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919 results on '"Hoppe, M"'

1. Cross-Calibration and First Vertical ECE Measurement of Electron Energy Distribution in the TCV Tokamak

Author

Biwole, A. Tema, Porte, L., Fasoli, A., Figini, L., Decker, J., Hoppe, M., Cazabonne, J., Votta, L., Simonetto, A., Coda, S., and Team, TCV

Subjects
Physics - Plasma Physics
Abstract

This paper describes the first Vertical Electron Cyclotron Emission (V-ECE) measurement of non-thermal electron distributions in the \textit{Tokamak \`a Configuration Variable}, TCV. These measurements were conducted in runaway electron scenarios and in the presence of Electron Cyclotron Current Drive. Measured intensities of linearly polarised X- and O-mode radiation from fast electrons allow the analysis of the energy distribution. The measurements were made possible through the creation of an operational regime for the diagnostic that is free of thermal background radiation, in relaxed electron density operations. This operational regime notably enables the cross-calibration of the diagnostic system, relying on thermal plasma measurements and modeling with the ray-tracing code SPECE., Comment: Submitted to: Plasma Phys. Control. Fusion

Published
2024
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2. First numerical analysis of runaway electron generation in tungsten-rich plasmas towards ITER

Author

Walkowiak, J., Hoppe, M., Ekmark, I., Jardin, A., Bielecki, J., Król, K., Savoye-Peysson, Y., Mazon, D., Dworak, D., and Scholz, M.

Subjects
Physics - Plasma Physics
Abstract

The disruption and runaway electron analysis model code was extended to include tungsten impurities in disruption simulations with the aim of studying the runaway electron (RE) generation. This study investigates RE current sensitivity on the following plasma parameters and modelling choices: tungsten concentration, magnetic perturbation strength, electron modelling, thermal quench time and tokamak geometry: ITER-like or ASDEX-like. Our investigation shows that a tungsten concentration below 10-3 does not cause significant RE generation on its own. However, at higher concentrations it is possible to reach a very high RE current. Out of the two tested models of electrons in plasma: fluid and isotropic (kinetic), results from the fluid model are more conservative, which is useful when it comes to safety analysis. However, these results are overly pessimistic when compared to the isotropic model, which is based on a more reliable approach. Our results also show that the hot-tail RE generation mechanism is dominant as a primary source of RE in tungsten induced disruptions, usually providing orders of magnitude higher RE seed than Dreicer generation. We discuss best practices for simulations with tungsten-rich plasma, present the dependence of the safety limits on modelling choices and highlight the biggest shortcoming of the current simulation techniques. The obtained results pave the way for a wider analysis of tungsten impact on the disruption dynamics, including the mitigation techniques for ITER in the case of strong contamination of the plasma with tungsten.

Published
2024
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3. Expulsion of runaway electrons using ECRH in the TCV tokamak

Author

Decker, J., Hoppe, M., Sheikh, U., Duval, B. P., Papp, G., Simons, L., Wijkamp, T., Cazabonne, J., Coda, S., Devlaminck, E., Ficker, O., Hellinga, R., Kumar, U., Savoye-Peysson, Y., Porte, L., Reux, C., Sommariva, C., Biwolé, A. Tema, Vincent, B., Votta, L., Team, the TCV, and Team, the EUROfusion Tokamak Exploitation

Subjects
Physics - Plasma Physics
Abstract

Runaway electrons (REs) are a concern for tokamak fusion reactors from discharge startup to termination. A sudden localized loss of a multi-megaampere RE beam can inflict severe damage to the first wall. Should a disruption occur, the existence of a RE seed may play a significant role in the formation of a RE beam and the magnitude of its current. The application of central electron cyclotron resonance heating (ECRH) in the Tokamak \`a Configuration Variable (TCV) reduces an existing RE seed population by up to three orders of magnitude within only a few hundred milliseconds. Applying ECRH before a disruption can also prevent the formation of a post-disruption RE beam in TCV where it would otherwise be expected. The RE expulsion rate and consequent RE current reduction are found to increase with applied ECRH power. Whereas central ECRH is effective in expelling REs, off-axis ECRH has a comparatively limited effect. A simple 0-D model for the evolution of the RE population is presented that explains the effective ECRH-induced RE expulsion results from the combined effects of increased electron temperature and enhanced RE transport.

Published
2024

4. Inelastic collisions facilitating runaway electron generation in weakly-ionized plasmas

Author

Lee, Y., Aleynikov, P., de Vries, P. C., Kim, H. -T., Lee, J., Hoppe, M., Park, J. -K., Choi, G. J., Gwak, J., and Na, Y. -S.

Subjects
Physics - Plasma Physics
Abstract

Dreicer generation is one of the main mechanisms of runaway electrons generation, in particular during tokamak startup. In fully ionized plasma it is described as a diffusive flow from the Maxwellian core into high energies under the effect of the electric field. In this work we demonstrate a critical role of the non-differential nature of inelastic collisions in weakly ionized plasma during tokamak startup, where some electrons experience virtually no collisions during acceleration to the critical energy. We show that using the Fokker-Planck collisional operator can underestimate the Dreicer generation rate by several orders of magnitude.

Published
2023

5. On the minimum transport required to passively suppress runaway electrons in SPARC disruptions

Author

Tinguely, R. A., Pusztai, I., Izzo, V. A., S'"arkimäki, K., Fülöp, T., Garnier, D. T., Granetz, R. S., Hoppe, M., Paz-Soldan, C., Sundström, A., and Sweeney, R.

Subjects
Physics - Plasma Physics
Abstract

In [V.A. Izzo et al 2022 Nucl. Fusion 62 096029], state-of-the-art modeling of thermal and current quench (CQ) MHD coupled with a self-consistent evolution of runaway electron (RE) generation and transport showed that a non-axisymmetric (n = 1) in-vessel coil could passively prevent RE beam formation during disruptions in SPARC, a compact high-field tokamak projected to achieve a fusion gain Q > 2 in DT plasmas. However, such suppression requires finite transport of REs within magnetic islands and re-healed flux surfaces; conservatively assuming zero transport in these regions leads to an upper bound of RE current ~1 MA compared to ~8.7 MA of pre-disruption plasma current. Further investigation finds that core-localized electrons, within r/a < 0.3 and with kinetic energies 0.2-15 MeV, contribute most to the RE plateau formation. Yet only a relatively small amount of transport, i.e. a diffusion coefficient ~18 $\mathrm{m^2/s}$, is needed in the core to fully mitigate these REs. Properly accounting for (i) the CQ electric field's effect on RE transport in islands and (ii) the contribution of significant RE currents to disruption MHD may help achieve this.

Published
2023
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6. Runaway dynamics in reactor-scale spherical tokamak disruptions

Author

Berger, E., Pusztai, I., Newton, S. L., Hoppe, M., Vallhagen, O., Fil, A., and Fülöp, T.

Subjects
Physics - Plasma Physics
Abstract

Understanding generation and mitigation of runaway electrons in disruptions is important for the safe operation of future tokamaks. In this paper we investigate runaway dynamics in reactor-scale spherical tokamaks. We study both the severity of runaway generation during unmitigated disruptions, as well as the effect that typical mitigation schemes based on massive material injection have on runaway production. The study is conducted using the numerical framework DREAM (Disruption Runaway Electron Analysis Model). We find that, in many cases, mitigation strategies are necessary to prevent the runaway current from reaching multi-megaampere levels. Our results indicate that with a suitably chosen deuterium-neon mixture for mitigation, it is possible to achieve a tolerable runaway current and ohmic current evolution. With such parameters, however, the majority of the thermal energy loss happens through radial transport rather than radiation, which poses a risk of unacceptable localised heat loads., Comment: 19 pages, 7 figures

Published
2022
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7. Runaway electron generation during tokamak start-up

Author

Hoppe, M., Ekmark, I., Berger, E., and Fülöp, T.

Subjects
Physics - Plasma Physics
Abstract

Tokamak start-up is characterized by low electron densities and strong electric fields, in order to quickly raise the plasma current and temperature, allowing the plasma to fully ionize and magnetic flux surfaces to form. Such conditions are ideal for the formation of superthermal electrons, which may reduce the efficiency of ohmic heating and prevent the formation of a healthy thermal fusion plasma. This is of particular concern in ITER where engineering limitations put restrictions on the allowable electric fields and limit the prefill densities during start-up. In this study, we present a new 0D burn-through simulation tool called STREAM (STart-up Runaway Electron Analysis Model), which self-consistently evolves the plasma density, temperature and electric field, while accounting for the generation and loss of relativistic runaway electrons. After verifying the burn-through model, we investigate conditions under which runaway electrons can form during tokamak start-up as well as their effects on the plasma initiation. We find that Dreicer generation plays a crucial role in determining whether a discharge becomes runaway-dominated or not, and that a large number of runaway electrons could limit the ohmic heating of the plasma, thus preventing successful burn-through or further ramp-up of the plasma current. The runaway generation can be suppressed by raising the density via gas fuelling, but only if done sufficiently early. Otherwise a large runaway seed may have already been built up, which can avalanche even at relatively low electric fields and high densities., Comment: 23 pages, 8 figures

Published
2022
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8. Effect of Two-Stage Shattered Pellet Injection on Tokamak Disruptions

Author

Vallhagen, O., Pusztai, I., Hoppe, M., Newton, S. L., and Fülöp, T.

