Geomagnetically conjugate observation of plasma bubbles and thermospheric neutral winds at low latitudes

• Main Authors: Fukushima D., Shiokawa K., Otsuka Y., Nishioka M., Kubota M., Tsugawa T., Nagatsuma T., Komonjinda S., Yatini C.
• Format: Article
• Published: American Geophysical Union 2015
• Subjects: Oceanography; Ecology; Soil Science; Earth and Planetary Sciences (miscellaneous); Forestry; Atmospheric Science; Aquatic Science; Earth-Surface Processes; Water Science and Technology; Geochemistry and Petrology; Paleontology; Space and Planetary Science; Geophysics
• Online Access: http://www.scopus.com/inward/record.url?partnerID=HzOxMe3b&scp=84927732337&origin=inward; http://cmuir.cmu.ac.th/handle/6653943832/38925
• Institution: Chiang Mai University

©2015. American Geophysical Union. All Rights Reserved. This is the first paper that reports simultaneous observations of zonal drift of plasma bubbles and the thermospheric neutral winds at geomagnetically conjugate points in both hemispheres. The plasma bubbles were observed in the 630 nm nighttime airglow images taken by using highly sensitive all-sky airglow imagers at Kototabang, Indonesia (geomagnetic latitude (MLAT): 10.0S), and Chiang Mai, Thailand (MLAT: 8.9N), which are nearly geomagnetically conjugate stations, for 7 h from 13 to 20 UT (from 20 to 03 LT) on 5 April 2011. The bubbles continuously propagated eastward with velocities of 100-125 m/s. The 630 nm images at Chiang Mai and those mapped to the conjugate point of Kototabang fit very well, which indicates that the observed plasma bubbles were geomagnetically connected. The eastward thermospheric neutral winds measured by two Fabry-Perot interferometers were 70-130 m/s at Kototabang and 50-90 m/s at Chiang Mai. We compared the observed plasma bubble drift velocity with the velocity calculated from the observed neutral winds and the model conductivity, to investigate the F region dynamo contribution to the bubble drift velocity. The estimated drift velocities were 60-90% of the observed velocities of the plasma bubbles, suggesting that most of the plasma bubble velocity can be explained by the F region dynamo effect.