Location of Repository

High resolution observations of spectral width features associated with ULF wave signatures in artificial HF radar backscatter

By D. M. Wright, Tim K. Yeoman, L. J. Baddeley, J. A. Davies, R. Dhillon, M. Lester, Steve E. Milan and E. E. Woodfield


The EISCAT high power heating facility at Tromsø, northern Norway, has been utilised to generate artificial radar backscatter in the fields of view of the CUTLASS HF radars. It has been demonstrated that this technique offers a means of making very accurate and high resolution observations of naturally occurring ULF waves. During such experiments, the usually narrow radar spectral widths associated with artificial irregularities increase at times when small scale-sized (high m-number) ULF waves are observed. Possible mechanisms by which these particle-driven high-m waves may modify the observed spectral widths have been investigated. The results are found to be consistent with Pc1 (ion-cyclotron) wave activity, causing aliasing of the radar spectra, in agreement with previous modelling work. The observations also support recent suggestions that Pc1 waves may be modulated by the action of longer period ULF standing waves, which are simultaneously detected on the magnetospheric field lines. Drifting ring current protons with energies of ∼ 10keV are indicated as a common plasma source population for both wave types

Topics: Magnetospheric physics (MHD waves and instabilities), Space plasma physics (wave-particle interactions), Ionosphere (active experiments)
Publisher: European Geosciences Union (EGU), Copernicus Publications, Springer Verlag (Germany)
Year: 2004
DOI identifier: 10.5194/angeo-22-169-2004
OAI identifier: oai:lra.le.ac.uk:2381/712

Suggested articles



  1. (2001). A case study of HF radar spectra and 630.0 nm auroral emission in the pre midnight sector, doi
  2. (1999). A modulated multiband Pc1 event observed by Polar/EFI around the plasmapause, doi
  3. (1989). A review on radio studies of auroral E-region ionospheric irregularities,
  4. (1991). Auroral plasma waves, in: Auroral Physics, edited by doi
  5. (1979). Current convective instability in the diffuse aurora, doi
  6. (1999). CUTLASS observations of a high-m ULF wave and its consequences for the DOPE HF Doppler sounder, doi
  7. (1995). Cyclotron instabilities and electromagnetic emission in the ultra low frequency and very low frequency ranges, doi
  8. (1995). DARN/SuperDARN: a global view of the dynamics of highlatitude convection, doi
  9. DE-2 cusp observations: role of plasma instabilities in topside ionospheric heating and density fluctuations, doi
  10. (1976). Ducted propagation of hydromagnetic waves in the upper ionosphere, doi
  11. (2001). Ground-based and Polar spacecraft observations of a giant (Pg) pulsation and its associated source mechanism, doi
  12. (1989). Ground-satellite study of a Pc 1 ion cyclotron wave event, doi
  13. (1987). HF radar observations of E-region plasma irregularities produced by oblique electron streaming, doi
  14. (2002). High and variable spectral width in the pre-dawn sector: A case study involving CUTLASS, EISCAT, ESR and optical data,
  15. (1999). High resolution bistatic HF radar observations of ULF waves in artificially generated backscatter, doi
  16. (1997). High spatial and temporal resolution observations of an impulse-driven field line resonance in radar backscatter artificially generated with the Tromsø heater, doi
  17. (1995). High spatial and temporal resolution observations of the ionospheric cusp, doi
  18. (1983). Hydromagnetic waves in the magnetosphere, in: Solar Terrestrial Physics, edited by doi
  19. (1965). Hydromagnetic whistlers, doi
  20. (1997). Initial backscatter occurrence statistics from the CUTLASS HF radars, doi
  21. (2001). Interhemispheric differences in the HF radar signature of the cusp region. A review through the study of a case example, Adv. in Polar Upper Atmos.
  22. (1998). Introduction to ionospheric heating at Tromsø – I. Experimental overview, doi
  23. (1966). Limit on stably trapped particle fluxes, doi
  24. (1975). Locating the Pc1 generation region by a statistical analysis of ground-based observations, doi
  25. (1983). Microscopic plasma processes in the Jovian magnetosphere, in: Physics of the Jovian magnetosphere, edited by Dessler, doi
  26. (1999). New electron gyroharmonic effects in HF scatter from pump-excited magnetic field-aligned ionospheric irregularities, doi
  27. (1991). Nonbouncing Pc1 wave bursts,
  28. (1997). O- and X-mode heating effects observed simultaneously with the CUTLASS and EISCAT radars and low power HF diagnostics at Tromsø,
  29. (1996). Observation of the high latitude ionosphere by HF radars: Interpretation in terms of collective wave scattering and characterization of turbu182 doi
  30. On the factors conditioning the Doppler spectral width determined from SuperDARN HF radars, doi
  31. (1999). On the SuperDARN autocorrelation function observed in the ionospheric cusp, doi
  32. (1996). Pc 1-2 and Pc 4-5 pulsations observed at a network of high-latitude stations, doi
  33. (2001). Pc1 pearls revisited: structured electromagnetic ion cyclotron waves on Polar satellite and on ground, doi
  34. (1990). Simultaneous HF-radar and DMSP observations of the cusp, doi
  35. (2000). Space Plasma Exploration by Active Radar (SPEAR): an overview of a future radar facility, doi
  36. (2002). Spectral width features associated with ULF wave signatures in artificial HF radar backscatter 181 doi
  37. (1991). Statistical study of highlatitude E-region Doppler spectra obtained with the SHERPA HF radar,
  38. (1972). Stormtime instabilities in the ring current, in: Magnetosphere ionosphere interactions, edited by Folkestad,
  39. (1985). Structure in the DC and AC electric fields associated with the dayside cusp region, in: The polar cusp, edited by doi
  40. (1989). The heating of the high latitude ionosphere by high power radio waves, doi
  41. (1980). The horizontal propagation of doi
  42. (2002). The role of Pc1-2 waves in spectral broadening of SuperDARN echoes from high latitudes, doi
  43. (1976). The screening of micropulsation signals by the atmosphere and ionosphere, doi
  44. (1990). Theory of electromagnetic cyclotron wave growth in a time-varying magnetoplasma, doi
  45. (2001). ULF waves with drift resonance and drift-bounce resonance energy sources as observed in artificially-induced HF radar backscatter, doi

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