Subjects
Physics - Plasma Physics
Abstract

An effective disruption mitigation system in a tokamak reactor should limit the exposure of the wall to localized heat losses and to the impact of high current runaway electron beams, and avoid excessive forces on the structure. We evaluate with respect to these aspects a two-stage deuterium-neon shattered pellet injection in an ITER-like plasma, using simulations with the DREAM framework [M. Hoppe et al (2021) Comp. Phys. Commun. 268, 108098]. To minimize the obtained runaway currents an optimal range of injected deuterium quantities is found. This range is sensitive to the opacity of the plasma to Lyman radiation, which affects the ionization degree of deuterium, and thus avalanche runaway generation. The two-stage injection scheme, where dilution cooling is produced by deuterium before a radiative thermal quench caused by neon, reduces both the hot-tail seed and the localized transported heat load on the wall. However, during nuclear operation, additional runaway seed sources from the activated wall and tritium make it difficult to reach tolerably low runaway currents., Comment: 17 pages, 7 figures, to be submitted to Nuclear Fusion

Published
2022
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9. Modeling the complete prevention of disruption-generated runaway electron beam formation with a passive 3D coil in SPARC

Author

Tinguely, RA, Izzo, VA, Garnier, DT, Sundström, A, Särkimäki, K, Embréus, O, Fülöp, T, Granetz, RS, Hoppe, M, Pusztai, I, and Sweeney, R

Subjects
Physics - Plasma Physics
Abstract

The potential formation of multi-mega-ampere beams of relativistic "runaway" electrons (REs) during sudden terminations of tokamak plasmas poses a significant challenge to the tokamak's development as a fusion energy source. Here, we use state-of-the-art modeling of disruption magnetohydrodynamics coupled with a self-consistent evolution of RE generation and transport to show that a non-axisymmetric in-vessel coil will passively prevent RE beam formation during disruptions in the SPARC tokamak, a compact, high-field, high-current device capable of achieving a fusion gain Q > 2 in deuterium-tritium plasmas.

Published
2021
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10. DREAM: a fluid-kinetic framework for tokamak disruption runaway electron simulations

Author

Hoppe, M., Embreus, O., and Fülöp, T.

Subjects
Physics - Plasma Physics
Abstract

Avoidance of the harmful effects of runaway electrons (REs) in plasma-terminating disruptions is pivotal in the design of safety systems for magnetic fusion devices. Here, we describe a computationally efficient numerical tool, that allows for self-consistent simulations of plasma cooling and associated RE dynamics during disruptions. It solves flux-surface averaged transport equations for the plasma density, temperature and poloidal flux, using a bounce-averaged kinetic equation to self-consistently provide the electron current, heat, density and RE evolution, as well as the electron distribution function. As an example, we consider disruption scenarios with material injection and compare the electron dynamics resolved with different levels of complexity, from fully kinetic to fluid modes., Comment: 33 pages, 11 figures

Published
2021
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11. Validity of models for Dreicer generation of runaway electrons in dynamic scenarios

Author

Olasz, S., Embreus, O., Hoppe, M., Aradi, M., Por, D., Jonsson, T., Yadikin, D., Pokol, G. I., and Team, EU-IM

Subjects
Physics - Plasma Physics
Abstract

Runaway electron modelling efforts are motivated by the risk these energetic particles pose to large fusion devices. The sophisticated kinetic models can capture most features of the runaway electron generation but have high computational costs which can be avoided by using computationally cheaper reduced kinetic codes. In this paper, we compare the reduced kinetic and kinetic models to determine when the former solvers, based on analytical calculations assuming quasi-stationarity, can be used. The Dreicer generation rate is calculated by two different solvers in parallel in a workflow developed in the European Integrated Modelling framework, and this is complemented by calculations of a third code that is not yet integrated into the framework. Runaway Fluid, a reduced kinetic code, NORSE, a kinetic code using non-linear collision operator, and DREAM, a linearized Fokker-Planck solver, are used to investigate the effect of a dynamic change in the electric field for different plasma scenarios spanning across the whole tokamak-relevant range. We find that on time scales shorter than or comparable to the electron collision time at the critical velocity for runaway electron generation kinetic effects not captured by reduced kinetic models play an important role. This characteristic time scale is easy to calculate and can reliably be used to determine whether there is a need for kinetic modelling, or cheaper reduced kinetic codes are expected to deliver sufficiently accurate results. This criterion can be automated, and thus it can be of great benefit for the comprehensive self-consistent modelling frameworks that are attempting to simulate complex events such as tokamak start-up or disruptions.

Published
2021
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12. Tomographic reconstruction of the runaway distribution function in TCV using multispectral synchrotron images

Author

Wijkamp, T. A., Perek, A., Decker, J., Duval, B., Hoppe, M., Papp, G., Sheikh, U. A., Classen, I. G. J., Jaspers, R. J. E., team, the TCV, and team, the EUROfusion MST1

Subjects
Physics - Plasma Physics
Abstract

Synchrotron radiation observed in a quiescent TCV runaway discharge is studied using filtered camera images targeting three distinct wavelength intervals. Through the tomographic SART procedure the high momentum, high pitch angle part of the spatial and momentum distribution of these relativistic particles is reconstructed. Experimental estimates of the distribution are important for verification and refinement of formation-, decay- and transport-models underlying runaway avoidance and mitigation strategy design. Using a test distribution it is demonstrated that the inversion procedure provides estimates accurate to within a few tens of percent in the region of phase-space contributing most to the synchrotron image. We find that combining images filtered around different parts of the emission spectrum widens the probed part of momentum-space and reduces reconstruction errors. Next, the SART algorithm is used to obtain information on the spatiotemporal runaway momentum distribution in a selected TCV discharge. The momentum distribution is found to relax towards an avalanche-like exponentially decaying profile. Anomalously high pitch angles and a radial profile increasing towards the edge are found for the most strongly emitting particles in the distribution. Pitch angle scattering by toroidal magnetic field ripple is consistent with this picture. An alternative explanation is the presence of high frequency instabilities in combination with the formation of a runaway shell at the edge of the plasma., Comment: 18 pages, 13 figures, submitted to Nuclear Fusion

Published
2020
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13. Spatiotemporal analysis of the runaway distribution function from synchrotron images in an ASDEX Upgrade disruption

Author

Hoppe, M., Hesslow, L., Embreus, O., Unnerfelt, L., Papp, G., Pusztai, I., Fülöp, T., Lexell, O., Lunt, T., Macusova, E., McCarthy, P. J., Pautasso, G., Pokol, G. I., Por, G., Svensson, P., team, the ASDEX Upgrade, and team, the EUROfusion MST1

Subjects
Physics - Plasma Physics
Abstract

Synchrotron radiation images from runaway electrons (REs) in an ASDEX Upgrade discharge disrupted by argon injection are analyzed using the synchrotron diagnostic tool SOFT and coupled fluid-kinetic simulations. We show that the evolution of the runaway distribution is well described by an initial hot-tail seed population, which is accelerated to energies between 25-50 MeV during the current quench, together with an avalanche runaway tail which has an exponentially decreasing energy spectrum. We find that, although the avalanche component carries the vast majority of the current, it is the high-energy seed remnant that dominates synchrotron emission. With insights from the fluid-kinetic simulations, an analytic model for the evolution of the runaway seed component is developed and used to reconstruct the radial density profile of the RE beam. The analysis shows that the observed change of the synchrotron pattern from circular to crescent shape is caused by a rapid redistribution of the radial profile of the runaway density., Comment: 25 pages, 12 figures

Published
2020
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14. Runaway electron synchrotron radiation in a vertically translated plasma

Author

Hoppe, M., Papp, G., Wikjamp, T., Perek, A., Decker, J., Duval, B., Embreus, O., Fülöp, T., and Sheikh, U. A.

Subjects
Physics - Plasma Physics
Abstract

Synchrotron radiation observed from runaway electrons (REs) in tokamaks depends upon the position and size of the RE beam, the RE energy and pitch distributions, as well as the location of the observer. We show that experimental synchrotron images of a vertically moving runaway electron beam sweeping past the detector in the TCV tokamak agree well with predictions from the synthetic synchrotron diagnostic Soft. This experimental validation lends confidence to the theory underlying the synthetic diagnostics which are used for benchmarking theoretical models of and probing runaway dynamics. We present a comparison of synchrotron measurements in TCV with predictions of kinetic theory for runaway dynamics in uniform magnetic fields. We find that to explain the detected synchrotron emission, significant non-collisional pitch angle scattering as well as radial transport of REs would be needed. Such effects could be caused by the presence of magnetic perturbations, which should be further investigated in future TCV experiments., Comment: 7 pages, 4 figures. Accepted for publication in Nuclear Fusion

Published
2020
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16. Evaluation of the Dreicer runaway generation rate in the presence of high-Z impurities using a neural network

Author

Hesslow, L, Unnerfelt, L, Vallhagen, O, Embreus, O, Hoppe, M, Papp, G, and Fülöp, T

Subjects
Physics - Plasma Physics
Abstract

Integrated modelling of electron runaway requires computationally expensive kinetic models that are self-consistently coupled to the evolution of the background plasma parameters. The computational expense can be reduced by using parameterized runaway generation rates rather than solving the full kinetic problem. However, currently available generation rates neglect several important effects; in particular, they are not valid in the presence of partially ionized impurities. In this work, we construct a multilayer neural network for the Dreicer runaway generation rate which is trained on data obtained from kinetic simulations performed for a wide range of plasma parameters and impurities. The neural network accurately reproduces the Dreicer runaway generation rate obtained by the kinetic solver. By implementing it in a fluid runaway electron modelling tool, we show that the improved generation rates lead to significant differences in the self-consistent runaway dynamics as compared to the results using the previously available formulas for the runaway generation rate., Comment: 16 pages, 5 figures

Published
2019
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17. Experimental and synthetic measurements of polarized synchrotron emission from runaway electrons in Alcator C-Mod

Author

Tinguely, R. A., Hoppe, M., Granetz, R. S., Mumgaard, R. T., and Scott, S.

