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1

Liquid micro pulsed plasma thruster

Szelecka A., Kurzyna J., Daniłko D., Barral S.

Nukleonika

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2015

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Vol. 60, No. 2

257--261

EN

A new type of pulsed plasma thruster (PPT) for small satellite propulsion is investigated, of which the most innovative aspect is the use of a non-volatile liquid propellant. The thruster is based on an open capillary design. The thruster achieved a thrust-to-power ratio above 45 μN/W, which constitutes a 5-fold improvement over the water-propelled pulsed plasma thruster, and which is also slightly above the performance of a similarly sized PPT with a solid propellant.

2

Theoretical analysis of the influence of the power supply on breathing oscillations in Hall thrusters

Barral S.

Journal of Technical Physics

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2008

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Vol. 49, no 3-4

177-185

EN

The breathing mode is the best known low-frequency longitudinal bulk instability of Hall thrusters, capable of generating very wide, regular discharge current oscillations in the 10-30 kHz range. This study extends a recent theory of breathing mode oscillations to the case of a non-ideal voltage source. A simple equivalent circuit modeling the AC behavior of the thruster is derived, using R, L and C components. The equivalent circuit explains in a straightforward way why an impedance in series with the generator is usually able to damp oscillations. More generally, the derived equivalent circuit can be expected to greatly improve the understanding of interactions between the thruster and the power processing unit, and in turn to help the design of robust filters.

3

Causality violation in analysis of Hall thruster plasma instabilities

Peradzyński Z., Barral S., Makowski K., Dudeck M.

Journal of Technical Physics

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2008

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Vol. 49, no 3-4

315-327

EN

Using the fluid equations of Hall thruster plasma we analyze the influence of the electron energy balance on the stability of ion sound modes. For sufficiently low frequencies (ω < 5 • 106^6 s-1 in the case of SPT-100) the gains and losses in the source term are approximately equal, thus the temperature can be in principle determined in terms of other dependent variables. This permits one to reduce the number of equations by one. It appears however, that the new system can have in some regions complex characteristics. This in turn implies instability of certain modes with frequencies lower than the critical frequency.

4

Experiments and modelling of electrospinning process

Kowalewski T., Błoński S., Barral S.

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2005

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Vol. 53, nr 4

385-394

EN

Very thin liquid jets can be obtained using electric field, whereas an electrically-driven bending instability occurs that enormously increases the jet path and effectively leads to its thinning by very large ratios, enabling the production of nanometre size fibres. This mechanism, although it was discovered almost one century ago, is not yet fully understood. In the following study, experimental data are collected, with the dual goal of characterizing the electro-spinning of different liquids and evaluating the pertinence of a theoretical model.