by astro123 » Mon Apr 17, 2006 2:26 pm
If field lines were purely conceptual aids, one could pick any path parallel to the field and all such paths would be equivalent. But this is not right either!
We see charged particles (and magnetic particles) concentrated along specific lines. These lines appear to be relatively permanent, they move with the plasma, and particles attached to a given field line do not move between lines. This argument over reality is really an abstract philosophical one, as many phenomena can be described as fictitious when viewed in the context of a particular paradigm. However the plasma particles aren't capable of "concepts" so they must be responding to some property of the potential. Whether you view the resulting "field line" or flux tube (which you can clearly see and measure, along with its effects and interactions with the surroundings) as a "real" object or not, is up to you! Real-life magnetic fields encountered in astrophysics are not smooth well behaved things, they are tangled and complex, the everyday laws of physics are only typically valid over scales on which the field is smooth. The theory of magnetohydrodynamics (MHD) takes over in these situations. Unfortunately its not easy to comprehend.
Check out the SOHO website and science.nasa.gov/ssl/pad/solar/the_key.htm
(thanks for pointing out my mistake in oversimplifying)
If field lines were purely conceptual aids, one could pick any path parallel to the field and all such paths would be equivalent. But this is not right either!
We see charged particles (and magnetic particles) concentrated along specific lines. These lines appear to be relatively permanent, they move with the plasma, and particles attached to a given field line do not move between lines. This argument over reality is really an abstract philosophical one, as many phenomena can be described as fictitious when viewed in the context of a particular paradigm. However the plasma particles aren't capable of "concepts" so they must be responding to some property of the potential. Whether you view the resulting "field line" or flux tube (which you can clearly see and measure, along with its effects and interactions with the surroundings) as a "real" object or not, is up to you! Real-life magnetic fields encountered in astrophysics are not smooth well behaved things, they are tangled and complex, the everyday laws of physics are only typically valid over scales on which the field is smooth. The theory of magnetohydrodynamics (MHD) takes over in these situations. Unfortunately its not easy to comprehend. :? Check out the SOHO website and science.nasa.gov/ssl/pad/solar/the_key.htm
(thanks for pointing out my mistake in oversimplifying)