(between the two capacitors) rises rapidly until the main spark gap discharges, firing the laser. The speed of either circuit is increased in two steps. First, the inductance of all components is reduced by shortening and widening conductors and by squeezing the circuit into a flat rectangle. The total inductance is the sum of the components: The intense discharge is reported to distort oscilloscopes nearby. This can be reduced by building the laser symmetrically into a grounded cylinder with the spark gap at the bottom, the laser at the top, capacitor 1 left and right, and capacitor 2 left and right stacked onto capacitor 1. This has the further advantage of reducing the inductance. And this has the disadvantage that the laser channel cannot be inspected for sparks anymore. Secondly, transmission line theory and waveguide theory is applied to achieve a traveling wave excitation. Measured nitrogen laser pulses are so long that the second step is unimportant. From this analysis it follows that: the end mirror and the spark gap are on the same side a long narrow laser at atmospheric pressures is ineffective Spark gap Paschen's law states that the length of the spark gap is inverse-proportional to the pressure. For a fixed length to diameter ratio of the spark, the inductance is proportional to the length (source , compare with: dipole antenna ). Thus the electrodes of the spark gap are glued or welded on a dielectric spacer-ring. To reduce the danger due to the pressure, the volume is minimized. To prevent sparks outside space ring in the low pressure the spacer usually gets thicker outwards in an s-shaped manner. Connection between spark gap and laser channel based on traveling wave theory: The low inductance spark gap may be inserted into a strip transmission line biconical spark gap biconical spark gap biconical spark gap The breakdown voltage is low for helium, medium for nitrogen and high for SF6, though nothing is said about the spark thickness variations. Rise times as high as 8×1010 A/s are possible with a spark gap. This nicely matches the typical rise times of 1×10−8 s and typical currents of 1×103 A occurring in nitrogen lasers. A cascade of spark gaps allows to use a weak trigger pulse to initiate a streamer in the smaller gap, wait for its transition into an arc, and then for this arc to extend into the larger gap.