An overview of results from the TCV tokamak

Goodman, T. P.; Ahmed, S.M.; Alberti, S.; Andrèbe, Y.; Angioni, C.; Appert, K.; Arnoux, G.; Behn, R.; Blanchard, P.; Bosshard, P.; Camenen, Y.; Chavan, R.; Coda, S.; Condrea, I.; Degeling, A. W.; Duval, B.P.; Étienne, P.; Fasel, D.; Fasoli, A.; Favez, J.-Y.; Furno, I.; Henderson, M.; Hofmann, F.; Hogge, J.‐P.; Horáček, J.; Isoz, P. F.; Joye, B.; Karpushov, A.; Klimanov, I.; Lavanchy, P.; Lister, J.B.; Llobet, X.; Magnin, J.-C.; Manini, A.; Marlétaz, B.; Marmillod, P.; Martin, Yves; Martynov, An.; Mayor, J. M.; Mlynář, J.; Moret, J.M.; Nelson‐Melby, E.; Nikkola, P.; Paris, P.; Pérez, A.; Peysson, Y.; Pitts, R.A.; Pochelon, A.; Porte, L.; Raju, D.; Reimerdes, H.; Sauter, O.; Scarabosio, A.; Scavino, Edgar; Seo, S. h.; Siravo, U.; Sushkov, A. V.; Tonetti, G.; Tran, M.Q.; Weisen, H.; Wischmeier, M.; Zabolotsky, A.; Zhuang, G.

doi:10.1088/0029-5515/43/12/008

Cited by 29 publications

(20 citation statements)

References 40 publications

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“…ions with energies much larger than the background plasma. These can be generated by coherent or turbulent acceleration mechanisms or by shocks (Reames 1999;Perri and Zimbardo 2012), or directly by external sources (neutral beams and/or EC resonance heating (ECRH and current drive (CD), (Goodman et al 2003;Henderson et al 2003)) or nuclear reactions, as in the case of magnetic fusion devices. Common to all of these systems is the question of how plasma turbulence influences suprathermal particles and, in turn, how suprathermal particles influence turbulence.…”

Section: Suprathermal Ion Physicsmentioning

confidence: 99%

Plasma turbulence, suprathermal ion dynamics and code validation on the basic plasma physics device TORPEX

et al. 2015

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The TORPEX basic plasma physics device at the Center for Plasma Physics Research (CRPP) in Lausanne, Switzerland is described. In TORPEX, simple magnetized toroidal configurations, a paradigm for the tokamak scrape-off layer (SOL), as well as more complex magnetic geometries of direct relevance for fusion are produced. Plasmas of different gases are created and sustained by microwaves in the electron-cyclotron (EC) frequency range. Full diagnostic access allows for a complete characterization of plasma fluctuations and wave fields throughout the entire plasma volume, opening new avenues to validate numerical codes. We detail recent advances in the understanding of basic aspects of plasma turbulence, including its development from linearly unstable electrostatic modes, the formation of filamentary structures, or blobs, and its influence on the transport of energy, plasma bulk and suprathermal ions. We present a methodology for the validation of plasma turbulence codes, which focuses on quantitative assessment of the agreement between numerical simulations and TORPEX experimental data.

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Section: Suprathermal Ion Physicsmentioning

confidence: 99%

Plasma turbulence, suprathermal ion dynamics and code validation on the basic plasma physics device TORPEX

et al. 2015

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“…The dependence of the suprathermal population on the toroidal injection angle is clearly demonstrated by figure 1, which shows the effect of sweeping during a plasma discharge on two out of three launchers: while the bulk temperature and the lower energy HXR signal remain constant, the high-energy HXR emission and the ECE radiative temperature increase rapidly with [19]. This example also illustrates the high degree of external control of multiple deposition locations and toroidal injection angles available on TCV, which has proven instrumental in the application of ECCD to current and pressure profile tailoring [5][6][7][20][21][22].…”

Section: Eccd and Suprathermal Electronsmentioning

confidence: 99%

“…The TCV tokamak (R = 0.88 cm, a = 0.25 cm, I p 1 MA, B φ 1.54 T) is equipped with a 4.5 MW EC heating system, powered by six second harmonic (X2, 82.7 GHz) and three third harmonic (X3, 118 GHz) 0.5 MW gyrotrons. An extremely flexible EC beam delivery system, allowing real-time poloidal and toroidal steering, matches the equally flexible plasma position and shape control system of TCV [5].…”

