Expert: Jayendra Upadhye - 4/2/2008

Question
Hello,
The sun elements are Hydrogen and Helium only.
Magnetic activity is associated with Iron,however powerful
magnetic storms are observed in the so called Corona.
Could you please explain in detail this phenomena.
Many thanks


Answer
Hi Shalom,
I hope you are the same one who asked me a question earlier.

Actually Most matter on the sun is "not in its normal" state.
It is in the state called PLASMA.

Plasma shows very strong magnetic properties as it is a collection of loose charged particles at high temperature (kinetic energy as well as internal energy).

The law's of electromagnetic induction are very simple.
Any area of flowing charge will have an associated magnetic field depending on the direction of the flow.

That is why conductors carrying currents have associated magnetic fields, even if the conductors are of copper or alluminum (and not iron).

The magnetic fields associated with iron are
1 - permanent magnetic fields as iron has good retentivity.
2 - transient magnetic fields as in transformer cores. Once switched off, the core does not remain magnetic except for rersidual magnetism. (It is this residual magnetic property of iron cores that leads to hysteris loss (known as iron loss in ac motors and transformers).

The solar plasma is very much the main constituent in the intermediate zone above the core. This is the convective zone where heat is carried off the core by convective heat transfer. Within the core which is opaque to even gamma rays, due to temperature and density, indirect atom to atom radiative transfer only can occur, making light take 100,000 years or more to come inot the convective area from the core, by atom to atom jumps and re-radiation.

Your precise answer is in link 3.

Mind you but all what i said above is put there in a more technical manner. Reading up Magneto-hydro-Dynamics or MHD would be a good idea.
On earth, scientists create a plasma by burning fuel and then subject it to strong magnetic fields to study MHD.

The charge particles in the convective cells set up the solar magnetic field.
refer:-
1 - http://en.wikipedia.org/wiki/Sun
2 - http://solar-heliospheric.engin.umich.edu/hjenning/ConvectiveZone.html
3 - http://en.wikipedia.org/wiki/Solar_dynamo

Hope that suffices.
regards
Jayen