The discussion revolves around the generation of a magnetic field in the Earth's outer core, focusing on the implications of charge neutrality in a convecting and conductive fluid. Participants explore theoretical and conceptual aspects of magnetism, particularly in relation to Maxwell's equations and the behavior of charged particles in motion.
Participants express differing views on the mechanisms by which a magnetic field can be generated in a neutral medium, with no consensus reached on the explanations provided.
The discussion includes assumptions about the behavior of charged particles in a magnetic field and the conditions under which charge separation might occur. There are also references to external sources that may not be universally accepted or verified within the thread.
A current-carrying wire is charge-neutral, nevertheless it generates a magnetic field. Its negative charges (mobile electrons) move, but the equal amount of positive charge (metallic ions) does not.AustinLee said:Even if the outer core is convecting and conductive it is still charge neutral, so how can a Magnetic field be generated?
Okay I can understand the neutrality. However does that mean the Earth's outer core has a electrical current?jtbell said:A current-carrying wire is charge-neutral, nevertheless it generates a magnetic field. Its negative charges (mobile electrons) move, but the equal amount of positive charge (metallic ions) does not.
AustinLee said:However does that mean the Earth's outer core has a electrical current?
So let's assume there is a magnetic field (maybe much weaker than the magnetic field of earth) and a neutral conductive liquid is moving in this field. Then there will be some charge separation as the electrons and nuclear charges are deflected in different directions. The amount of charge built up will be limited by the build up of an electric field till some equilibrium is reached. Nevertheless the speed of negative and positive charges may be different thus leading to an additional magnetic field. If oriented parallel to the original field, this can lead to a rapid build up of a strong magentic field starting from a small random field fluctuation.AustinLee said:Even if the outer core is convecting and conductive it is still charge neutral, so how can a Magnetic field be generated? Maxwells Equation say there needs to be net charge moving for a Magnetic field to be generated.