Determination by triangulation of the regions where whistlers emerge from the ionosphere
Abstract
Observations made on 10 July 1972, using four goniometer (direction-finding) VLF receivers in eastern Canada, were analyzed. The regions where multicomponent, two-hop whistlers emerge from the ionosphere into the earth-ionosphere waveguide were found by triangulation. For recordings made before the total solar eclipse, the L-values of the whistler exit points determined by triangulation are consistently lower than those determined from their nose frequencies. This discrepancy cannot be fully accounted for by the effect of the ring current. To explain it, it is postulated that on this occasion the electron-density trough in the topside ionosphere lies at a lower L-value than that of the plasmapause. Ray-tracing studies show that, on the high-latitude side of the trough, the waves are refracted to higher L-values before becoming ducted. Thus the multigoniometer technique is proving to be a powerful method for studying both temporal and spatial variations of the ionospheric and magnetospheric plasmas.
- Publication:
-
European Sounding Rocket and Scientific Balloon Activity at High Latitudes, with Emphasis on the International Magnetospheric Study (IMS)
- Pub Date:
- February 1975
- Bibcode:
- 1975srbr.rept..225R
- Keywords:
-
- Triangulation;
- Very Low Frequencies;
- Whistlers;
- Canada;
- Geos Satellites (Esa);
- Ground Based Control;
- Lower Ionosphere;
- Plasmapause;
- Project Planning;
- Radiogoniometers;
- Ray Tracing;
- Satellite Observation;
- Sonograms;
- Waveforms;
- Whistler Recorders;
- Communications and Radar