Subjects
Physics - Plasma Physics
Abstract

This paper presents the first experimental analysis of polarized synchrotron emission from relativistic runaway electrons (REs) in a tokamak plasma. Importantly, we show that the polarization information of synchrotron radiation can be used to diagnose spatially-localized RE pitch angle distributions. Synchrotron-producing REs were generated during low density, Ohmic, diverted plasma discharges in the Alcator C-Mod tokamak. The ten-channel Motional Stark Effect diagnostic was used to measure spatial profiles of the polarization angle $\theta_{\mathrm{pol}}$ and the fraction $\mathrm{f}_{\mathrm{pol}}$ of detected light that was linearly-polarized. Spatial transitions in $\theta_{\mathrm{pol}}$ of 90$\deg$---from horizontal to vertical polarization and vice versa---are observed in experimental data and are well-explained by the gyro-motion of REs and high directionality of synchrotron radiation. Polarized synchrotron emission is modeled with the synthetic diagnostic SOFT; its output Green's (or detector response) functions reveal a critical RE pitch angle at which $\theta_{\mathrm{pol}}$ flips by 90$\deg$ and $\mathrm{f}_{\mathrm{pol}}$ is minimal. Using SOFT, we determine the dominant RE pitch angle which reproduces measured $\theta_{\mathrm{pol}}$ and $\mathrm{f}_{\mathrm{pol}}$ values. The spatiotemporal evolutions of $\theta_{\mathrm{pol}}$ and $\mathrm{f}_{\mathrm{pol}}$ are explored in detail for one C-Mod discharge. For channels viewing REs near the magnetic axis and flux surfaces $q$ = 1 and 4/3, disagreements between synthetic and experimental signals suggest that the sawtooth instability may be influencing RE dynamics. Furthermore, other sources of pitch angle scattering, not considered in this analysis, could help explain discrepancies between simulation and experiment.

Published
2019
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18. Benign termination of runaway electron beams on ASDEX Upgrade and TCV

Author

Sheikh, U, Decker, J, Hoppe, M, Pedrini, M, Sieglin, B, Simons, L, Cazabonne, J, Caloud, J, Cerovsky, J, Coda, S, Colandrea, C, Dal Molin, A, Duval, B, Ficker, O, Griener, M, Papp, G, Pautasso, G, Paz-Soldan, C, Reux, C, Tomesova, E, Wijkamp, T, Sheikh U., Decker J., Hoppe M., Pedrini M., Sieglin B., Simons L., Cazabonne J., Caloud J., Cerovsky J., Coda S., Colandrea C., Dal Molin A., Duval B., Ficker O., Griener M., Papp G., Pautasso G., Paz-Soldan C., Reux C., Tomesova E., Wijkamp T., Sheikh, U, Decker, J, Hoppe, M, Pedrini, M, Sieglin, B, Simons, L, Cazabonne, J, Caloud, J, Cerovsky, J, Coda, S, Colandrea, C, Dal Molin, A, Duval, B, Ficker, O, Griener, M, Papp, G, Pautasso, G, Paz-Soldan, C, Reux, C, Tomesova, E, Wijkamp, T, Sheikh U., Decker J., Hoppe M., Pedrini M., Sieglin B., Simons L., Cazabonne J., Caloud J., Cerovsky J., Coda S., Colandrea C., Dal Molin A., Duval B., Ficker O., Griener M., Papp G., Pautasso G., Paz-Soldan C., Reux C., Tomesova E., and Wijkamp T.

Abstract

This paper discusses the development of a benign termination scenario for runaway electron (RE) beams on ASDEX Upgrade and TCV. A systematic study revealed that a low electron density (n e) companion plasma was required to achieve a large MHD instability, which expelled the confined REs over a large wetted area and allowed for the conversion of magnetic energy to radiation. Control of the companion plasma ne was achieved via neutral pressure regulation and was agnostic to material injection method. The neutral pressure required for recombination was found to be dependent on impurity species, quantity and RE current. On TCV, n e increased at neutral pressures above 1 Pa, indicating that higher collisionality between the REs and neutrals may lead to an upper pressure limit. The conversion of magnetic energy to radiated energy was measured on both machines and a decrease in efficiency was observed at high neutral pressure on TCV. The benign termination technique was able to prevent any significant increase in maximum heat flux on AUG from 200 to 600 kA of RE current, highlighting the ability of this approach to handle fully formed RE beams.

Published
2024

19. Spatiotemporal evolution of runaway electrons from synchrotron images in Alcator C-Mod

Author

Tinguely, R. A., Granetz, R. S., Hoppe, M., and Embréus, O.

Subjects
Physics - Plasma Physics
Abstract

In the Alcator C-Mod tokamak, relativistic runaway electron (RE) generation can occur during the flattop current phase of low density, diverted plasma discharges. Due to the high toroidal magnetic field (B = 5.4 T), RE synchrotron radiation is measured by a wide-view camera in the visible wavelength range (~400-900 nm). In this paper, a statistical analysis of over one thousand camera images is performed to investigate the plasma conditions under which synchrotron emission is observed in C-Mod. In addition, the spatiotemporal evolution of REs during one particular discharge is explored in detail via a thorough analysis of the distortion-corrected synchrotron images. To accurately predict RE energies, the kinetic solver CODE [Landreman et al 2014 Comput. Phys. Commun. 185 847-855] is used to evolve the electron momentum-space distribution at six locations throughout the plasma: the magnetic axis and flux surfaces q = 1, 4/3, 3/2, 2, and 3. These results, along with the experimentally-measured magnetic topology and camera geometry, are input into the synthetic diagnostic SOFT [Hoppe et al 2018 Nucl. Fusion 58 026032] to simulate synchrotron emission and detection. Interesting spatial structure near the surface q = 2 is found to coincide with the onset of a locked mode and increased MHD activity. Furthermore, the RE density profile evolution is fit by comparing experimental to synthetic images, providing important insight into RE spatiotemporal dynamics.

Published
2018
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20. Generalized collision operator for fast electrons interacting with partially ionized impurities

Author

Hesslow, L, Embréus, O, Hoppe, M, DuBois, T C, Papp, G, Rahm, M, and Fülöp, T

Subjects
Physics - Plasma Physics
Abstract

Accurate modelling of the interaction between fast electrons and partially ionized atoms is important for evaluating tokamak disruption mitigation schemes based on material injection. This requires accounting for the effect of screening of the impurity nuclei by the cloud of bound electrons. In this paper, we detail the derivation of a generalized collision operator including the effect of partial screening. We calculate the effective ion length-scales, which are needed in the components of the collision operator, for a number of ion species commonly appearing in fusion experiments. We show that for high electric fields, the secondary runaway growth rate can be substantially larger than in a fully ionized plasma with the same effective charge, although the growth rate is significantly reduced at near-critical electric fields. Furthermore, by comparison with the Boltzmann collision operator, we show that the Fokker--Planck formalism is valid even for large impurity content., Comment: Peer-reviewed version

Published
2018
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21. Measurements of runaway electron synchrotron spectra at high magnetic fields in Alcator C-Mod

Author

Tinguely, R. A., Granetz, R. S., Hoppe, M., and Embreus, O.

Subjects
Physics - Plasma Physics
Abstract

In the Alcator C-Mod tokamak, runaway electron (RE) experiments have been performed during low density, flattop plasma discharges at three magnetic fields: 2.7, 5.4, and 7.8 T, the last being the highest field to-date at which REs have been generated and measured in a tokamak. Time-evolving synchrotron radiation spectra were measured in the visible wavelength range (~300-1000 nm) by two absolutely-calibrated spectrometers viewing co- and counter-plasma current directions. In this paper, a test particle model is implemented to predict momentum-space and density evolutions of REs on the magnetic axis and q = 1, 3/2, and 2 surfaces. Drift orbits and subsequent loss of confinement are also incorporated into the evolution. These spatiotemporal results are input into the new synthetic diagnostic SOFT [M. Hoppe, et al., Nucl. Fusion 58(2), 026032 (2018)] which reproduces experimentally-measured spectra. For these discharges, it is inferred that synchrotron radiation dominates collisional friction as a power loss mechanism and that RE energies decrease as magnetic field is increased. Additionally, the threshold electric field for RE generation, as determined by hard X-ray and photo-neutron measurements, is compared to current theoretical predictions.

