Machine safety issues with respect to the extension of ECRH systems at ASDEX Upgrade
The beam intensity of electron cyclotron resonance heating at ASDEX Upgrade has the potential to seriously damage in-vessel components, whenever not fully absorbed by the plasma. Operation is, therefore, interlocked with both plasma current and density above a given threshold. Microwave protection d...
| Main Authors: | , , , , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
EDP Sciences
2015-01-01
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| Series: | EPJ Web of Conferences |
| Online Access: | http://dx.doi.org/10.1051/epjconf/20158702010 |
| _version_ | 1818382257168056320 |
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| author | Schuberta Martin Herrmann Albrecht Monaco Francesco Rohde Volker Schütz Harald Stober Jörg Vierle Thomas Vorbrugg Stefan Wagner Dietmar Zasche Dieter Zehetbauer Thomas Zeidner Wolfgang |
| author_facet | Schuberta Martin Herrmann Albrecht Monaco Francesco Rohde Volker Schütz Harald Stober Jörg Vierle Thomas Vorbrugg Stefan Wagner Dietmar Zasche Dieter Zehetbauer Thomas Zeidner Wolfgang |
| author_sort | Schuberta Martin |
| collection | DOAJ |
| description | The beam intensity of electron cyclotron resonance heating at ASDEX Upgrade has the potential to seriously damage in-vessel components, whenever not fully absorbed by the plasma. Operation is, therefore, interlocked with both plasma current and density above a given threshold. Microwave protection detectors installed in several ports on the low field side switch the heating system off, in case the stray radiation exceeds a given threshold. During regular inspections, however, damages were reported in the vicinity of the launchers and in particular around the tiles of the heat shield. On one hand, it was found that insulating material, which may not face the plasma, degraded due to millimetre wave absorption. The waves entered the free space behind the heat shield through gaps. On the other hand, local damage even of metallic components was observed on surfaces, which were directly exposed to the microwave beam. Polarisation errors, which led to a local shine through of significant beam power, were responsible. We note that this happened mainly on the high field side in a certain distance to the microwave protection detectors, which were not triggered by the events. In order to increase the level of protection, we identify three necessary measures: Firstly, polarisation control is to be automated such, that mode content and shine through can be monitored. Secondly, by installing additional detectors, the spatial coverage of stray radiation monitoring is enlarged. Thirdly, the heat shield tiles will be redesigned in order to increase the shielding against millimetre waves. |
| first_indexed | 2024-12-14T02:47:36Z |
| format | Article |
| id | doaj.art-41f48a9d0a554f2c9ff1d74a18fc8301 |
| institution | Directory Open Access Journal |
| issn | 2100-014X |
| language | English |
| last_indexed | 2024-12-14T02:47:36Z |
| publishDate | 2015-01-01 |
| publisher | EDP Sciences |
| record_format | Article |
| series | EPJ Web of Conferences |
| spelling | doaj.art-41f48a9d0a554f2c9ff1d74a18fc83012022-12-21T23:19:50ZengEDP SciencesEPJ Web of Conferences2100-014X2015-01-01870201010.1051/epjconf/20158702010epjconf_ec2015_02010Machine safety issues with respect to the extension of ECRH systems at ASDEX UpgradeSchuberta MartinHerrmann AlbrechtMonaco FrancescoRohde VolkerSchütz HaraldStober JörgVierle ThomasVorbrugg StefanWagner DietmarZasche DieterZehetbauer ThomasZeidner WolfgangThe beam intensity of electron cyclotron resonance heating at ASDEX Upgrade has the potential to seriously damage in-vessel components, whenever not fully absorbed by the plasma. Operation is, therefore, interlocked with both plasma current and density above a given threshold. Microwave protection detectors installed in several ports on the low field side switch the heating system off, in case the stray radiation exceeds a given threshold. During regular inspections, however, damages were reported in the vicinity of the launchers and in particular around the tiles of the heat shield. On one hand, it was found that insulating material, which may not face the plasma, degraded due to millimetre wave absorption. The waves entered the free space behind the heat shield through gaps. On the other hand, local damage even of metallic components was observed on surfaces, which were directly exposed to the microwave beam. Polarisation errors, which led to a local shine through of significant beam power, were responsible. We note that this happened mainly on the high field side in a certain distance to the microwave protection detectors, which were not triggered by the events. In order to increase the level of protection, we identify three necessary measures: Firstly, polarisation control is to be automated such, that mode content and shine through can be monitored. Secondly, by installing additional detectors, the spatial coverage of stray radiation monitoring is enlarged. Thirdly, the heat shield tiles will be redesigned in order to increase the shielding against millimetre waves.http://dx.doi.org/10.1051/epjconf/20158702010 |
| spellingShingle | Schuberta Martin Herrmann Albrecht Monaco Francesco Rohde Volker Schütz Harald Stober Jörg Vierle Thomas Vorbrugg Stefan Wagner Dietmar Zasche Dieter Zehetbauer Thomas Zeidner Wolfgang Machine safety issues with respect to the extension of ECRH systems at ASDEX Upgrade EPJ Web of Conferences |
| title | Machine safety issues with respect to the extension of ECRH systems at ASDEX Upgrade |
| title_full | Machine safety issues with respect to the extension of ECRH systems at ASDEX Upgrade |
| title_fullStr | Machine safety issues with respect to the extension of ECRH systems at ASDEX Upgrade |
| title_full_unstemmed | Machine safety issues with respect to the extension of ECRH systems at ASDEX Upgrade |
| title_short | Machine safety issues with respect to the extension of ECRH systems at ASDEX Upgrade |
| title_sort | machine safety issues with respect to the extension of ecrh systems at asdex upgrade |
| url | http://dx.doi.org/10.1051/epjconf/20158702010 |
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