Regarding gas jets for laser interactions, such as generation of high harmonics - I've seen articles that discuss nozzle designs for producing supersonic gas jets. Those articles always discuss a converging-diverging nozzle design for supersonic jets. I wanted to ask if it's possible to produce a supersonic gas jet also with a simple cylindrical nozzle? I'll appreciate if you can also refer me to a specific scientific source discussing this point.
Hello, with a cylindrical nozzle you cannot "create" a supersonic jet. If the medium had been supersonic before, the nozzle won't change much, but if it is subsonic, the nozzle will not change anything as well.
The German wikipedia page about the Laval nozzle will give you a good start into the theory - provided you can get a good translation:
https://de.wikipedia.org/wiki/Lavaldüse
(I'm sorry, but the English page cannot keep up.)
From theory side i believe its pretty clear that it wont work for ideal nozzles. If you just wish to have a short density ramp it might be worth considering that flow on CNC drilled metal boundaries behaves complicated. Also already "small" deviations like a not fully drilled hole at the exit of the cylinder might partially fullfill the converging/diverging condition.
Hi,
Get in touch with François Sylla from SourceLAB (http://www.sourcelab-plasma.com/) in France. Maybe he can help!
Hi,
this was investigated experimentally, you can read i.e. my paper "Hybrid particle-in-cell/molecular dynamics simulation of swift-ion tracks in LiF" , Yaroslav Cherednikov · Si Neng Sun · Herbert M. Urbassek, Physical Review B 06/2013; 87(24):245424-. DOI:10.1103/PhysRevB.87.245424, where we modelled such processes in ionic crystals, where we get the strongest efects in such cylinders. The sputtering is always normal to surface, that is these phenomena have an electrostatic nature rather than aerodynamical.
No this is absolutely impossible. A gas dynamics simulations clearly demonstrate this.
Hi,
In ordinary cylindrical nozzle it is not possible. But you can use the de Laval nozzle where supersonic gas jets are achieved (i.e. in plasma or cold spray process).
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