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6 results on '"de Bock, M F M"'

1. Transport and divertor properties of the dynamic ergodic divertor

Author

Lehnen, M., Abdullaev, S. S., Jachmich, S., Jakubowski, M. W., Jaspers, R., Koslowski, H. R., Krämer-Flecken, A., Kikuchi, Y., Liang, Y., Loozen, X., Pospieszczyk, A., van Rumpuy, T., Biel, W., Reiter, D., Samm, U., Schmitz, O., Sergienko, G., Tokar, M., Unterberg, B., Wolf, R., Zimmermann, O., de Bock, M. F. M., Brezinsek, S., Busch, C., Classen, I., Finken, K. H., Harting, D., and von Hellermann, M.

Subjects
Physics, Safety factor, Magnetic structure, Divertor, Magnetic confinement fusion, Laminar flow, Plasma, Condensed Matter Physics, Computational physics, Nuclear Energy and Engineering, Physics::Plasma Physics, Electromagnetic coil, ddc:530, Atomic physics, Excitation
Abstract

The concept of the dynamic ergodic divertor (DED) is based on plasma edge ergodization by a resonant perturbation. Such a divertor concept is closely related to helical or island divertors in stellerators. The base mode of the DED perturbation field can be m/n = 12/4, 6/2 or 3/1. The 3/1 base mode with its deep penetration of the perturbation field provides the excitation of tearing modes. This topic was presented elsewhere. In this contribution we concentrate on the divertor properties of the DED. We report on the characterization of the topology, transport properties in ergodic fields, impurity transport and density limit behaviour.The 12/4 base where the perturbation is restricted to the plasma edge is suitable for divertor operation. With increasing perturbation field island chains are built up at the resonance layers. Overlapping islands lead to ergodization. The plasma is guided in the laminar region via open field lines of short connection length to the divertor target. The magnetic topology is not only controlled by the coil current but especially by the edge safety factor. For appropriate edge safety factor we observe a strong temperature drop in the plasma edge, indicating an expansion of the laminar region, which is necessary to decouple the divertor plasma from the core plasma. The modifications of the magnetic topology can be directly seen, for example, from carbon emission lines. The magnetic structure is calculated by the ATLAS code and shows good agreement with the experimental findings.

Published
2005
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2. Overview of physics results from MAST towards ITER/DEMO and the MAST Upgrade

Author

Meyer, H., Abel, I. G., Akers, R. J., Allan, A., Allan, S. Y., Appel, L., Asunta, O., Barnes, M., Barratt, N. C., Ben Ayed, N., Rozhansky, V., Warder, S. E. V., Wilson, H. R., Wodniak, I., Cahyna, P., The MAST Team, Cecconello, M., Challis, C. D., Chapman, I. T., Ciric, D., Colyer, G., Dura, P., Conway, N. J., Fishpool, G., Cox, M., Crowley, B. J., Cowley, S. C., Cunningham, G., Danilov, A., Darke, A., De Bock, M. F. M., De Temmerman, G., Elmore, S., Dendy, R. O., Denner, P., Freethy, S., Dickinson, D., Dnestrovsky, A. Y., Dnestrovsky, Y., Driscoll, M. D., Dudson, B., Dunai, D., Dunstan, M., Field, A. R., Fundamenski, W., Garzotti, L., Ghim, Y. C., Gibson, K. J., Gryaznevich, M. P., Harrison, J., Havlíčková, E., Leggate, H. J., Hawkes, N. C., Lisgo, S. W., Heidbrink, W. W., Hender, T. C., Highcock, E., Higgins, D., Hill, P., Hnat, B., Hole, Matthew, Horáček, J., Liang, Y., Howell, D. F., Imada, K., Liu, Y. Q., Jones, O. M., Kaveeva, E., Keeling, D., Kirk, A., Kočan, M., Lake, R. J., Lehnen, M., Lilley, M. K., Lloyd, B., Maddison, G. P., Mailloux, J., Martin, R., McArdle, G. J., McClements, H. G., McMillan, B., Roach, C. M., Michael, C., Saarelma, S., Militello, F., Molchanov, P., Mordijck, S., Morgan, T., Morris, A. W., Muir, D. G., Nardon, E., Naulin, V., Robinson, J. R., Naylor, G., Nielsen, A. H., Sangaroon, S., O'Brien, M. R., O'Gorman, T., Pamela, S., Parra, F. I., Patel, A., Pinches, S. D., Price, M. N., Romanelli, M., Saveliev, A., Scannell, R., Seidl, J., Sharapov, Sergei, Schekochihin, A. A., Shevchenko, V., Shibaev, S., Zoletnik, S., Bradley, J. W., Stork, D., Storrs, J., Sykes, A., Tallents, G. J., Tamain, P., Taylor, D., Temple, D., Thomas-Davies, N., Thornton, A., Zagôrski, R., Turnyanskiy, M., Canik, J., Valovič, M., Vann, R. G. L., Verwichte, E., Voskoboynikov, P., Voss, G., Meyer, H., Abel, I. G., Akers, R. J., Allan, A., Allan, S. Y., Appel, L., Asunta, O., Barnes, M., Barratt, N. C., Ben Ayed, N., Rozhansky, V., Warder, S. E. V., Wilson, H. R., Wodniak, I., Cahyna, P., The MAST Team, Cecconello, M., Challis, C. D., Chapman, I. T., Ciric, D., Colyer, G., Dura, P., Conway, N. J., Fishpool, G., Cox, M., Crowley, B. J., Cowley, S. C., Cunningham, G., Danilov, A., Darke, A., De Bock, M. F. M., De Temmerman, G., Elmore, S., Dendy, R. O., Denner, P., Freethy, S., Dickinson, D., Dnestrovsky, A. Y., Dnestrovsky, Y., Driscoll, M. D., Dudson, B., Dunai, D., Dunstan, M., Field, A. R., Fundamenski, W., Garzotti, L., Ghim, Y. C., Gibson, K. J., Gryaznevich, M. P., Harrison, J., Havlíčková, E., Leggate, H. J., Hawkes, N. C., Lisgo, S. W., Heidbrink, W. W., Hender, T. C., Highcock, E., Higgins, D., Hill, P., Hnat, B., Hole, Matthew, Horáček, J., Liang, Y., Howell, D. F., Imada, K., Liu, Y. Q., Jones, O. M., Kaveeva, E., Keeling, D., Kirk, A., Kočan, M., Lake, R. J., Lehnen, M., Lilley, M. K., Lloyd, B., Maddison, G. P., Mailloux, J., Martin, R., McArdle, G. J., McClements, H. G., McMillan, B., Roach, C. M., Michael, C., Saarelma, S., Militello, F., Molchanov, P., Mordijck, S., Morgan, T., Morris, A. W., Muir, D. G., Nardon, E., Naulin, V., Robinson, J. R., Naylor, G., Nielsen, A. H., Sangaroon, S., O'Brien, M. R., O'Gorman, T., Pamela, S., Parra, F. I., Patel, A., Pinches, S. D., Price, M. N., Romanelli, M., Saveliev, A., Scannell, R., Seidl, J., Sharapov, Sergei, Schekochihin, A. A., Shevchenko, V., Shibaev, S., Zoletnik, S., Bradley, J. W., Stork, D., Storrs, J., Sykes, A., Tallents, G. J., Tamain, P., Taylor, D., Temple, D., Thomas-Davies, N., Thornton, A., Zagôrski, R., Turnyanskiy, M., Canik, J., Valovič, M., Vann, R. G. L., Verwichte, E., Voskoboynikov, P., and Voss, G.

