FAST Observations of Upflowing Ion Beams, Field-Aligned Currents and Electrostatic Ion Cyclotron Waves



C. A. Cattell, K. Sigsbee (School of Physics and Astronomy, University of Minnesota, Minneapolis, MN 55455)

C. W. Carlson, R. E. Ergun, J. P. McFadden, M. Temerin (Space Sciences Laboratory, University of California, Berkeley, CA 94720)

D. M. Klumpar (Lockheed Martin Palo Alto Research Laboratory, Palo Alto, CA)

E. Moebius, L. Tang (University of New Hampshire, Durham, NH 03824)

R. C. Elphic (Space and Atmospheric Sciences, Los Alamos National Lab, Los Alamos, NM 87545)

R. J. Strangeway (Institute of Geophysics and Planetary Physics, University of California, Los Angeles, CA 90024)

R. Bergmann (Eastern Illinois University)


Electrostatic ion cyclotron waves have been observed on auroral field lines by many satellites including S3-3, ISEE-1, Viking and Polar. Evidence for hydrogen, oxygen and helium cyclotron frequency waves has been presented. The waves are associated with field- aligned currents and upflowing ion beams (of variable composition), and theoretical mechanisms using either currents or ion beams or both have been proposed. In addition, in some cases, the observed electrostatic waves near the various ion gyrofrequencies may be due to relative streaming between ion species. The time, angular and species resolutions of the data available thus far, as well as lack of information on the background electron density and temperature, have not allowed the definitive identification of the free energy source for the waves. Utilizing data obtained by the FAST satellite which provides the necessary resolution, we will address these issues, as well as saturation mechanisms and effects on the evolution of the ion distributions.



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