Location of Repository

Excitation thresholds of field-aligned irregularities and associated ionospheric hysteresis at very high latitudes observed using SPEAR-induced HF radar backscatter

By D. M. Wright, R. S. Dhillon, Tim K. Yeoman, T. R. Robinson, E. C. Thomas, L. J. Baddeley and S. Imber

Abstract

On 10 October 2006 the SPEAR high power radar facility was operated in a power-stepping mode where both CUTLASS radars were detecting backscatter from the SPEAR-induced field-aligned irregularities (FAIs). The effective radiated power of SPEAR was varied from 1–10 MW. The aim of the experiment was to investigate the power thresholds for excitation (Pt) and collapse (Pc) of artificially-induced FAIs in the ionosphere over Svalbard. It was demonstrated that FAI could be excited by a SPEAR ERP of only 1 MW, representing only 1/30th of SPEAR's total capability, and that once created the irregularities could be maintained for even lower powers. The experiment also demonstrated that the very high latitude ionosphere exhibits hysteresis, where the down-going part of the power cycle provided a higher density of irregularities than for the equivalent part of the up-going cycle. Although this second result is similar to that observed previously by CUTLASS in conjunction with the Tromsø heater, the same is not true for the equivalent incoherent scatter measurements. The EISCAT Svalbard Radar (ESR) failed to detect any hysteresis in the plasma parameters over Svalbard in stark contract with the measurements made using the Tromsø UHF

Publisher: Copernicus Publications on behalf of the European Geosciences Union (EGU)
Year: 2009
DOI identifier: 10.5194/angeo-27-2623-2009
OAI identifier: oai:lra.le.ac.uk:2381/8226
Journal:

Suggested articles

Preview

Citations

  1. (1983). A hysteresis effect in the generation of field-aligned irregularities by a highpower radio wave, doi
  2. (1983). A thermal oscillating two-stream instability, doi
  3. (1995). DARN/SuperDARN: a global view of the dynamics of highlatitude convection, doi
  4. (1974). Field-aligned scattering from a heated region of the ionosphere: observations at HF and VHF, doi
  5. (2006). First observations of SPEAR-induced artificial backscatter from CUTLASS and the EISCAT Svalbard radars, doi
  6. (2006). Heater-induced altitude descent of the EISCAT UHF ion line enhancements: observations and modelling, doi
  7. (1997). High spatial and temporal resolution observations of an impulse-driven field line resonance in radar backscatter artificially generated with the Tromsø heater, doi
  8. (1978). Hysteresis effect in the artificial excitation of inhomogeneities in the ionospheric plasma, Radiophysics and Quantum Electronic (Engl. doi
  9. (1934). Influence of electric waves in the ionosphere, doi
  10. (1997). Initial backscatter occurrence statistics from the CUTLASS HF radars, doi
  11. (1933). Interaction between radio waves?, doi
  12. (2000). Measurements of HF-enhanced plasma and ion lines at EISCAT with high-altitude resolution, doi
  13. (1978). Non-linear Phenomena in the Ionosphere, doi
  14. (1997). O- and X-mode heating effects observed simultaneously with the CUTLASS and EISCAT radars and low power HF diagnostics at Tromsø,
  15. (1974). Radio frequency scattering from a heated ionospheric volume, 1, VHF/UHF fieldaligned and plasma line backscatter measurements, doi
  16. (1977). Resonance instability of smallscale plasma perturbations,
  17. (1996). Review of ionospheric modification experiments at Tromsø, doi
  18. (2006). Saturation and hysteresis effects in ionospheric modification experiments observed by the CUTLASS and EISCAT radars, doi
  19. (1997). Small-scale magnetic fieldaligned density irregularities excited by a powerful electromagnetic wave, doi
  20. (2000). Space Plasma Exploration by Active Radar (SPEAR): an overview of a future radar facility, doi
  21. (1995). Stationary striations developed in the ionospheric modification, doi
  22. (1997). The EISCAT Svalbard radar: a case study in modern incoherent scatter radar system design, doi
  23. (1989). The heating of the high latitude ionosphere by high power radio waves, doi
  24. (1978). Thermal parametric instability in an inhomogeneous plasma (nonlinear theory), doi
  25. (2009). Wright et al.: Excitation thresholds of field-aligned irregularities doi

To submit an update or takedown request for this paper, please submit an Update/Correction/Removal Request.