Proceedings with Extended Abstracts (single PDF file) - Radio ...

current continuity and map along the geomagnetic field. An ambient zonal electric field playsthe same role as the meridional neutral wind. The amplitudes are 5.3 and 3.2 mV/m onhorizontal and meridional-vertical planes, respectively. The polarization electric fields driveeastward Hall current within the plasma cloud. Since conductivity sharply drops at both edgesof the cloud, the eastern edge become positively charged and the western edge negatively. Atboth edges of the cloud, the current is connected with field-aligned currents that aredownward at the western edge and upward at the eastern edge. Around the center of theplasma cloud, the field-aligned current also flows in and out but the amplitude is smaller. As aresult, the current circuit is established between the plasma cloud in the lower E-region andthe upper boundary, that is, the equivalent F-region. After 60 s, field-aligned plasma structuresare formed, especially at the eastern and western edge of the plasma cloud.(a)(b)(b)(d)Figure 3. Results of numerical simulation for generation of polarization electric fields.4. CONCLUSIONSWe have studied electric fields in the ionospheric E-region by the rocket observation and thenumerical simulation. When Es layers have inhomogeneous structures, polarization electricfields can be generated by ambient electric fields or neutral winds. The generated polarization128