Plasma wall interaction and its implication in an all tungsten divertor tokamak

R. Neu, M. Balden, V. Bobkov, R. Dux, O. Gruber, A. Herrmann, A. Kallenbach, M. Kaufmann, C. F. Maggi, H. Maier, H. W. Müller, T. Pütterich, R. Pugno, V. Rohde, A. C.C. Sips, J. Stober, W. Suttrop, C. Angioni, C. V. Atanasiu, W. BeckerK. Behler, K. Behringer, A. Bergmann, T. Bertoncelli, R. Bilato, A. Bottino, M. Brambilla, F. Braun, A. Buhler, A. Chankin, G. Conway, D. P. Coster, P. De Marné, S. Dietrich, K. Dimova, R. Drube, T. Eich, K. Engelhardt, H. U. Fahrbach, U. Fantz, L. Fattorini, J. Fink, R. Fischer, A. Flaws, P. Franzen, J. C. Fuchs, K. Gàl, M. García Mũoz, M. Gemisic-Adamov, J. Likonen

    Research output: Contribution to journalArticleScientificpeer-review

    110 Citations (Scopus)

    Abstract

    ASDEX Upgrade has recently finished its transition towards an all-W divertor tokamak, by the exchange of the last remaining graphite tiles to W-coated ones. The plasma start-up was performed without prior boronization. It was found that the large He content in the plasma, resulting from DC glow discharges for conditioning, leads to a confinement reduction. After the change to D glow for inter-shot conditioning, the He content quickly dropped and, in parallel, the usual H-Mode confinement with H factors close to one was achieved. After the initial conditioning phase, oxygen concentrations similar to that in previous campaigns with boronizations could be achieved. Despite the removal of all macroscopic carbon sources, no strong change in C influxes and C content could be observed so far. The W concentrations are similar to the ones measured previously in discharges with old boronization and only partial coverage of the surfaces with W. Concomitantly it is found that although the W erosion flux in the divertor is larger than the W sources in the main chamber in most of the scenarios, it plays only a minor role for the W content in the main plasma. For large antenna distances and strong gas puffing, ICRH power coupling could be optimized to reduce the W influxes. This allowed a similar increase of stored energy as yielded with comparable beam power. However, a strong increase of radiated power and a loss of H-Mode was observed for conditions with high temperature edge plasma close to the antennas. The use of ECRH allowed keeping the central peaking of the W concentration low and even phases of improved H-modes have already been achieved.

    Original languageEnglish
    JournalPlasma Physics and Controlled Fusion
    Volume49
    Issue number12B
    DOIs
    Publication statusPublished - 14 Nov 2007
    MoE publication typeA1 Journal article-refereed

    Fingerprint

    Beam plasma interactions
    Tungsten
    tungsten
    conditioning
    Plasmas
    antennas
    interactions
    Antennas
    tiles
    power loss
    Glow discharges
    Tile
    glow discharges
    shot
    erosion
    low concentrations
    Erosion
    Graphite
    graphite
    chambers

