Ring current 0+ Interaction with PC 5 Micropulsations

  1. Gordon R. Wilson
  1. S. Qian1,
  2. M. K. Hudson1 and
  3. I. Roth2

Published Online: 18 MAR 2013

DOI: 10.1029/GM062p0143

Modeling Magnetospheric Plasma Processes

Modeling Magnetospheric Plasma Processes

How to Cite

Qian, S., Hudson, M. K. and Roth, I. (1991) Ring current 0+ Interaction with PC 5 Micropulsations, in Modeling Magnetospheric Plasma Processes (ed G. R. Wilson), American Geophysical Union, Washington, D. C.. doi: 10.1029/GM062p0143

Author Information

  1. 1

    Department of Physics and Astronomy, Dartmouth College, Hanover, New Hampshire 03755

  2. 2

    Space Sciences Laboratory, University of California at Berkeley, Berkeley, California, 94720

Publication History

  1. Published Online: 18 MAR 2013
  2. Published Print: 1 JAN 1991

ISBN Information

Print ISBN: 9780875900285

Online ISBN: 9781118663905



  • Space plasmas—Mathematical models—Congresses;
  • Magnetosphere—Mathematical models—Congresses


Pc 5 ULF micropulsations in the few mHz frequency range have been measured by satellite observations during and after a geomagnetic storm. Rapid loss of ring current oxygen during the recovery phase of the storm was observed by ISEE-1. The loss of oxygen ions was attributed to an interaction of oxygen with micropulsations, which have the same period as the oxygen bounce time. A test particle model is used here to study this drift-bounce resonant interaction. In this model test particles move in the dipole magnetic field of the earth, with corotation and convection electric fields included, along with compressional Pc 5 wave fields. Studies of H+ and 0+ orbits show that the wave interacts strongly with low energy ring current 0+ (tens of keV) and has little effect on H+ below 100 keV. The convection electric field plays an important role in tuning the resonance condition ω b =±(mω d -ω), since the bounce and drift frequencies are energy dependent. The drift-bounce resonant interaction and oscillations of the particle energy, L value and first adiabatic invariant are studied for different wave modes, ion energies and pitch angles. It is suggested that this interaction may be responsible for loss from the ring current of low energy O+ satisfying the resonance condition.