Progress in diagnostics of the COMPASS tokamak

Weinzettl, V.; Adámek, Jiřı́; Berta, M.; Bílková, P.; Bogar, O.; Böhm, P.; Cavalier, J.; Dejarnac, R.; Dimitrova, M.; Ficker, O.; Fridrich, David; Grover, O.; Hacek, P.; Havlíček, Jan; Havránek, A.; Horáček, J.; Hron, M.; Imríšek, M.; Komm, M.; Kovařík, K.; Krbec, J.; Markovič, T.; Matveeva, E.; Mitošínková, K.; Mlynář, J.; Naydenkova, D.; Pánek, R.; Paprok, R.; Peterka, M.; Podolník, A.; Seidl, J.; Šos, M.; Ştöckel, J.; Tomeš, M.; Varavin, M.; Varju, J.; Vlainic, M.; Vondráček, P.; Zaja̧c, J.; Žáček, F.; Staňo, Michal; Anda, G.; Dunai, D.; Krizsanóczi, T.; Refy, D.; Zoletnik, S.; Silva, A.; Gomes, R.; Pereira, Tiago; Popov, Tsv.; Sarychev, D. V.; Ermak, G. P.; Zebrowski, J.; Jakubowski, M.; Rabiński, M.; Malinowski, K.; Nanobashvili, S.; Spolaore, M.; Vianello, N.; Gauthier, E.; Gunn, J.; Devitre, A.

doi:10.1088/1748-0221/12/12/c12015

Cited by 10 publications

(7 citation statements)

References 49 publications

(57 reference statements)

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“…However, for such an analysis additional discharges are necessary in order to obtain a sufficiently large dataset of Thomson scattering pressure profiles. The recent installation of 2 additional lasers [35] will also favor the collection of such a dataset.…”

Section: Discussionmentioning

confidence: 99%

Limit cycle oscillations measurements with Langmuir and ball-pen probes on COMPASS

Grover¹,

Seidl²,

Réfy³

et al. 2018

Nucl. Fusion

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This contribution presents the experimentally observed edge plasma evolution during limit cycle oscillations (LCO) measured with a new Langmuir and ball-pen multi-pin probe head at the COMPASS tokamak. The observed LCO regime modulates the intensity of density fluctuations , radial electric field Er and intensity of emission with a frequency 3–5 kHz. The density fluctuations grow after Er decreases in strength which appears to be strongly correlated with the evolution of the pressure gradient . The magnetic signature of the LCO shows a left–right asymmetry with propagation from the low to high field side. High-frequency (above 100 kHz) precursor-like oscillations are observed as well.

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Section: Discussionmentioning

confidence: 99%

Limit cycle oscillations measurements with Langmuir and ball-pen probes on COMPASS

Grover¹,

Seidl²,

Réfy³

et al. 2018

Nucl. Fusion

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“…The tokamak operation in advanced discharge regimes such as the ELMy H-mode [1] or detachment [14] are routinely achieved, showing the high relevance of the research towards ITER. A sophisticated set of plasma diagnostics allows detailed studies, focused in particular on edge plasma physics [2]. A picture of COMPASS in the torus hall (left) and a comparison of its size with other fusion facilities and with the ITER-like plasma cross-section (right) is shown in figure 1.…”

Section: The Compass Tokamakmentioning

confidence: 99%

More than 30 years of experience in fusion education at the Institute of Plasma Physics of the Czech Academy of Sciences

Ştöckel¹,

Cavalier²,

Mlynář³

et al. 2021

Eur. J. Phys.

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The complexity of making magnetic confinement fusion a suitable source of energy for mankind imposes long lasting investigations. To accompany these efforts, new generations of physicists have to be trained over the years to ensure continuity of the research. These scientists must have very versatile profiles as fusion inquiries are multiphysics (magnetohydrodynamic, plasma-wall interactions, cutting edge technologies...) and require skills in both experimental and theoretical physics. The Institute of Plasma Physics IPP Prague of the Czech Academy of Sciences (IPP Prague) has contributed to the education and training of a non-negligible number of students in this area, one reason being the good accessibility of its fusion facility, the other being its strong connection with universities. This article shows the views and achievements of IPP Prague on education. In particular, we insist on the fact that to keep students in the field they have to be acquainted with practical plasma physics as early as possible (on the bachelor level if possible). We also show that a strong integration of PhD candidates within the scientific staff is an important factor for their training and serves them to be autonomous. Last, we present two experimental 2 weeks training courses, called SUMTRAIC and EMTRAIC, that are annually organized by IPP Prague and that have acquainted more than 300 participants to the practical physics of tokamaks.

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“…Photoneutrons may be also detected by multiple neutron detectors, but the contrib ution of photoneutrons is mixed with HXRs in the case of large fluxes that affect even the shielded detectors. A wide-angle view and detailed observations of the RE beam in the visible range are provided by the fast cameras Photron MINI UX-100 [21] and Photron SA-X2, respectively. Spectral data in the visible, near-IR and near-UV regions are acquired using various minispectrometers.…”

Section: Diagnostics and Gas Injection Valvesmentioning

confidence: 99%

Runaway electron beam stability and decay in COMPASS

et al. 2019

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Runaway electrons (REs) as one of the yet unsolved threats for ITER and future tokamaks are a topic of intensive research at most of the European tokamaks. The experiments performed on COMPASS are complementary to the experiments at JET and MST (Medium-Size Tokamaks), building on the flexibility of the diagnostics setup and low safety constraints at this smaller device. During the past couple of years two different scenarios with the RE beam generation triggered by gas injection have been developed and investigated. The first one is based on Ar or Ne massive gas injection (MGI) into the current ramp-up phase leading to a disruption accompanied by runaway plateau generation [1], while the second uses smaller amounts of gas in order to get runaway current dominated plasmas [2]. The successful generation of the beam in the first scenario depends on various parameters, including the toroidal magnetic field. The generated beam is often radially unstable, and the stability seems to be a function of various parameters, including the value of current lost during the CQ. The second scenario is much more quiescent, with no observable fast current quench and it is highly reproducible. This allows to reasonably diagnose the beam phase and also to apply secondary injections or resonant magnetic perturbations (RMP) to assist the decay of the beam. In this regard, interesting results have been achieved using secondary deuterium injection into a runaway electron beam triggered by Ar or Ne. The current of the RE beam can be controlled at a fixed value, however only using relatively high loop voltage. The radial position is not fully controlled and the request for the stabilising field is changing independently on plasma current which implies that the RE energy plays a key role in correct approach to beam position control. The experiments with elongated beams were also carried out. Last but not least it seems that Ar and Ne behave differently in terms of radiated power and HXR intensity during the beam decay. 1.

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Progress in diagnostics of the COMPASS tokamak

Cited by 10 publications

References 49 publications

Limit cycle oscillations measurements with Langmuir and ball-pen probes on COMPASS

Limit cycle oscillations measurements with Langmuir and ball-pen probes on COMPASS

More than 30 years of experience in fusion education at the Institute of Plasma Physics of the Czech Academy of Sciences

Runaway electron beam stability and decay in COMPASS

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