Fennell, J. F.,
Co-Authors: M. W. Chen, J. L. Roeder, W. K. Peterson, K. J. Trattner, R. Friedel*, S. Livi, M. Grande, C. Perry, T. A. Fritz, and R. Sheldon,
Title: Multiple Discrete-Energy Ion Features in the Inner Magnetosphere: Polar Observations,
Reference: in PHYSICS OF SPACE PLASMAS, No. 15, p 395-400, MIT Center for Theoretical Geo/Cosmo Plasma Physics, Cambridge, MA, 1998.
Reference Type: Published Journal
CEPPAD: true
CAMMICE: true
RAPID: false
Abstract:
The Polar satellite traverses the inner magnetosphere twice in 18 hours. On many traversals of the inner magnetosphere multiple peaked spectra are observed by the ion composition sensors (CAMMICE/MICS and Timas) with peaks in the energy ranges near 10-20, 35-50, and 90-120 keV as Polar moves from high L to cross the equator near L = 2.5-3.5. These multi-peaked spectra are observed most often on the dayside (6-18 MLT) and the peaks appear as traces that extend from large to small L values. They are similar to classic ‘nose’ events except for the multiplicity of discrete energy peaks or ‘traces’ that extend over a wide L range. For example, on February 9, 1998 the MICS ob-served such traces extending from L = 7 to 3.5 that had at least 4 discrete energy peaks in H+ near 3.5, 18, 32 and 90 keV/q at L = 3.5. The three lowest energy peaks were also observed in He and O+. These were well below the ~L-3 trace corresponding to the peak energy of the quiet time ring current,! ! ! which had a broad spectral peak in the H+ near 400 keV at L~3.5. These discrete energy traces may be consistent with the motion of ions inward from the magne-totail during a period that had a fluctuating cross polar cap electric field. However, standard particle tracing in com-bined model electric and magnetic fields can only explain some but not all these discrete energy traces. The lowest energy ion features appear to be correspond to ‘banana’ type closed drift shells near the earth as predicted by standard particle trajectory calculations.
