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Your search keyword '"Strintzi, D"' showing total 5 results
Start Over Author "Strintzi, D" Publisher kth, fusionsplasmafysik
5 results on '"Strintzi, D"'

1. A Key to Improved Ion Core Confinement in the JET Tokamak : Ion Stiffness Mitigation due to Combined Plasma Rotation and Low Magnetic Shear

Author

Mantica, P., Angioni, C., Challis, C., Colyer, G., Frassinetti, Lorenzo, Hawkes, N., Johnson, Thomas, Tsalas, M., deVries, P. C., Weiland, J., Baiocchi, B., Beurskens, M. N. A., Figueiredo, A. C. A., Giroud, C., Hobirk, J., Joffrin, E., Lerche, E., Naulin, V., Peeters, A. G., Salmi, A., Sozzi, C., Strintzi, D., Staebler, G., Tala, T., Van Eester, D., Versloot, T., Mantica, P., Angioni, C., Challis, C., Colyer, G., Frassinetti, Lorenzo, Hawkes, N., Johnson, Thomas, Tsalas, M., deVries, P. C., Weiland, J., Baiocchi, B., Beurskens, M. N. A., Figueiredo, A. C. A., Giroud, C., Hobirk, J., Joffrin, E., Lerche, E., Naulin, V., Peeters, A. G., Salmi, A., Sozzi, C., Strintzi, D., Staebler, G., Tala, T., Van Eester, D., and Versloot, T.

Abstract

New transport experiments on JET indicate that ion stiffness mitigation in the core of a rotating plasma, as described by Mantica et al. [Phys. Rev. Lett. 102, 175002 (2009)] results from the combined effect of high rotational shear and low magnetic shear. The observations have important implications for the understanding of improved ion core confinement in advanced tokamak scenarios. Simulations using quasilinear fluid and gyrofluid models show features of stiffness mitigation, while nonlinear gyrokinetic simulations do not. The JET experiments indicate that advanced tokamak scenarios in future devices will require sufficient rotational shear and the capability of q profile manipulation., QC 20111017

Published
2011
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2. Ion heat transport studies in JET

Author

Mantica, P., Angioni, C., Baiocchi, B., Baruzzo, M., Beurskens, M. N. A., Bizarro, J. P. S., Budny, R. V., Buratti, P., Casati, A., Challis, C., Citrin, J., Colyer, G., Crisanti, F., Figueiredo, A. C. A., Frassinetti, Lorenzo, Giroud, C., Hawkes, N., Hobirk, J., Joffrin, E., Johnson, Thomas, Lerche, E., Migliano, P., Naulin, V., Peeters, A. G., Rewoldt, G., Ryter, F., Salmi, A., Sartori, R., Sozzi, C., Staebler, G., Strintzi, D., Tala, T., Tsalas, M., Van Eester, D., Versloot, T., de Vries, P. C., Weiland, J., Mantica, P., Angioni, C., Baiocchi, B., Baruzzo, M., Beurskens, M. N. A., Bizarro, J. P. S., Budny, R. V., Buratti, P., Casati, A., Challis, C., Citrin, J., Colyer, G., Crisanti, F., Figueiredo, A. C. A., Frassinetti, Lorenzo, Giroud, C., Hawkes, N., Hobirk, J., Joffrin, E., Johnson, Thomas, Lerche, E., Migliano, P., Naulin, V., Peeters, A. G., Rewoldt, G., Ryter, F., Salmi, A., Sartori, R., Sozzi, C., Staebler, G., Strintzi, D., Tala, T., Tsalas, M., Van Eester, D., Versloot, T., de Vries, P. C., and Weiland, J.

Abstract

Detailed experimental studies of ion heat transport have been carried out in JET exploiting the upgrade of active charge exchange spectroscopy and the availability of multi-frequency ion cyclotron resonance heating with (3)He minority. The determination of ion temperature gradient (ITG) threshold and ion stiffness offers unique opportunities for validation of the well-established theory of ITG driven modes. Ion stiffness is observed to decrease strongly in the presence of toroidal rotation when the magnetic shear is sufficiently low. This effect is dominant with respect to the well-known omega(ExB) threshold up-shift and plays a major role in enhancing core confinement in hybrid regimes and ion internal transport barriers. The effects of T(e)/T(i) and s/q on ion threshold are found rather weak in the domain explored. Quasi-linear fluid/gyro-fluid and linear/non-linear gyro-kinetic simulations have been carried out. Whilst threshold predictions show good match with experimental observations, some significant discrepancies are found on the stiffness behaviour., QC 20120206

