Merge pull request #605 from bmad-sim/devel/44

Added polarity parameter to em_field.
bmad-sim · Oct 30, 2023 · 86933da · 86933da
2 parents 7d8c13e + 7b5e18c
commit 86933da
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diff --git a/bmad/code/valid_tracking_method.f90 b/bmad/code/valid_tracking_method.f90
@@ -135,6 +135,8 @@ function valid_tracking_method (ele, species, tracking_method) result (is_valid)
   select case (method)
   case (symp_lie_ptc$, taylor$, runge_kutta$, time_runge_kutta$, custom$)
     is_valid = .true.
+  case (symp_lie_bmad$)
+    if (associated(ele%cartesian_map) .and. ele%field_calc == fieldmap$) is_valid = .true.
   end select
 
 case (floor_shift$, fiducial$)

diff --git a/bmad/doc/elements.tex b/bmad/doc/elements.tex
@@ -1811,6 +1811,13 @@ \section{EM_Field}
 Attributes specific to an \vn{em_field} element are:
 \begin{example}
   constant_ref_energy = <Logical> ! Is the reference energy constant? Default = True.
+  polarity   = <Real>  ! For scaling the field.
+\end{example}
+
+The \vn{polarity} value is used to scale the magnetic field. By
+default, \vn{polarity} has a value of 1.0.  Example:
+\begin{example}
+  wig1: wiggler, l = 1.6, polarity = -1, cartesian_map = \{...\}
 \end{example}
 
 If the \vn{constant_ref_energy} logical is set to \vn{True} (the default), the reference energy

diff --git a/bmad/modules/attribute_mod.f90 b/bmad/modules/attribute_mod.f90
@@ -1125,6 +1125,8 @@ subroutine init_attribute_name_array ()
 call init_attribute_name1 (em_field$, phi0$,                        'PHI0')
 call init_attribute_name1 (em_field$, phi0_err$,                    'PHI0_ERR')
 call init_attribute_name1 (em_field$, constant_ref_energy$,         'CONSTANT_REF_ENERGY')
+call init_attribute_name1 (em_field$, polarity$,                    'POLARITY')
+
 
 call init_attribute_name1 (girder$, l$,                             'L', dependent$)
 call init_attribute_name1 (girder$, x_offset$,                      'X_OFFSET')

diff --git a/bmad/parsing/set_ele_defaults.f90 b/bmad/parsing/set_ele_defaults.f90
@@ -144,6 +144,7 @@ subroutine set_ele_defaults (ele, do_allocate)
   ele%value(fringe_type$) = full$
   ele%value(field_autoscale$) = 1
   ele%value(constant_ref_energy$) = true$
+  ele%value(polarity$) = 1.0
 
 case (fiducial$)
   ele%value(origin_ele_ref_pt$) = center_pt$