On a possibility of existence of two and more sources Pi2- pulsations in the magnetosphere
Abstract
Geomagnetic Pi2 pulsations represent irregular oscillations in the range of periods from 20 to 200 s which accompany the onset of the active phase of magnetospheric substorm and attain maximum amplitudes as large as a hundred nT in the aurora zone The Pi2 intensity decreases poleward and toward mid-latitudes Also there is a secondary maximum at the latitudes of plasmapause projection Dynamic spectra of the pulsations that accompany the beginning of the active phase of substorm in the midnight sector in high latitudes have the form of a noisy spike whereas the spectrum width is rather limited in mid-latitudes Further it should be noted that there is one further zone where the excitation of these pulsations can be different from high and mid-latitudes It is the region of the geomagnetic equator We have investigated near-equatorial pulsations and have found out the following In some cases the increase of amplitude is observed in near-equatorial fluctuations in relation to pulsations of mid-latitudes The difference between the Pi2 pulsation generation patterns in the auroral zone mid-latitudes and near- equatorial regions supports our earlier suggestion of a possible existence of several Pi2 pulsation sources The following scenario is likeliest for Pi2 pulsation development during magnetospheric disturbances Substorm is an agent stimulating generation of these fluctuations The source of high-latitude Pi2s can be provided by processes in field tubes adjacent to the electrojet development region in the auroral
- Publication:
-
36th COSPAR Scientific Assembly
- Pub Date:
- 2006
- Bibcode:
- 2006cosp...36..898R