Location of Repository

Aspect sensitive E- and F-region SPEAR-enhanced incoherent backscatter observed by the EISCAT Svalbard radar

By R. S. Dhillon, T. R. Robinson and Tim K. Yeoman


Previous studies of the aspect sensitivity of heater-enhanced incoherent radar backscatter in the high-latitude ionosphere have demonstrated the directional dependence of incoherent scatter signatures corresponding to artificially excited electrostatic waves, together with consistent field-aligned signatures that may be related to the presence of artificial field-aligned irregularities. These earlier high-latitude results have provided motivation for repeating the investigation in the different geophysical conditions that obtain in the polar cap ionosphere. The Space Plasma Exploration by Active Radar (SPEAR) facility is located within the polar cap and has provided observations of RF-enhanced ion and plasma line spectra recorded by the EISCAT Svalbard UHF incoherent scatter radar system (ESR), which is collocated with SPEAR. In this paper, we present observations of aspect sensitive E- and F-region SPEAR-induced ion and plasma line enhancements that indicate excitation of both the purely growing mode and the parametric decay instability, together with sporadic E-layer results that may indicate the presence of cavitons. We note consistent enhancements from field-aligned, vertical and also from 5° south of field-aligned. We attribute the prevalence of vertical scatter to the importance of the Spitze region, and of that from field-aligned to possible wave/irregularity coupling

Publisher: Copernicus Publications on behalf of the European Geosciences Union (EGU)
Year: 2009
DOI identifier: 10.5194/angeo-27-65-2009
OAI identifier: oai:lra.le.ac.uk:2381/8175

Suggested articles



  1. (1987). A modification event of the auroral E region as studied with EISCAT and other diagnostics, doi
  2. (1994). Altitude characteristics of plasma turbulence excited with the Tromsø superheater, doi
  3. (2005). An interferometer experiment to explore the aspect angle dependence of stimulated electromagnetic emission spectra, doi
  4. (1974). Arecibo heating experiments, doi
  5. (1999). Aspect angle dependence of HF enhanced incoherent backscatter, doi
  6. (1947). Collisional regimes of radiation-driven Langmuir turbulence, doi
  7. (2009). Dhillon et al.: Aspect sensitivity of SPEAR-enhanced incoherent backscatter doi
  8. (2009). Dhillon et al.: Aspect sensitivity of SPEAR-enhanced incoherent backscatter 81 doi
  9. (2002). Effects of multiple scatter on the propagation and absorption of electromagnetic waves in a field-aligned-striated cold magneto-plasma: implications for ionospheric modification experiments, doi
  10. (2007). EISCAT Svalbard radar observations of SPEAR-induced E- and F-region spectral enhancements in the polar cap ionosphere, doi
  11. (1999). First direct observations of the reduced striations at pump frequencies close to the electron gyroharmonics, doi
  12. (2008). First results of a ULF wave injected on open field lines by SPEAR, doi
  13. (2006). First results of artificial stimulation of the ionospheric Alfve´n resonator at 78◦ doi
  14. (1984). Frequency dependence of anomalous absorption caused by high power radio waves, doi
  15. (1977). Generation of density cavities and localized electric fields in a nonuniform plasma, doi
  16. (1977). HF excited instabilities in space plasmas, doi
  17. (2005). HF-induced airglow at magnetic zenith: theoretical considerations, doi
  18. (2002). HFpump-induced parametric instabilities in the auroral E-region, doi
  19. (1972). High frequency induced enhancements of the incoherent scatter spectrum, doi
  20. (2000). Highlatitude HF-induced airglow displaced equatorward of the pump beam, doi
  21. (1997). Initial backscatter occurrence statistics from the CUTLASS HF radars, doi
  22. (2003). Ionospheric electron heating, optical emissions, and striations induced by powerful HF radio waves at high latitudes: aspect angle dependence, doi
  23. (1979). Ionospheric modification and parametric instabilities, doi
  24. (1992). Langmuir turbulence and ionospheric modification, doi
  25. (1998). Langmuir turbulence associated with ionospheric modification: Challenges associated with recent observations during a sporadic-E event,
  26. (1978). Langmuir wave propagation and the enhanced plasma line in sporadic E, doi
  27. (1999). Large airglow enhancements produced via wave-plasma interactions in sporadic E, doi
  28. (1997). Linear mode conversion in inhomogeneous magnetized plasmas during ionospheric modification by HF radio waves, doi
  29. (2003). Magnetic zenith enhancement of HF radio-induced airglow production at HAARP, doi
  30. (2008). Mapping ionospheric backscatter measured by the SuperDARN HF radars – Part 2: Assessing SuperDARN virtual height models, doi
  31. (2000). Measurements of HF-enhanced plasma and ion lines at EISCAT with high-altitude resolution, doi
  32. (2004). Multi-frequency HF radar measurements of artificial F-region field-aligned irregularities, doi
  33. (2005). Observations of time dependence and aspect sensitivity of regions of enhanced UHF backscatter associated with RF heating, doi
  34. (2004). On the onset of HF-induced airglow at HAARP, doi
  35. (1971). On the role of plasma instabilities in ionospheric heating by radio waves, doi
  36. (1971). Parametric instabilities in inhomogeneous plasmas, doi
  37. (1972). Purely growing parametric instability in an inhomogeneous plasma, doi
  38. (2002). Radar ACFs and turbulence characteristics from artificially generated field-aligned irregularities, doi
  39. (1996). Review of ionospheric modification experiments at Tromsø, doi
  40. (2007). SPEAR: early results from a very high latitude ionospheric heating facility, doi
  41. (2002). Structure and dynamics of sporadic layers of ionization in the ionospheric E region, doi
  42. (1984). T.: HF-enhanced plasma lines in the lower ionosphere, doi
  43. (1973). Temporal evolution of a three-wave parametric instability, doi
  44. (1997). The EISCAT Svalbard radar: a case study in modern incoherent scatter radar system design, doi
  45. (1976). The excitation of plasma lines in blanketing sporadic E, doi
  46. (2000). The structure of electromagnetic wave-induced 557.7-nm emission associated with a sporadic-E event over Arecibo, doi
  47. (2003). Using radio-induced aurora to measure the horizontal structure of ion layers in the lower thermosphere, doi

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