Figure 6

For each time instant, the picture on the left is the top view of particle distribution, and the adjacent one is the Ex field component on the xy plane. Particle energy is indicated by the normalized colour scale on the top of the left columns. Electrons are shown with deep blue colour. A normalized scale is used for the Ex intensity and indicated on the top of the right columns. The set of parabolic mirror and annular holder has a maximum transversal extension of 900 mm and is 1800 mm far from the emission point.