Key Concepts
============

The simplest way to generate represenations of the SASE field is using the SASE
wavefront function. 

The properties of this wavefield are based on a model of XFEL radiation containing 3 components:

#. A complex time spectrum
#. A complex wavefront
#. A complex pointing angle tilt

 
These are combined in the sase pules module, enabling a replica SASE pulse to be generated:

.. code-block:: python

    import numpy as np
    from phenom.source import sase_pulse
    
    electric_field  = sase_pulse(x = np.linspace(-500e-06, 500e-06, 512), 
                                  y = np.linspace(-500e-063, 500e-06, 512),
                                  t = np.linspace(-100e-15, 100e-15, 512),
                                  photon_energy = 9200.,
                                  pulse_energy = 1e-03,
                                  pulse_duration = 25e-15,
                                  bandwidth = 1e03,
                                  sigma = 100e-06,
                                  div = 1e-03,
                                  x0 = 0.,
                                  y0 = 0.,
                                  t0 = 2e-15,
                                  theta_x = 0,
                                  theta_y = 0.