Ionospheric scintillations and in-situ measurements at an auroral location in the European sector
Abstract
The orbiting HiLat satellite launched by the Defense Nuclear Agency in 1983 offered an opportunity for studying the ionospheric scintillation parameters in relation to the in-situ measurements of ionization density, drift velocity, field-aligned current, and particle precipitation during the sunspot minimum period. The results of such a morphological study performed by the Air Force Geophysics Laboratory based on their observations at the auroral oval station of Tromso, Norway are discussed. The dynamics of the spatial and temporal extent of this region are illustrated in the invariant latitude/magnetic local time grid. The geometrical enhancement of scintillations observed during the alignment of the propagation path with the local magnetic L-shell is shown to be the most consistent and conspicuous feature of scintillations in the nighttime auroral oval. The steepening of phase spectral slope in this region is indicative of the presence of L-shell aligned sheet-like irregularities at long scale lengths. The seasonal variation of total electron content (TEC) determined from the differential Doppler measurements of HiLat transmissions is discussed in relation to in-situ density measurements at 830 km. The results are also utilized to illustrate the dependence of ionospheric structure parameters on short-term variability of solar activity during the sunspot minimum period. Special effort is made to illustrate that the joint study of scintillation/TEC and in-situ parameters provides an insight into the nature of magnetospheric coupling with the high latitude ionosphere.
- Publication:
-
In AGARD
- Pub Date:
- March 1988
- Bibcode:
- 1988sprm.agarT....B
- Keywords:
-
- Anomalies;
- Auroras;
- Magnetosphere-Ionosphere Coupling;
- Scintillation;
- Annual Variations;
- Electron Density (Concentration);
- Ionization;
- Space-Time Functions;
- Geophysics