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51. Linearization of holomorphic families of algebraic automorphisms of the affine plane

Author

Kuroda, Shigeru, Kutzschebauch, Frank, and Pełka, Tomasz

Subjects
Mathematics - Algebraic Geometry, Mathematics - Complex Variables, 14R20, 32M05 (Primary) 14R10, 32M17, 32Q56 (Secondary)
Abstract

Let $G$ be a reductive group. We prove that a family of polynomial actions of $G$ on $\mathbb{C}^2$, holomorphically parametrized by an open Riemann surface, is linearizable. As an application, we show that a particular class of reductive group actions on $\mathbb{C}^3$ is linearizable. The main step of our proof is to establish a certain restrictive Oka property for groups of equivariant algebraic automorphisms of $\mathbb{C}^2$., Comment: 14 pages, to appear in Transformation Groups

Published
2020
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52. Pattern-based Long Short-term Memory for Mid-term Electrical Load Forecasting

Author

Pełka, Paweł and Dudek, Grzegorz

Subjects
Electrical Engineering and Systems Science - Signal Processing, Computer Science - Machine Learning, Statistics - Machine Learning
Abstract

This work presents a Long Short-Term Memory (LSTM) network for forecasting a monthly electricity demand time series with a one-year horizon. The novelty of this work is the use of pattern representation of the seasonal time series as an alternative to decomposition. Pattern representation simplifies the complex nonlinear and nonstationary time series, filtering out the trend and equalizing variance. Two types of patterns are defined: x-pattern and y-pattern. The former requires additional forecasting for the coding variables. The latter determines the coding variables from the process history. A hybrid approach based on x-patterns turned out to be more accurate than the standard LSTM approach based on a raw time series. In this combined approach an x-pattern is forecasted using a sequence-to-sequence LSTM network and the coding variables are forecasted using exponential smoothing. A simulation study performed on the monthly electricity demand time series for 35 European countries confirmed the high performance of the proposed model and its competitiveness to classical models such as ARIMA and exponential smoothing as well as the MLP neural network model., Comment: 8 pages, 10 figures

Published
2020

53. A Hybrid Residual Dilated LSTM end Exponential Smoothing Model for Mid-Term Electric Load Forecasting

Author

Dudek, Grzegorz, Pełka, Paweł, and Smyl, Slawek

Subjects
Electrical Engineering and Systems Science - Signal Processing, Computer Science - Machine Learning, Statistics - Machine Learning
Abstract

This work presents a hybrid and hierarchical deep learning model for mid-term load forecasting. The model combines exponential smoothing (ETS), advanced Long Short-Term Memory (LSTM) and ensembling. ETS extracts dynamically the main components of each individual time series and enables the model to learn their representation. Multi-layer LSTM is equipped with dilated recurrent skip connections and a spatial shortcut path from lower layers to allow the model to better capture long-term seasonal relationships and ensure more efficient training. A common learning procedure for LSTM and ETS, with a penalized pinball loss, leads to simultaneous optimization of data representation and forecasting performance. In addition, ensembling at three levels ensures a powerful regularization. A simulation study performed on the monthly electricity demand time series for 35 European countries confirmed the high performance of the proposed model and its competitiveness with classical models such as ARIMA and ETS as well as state-of-the-art models based on machine learning., Comment: 11 pages, 13 figures

Published
2020

54. Ensemble Forecasting of Monthly Electricity Demand using Pattern Similarity-based Methods

Author

Pełka, Paweł and Dudek, Grzegorz

Subjects
Computer Science - Machine Learning, Statistics - Machine Learning
Abstract

