Characteristic performance of radio-frequency (RF) plasma heating using inverter RF power supplies

The operation of SPIDER (Source for the Production of Ions of Deuterium Extracted from Radio-frequency plasma), full-scale prototype of ITER NBI (Neutral Beam Injector) radio-frequency ion source, pointed out deleterious effects caused by stray Radio-Frequency (RF) currents flowing in the electrical equipment not included in the RF power system. MITICA (Megavolt ITER Injector and Concept Advancement), the full-scale prototype of ITER NBI, is characterized by a similar design in terms of layout of the power supplies and connections to the beam source; thus, it is expected to be subject to the RF stray currents problem. SPIDER RF system is composed of four RF generators, four coaxial lines and four RF loads. Each RF generator is rated for operation at 200 kW in the frequency range 0.9 ÷ 1.1 MHz. The power is delivered to the four loads via as many RF coaxial lines, housed inside a multiconductor transmission line. Each load consists of a capacitive matching network and two plasma drivers in series. Due to the presence of stray connections at the generator and beam-source side (e.g., parasitic capacitances), unwanted RF currents can flow through alternative paths and negatively affect the components not intended for transmission of RF power, the output stages of power supplies and several diagnostics installed in the High-Voltage Deck (HVD) and at the beam source. This paper presents the development of a circuital model used to estimate the RF stray currents in SPIDER electrical system; the understanding of this phenomenon and the development of a model with predictive capabilities is fundamental for the assessment of the performance of both SPIDER and MITICA and, in general, of alternative RF system layouts with respect to the stray currents issue.

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STATUS AND PROSPECTS IN STELLARATOR RESEARCH AT IPP KIPT

10.46813/2021-131-003 ◽

2021 ◽

pp. 3-8

Author(s):

V.E. Moiseenko ◽

Yu.V. Kovtun ◽

I.E. Garkusha

Keyword(s):

Radio Frequency ◽

Plasma Heating ◽

Rf Plasma ◽

Theoretical Studies ◽

Tritium Breeding ◽

Start Up

A review of works performed at the Stellarator Department of KIPT is presented. It includes radio frequency (RF) plasma start-up, RF wall conditioning, RF plasma heating and diagnostics improvements at Uragan stellarators, studies of discharges for wall conditioning at Wendelstein 7-X Helias and some theoretical studies on magnetic configurations and tritium breeding. The prospects for the studies are associated with deeper involvement in EUROfusion activities

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Magnetic nozzle radiofrequency plasma thruster approaching twenty percent thruster efficiency

Scientific Reports ◽

10.1038/s41598-021-82471-2 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Kazunori Takahashi

Keyword(s):

Magnetic Field ◽

Electric Propulsion ◽

Transfer Efficiency ◽

Rf Plasma ◽

Power Transfer ◽

Rf Power ◽

Plasma Production ◽

Magnetic Nozzle ◽

Plasma Thruster ◽

Power Transfer Efficiency

AbstractDevelopment of a magnetic nozzle radiofrequency (rf) plasma thruster has been one of challenging topics in space electric propulsion technologies. The thruster typically consists of an rf plasma source and a magnetic nozzle, where the plasma produced inside the source is transported along the magnetic field and expands in the magnetic nozzle. An imparted thrust is significantly affected by the rf power coupling for the plasma production, the plasma transport, the plasma loss to the wall, and the plasma acceleration process in the magnetic nozzle. The rf power transfer efficiency and the imparted thrust are assessed for two types of rf antennas exciting azimuthal mode number of $$m=+1$$ m = + 1 and $$m=0$$ m = 0 , where propellant argon gas is introduced from the upstream of the thruster source tube. The rf power transfer efficiency and the density measured at the radial center for the $$m=+1$$ m = + 1 mode antenna are higher than those for the $$m=0$$ m = 0 mode antenna, while a larger thrust is obtained for the $$m=0$$ m = 0 mode antenna. Two-dimensional plume characterization suggests that the lowered performance for the $$m=+1$$ m = + 1 mode case is due to the plasma production at the radial center, where contribution on a thrust exerted to the magnetic nozzle is weak due to the absence of the radial magnetic field. Subsequently, the configuration is modified so as to introduce the propellant gas near the thruster exit for the $$m=0$$ m = 0 mode configuration and the thruster efficiency approaching twenty percent is successfully obtained, being highest to date in the kW-class magnetic nozzle rf plasma thrusters.

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Uses of radio emission spectroscopy for non-contact and in situ diagnostics of low pressure radio frequency plasma processing

10.21203/rs.3.rs-678053/v1 ◽

2021 ◽

Author(s):

Rajani K. Vijayaraghavan ◽

Sean Kelly ◽

David Coates ◽

Cezar Gaman ◽

Niall MacGearailt ◽

...

