomalous resistivity in the plasma of the auroral magnetosphere — •V.E. Zakharov¹ and C.-V. Meister² — ¹Kaliningrad State Univ. — ²Astrophys. Inst. Potsdam

The electron components of intense electric currents flowing along the geomagnetic field lines excite turbulence in the thermal magnetospheric plasma. The protons are then scattered by the turbulent electromagnetic waves, and as a result the plasma is stable. As the electron and ion temperatures of the background plasma are approximately equal each other, in this work electrostatic ion-cyclotron (EIC) turbulence is considered. In the nonisothermal plasma the ion-acoustic turbulence may occur additionally. The resulting anomalous resistivity causes large-scale differences Δ V of the electrostatic potential along the magnetic field lines. The presence of Δ V provides heating and acceleration of the thermal and energetic auroral plasma. The investigation of the energy and momentum balance of the plasma and waves in the turbulent region is performed numerically taking into account magnetospheric convection and thermal conductivity of the plasma. As shown for the quasi-steady state, the presence of EIC turbulence may provide potential differences Δ V≈ 1−10 kV at altitudes of 500<h<10000 km above the earth’s surface. In the turbulent region, the temperatures of the electrons and protons increase not more than a few times in comparison with the background values.