Section: Introductionmentioning

confidence: 99%

Electron cyclotron current drive and suprathermal electron dynamics in the TCV tokamak

Coda

Alberti

Blanchard³

et al. 2003

Nucl. Fusion

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Electron cyclotron current drive (ECCD) is an important prospective tool for tailoring the current profile in nextstep devices. To fill the remaining gaps between ECCD theory and experiment, especially in the efficiency and localization of current drive, a better understanding of the physics of suprathermal electrons appears necessary. In TCV, the fast electron population is diagnosed by a multichordal, spectrometric hard x-ray camera and by a highfield side electron cyclotron emission radiometer. The main modelling tool is the quasilinear Fokker-Planck code CQL3D, which is equipped with a radial particle transport model. Systematic studies of fast electron dynamics have been performed in TCV with modulated or pulsed electron cyclotron power, followed by coherent averaging, in order to identify the roles of collisional relaxation and radial transport in the dynamics of the suprathermal population. A consistent picture is emerging from experiment and modelling, pointing to the crucial role of the radial transport of suprathermal electrons in the physics of ECCD.

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“…The ECRH delivery system provides unique flexibility: the second-harmonic system at 82.7 GHz consists of six 0.45 MW beams delivered by six independent launchers, which can be steered in real time to provide either pure heating or cocurrent and countercurrent drive ͑ECCD͒ simultaneously at different locations within the plasma. 16 An equally flexible control system, based on 16 independently powered shaping coils, permits the control of extremely varied plasma shapes and positions within the vacuum chamber ͑elongation 0.9 ഛ ഛ 2.8, triangularity −0.6ഛ ␦ ഛ + 0.9͒. The main plasma parameters are as follows: major radius R = 0.88 cm, minor radius a = 0.25 cm, plasma current I p ഛ 1 MA, toroidal magnetic field B ഛ 1.54 T, total ECRH power ͑second and third harmonic, 82.7 and 118 GHz, respectively͒ P EC = 4.5 MW.…”

Section: Introductionmentioning

confidence: 99%

High-bootstrap, noninductively sustained electron internal transport barriers in the Tokamak à Configuration Variable

Coda¹,

Goodman²,

Henderson³

et al. 2005

Physics of Plasmas

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Important ingredients of the advanced-tokamak route to fusion have been explored in depth in the Tokamak à Configuration Variable ͓F. Hofmann, J. B. Lister, M. Anton et al., Plasma Phys. Controlled Fusion 36, B277 ͑1994͔͒ over the past two years. Using a uniquely powerful and flexible electron-cyclotron resonance heating ͑ECRH͒ system as the primary actuator, fully noninductive, steady-state electron internal transport barrier discharges have been generated with an electron-energy confinement time up to five times longer than in L mode, poloidal ␤ up to 2.4, and bootstrap fraction up to 75%. Interpretative transport modeling confirms that the safety factor profile is nonmonotonic in these discharges. The formation of the barrier is a discrete event resulting in rapid and localized confinement improvement consistent with the time and location of magnetic-shear reversal. In steady state, however, the confinement quality appears to depend on the current gradient in a broader negative-shear region enclosed by the barrier, improving with increasing shear: in particular, the width and depth of the barrier can be controlled and finely tuned, along a magnetohydrodynamic-stable path, by manipulating the current profile with ECRH ͑six independently steerable 0.45 MW launchers͒. The crucial role of the current profile has been clearly demonstrated by applying small Ohmic current perturbations which dramatically alter the properties of the barrier, enhancing or reducing the confinement with negative and positive current, respectively, with negligible Ohmic heating. These results are in agreement with theoretical estimates: first-principle-based numerical simulations of microinstability dynamics and turbulence-driven transport predict a substantial suppression of turbulence and anomalous energy diffusivity near the location of the minimum in the safety factor.

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An overview of results from the TCV tokamak

Cited by 29 publications

References 40 publications

Plasma turbulence, suprathermal ion dynamics and code validation on the basic plasma physics device TORPEX

Plasma turbulence, suprathermal ion dynamics and code validation on the basic plasma physics device TORPEX

Electron cyclotron current drive and suprathermal electron dynamics in the TCV tokamak

High-bootstrap, noninductively sustained electron internal transport barriers in the Tokamak à Configuration Variable

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