Keyword(s):

Radio Emission ◽

Radio Frequency ◽

Emission Spectroscopy ◽

Near Field ◽

Plasma Processing ◽

Diagnostic Technique ◽

Primary Source ◽

Low Pressure ◽

Chamber Pressure ◽

Rf Plasma

Abstract We demonstrate that a passive non-contact diagnostic technique, radio emission spectroscopy (RES), provides a sensitive monitor of currents in a low pressure radio frequency (RF) plasma. A near field magnetic loop antenna was used to capture RF emissions from the plasma without perturbing it. The analysis was implemented for a capacitively coupled RF plasma with an RF supply at a frequency of 13.56 MHz. Real-time measurements are captured in scenarios relevant to contemporary challenges faced during semiconductor fabrication (e.g. window coating and wall disturbance). Exploration of the technique for key equipment parameters including applied RF power, chamber pressure, RF bias frequencies and chamber wall cleanliness shows sensitive and repeatable function. In particular, the induced RES signal was found to vary sensitively to pressure changes and we were able to detect pressure and power variations as low as ~2.5 %/mtorr and ~3.5 %/watt, respectively, during the plasma processing during a trial generic plasma process. Finally, we explored the ability of RES to monitor the operation of a multiple frequency low-pressure RF plasma system (f1 = 2 MHz, f2 = 162 MHz) and intermixing products which suggests strongly that the plasma sheaths are the primary source of this non-linear diode mixing effect.

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Concept Study of Radio Frequency (RF) Plasma Thruster for Space Propulsion

INCAS BULLETIN ◽

10.13111/2066-8201.2016.8.4.2 ◽

2016 ◽

Vol 8 (4) ◽

pp. 15-27

Author(s):

ANDREESCU Anna-Maria Theodora ◽

◽

TEODORESCU Maximilian-Vlad ◽

POPESCU Jeni Alina ◽

VILAG Valeriu-Alexandru ◽

...

Keyword(s):

Radio Frequency ◽

Rf Plasma ◽

Space Propulsion ◽

Concept Study ◽

Plasma Thruster

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The Effect of Plasma Pretreatment on the Morphology and Properties of Hitus Coatings

Powder Metallurgy Progress ◽

10.2478/pmp-2020-0003 ◽

2020 ◽

Vol 20 (1) ◽

pp. 21-29

Author(s):

Lenka Kvetková ◽

Petra Hviščová ◽

Dávid Medveď ◽

František Lofaj

Keyword(s):

Mechanical Properties ◽

New Technology ◽

Rf Plasma ◽

Plasma Power ◽

Rf Power ◽

Properties Of Coatings ◽

Plasma Pretreatment ◽

Significant Change ◽

Scratch Behavior

Abstract WC coatings prepared by High Target Utilization Sputtering (HITUS), a relatively new technology, were deposited on three types of substrates. These were silicon (111), steel (100Cr6), and ceramic (WC-Co). The influence of RF plasma power pretreatment on final properties of WC coatings was investigated with two interlayer materials for bonding. The morphology, roughness, and mechanical properties of coatings were studied. The relation between plasma RF power and roughness was found. No significant change in mechanical properties was detected with change in plasma RF power. The dependence of nanohardness and scratch behavior on HITUS WC coatings was investigated.

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CONTRIBUTION OF THE ELECTRON TUBE DIVISION OF THOMSON-CSF TO RF PLASMA HEATING

Heating in Toroidal Plasmas 1982 ◽

10.1016/b978-1-4832-8428-6.50087-4 ◽

1982 ◽

pp. 761-767

Author(s):

G. Faillon ◽

Ph. Guidée ◽

C. Kalfon

Keyword(s):

Plasma Heating ◽

Rf Plasma ◽

Electron Tube

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Reduce component count and improve efficiency in SLIC and RF power supplies

Analog Circuit Design ◽

10.1016/b978-0-12-800001-4.00148-4 ◽

2015 ◽

pp. 309-310

Author(s):

Tick Houk

Keyword(s):

Power Supplies ◽

Rf Power ◽

Improve Efficiency

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Growth of Catalyst-Free Hexagonal Pyramid-Like InN Nanocolumns on Nitrided Si(111) Substrates via Radio-Frequency Metal–Organic Molecular Beam Epitaxy

Crystals ◽

10.3390/cryst9060291 ◽

2019 ◽

Vol 9 (6) ◽

pp. 291 ◽

Cited By ~ 1

Author(s):

Wei-Chun Chen ◽

Tung-Yuan Yu ◽

Fang-I Lai ◽

Hung-Pin Chen ◽

Yu-Wei Lin ◽

...

Keyword(s):

Electron Microscopy ◽

Molecular Beam Epitaxy ◽

Radio Frequency ◽

Molecular Beam ◽

Chemical Properties ◽

Rf Plasma ◽

Transmission Electron Microscopy Analysis ◽

Organic Precursor ◽

Metal Organic ◽

Hexagonal Pyramid

Hexagonal pyramid-like InN nanocolumns were grown on Si(111) substrates via radio-frequency (RF) metal–organic molecular beam epitaxy (MOMBE) together with a substrate nitridation process. The metal–organic precursor served as a group-III source for the growth of InN nanocolumns. The nitridation of Si(111) under flowing N2 RF plasma and the MOMBE growth of InN nanocolumns on the nitrided Si(111) substrates were investigated along with the effects of growth temperature on the structural, optical, and chemical properties of the InN nanocolumns. Based on X-ray diffraction analysis, highly <0001>-oriented, hexagonal InN nanocolumns were grown on the nitride Si(111) substrates. To evaluate the alignment of arrays, the deviation angles of the InN nanocolumns were measured using scanning electron microscopy. Transmission electron microscopy analysis indicated that the InN nanocolumns were single-phase wurtzite crystals having preferred orientations along the c-axis. Raman spectroscopy confirmed the hexagonal structures of the deposited InN nanocolumns.

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