### field lines

(lines showing the pattern of a mathematical field)

**Field lines** are imaginary lines showing the direction of
vectors in a (mathematical) vector field (as well as any
physical field the mathematical field represents), often included in
illustrations of fields. In an illustration, labeling might reveal
which of the two possible directions the vectors are pointed, since
simple lines don't reveal that. Field lines are commonly used to
illustrate magnetic fields (**magnetic field lines**)
and often the term is used to describe phenomena that follow paths
that could form a field line, e.g., "along the field lines, ...".
A simple experiment of a magnet under a piece of paper with (tiny
stick-like) iron filings sitting on top results in the filings
illustrating the field in a "field line" manner.

Field lines can also be used to illustrate other mathematical and
physical fields, including electric fields and gravitational fields.

(*physics,mathematics,gravity,electromagnetism*)
**Further reading:**

http://en.wikipedia.org/wiki/Field_line

**Referenced by pages:**

Alfvén wave

Blandford-Payne mechanism (BP process)

curvature radiation

electric dipole radiation

flux freezing

magnetic anomaly

pulsar (PSR)

sunspot

Sun surface features

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