    Cite this

    Neu, R. ; Balden, M. ; Bobkov, V. ; Dux, R. ; Gruber, O. ; Herrmann, A. ; Kallenbach, A. ; Kaufmann, M. ; Maggi, C. F. ; Maier, H. ; Müller, H. W. ; Pütterich, T. ; Pugno, R. ; Rohde, V. ; Sips, A. C.C. ; Stober, J. ; Suttrop, W. ; Angioni, C. ; Atanasiu, C. V. ; Becker, W. ; Behler, K. ; Behringer, K. ; Bergmann, A. ; Bertoncelli, T. ; Bilato, R. ; Bottino, A. ; Brambilla, M. ; Braun, F. ; Buhler, A. ; Chankin, A. ; Conway, G. ; Coster, D. P. ; De Marné, P. ; Dietrich, S. ; Dimova, K. ; Drube, R. ; Eich, T. ; Engelhardt, K. ; Fahrbach, H. U. ; Fantz, U. ; Fattorini, L. ; Fink, J. ; Fischer, R. ; Flaws, A. ; Franzen, P. ; Fuchs, J. C. ; Gàl, K. ; Mũoz, M. García ; Gemisic-Adamov, M. ; Likonen, J. / Plasma wall interaction and its implication in an all tungsten divertor tokamak. In: Plasma Physics and Controlled Fusion. 2007 ; Vol. 49, No. 12B.
    @article{f6b3359cdb734ab38a34fd30809e223a,
    title = "Plasma wall interaction and its implication in an all tungsten divertor tokamak",
    abstract = "ASDEX Upgrade has recently finished its transition towards an all-W divertor tokamak, by the exchange of the last remaining graphite tiles to W-coated ones. The plasma start-up was performed without prior boronization. It was found that the large He content in the plasma, resulting from DC glow discharges for conditioning, leads to a confinement reduction. After the change to D glow for inter-shot conditioning, the He content quickly dropped and, in parallel, the usual H-Mode confinement with H factors close to one was achieved. After the initial conditioning phase, oxygen concentrations similar to that in previous campaigns with boronizations could be achieved. Despite the removal of all macroscopic carbon sources, no strong change in C influxes and C content could be observed so far. The W concentrations are similar to the ones measured previously in discharges with old boronization and only partial coverage of the surfaces with W. Concomitantly it is found that although the W erosion flux in the divertor is larger than the W sources in the main chamber in most of the scenarios, it plays only a minor role for the W content in the main plasma. For large antenna distances and strong gas puffing, ICRH power coupling could be optimized to reduce the W influxes. This allowed a similar increase of stored energy as yielded with comparable beam power. However, a strong increase of radiated power and a loss of H-Mode was observed for conditions with high temperature edge plasma close to the antennas. The use of ECRH allowed keeping the central peaking of the W concentration low and even phases of improved H-modes have already been achieved.",
    author = "R. Neu and M. Balden and V. Bobkov and R. Dux and O. Gruber and A. Herrmann and A. Kallenbach and M. Kaufmann and Maggi, {C. F.} and H. Maier and M{\"u}ller, {H. W.} and T. P{\"u}tterich and R. Pugno and V. Rohde and Sips, {A. C.C.} and J. Stober and W. Suttrop and C. Angioni and Atanasiu, {C. V.} and W. Becker and K. Behler and K. Behringer and A. Bergmann and T. Bertoncelli and R. Bilato and A. Bottino and M. Brambilla and F. Braun and A. Buhler and A. Chankin and G. Conway and Coster, {D. P.} and {De Marn{\'e}}, P. and S. Dietrich and K. Dimova and R. Drube and T. Eich and K. Engelhardt and Fahrbach, {H. U.} and U. Fantz and L. Fattorini and J. Fink and R. Fischer and A. Flaws and P. Franzen and Fuchs, {J. C.} and K. G{\`a}l and Mũoz, {M. Garc{\'i}a} and M. Gemisic-Adamov and J. Likonen",
    year = "2007",
    month = "11",
    day = "14",
    doi = "10.1088/0741-3335/49/12B/S04",
    language = "English",
    volume = "49",
    journal = "Plasma Physics and Controlled Fusion",
    issn = "0741-3335",
    publisher = "Institute of Physics IOP",
    number = "12B",

    }

    Neu, R, Balden, M, Bobkov, V, Dux, R, Gruber, O, Herrmann, A, Kallenbach, A, Kaufmann, M, Maggi, CF, Maier, H, Müller, HW, Pütterich, T, Pugno, R, Rohde, V, Sips, ACC, Stober, J, Suttrop, W, Angioni, C, Atanasiu, CV, Becker, W, Behler, K, Behringer, K, Bergmann, A, Bertoncelli, T, Bilato, R, Bottino, A, Brambilla, M, Braun, F, Buhler, A, Chankin, A, Conway, G, Coster, DP, De Marné, P, Dietrich, S, Dimova, K, Drube, R, Eich, T, Engelhardt, K, Fahrbach, HU, Fantz, U, Fattorini, L, Fink, J, Fischer, R, Flaws, A, Franzen, P, Fuchs, JC, Gàl, K, Mũoz, MG, Gemisic-Adamov, M & Likonen, J 2007, 'Plasma wall interaction and its implication in an all tungsten divertor tokamak', Plasma Physics and Controlled Fusion, vol. 49, no. 12B. https://doi.org/10.1088/0741-3335/49/12B/S04

    Plasma wall interaction and its implication in an all tungsten divertor tokamak. / Neu, R.; Balden, M.; Bobkov, V.; Dux, R.; Gruber, O.; Herrmann, A.; Kallenbach, A.; Kaufmann, M.; Maggi, C. F.; Maier, H.; Müller, H. W.; Pütterich, T.; Pugno, R.; Rohde, V.; Sips, A. C.C.; Stober, J.; Suttrop, W.; Angioni, C.; Atanasiu, C. V.; Becker, W.; Behler, K.; Behringer, K.; Bergmann, A.; Bertoncelli, T.; Bilato, R.; Bottino, A.; Brambilla, M.; Braun, F.; Buhler, A.; Chankin, A.; Conway, G.; Coster, D. P.; De Marné, P.; Dietrich, S.; Dimova, K.; Drube, R.; Eich, T.; Engelhardt, K.; Fahrbach, H. U.; Fantz, U.; Fattorini, L.; Fink, J.; Fischer, R.; Flaws, A.; Franzen, P.; Fuchs, J. C.; Gàl, K.; Mũoz, M. García; Gemisic-Adamov, M.; Likonen, J.

    In: Plasma Physics and Controlled Fusion, Vol. 49, No. 12B, 14.11.2007.

