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New Dynamic Aspects of Intertropical F 2 Ionization
Author(s) -
Vila Paul
Publication year - 1971
Publication title -
radio science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.371
H-Index - 84
eISSN - 1944-799X
pISSN - 0048-6604
DOI - 10.1029/rs006i011p00945
Subject(s) - physics , atmospheric sciences , asymmetry , ionization , local time , atomic physics , ion , statistics , mathematics , quantum mechanics
Diurnal changes in F 2 ionization distribution as measured during June and July 1966 over the Tamanrasset meridian reveal two types of asymmetric phenomena distorting the crest‐and‐trough system (formerly known as the equatorial F 2 ionization anomaly). The first type corresponds to a general time variation of the latitude asymmetry. Our observations yield four independent parameters of this asymmetry; for 80% of the time, the variation can be attributed to ion drag due to a time‐varying meridian air wind. Magnetic activity is correlated with the amplitude of this wind, and the low‐altitude thermospheric circulation is discussed. Day‐to‐day fluctuations of the diurnal evolution pattern suggest a possible long‐term control of the equatorial electric field by the general dynamo current system. A second type of asymmetry shows more intense, local, and short‐lived phases superimposed on the fountain and neutral wind fluctuations. It has the character of a transitory forced‐diffusion process. We believe that the factor responsible is electron temperature gradients produced by conjugate photoelectron heating.