Why does magnetic field lines go from plus to minus?

My question is why the magnetic field lines goes from plus to minus, if there was two charge. Is it true or isn't it true.

-
Hi user1098185, and welcome to Physics Stack Exchange! Could you expand on your question? What reason do you have to believe this is true or not true? Where else have you looked to try to find the answer, and what didn't you understand about what you found? etc. – David Z Jun 10 '12 at 15:45
Hi, and thanks! My teacher told me today that the mangnetic fields goes from the plus to the minus. A picture can show what i mean: tinypic.com/r/ifoqo9/6 – user1098185 Jun 10 '12 at 16:17
What are "plus" and "minus"? – Ignacio Vazquez-Abrams Jun 10 '12 at 16:26
Dipole. The magnetic charges. Dont know what to call it, but if you look at the picture you will see it. The round circle with + and - – user1098185 Jun 10 '12 at 16:48
I think if you look carefully at the picture you mentioned, it's showing the electric field, not magnetic. The $E$ label and arrow are the big hit ($E$ is for electric field). The $+$ and $-$ would then be electric charges. Also, $+$ and $-$ are not normally used for magnetic fields, which are always loops. The $N$ and $S$ designations, indicating loops flowing "out" or "in" from bunched-up bundles of such loops, are used instead. – Terry Bollinger Jun 10 '12 at 16:51

I think if you look carefully at the picture you mentioned, it's showing the electric field, not magnetic. The $E$ label and arrow are the big hit ($E$ is for electric field). The $+$ and $−$ would then be electric charges. Also, $+$ and $−$ are not normally used for magnetic fields, which are always loops. The $N$ and $S$ designations, indicating loops flowing "out" or "in" from bunched-up bundles of such loops, are used instead.