A multi-point perspective on the formation of polar cap arcs: kinetic modeling and observations by Cluster and TIMED

Details A multi-point perspective on the formation of polar cap arcs: kinetic modeling and observations by Cluster and TIMED A multi-point perspective on the formation of polar cap arcs: kinetic modeling and observations by Cluster and TIMED

Dec 2010

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2010agufmsm21a1879d&link_type=abstract

American Geophysical Union, Fall Meeting 2010, abstract #SM21A-1879

Physics

[2455] Ionosphere / Particle Precipitation, [2475] Ionosphere / Polar Cap Ionosphere, [2704] Magnetospheric Physics / Auroral Phenomena, [2736] Magnetospheric Physics / Magnetosphere/Ionosphere Interactions

Scientific paper

On April 1st, 2004 the GUVI imager onboard the TIMED spacecraft spots an isolated and elongated polar cap arc. Simultaneously, the Cluster spacecraft detects an isolated upflowing ion beam above the polar cap. Cluster observations show that the ions are accelerated upward by a quasi-stationary electric field. The field-aligned potential drop is estimated to about 600 V and the upflowing ions are accompanied by a tenuous population of isotropic protons with a temperature of about 300eV. The footprint of the magnetic field line on which the Cluster spacecraft are situated, is located just outside the GUVI field of view in the prolongation of the polar cap arc. This suggests that the upflowing ion beam and the polar cap arc may be different signatures of the same phenomenon, as suggested by a recent statistical study of polar cap ion beams using Cluster data. We use Cluster observations at high altitude as input to a quasi-stationary magnetosphere-ionosphere (MI) coupling model. Using a Knight-type current-voltage relationship and the current continuity at the topside ionosphere, the model computes the energy spectrum of precipitating electrons at ionospheric altitudes corresponding to the generator electric field observed by Cluster. The MI coupling model provides a field-aligned potential drop in agreement with Cluster observations of upflowing ions and a spatial scale of the polar cap arc consistent with the optical observations by TIMED. The energy spectrum of the precipitating electrons provided by the model is introduced as input to the Trans4 ionospheric transport code. This 1-D model, based on Boltzmann's kinetic formalism, takes into account ionospheric processes like photoionisation and electron/proton precipitation, and computes the optical and UV emissions due to precipitating electrons. The emission rates provided by the Trans4 code are then compared to the optical observations by TIMED. Data and modeling results are consistent with quasi-static acceleration of precipitating magnetospheric electrons. We also discuss possible implications of our modeling results for optical observations of polar cap arcs.

Affiliated with

Also associated with

No associations

Rating

A multi-point perspective on the formation of polar cap arcs: kinetic modeling and observations by Cluster and TIMED does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with A multi-point perspective on the formation of polar cap arcs: kinetic modeling and observations by Cluster and TIMED, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and A multi-point perspective on the formation of polar cap arcs: kinetic modeling and observations by Cluster and TIMED will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1468191