How Do Magnetic Field Lines Break?

[SHISHKABOB]

When people talk about sunspots and the solar cycle and stuff like that, they often mention magnetic field lines poking through the surface of the sun. I'm pretty sure I get why the magnetic field lines would be twisted up by the non-uniform rotation of the sun, and why they would poke out of the surface.

What I totally *do not* get, is how the heck a magnetic field line *breaks*. This seems to me that it would mean that magnetic field lines are physical things... or rather that they are "made of something", like some kind of material.

I just don't have any sort of idea of how a magnetic field line could be broken based on my understanding of what a field line is. Is this something that I will learn about in E&M courses?

 

[Bobbywhy]

SHISHKABOB, You may learn about the “breaking” and "reconnecting" of magnetic lines here:

“Magnetic reconnection (henceforth called "reconnection") refers to the breaking and reconnecting of oppositely directed magnetic field lines in a plasma. In the process, magnetic field energy is converted to plasma kinetic and thermal energy.”
http://mrx.pppl.gov/Physics/physics.html

For a real-life experiment see:
“The Magnetic Reconnection Experiment”
http://mrx.pppl.gov/

For a site that uses great graphics to explain the process see:
http://www.aldebaran.cz/astrofyzika/plazma/reconnection_en.html

Finally, see our old friend (and the references at the bottom) Wikipedia:
http://en.wikipedia.org/wiki/Magnetic_reconnection

Cheers,
Bobbywhy

 

[SHISHKABOB]

thanks, can't believe I didn't think of looking on wikipedia >.>

 

[Q-reeus]

Very interesting plasma physics phenomenon. Astounded though at the widespread and officially sanctioned use of terminology that implies a failure of one of the four Maxwell eqn's: ∇.B = 0. That eq'n, which in effect states magnetic monopoles do not exist, guarantees there can be no such thing as an 'open field line'. Yet that terminology is used in describing line configurations in third illustration at http://www.aldebaran.cz/astrofyzika/plazma/reconnection_en.html (3rd link given in #2). Generally, 'reconnection of field lines' implies they can have 'loose ends' which is a violation of ∇.B = 0. So what actually happens is the plasma as current source reconfigures in such a way that magnetic field lines, which always form closed loops, reconfigures to give the appearance of 'breaking' and 'reattaching' of such lines. This is just a vector summation situation and at no space-time region will there be lines that are not continuous. Disappointing that none of those articles linked in #2 make the point that ∇.B = 0 is not being violated.

 

[sardar]

I can explain that magnetic field lines are not physical objects, but rather a representation of the direction and strength of the magnetic field. They are used to visualize the behavior of the magnetic field and how it interacts with other objects.

The breaking of magnetic field lines is a concept that is often used to explain the process of magnetic reconnection. This is a phenomenon where the magnetic field lines from two different regions come into contact and merge, releasing a large amount of energy. This can happen on the sun's surface, causing sunspots, and also in Earth's magnetic field, leading to phenomena such as auroras.

The idea of breaking magnetic field lines is not meant to be taken literally, but rather as a way to describe the change in the magnetic field's behavior. It is a way to visualize the process of magnetic reconnection, which is important in understanding the dynamics of the sun and other astronomical objects.

In your E&M courses, you will learn more about the nature of magnetic fields and how they interact with charged particles. This will help you better understand the concept of magnetic field lines and how they can change and break under certain conditions. Keep in mind that they are a mathematical representation of a physical phenomenon and not physical objects themselves.