This work presents ensemble forecasting of monthly electricity demand using pattern similarity-based forecasting methods (PSFMs). PSFMs applied in this study include $k$-nearest neighbor model, fuzzy neighborhood model, kernel regression model, and general regression neural network. An integral part of PSFMs is a time series representation using patterns of time series sequences. Pattern representation ensures the input and output data unification through filtering a trend and equalizing variance. Two types of ensembles are created: heterogeneous and homogeneous. The former consists of different type base models, while the latter consists of a single-type base model. Five strategies are used for controlling a diversity of members in a homogeneous approach. The diversity is generated using different subsets of training data, different subsets of features, randomly disrupted input and output variables, and randomly disrupted model parameters. An empirical illustration applies the ensemble models as well as individual PSFMs for comparison to the monthly electricity demand forecasting for 35 European countries., Comment: 12 pages, 3 figures. arXiv admin note: text overlap with arXiv:2003.01475

Published
2020

55. Pattern Similarity-based Machine Learning Methods for Mid-term Load Forecasting: A Comparative Study

Author

Dudek, Grzegorz and Pełka, Paweł

Subjects
Computer Science - Machine Learning, Statistics - Machine Learning
Abstract

Pattern similarity-based methods are widely used in classification and regression problems. Repeated, similar-shaped cycles observed in seasonal time series encourage to apply these methods for forecasting. In this paper we use the pattern similarity-based methods for forecasting monthly electricity demand expressing annual seasonality. An integral part of the models is the time series representation using patterns of time series sequences. Pattern representation ensures the input and output data unification through trend filtering and variance equalization. Consequently, pattern representation simplifies the forecasting problem and allows us to use models based on pattern similarity. We consider four such models: nearest neighbor model, fuzzy neighborhood model, kernel regression model and general regression neural network. A regression function is constructed by aggregation output patterns with weights dependent on the similarity between input patterns. The advantages of the proposed models are: clear principle of operation, small number of parameters to adjust, fast optimization procedure, good generalization ability, working on the newest data without retraining, robustness to missing input variables, and generating a vector as an output. In the experimental part of the work the proposed models were used to forecasting the monthly demand for 35 European countries. The model performances were compared with the performances of the classical models such as ARIMA and exponential smoothing as well as state-of-the-art models such as multilayer perceptron, neuro-fuzzy system and long short-term memory model. The results show high performance of the proposed models which outperform the comparative models in accuracy, simplicity and ease of optimization., Comment: 17 pages, 11 figures

Published
2020

56. Classification of smooth factorial affine surfaces of Kodaira dimension zero with trivial units

Author

Pełka, Tomasz and Raźny, Paweł

Subjects
Mathematics - Algebraic Geometry, 14R05 (Primary) 14J26, 57R65, 57M99 (Secondary)
Abstract

We give a corrected statement of the theorem of Gurjar and Miyanishi, which classifies smooth affine surfaces of Kodaira dimension zero, whose coordinate ring is factorial and has trivial units. Denote the class of such surfaces by $\mathcal{S}_{0}$. An infinite series of surfaces in $\mathcal{S}_{0}$, not listed by Gurjar and Miyanishi, was recently obtained by Freudenburg, Kojima and Nagamine as affine modifications of the plane. We complete their list to a series containing arbitrarily high-dimensional families of pairwise non-isomorphic surfaces in $\mathcal{S}_{0}$. Moreover, we classify them up to a diffeomorphism, showing that each occurs as an interior of a 4-manifold whose boundary is an exceptional surgery on a 2-bridge knot. In particular, we show that $\mathcal{S}_{0}$ contains countably many pairwise non-homeomorphic surfaces., Comment: 21 pages, 16 figures

Published
2020
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57. Measuring the structure and equation of state of polyethylene terephthalate at megabar pressures.

