European Space Agency

Royal Belgian Institute for Aeronomy

uf425 - evaluate the curvature of the field lines

subroutine  uf425(mgp1, mvb1, mgp2, mvb2, ds, mxnr1, mxnr2)

Parameters:

• mgp1 [zgeo,in] :: Geographic location of the starting point of the field line segment

• mvb1 [zvec,in] :: Magnetic field vector at the starting point

• mgp2 [zgeo,in] :: Geographic location of the last point of the field line segment

• mvb2 [zvec,in] :: Magnetic field vector at the last point

• ds [real8,in] :: Arc length of the segment

• mxnr1 [zvec,out] :: Curvature vector related to the starting point

• mxnr2 [zvec,out] :: Curvature vector related to the last point

Description

The subroutine uf425() evaluates the curvature vectors of a magnetic field line on a segment defined by the arguments mgp1, mvb1, mgp2, mvb2, ds.

Each curvature vector is parallel to the normal vector of the magnetic field line and is inversely proportional to the radius of curvature.

As result, the subroutine provides the curvature vectors at the starting and ending points of the segment.

Diagnostics

None

Common Blocks

• uc160 - general constants

Dependencies

Called by

• uf423 - Runge Kutta step

• uf424 - search the lowest B value

• ut998 - evaluate the magnetic field vector and the normal to the field line

Calls

• um530 - evaluate the magnetic field vector

See also

None

Reported Bugs

None

Examples

None

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UNILIB/tags/v3.02