Observation of improved behavior by electrode biasing of a toroidal plasma having no poloidal magnetic field

Suppression of electron shading effect by a counter radio frequency bias in plasma etchingPreparation of cubic boron nitride films by radio frequency bias sputtering Evolution of the plasma rotation and the radial electric field for a toroidal plasma in the Pfirsch-Schlüter and plateau regimes subject to a biased electrode An experimental study on behavior of radial profile of the floating potential with different biased electrode ring configurations has been carried out in a currentless magnetized toroidal plasma. Radial profile of the floating potential has been measured by biasing single ring of various sizes and two rings. It is observed that floating potential profile of a well shaped with controllable depth, hill-cum-well shaped, and almost flat positive potential can be obtained. Results on parameter dependence studies of floating potential on the bias voltage, magnetic field, and gas pressure are presented.

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“…On the other hand, floating potential increases with the bias voltage and then saturates, as was reported earlier in Ref. 16.…”

Section: A Results From Single Ring Experimentssupporting

confidence: 79%

Radial profile of plasma potential with various biased electrode ring configurations in a toroidal plasma

Chaube

Jain

1996

Physics of Plasmas

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“…As a result most of the plasma resides on the outboard. This is consistent with the experimentally measured profile of density in BETA [4,10] where profiles are more sharp in the inboard than in the outboard, which indicates an accumulation of the plasma on the outboard.…”

supporting

confidence: 90%

“…We now present some results from a device called BETA [4] which are consistent with this theoretical study. For typical BETA parameters of the argon plasma R 45 cm, a 15 cm, plasma radius r 10 cm, T e ϳ 5 eV, T i ϳ 0.2 eV, B 200 G, plasma density N ϳ 5 3 10 10 cm 23 , neutral density N n ϳ 1.5 3 10 13 cm 23 , k u ϳ 0.3 cm 21 , and equilibrium scale lengths of density, potential, and mean rms fluctuation level areϳ15 cm, we get c s ϳ 3.5 3 10 5 cm͞s, a s ϳ 7 cm, n in ϳ 10 4 s 21 , and ew c ͞T e ഠ 55%.…”

supporting

confidence: 79%

“…The mechanism involving poloidal rotation and improved confinement finds strong support in a recent experiment by Jain [4] where the rotation is enhanced by a biased probe driven radial electric field. The upshot of all this is that the fluctuation driven and/or externally assisted poloidal rotation or radial electric field is one of the primary reasons for enhanced confinement in CTD.…”

mentioning

confidence: 67%

“…Besides, the suppression of fluctuations by flows in CTD has been experimentally demonstrated by Jain [4]. It thus appears that the CTD can serve as a test bed for some of the hot ideas which are being currently discussed in high confinement tokamak physics.…”

mentioning

confidence: 92%

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Equilibrium and Fluctuations in a Plasma Confined in a Pure Toroidal Field

1996

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Radial distribution of the plasma potential in a cylindrical plasma column with a longitudinal magnetic field

et al. 2021

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The possibility of controlling the electrostatic field distribution in plasma has yielded wide prospects for modern technologies. As a magnetic field primarily allows for creating electric fields in plasma, it serves as an additional obstacle for the current flow through a medium. In the present paper, an axially symmetric system is considered in which the magnetic field is directed along the axis and concentric electrodes are located at the ends. The electrodes are negatively biased. A model which solves the problem of the radial distribution of the plasma potential inside the cylindrical plasma column supported by the end electrodes is proposed. The most commonly encountered configurations of the electrical connection for the end electrodes are considered, and the particular solutions to the problem of the radial distribution are presented. The contribution of ions and electrons to the transverse conductivity is evaluated in detail. The influence of a thermionic element on the radial profile of the plasma potential is considered. To verify the proposed model, an experimental study of the reflex discharge is carried out with both cold electrodes and a thermionic element on the axis. A comparison of the computational model results with experimental data is given. The presented model makes it possible to solve the problem concerning the plasma potential distribution in the case of an arbitrary number of end electrodes, and also to take into account the inhomogeneity of the distribution of plasma density, neutral gas pressure and electron temperature along the radius.

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Observation of improved behavior by electrode biasing of a toroidal plasma having no poloidal magnetic field

Cited by 17 publications

References 12 publications

Radial profile of plasma potential with various biased electrode ring configurations in a toroidal plasma

Radial profile of plasma potential with various biased electrode ring configurations in a toroidal plasma

Equilibrium and Fluctuations in a Plasma Confined in a Pure Toroidal Field

Radial distribution of the plasma potential in a cylindrical plasma column with a longitudinal magnetic field

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