Author

Lütgert, J, Vorberger, J, Hartley, NJ, Voigt, K, Rödel, M, Schuster, AK, Benuzzi-Mounaix, A, Brown, S, Cowan, TE, Cunningham, E, Döppner, T, Falcone, RW, Fletcher, LB, Galtier, E, Glenzer, SH, Laso Garcia, A, Gericke, DO, Heimann, PA, Lee, HJ, McBride, EE, Pelka, A, Prencipe, I, Saunders, AM, Schölmerich, M, Schörner, M, Sun, P, Vinci, T, Ravasio, A, and Kraus, D

Abstract

We present structure and equation of state (EOS) measurements of biaxially orientated polyethylene terephthalate (PET, [Formula: see text], also called mylar) shock-compressed to ([Formula: see text]) GPa and ([Formula: see text]) K using in situ X-ray diffraction, Doppler velocimetry, and optical pyrometry. Comparing to density functional theory molecular dynamics (DFT-MD) simulations, we find a highly correlated liquid at conditions differing from predictions by some equations of state tables, which underlines the influence of complex chemical interactions in this regime. EOS calculations from ab initio DFT-MD simulations and shock Hugoniot measurements of density, pressure and temperature confirm the discrepancy to these tables and present an experimentally benchmarked correction to the description of PET as an exemplary material to represent the mixture of light elements at planetary interior conditions.

Published
2021

58. Novel experimental setup for megahertz X‐ray diffraction in a diamond anvil cell at the High Energy Density (HED) instrument of the European X‐ray Free‐Electron Laser (EuXFEL)

Author

Liermann, HP, Konôpková, Z, Appel, K, Prescher, C, Schropp, A, Cerantola, V, Husband, RJ, McHardy, JD, McMahon, MI, McWilliams, RS, Pépin, CM, Mainberger, J, Roeper, M, Berghäuser, A, Damker, H, Talkovski, P, Foese, M, Kujala, N, Ball, OB, Baron, MA, Briggs, R, Bykov, M, Bykova, E, Chantel, J, Coleman, AL, Cynn, H, Dattelbaum, D, Dresselhaus-Marais, LE, Eggert, JH, Ehm, L, Evans, WJ, Fiquet, G, Frost, M, Glazyrin, K, Goncharov, AF, Hwang, H, Jenei, Zs, Kim, J-Y, Langenhorst, F, Lee, Y, Makita, M, Marquardt, H, McBride, EE, Merkel, S, Morard, G, O'Bannon, EF, Otzen, C, Pace, EJ, Pelka, A, Pigott, JS, Prakapenka, VB, Redmer, R, Sanchez-Valle, C, Schoelmerich, M, Speziale, S, Spiekermann, G, Sturtevant, BT, Toleikis, S, Velisavljevic, N, Wilke, M, Yoo, C-S, Baehtz, C, Zastrau, U, and Strohm, C

Subjects
diamond anvil cells, X-ray free-electron lasers, high-precision X-ray diffraction, finite element modeling, Condensed Matter Physics, Optical Physics, Physical Chemistry (incl. Structural), Biophysics
Abstract

The high-precision X-ray diffraction setup for work with diamond anvil cells (DACs) in interaction chamber 2 (IC2) of the High Energy Density instrument of the European X-ray Free-Electron Laser is described. This includes beamline optics, sample positioning and detector systems located in the multipurpose vacuum chamber. Concepts for pump-probe X-ray diffraction experiments in the DAC are described and their implementation demonstrated during the First User Community Assisted Commissioning experiment. X-ray heating and diffraction of Bi under pressure, obtained using 20 fs X-ray pulses at 17.8 keV and 2.2 MHz repetition, is illustrated through splitting of diffraction peaks, and interpreted employing finite element modeling of the sample chamber in the DAC.

