Deposition in the inner and outer corners of the JET divertor with carbon wall and metallic ITER-like wall

TY - JOUR

T1 - Deposition in the inner and outer corners of the JET divertor with carbon wall and metallic ITER-like wall

AU - Beal, J

AU - Widdowson, A

AU - Heinola, K

AU - Baron-Wiechec, A

AU - Gibson, K J

AU - Coad, J P

AU - Alves, E

AU - Lipschultz, B

AU - Kirschner, A

AU - Esser, H G

AU - Matthews, G F

AU - Brezinsek, S

AU - Contributors, JET

N1 - © 2016 EUROfusion. This is an author-produced version of the published paper. Uploaded in accordance with the publisher’s self-archiving policy. Further copying may not be permitted; contact the publisher for details

PY - 2016/1/21

Y1 - 2016/1/21

N2 - Rotating collectors and quartz microbalances (QMBs) are used in JET to provide time-dependent measurements of erosion and deposition. Rotation of collector discs behind apertures allows recording of the long term evolution of deposition. QMBs measure mass change via the frequency deviations of vibrating quartz crystals. These diagnostics are used to investigate erosion/deposition during JET-C carbon operation and JET-ILW (ITER-like wall) beryllium/tungsten operation. A simple geometrical model utilising experimental data is used to model the time-dependent collector deposition profiles, demonstrating good qualitative agreement with experimental results. Overall, the JET-ILW collector deposition is reduced by an order of magnitude relative to JET-C, with beryllium replacing carbon as the dominant deposit. However, contrary to JET-C, in JET-ILW there is more deposition on the outer collector than the inner. This reversal of deposition asymmetry is investigated using an analysis of QMB data and is attributed to the different chemical properties of carbon and beryllium.

AB - Rotating collectors and quartz microbalances (QMBs) are used in JET to provide time-dependent measurements of erosion and deposition. Rotation of collector discs behind apertures allows recording of the long term evolution of deposition. QMBs measure mass change via the frequency deviations of vibrating quartz crystals. These diagnostics are used to investigate erosion/deposition during JET-C carbon operation and JET-ILW (ITER-like wall) beryllium/tungsten operation. A simple geometrical model utilising experimental data is used to model the time-dependent collector deposition profiles, demonstrating good qualitative agreement with experimental results. Overall, the JET-ILW collector deposition is reduced by an order of magnitude relative to JET-C, with beryllium replacing carbon as the dominant deposit. However, contrary to JET-C, in JET-ILW there is more deposition on the outer collector than the inner. This reversal of deposition asymmetry is investigated using an analysis of QMB data and is attributed to the different chemical properties of carbon and beryllium.

KW - JET

KW - deposition

KW - erosion

KW - tokamak

UR - http://www.scopus.com/inward/record.url?scp=84959893034&partnerID=8YFLogxK

U2 - 10.1088/0031-8949/T167/1/014052

DO - 10.1088/0031-8949/T167/1/014052

M3 - Article

SN - 0031-8949

VL - 2016

JO - Physica Scripta

JF - Physica Scripta

IS - T167

M1 - 014052

ER -