Published
2018
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22. Interpretation of runaway electron synchrotron and bremsstrahlung images

Author

Hoppe, M., Embréus, O., Paz-Soldan, C., Moyer, R. A., and Fülöp, T.

Subjects
Physics - Plasma Physics
Abstract

The crescent spot shape observed in DIII-D runaway electron synchrotron radiation images is shown to result from the high degree of anisotropy in the emitted radiation, the finite spectral range of the camera and the distribution of runaways. The finite spectral camera range is found to be particularly important, as the radiation from the high-field side can be stronger by a factor $10^6$ than the radiation from the low-field side in DIII-D. By combining a kinetic model of the runaway dynamics with a synthetic synchrotron diagnostic we see that physical processes not described by the kinetic model (such as radial transport) are likely to be limiting the energy of the runaways. We show that a population of runaways with lower dominant energies and larger pitch-angles than those predicted by the kinetic model provide a better match to the synchrotron measurements. Using a new synthetic bremsstrahlung diagnostic we also simulate the view of the Gamma Ray Imager (GRI) diagnostic used at DIII-D to resolve the spatial distribution of runaway-generated bremsstrahlung., Comment: 21 pages, 11 figures

Published
2017
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24. Acetone Sensing Properties of Nanostructured Copper Oxide Films on Glass Substrate

Author

Cretu, V., Ababii, N., Postica, V., Magariu, N., Hoppe, M., Verjbitki, V., Sontea, V., Adelung, R., Lupan, O., Magjarevic, Ratko, Series Editor, Ładyżyński, Piotr, Associate Editor, Ibrahim, Fatimah, Associate Editor, Lackovic, Igor, Associate Editor, Rock, Emilio Sacristan, Associate Editor, Tiginyanu, Ion, editor, Sontea, Victor, editor, and Railean, Serghei, editor

Published
2020
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25. Sensorial and Local Reflectivity Properties of the Columnar ZnO:Eu Films

Author

Lupan, C., Schütt, A., Bîrnaz, A., Hoppe, M., Adelung, R., Magjarevic, Ratko, Series Editor, Ładyżyński, Piotr, Associate Editor, Ibrahim, Fatimah, Associate Editor, Lackovic, Igor, Associate Editor, Rock, Emilio Sacristan, Associate Editor, Tiginyanu, Ion, editor, Sontea, Victor, editor, and Railean, Serghei, editor

Published
2020
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30. Photocatalytic Applications of Doped Zinc Oxide Porous Films Grown by Magnetron Sputtering

Author

Ghimpu, L., Reimer, T., Smazna, D., Hoppe, M., Benecke, W., Bejenari, A., Cojocaru, A., Lupan, O., Adelung, R., Tiginyanu, I., Magjarevic, Ratko, Editor-in-chief, Ładyżyński, Piotr, Series editor, Ibrahim, Fatimah, Series editor, Lacković, Igor, Series editor, Rock, Emilio Sacristan, Series editor, Sontea, Victor, editor, and Tiginyanu, Ion, editor

Published
2016
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31. Functional Ecofriendly Coatings for Marine Applications

Author

Hölken, I., Hoppe, M., Adelung, R., Baum, M., Magjarevic, Ratko, Editor-in-chief, Ładyżyński, Piotr, Series editor, Ibrahim, Fatimah, Series editor, Lacković, Igor, Series editor, Rock, Emilio Sacristan, Series editor, Sontea, Victor, editor, and Tiginyanu, Ion, editor

Published
2016
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35. Overview of the TCV tokamak experimental programme

