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Thermal ion upflow in the cusp ionosphere and its dependence on soft electron energy flux

By J. K. Burchill, D. J. Knudsen, J. H. Clemmons, K. Oksavik, R. F. Pfaff, C. T. Steigies, A. W. Yau and Tim K. Yeoman


We investigate the origin of low-energy (Ek < 10 eV) ion upflows in Earth's low-altitude dayside cusp region. The Cusp-2002 sounding rocket flew from Ny Ålesund, Svalbard, on 14 December 2002, carrying plasma and field instrumentation to an altitude of 768 km. The Suprathermal Ion Imager, a two-dimensional energy/arrival angle spectrograph, observed large (>500 m s−1) ion upflows within the cusp at altitudes between 640 km and 768 km. We report a significant correlation between ion upflow and precipitating magnetosheath electron energy flux in this altitude range. There is only very weak correlation between upflow and wave power in the VLF band. We find a small negative correlation between upflow and the magnitude of the DC electric field for fields less than about 70 mV m−1. The apparent relation between upflow and electron energy flux suggests a mechanism whereby ions are accelerated by parallel electric fields that are established by the soft electrons. Significant ion upflows are not observed for electron energy fluxes less than about 1010 eV cm−2 s−1. The lack of correspondence between ∣E∣ and upflow on the one hand, and wave power and upflow on the other, does not rule out these processes but implies that, if operating, they are not local to the measurement region. We also observe narrow regions of large ion downflow that imply either a rebalancing of the ionosphere toward a low-Te equilibrium during which gravity dominates over the pressure gradients or a convection of the upflowing ions away from the precipitation region, outside of which the ions must fall back into equilibrium at lower altitudes

Publisher: American Geophysical Union (AGU)
Year: 2010
DOI identifier: 10.1029/2009JA015006
OAI identifier: oai:lra.le.ac.uk:2381/8216

