 |
Detailed Reference Information |
Doolittle, J.H., Mende, S.B., Robinson, R.M., Swenson, G.R. and Valladares, C.E. (1990). An observation of ionospheric convection and auroral arc motion. Journal of Geophysical Research 95: doi: 10.1029/90JA00552. issn: 0148-0227. |
|
An all-sky imager operated at Sondre Stromfjord, Greenland has been used to make auroral measurements in correlation with data from the incoherent scatter radar. The auroral images were recorded on video tape for later display as time lapse sequences. Reviewing the images as movie sequences with an apparent time compression ratio of 60 allows the eye to discern features which are not apparent in the individual frames. The faint 630 nm airglow background lying poleward of the bright auroral oval arcs appears to be structured in the time lapse observations and drifting at a uniform rate. Analysis of the motion of the airglow structures shows excellent agreement with Doppler radar measurement of the ion drift velocities. Electron density profiles derived from the radar data corroborate the existence of high altitude F-region ionization enhancements. The electron temperature in the patches was about 1000 K and no higher than outside of the patch signifying that the patches were not produced by local soft electron precipitation. According to the radar Doppler data there was a small component of the drift velocity parallel to the arc at either side of the auroral boundary. The sense of those small components was consistent with drifts driven by a convergent electric field which would also produce an up going field aligned current. The larger component of drift velocity perpendicular to the arc appeared to be continuous on either side of the arc. This drift component shows the existence of an electric field parallel to the arc, showing that the arc was not on an equipotential. During the observations the arc moved slowly in the opposite sense to the ion drift, signifying that the auroral arc motion is not driven by the electric field impressed on the atmosphere by the magnetosphere. Calculations of the expected intensity of the 630 nm emissions are in good agreement with the measured intensities of the moving patches. The observation of the motion of these airglow structures could provide a routine measurement of the ionospheric convection speeds in regions where the radar is not available. ¿ American Geophysical Union 1990 |
|
 |
 |
BACKGROUND DATA FILES |
|
 |
Abstract |
|
 |
|
|
|
Keywords
Ionosphere, Plasma convection, Ionosphere, Auroral ionosphere |
|
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 |
|
|
 |