Confinement and heating of a deuterium-tritium plasma

Hawryluk, R. J.; Adler, H.; Alling, P.; Ancher, C.; Anderson, H.; Anderson, James L.; Ashcroft, D.; Barnes, Cris W.; Barnes, G.; Batha, S. H.; Bell, M.G.; Bell, R. E.; Bitter, M.; Blanchard, W.; Bretz, N.; Budny, R.; Bush, C. E.; Camp, Roderic Ai; Caorlin, M.; Cauffman, Steve; Chang, Z.; Cheng, C. Z.; Collins, J.; Coward, G.; Darrow, D. S.; DeLooper, John; Duong, H. H.; Dudek, L.; Durst, R.; Efthimion, P. C.; Ernst, D. R.; Fisher, R. K.; Fonck, R.J.; Fredrickson, E. D.; Fromm, N.; Fu, G. Y.; Furth, H. P.; Gentile, C.; Gorelenkov, N. N.; Grek, B.; Grisham, L. R.; Hammett, G. W.; Hanson, G. R.; Heidbrink, W. W.; Herrmann, H. W.; Hill, K. W.; Hosea, J.; Hsuan, H.; Janos, A.; Jassby, D.L.; Jobes, F. C.; Johnson, D.; Johnson, L. C.; Kamperschroer, J.; Kugel, H.; Lâm, Nguyễn Thanh; LaMarche, P. H.; Loughlin, M.; LeBlanc, B.; Leonard, M.; Levinton, F. M.; Machuzak, J. S.; Mansfield, D. K.; Martin, Alex; Mazzucato, E.; Majeski, R.; Marmar, E.; McChesney, J. M.; McCormack, B.; McCune, D.; McGuire, K.; McKee, G. W.; Meade, D. M.; Medley, S. S.; Mikkelsen, D. R.; Mueller, D.; Murakami, M.; Nagy, A.; Nazikian, R.; Newman, R.; Nishitani, T.; Norris, M. K. Gaedeke; O'Connor, T.; Oldaker, M.; Osakabe, M.; Owens, D. K.; Park, H.; Park, W.; Paul, S. F.; Pearson, Gavin; Perry, E.; Петров, М. П.; Phillips, C. K.; Pitcher, S.; Ramsey, A. T.; Rasmussen, D. A.; Redi, M. H.; Roberts, D.; Rogers, J. H.; Rossmassler, R.; Roquemore, A. L.; Ruskov, E.; Sabbagh, S. A.; Sasao, M.; Schilling, G.; Schivell, J.; Schmidt, G. L.; Scott, S.D.; Sissingh, R.A.P.; Skinner, C.H.; Snipes, J. A.; Stevens, J.; Stevenson, T. N.; Stratton, B. C.; Strachan, J.D.; Synakowski, E. J.; Tang, W. M.; Taylor, G.; Terry, J. L.; Thompson, Mark E.; Tuszewski, M.; Vannoy, C.; Halle, A. von; Goeler, S. von; Voorhees, D.; Walters, R.T.; Wieland, R.; Wilgen, J. B.; Williams, M. D.; Wilson, J. R.; Wong, K. L.; Wurden, G. A.; Yamada, Masaaki; Young, K. M.; Zarnstorff, M. C.; Zweben, S. J.

doi:10.1103/physrevlett.72.3530

Cited by 94 publications

(16 citation statements)

References 8 publications

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“…Diagnostic inconsistencies on the T i measurements could then be ruled out. Following earlier results from the Tokamak Fusion Test Reactor (TFTR) [17], an isotopic effect on the energy confinement, heat transport and electron temperature was also considered [18][19][20][21][22][23]. However, since the T i and T e increase was measured to be similar and not significant at the two extremes of the DT mixture ratio scan (n T /(n D + n T ) = 0, as in the comparison discharges with ICRF heating, and n T /(n D + n T ) = 0.92), possible isotopic effects in the energy confinement and electron-ion equipartition had to also be excluded as the dominant reason for the observed T i0 increase.…”

Section: The Anomalous Ion Heating Observed In the Jet Dte1 Experimentsmentioning

confidence: 99%

A phenomenological explanation for the anomalous ion heating observed in the JET alpha-heating experiment of 1997

Testa¹,

Albergante²

2012

Nucl. Fusion

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In the so-called 'alpha-heating' experiment performed on the JET tokamak during the deuterium-tritium campaign of 1997, the ion temperature was found to be far exceeding (both in absolute value and in its rise time) the level that could have been expected from direct collisional heating by the fusion-born alpha particles themselves and energy equipartition with the electrons. To date, no explanation has been put forward for this long standing puzzle, despite much work having been performed on this subject in the early 2000s.Two analysis methods that have recently become available have been employed to re-analyse these observations of an anomalous ion heating. First, an algorithm based on the sparse representation of signals has been used to analyse magnetic, reflectometry and electron-cyclotron emission measurements of the turbulence spectra in the drift-wave range of frequencies. This analysis has then been complemented with turbulence simulations performed with the GENE code.We find, both experimentally and in the simulations, that the presence of a minority, but sufficiently large, population of fusion-born alpha particles that have not yet fully thermalized stabilizes the turbulence in the ion-drift direction, but practically does not affect the turbulence in the electron-drift direction. We link such stabilization of the ion-drift-wave turbulence to the increase in the ion temperature above the level achieved in similar discharges that did not have (at all or enough) alpha particles. When the fusion-born alpha particles have fully thermalized, the turbulence spectrum in the ion-drift direction reappears at somewhat larger amplitudes, which we link to the ensuing reduction in the ion temperature. This phenomenological dynamics fully corresponds to the actual experimental observations. By taking into account an effect of the alpha particles that had not been previously considered, our new analysis finally presents a phenomenological explanation for the so-far-unexplained anomalous ion heating observed in the JET alpha-heating experiment of 1997.Through the formulation of an empirical criterion for ion-drift-wave turbulence stabilization by fusion-born alpha particles, we also show why similar observations were not made in the other deuterium-tritium experiments run so far in JET and TFTR. This allows assessing the operational domain for this stabilization mechanism for ion-drift-wave turbulence in future burning plasma experiments such as ITER, which may open a new path towards the sustainment of a high energy gain in such forthcoming devices.

