Ionospheric vertical plasma drift and electron density response during total solar eclipses at equatorial/low latitude

摘要

The response of the vertical plasma drift (V_z) and the electron density (N_mF_2) during different solar eclipses was investigated. The diurnal values of the direct scaled measurement of F_2 peak height and the one derived from M(3000) F_2 data, acquired over an equatorial/low-latitude stations, have been used to determine the vertical plasma drift. The ionosphere during a solar eclipse is significantly affected by the E × B vertical drift; the large depletion of electron density at low altitudes can be transported to high altitudes through the plasma vertical drift. The loss in ionization density during the eclipse phase decreases the electron density, which was accompanied by rapid increase in h_mF_2. This deviation in the N_mF_2 during eclipse compared to control days can be related to the increase in the loss rate due to recombination, as a result of reduction in thermal energy. However, the maximum reduction in N_mF_2 is not synchronous with the time of maximum totality but some minutes later. The differences in the solar epochs may contribute to the observed relative changes in the ionospheric F_2 region behavior during the eclipse window. Lastly, it is very difficult to separate the influence of magnetic disturbances from solar eclipse. The deviation in N_mF_2 is higher during magnetic disturbed days than the quiet day. The reverse is the case for h_mF_2 observation. However, the N_mF_2 variation increases with an increase in solar activity.