Author

Reimerdes, H, Agostini, M, Alessi, E, Alberti, S, Andrebe, Y, Arnichand, H, Balbin, J, Bagnato, F, Baquero-Ruiz, M, Bernert, M, Bin, W, Blanchard, P, Blanken, T, Boedo, J, Brida, D, Brunner, S, Bogar, C, Bogar, O, Bolzonella, T, Bombarda, F, Bouquey, F, Bowman, C, Brunetti, D, Buermans, J, Bufferand, H, Calacci, L, Camenen, Y, Carli, S, Carnevale, D, Carpanese, F, Causa, F, Cavalier, J, Cavedon, M, Cazabonne, J, Cerovsky, J, Chandra, R, Chandrarajan Jayalekshmi, A, Chellai, O, Chmielewski, P, Choi, D, Ciraolo, G, Classen, I, Coda, S, Colandrea, C, Dal Molin, A, David, P, De Baar, M, Decker, J, Dekeyser, W, De Oliveira, H, Douai, D, Dreval, M, Dunne, M, Duval, B, Elmore, S, Embreus, O, Eriksson, F, Faitsch, M, Falchetto, G, Farnik, M, Fasoli, A, Fedorczak, N, Felici, F, Fevrier, O, Ficker, O, Fil, A, Fontana, M, Fransson, E, Frassinetti, L, Furno, I, Gahle, D, Galassi, D, Galazka, K, Galperti, C, Garavaglia, S, Garcia-Munoz, M, Geiger, B, Giacomin, M, Giruzzi, G, Gobbin, M, Golfinopoulos, T, Goodman, T, Gorno, S, Granucci, G, Graves, J, Griener, M, Gruca, M, Gyergyek, T, Haelterman, R, Hakola, A, Han, W, Happel, T, Harrer, G, Harrison, J, Henderson, S, Hogeweij, G, Hogge, J, Hoppe, M, Horacek, J, Huang, Z, Iantchenko, A, Innocente, P, Insulander Bjork, K, Ionita-Schrittweiser, C, Isliker, H, Jardin, A, Jaspers, R, Karimov, R, Karpushov, A, Kazakov, Y, Komm, M, Kong, M, Kovacic, J, Krutkin, O, Kudlacek, O, Kumar, U, Kwiatkowski, R, Labit, B, Laguardia, L, Lammers, J, Laribi, E, Laszynska, E, Lazaros, A, Linder, O, Linehan, B, Lipschultz, B, Llobet, X, Loizu, J, Lunt, T, Macusova, E, Marandet, Y, Maraschek, M, Marceca, G, Marchetto, C, Marchioni, S, Marmar, E, Martin, Y, Martinelli, L, Matos, F, Maurizio, R, Mayoral, M, Mazon, D, Menkovski, V, Merle, A, Merlo, G, Meyer, H, Mikszuta-Michalik, K, Molina Cabrera, P, Morales, J, Moret, J, Moro, A, Moulton, D, Muhammed, H, Myatra, O, Mykytchuk, D, Napoli, F, Nem, R, Nielsen, A, Nocente, M, Nowak, S, Offeddu, N, Olsen, J, Orsitto, F, Pan, O, Papp, G, Pau, A, Perek, A, Pesamosca, F, Peysson, Y, Pigatto, L, Piron, C, Poradzinski, M, Porte, L, Putterich, T, Rabinski, M, Raj, H, Rasmussen, J, Ratta, G, Ravensbergen, T, Ricci, D, Ricci, P, Rispoli, N, Riva, F, Rivero-Rodriguez, J, Salewski, M, Sauter, O, Schmidt, B, Schrittweiser, R, Sharapov, S, Sheikh, U, Sieglin, B, Silva, M, Smolders, A, Snicker, A, Sozzi, C, Spolaore, M, Stagni, A, Stipani, L, Sun, G, Tala, T, Tamain, P, Tanaka, K, Tema Biwole, A, Terranova, D, Terry, J, Testa, D, Theiler, C, Thornton, A, Thrysoe, A, Torreblanca, H, Tsui, C, Vaccaro, D, Vallar, M, Van Berkel, M, Van Eester, D, Van Kampen, R, Van Mulders, S, Verhaegh, K, Verhaeghe, T, Vianello, N, Villone, F, Viezzer, E, Vincent, B, Voitsekhovitch, I, Vu, N, Walkden, N, Wauters, T, Weisen, H, Wendler, N, Wensing, M, Widmer, F, Wiesen, S, Wischmeier, M, Wijkamp, T, Wunderlich, D, Wuthrich, C, Yanovskiy, V, Zebrowski, J, Reimerdes H., Agostini M., Alessi E., Alberti S., Andrebe Y., Arnichand H., Balbin J., Bagnato F., Baquero-Ruiz M., Bernert M., Bin W., Blanchard P., Blanken T. C., Boedo J. A., Brida D., Brunner S., Bogar C., Bogar O., Bolzonella T., Bombarda F., Bouquey F., Bowman C., Brunetti D., Buermans J., Bufferand H., Calacci L., Camenen Y., Carli S., Carnevale D., Carpanese F., Causa F., Cavalier J., Cavedon M., Cazabonne J. A., Cerovsky J., Chandra R., Chandrarajan Jayalekshmi A., Chellai O., Chmielewski P., Choi D., Ciraolo G., Classen I. G. J., Coda S., Colandrea C., Dal Molin A., David P., De Baar M. R., Decker J., Dekeyser W., De Oliveira H., Douai D., Dreval M., Dunne M. G., Duval B. P., Elmore S., Embreus O., Eriksson F., Faitsch M., Falchetto G., Farnik M., Fasoli A., Fedorczak N., Felici F., Fevrier O., Ficker O., Fil A., Fontana M., Fransson E., Frassinetti L., Furno I., Gahle D. S., Galassi D., Galazka K., Galperti C., Garavaglia S., Garcia-Munoz M., Geiger B., Giacomin M., Giruzzi G., Gobbin M., Golfinopoulos T., Goodman T., Gorno S., Granucci G., Graves J. P., Griener M., Gruca M., Gyergyek T., Haelterman R., Hakola A., Han W., Happel T., Harrer G., Harrison J. R., Henderson S., Hogeweij G. M. D., Hogge J. -P., Hoppe M., Horacek J., Huang Z., Iantchenko A., Innocente P., Insulander Bjork K., Ionita-Schrittweiser C., Isliker H., Jardin A., Jaspers R. J. E., Karimov R., Karpushov A. N., Kazakov Y., Komm M., Kong M., Kovacic J., Krutkin O., Kudlacek O., Kumar U., Kwiatkowski R., Labit B., Laguardia L., Lammers J. T., Laribi E., Laszynska E., Lazaros A., Linder O., Linehan B., Lipschultz B., Llobet X., Loizu J., Lunt T., Macusova E., Marandet Y., Maraschek M., Marceca G., Marchetto C., Marchioni S., Marmar E. S., Martin Y., Martinelli L., Matos F., Maurizio R., Mayoral M. -L., Mazon D., Menkovski V., Merle A., Merlo G., Meyer H., Mikszuta-Michalik K., Molina Cabrera P. A., Morales J., Moret J. -M., Moro A., Moulton D., Muhammed H., Myatra O., Mykytchuk D., Napoli F., Nem R. D., Nielsen A. H., Nocente M., Nowak S., Offeddu N., Olsen J., Orsitto F. P., Pan O., Papp G., Pau A., Perek A., Pesamosca F., Peysson Y., Pigatto L., Piron C., Poradzinski M., Porte L., Putterich T., Rabinski M., Raj H., Rasmussen J. J., Ratta G. A., Ravensbergen T., Ricci D., Ricci P., Rispoli N., Riva F., Rivero-Rodriguez J. F., Salewski M., Sauter O., Schmidt B. S., Schrittweiser R., Sharapov S., Sheikh U. A., Sieglin B., Silva M., Smolders A., Snicker A., Sozzi C., Spolaore M., Stagni A., Stipani L., Sun G., Tala T., Tamain P., Tanaka K., Tema Biwole A., Terranova D., Terry J. L., Testa D., Theiler C., Thornton A., Thrysoe A., Torreblanca H., Tsui C. K., Vaccaro D., Vallar M., Van Berkel M., Van Eester D., Van Kampen R. J. R., Van Mulders S., Verhaegh K., Verhaeghe T., Vianello N., Villone F., Viezzer E., Vincent B., Voitsekhovitch I., Vu N. M. T., Walkden N., Wauters T., Weisen H., Wendler N., Wensing M., Widmer F., Wiesen S., Wischmeier M., Wijkamp T. A., Wunderlich D., Wuthrich C., Yanovskiy V., Zebrowski J., Reimerdes, H, Agostini, M, Alessi, E, Alberti, S, Andrebe, Y, Arnichand, H, Balbin, J, Bagnato, F, Baquero-Ruiz, M, Bernert, M, Bin, W, Blanchard, P, Blanken, T, Boedo, J, Brida, D, Brunner, S, Bogar, C, Bogar, O, Bolzonella, T, Bombarda, F, Bouquey, F, Bowman, C, Brunetti, D, Buermans, J, Bufferand, H, Calacci, L, Camenen, Y, Carli, S, Carnevale, D, Carpanese, F, Causa, F, Cavalier, J, Cavedon, M, Cazabonne, J, Cerovsky, J, Chandra, R, Chandrarajan Jayalekshmi, A, Chellai, O, Chmielewski, P, Choi, D, Ciraolo, G, Classen, I, Coda, S, Colandrea, C, Dal Molin, A, David, P, De Baar, M, Decker, J, Dekeyser, W, De Oliveira, H, Douai, D, Dreval, M, Dunne, M, Duval, B, Elmore, S, Embreus, O, Eriksson, F, Faitsch, M, Falchetto, G, Farnik, M, Fasoli, A, Fedorczak, N, Felici, F, Fevrier, O, Ficker, O, Fil, A, Fontana, M, Fransson, E, Frassinetti, L, Furno, I, Gahle, D, Galassi, D, Galazka, K, Galperti, C, Garavaglia, S, Garcia-Munoz, M, Geiger, B, Giacomin, M, Giruzzi, G, Gobbin, M, Golfinopoulos, T, Goodman, T, Gorno, S, Granucci, G, Graves, J, Griener, M, Gruca, M, Gyergyek, T, Haelterman, R, Hakola, A, Han, W, Happel, T, Harrer, G, Harrison, J, Henderson, S, Hogeweij, G, Hogge, J, Hoppe, M, Horacek, J, Huang, Z, Iantchenko, A, Innocente, P, Insulander Bjork, K, Ionita-Schrittweiser, C, Isliker, H, Jardin, A, Jaspers, R, Karimov, R, Karpushov, A, Kazakov, Y, Komm, M, Kong, M, Kovacic, J, Krutkin, O, Kudlacek, O, Kumar, U, Kwiatkowski, R, Labit, B, Laguardia, L, Lammers, J, Laribi, E, Laszynska, E, Lazaros, A, Linder, O, Linehan, B, Lipschultz, B, Llobet, X, Loizu, J, Lunt, T, Macusova, E, Marandet, Y, Maraschek, M, Marceca, G, Marchetto, C, Marchioni, S, Marmar, E, Martin, Y, Martinelli, L, Matos, F, Maurizio, R, Mayoral, M, Mazon, D, Menkovski, V, Merle, A, Merlo, G, Meyer, H, Mikszuta-Michalik, K, Molina Cabrera, P, Morales, J, Moret, J, Moro, A, Moulton, D, Muhammed, H, Myatra, O, Mykytchuk, D, Napoli, F, Nem, R, Nielsen, A, Nocente, M, Nowak, S, Offeddu, N, Olsen, J, Orsitto, F, Pan, O, Papp, G, Pau, A, Perek, A, Pesamosca, F, Peysson, Y, Pigatto, L, Piron, C, Poradzinski, M, Porte, L, Putterich, T, Rabinski, M, Raj, H, Rasmussen, J, Ratta, G, Ravensbergen, T, Ricci, D, Ricci, P, Rispoli, N, Riva, F, Rivero-Rodriguez, J, Salewski, M, Sauter, O, Schmidt, B, Schrittweiser, R, Sharapov, S, Sheikh, U, Sieglin, B, Silva, M, Smolders, A, Snicker, A, Sozzi, C, Spolaore, M, Stagni, A, Stipani, L, Sun, G, Tala, T, Tamain, P, Tanaka, K, Tema Biwole, A, Terranova, D, Terry, J, Testa, D, Theiler, C, Thornton, A, Thrysoe, A, Torreblanca, H, Tsui, C, Vaccaro, D, Vallar, M, Van Berkel, M, Van Eester, D, Van Kampen, R, Van Mulders, S, Verhaegh, K, Verhaeghe, T, Vianello, N, Villone, F, Viezzer, E, Vincent, B, Voitsekhovitch, I, Vu, N, Walkden, N, Wauters, T, Weisen, H, Wendler, N, Wensing, M, Widmer, F, Wiesen, S, Wischmeier, M, Wijkamp, T, Wunderlich, D, Wuthrich, C, Yanovskiy, V, Zebrowski, J, Reimerdes H., Agostini M., Alessi E., Alberti S., Andrebe Y., Arnichand H., Balbin J., Bagnato F., Baquero-Ruiz M., Bernert M., Bin W., Blanchard P., Blanken T. C., Boedo J. A., Brida D., Brunner S., Bogar C., Bogar O., Bolzonella T., Bombarda F., Bouquey F., Bowman C., Brunetti D., Buermans J., Bufferand H., Calacci L., Camenen Y., Carli S., Carnevale D., Carpanese F., Causa F., Cavalier J., Cavedon M., Cazabonne J. A., Cerovsky J., Chandra R., Chandrarajan Jayalekshmi A., Chellai O., Chmielewski P., Choi D., Ciraolo G., Classen I. G. J., Coda S., Colandrea C., Dal Molin A., David P., De Baar M. R., Decker J., Dekeyser W., De Oliveira H., Douai D., Dreval M., Dunne M. G., Duval B. P., Elmore S., Embreus O., Eriksson F., Faitsch M., Falchetto G., Farnik M., Fasoli A., Fedorczak N., Felici F., Fevrier O., Ficker O., Fil A., Fontana M., Fransson E., Frassinetti L., Furno I., Gahle D. S., Galassi D., Galazka K., Galperti C., Garavaglia S., Garcia-Munoz M., Geiger B., Giacomin M., Giruzzi G., Gobbin M., Golfinopoulos T., Goodman T., Gorno S., Granucci G., Graves J. P., Griener M., Gruca M., Gyergyek T., Haelterman R., Hakola A., Han W., Happel T., Harrer G., Harrison J. R., Henderson S., Hogeweij G. M. D., Hogge J. -P., Hoppe M., Horacek J., Huang Z., Iantchenko A., Innocente P., Insulander Bjork K., Ionita-Schrittweiser C., Isliker H., Jardin A., Jaspers R. J. E., Karimov R., Karpushov A. N., Kazakov Y., Komm M., Kong M., Kovacic J., Krutkin O., Kudlacek O., Kumar U., Kwiatkowski R., Labit B., Laguardia L., Lammers J. T., Laribi E., Laszynska E., Lazaros A., Linder O., Linehan B., Lipschultz B., Llobet X., Loizu J., Lunt T., Macusova E., Marandet Y., Maraschek M., Marceca G., Marchetto C., Marchioni S., Marmar E. S., Martin Y., Martinelli L., Matos F., Maurizio R., Mayoral M. -L., Mazon D., Menkovski V., Merle A., Merlo G., Meyer H., Mikszuta-Michalik K., Molina Cabrera P. A., Morales J., Moret J. -M., Moro A., Moulton D., Muhammed H., Myatra O., Mykytchuk D., Napoli F., Nem R. D., Nielsen A. H., Nocente M., Nowak S., Offeddu N., Olsen J., Orsitto F. P., Pan O., Papp G., Pau A., Perek A., Pesamosca F., Peysson Y., Pigatto L., Piron C., Poradzinski M., Porte L., Putterich T., Rabinski M., Raj H., Rasmussen J. J., Ratta G. A., Ravensbergen T., Ricci D., Ricci P., Rispoli N., Riva F., Rivero-Rodriguez J. F., Salewski M., Sauter O., Schmidt B. S., Schrittweiser R., Sharapov S., Sheikh U. A., Sieglin B., Silva M., Smolders A., Snicker A., Sozzi C., Spolaore M., Stagni A., Stipani L., Sun G., Tala T., Tamain P., Tanaka K., Tema Biwole A., Terranova D., Terry J. L., Testa D., Theiler C., Thornton A., Thrysoe A., Torreblanca H., Tsui C. K., Vaccaro D., Vallar M., Van Berkel M., Van Eester D., Van Kampen R. J. R., Van Mulders S., Verhaegh K., Verhaeghe T., Vianello N., Villone F., Viezzer E., Vincent B., Voitsekhovitch I., Vu N. M. T., Walkden N., Wauters T., Weisen H., Wendler N., Wensing M., Widmer F., Wiesen S., Wischmeier M., Wijkamp T. A., Wunderlich D., Wuthrich C., Yanovskiy V., and Zebrowski J.

