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Variability of Thermosphere and Ionosphere Responses to Solar FlaresWe investigated how the rise rate and decay rate of solar flares affect the thermosphere and ionosphere responses to them. Model simulations and data analysis were conducted for two flares of similar magnitude (X6.2 and X5.4) that had the same location on the solar limb, but the X6.2 flare had longer rise and decay times. Simulated total electron content (TEC) enhancements from the X6.2 and X5.4 flares were 6 total electron content units (TECU) and approximately 2 TECU, and the simulated neutral density enhancements were approximately 15% -20% and approximately 5%, respectively, in reasonable agreement with observations. Additional model simulations showed that for idealized flares with the same magnitude and location, the thermosphere and ionosphere responses changed significantly as a function of rise and decay rates. The Neupert Effect, which predicts that a faster flare rise rate leads to a larger EUV enhancement during the impulsive phase, caused a larger maximum ion production enhancement. In addition, model simulations showed that increased E x B plasma transport due to conductivity increases during the flares caused a significant equatorial anomaly feature in the electron density enhancement in the F region but a relatively weaker equatorial anomaly feature in TEC enhancement, owing to dominant contributions by photochemical production and loss processes. The latitude dependence of the thermosphere response correlated well with the solar zenith angle effect, whereas the latitude dependence of the ionosphere response was more complex, owing to plasma transport and the winter anomaly.
Document ID
20120011919
Acquisition Source
Goddard Space Flight Center
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Qian, Liying
(National Center for Atmospheric Research Boulder, CO, United States)
Burns, Alan G.
(National Center for Atmospheric Research Boulder, CO, United States)
Chamberlin, Philip C.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Solomon, Stanley C.
(National Center for Atmospheric Research Boulder, CO, United States)
Date Acquired
August 26, 2013
Publication Date
October 1, 2011
Publication Information
Publication: Journal of Geophysical Research
Volume: 116
Subject Category
Geophysics
Report/Patent Number
GSFC.JA.01155.2012
Funding Number(s)
CONTRACT_GRANT: NNX08AQ31G
CONTRACT_GRANT: NNX09AJ60G
Distribution Limits
Public
Copyright
Other

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