Understanding SDBD Actuators: An Experimental Study on Plasma Characteristics

The working mechanisms of surface dielectric barrier discharge (SDBD) plasma actuators foreseen as aerodynamic control devices is investigated experimentally on a common platform, referred to as the NATO-AVT-RTO-190 test case. A better understanding of the working principle and characteristics of SDBD paves the way for more efficient and safe use of plasma actuators in aerodynamic applications. In this study, a characterisation of the plasma is done by current measurements, fast-camera plasma imaging and force measurements. Furthermore, more advanced plasma characteristics such as reduced electric field and excited species population are found by Optical Emission Spectroscopy. The collective goal of this research is to contribute to a database which can also be used for numerical verification and validation by varying the key parameters such as frequency and voltage

Cross-field plasma blob motion in an open magnetic field line configuration

The radial propagation of blobs generated from plasma instabilities is investigated in an open magnetic field line configuration. Blob cross-field velocities and sizes are obtained from internal probe measurements using pattern recognition. By varying the ion mass, the normalized vertical blob scale a approximate to is scanned from a approximate to 1. An analytical expression for the blob velocity including cross-field ion polarization currents, parallel currents to the sheath, and ion-neutral collisions is derived and shows good quantitative agreement with the experimental data. In agreement with previous theoretical studies, this scaling shows that, for a approximate to 1 it is limited by parallel currents to the sheath

Optically isolated millimeter-wave detector for the Toroidal Plasma Experiment

We have designed and built an optically isolated millimeter-wave detection system to prevent interference from a nearby, powerful, 2.45 GHz microwave source in millimeter-wave propagation experiments in the TORoroidal Plasma EXperiment (TORPEX). A series of tests demonstrates excellent system noise immunity and the ability to observe effects that cannot be resolved in a setup using a bare Schottky diode detector

A new fast ion source and detector for investigating the interaction of turbulence with supra-thermal ions in a simple magnetized toroidal plasma.

A specific experimental apparatus consisting of an ion source and a detector for the investigation of the interaction between supra-thermal ions and drift-wave turbulence is developed on the TORoidal Plasma Experiment (TORPEX). Due to the small plasma temperature (~5eV), a spatially localized, small-size ion source (~4cm) mounted inside the vacuum vessel, with relatively low ion energy (~100eV-1keV) can be used. The source consists of an aluminosilicate Li-6 ion emitter (6 mm diameter, 10-30μA current) installed on a 2D poloidally moving system. The location, energy and current density profile of the ion beam will be measured using a 2D movable gridded energy analyzer

Fast ion source and detector for investigating the interaction of turbulence with suprathermal ions in a low temperature toroidal plasma - art. no. 10F503

A specific experimental apparatus consisting of an ion source and a detector for the investigation of the interaction between suprathermal ions and drift-wave turbulence is developed on the toroidal plasma experiment. Due to the low plasma temperature (similar to 5 eV), a spatially localized, small-size ion source (similar to 4 cm) mounted inside the vacuum vessel with relatively low ion energy (similar to 100 eV-1 keV) can be used. The source consists of an aluminosilicate Li-6 ion emitter (6 mm diameter, 10-30 mu A current) installed on a two-dimensional (2D) poloidally moving system. The location, energy, and current density profile of the ion beam will be measured using a 2D movable gridded energy analyzer. (c) 2006 American Institute of Physics

Statistical properties of electrostatic turbulence in toroidal magnetized plasmas (Invited paper)

A unique parabolic relation is observed to link skewness and kurtosis of density fluctuation signals, measured over the whole cross-section of the simple toroidal device TORPEX for a broad range of experimental conditions. This relationship is also valid for density fluctuation signals measured in the scrape-off layer of the TCV tokamak. All the probability density functions (PDFs) of the measured signals, including those characterized by a negative skewness, are universally described by a special case of the beta distribution. In TORPEX, fluctuations in the drift-interchange frequency range are necessary and sufficient to assure that PDFs can be described by this specific beta distribution. For a more detailed plasma scenario, it is shown that electron temperature and plasma potential fluctuations have different statistical properties compared with the density