Ondas de Alfvén no meio interplanetário

Abstract

Alfvén waves are transversal waves that propagate along magnetic field lines. They can be generated in any fluid able to conduct electricity and in the presence of a magnetic field. The waves were matematically discovered in 1942 by Hannes Alfvén using electromagnetic and hidrodinamic equations. Experimental confirmation of their existence took place seven years later by investigations about waves in liquid mercury. It is known that these waves are an important mechanism of energy and momentum transport in many hidromagnetic system, both astrophysical and geophysical. The waves have been observed in interplanetary plasmas, at the solar photosphere and terrestrial magnetosphere, where they can lead to magnetic activities called HILDCAAs. Due to their high level of ocurrence and important role in the connection and exchange of information between different regions of space, the waves constitute an important field of study, through their investigation in the interplanetary space and laboratories and also by computational simulations. © by the Sociedade Brasileira de Física.