    Research output: Contribution to journalArticleScientificpeer-review

    TY - JOUR

    T1 - Plasma wall interaction and its implication in an all tungsten divertor tokamak

    AU - Neu, R.

    AU - Balden, M.

    AU - Bobkov, V.

    AU - Dux, R.

    AU - Gruber, O.

    AU - Herrmann, A.

    AU - Kallenbach, A.

    AU - Kaufmann, M.

    AU - Maggi, C. F.

    AU - Maier, H.

    AU - Müller, H. W.

    AU - Pütterich, T.

    AU - Pugno, R.

    AU - Rohde, V.

    AU - Sips, A. C.C.

    AU - Stober, J.

    AU - Suttrop, W.

    AU - Angioni, C.

    AU - Atanasiu, C. V.

    AU - Becker, W.

    AU - Behler, K.

    AU - Behringer, K.

    AU - Bergmann, A.

    AU - Bertoncelli, T.

    AU - Bilato, R.

    AU - Bottino, A.

    AU - Brambilla, M.

    AU - Braun, F.

    AU - Buhler, A.

    AU - Chankin, A.

    AU - Conway, G.

    AU - Coster, D. P.

    AU - De Marné, P.

    AU - Dietrich, S.

    AU - Dimova, K.

    AU - Drube, R.

    AU - Eich, T.

    AU - Engelhardt, K.

    AU - Fahrbach, H. U.

    AU - Fantz, U.

    AU - Fattorini, L.

    AU - Fink, J.

    AU - Fischer, R.

    AU - Flaws, A.

    AU - Franzen, P.

    AU - Fuchs, J. C.

    AU - Gàl, K.

    AU - Mũoz, M. García

    AU - Gemisic-Adamov, M.

    AU - Likonen, J.

    PY - 2007/11/14

    Y1 - 2007/11/14

    N2 - ASDEX Upgrade has recently finished its transition towards an all-W divertor tokamak, by the exchange of the last remaining graphite tiles to W-coated ones. The plasma start-up was performed without prior boronization. It was found that the large He content in the plasma, resulting from DC glow discharges for conditioning, leads to a confinement reduction. After the change to D glow for inter-shot conditioning, the He content quickly dropped and, in parallel, the usual H-Mode confinement with H factors close to one was achieved. After the initial conditioning phase, oxygen concentrations similar to that in previous campaigns with boronizations could be achieved. Despite the removal of all macroscopic carbon sources, no strong change in C influxes and C content could be observed so far. The W concentrations are similar to the ones measured previously in discharges with old boronization and only partial coverage of the surfaces with W. Concomitantly it is found that although the W erosion flux in the divertor is larger than the W sources in the main chamber in most of the scenarios, it plays only a minor role for the W content in the main plasma. For large antenna distances and strong gas puffing, ICRH power coupling could be optimized to reduce the W influxes. This allowed a similar increase of stored energy as yielded with comparable beam power. However, a strong increase of radiated power and a loss of H-Mode was observed for conditions with high temperature edge plasma close to the antennas. The use of ECRH allowed keeping the central peaking of the W concentration low and even phases of improved H-modes have already been achieved.

    AB - ASDEX Upgrade has recently finished its transition towards an all-W divertor tokamak, by the exchange of the last remaining graphite tiles to W-coated ones. The plasma start-up was performed without prior boronization. It was found that the large He content in the plasma, resulting from DC glow discharges for conditioning, leads to a confinement reduction. After the change to D glow for inter-shot conditioning, the He content quickly dropped and, in parallel, the usual H-Mode confinement with H factors close to one was achieved. After the initial conditioning phase, oxygen concentrations similar to that in previous campaigns with boronizations could be achieved. Despite the removal of all macroscopic carbon sources, no strong change in C influxes and C content could be observed so far. The W concentrations are similar to the ones measured previously in discharges with old boronization and only partial coverage of the surfaces with W. Concomitantly it is found that although the W erosion flux in the divertor is larger than the W sources in the main chamber in most of the scenarios, it plays only a minor role for the W content in the main plasma. For large antenna distances and strong gas puffing, ICRH power coupling could be optimized to reduce the W influxes. This allowed a similar increase of stored energy as yielded with comparable beam power. However, a strong increase of radiated power and a loss of H-Mode was observed for conditions with high temperature edge plasma close to the antennas. The use of ECRH allowed keeping the central peaking of the W concentration low and even phases of improved H-modes have already been achieved.

    UR - http://www.scopus.com/inward/record.url?scp=36348999132&partnerID=8YFLogxK

    U2 - 10.1088/0741-3335/49/12B/S04

    DO - 10.1088/0741-3335/49/12B/S04

    M3 - Article

    AN - SCOPUS:36348999132

    VL - 49

    JO - Plasma Physics and Controlled Fusion

    JF - Plasma Physics and Controlled Fusion

    SN - 0741-3335

    IS - 12B

    ER -