General Physics Seminar Thursday 7 February 2002

Salient features of low temperature dusty plasma and cascaded arc produced plasma

Raj P. Dahiya

Indian Institute of Technology Delhi, India


The presentation, highlighting some salient features of low temperature non-equilibrium strongly coupled plasma and recombining thermal plasma, is divided in three parts. In the first part an overview of Indian Institute of Technology (IIT), Delhi will be presented with a brief description of plasma experiments at the institute, thereafter particle dynamics in dusty plasma experiments performed at TU/e will be highlighted and finally the initial measurements made in Magnum p.s.i. at FOM Institute for Plasma Physics Rijnhuizen will be discussed.

There are 7 Institutes of Technology in India, which are instituted, at different times, by Acts of Parliament. Low temperature plasma experiments are performed at IIT Delhi with orientation towards plasma surface interaction. Cascaded arc produced expanding plasma is used to nitride metallic objects.

In the University of Technology Eindhoven rf plasma reactor, micron size dust particles are injected to study their dynamical behaviour in electropositive and electronegative plasma. Non-symmetrical elongated particles levitated in the sheath region are observed to execute spinning and orbiting motion. A centrally symmetric 2-d void evolves in the cloud of uniform particles and the void closes when electronegative species are added to the plasma. Video images of the non-uniform orbiting particles and uniform particles organising themselves in crystalline state or forming a void structure will be shown. Also the particle cloud undergoing breathing like oscillations will be highlighted through some video clips.

In the final part of the presentation, images of the thermal plasma generated in Magnum p.s.i. experimental system of FOM Institute for Plasma Physics Rijnhuizen will be shown in the absence and presence of axial magnetic field. Potential and electric field profiles along the plasma source arc channel have been measured. Initial measurements have been made for the charged particle flux reaching a target in the expansion chamber. Experiments have been planned to enhance the flux by drawing a current between the target and an auxiliary ring shaped electrode.


Dr. Raj P Dahiya is Professor at Indian Institute of Technology Delhi, India and is presently on a short visit to the FOM Institute for Plasma Physics Rijnhuizen, the Netherlands, where he is involved in performing experiments on Magnum p.s.i.