Published
2011
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3. Experimental Progress in Rotation Physics towards the Capability to Predict the Toroidal Rotation Profile

Author

Tala, T., Lin, Y., Mantica, P., Nave, M. F. F., Sun, Y., Versloot, T. W., de Vries, P. C., Angioni, C., Asunta, O., Corrigan, G., Giroud, C., Ferreira, J., Hellsten, Torbjörn, Johnson, Thomas, Koslowski, H. R., Lerche, E., Liang, Y., Lönnroth, J., Naulin, V., Peeters, A. G., Rice, J. E., Salmi, A., Solomon, W., Strintzi, D., Tardini, G., Tsalas, M., van Eester, D., Weiland, J., Weisen, H., Zastrow, K.-D., Tala, T., Lin, Y., Mantica, P., Nave, M. F. F., Sun, Y., Versloot, T. W., de Vries, P. C., Angioni, C., Asunta, O., Corrigan, G., Giroud, C., Ferreira, J., Hellsten, Torbjörn, Johnson, Thomas, Koslowski, H. R., Lerche, E., Liang, Y., Lönnroth, J., Naulin, V., Peeters, A. G., Rice, J. E., Salmi, A., Solomon, W., Strintzi, D., Tardini, G., Tsalas, M., van Eester, D., Weiland, J., Weisen, H., and Zastrow, K.-D.

Abstract

QC 20120420

Published
2010

4. Experimental Study of the Ion Critical-Gradient Length and Stiffness Level and the Impact of Rotation in the JET Tokamak

Author

Mantica, P., Strintzi, D., Tala, T., Giroud, C., Johnson, Thomas J., Leggate, H., Lerche, E., Loarer, T., Peeters, A. G., Salmi, A., Sharapov, S., Van Eester, D., de Vries, P. C., Zabeo, L., Zastrow, K. D., Mantica, P., Strintzi, D., Tala, T., Giroud, C., Johnson, Thomas J., Leggate, H., Lerche, E., Loarer, T., Peeters, A. G., Salmi, A., Sharapov, S., Van Eester, D., de Vries, P. C., Zabeo, L., and Zastrow, K. D.

Abstract

Experiments were carried out in the JET tokamak to determine the critical ion temperature inverse gradient length (R/L-Ti = R vertical bar del T-i vertical bar/T-i) for the onset of ion temperature gradient modes and the stiffness of Ti profiles with respect to deviations from the critical value. Threshold and stiffness have been compared with linear and nonlinear predictions of the gyrokinetic code GS2. Plasmas with higher values of toroidal rotation show a significant increase in R/L-Ti, which is found to be mainly due to a decrease of the stiffness level. This finding has implications on the extrapolation to future machines of present day results on the role of rotation on confinement., QC 20100525

Published
2009
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5. Experimental Study of the Ion Critical Gradient Length and Stiffness Level and the Impact of Rotational Shear in the JET Tokamak

Author

Mantica, P., Strintzi, D., Tala, T., Giroud, C., Johnson, Thomas, Leggate, H., Lerche, E., Loarer, T., Peeters, A. G., Salmi, A., Sharapov, S., Van Eester, D., de Vries, P. C., Zabeo, L., Zastrow, K.-D., Mantica, P., Strintzi, D., Tala, T., Giroud, C., Johnson, Thomas, Leggate, H., Lerche, E., Loarer, T., Peeters, A. G., Salmi, A., Sharapov, S., Van Eester, D., de Vries, P. C., Zabeo, L., and Zastrow, K.-D.

Abstract

Experiments have been carried out in the JET tokamak in order to determine the critical iontemperature inverse gradient length (R/LTi =R|∇Ti|/Ti) for the onset of Ion Temperature Gradientmodes and the stiffness of Ti profiles with respect to deviations from the critical value. The existenceof a threshold in R/LTi has been assessed and its value found in close agreement with linear GS2gyro-kinetic calculations. The ion stiffness level is high and keeps R/LTi close to the linear thresholdirrespective of the amount of core ion heating. This finding is not in agreement with non-linear GS2calculations, yielding significantly higher R/LTi values than the linear threshold. Comparison ofplasmas with different values of toroidal rotation indicates a significant increase in R/LTi in rotatingplasmas. Various observations allow to conclude that such increase is mainly due to a decrease ofthe stiffness level with increasing rotation, rather than to a mere up-shift of the threshold, as commonlypredicted by theory. This finding has implications on the interpretation of present day experimentalresults on the effect of rotation on confinement as well as on extrapolations to future machines., QC 20120509

Published
2008

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