Note: Electromagnetic field
As summarized in previous chapters, electromagnetic field is mathematical abstraction of two projections and , which meets Maxwell equations
and may be represented by field lines defined as
Definition: Open field line
Field line is open, when it is not closed in plasma.
Definition: Closed field line
Field line is closed, when it is closed in plasma.
Theorem: Magnetic field line equation
Lets assume electromagnetic field with field lines. Then
The theorem results from field line definition directly
which is a vector equation of three scalar equations
and thus may be written