Quote from Physics World, May 1996 p7 - a report on the Cluster
mission to study small-scale fluctuations in earth's magnetic
and electric fields.
"The solar wind is a magnetised plasma. When it reaches the
Earth's magnetic field, it is repelled, and therefore most solar
particles are excluded from the Earth's magnetosphere. However,
some particles get through, creating auroras in the sky near the
magnetic poles.....but exactly how these particles penetrate
remains a mystery."
(i) Can a plasma be magnetised??
(ii) I would normally deduct marks if a student wrote that a
charged particle was "repelled" by a magnetic field.
(iii) I would expect the solar wind particles to follow helical
trajectories, tracking the magnetic field lines down to the
Earth's magnetic poles - hence the appearance of the Aurorae
at high latitudes. Surely this should not be made to sound
mysterious?
The report goes on to make it clear that it is the interaction
between the magnetosphere and the fluctuating solar wind that is
the focus of interest, where the phenomena are not fully
understood.
Am I being too harsh in thinking that the outline sketched by
the journalist is rather bad writing (especially in a physics
journal), or are there aspects of the problem that I have
missed?