Abstract

The tokamak à configuration variable (TCV) continues to leverage its unique shaping capabilities, flexible heating systems and modern control system to address critical issues in preparation for ITER and a fusion power plant. For the 2019-20 campaign its configurational flexibility has been enhanced with the installation of removable divertor gas baffles, its diagnostic capabilities with an extensive set of upgrades and its heating systems with new dual frequency gyrotrons. The gas baffles reduce coupling between the divertor and the main chamber and allow for detailed investigations on the role of fuelling in general and, together with upgraded boundary diagnostics, test divertor and edge models in particular. The increased heating capabilities broaden the operational regime to include Te/Ti ∼1 and have stimulated refocussing studies from L-mode to H-mode across a range of research topics. ITER baseline parameters were reached in type-I ELMy H-modes and alternative regimes with 'small' (or no) ELMs explored. Most prominently, negative triangularity was investigated in detail and confirmed as an attractive scenario with H-mode level core confinement but an L-mode edge. Emphasis was also placed on control, where an increased number of observers, actuators and control solutions became available and are now integrated into a generic control framework as will be needed in future devices. The quantity and quality of results of the 2019-20 TCV campaign are a testament to its successful integration within the European research effort alongside a vibrant domestic programme and international collaborations.

Published
2022

37. Exceptionally high-temperature in-air stability of transparent conductive oxide tantalum-doped tin dioxide

Author

(0000-0003-3408-3572) Krause, M., Hoppe, M., Romero-Muñiz, C., Mendez, A., (0000-0003-2506-6869) Munnik, F., (0000-0002-5238-6465) Garcia Valenzuela, A., Schimpf, C., Rafaja, D., Escobar-Galindo, R., (0000-0003-3408-3572) Krause, M., Hoppe, M., Romero-Muñiz, C., Mendez, A., (0000-0003-2506-6869) Munnik, F., (0000-0002-5238-6465) Garcia Valenzuela, A., Schimpf, C., Rafaja, D., and Escobar-Galindo, R.

Abstract

The compositional, optical and structural stability of transparent conductive oxide SnO2:Ta (1.25 at.% Ta) thin films at 650 °C and 800 °C in air was studied under isothermal conditions. After the high-temperature treatment, the element composition and the optical spectra of the material were unchanged. The X-ray diffraction confirmed the conservation of a single rutile-type phase. Two strong Raman lines located out of the SnO2 phonon range indicated point defects in the material, which were identified as Sn vacancies and O interstitials by theoretical calculations. These point defects were partially healed out during the high-temperature treatment, without affecting the transmittance and reflectance of the material. Our study demonstrates an exceptional high in-air stability of Ta-doped SnO2 and encourages it for applications in fields, where transparent conductive oxides with high-temperature and oxidation stability are required. These are, e.g., selective transmitters for concentrated solar power or electrodes for dye-sensitized solar cells and dynamic random-access memories.

Published
2023

38. Academic Misfits

Author

Hoppe, M., Siegert, S., Temiz, S., Seifan, F., Hasselgren, Anton, Hoppe, M., Siegert, S., Temiz, S., Seifan, F., and Hasselgren, Anton

Abstract

What makes an academic? Is it their unyielding devotion to research and teaching, their tendency towards a hermitic existence? Or does it have more to do with their socioeconomic privilege and racial profile? Are academics today any different from what society has always known them to be? How homogenous is the group of academics? Historically, academia was populated by men from the upper classes, often somewhat similar to each other. Over time, structures and procedures were established to ensure both scientific quality and academic exclusion. This chapter deconstructs the myths surrounding academics and the lives they lead within academia. Through shards of broken mirrors is the reader encouraged to look at a group of misfits that are the odd one out in most academic contexts that defy common classifications. Misfits that would like to devote only 40 working hours to academia instead of their whole being. Misfits that use the “wrong” theoretical lenses, unpopular methods, or undesirable contexts. Misfits that don't fit in by matter of race, ethnicity, sex, or social economic class. Misfits that have found their misfitting family and hold on for dear life.

Published
2023
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48. Galileo Timing for R-Mode – Testing Campaign

Author

Cueto-Felgueroso, G., primary, Martínez, J., additional, Blesa, S., additional, Moreno, G., additional, López, M., additional, Nieto, R., additional, Píriz, R., additional, Hoppe, M., additional, Gewies, S., additional, and Callewaert, K., additional

Published
2022
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49. EEG in Epilepsy

Author

Hoppe, M., Wennberg, R., Tai, P., Pohlmann-Eden, B., Lozano, Andres M., editor, Gildenberg, Philip L., editor, and Tasker, Ronald R., editor

Published
2009
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50. Millimeter-wave beam scattering and induced broadening by plasma turbulence in the TCV tokamak