Published
2021

59. Combined PD-1, BRAF and MEK inhibition in BRAFV600E colorectal cancer: a phase 2 trial

Author

Tian, Jun, Chen, Jonathan H., Chao, Sherry X., Pelka, Karin, Giannakis, Marios, Hess, Julian, Burke, Kelly, Jorgji, Vjola, Sindurakar, Princy, Braverman, Jonathan, Mehta, Arnav, Oka, Tomonori, Huang, Mei, Lieb, David, Spurrell, Maxwell, Allen, Jill N., Abrams, Thomas A., Clark, Jeffrey W., Enzinger, Andrea C., Enzinger, Peter C., Klempner, Samuel J., McCleary, Nadine J., Meyerhardt, Jeffrey A., Ryan, David P., Yurgelun, Matthew B., Kanter, Katie, Van Seventer, Emily E., Baiev, Islam, Chi, Gary, Jarnagin, Joy, Bradford, William B., Wong, Edmond, Michel, Alexa G., Fetter, Isobel J., Siravegna, Giulia, Gemma, Angelo J., Sharpe, Arlene, Demehri, Shadmehr, Leary, Rebecca, Campbell, Catarina D., Yilmaz, Omer, Getz, Gad A., Parikh, Aparna R., Hacohen, Nir, and Corcoran, Ryan B.

Published
2023
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60. Nanocrystalline Iron Oxides with Various Average Crystallite Size Investigated Using Magnetic Resonance Method

Author

Rafał Pelka, Urszula Nowosielecka, Kamila Klimza, Izabela Moszyńska, Konstantinos Aidinis, Grzegorz Żołnierkiewicz, Aleksander Guskos, and Nikos Guskos

Subjects
iron oxides, nanocrystallites, magnetic resonance, magnetic properties, nanocrystallite size distribution, Crystallography, QD901-999
Abstract

A series of nanocrystalline iron oxide samples (M1–M5) which differ from each other in average crystallite size (from 26 to 37 nm) was studied. The raw material was nanocrystalline iron with an average crystallite size equal to 21 nm promoted with hardly reducible oxides: Al2O3, CaO, K2O (in total, max. 10 wt%). Nanocrystalline iron was subjected to oxidation with water vapor to achieve different oxidation degrees (α = 0.16–1.00). Metallic iron remaining in the samples after the oxidizing step was removed by etching. Magnetic resonance spectra of all samples were obtained at room temperature. All resonance lines were asymmetric and intense. These spectra were fitted by Lorentzian and Gaussian functions. All spectral parameters depend on the preparation method of the nanoparticles. We suppose that the Lorentz fit gives us a spectrum from larger agglomerated sizes whereas the Gaussian fit comes from much smaller magnetic centers. For the nanocrystalline samples with the largest size of iron oxide nanocrystallites, the highest value of total integrated intensity was obtained, indicating that at smaller sizes, they are more mobile in reorientation processes resulting in more settings of anti-parallel magnetic moments. The magnetic anisotropy should also increase with the increase in size of nanocrystallites.

Published
2024
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61. Validity and Reliability of a Linear Position Transducer to Measure Velocity, Duration, and Displacement in the Barbell Back Squat

Author

Ryan Gant, Anthony Pinzone, Jennifer Rivera, Edward Pelka, Emily Tagesen, Modesto Lebron, and Adam Jajtner

Subjects
Velocity-Based Training, Autoregulation, Resistance Exercise, Sports, GV557-1198.995, Sports medicine, RC1200-1245
Abstract

The purpose of this investigation was to determine the validity and reliability of the Humac360 linear position transducer (LPT) as compared to Tendo Weightlifting Analyzer. Seventeen recreationally active men and women completed three visits. Visit one included maximal strength assessments via one-repetition maximum (1RM) for the barbell back squat. On visits two and three, participants completed two sets of three repetitions at 30-, 50-, 60-, and 70% 1RM. Mean Concentric Velocity (MCV), Peak Velocity (PV), Displacement (D), and Duration (T) were collected. Repetition data agreement was assessed with Intraclass Correlation Coefficients (ICCs) and were categorized as poor (0.90). Significance was accepted at an alpha (p) value < 0.05. Repetition-to-repetition comparisons between devices demonstrate varying degrees of agreement, with significant differences between devices across all intensities and all measurements (p < 0.001). Inter-set reliability was excellent for MCV, PV, D, and T with the exceptions of MCV and PV at 70% 1RM (ICC2,k = 0.548 and 0.816). Inter-session reliability data demonstrated reduced agreeableness in an intensity-dependent manner, with ICCs decreasing and SEMs increasing with increases in intensity. The Humac360 LPT does not appear to be valid when compared to the criterion reference, though we contend it maintains construct validity. Coaches may use the Humac360 LPT as a tool to monitor fatigue, and the associated changes in trainee movement velocity on an inter-set and inter-session basis.

