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Polar cap patches and the tongue of ionization: A survey of GPS TEC maps from 2009 to 2015
Author(s) -
David Michael,
Sojka J. J.,
Schunk R. W.,
Coster A. J.
Publication year - 2016
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2016gl068136
Subject(s) - tec , polar cap , polar , flux (metallurgy) , northern hemisphere , atmospheric sciences , ionosphere , ionization , precipitation , physics , geology , geophysics , meteorology , astronomy , chemistry , ion , organic chemistry , quantum mechanics
The source and structuring mechanisms for F region density patches have been subjects of speculation and debate for many years. We have made a survey of mappings of total electron content (TEC) between the years 2009 and 2015 from the web‐based Madrigal data server in order to determine when patches and/or a tongue of ionization (TOI) have been present in the Northern Hemisphere polar cap; we find that there is a UT and seasonal dependence that follows a specific pattern. This finding sheds considerable light upon the old question of the source of polar cap patches, since it virtually eliminates potential patch plasma sources that do not have a UT/seasonal dependence, for example, particle precipitation or flux transfer events. We also find that the frequency of occurrence of patches or TOIs has little to do with the level of geomagnetic activity.