| 1. |
- Pellinen-Wannberg, Asta, et al.
(författare)
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E region ionization enhancement over northern Scandinavia during the 2002 Leonids
- 2014
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Ingår i: 2014 XXXITH URSI GENERAL ASSEMBLY AND SCIENTIFIC SYMPOSIUM (URSI GASS). - : IEEE. - 9781467352253
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Konferensbidrag (refereegranskat)abstract
- Intensive E-region ionization was observed with the EISCAT UHF radar during the 2002 Leonids meteor shower. The levels of the geomagnetic disturbance were low during the event. Thus the ionization cannot be explained by intensive precipitation. The layer was 30-40 km thick, so it cannot be classified as a sporadic E-layer (often associated to ions of meteoric origin). These are typically only about km-wide. Incoherent scatter radars have never so far reported any notable meteor shower-related increases in the average background ionization. The 2002 Leonid storm flux, however, was so high that it, if any, might be able to induce such an event. Whether meteors in general can cause such an excess E-region ionization during an intensive shower is discussed. The University of Leeds CABMOD model is used to estimate deposition rates of individual meteors and to relate the results to the predicted Leonid flux values in free space and observed ionization on November 19, 2002.
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| 2. |
- Pellinen-Wannberg, Asta K., et al.
(författare)
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Strong E region ionization caused by the 1767 trail during the 2002 Leonids
- 2014
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Ingår i: Journal of Geophysical Research - Space Physics. - 2169-9380 .- 2169-9402. ; 119:9, s. 7880-7888
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Tidskriftsartikel (refereegranskat)abstract
- Intensive E region ionization extending up to 140 km altitude and lasting for several hours was observed with the European Incoherent Scatter (EISCAT) UHF radar during the 2002 Leonids meteor shower maximum. The level of global geomagnetic disturbance as well as the local geomagnetic and auroral activity in northern Scandinavia were low during the event. Thus, the ionization cannot be explained by intensive precipitation. The layer was 30-40 km thick, so it cannot be classified as a sporadic E layer which are typically just a few kilometers wide. Incoherent scatter radars have not to date reported any notable meteor shower-related increases in the average background ionization. The 2002 Leonids storm flux, however, was so high that it might have been able to induce such an event. The Chemical Ablation Model is used to estimate deposition rates of individual meteors. The resulting electron production, arising from hyperthermal collisions of ablated atoms with atmospheric molecules, is related to the predicted Leonid flux values and observed ionization on 19 November 2002. The EISCAT Svalbard Radar (ESR) located at some 1000 km north of the UHF site did not observe any excess ionization during the same period. The high-latitude electrodynamic conditions recorded by the SuperDARN radar network show that the ESR was within a strongly drifting convection cell continuously fed by fresh plasma while the UHF radar was outside the polar convection region maintaining the ionization.
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