Skip to main content
Article thumbnail
Location of Repository

Observations of isolated polar cap patches by the European Incoherent Scatter (EISCAT) Svalbard and Super Dual Auroral Radar Network (SuperDARN) Finland radars

By K. Oksavik, J. M. Ruohoniemi, R. A. Greenwald, J. B. H. Baker, J. Moen, H. C. Carlson, Tim K. Yeoman and M. Lester


In this paper we present observations of the F region cusp ionosphere from the Super Dual Auroral Radar Network (SuperDARN) Finland and European Incoherent Scatter (EISCAT) Svalbard radars in a new joint experiment. On 16 December 2002 the EISCAT Svalbard radar was operated in a fast elevation scan along beam 9 of the SuperDARN Finland radar, giving altitude/latitude profiles of the SuperDARN Finland backscatter volume every 2 min. Combining the two independent data sets, we monitor an isolated polar cap patch of high electron density (1011.5 m−3) that slowly formed in the dark cusp ionosphere during an interval of northward interplanetary magnetic field. The patch formed on a stirred lobe cell, excluding the possibility for solar EUV ionized plasma to drift in from the south. This data set represents an unparalleled example of patch formation within the polar cap, locally by particle impact ionization. After the interplanetary magnetic field turned southward and By changed polarity, the patch started to move poleward into the polar cap. Enhanced velocity gave rise to enhanced HF backscatter power and enhanced spectral widths, consistent with gradient drift instability as the formation mechanism of HF backscatter targets

Publisher: American Geophysical Union (AGU)
Year: 2006
DOI identifier: 10.1029/2005JA011400
OAI identifier:

Suggested articles


  1. (1994). A new mechanism for polar patch formation, doi
  2. (2001). An evaluation of range accuracy in the Super Dual Auroral Radar Network over-the-horizon HF radar systems, doi
  3. (2000). An incoherent scatter radar technique for determining two-dimensional horizontal ionization structure in polar cap F region patches, doi
  4. andA.McWilliams (2002), Ground-based observations of the auroral zone and polar cap ionospheric responses to dayside transient reconnection, doi
  5. (2003). Continuous magnetic reconnection at Earth’s magnetopause, doi
  6. (1996). Critical review of ionospheric patches and blobs, in URSI Review of Radio Science 1993–1996, edited by
  7. (1979). Current convective instability in the diffuse aurora, doi
  8. (2002). Cusp aurora dependence on interplanetary magnetic field Bz,
  9. (2000). Dayside convection and auroral morphology during an interval of northward interplanetary magnetic field, doi
  10. (1987). Daytime F layer trough observed on a macroscopic scale, doi
  11. (1995). Direct determination of large-scale magnetospheric field-aligned currents with SuperDARN, doi
  12. (2001). EISCAT Svalbard Radar observations of ionospheric plasma dynamics in relation to dayside auroral transients, doi
  13. (2002). ESR mapping of polar-cap patches in the dark cusp, doi
  14. (2001). Excitation of transient lobe cell convection and auroral arc at the cusp poleward boundary during a transition of the interplanetary magnetic field from south to north, doi
  15. (1994). Experimental evidence for the formation and entry of patches into the polar cap, doi
  16. (1999). Global aspects of plasma structures, doi
  17. (2002). HF radar polar patch formation revisited: Summer and winter variations in dayside plasma structuring, doi
  18. (1988). High-latitude F region irregularities: A review and synthesis, doi
  19. (2004). High-resolution observations of the small-scale flow pattern associated with a poleward moving auroral form in the cusp, doi
  20. (2003). ICI-1: A new sounding rocket concept to observe micro-scale physics in the cusp ionosphere,
  21. (2004). Ionospheric patch formation: Direct measurements of the origin of a polar cap patch, doi
  22. (1998). Large-scale imaging of highlatitude convection with Super Dual Auroral Radar Network HF radar observations, doi
  23. (2003). Lobe cell convection and polar cap precipitation, doi
  24. (1974). Magnetospheric convection and the high latitude F2 ionosphere, doi
  25. (1999). Meridian-scanning photometer, coherent HF radar, and magnetometer observations of the cusp: A case study, doi
  26. (1996). Mesoscale dayside convection vortices and their relation to substorm phase, doi
  27. (1994). Modeling daytime F layer patches over Sondrestrom, Radio Sci., doi
  28. (1993). Modeling polar cap F-region patches using time varying convection, doi
  29. (1999). Modeling the ionospheric effects of ion and electron precipitation in the cusp, doi
  30. (1999). Morphology of polar-cap patch activity, doi
  31. (2005). Multi-instrument mapping of the small-scale flow dynamics related to a cusp auroral transient, doi
  32. (2002). On the generation of cusp HF backscatter irregularities, doi
  33. (1990). On the importance of ion composition to conductivities in the auroral ionosphere, doi
  34. (1999). On the possible role of cusp/cleft precipitation in the formation of polar-cap patches, doi
  35. (1988). Origin of density enhancements in the winter polar cap ionosphere, doi
  36. (1992). Production of polar cap electron density patches by transient magnetopause reconnection, doi
  37. (2002). Proton aurora in the cusp,
  38. (1984). Reinisch doi
  39. (2000). response of the cusp and cleft to IMF orientation changes, doi
  40. (2004). Seasonal dependence of localized, high-latitude dayside aurora doi
  41. (2005). Simultaneous imaging of the reconnection spot in the opposite hemispheres during northward IMF, doi
  42. (1998). Simultaneous satellite and all-sky imager observations of polar cap phenomena, doi
  43. (2004). Solar wind modulation of cusp particle signatures and their associated ionospheric flows, doi
  44. (2004). Stereo CUTLASS: A new capability for the SuperDARN radars, doi
  45. (1983). Structure and dynamics of the winter polar cap F-region, doi
  46. (1989). The daytime F layer trough and its relation to ionospheric-magnetospheric convection, doi

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