Study of RF Stray Currents in ITER Neutral Beam Test Facilities
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...
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MDPI AG
2021-11-01
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| Series: | Applied Sciences |
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| Online Access: | https://www.mdpi.com/2076-3417/11/23/11126 |
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| author | Riccardo Casagrande Alberto Maistrello Marco De Nardi Mattia Dan Mauro Recchia |
| author_facet | Riccardo Casagrande Alberto Maistrello Marco De Nardi Mattia Dan Mauro Recchia |
| author_sort | Riccardo Casagrande |
| collection | DOAJ |
| description | 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. |
| first_indexed | 2024-03-10T04:58:24Z |
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| institution | Directory Open Access Journal |
| issn | 2076-3417 |
| language | English |
| last_indexed | 2024-03-10T04:58:24Z |
| publishDate | 2021-11-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Applied Sciences |
| spelling | doaj.art-a38d1d869d6c498f997e98d34b23ab8a2023-11-23T02:02:56ZengMDPI AGApplied Sciences2076-34172021-11-0111231112610.3390/app112311126Study of RF Stray Currents in ITER Neutral Beam Test FacilitiesRiccardo Casagrande0Alberto Maistrello1Marco De Nardi2Mattia Dan3Mauro Recchia4Consorzio RFX (CNR, ENEA, INFN, Università di Padova, Acciaierie Venete SpA), Corso Stati Uniti 4, 35127 Padova, ItalyConsorzio RFX (CNR, ENEA, INFN, Università di Padova, Acciaierie Venete SpA), Corso Stati Uniti 4, 35127 Padova, ItalyConsorzio RFX (CNR, ENEA, INFN, Università di Padova, Acciaierie Venete SpA), Corso Stati Uniti 4, 35127 Padova, ItalyConsorzio RFX (CNR, ENEA, INFN, Università di Padova, Acciaierie Venete SpA), Corso Stati Uniti 4, 35127 Padova, ItalyConsorzio RFX (CNR, ENEA, INFN, Università di Padova, Acciaierie Venete SpA), Corso Stati Uniti 4, 35127 Padova, ItalyThe 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.https://www.mdpi.com/2076-3417/11/23/11126ITER NBIion sources for fusionNBTFSPIDERRF stray currents |
| spellingShingle | Riccardo Casagrande Alberto Maistrello Marco De Nardi Mattia Dan Mauro Recchia Study of RF Stray Currents in ITER Neutral Beam Test Facilities Applied Sciences ITER NBI ion sources for fusion NBTF SPIDER RF stray currents |
| title | Study of RF Stray Currents in ITER Neutral Beam Test Facilities |
| title_full | Study of RF Stray Currents in ITER Neutral Beam Test Facilities |
| title_fullStr | Study of RF Stray Currents in ITER Neutral Beam Test Facilities |
| title_full_unstemmed | Study of RF Stray Currents in ITER Neutral Beam Test Facilities |
| title_short | Study of RF Stray Currents in ITER Neutral Beam Test Facilities |
| title_sort | study of rf stray currents in iter neutral beam test facilities |
| topic | ITER NBI ion sources for fusion NBTF SPIDER RF stray currents |
| url | https://www.mdpi.com/2076-3417/11/23/11126 |
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