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Detailed Reference Information |
Eliasson, L., André, M., Eriksson, A., Norqvist, P., Norberg, O., Lundin, R., Holback, B., Koskinen, H., Borg, H. and Boehm, M. (1994). Freja observations of heating and precipitation of positive ions. Geophysical Research Letters 21: doi: 10.1029/94GL01067. issn: 0094-8276. |
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The experiments on board Freja are designed to measure auroral particle energization processes with very high temporal and spatial resolution. One main scientific objective is to study ion heating transverse to the magnetic field lines in the auroral region. The Freja orbit with an inclination of 63¿ allows us to make detailed measurements in the nightside auroral oval during all disturbance levels. We concentrate hear on two different observations of transverse ion energization at an altitude of about 1700 km in the northern hemisphere auroral region. The three-dimensional ion mass spectrograph has shown that both heavy and light ions are heated to energies most often in the range from a few eV to some hundred eV. Transversely heated ions are, however, also seen up to the present high energy limit of the hot plasma instrument, 4.5 keV. Ion conics are produced in regions with anisotropic electron fluxes as well as in regions of intense keV proton precipitation. Waves above the lower hybrid frequency are observed in the events presented in this presented in this report. These waves may play an important role in the ion heating process. The Freja data indicate that the waves are generated in different ways in these events. Thus this preliminary investigation confirms that several scenarios are needed to explain the heating of ionospheric plasma and shows some of the possibilities for future studies. ¿ American Geophysical Union 1994 |
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BACKGROUND DATA FILES |
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Abstract |
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Keywords
Ionosphere, Particle acceleration, Magnetospheric Physics, Auroral phenomena, Magnetospheric Physics, Magnetosphere-ionosphere interactions, Space Plasma Physics, Wave-particle interactions |
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Publisher
American Geophysical Union 2000 Florida Avenue N.W. Washington, D.C. 20009-1277 USA 1-202-462-6900 1-202-328-0566 service@agu.org |
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