Mostrar el registro sencillo del ítem Woodman Pollitt, Ronald Francisco Chau Chong Shing, Jorge Luis
dc.coverage.spatial Jicamarca 2018-06-28T18:52:39Z 2018-06-28T18:52:39Z 2002-12-27
dc.identifier.citation Woodman, R. F., & Chau, J. L. (2002). First Jicamarca radar observations of two-stream E region irregularities under daytime counter equatorial electrojet conditions.==$Journal of Geophysical Research: Space Physics, 107$==(A12). es_ES
dc.identifier.govdoc index-oti2018
dc.description.abstract We report the first Jicamarca Radio Observatory (JRO) observations of two-stream irregularities under daytime counter equatorial electrojet (CEEJ) conditions, made with a VHF radar. This type of irregularity, although predicted by linear theory, has been observed only very few times at other sites (once in Africa and once in India). In the first 40 years of the existence of JRO, these irregularities were not observed. Since June 2000 and November 2001, we have observed them, surprisingly on seven different days. Our observations reveal that CEEJ irregularities appear only when large reversed zonal electric fields exist. We have used the horizontal component of the magnetic field due to the equatorial electrojet (H) as a proxy of the zonal electric fields. Initially, the CEEJ echoes are weak, with a Doppler velocity comparable to the ion-acoustic speed, and a relatively narrow spectral width and coming only from small elevation angles. As the ΔH value gets more negative (∼−200 nT around noon), very strong CEEJ echoes appear, still with ion-acoustic velocities at low elevation angles but with large spectral widths. The Doppler shifts of the spectra follow a dependence on the cosine of elevation angle. Weak CEEJ echoes are again observed when the irregularities are about to disappear (i.e., when H is just slightly negative of the threshold value). In order to get a better understanding of the scattering mechanism responsible for these echoes, we have devised a simple statistical model and compared its spectra to the spectral radar data. The CEEJ spectral characteristics can be explained on the basis of turbulent plasma breakdown of pure two-stream instabilities. These echoes are thought to be generated by nonlinear mode coupling and, when sufficiently strong, by secondary wave instabilities driven by pure two-stream waves at the density maximum and the topside of the E region. 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 Electrojet es_ES
dc.subject Irregularities es_ES
dc.subject Equatorial es_ES
dc.title First Jicamarca radar observations of two-stream E region irregularities under daytime counter equatorial electrojet conditions 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




Mostrar el registro sencillo del ítem