March 12, 2010, 12:00 pm - 1:00 pm

March 12, 2010, 12:00 pm - 1:00 pm

The properties and 3D structure of medium scale traveling ionospheric disturbances

Ilgin Seker (NASA Postdoctroral Fellow, Geospace Physics Laboratory, GSFC)

One of the most prominent of the mid-latitude ionospheric phenomena is the Medium-Scale Traveling Ionospheric Disturbances (MSTIDs) in the F-region that usually occur when the geomagnetic activity is low. These MSTIDs with 100-300 km horizontal wavelength and ~1 hr period have been also called as plasma depletion bands, plasma bubbles, ionospheric slabs, and thermospheric waves. Using a combination of instruments to simultaneously observe these MSTIDs proves to be useful. In particular, allsky images provide the horizontal information complement to the narrow-beam Incoherent Scatter Radar (ISR) vertical profiles. A 3D empirical model of these bands was developed based on a specific observational technique that combines the ISR and allsky imager observations over the Arecibo Observatory (AO) in Puerto Rico. The model is intended to replicate both the ISR and the allsky imager results, and is especially useful in explaining how these structures appear in the complex azimuth-scanning ISR results. In particular, this study has shown for the first time that the southern part of an MSTID band reaches higher altitudes than its northern part implying that the MSTID bands are vertically tilted. In addition, the results of the empirical model provide clues on what to expect from the theoretical models of MSTIDs. Finally, this technique is not limited to F-region or mid-latitudes only; it can be applied to any other ionospheric phenomenon that is observed by both radar and imager.