Schlieren Imaging Reveals Secrets of Air Spark Gap

Specialised Imaging has produced an application note that describes how its SIM8 ultra high speed camera has been used to capture images of a shock wave produced from a triggered high voltage air spark gap.

A spark gap consists of an arrangement of two conducting electrodes separated by a gap usually filled with a gas such as air, designed to allow an electric spark to pass between the conductors. Understanding this ultra fast process has traditionally presented researchers with many challenges.

Using a SIM8 Camera running at 5 Million frames per second with 35 nanosecond exposures a series of pseudo Schlieren images were captured showing the shock wave resulting from the triggering of a 1.5KV air spark gap. Two of the camera's output triggers were used to synchronize the triggering of a 1.5KV air spark gap and to pre-trigger the xenon flash lamp used as the Schlieren light source.

Schlieren imaging reveals shock waves due to air density gradient and the accompanying change in refractive index. Such shock waves can be deduced from distortions of the background pattern resulting from the change in refractive index due to density gradients.

Specialised Imaging SIM Series ultra fast framing cameras offer the ultimate in ultra-high-speed imaging performance to scientists and engineers across all disciplines. The high performance optical design offers up to 16 images without compromising shading, or parallax. High resolution intensified CCD sensors controlled by state-of-the-art electronics provide almost infinite control over gain and exposure to allow researchers the flexibility to capture even the most difficult phenomena.

To read the application note in full please Click here to download Application Note PDF

For further information about SIM ultra high speed framing cameras please contact Specialised Imaging on

+44-1442-827728 (UK)

+1-951-296-6406 (USA)

+49-8141-666-8950 (Germany)

+86-1068-651-769 (China)

SIM Series ultra fast framing camera

Schlieren imaging of shock wave from triggered air spark gap