Source Region and Propagation of Dayside Large‐Scale Traveling Ionospheric Disturbances. Issue 19 (25th September 2020)

• Record Type: Journal Article
• Authors: Nishimura, Y.; Zhang, S. R.; Lyons, L. R.; Deng, Y.; Coster, A. J.; Moen, J. I.; Clausen, L. B.; Bristow, W. A.; Nishitani, N.
• Is Part Of: Geophysical research letters. Volume 47:Issue 19(2020)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-09-25
• Subjects: LSTID -- GNSS, GPS, and GLONASS -- all‐sky imager -- DMSP -- SuperDARN -- MMS; Geophysics -- Periodicals; Planets -- Periodicals; Lunar geology -- Periodicals; 550
• DOI: 10.1029/2020GL089451
• Languages: English
• ISSNs: 0094-8276

Abstract

Abstract: We examined the source region of dayside large‐scale traveling ionospheric disturbances (LSTIDs) and their relation to cusp energy input. Aurora and total electron content (TEC) observations show that LSTIDs propagate equatorward away from the cusp and demonstrate the cusp region as the source region. Enhanced energy input to the cusp initiated by interplanetary magnetic field (IMF) southward turning triggers the LSTIDs, and each LSTID oscillation is correlated with a TEC enhancement in the dayside oval with tens of minutes periodicity. Equatorward‐propagating LSTIDs are likely gravity waves caused by repetitive heating in the cusp. The cusp source can explain the high LSTID occurrence on the dayside during geomagnetically active times. Poleward‐propagating ΔTEC patterns in the polar cap propagate nearly at the convection speed. While they have similar ΔTEC signatures to gravity wave‐driven LSTIDs, they are suggested to be weak polar cap patches quasiperiodically drifting from the cusp into the polar cap via dayside reconnection. Key Points: The cusp region in the dayside auroral oval has been found to be the source region of dayside LSTIDs Enhanced energy input to the cusp initiated by IMF southward turning triggers the dayside LSTIDs Midlatitude LSTIDs are thermospheric gravity waves; polar cap TEC perturbations are weak polar cap patches