F region behavior in the SED plume during a geomagnetic superstorm: A case study

Abstract

We report observations from the GPS total electron content (TEC), ionosonde, and Millstone Hill incoherent scatter radar showing some interesting features of the height profile of the ionospheric electron density that occurred during a passage of a stormenhanced density (SED) plume during the geomagnetic superstorm on 20 November 2003. First, the TEC increases to about 6.58 times the quiet day value, while the F peak plasma density (NmF2) only enhances by a factor of 1.37. Second, the F2 layer peak height (hmF2) is dramatically lifted from the quiet time altitude of 250 km to an unusual altitude of 577 km. Furthermore, the topside Chapman scale height HT is larger by a factor of 6.25 compared to the quiet time value. As a result, the electron density content with an α-Chapman function above 700 km contributes about 59% to the total content during the SED event. Our analysis shows that during a passage of the SED plume, the enhancement of TEC is mainly attributed to the great increase of HT with a very high hmF2. Copyright 2009 by the American Geophysical Union.