A Novel Small Period Electromagnetic Undulator for Free Electron Lasers

Numerical calculation shows that optimizing the shape of the current and ferromagnetic area could enhance the field strength of the small-period electromagnetic undulator. Calculations with the nonlinear finite-element method show that this approach could also reduce the space harmonics of the small-period electromagnetic undulator. Based on the numerical data, a model undulator was constructed, and measurements (using a Hall probe) were carried out on it. Experimental results are shown to agree well with numerical calculation. >