Progress with the colliding shock lens.
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Date
2013
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Abstract
The Colliding Shock Lens (CSL) exploits the interference of shock waves in a gas to
form a region in which high pressure, temperature and density change the refractive
index of the gas, making it possible to focus laser light. They are real optical
elements, sometimes have very good optical qualities and can be made out of air.
CSL's are dynamic lenses, which last for a few microseconds and are always evolving.
As gas structures, they can be applied to focus high power laser light when solid
lenses would be damaged. The shocks are generated by spark gaps or exploding
wires.
In the former case, ignitrons were used to trigger the CSL circuit but are unreliable
and have become obsolete. In this thesis an alternative, more reliable and cheaper
trigger mechanism is investigated, using needle pins.
The CSL's that were tested previously were too small for any practical use and
in this thesis a continuation into the feasibility of scaling the optical aperture of the
CSL is investigated.
Another application of colliding shocks is the formation of virtual capillaries,
which are a series of spark gaps set out on the surface of a cylinder, forming a cylin-
drical lens. In this thesis a set of exploding wires on a circumference are investigated.
The limitations with the above experiments is that physical probes positioned at
points of interest would interfere with the experiment, hence making it impractical
to determine the parameters of interest as mentioned above. Computational Fluid
Dynamics (CFD) is employed in this thesis to try and alleviate the above problem.
Description
M. Sc. University of KwaZulu-Natal, Durban 2013.
Keywords
Solid state physics., Shock waves., Computational fluid dynamics., High power lasers., Gas lenses., Theses--Physics.