Magnetic effects during the solar eclipse of July 11, 1991

Abstract

During the total solar eclipse of July 11, 1991 magnetic observations were conducted at three stations in Mexico. A very clear signature of the eclipse effect is present in the horizontal component H, as well as in total intensity F. Declination and vertical component show a small effect and nothing is noted in magnetic inclination I. The F observations from all stations arc very similar. The eclipse effect profile resembles the foE and N(h) changes reported several times in the literature. A possible linear relation between the ionospheric and magnetic effects is suggested. It is also proposed that simultaneous observations of X-Ray sources on the Sun, ionospheric parameters and surface magnetic field changes must be conducted during next eclipses to establish more clearly its relationships. Furthermore, a revision of the theoretical basis of the generation of the magnetic effect must be made in order to explain the observations.