Equatorial spread F and sporadic E-layer connections during the Brazilian Conjugate Point Equatorial Experiment (COPEX)

The Conjugate Point Equatorial Experiment (COPEX) was conducted in Brazil from October to December 2002. The observational instruments were placed at three sites nearly along a magnetic meridian, one at the magnetic equator and the other two at magnetically conjugate points. We analyzed the spread F (SF) occurrence and sporadic E (Es) layer characteristics in the simultaneous data to look for any possible relation between these two phenomena. The present study does not detect any significant correlation between the SF occurrence/generation at the magnetic equator and the presence of Es layers at the conjugate E regions along the same field line. The integrated field line conductivity is not significantly affected by the occurrence of Es at the conjugate E regions and its presence is not sufficient to inhibit the vertical drift and SF generation at the magnetic equator. Model results show that the presence of a vertical equatorial electric field (associated with the eastward electric field pre-reversal enhancement) is too week to affect the Es development at the conjugate stations.