First Jicamarca radar observations of two-stream E region irregularities under daytime counter equatorial electrojet conditions

摘要: [1] 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 irregularity, although predicted by linear theory, has been observed only very few times at other sites (once in Africa and once India). In 40 years existence JRO, these were not observed. Since June 2000 November 2001, we have them, surprisingly on seven different days. Our reveal that CEEJ appear when large reversed zonal electric fields exist. We used horizontal component magnetic field due to (ΔH) as proxy fields. Initially, echoes are weak, Doppler velocity comparable ion-acoustic speed, relatively narrow spectral width coming from small elevation angles. As ΔH value gets more negative (∼−200 nT around noon), strong appear, still velocities low angles but widths. The shifts spectra follow dependence cosine angle. Weak again about disappear (i.e., is just slightly threshold value). order get better understanding scattering mechanism responsible for echoes, devised simple statistical model compared its radar data. characteristics can be explained basis turbulent plasma breakdown pure instabilities. These thought generated nonlinear mode coupling and, sufficiently strong, secondary wave instabilities driven waves density maximum topside E region.