Transport phenomena in high-pressure plasmas of complex chemical composition; numerical simulations and experimental validation (ETF.6093)

Research
The most striking feature of complex chemical plasmas is that a minority of species is responsible for the majority of plasma properties. This implies that these plasmas are strongly non-linear and extremely sensitive to external conditions. An example of this non-linear behavior is the sensitivity of metal halide (MH) lamps [1] to the gravitation force: turning from a horizontal to a vertical burning position can change the color of a MH lamp substantially. This is remarkable if we realize that plasmas are ruled by the presence of electrical charged particles (electrons and ions) and that the electrical force on an ion is more than a billion times (10⁹) larger than the gravitation force on that ion.
It is the aim of this project to come to a proper understanding of this type of plasmas by constructing and validating numerical models. For the model construction we will use our own object oriented C++ package PLASIMO, which for this purpose has to be extended. For the experimental validation we plan to use the Poly-Diagnostic Calibration method, which calibrates simple methods such as emission spectrometry against more complicated laser techniques. Most attention will be devoted to the plasmas in MH lamps [1], but insight obtained in this way will certainly benefit the understanding of many other technological plasmas as well. Selecting the MH lamps as carrier of this investigation has the advantage that the models can easily be validated. The expertise at Philips Lighting CDL can be used to compose a rich ensemble of various special model lamps.
Moreover, these lamps can also be used for measurements in remote zero-gravity experiments in space (ISS) and during parabolic flights. These experiments will be performed in a related project in order to understand the impact of gravitation and other segregation driving forces.

Utilization
There are many different ways to create and operate plasmas. Apart from changing the size, power, current waveform or the operational pressure, a large variety of new plasma types can be created by changing the (initial) chemical composition. The huge parameter space of operational conditions has the consequence that the number of high-tech plasma applications in lighting, material sciences and environmental technology is increasing rapidly. But since theory formation is lagging behind, the work on and with new plasma applications mostly follows the laborious empirical way of trial and error. This inefficient procedure can be avoided if a model-developing platform is available on which plasma models can be constructed. Our PLASIMO package, which is already used in several places and for various types of plasmas, is a good candidate for such a platform. If we are able to model in three dimensions the close interplay between transport and chemistry as found in complex chemical plasmas of high-pressure we can certainly get insight in many other technological plasma as well.
Eindhoven University of Technology is surrounded by several small and large companies, working with various high-tech plasma applications. By having a versatile model development platform we certainly strengthen our position as a center of excellence in the field of plasma technology.

More information can be found on the website of the research group:
http://plasimo.phys.tue.nl/
More information in Dutch can be found on:
http://www.einlightred.tue.nl/

Five companies are involved in this project.

Dr. J.A.M. van der Mullen
Technische Universiteit Eindhoven
Technische Natuurkunde
Groep Atoom- en Plasmafysica
Postbus 513
5600 MB Eindhoven
Tel: 040-2474043
Secr: 040-2472550

Dr.ir. W.W. Stoffels
Technische Universiteit Eindhoven
P.O.Box 513
5600 MB Eindhoven

Prof. dr. ir. G.W.M. Kroesen
Technische Universiteit Eindhoven
P.O.Box 513
5600 MB Eindhoven