Published
2023
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62. Chimera states in small disordered optomechanical arrays

Author

Pelka, Karl, Peano, Vittorio, and Xuereb, André

Subjects
Quantum Physics, Condensed Matter - Disordered Systems and Neural Networks
Abstract

Synchronization of weakly-coupled non-linear oscillators is a ubiquitous phenomenon that has been observed across the natural sciences. We study the dynamics of optomechanical arrays - networks of mechanically compliant structures that interact with the radiation pressure force - which are driven to self-oscillation. These systems offer a convenient platform to study synchronization phenomena and have potential technological applications. We demonstrate that this system supports the existence of long-lived chimera states, where parts of the array synchronize whilst others do not. Through a combined numerical and analytical analysis we show that these chimera states can only emerge in the presence of disorder., Comment: 4+ pages, 4 figures, comments very welcome!

Published
2019
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63. Thermodynamics of Iron Ammonia Synthesis Catalyst Sintering

Author

Walerian Arabczyk, Rafał Pelka, Izabella Jasińska, and Zofia Lendzion-Bieluń

Subjects
nanocrystalline iron, sintering, iron ammonia synthesis catalyst, thermodynamics, Crystallography, QD901-999
Abstract

The sintering of iron ammonia synthesis catalysts (nanocrystalline iron promoted with: Al2O3, CaO and K2O) was studied under a hydrogen atmosphere, in a temperature range of 773 to 973 K to obtain stationary states. The catalysts were characterized by measuring the nitriding reaction rate under an ammonia atmosphere at 748 K to obtain steady states and the measurement of specific surface area. Chemical processes were conducted in a tubular differential reactor enabling thermogravimetric measurements and the chemical composition analysis of a gas phase under conditions allowing experiments to be carried out in the kinetic region of chemical reactions. An extended model of the active surface of the iron ammonia synthesis catalyst was presented, taking into account the influence of the gas phase composition and process temperature. The surface of iron nanocrystallites was wetted using promoters in an exothermic process associated with the formation of the surface Fes-O- bond and the change in the surface energy of iron nanocrystallites. Promoters formed on the surface of iron nanocrystallites with different structures of chemisorbed dipoles, depending on the composition of the gas phase. The occupied sites stabilized the structure, and the free sites were active sites in the process of adsorption of chemical reagents and in sintering. Based on the bonding energy of the promoter oxides and the difference in surface energy between the covered and uncovered surfaces, the wetting abilities of promoters, which can be arranged according to the order K2O > Fe3O4 > Al2O3 > CaO, were estimated. By increasing the temperature in the endothermic sintering process, the degree of surface coverage with dipoles of promoters decreased, and thus the catalyst underwent sintering. The size distribution of nanocrystallites did not change with decreasing temperature. Only the equilibrium between the glass phase and the surface of iron nanocrystallites was then established.

Published
2024
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64. Experimental research on the TCV tokamak

