The discovery of a second type of ion conic
distribution and the determination of its occurrence patterns.
References
Klumpar et al. (1984) reported a second type of "ion conic" distribution.
This "bi-modal" distribution was characterized by an "extended range"
of pitch angles. Until the Klumpar et al. report, it was assumed
that an ion conics conic was characterized by a single pitch angle and
the distance below the spacecraft where the ions were energized
was uniquely determined from the conic angle. Klumpar et al. showed
that the distribution could be formed by two independent processes
acting on the same field line energizing ions parallel and perpendicular
to the magnetic field.
Several other mechanisms have been shown to produce "extended" or
"bi-modal" ion distributions including the
Ion Resonance Heating (ICRH) mechanism
Peterson et al. developed an automated conic finding algorithm and
search the DE/EICS data base for extended (i.e. bi-modal) and
restricted (i.e. classic) conic distributions.
Results from the large scale studies are given in the
papers noted below.
References (In alphabetical order by first author)
-
Doherty, MF, C.M. Bjorklund, W.K. Peterson, and H.L. Collin, Automated
detection of mass-resolved ion conics, IEEE Transactions on Geoscience and
Remote Sensing, 31, 407, 1993.
-
Klumpar, D. M., W. K. Peterson, and E. G. Shelley, Direct evidence for
two-stage (bimodal) acceleration of ionospheric ions, J. Geophys. Res., 89,
10, 779, 1984.
-
Peterson, W.K., H.L. Collin, M.F. Doherty and C.M. Bjorklund, O+ and He+
restricted and extended (bi-modal) ion conic distributions, Geophys. Res.
Lett., 19, 1439, 1992.
-
Peterson, W.K., H.L. Collin, M.F. Doherty and C.M. Bjorklund, Extended
(bi-modal) ion conics at high altitudes, Space Plasmas: Coupling Between Small and Medium Scale Processes, Geophysical Monograph 86, p 105, American
Geophysical Union, Washington DC, 1995.
Last updated October, 1995 by W.K. Peterson