[1] The light generated by an explosion is produced primarily by compression heating of the surrounding air.
Replacement of the air with a noble gas considerably increases the light output; with molecular gases, the energy is consumed partially by dissociation and other processes, while noble gases are monatomic and can only undergo ionization; the ionized gas then produces the light.
For about 0.5 microsecond the shock wave front instabilities are sufficient to create significant striations in the produced light; this effect diminishes as the thickness of the compressed layer increases.
The shock wave reflects after reaching the window at the end of the tube; this yields a brief increase of light intensity.
The intensity of the flash can be increased and its duration decreased by reflecting the shock wave by a suitable obstacle; a foil or a curved glass can be used.
[4] Argon flash is a standard procedure for high-speed photography, especially for photographing explosions,[5] or less commonly for use in high altitude test vehicles.
As the amount of released radiant energy is fairly high, significant heating of the illuminated object can occur.