تقرير
Patches in the polar ionosphere: UT and seasonal dependence
| العنوان: | Patches in the polar ionosphere: UT and seasonal dependence |
|---|---|
| المؤلفون: | Sojka, J. J, Bowline, M. D, Schunk, R. W |
| المصدر: | Journal of Geophysical Research. 99(A8) |
| بيانات النشر: | United States: NASA Center for Aerospace Information (CASI), 1994. |
| سنة النشر: | 1994 |
| مصطلحات موضوعية: | Geosciences (General) |
| الوصف: | The seasonal and Universal Time (UT) dependencies of patches in the polar ionosphere are simulated using the Utah State University time dependent ionospheric model (TDIM). Patch formation is achieved by changing the plasma convection pattern in response to temporal changes in the interplanetary magnetic field (IMF) B(sub y) component during periods of southwrd IMF. This mechanism redirects the plasma flow from the dayside high-density region, which is the source of the tongue of ionization (TOI) density feature, through the throat and leads to patches, rather than a continuous TOI. The model predicts that the patches are absent at winter solstice (northern hemisphere) between 0800 and 1200 UT and that they have their largest seasonal intensity at winter solstice between 2000 and 2400 UT. Between winter solstice and equinox, patches are strong and present all day. Patches are present in summer as well, although their intensity is only tens of percent above the background density. These winter-to-equinox findings are also shown to be consistent with observations. The model was also used to predict times at which patch observations could be performed to determine the contributions from other patch mechanisms. This observational window is +/- 20 days about winter solstice between 0800 and 1200 UT in the northern hemisphere. In this observational window the TOI is either absent or reduced to a very low density. Hence the time dependent electric field mechanism considered in this study does not produce patches, and if they are observed, then they must be due to some other mechanism. |
| نوع الوثيقة: | Report |
| اللغة: | English |
| تدمد: | 0148-0227 |
| DOI: | 10.1029/93JA03327 |
| URL الوصول: | https://ntrs.nasa.gov/citations/19950053339 |
| ملاحظات: | NAG5-1484 NSF ATM-93-08163 NSF ATM-89-13230 NSF ATM-93-02165 |
| رقم الأكسشن: | edsnas.19950053339 |
| قاعدة البيانات: | NASA Technical Reports |
| تدمد: | 01480227 |
|---|---|
| DOI: | 10.1029/93JA03327 |