# FieldLine

class pfsspy.fieldline.FieldLine(x, y, z, output)

Bases: object

A single magnetic field line.

Parameters
• x – Field line coordinates in cartesian coordinates.

• y – Field line coordinates in cartesian coordinates.

• z – Field line coordinates in cartesian coordinates.

• output (Output) – The PFSS output through which this field line was traced.

Attributes Summary

 b_along_fline The magnetic field vectors along the field line. coords Field line SkyCoord. expansion_factor Magnetic field expansion factor. is_open Returns True if one of the field line is connected to the solar surface and one to the outer boundary, False otherwise. polarity Magnetic field line polarity. solar_footpoint Solar surface magnetic field footpoint. source_surface_footpoint Solar surface magnetic field footpoint.

Attributes Documentation

b_along_fline

The magnetic field vectors along the field line.

coords

Field line SkyCoord.

expansion_factor

Magnetic field expansion factor.

The expansion factor is defnied as $$(r_{\odot}^{2} B_{\odot}) / (r_{ss}^{2} B_{ss}))$$

Returns

exp_fact – Field line expansion factor.

Return type

float

is_open

Returns True if one of the field line is connected to the solar surface and one to the outer boundary, False otherwise.

polarity

Magnetic field line polarity.

Returns

pol – 0 if the field line is closed, otherwise sign(Br) of the magnetic field on the solar surface.

Return type

int

solar_footpoint

Solar surface magnetic field footpoint.

This is the ends of the magnetic field line that lies on the solar surface.

Returns

footpoint

Return type

SkyCoord

Notes

For a closed field line, both ends lie on the solar surface. This method returns the field line pointing out from the solar surface in this case.

source_surface_footpoint

Solar surface magnetic field footpoint.

This is the ends of the magnetic field line that lies on the solar surface.

Returns

footpoint

Return type

SkyCoord

Notes

For a closed field line, both ends lie on the solar surface. This method returns the field line pointing out from the solar surface in this case.