Author

Chellai, O, Alberti, S, Furno, I, Goodman, T, Maj, O, Merlo, G, Poli, E, Ricci, P, Riva, F, Weber, H, Coda, S, Agostini, M, Albanese, R, Alessi, E, Allan, S, Allcock, J, Ambrosino, R, Anand, H, Andrebe, Y, Arnichand, H, Auriemma, F, Ayllon-Guerola, J, Bagnato, F, Ball, J, Baquero-Ruiz, M, Beletskii, A, Bernert, M, Bin, W, Blanchard, P, Blanken, T, Boedo, J, Bogar, O, Bolzonella, T, Bombarda, F, Bonanomi, N, Bouquey, F, Bowman, C, Brida, D, Bucalossi, J, Buermans, J, Bufferand, H, Buratti, P, Calabro, G, Calacci, L, Camenen, Y, Carnevale, D, Carpanese, F, Carr, M, Carraro, L, Casolari, A, Causa, F, Cerovsky, J, Chmielewski, P, Choi, D, Christen, N, Ciraolo, G, Cordaro, L, Costea, S, Cruz, N, Czarnecka, A, Dal Molin, A, David, P, Decker, J, De Oliveira, H, Douai, D, Dreval, M, Dudson, B, Dunne, M, Duval, B, Eich, T, Elmore, S, Embreus, O, Esposito, B, Faitsch, M, Farnik, M, Fasoli, A, Fedorczak, N, Felici, F, Feng, S, Feng, X, Ferro, G, Fevrier, O, Ficker, O, Fil, A, Fontana, M, Frassinetti, L, Gahle, D, Galassi, D, Galazka, K, Gallo, A, Galperti, C, Garavaglia, S, Garcia, J, Garcia-Munoz, M, Garrido, A, Garrido, I, Gath, J, Geiger, B, Giruzzi, G, Gobbin, M, Gorini, G, Gospodarczyk, M, Granucci, G, Graves, J, Gruca, M, Gyergyek, T, Hakola, A, Happel, T, Harrer, G, Harrison, J, Havlickova, E, Hawke, J, Henderson, S, Hennequin, P, Hesslow, L, Hogeweij, D, Hogge, J, Hopf, C, Hoppe, M, Horacek, J, Huang, Z, Hubbard, A, Iantchenko, A, Igochine, V, Innocente, P, Ionita Schrittwieser, C, Isliker, H, Jacquier, R, Jardin, A, Kappatou, A, Karpushov, A, Kazantzidis, P, Keeling, D, Kirneva, N, Komm, M, Kong, M, Kovacic, J, Krawczyk, N, Kudlacek, O, Kurki-Suonio, T, Kwiatkowski, R, Labit, B, Lazzaro, E, Linehan, B, Lipschultz, B, Llobet, X, Lombroni, R, Loschiavo, V, Lunt, T, Macusova, E, Madsen, J, Maljaars, E, Mantica, P, Maraschek, M, Marchetto, C, Marco, A, Mariani, A, Marini, C, Martin, Y, Matos, F, Maurizio, R, Mavkov, B, Mazon, D, Mccarthy, P, Mcdermott, R, Menkovski, V, Merle, A, Meyer, H, Micheletti, D, Militello, F, Mitosinkova, K, Mlynar, J, Moiseenko, V, Molina Cabrera, P, Morales, J, Moret, J, Moro, A, Mumgaard, R, Naulin, V, Nem, R, Nespoli, F, Nielsen, A, Nielsen, S, Nocente, M, Nowak, S, Offeddu, N, Orsitto, F, Paccagnella, R, Palha, A, Papp, G, Pau, A, Pavlichenko, R, Perek, A, Pericoli Ridolfini, V, Pesamosca, F, Piergotti, V, Pigatto, L, Piovesan, P, Piron, C, Plyusnin, V, Porte, L, Pucella, G, Puiatti, M, Putterich, T, Rabinski, M, Juul Rasmussen, J, Ravensbergen, T, Reich, M, Reimerdes, H, Reimold, F, Reux, C, Ricci, D, Rispoli, N, Rosato, J, Saarelma, S, Salewski, M, Salmi, A, Sauter, O, Scheffer, M, Schlatter, C, Schneider, B, Schrittwieser, R, Sharapov, S, Sheeba, R, Sheikh, U, Shousha, R, Silva, M, Sinha, J, Sozzi, C, Spolaore, M, Stipani, L, Strand, P, Tala, T, Tema Biwole, A, Teplukhina, A, Testa, D, Theiler, C, Thornton, A, Tomaz, G, Tomes, M, Tran, M, Tsironis, C, Tsui, C, Urban, J, Valisa, M, Vallar, M, Van Vugt, D, Vartanian, S, Vasilovici, O, Verhaegh, K, Vermare, L, Vianello, N, Viezzer, E, Vijvers, W, Villone, F, Voitsekhovitch, I, Vu, N, Walkden, N, Wauters, T, Weiland, M, Weisen, H, Wensing, M, Wiesenberger, M, Wilkie, G, Wischmeier, M, Wu, K, Yoshida, M, Zagorski, R, Zanca, P, Zebrowski, J, Zisis, A, Zuin, M, Chellai O., Alberti S., Furno I., Goodman T. P., Maj O., Merlo G., Poli E., Ricci P., Riva F., Weber H., Coda S., Agostini M., Albanese R., Alessi E., Allan S., Allcock J., Ambrosino R., Anand H., Andrebe Y., Arnichand H., Auriemma F., Ayllon-Guerola J. M., Bagnato F., Ball J., Baquero-Ruiz M., Beletskii A. A., Bernert M., Bin W., Blanchard P., Blanken T. C., Boedo J. A., Bogar O., Bolzonella T., Bombarda F., Bonanomi N., Bouquey F., Bowman C., Brida D., Bucalossi J., Buermans J., Bufferand H., Buratti P., Calabro G., Calacci L., Camenen Y., Carnevale D., Carpanese F., Carr M., Carraro L., Casolari A., Causa F., Cerovsky J., Chmielewski P., Choi D., Christen N., Ciraolo G., Cordaro L., Costea S., Cruz N., Czarnecka A., Dal Molin A., David P., Decker J., De Oliveira H., Douai D., Dreval M. B., Dudson B., Dunne M., Duval B. P., Eich T., Elmore S., Embreus O., Esposito B., Faitsch M., Farnik M., Fasoli A., Fedorczak N., Felici F., Feng S., Feng X., Ferro G., Fevrier O., Ficker O., Fil A., Fontana M., Frassinetti L., Gahle D. S., Galassi D., Galazka K., Gallo A., Galperti C., Garavaglia S., Garcia J., Garcia-Munoz M., Garrido A. J., Garrido I., Gath J., Geiger B., Giruzzi G., Gobbin M., Gorini G., Gospodarczyk M., Granucci G., Graves J. P., Gruca M., Gyergyek T., Hakola A., Happel T., Harrer G. F., Harrison J., Havlickova E., Hawke J., Henderson S., Hennequin P., Hesslow L., Hogeweij D., Hogge J. -Ph., Hopf C., Hoppe M., Horacek J., Huang Z., Hubbard A., Iantchenko A., Igochine V., Innocente P., Ionita Schrittwieser C., Isliker H., Jacquier R., Jardin A., Kappatou A., Karpushov A., Kazantzidis P. -V., Keeling D., Kirneva N., Komm M., Kong M., Kovacic J., Krawczyk N., Kudlacek O., Kurki-Suonio T., Kwiatkowski R., Labit B., Lazzaro E., Linehan B., Lipschultz B., Llobet X., Lombroni R., Loschiavo V. P., Lunt T., MacUsova E., Madsen J., Maljaars E., Mantica P., Maraschek M., Marchetto C., Marco A., Mariani A., Marini C., Martin Y., Matos F., Maurizio R., Mavkov B., Mazon D., McCarthy P., McDermott R., Menkovski V., Merle A., Meyer H., Micheletti D., Militello F., Mitosinkova K., Mlynar J., Moiseenko V., Molina Cabrera P. A., Morales J., Moret J. -M., Moro A., Mumgaard R. T., Naulin V., Nem R. D., Nespoli F., Nielsen A. H., Nielsen S. K., Nocente M., Nowak S., Offeddu N., Orsitto F. P., Paccagnella R., Palha A., Papp G., Pau A., Pavlichenko R. O., Perek A., Pericoli Ridolfini V., Pesamosca F., Piergotti V., Pigatto L., Piovesan P., Piron C., Plyusnin V., Porte L., Pucella G., Puiatti M. E., Putterich T., Rabinski M., Juul Rasmussen J., Ravensbergen T., Reich M., Reimerdes H., Reimold F., Reux C., Ricci D., Rispoli N., Rosato J., Saarelma S., Salewski M., Salmi A., Sauter O., Scheffer M., Schlatter Ch., Schneider B. S., Schrittwieser R., Sharapov S., Sheeba R. R., Sheikh U., Shousha R., Silva M., Sinha J., Sozzi C., Spolaore M., Stipani L., Strand P., Tala T., Tema Biwole A. S., Teplukhina A. A., Testa D., Theiler C., Thornton A., Tomaz G., Tomes M., Tran M. Q., Tsironis C., Tsui C. K., Urban J., Valisa M., Vallar M., Van Vugt D., Vartanian S., Vasilovici O., Verhaegh K., Vermare L., Vianello N., Viezzer E., Vijvers W. A. J., Villone F., Voitsekhovitch I., Vu N. M. T., Walkden N., Wauters T., Weiland M., Weisen H., Wensing M., Wiesenberger M., Wilkie G., Wischmeier M., Wu K., Yoshida M., Zagorski R., Zanca P., Zebrowski J., Zisis A., Zuin