Abstract

New diagnostic, modelling and plant capability on the Mega Ampère Spherical Tokamak (MAST) have delivered important results in key areas for ITER/DEMO and the upcoming MAST Upgrade, a step towards future ST devices on the path to fusion currently under p

Published
2013

3. L-H transition and pedestal studies on MAST

Author

Meyer, H, De Bock, M F M, Conway, N J, Freethy, S, Gibson, K J, Hiratsuka, J., Kirk, A., Michael, Clive, Morgan, T., Scannell, R, Naylor, G, Saarelma, S., Saveliev, A, Shevchenko, V, Suttrop, W., Temple, D., Vann, R G L, MAST Team, The, Meyer, H, De Bock, M F M, Conway, N J, Freethy, S, Gibson, K J, Hiratsuka, J., Kirk, A., Michael, Clive, Morgan, T., Scannell, R, Naylor, G, Saarelma, S., Saveliev, A, Shevchenko, V, Suttrop, W., Temple, D., Vann, R G L, and MAST Team, The

Abstract

On MAST studies of the profile evolution of the electron temperature (Te), electron density (ne), radial electric field (Er) as well as novel measurements of the ion temperature (Ti) and toroidal current density (jø) in the pedestal region allow further

Published
2011

5. Measurements of the edge current evolution and comparison with neoclassical calculations during MAST H-modes using motional Stark effect.

Author

De Bock, M. F. M., Citrin, J., Saarelma, S., Temple, D., Conway, N. J., Kirk, A., Meyer, H., and Michael, C. A.

Subjects
*STARK effect, *FUSION reactors, *PLASMA gases, *DENSITY currents, *TEMPERATURE, *SELF-consistent field theory, *STABILITY (Mechanics)
Abstract

Edge localized modes (ELMs), that are present in most tokamak H- (high confinement) modes, can cause significant damage to plasma facing components in fusion reactors. Controlling ELMs is considered necessary and hence it is vital to understand the underlying physics. The stability of ELMs is typically expressed in terms of the pressure gradient [?]p in the edge and the edge current density jph. Both [?]p and jph are usually derived from profiles fitted to the measured edge density and temperature profiles, where for the calculation of jph neoclassical theory is used.This paper presents direct measurements of the magnetic pitch angle gm evolution in the edge and the derived jph. These provide a method to validate the jph as derived with neoclassical theory and they open up the possibility to find a complete, self-consistent set of edge profiles, that fit density, temperature and gm measurements, hence allowing for a more accurate stability analysis. [ABSTRACT FROM AUTHOR]

Published
2012
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6. Experimental and theoretical analyses of penetration processes of externally applied rotating helical magnetic perturbation fields in TEXTOR and HYBTOK-II.

Author

Kikuchi, Y., de Bock, M. F. M., Finken, K. H., Jakubowski, M., Jaspers, R., Koslowski, H. R., Kraemer-Flecken, A., Lehnen, M., Liang, Y., Loewenbrueck, K., Matsunaga, G., Reiser, D., Samm, U., Sewell, G., Takamura, S., Unterberg, B., Wolf, R. C., Zimmermann, O., and TEXTOR-team, the

Abstract

Penetration processes of rotating helical magnetic perturbation field into tokamak plasmas have been investigated by the dynamic ergodic divertor (DED) in TEXTOR. Experimental observations of the field penetration and field amplification are performed and the data are interpreted by theoretical analyses based on a linearized two-fluid plasma model. It is observed that the growth of the forced magnetic reconnection by the rotating DED-field is accompanied by a change in the plasma fluid rotation. The theoretical model is also applied to the DED experiment in the small tokamak device HYBTOK-II. It is confirmed that the theoretical analyses can explain the observed radial profiles of the DED-field in the plasma by inserting small magnetic pick-up coils in HYBTOK-II. [ABSTRACT FROM AUTHOR]

Published
2007
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