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  2. (1991). A morphological study of vertical ionospheric flows in the high‐latitude F region, doi
  3. (1994). A time‐dependent gyro‐kinetic model of thermal ion upflows in the high‐latitude F region, doi
  4. (1982). An instrument for rapidly measuring plasma distribution functions with high resolution, doi
  5. (2007). Auroral ion outflow: Low altitude energization, doi
  6. (2009). Characteristics of ion upflow and downflow observed with the European Incoherent Scatter Svalbard radar, doi
  7. (2004). Core ion interactions with BB ELF, lower hybrid, and Alfvén waves in the high‐latitude topside ionosphere, doi
  8. (1998). Correlation between core ion energization, suprathermal electron bursts, and broadband ELF plasma waves, doi
  9. (1994). Coupling of microprocesses and macroprocesses due to velocity shear: An application to the low‐altitude ionosphere, doi
  10. (1989). Dayside observations of thermal‐ion upwellings at 800‐km altitude: An ionospheric signature of the cleft ion fountain, doi
  11. (2007). Demeter high resolution observations of the ionospheric thermal plasma response to magnetospheric energy input during the magnetic storm of doi
  12. (1995). Effects of frictional ion heating and soft‐electron precipitation on high‐latitude F‐region upflows, doi
  13. (1989). EISCAT observations of strong ion outflows from the F‐region ionosphere during auroral activity: Preliminary results, doi
  14. (1992). EISCAT observations of topside ionospheric ion outflows during auroral activity: Revisited, doi
  15. Elphic (2005), Factors controlling ionospheric outflows as observed at intermediate altitudes, doi
  16. (1985). Escape of suprathermal O+ ions in the polar cap, doi
  17. (1993). EXOS D (Akebono) suprathermal mass spectrometer observations of the polar wind, doi
  18. (1998). FAST observations in the downward auroral current region: Energetic upgoing electron beams, parallel potential drops, and ion heating, doi
  19. (1966). Formation of plasmapause, or magnetospheric plasma knee, by the combined action of magnetospheric convection and plasma escape from the tail, doi
  20. (1997). Four contemporary issues concerning ionospheric plasma flow to the magnetosphere, Space Sci. doi
  21. (1969). High‐latitude plasma transport: The polar wind, doi
  22. (2003). High‐resolution observations of core and suprathermal ions in the auroral ionosphere: Techniques and results from the GEODESIC sounding rocket,
  23. (1996). In situ generation of intense parallel electric fields in the lower ionosphere, doi
  24. (1998). Ion energization mechanisms at 1700 km in the auroral region, doi
  25. (2002). Ion outflow and associated perpendicular heating in the cusp observed by Interball Auroral Probe and Fast Auroral Snapshot, doi
  26. (2003). Ion upflow enhanced by drifting F‐region plasma structure along the nightside polar cap boundary, doi
  27. (1980). Light ion concentrations and fluxes in the polar regions during magnetically quiet times, doi
  28. (1998). Measurements of thermal ion drift velocity and temperature using planar sensors, in Measurement Techniques in Space Plasmas: Particles, doi
  29. (1980). Modulation of terrestrial ion escape flux composition (by low‐altitude acceleration and charge exchange chemistry), doi
  30. (1977). Observation of an ionospheric acceleration mechanism producing energetic keV ions primarily normal to the geomagnetic field direction, doi
  31. (1975). Observations of an intense field‐aligned thermal ion flow and associated intense narrow band electric field oscillations, doi
  32. (2004). On the relationship between ion upflow events and cusp auroral transients, doi
  33. (2005). Origin of type‐2 thermal‐ion upflows in the auroral ionosphere, doi
  34. (1986). Parallel acceleration and transport of ions from polar ionosphere to plasma sheet, doi
  35. (2005). Polar study of ionospheric ion outflow versus energy input, doi
  36. (2009). Rocket‐based measurements of ion velocity, neutral wind, and electric field in the collisional transition region of the auroral ionosphere, doi
  37. (1972). Satellite observations of energetic heavy ions during a geomagnetic storm, doi
  38. (2007). SERSIO: Svalbard EISCAT rocket study of ion outflows, doi
  39. (2000). Simultaneous EISCAT Svalbard and VHF radar observations of ion upflows at different aspect angles, doi
  40. (1999). Source processes in the high‐latitude ionosphere, doi
  41. (1997). Sources of ion outflow in the high latitude ionosphere, Space Sci. doi
  42. (1997). Statistical relationships between high‐latitude ionospheric F region/topside upflows and their drivers: doi
  43. (2004). Stereo CUTLASS: A new capability for the SuperDARN HF radars, doi
  44. (1990). Storm time heavy ion outflow at mid‐latitude, doi
  45. (2005). Surface property effects on Langmuir probes launched on sounding rockets,
  46. (1985). The cleft ion fountain, doi
  47. (1981). The distribution of ion beams and conics below 8000 km, doi
  48. (1982). The ionosphere as a source for magnetospheric ions, doi
  49. (1978). The latitudinal, diurnal, and altitudinal distributions of upward flowing energetic ions of ionospheric origin, doi
  50. (1982). The polar ionosphere as a source of energetic magnetospheric plasma, doi
  51. (2007). The polar wind: Recent observations, doi
  52. (2001). The relationship between suprathermal heavy ion outflow and auroral electron energy deposition: Polar/Ultraviolet Imager and Fast Auroral Snapshot/ Time‐of‐Flight Energy Angle Mass Spectrometer observations, doi
  53. (1988). The terrestrial plasma source: A new perspective in solar‐terrestrial processes from Dynamics Explorer, doi
  54. (1977). The transient response of the topside ionosphere to precipitation, doi
  55. (1984). Thermospheric control of the auroral source of O+ ions for the magnetosphere, doi
  56. (2008). Thermospheric density in the Earth’s magnetic cusp as observed by the Streak mission, doi
  57. (2004). Thermospheric up‐welling in the cusp region: doi

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