| Parameter Description | Argument Order | Argument Name | Units | Default Value |
|---|---|---|---|---|
| Length | 1 | L | cm | |
| Magnetic Field | 2 | B | kG | |
| Magnetic Field Gradient | 3 | Gb | kG/cm | |
| Electric Field | 4 | E | kV/cm | |
| Electric Field Gradient | 5 | Ge | kV/cm **2 |
R denotes a bend element where bending is provided by a combination of electrostatic and magnetic forces. Bending occurs in the horizontal plane and results from an electric field of magnitude $E_0$ in the $x$ direction and a magnetic field of magnitude $B_0$ in the $-y$ direction. A transverse field gradient may be present in either or both static fields. The first three arguments in the element specification are the same as those used for a conventional (strictly magnetic) combined function magnet (see: B-combined function magnet). Two additional arguments follow: the electric field on the central orbit, E [kV/cm] and its gradient, Ge [kV/cm2]. For cylindrical electrodes, the electric field near the central orbit is given by the following equation $$ \begin{eqnarray} \phi(x,y) & = & R_0 E_0 \ln(1+x/R_0) \\ E_x(x,y) & = & - E_0 (1-x/R_0) + ... ,\\ E_y(x,y) & = & + y/R_0 + ... , \end{eqnarray} $$ where $R_0$ is the bending radius set by the combined effect of the electric and magnetic fields. In this case one has $G_e = -E_0/R_0$. Magnetic edge focusing is modeled with a separate element. (see: G-magnet edge). For spherical electrostatic deflector plates, one has $G_e = - 2 E_0 /R_0$. For toroidal plates, $G_e = - (1+ k) E_0/R_0 $ with $k$ the ratio of the electrode curvature in the bending plane to that in the transverse plane. If the electrodes plates are plane and parallel, $R_0 = \infty$, the magnetic and electric bending forces cancel each other out and one has a classic Wien filter.
Examples: R L[cm]= 139.62634 B[kG]=0 Gb[kG/cm]=0 E[kV/cm]= 0.9999869 Ge[kV/cm**2]=0 ...
ra L[cm]= 8.7266461 B[kG]=0 Gb[kG/cm]=0 E[kV/cm]= 0.9999869 Ge[kV/cm**2]=0