BMAPXY

Parameter Name	Units	Type	Default	Description
L		double	0.0	length
STRENGTH		double	0.0	factor by which to multiply field
ACCURACY		double	0.0	integration accuracy
METHOD		STRING	NULL	integration method (runge-kutta, bulirsch-stoer, modified-midpoint, two-pass modified-midpoint, leap-frog, non-adaptive runge-kutta
FILENAME		STRING	NULL	name of file containing columns (x, y, Fx, Fy) giving normalized field (Fx, Fy) vs (x, y)

This element simulates transport through a transverse magnetic field specified as a field map. It does this by simply integrating the Lorentz force equation in cartesian coordinates. It does not incorporate changes in the design trajectory resulting from the fields. I.e., if you input a dipole field, it is interpreted as a steering element.

The field map file is an SDDS file with the following columns:

• x, y -- Transverse coordinates in meters (units should be ``m'').
• Fx, Fy -- Normalized field values (no units). The field is multiplied by the value of the STRENGTH parameter to convert it to a local bending radius. For example, if Fx=y and Fy=x, then STRENGTH is the K1 quadrupole parameter.
• Bx, By -- Field values in Tesla (units should be ``T''). The field is still multiplied by the value of the STRENGTH parameter, which is dimensionless. Note: the default value of STRENGTH is 0, so if you don't set it to something, you'll get no effect!

The field map file must contain a rectangular grid of points, equispaced (separately) in x and y. There should be no missing values in the grid (this is not checked by elegant). In addition, the x values must vary fastest as the values are accessed in row order. To ensure that this is the case, use the following command on the field file: