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46 results on '"Hoekzema, J.A."'

3. Design and R&D of an ECRH system on JET

Author

Verhoeven, A.G.A., Bongers, W.A., Elzendoorn, B.S.Q., Graswinckel, M., Hellingman, P., Kooijman, W., Kruijt, O.G., Maagdenberg, J., Ronden, D., Stakenborg, J., Sterk, A.B., Tichler, J., Alberti, S., Henderson, M., Hoekzema, J.A., Fernandez, A., Likin, K., Bruschi, A., Cirant, S., Novak, S., Piosczyk, B., Thumm, M., Guigon, A., Damiani, C., Pamela, J., Kaye, A., Fleming, C., and Zohm, H.

Published
2003
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8. PARAMETER STUDY OF A SCREW-PINCH REACTOR

Author

Bobeldijk, C., primary, Bustraan, M., additional, Damstra, G.C., additional, Franken, W.M.P., additional, Hoekzema, J.A., additional, Nibbelink, H.J. Klein, additional, Klippel, H.Th., additional, van der Laan, P.C.T., additional, Muysken, M., additional, Schuurman, W., additional, and Verschuur, K.A., additional

Published
1976
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12. RESULTS OF SPICA

Author

BOBELDIJK, C., primary, van HEIJNINGEN, R.J.J., additional, HOEKZEMA, J.A., additional, van der LAAN, P.C.T., additional, OEPTS, D., additional, OOMENS, A.A.M., additional, ZWART, J.W.A., additional, BUSCH, P.J., additional, MARIS, D.J., additional, and KOOYMAN, W., additional

Published
1976
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14. Temporal evolution of confined fast-ion velocity distributions measured by collective Thomson scattering in TEXTOR

Author

Nielsen, Stefan Kragh, Bindslev, Henrik, Porte, L., Hoekzema, J.A., Korsholm, Søren Bang, Leipold, Frank, Meo, Fernando, Michelsen, Poul, Michelsen, Susanne, Oosterbeek, J.W., Tsakadze, Erekle, Wassenhove, G. Van, Westerhof, E., Woskov, P., Nielsen, Stefan Kragh, Bindslev, Henrik, Porte, L., Hoekzema, J.A., Korsholm, Søren Bang, Leipold, Frank, Meo, Fernando, Michelsen, Poul, Michelsen, Susanne, Oosterbeek, J.W., Tsakadze, Erekle, Wassenhove, G. Van, Westerhof, E., and Woskov, P.

Abstract

Fast ions created in the fusion processes will provide up to 70% of the heating in ITER. To optimize heating and current drive in magnetically confined plasmas insight into fast-ion dynamics is important. First measurements of such dynamics by collective Thomson scattering (CTS) were recently reported [Bindslev , Phys. Rev. Lett. 97, 205005 2006]. Here we extend the discussion of these results which were obtained at the TEXTOR tokamak. The fast ions are generated by neutral-beam injection and ion-cyclotron resonance heating. The CTS system uses 100-150 kW of 110-GHz gyrotron probing radiation which scatters off the collective plasma fluctuations driven by the fast-ion motion. The technique measures the projected one-dimensional velocity distribution of confined fast ions in the scattering volume where the probe and receiver beams cross. By shifting the scattering volume a number of scattering locations and different resolved velocity components can be measured. The temporal resolution is 4 ms while the spatial resolution is similar to 10 cm depending on the scattering geometry. Fast-ion velocity distributions in a variety of scenarios are measured, including the evolution of the velocity distribution after turnoff of the ion heating. These results are in close agreement with numerical simulations.

Published
2008

15. Neutral beam start-up dynamics on TEXTOR measured by collective Thomson scattering (CTS)

Author

Nielsen, S.K., Bindslev, Henrik, Hoekzema, J.A., Korsholm, S.B., Leipold, F., Meo, F., Michelsen, Poul, Michelsen, S., Oosterbeek, H., Tsakadze, E.L., Westerhof, E., Woskov, P., Nielsen, S.K., Bindslev, Henrik, Hoekzema, J.A., Korsholm, S.B., Leipold, F., Meo, F., Michelsen, Poul, Michelsen, S., Oosterbeek, H., Tsakadze, E.L., Westerhof, E., and Woskov, P.

Published
2007

16. Fast ions in fusion plasmas measured by CTS

Author

Nielsen, S.K., Bindslev, Henrik, Hoekzema, J.A., Korsholm, S.B., Leipold, F., Meo, F., Michelsen, Poul, Michelsen, S., Oosterbeek, H., Tsakadze, Erekle, Westerhof, E., Woskov, P., Nielsen, S.K., Bindslev, Henrik, Hoekzema, J.A., Korsholm, S.B., Leipold, F., Meo, F., Michelsen, Poul, Michelsen, S., Oosterbeek, H., Tsakadze, Erekle, Westerhof, E., and Woskov, P.

Published
2007

17. Fast ion behaviour in TEXTOR measured by collective Thomson scattering (CTS)

Author

Nielsen, S.K., Bindslev, Henrik, Hoekzema, J.A., Korsholm, S.B., Leipold, F., Meo, F., Michelsen, Poul, Michelsen, S., Oosterbeek, H., Rønby, J., Tsakadze, E.L., Westerhof, E., Woskov, P., Nielsen, S.K., Bindslev, Henrik, Hoekzema, J.A., Korsholm, S.B., Leipold, F., Meo, F., Michelsen, Poul, Michelsen, S., Oosterbeek, H., Rønby, J., Tsakadze, E.L., Westerhof, E., and Woskov, P.

Published
2007

18. Fast-ion dynamics in the TEXTOR tokamak measured by collective Thomson scattering

Author

Bindslev, Henrik, Nielsen, Stefan Kragh, Porte, L., Hoekzema, J.A., Korsholm, Søren Bang, Meo, Fernando, Michelsen, Poul, Michelsen, Susanne, Oosterbeek, J.W., Tsakadze, Erekle, Westerhof, E., Woskov, P., Bindslev, Henrik, Nielsen, Stefan Kragh, Porte, L., Hoekzema, J.A., Korsholm, Søren Bang, Meo, Fernando, Michelsen, Poul, Michelsen, Susanne, Oosterbeek, J.W., Tsakadze, Erekle, Westerhof, E., and Woskov, P.

Abstract

The dynamics of fast ion populations in the TEXTOR tokamak are measured by collective Thomson scattering of millimetre wave radiation generated by a gyrotron operated at 110 GHz and 100-150 kW. Temporal evolution of the energetic ion velocity distribution at switch on of neutral beam injection (NBI) and the slowdown after switch off of NBI are measured. The turn on phase of the NBI has, furthermore, been measured in plasmas with a range of electron densities and temperatures. All of these measurements are shown to be in good agreement with simple Fokker-Planck modelling. Bulk ion rotation velocity is also measured.

Published
2007

19. Design of a dedicated ECE diagnostic for feedback control of instabilities by ECRH

Author

Lazaros, A., Oosterbeek, J.W., Bongers, W.A., Classen, I.G.J., Danilov, I., Hoekzema, J.A., Heidinger, R., Graswinckel, M.F., Korsholm, Søren Bang, Krämer-Flecken, A., Kruijt, O.G., Scholten, J., Tito, C., Tsakadze, Erekle, Vaessen, B.C.E., Westerhof, E., Lazaros, A., Oosterbeek, J.W., Bongers, W.A., Classen, I.G.J., Danilov, I., Hoekzema, J.A., Heidinger, R., Graswinckel, M.F., Korsholm, Søren Bang, Krämer-Flecken, A., Kruijt, O.G., Scholten, J., Tito, C., Tsakadze, Erekle, Vaessen, B.C.E., and Westerhof, E.

Published
2007

20. Fast ion dynamics in magnetically confined plasma measured by collective Thomson scattering

Author

Bindslev, Henrik, Nielsen, Stefan Kragh, Korsholm, Søren Bang, Meo, Fernando, Michelsen, Poul, Michelsen, Susanne, Tsakadze, E.L., Woskov, P., Westerhof, E., Hoekzema, J.A., Oosterbeek, J.W., Porte, L., Bindslev, Henrik, Nielsen, Stefan Kragh, Korsholm, Søren Bang, Meo, Fernando, Michelsen, Poul, Michelsen, Susanne, Tsakadze, E.L., Woskov, P., Westerhof, E., Hoekzema, J.A., Oosterbeek, J.W., and Porte, L.

Published
2007

21. Recent fast ion measurements by collective Thomson scattering (CTS) at the TEXTOR tokamak

Author

Kawahatqa, K., Nielsen, Stefan Kragh, Bindslev, Henrik, Hoekzema, J.A., Korsholm, Søren Bang, Leipold, Frank, Meo, Fernando, Michelsen, Poul, Oosterbeek, H., Westerhof, E., Woskov, P., Kawahatqa, K., Nielsen, Stefan Kragh, Bindslev, Henrik, Hoekzema, J.A., Korsholm, Søren Bang, Leipold, Frank, Meo, Fernando, Michelsen, Poul, Oosterbeek, H., Westerhof, E., and Woskov, P.

Published
2007

22. Design of a dedicated ECE diagnostic for feedback control of instabilities by ECRH (poster)

Author

Oosterbeek, J.W., Bongers, W.A., Classen, I.G.J., Danilov, I., Hoekzema, J.A., Heidinger, R., Graswinckel, M.F., Korsholm, Søren Bang, Kramer-Flecken, A., Kruijt, O.G., Scholten, J., Tito, C., Tsakadze, E., Vaessen, B.C.E., Westerhof, E., Oosterbeek, J.W., Bongers, W.A., Classen, I.G.J., Danilov, I., Hoekzema, J.A., Heidinger, R., Graswinckel, M.F., Korsholm, Søren Bang, Kramer-Flecken, A., Kruijt, O.G., Scholten, J., Tito, C., Tsakadze, E., Vaessen, B.C.E., and Westerhof, E.

Published
2006

23. Fast ion millimeter wave CTS diagnostics on TEXTOR and ASDEX upgrade (poster)

Author

Michelsen, S., Bindslev, H., Egedal, J., Hoekzema, J.A., Korsholm, Søren Bang, Leuterer, F., Meo, F., Michelsen, Poul, Nielsen, S.K., Tsakadze, E.L., Westerhof, E., Woskov, P., Michelsen, S., Bindslev, H., Egedal, J., Hoekzema, J.A., Korsholm, Søren Bang, Leuterer, F., Meo, F., Michelsen, Poul, Nielsen, S.K., Tsakadze, E.L., Westerhof, E., and Woskov, P.

Published
2004

24. Fast ion millimeter wave collective Thomson scattering diagnostics on TEXTOR and ASDEX upgrades

Author

Michelsen, S., Korsholm, Søren Bang, Bindslev, H., Meo, F., Michelsen, Poul, Tsakadze, E.L., Egedal, J., Woskov, P., Hoekzema, J.A., Leuterer, F., Westerhof, E., Michelsen, S., Korsholm, Søren Bang, Bindslev, H., Meo, F., Michelsen, Poul, Tsakadze, E.L., Egedal, J., Woskov, P., Hoekzema, J.A., Leuterer, F., and Westerhof, E.

Abstract

Collective Thomson scattering (CTS) diagnostic systems for measuring fast ions in TEXTOR and ASDEX Upgrade are described in this article. Both systems use millimeter waves generated by gyrotrons as probing radiation and the scattered radiation is detected with heterodyne receivers having 40 spectral channels at TEXTOR and 50 spectral channels at ASDEX Upgrade. The antenna patterns of probe and receiver, both steerable, determine size and location of the measuring volume, and the direction of the resolved fast ion velocity. With overmoded transmission lines, consisting of waveguides and quasioptical mirrors, the antenna patterns depend on the alignment of the entire transmission line. Alignment is aided by visible laser beams relayed by small optical mirrors, inserted in the quasioptical mirrors. (C) 2004 American Institute of Physics.

Published
2004

25. Fast ion millimeter wave CTS diagnostics on TEXTOR and ASDEX upgrade

Author

Michelsen, S., Bindslev, H., Egedal, J., Hoekzema, J.A., Korsholm, Søren Bang, Leuterer, F., Meo, F., Michelsen, Poul, Tsakadze, E.L., Westerhof, E., Woskov, P., Michelsen, S., Bindslev, H., Egedal, J., Hoekzema, J.A., Korsholm, Søren Bang, Leuterer, F., Meo, F., Michelsen, Poul, Tsakadze, E.L., Westerhof, E., and Woskov, P.

Published
2004

28. Electron cyclotron resonance heating on TEXTOR: Results from the preliminary 110 GHz system

Author

Westerhof, E., Hogeweij, G.M.D., Hoekzema, J.A., Schüller, F.C., Barth, C.J., Bindslev, H., Donné, A.J.H., Dumortier, P., Gorkom, J.V. van, Jaspers, R.J.E., Kalupin, D., Koslowski, H.R., Krämer-Flecken, A., Cardozo, N.J.L., Meiden, H.J. vander, Messiaen, A., Oyevaar, T., Polman, R.W., Porte, L., Udintsev, V.S., Unterberg, B., Vervier, M., Eester, D. van, Wassenhove, G. van, Westerhof, E., Hogeweij, G.M.D., Hoekzema, J.A., Schüller, F.C., Barth, C.J., Bindslev, H., Donné, A.J.H., Dumortier, P., Gorkom, J.V. van, Jaspers, R.J.E., Kalupin, D., Koslowski, H.R., Krämer-Flecken, A., Cardozo, N.J.L., Meiden, H.J. vander, Messiaen, A., Oyevaar, T., Polman, R.W., Porte, L., Udintsev, V.S., Unterberg, B., Vervier, M., Eester, D. van, and Wassenhove, G. van

Published
2003

29. The 113 GHz ECRH system for JET

Author

Verhoeven, A.G.A., Bongers, W.A., Elzendoorn, B.S.Q., Graswinckel, M., Hellingman, P., Kamp, J.J., Kooijman, W., Kruijt, O.G., Maagdenberg, J., Ronden, D., Stakenborg, J., Sterk, A.B., Tichler, J., Alberti, S., Goodman, T., Henderson, M., Hoekzema, J.A., Oosterbeek, J.W., Fernandez, A., Likin, K., Bruschi, A., Cirant, S., Novak, S., Piosczyk, B., Thumm, M., Bindslev, H., Kaye, A., Fleming, C., Zohm, H., Verhoeven, A.G.A., Bongers, W.A., Elzendoorn, B.S.Q., Graswinckel, M., Hellingman, P., Kamp, J.J., Kooijman, W., Kruijt, O.G., Maagdenberg, J., Ronden, D., Stakenborg, J., Sterk, A.B., Tichler, J., Alberti, S., Goodman, T., Henderson, M., Hoekzema, J.A., Oosterbeek, J.W., Fernandez, A., Likin, K., Bruschi, A., Cirant, S., Novak, S., Piosczyk, B., Thumm, M., Bindslev, H., Kaye, A., Fleming, C., and Zohm, H.

Published
2003

32. The design of an ECRH system for JET-EP

Author

Verhoeven, A.G.A, primary, Bongers, W.A, additional, Elzendoorn, B.S.Q, additional, Graswinckel, M, additional, Hellingman, P, additional, Kooijman, W, additional, Kruijt, O.G, additional, Maagdenberg, J, additional, Ronden, D, additional, Stakenborg, J, additional, Sterk, A.B, additional, Tichler, J, additional, Alberti, S, additional, Goodman, T, additional, Henderson, M, additional, Hoekzema, J.A, additional, Oosterbeek, J.W, additional, Fernandez, A, additional, Likin, K, additional, Bruschi, A, additional, Cirant, S, additional, Novak, S, additional, Piosczyk, B, additional, Thumm, M, additional, Bindslev, H, additional, Kaye, A, additional, Fleming, C, additional, and Zohm, H, additional

Published
2003
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33. Electron cyclotron resonance heating on TEXTOR

Author

Westerhof, E, primary, Hoekzema, J.A, additional, Hogeweij, G.M.D, additional, Jaspers, R.J.E, additional, Schüller, F.C, additional, Barth, C.J, additional, Bongers, W.A, additional, Donné, A.J.H, additional, Dumortier, P, additional, Grift, A.F. van der, additional, Gorkom, J.C. van, additional, Kalupin, D, additional, Koslowski, H.R, additional, Krämer-Flecken, A, additional, Kruijt, O.G, additional, Cardozo, N.J. Lopes, additional, Mantica, P, additional, Meiden, H.J. van der, additional, Merkulov, A, additional, Messiaen, A, additional, Oosterbeek, J.W, additional, Oyevaar, T, additional, Poelman, A.J, additional, Polman, R.W, additional, Prins, P.R, additional, Scholten, J, additional, Sterk, A.B, additional, Tito, C.J, additional, Udintsev, V.S, additional, Unterberg, B, additional, Vervier, M, additional, Wassenhove, G. van, additional, and Team, TEC, additional

Published
2003
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34. The 113 GHz ECRH system for JET

Author

Verhoeven, A.G.A., primary, Bongers, W.A., additional, Elzendoorn, B.S.Q., additional, Graswinckel, M., additional, Hellingman, P., additional, Kamp, J.J., additional, Kooijman, W., additional, Kruijt, O.G., additional, Maagdenberg, J., additional, Ronden, D., additional, Stakenborg, J., additional, Sterk, A.B., additional, Tichler, J., additional, Alberti, S., additional, Goodman, T., additional, Henderson, M., additional, Hoekzema, J.A., additional, Oosterbeek, J.W., additional, Fernandez, A., additional, Likin, K., additional, Bruschi, A., additional, Cirant, S., additional, Novak, S., additional, Piosczyk, B., additional, Thumm, M., additional, Bindslev, H., additional, Kaye, A., additional, Fleming, C., additional, and Zohm, H., additional

Published
2003
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36. A collective scattering diagnostic to measure fast-ion and alpha-particle distributions in JET

Author

Costley, A.E., Bindslev, H., Comisky, M., Fessey, J., Hammond, N., Hoekzema, J.A., Hughes, T.P., Machuzak, J., Roberts, P., Stevens, A., Stott, P.E., Taylor, E., Woskov, P., Costley, A.E., Bindslev, H., Comisky, M., Fessey, J., Hammond, N., Hoekzema, J.A., Hughes, T.P., Machuzak, J., Roberts, P., Stevens, A., Stott, P.E., Taylor, E., and Woskov, P.

Published
1992

37. Fast particle diagnostics at JET: status and plans

Author

Sadler, G.J, primary, Adams, J.M, additional, Cecil, F.E, additional, Cottrell, G.A, additional, Gondhalekar, A, additional, Hoekzema, J.A, additional, Jarvis, O.N, additional, Loughlin, M.J, additional, Marcus, F.B, additional, Belle, P. Van, additional, and Hellermann, M. Von, additional

Published
1995
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38. Linewidth measurements of the JET energetic ion and alpha particle collective Thomson scattering...

Author

Machuzak, John S., Woskov, Paul P., Fessey, John A., Hoekzema, J.A., Egedal, Jan, Bindslev, Henrik, Roberts, Peter, Stevens, Andrew, Davies, Paul, Gatcombe, Christopher, and Hughes, Thomas P.

Subjects
SPECTRAL energy distribution, THOMSON scattering, GYROTRONS
Abstract

Determines the linewidth measurements of the Joint European Torus energetic ion and alpha particle collective Thomson scattering (CTS) diagnostic gyrotron. Use of the CTS diagnostic receiver system to make measurements; Composition of the system; Homodyne receiver and main receiver measurements; Gyrotron frequency offset range.

Published
1999
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39. Electron Cyclotron Waves

Author

Hoekzema, J.A.

Abstract

An introduction is given to plasma heating and current drive with electromagnetic waves in the electron cyclotron range of frequencies, with emphasis on application in tokamak plasmas. Propagation and absorption of these waves is generally well described by linear theory, a short overview of which is given. Electron cyclotron absorption is limited to regions of the plasma where the gyromotion of electrons is in resonance with the wave frequency and can be well localised, even in smaller experiments. Apart from being able to provide global heating and non-inductive current drive, ECRH and ECCD are therefore important tools to study and manipulate locally instabilities in the plasma which are electron temperature gradient or current driven. Important potential control applications in a reactor grade plasma include mode stabilisation to prevent disruptions, transport manipulation (e.g. to maintain burn) and correction of the bootstrap current profile. The use of EC waves in major tokamak experiments has in the past been restricted due to the lack of suitable sources. These sources are, however, now rapidly becoming available.

Published
2002
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40. SPICA

Author

Bobeldijk, C., Van Heesch, E.J.M., Hoekzema, J.A., Van Der Meer, A.F.G., Oepts, D., and Oomens, A.A.M.

Abstract

The major experimental results on low-q, high-beta plasmas obtained in the circular and non-circular versions of SPICA and its predecessors are summarized.

Published
1985
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41. Prospects for SPICA II

Author

Brakel, van, R.L., Oomens, A.A.M., Bobeldijk, C., Busch, P.J., Dijk, van, G., Geer, van der, C.A.J., Grobben, B.J.J., Heesch, van, E.J.M., Hoekzema, J.A., Kooijman, W., Cardozo, Lopes, N.J., Mastop, W.J.M., Pulsed corona, and Electrical Energy Systems

Subjects
Nuclear physics, Physics, Cross section (physics), Toroid, General Engineering, Pinch, Plasma diagnostics, Spica
Abstract

A description is given of the experiment SPICA II, a toroidal screw pinch with non-circular cross section. On the basis of model calculations and experience with past screw-pinch experiments the expected performance of this machine is discussed. A survey is given of the planned diagnostics.

Published
1983

43. The ECW system on TEXTOR

Author

Hoekzema, J.A., primary, Bongers, W.A., additional, van der Grift, A.F., additional, Kruije, O.G., additional, Oosterbeek, J.W., additional, Poelman, A.J., additional, Prins, P.R., additional, Scholten, J., additional, Schuller, F.C., additional, Sterk, A.B., additional, Tito, C.J., additional, and Westerhoe, E., additional

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44. Design of an ECRH system for JET

Author

Verhoeven, A.G.A., primary, Bongers, W.A., additional, Elzendoorn, B.S.Q., additional, Graswinckel, M., additional, Hellingman, P., additional, Kooijman, W., additional, Kruijt, O.G., additional, Maagdenberg, J., additional, Ronden, D., additional, Stakenborg, J., additional, Sterk, A.B., additional, Tichler, J., additional, Alberti, S., additional, Henderson, M., additional, Hoekzema, J.A., additional, Fernandez, A., additional, Likin, K., additional, Bruschi, A., additional, Cirant, S., additional, Novak, S., additional, Piosczyk, B., additional, Thumm, M., additional, Guigon, A., additional, Damiani, C., additional, Pamela, J., additional, Kaye, A., additional, Fleming, C., additional, and Zohm, H., additional

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45. Design of an ECRH system for JET.

Author

Verhoeven, A.G.A., Bongers, W.A., Elzendoorn, B.S.Q., Graswinckel, M., Hellingman, P., Kooijman, W., Kruijt, O.G., Maagdenberg, J., Ronden, D., Stakenborg, J., Sterk, A.B., Tichler, J., Alberti, S., Henderson, M., Hoekzema, J.A., Fernandez, A., Likin, K., Bruschi, A., Cirant, S., and Novak, S.

Published
2002
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46. The ECW system on TEXTOR.

Author

Hoekzema, J.A., Bongers, W.A., van der Grift, A.F., Kruije, O.G., Oosterbeek, J.W., Poelman, A.J., Prins, P.R., Scholten, J., Schuller, F.C., Sterk, A.B., Tito, C.J., and Westerhoe, E.

Published
2002
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