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Section: The Anomalous Ion Heating Observed In the Jet Dte1 Experimentsmentioning

confidence: 99%

A phenomenological explanation for the anomalous ion heating observed in the JET alpha-heating experiment of 1997

Testa¹,

Albergante²

2012

Nucl. Fusion

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“…[1] and references therein). Therefore, dedicated alpha-particle studies were undertaken in past D-T experiments on the Tokamak Fusion Test Reactor and the Joint European Torus (JET) [2,3]. Further alpha-particle physics studies are planned in the forthcoming D-T campaign in JET with the ITER-like wall (JET-ILW) [4].…”

Section: Introductionmentioning

confidence: 99%

Excitation of Alfvén eigenmodes by fusion-born alpha-particles in D-³He plasmas on JET

Kiptily

Kazakov²,

Nocente

et al. 2022

Plasma Phys. Control. Fusion

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Alfvén eigenmode (AE) instabilities driven by alpha-particles have been observed in D-3He fusion experiments on the Joint European Torus (JET) with the ITER-like wall (ILW). For the efficient generation of fusion alpha-particles from D-3He fusion reaction, the 3-ion radio frequency (RF) scenario was used to accelerate the neutral beam injection 100-keV deuterons to higher energies in the core of mixed D-3He plasmas at high concentrations of 3He. A large variety of fast-ion driven magnetohydrodynamic (MHD) modes were observed, including the elliptical Alfvén eigenmodes (EAEs) with mode numbers n=-1 and axisymmetric modes with n=0 in the frequency range of EAEs. The simultaneous observation of these modes indicates the presence of rather strong alpha-particle population in the plasma with a “bump-on-tail” shaped velocity distribution. Linear stability analysis and Fokker Plank calculations support the observations.- Experimental evidence of the AEs excitation by fusion-born alpha-particles in the D-3He plasma is provided by neutron and gamma-ray diagnostics as well as fast-ion loss measurements. We discuss an experimental proposal for the planned full-scale D-T plasma experiments on JET based on the physics insights gained from these experiments.

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“…Alpha heating is essential for practical energy production from deuterium-tritium (DT) fusion reactions. Experiments to detect alpha heating were performed in the tokamak fusion test reactor (TFTR) in 1994 [1,2] and in the Joint European Torus (JET) in 1997 [3,4]. The TFTR results were claimed to be consistent with alpha particle heating of electrons.…”

Section: Introductionmentioning

confidence: 99%

Alpha heating and isotopic mass effects in JET plasmas with sawteeth

Budny

Contributors²

2016

Nucl. Fusion

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The alpha heating experiment in the Joint European Torus (JET) 1997 DTE1 campaign is re-examined. Several effects correlated with tritium content and thermal hydrogenic isotopic mass < A > weaken the conclusion that alpha heating was clearly observed. These effects delayed the occurrence of significant sawtooth crashes allowing the electron and ion temperatures T e and T i to achieve higher values. Under otherwise equal circumstances T e and T i were typically higher for discharges with higher < A >, and significant scaling of T i, T e, and total stored energy with < A > were observed. The higher T i led to increased ion–electron heating rates with magnitudes comparable to those computed for alpha electron heating. Rates of other heating/loss processes also had comparable magnitudes. Simulations of T e assuming the observed scaling of T i are qualitatively consistent with the measured profiles, without invoking alpha heating

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Confinement and heating of a deuterium-tritium plasma

Cited by 94 publications

References 8 publications

A phenomenological explanation for the anomalous ion heating observed in the JET alpha-heating experiment of 1997

A phenomenological explanation for the anomalous ion heating observed in the JET alpha-heating experiment of 1997

Excitation of Alfvén eigenmodes by fusion-born alpha-particles in D-³He plasmas on JET

Alpha heating and isotopic mass effects in JET plasmas with sawteeth

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Confinement and heating of a deuterium-tritium plasma

Cited by 94 publications

References 8 publications

A phenomenological explanation for the anomalous ion heating observed in the JET alpha-heating experiment of 1997

A phenomenological explanation for the anomalous ion heating observed in the JET alpha-heating experiment of 1997

Excitation of Alfvén eigenmodes by fusion-born alpha-particles in D-3He plasmas on JET

Alpha heating and isotopic mass effects in JET plasmas with sawteeth

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Product

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Excitation of Alfvén eigenmodes by fusion-born alpha-particles in D-³He plasmas on JET