A new scenario applying traffic flow analogy to poleward expansion of auroras

Transient westward electric fields from the magnetosphere generate equatorward plasma drifts of the order of kilometers per second in the auroral ionosphere. This flow channel extends in north–south directions and is produced in the initial pulse of Pi2 pulsations associated with the field line dipolarization. Drifts in the ionosphere of the order of kilometers per second that accumulated plasmas at the low-latitude end of the flow channel are of such large degree that possible vertical transport effects (including precipitation) along the field lines may be ignored. In this condition, we suggest that plasma compression in the ionosphere initiated the dynamic ionosphere. The dynamic ionosphere includes a nonlinear evolution of the compressed ionospheric plasmas, generation of field-aligned currents to satisfy the quasi-neutrality of the ionosphere, and parallel potentials associated with the excitation of an ion acoustic wave. We will study how the dynamic ionosphere created auroral expansion.

Polarization dynamics of Pi2 pulsations at midlatitudes during development of substorms in the auroral zone

We examine the changes in the orientation of the major axis of the polarization ellipse of irregular geomagnetic pulsations Pi2, observed at midlatitudes during a substorm disturbance developing in the auroral zone of the Russian Arctic sector. We have found the dependence of the polarization ellipse orientation on the longitude of a corresponding substorm. The results of current studies are compared with earlier results of similar studies using materials on the North American continent. We have concluded that the results are similar in general, with a slight discrepancy which may be due to peculiarities of the geological structure of the earth crust in the Russian Arctic sector.

Polarization dynamics of Pi2 pulsations at midlatitudes during development of substorms in the auroral zone

We examine the changes in the orientation of the major axis of the polarization ellipse of irregular geomagnetic pulsations Pi2, observed at midlatitudes during a substorm disturbance developing in the auroral zone of the Russian Arctic sector. We have found the dependence of the polarization ellipse orientation on the longitude of a corresponding substorm. The results of current studies are compared with earlier results of similar studies using data on the North American continent. We have concluded that the results are similar in general, with a slight discrepancy which may be due to peculiarities of the geological structure of the earth crust in the Russian Arctic sector.