M., Chellai, O, Alberti, S, Furno, I, Goodman, T, Maj, O, Merlo, G, Poli, E, Ricci, P, Riva, F, Weber, H, Coda, S, Agostini, M, Albanese, R, Alessi, E, Allan, S, Allcock, J, Ambrosino, R, Anand, H, Andrebe, Y, Arnichand, H, Auriemma, F, Ayllon-Guerola, J, Bagnato, F, Ball, J, Baquero-Ruiz, M, Beletskii, A, Bernert, M, Bin, W, Blanchard, P, Blanken, T, Boedo, J, Bogar, O, Bolzonella, T, Bombarda, F, Bonanomi, N, Bouquey, F, Bowman, C, Brida, D, Bucalossi, J, Buermans, J, Bufferand, H, Buratti, P, Calabro, G, Calacci, L, Camenen, Y, Carnevale, D, Carpanese, F, Carr, M, Carraro, L, Casolari, A, Causa, F, Cerovsky, J, Chmielewski, P, Choi, D, Christen, N, Ciraolo, G, Cordaro, L, Costea, S, Cruz, N, Czarnecka, A, Dal Molin, A, David, P, Decker, J, De Oliveira, H, Douai, D, Dreval, M, Dudson, B, Dunne, M, Duval, B, Eich, T, Elmore, S, Embreus, O, Esposito, B, Faitsch, M, Farnik, M, Fasoli, A, Fedorczak, N, Felici, F, Feng, S, Feng, X, Ferro, G, Fevrier, O, Ficker, O, Fil, A, Fontana, M, Frassinetti, L, Gahle, D, Galassi, D, Galazka, K, Gallo, A, Galperti, C, Garavaglia, S, Garcia, J, Garcia-Munoz, M, Garrido, A, Garrido, I, Gath, J, Geiger, B, Giruzzi, G, Gobbin, M, Gorini, G, Gospodarczyk, M, Granucci, G, Graves, J, Gruca, M, Gyergyek, T, Hakola, A, Happel, T, Harrer, G, Harrison, J, Havlickova, E, Hawke, J, Henderson, S, Hennequin, P, Hesslow, L, Hogeweij, D, Hogge, J, Hopf, C, Hoppe, M, Horacek, J, Huang, Z, Hubbard, A, Iantchenko, A, Igochine, V, Innocente, P, Ionita Schrittwieser, C, Isliker, H, Jacquier, R, Jardin, A, Kappatou, A, Karpushov, A, Kazantzidis, P, Keeling, D, Kirneva, N, Komm, M, Kong, M, Kovacic, J, Krawczyk, N, Kudlacek, O, Kurki-Suonio, T, Kwiatkowski, R, Labit, B, Lazzaro, E, Linehan, B, Lipschultz, B, Llobet, X, Lombroni, R, Loschiavo, V, Lunt, T, Macusova, E, Madsen, J, Maljaars, E, Mantica, P, Maraschek, M, Marchetto, C, Marco, A, Mariani, A, Marini, C, Martin, Y, Matos, F, Maurizio, R, Mavkov, B, Mazon, D, Mccarthy, P, Mcdermott, R, Menkovski, V, Merle, A, Meyer, H, Micheletti, D, Militello, F, Mitosinkova, K, Mlynar, J, Moiseenko, V, Molina Cabrera, P, Morales, J, Moret, J, Moro, A, Mumgaard, R, Naulin, V, Nem, R, Nespoli, F, Nielsen, A, Nielsen, S, Nocente, M, Nowak, S, Offeddu, N, Orsitto, F, Paccagnella, R, Palha, A, Papp, G, Pau, A, Pavlichenko, R, Perek, A, Pericoli Ridolfini, V, Pesamosca, F, Piergotti, V, Pigatto, L, Piovesan, P, Piron, C, Plyusnin, V, Porte, L, Pucella, G, Puiatti, M, Putterich, T, Rabinski, M, Juul Rasmussen, J, Ravensbergen, T, Reich, M, Reimerdes, H, Reimold, F, Reux, C, Ricci, D, Rispoli, N, Rosato, J, Saarelma, S, Salewski, M, Salmi, A, Sauter, O, Scheffer, M, Schlatter, C, Schneider, B, Schrittwieser, R, Sharapov, S, Sheeba, R, Sheikh, U, Shousha, R, Silva, M, Sinha, J, Sozzi, C, Spolaore, M, Stipani, L, Strand, P, Tala, T, Tema Biwole, A, Teplukhina, A, Testa, D, Theiler, C, Thornton, A, Tomaz, G, Tomes, M, Tran, M, Tsironis, C, Tsui, C, Urban, J, Valisa, M, Vallar, M, Van Vugt, D, Vartanian, S, Vasilovici, O, Verhaegh, K, Vermare, L, Vianello, N, Viezzer, E, Vijvers, W, Villone, F, Voitsekhovitch, I, Vu, N, Walkden, N, Wauters, T, Weiland, M, Weisen, H, Wensing, M, Wiesenberger, M, Wilkie, G, Wischmeier, M, Wu, K, Yoshida, M, Zagorski, R, Zanca, P, Zebrowski, J, Zisis, A, Zuin, M, Chellai O., Alberti S., Furno I., Goodman T. P., Maj O., Merlo G., Poli E., Ricci P., Riva F., Weber H., Coda S., Agostini M., Albanese R., Alessi E., Allan S., Allcock J., Ambrosino R., Anand H., Andrebe Y., Arnichand H., Auriemma F., Ayllon-Guerola J. M., Bagnato F., Ball J., Baquero-Ruiz M., Beletskii A. A., Bernert M., Bin W., Blanchard P., Blanken T. C., Boedo J. A., Bogar O., Bolzonella T., Bombarda F., Bonanomi N., Bouquey F., Bowman C., Brida D., Bucalossi J., Buermans J., Bufferand H., Buratti P., Calabro G., Calacci L., Camenen Y., Carnevale D., Carpanese F., Carr M., Carraro L., Casolari A., Causa F., Cerovsky J., Chmielewski P., Choi D., Christen N., Ciraolo G., Cordaro L., Costea S., Cruz N., Czarnecka A., Dal Molin A., David P., Decker J., De Oliveira H., Douai D., Dreval M. B., Dudson B., Dunne M., Duval B. P., Eich T., Elmore S., Embreus O., Esposito B., Faitsch M., Farnik M., Fasoli A., Fedorczak N., Felici F., Feng S., Feng X., Ferro G., Fevrier O., Ficker O., Fil A., Fontana M., Frassinetti L., Gahle D. S., Galassi D., Galazka K., Gallo A., Galperti C., Garavaglia S., Garcia J., Garcia-Munoz M., Garrido A. J., Garrido I., Gath J., Geiger B., Giruzzi G., Gobbin M., Gorini G., Gospodarczyk M., Granucci G., Graves J. P., Gruca M., Gyergyek T., Hakola A., Happel T., Harrer G. F., Harrison J., Havlickova E., Hawke J., Henderson S., Hennequin P., Hesslow L., Hogeweij D., Hogge J. -Ph., Hopf C., Hoppe M., Horacek J., Huang Z., Hubbard A., Iantchenko A., Igochine V., Innocente P., Ionita Schrittwieser C., Isliker H., Jacquier R., Jardin A., Kappatou A., Karpushov A., Kazantzidis P. -V., Keeling D., Kirneva N., Komm M., Kong M., Kovacic J., Krawczyk N., Kudlacek O., Kurki-Suonio T., Kwiatkowski R., Labit B., Lazzaro E., Linehan B., Lipschultz B., Llobet X., Lombroni R., Loschiavo V. P., Lunt T., MacUsova E., Madsen J., Maljaars E., Mantica P., Maraschek M., Marchetto C., Marco A., Mariani A., Marini C., Martin Y., Matos F., Maurizio R., Mavkov B., Mazon D., McCarthy P., McDermott R., Menkovski V., Merle A., Meyer H., Micheletti D., Militello F., Mitosinkova K., Mlynar J., Moiseenko V., Molina Cabrera P. A., Morales J., Moret J. -M., Moro A., Mumgaard R. T., Naulin V., Nem R. D., Nespoli F., Nielsen A. H., Nielsen S. K., Nocente M., Nowak S., Offeddu N., Orsitto F. P., Paccagnella R., Palha A., Papp G., Pau A., Pavlichenko R. O., Perek A., Pericoli Ridolfini V., Pesamosca F., Piergotti V., Pigatto L., Piovesan P., Piron C., Plyusnin V., Porte L., Pucella G., Puiatti M. E., Putterich T., Rabinski M., Juul Rasmussen J., Ravensbergen T., Reich M., Reimerdes H., Reimold F., Reux C., Ricci D., Rispoli N., Rosato J., Saarelma S., Salewski M., Salmi A., Sauter O., Scheffer M., Schlatter Ch., Schneider B. S., Schrittwieser R., Sharapov S., Sheeba R. R., Sheikh U., Shousha R., Silva M., Sinha J., Sozzi C., Spolaore M., Stipani L., Strand P., Tala T., Tema Biwole A. S., Teplukhina A. A., Testa D., Theiler C., Thornton A., Tomaz G., Tomes M., Tran M. Q., Tsironis C., Tsui C. K., Urban J., Valisa M., Vallar M., Van Vugt D., Vartanian S., Vasilovici O., Verhaegh K., Vermare L., Vianello N., Viezzer E., Vijvers W. A. J., Villone F., Voitsekhovitch I., Vu N. M. T., Walkden N., Wauters T., Weiland M., Weisen H., Wensing M., Wiesenberger M., Wilkie G., Wischmeier M., Wu K., Yoshida M., Zagorski R., Zanca P., Zebrowski J., Zisis A., and Zuin M.

Abstract

The scattering of millimeter-wave beams from electron density fluctuations and the associated beam broadening are experimentally demonstrated. Using a dedicated setup, instantaneous deflection and (de-)focusing of the beam due to density blobs on the beam path are shown to agree with full-wave simulations. The detected time-averaged wave power transmitted through the turbulent plasma is reproduced by the radiative-transfer model implemented in the WKBeam code, which predicts a ∼50% turbulence-induced broadening of the beam cross-section. The role of core turbulence for the considered geometry is highlighted.

Published
2021

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