Effects of intense magnetic storms on the low latitude ionosphere / Efeito das tempestades magneticas intensas na ionosfera de baixa latitude

AUTOR(ES)
DATA DE PUBLICAÇÃO

2000

RESUMO

The objective of this dissertation is to study the magnetic storm effects on the ionospheric F region over the equatorial region (Fortaleza)and the low-latitude region (Cachoeira Paulista), in Brazil. This research subject is relatively new and of interest to the international scientific community. It is a complex topic since it comprises an assortment of coupled variations of physical parameters of the ionosphere/ thermosphere/magnetosphere system. During the magnetic storms, which is defined as a large negative excursion in the magnitude of the Dst index, the ionosphere undergoes substantial perturbations in a global level. The main ionospheric effects focused here are: 1)zonal electric field penetration (east-west direction)stemming from the auroral region into the low and equatorial latitude regions; 2)effects of disturbed thermospheric winds (Disturbance Dynamo). The methodology adopted here to study magnetic storms effects in the ionosphere consists basically on the comparison of quiet and disturbed ionospheric parameters. For the quiet behavior we have used the average values of several quiet days taken in a time interval of ñ 15 days around the beginning of the magnetic storm. Our results show intense F region height (h F and hpF2)drifts and critical frequency (foF2)variations that are here discussed in the light of the storm parameters such as the auroral index AE, the north-south component of the interplanetary magnetic field Bz (as obtained by the ISEE3 satellite)and the Dst index.

ASSUNTO(S)

sondagem ionosfericas tempestades magneticas ionossonda espalhamento distirbio ionosfericos disturbios ionosfericos suditos deriva ionosferica geofisica espacial

ACESSO AO ARTIGO

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