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Full-Text Articles in Physics
Ionospheric Response To An Auroral Substorm, Robert W. Schunk, L. Zhu, Jan Josef Sojka, M. D. Bowline
Ionospheric Response To An Auroral Substorm, Robert W. Schunk, L. Zhu, Jan Josef Sojka, M. D. Bowline
All Physics Faculty Publications
The response of the ionosphere to a representative auroral substorm was simulated. The response was found to be significant at all altitudes in a large spatial region near midnight magnetic local time. In this midnight region, there were Te and Ti hot spots, substantial O+ → NO+ composition changes, non‐Maxwellian velocity distributions, transient ion upwellings, a large‐scale lowering of the F‐layer, ionization peaks that occur in the E‐region, and sharp horizontal gradients. Also, during the expansion phase, the E‐region densities increase due to auroral precipitation, while the plasma densities above 300 km decrease due to the …
Ionospheric Response To The Sustained High Geomagnetic Activity During The March '89 Great Storm, Jan Josef Sojka, Robert W. Schunk, W. F. Denig
Ionospheric Response To The Sustained High Geomagnetic Activity During The March '89 Great Storm, Jan Josef Sojka, Robert W. Schunk, W. F. Denig
All Physics Faculty Publications
A simulation was conducted to model the high-latitude ionospheric response to the sustained level of high geomagnetic activity for the great magnetic storm period of March 13-14, 1989. The geomagnetic and solar activity indices and the DMSP F8 and F9 satellite data for particle precipitation and high-latitude convection were used as inputs to a time-dependent ionospheric model (TDIM). The results of the TDIM were compared to both DMSP plasma density data and ground-based total electron content (TEC) measurements for the great storm period as well as with earlier storm observations. The comparisons showed that the overall structure of the high-latitude …
Ionospheric Response To Traveling Convection Twin Vortices, Robert W. Schunk, Lie Zhu, Jan Josef Sojka
Ionospheric Response To Traveling Convection Twin Vortices, Robert W. Schunk, Lie Zhu, Jan Josef Sojka
All Physics Faculty Publications
Traveling convection twin vortices have been observed for several years. At ionospheric altitudes, the twin vortices correspond to spatially localized, transient structures embedded in a large‐scale background convection pattern. The convection vortices are typically observed in the morning and evening regions. They are aligned predominantly in the east‐west direction and have a horizontal extent of from 500–1000 km. Associated with the twin vortices are enhanced electric fields, particle precipitation, and an upward/downward field‐aligned current pair. Once formed, the twin vortex structures propagate in the tailward direction at speeds of several km/s, but they weaken as they propagate and only last …