Journal cover Journal topic
Annales Geophysicae An interactive open-access journal of the European Geosciences Union
Journal topic

Journal metrics

Journal metrics

  • IF value: 1.490 IF 1.490
  • IF 5-year value: 1.445 IF 5-year
    1.445
  • CiteScore value: 2.9 CiteScore
    2.9
  • SNIP value: 0.789 SNIP 0.789
  • IPP value: 1.48 IPP 1.48
  • SJR value: 0.74 SJR 0.74
  • Scimago H <br class='hide-on-tablet hide-on-mobile'>index value: 88 Scimago H
    index 88
  • h5-index value: 21 h5-index 21
Volume 22, issue 4
Ann. Geophys., 22, 1149–1153, 2004
https://doi.org/10.5194/angeo-22-1149-2004
© Author(s) 2004. This work is distributed under
the Creative Commons Attribution 3.0 License.
Ann. Geophys., 22, 1149–1153, 2004
https://doi.org/10.5194/angeo-22-1149-2004
© Author(s) 2004. This work is distributed under
the Creative Commons Attribution 3.0 License.

  02 Apr 2004

02 Apr 2004

Velocity shear-related ion upflow in the low-altitude ionosphere

H. Liu1 and G. Lu2 H. Liu and G. Lu
  • 1GeoForschungsZentrum Potsdam, Telegrafenberg, Potsdam, Germany
  • 2High Altitude Observatory, NCAR, Boulder, CO, USA

Abstract. Strong ion upflows with field-aligned velocity above 1000ms were observed by the European Incoherent Scatter (EISCAT) UHF Radar at Tromsø, Norway in the dayside auroral region at heights between 500–600km during the 15 May 1997 magnetic storm. Both the EISCAT observations and the Assimilative Mapping of Ionospheric Electrodynamics (AMIE) simulation results show that this event occurred in a region with low Joule heating rate, but with strong velocity shear. During the same period, the electron density and temperature showed no sign of soft particle precipitation, which is consistent with the UVI images from the POLAR satellite, thus excluding possible ion energization through soft particle precipitation. Our simple calculation shows that the velocity shear can provide sufficient energy for the observed ion upflow, thus suggesting shear-driven instabilities as a possible heating mechanism.

Key words. Ionosphere, particle acceleration, magnetospheric physics

Publications Copernicus
Download
Citation