Mag dipole sources, defined using prim-sec with a zero-frequency primary actually have a non-zer S_e component if there is variable mu. This has been corrected in the vector potential definition of the sources, and an issue created for the remaining sources. Testing has also been made more robust by using a rawVec source with both S_m and S_e defined which showed a couple bugs in some of the getRHSDeriv_m (which have been corrected), along with a couple minor sizing things in fields derivs

simpegEM/FDEM/FieldsFDEM.py

@@ -147,7 +147,7 @@ class FieldsFDEM_b(FieldsFDEM):
         for i,src in enumerate(srcList): 
             _,S_e = src.eval(self.survey.prob)
             if S_e is not None:
-                e += -self._MeSigmaI*S_e
+                e[:,i] += -self._MeSigmaI*S_e
         return e
 
     def _eSecondaryDeriv_u(self, src, v, adjoint=False):
@@ -162,7 +162,7 @@ class FieldsFDEM_b(FieldsFDEM):
 
         w = self._edgeCurl.T * (self._MfMui * bSolution)
         if S_e is not None:
-            w += -S_e
+            w += -Utils.mkvc(S_e,2)
 
         if not adjoint:
             de_dm = self._MeSigmaIDeriv(w) * v