EarthRef.org Reference Database (ERR)
Development and Maintenance by the EarthRef.org Database Team

Detailed Reference Information
Rae et al. 2001
Rae, I.J., Lester, M., Milan, S.E., Fritz, T.A., Grande, M. and Scudder, J.D. (2001). Polar observations of the time-varying cusp. Journal of Geophysical Research 106: doi: 10.1029/2000JA003015. issn: 0148-0227.

We present a multi-instrument case study of the signatures associated with the cusp observed by the Charge and Mass Magnetospheric Ion Composition Experiment (CAMMICE), Hot Plasma Analyzer (HYDRA) and Magnetic Fields Experiment (MFE) instruments onboard the Polar satellite between 0900 and 1300 UT on October 29, 1996. Characteristic signatures of the midaltitude cusp include ions of energies 102--104 eV, electrons of energies 10--103 eV, and a structured depression in the local magnetic field. During this cusp pass, ion fluxes in the 1--20 keV range were modulated quasi-periodically on timescales of between 12 and 20 min, while energy-dispersed ion count rates were observed close to the open-closed field line boundary. The particle populations on the cusp field lines are dominated by H+ and He++ ions (characteristic of magnetosheath-like plasma), and on closed field lines dominated by uniform fluxes of high-energy (50--200 keV) protons, which are not pulsed. The pulsed particle events during this case study occur during both southward and northward interplanetary magnetic field (IMF), but differ slightly in nature. After the IMF rotated northward, Polar still observed the pulsed particle events, but magnetosheath-like and closed field line particles coexisted on the same magnetic flux tubes. It is not evident as to how this mix of plasma can exist on the same field line during northward IMF. HYDRA also observed higher-frequency pulsing, hypothesized to be caused by low-latitude transient magnetic reconnection. The simultaneous observation of two different frequency components has not been previously reported in spacecraft observations of the midaltitude cusp. Two further cusp passes during similar conditions are presented. The short-period pulsed particle signatures were observed in all three examples, the longer-period pulsing observed in two. The events differed in duration, most likely owing to the effect of IMF By on the location of the reconnection site, and hence the location of the polar cusp. ¿ 2001 American Geophysical Union

BACKGROUND DATA FILES

Abstract

Keywords
Magnetospheric Physics, Energetic particles, trapped, Magnetospheric Physics, Magnetopause, cusp, and boundary layers, Magnetospheric Physics, Solar wind/magnetosphere interactions
Journal
Journal of Geophysical Research
http://www.agu.org/journals/jb/
Publisher
American Geophysical Union
2000 Florida Avenue N.W.
Washington, D.C. 20009-1277
USA
1-202-462-6900
1-202-328-0566
service@agu.org
Click to clear formClick to return to previous pageClick to submit