Author

B.P. Duval, A. Abdolmaleki, M. Agostini, C.J. Ajay, S. Alberti, E. Alessi, G. Anastasiou, Y. Andrèbe, G.M. Apruzzese, F. Auriemma, J. Ayllon-Guerola, F. Bagnato, A. Baillod, F. Bairaktaris, L. Balbinot, A. Balestri, M. Baquero-Ruiz, C. Barcellona, M. Bernert, W. Bin, P. Blanchard, J. Boedo, T. Bolzonella, F. Bombarda, L. Boncagni, M. Bonotto, T.O.S.J. Bosman, D. Brida, D. Brunetti, J. Buchli, J. Buerman, P. Buratti, A. Burckhart, D. Busil, J. Caloud, Y. Camenen, A. Cardinali, S. Carli, D. Carnevale, F. Carpanese, M. Carpita, C. Castaldo, F. Causa, J. Cavalier, M. Cavedon, J.A. Cazabonne, J. Cerovsky, B. Chapman, M. Chernyshova, P. Chmielewski, A. Chomiczewska, G. Ciraolo, S. Coda, C. Colandrea, C. Contré, R. Coosemans, L. Cordaro, S. Costea, T. Craciunescu, K. Crombe, A. Dal Molin, O. D’Arcangelo, D. de Las Casas, J. Decker, J. Degrave, H. de Oliveira, G.L. Derks, L.E. di Grazia, C. Donner, M. Dreval, M.G. Dunne, G. Durr-Legoupil-Nicoud, B. Esposito, T. Ewalds, M. Faitsch, M. Farník, A. Fasoli, F. Felici, J. Ferreira, O. Février, O. Ficker, A. Frank, E. Fransson, L. Frassinetti, L. Fritz, I. Furno, D. Galassi, K. Gałązka, J. Galdon-Quiroga, S. Galeani, C. Galperti, S. Garavaglia, M. Garcia-Munoz, P. Gaudio, M. Gelfusa, J. Genoud, R. Gerrú Miguelanez, G. Ghillardi, M. Giacomin, L. Gil, A. Gillgren, C. Giroud, T. Golfinopoulos, T. Goodman, G. Gorini, S. Gorno, G. Grenfell, M. Griener, M. Gruca, T. Gyergyek, R. Hafner, M. Hamed, D. Hamm, W. Han, G. Harrer, J.R. Harrison, D. Hassabis, S. Henderson, P. Hennequin, J. Hidalgo-Salaverri, J-P. Hogge, M. Hoppe, J. Horacek, A. Huber, E. Huett, A. Iantchenko, P. Innocente, C. Ionita-Schrittwieser, I. Ivanova Stanik, M. Jablczynska, A. Jansen van Vuuren, A. Jardin, H. Järleblad, A.E. Järvinen, J. Kalis, R. Karimov, A.N. Karpushov, K. Kavukcuoglu, J. Kay, Y. Kazakov, J. Keeling, A. Kirjasuo, J.T.W. Koenders, P. Kohli, M. Komm, M. Kong, J. Kovacic, E. Kowalska-Strzeciwilk, O. Krutkin, O. Kudlacek, U. Kumar, R. Kwiatkowski, B. Labit, L. Laguardia, E. Laszynska, A. Lazaros, K. Lee, E. Lerche, B. Linehan, D. Liuzza, T. Lunt, E. Macusova, D. Mancini, P. Mantica, M. Maraschek, G. Marceca, S. Marchioni, A. Mariani, M. Marin, A. Marinoni, L. Martellucci, Y. Martin, P. Martin, L. Martinelli, F. Martinelli, J.R. Martin-Solis, S. Masillo, R. Masocco, V. Masson, A. Mathews, M. Mattei, D. Mazon, S. Mazzi, S.Y. Medvedev, C. Meineri, A. Mele, V. Menkovski, A. Merle, H. Meyer, K. Mikszuta-Michalik, I.G. Miron, P.A. Molina Cabrera, A. Moro, A. Murari, P. Muscente, D. Mykytchuk, F. Nabais, F. Napoli, R.D. Nem, M. Neunert, S.K. Nielsen, A. Nielsen, M. Nocente, S. Noury, S. Nowak, H. Nyström, N. Offeddu, S. Olasz, F. Oliva, D.S. Oliveira, F.P. Orsitto, N. Osborne, P. Oyola Dominguez, O. Pan, E. Panontin, A.D. Papadopoulos, P. Papagiannis, G. Papp, M. Passoni, F. Pastore, A. Pau, R.O. Pavlichenko, A.C. Pedersen, M. Pedrini, G. Pelka, E. Peluso, A. Perek, C. Perez Von Thun, F. Pesamosca, D. Pfau, V. Piergotti, L. Pigatto, C. Piron, L. Piron, A. Pironti, U. Plank, V. Plyusnin, Y.R.J. Poels, G.I. Pokol, J. Poley-Sanjuan, M. Poradzinski, L. Porte, C. Possieri, A. Poulsen, M.J. Pueschel, T. Pütterich, V. Quadri, M. Rabinski, R. Ragona, H. Raj, A. Redl, H. Reimerdes, C. Reux, D. Ricci, M. Riedmiller, S. Rienäcker, D. Rigamonti, N. Rispoli, J.F. Rivero-Rodriguez, C.F. Romero Madrid, J. Rueda Rueda, P.J. Ryan, M. Salewski, A. Salmi, M. Sassano, O. Sauter, N. Schoonheere, R.W. Schrittwieser, F. Sciortino, A. Selce, L. Senni, S. Sharapov, U.A. Sheikh, B. Sieglin, M. Silva, D. Silvagni, B. Simmendefeldt Schmidt, L. Simons, E.R. Solano, C. Sozzi, M. Spolaore, L. Spolladore, A. Stagni, P. Strand, G. Sun, W. Suttrop, J. Svoboda, B. Tal, T. Tala, P. Tamain, M. Tardocchi, A. Tema Biwole, A. Tenaglia, D. Terranova, D. Testa, C. Theiler, A. Thornton, A.S. Thrysoe, M. Tomes, E. Tonello, H. Torreblanca, B. Tracey, M. Tsimpoukelli, C. Tsironis, C.K. Tsui, M. Ugoletti, M. Vallar, M. van Berkel, S. van Mulders, M. van Rossem, C. Venturini, M. Veranda, T. Verdier, K. Verhaegh, L. Vermare, N. Vianello, E. Viezzer, F. Villone, B. Vincent, P. Vincenzi, I. Voitsekhovitch, L. Votta, N.M.T. Vu, Y. Wang, E. Wang, T. Wauters, M. Weiland, H. Weisen, N. Wendler, S. Wiesen, M. Wiesenberger, T. Wijkamp, C. Wüthrich, D. Yadykin, H. Yang, V. Yanovskiy, J. Zebrowski, P. Zestanakis, M. Zuin, and M. Zurita

