Mostrar el registro sencillo del ítem Kudeki, Erhan Farley, Donald T. 2018-07-06T17:01:49Z 2018-07-06T17:01:49Z 1989-01-01
dc.identifier.citation Kudeki, E., & Farley, D. T. (1989). Aspect sensitivity of equatorial electrojet irregularities and theoretical implications.==$Journal of Geophysical Research: Space Physics, 94$==(A1), 426-434. es_ES
dc.description.abstract We used a multi baseline 50-MHz radar interferometer at the Jicamarca Radio Observatory to study the dependence of echo strength on the aspect angle, the angle of arrival relative to normal to the geomagnetic field. We observed rms values of this angle in the range 0.1–0.4, which implies an aspect sensitivity somewhat greater than the nominal 10 dB/deg often quoted for auroral echoes. The technique has sufficient resolution to allow deviations from normal of less than 0.1 to be measured fairly easily, and we were able to determine variations of the aspect sensitivity with altitude, Doppler shift, and electrojet conditions. During weakly driven periods, when only type 2 echoes were observed, the width, or rms angular deviation from normal, decreased monotonically with increasing altitude, as simple linear theory would suggest, but the variation was less rapid than the variation of νe/Ωe, especially on the bottomside of the electrojet. A particularly interesting observation was that, during strongly driven type 1 conditions, there was a pronounced variation of width with Doppler shift. The width for small phase velocities was sometimes more than twice that at the ion-acoustic velocity. We believe that this broadening is due to nonlinear three-wave mode coupling which produces a reverse cascade of energy from short wavelengths to long and an increase in the mean aspect angle. Such a cascade represents an increase in the effective diffusion coefficient for the short wavelength waves and so could provide an explanation alternative to that of the anomalous collision process of Sudan (1983) for the limitation of the type 1 phase velocity at the ion-acoustic velocity. es_ES
dc.format application/pdf es_ES
dc.language.iso eng es_ES
dc.publisher American Geophysical Union es_ES
dc.relation.ispartof urn:issn:2169-9380
dc.rights info:eu-repo/semantics/restrictedAccess es_ES
dc.subject Equatorial electrojet es_ES
dc.subject Echoes es_ES
dc.subject Interferometry es_ES
dc.title Aspect sensitivity of equatorial electrojet irregularities and theoretical implications es_ES
dc.type info:eu-repo/semantics/article es_ES
dc.subject.ocde es_ES
dc.identifier.journal Journal of Geophysical Research: Space Physics es_ES
dc.description.peer-review Por pares es_ES
dc.identifier.doi es_ES




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