Alicia Favetto

Currents induced by geomagnetic storms on buried pipelines as a cause of corrosion

Protection of buried pipelines from corrosion constitutes an important objective to be taken into account in the design of pipelines networks. Most of the destructive processes which affect metals are of an electrochemical nature, mainly associated with the characteristics of the soils where they are buried. Protection methods usually involve the application of a non-corrosive coating over the pipes together with cathodic protection, which prevent the flow of ionic currents from the pipe to its surrounding soil. Nevertheless, these methods do not always compensate for the pipeline corrosion effects. In particular, during days of high geomagnetic activity and depending on the electrical conductivity of the host soil, excessive induced currents are channeled along the pipes which can override the protection measures. Within this framework, we present a study of electromagnetic induction in buried pipelines, assuming that geomagnetic storms are the external source responsible for the erratic currents. Our aim is to quantify the induction as a function of the characteristic of the soils and of the frequency and intensity of the inducing field in order to contribute to better understand and improve the pipeline corrosion protective methods. The results of our study indicate that geomagnetic effects can introduce significant disturbances on buried pipelines, increasing their risk of corrosion and potentially reducing their safe useful life.

Solar quiet geomagnetic variations and E-region neutral winds at equatorial latitudes

Abstract A model of the ionospheric current system valid at zones close to the geomagnetic equator, taking into account the contribution of neutral winds, is proposed. From this, the external magnetic field at ground is calculated. Also, ground records of the geomagnetic field variations at the Peruvian equatorial zone were separated into their external and internal contributions. Using an iterative process a local particular fitting was found by comparing the separated external field to the one calculated with the proposed model.