Ion convection and the formation of the mid‐latitude F region ionization trough

Measurements of total ion concentration and ion drift velocity from Atmosphere Exlorer C have been used to examine the convective flow of plasma in the vicinity of the mid-latitude F region ionization trough. It is found that the low-latitude portion of the premidnight trough is a region of slow eastward plasma drfit while the poleward portion is characterized by generally westward flow. The reversal from eastward to westward flow typically occurs on the low-latitude edge of the trough where N/sub 1/ is observed to vary smoothly. We propose that the plasma flux tubes within the premidnight trough have corotated eastward into the evening local time sector from dusk before stagnating and flowing westward at higher latitudes in the nighttime sector. In the absence of ionization sources, rather deep troughs can be formed by F region recombination during the long time required for the flow to stagnate and reverse. The proposed drift paths can result quite naturally from the combined effects of the corotation and magnetospheric electric fields. Large plasma convection velocities that act to increase the F region decay rate are not required to produce a trough but may cause the plasma composition changes that are occasionally observed within themore » trough.« less

[1]  D. Stern.  Large-scale electric fields in the Earth's magnetosphere , 1977 .

[2]  J. Heppner.  Empirical models of high latitude electric fields , 1977 .

[3]  D. Albritton,et al.  Effects of ion speed distributions in flow‐drift tube studies of ion–neutral reactions , 1977 .

[4]  J. Grebowsky,et al.  The plasmapause revisited , 1976 .

[5]  R. Heelis,et al.  Ion convection velocity reversals in the dayside cleft , 1976 .

[6]  R. Schunk,et al.  Effects of electric fields and other processes upon the nighttime high-latitude F layer , 1976 .

[7]  R. Heelis,et al.  Techniques for measuring bulk gas-motions from satellites , 1975 .

[8]  R. Schunk,et al.  Effect of electric fields on the daytime high-latitude E and F regions , 1975 .

[9]  R. Schunk,et al.  NO/+/ and O/+/ in the high latitude F-region , 1974 .

[10]  H. Volland.  Models of global electric fields within the magnetosphere , 1974 .

[11]  Y. Tulunay,et al.  Temporal variations in the dawn and dusk midlatitude trough and plasmapause position , 1974 .

[12]  W. C. Knudsen,et al.  Magnetospheric convection and the high‐latitude F 2 ionosphere , 1974 .

[13]  N. Maynard,et al.  Electric field measurements across the harang discontinuity. [of the auroral zone , 1974 .

[14]  D. Albritton,et al.  Flow‐drift technique for ion mobility and ion‐molecule reaction rate constant measurements. II. Positive ion reactions of N+, O+, and H2+ with O2 and O+ with N2 from thermal to [inverted lazy s]2 eV , 1973 .

[15]  J. Heppner.  High latitude electric fields and the modulations related to interplanetary magnetic field parameters , 1973 .

[16]  R. Horan,et al.  HILION - A Model of the High-Latitude Ionospheric F2 Layer and Statistics of Regular Ionospheric Effects at Ft. Churchill, 1968, , 1973 .

[17]  Richard A. Wolf,et al.  Self‐consistent calculation of the motion of a sheet of ions in the magnetosphere , 1973 .

[18]  W. B. Hanson,et al.  The retarding-potential analyzer on Atmosphere Explorer , 1973 .

[19]  N. Spencer,et al.  The Atmosphere Explorer spacecraft system , 1973 .

[20]  N. Spencer,et al.  The Atmosphere Explorer mission. , 1973 .

[21]  R. Hunsucker,et al.  Aurora and the poleward edge of the main ionospheric trough , 1973 .

[22]  D. Gurnett,et al.  Satellite measurements of high latitude convection electric fields , 1972 .

[23]  Y. Tulunay,et al.  Characteristics of the mid-latitude trough as determined by the electron density experiment on Ariel III , 1971 .

[24]  N. Miller.  The main electron trough during the rising solar cycle , 1970 .

[25]  A. J. Chen,et al.  Plasma flow in the magnetosphere. , 1968 .

[26]  G. W. Sharp.  Midlatitude trough in the night ionosphere , 1966 .

[27]  D. B. Muldrew,et al.  F‐layer ionization troughs deduced from Alouette data , 1965 .

[28]  C. O. Hines,et al.  A UNIFYING THEORY OF HIGH-LATITUDE GEOPHYSICAL PHENOMENA AND GEOMAGNETIC STORMS , 1961 .

[29]  M. Rycroft,et al.  The magnetospheric plasmapause and the electron density trough at the Alouette I orbit , 1970 .

[30]  Henry Rishbeth,et al.  Introduction to ionospheric physics , 1969 .