Ponderomotive effects on distributions of O+ ions in the auroral zone Journal Article uri icon



  • Test particle calculations are used to compute the effects of gravity and ponderomotive acceleration by shear Alfvén wave oscillations on the distribution function of O+ ions along auroral field lines, assuming an ionospheric Maxwellian source of the ions at 2000 km altitude with ∼0.5 eV of thermal energy in the parallel component of velocity. The electric field model corresponds to a standing wave oscillation with a frequency ∼1 Hz in the azimuthal direction superimposed on the background dipole field, in which the wave amplitude is either increasing or decreasing in time. The electric field is taken to be primarily in the perpendicular direction. The time varying wave produces broad distributions with widths of 2 to 10 times the initial 0.5‐eV thermal energy of the Maxwellian source, and the density and flux of upward going O+ ions at one Earth radius are both enhanced in this model. The oxygen ion distribution functions at 1 RE altitude resulting from interaction with waves whose amplitudes are increasing in time have a more gradual lower energy cutoff than do the distribution functions resulting from decaying waves. The high‐energy part of the distribution functions in growing waves reflects the temperature of the Maxwellian source, while the high‐energy part of the distributions resulting from decaying waves steepens with time, independent of the source temperature.

publication date

  • July 1, 1995

has restriction

  • closed

Date in CU Experts

  • March 26, 2014 9:57 AM

Full Author List

  • Witt E; Hudson MK; Li X; Roth I; Temerin M

author count

  • 5

Other Profiles

International Standard Serial Number (ISSN)

  • 0148-0227

Additional Document Info

start page

  • 12151

end page

  • 12161


  • 100


  • A7