Subjects
TCV, review, plasma, SPC, EPFL, Nuclear and particle physics. Atomic energy. Radioactivity, QC770-798
Abstract

Tokamak à configuration variable (TCV), recently celebrating 30 years of near-continual operation, continues in its missions to advance outstanding key physics and operational scenario issues for ITER and the design of future power plants such as DEMO. The main machine heating systems and operational changes are first described. Then follow five sections: plasma scenarios. ITER Base-Line (IBL) discharges, triangularity studies together with X3 heating and N2 seeding. Edge localised mode suppression, with a high radiation region near the X-point is reported with N _2 injection with and without divertor baffles in a snowflake configuration. Negative triangularity (NT) discharges attained record, albeit transient, β _N ∼ 3 with lower turbulence, higher low-Z impurity transport, vertical stability and density limits and core transport better than the IBL. Positive triangularity L-Mode linear and saturated ohmic confinement confinement saturation, often-correlated with intrinsic toroidal rotation reversals, was probed for D, H and He working gases. H-mode confinement and pedestal studies were extended to low collisionality with electron cyclotron heating obtaining steady state electron iternal transport barrier with neutral beam heating (NBH), and NBH driven H-mode configurations with off-axis co-electron cyclotron current drive. Fast particle physics. The physics of disruptions, runaway electrons and fast ions (FIs) was developed using near-full current conversion at disruption with recombination thresholds characterised for impurity species (Ne, Ar, Kr). Different flushing gases (D2, H2) and pathways to trigger a benign disruption were explored. The 55 kV NBH II generated a rich Alfvénic spectrum modulating the FI fas ion loss detector signal. NT configurations showed less toroidal Alfvén excitation activity preferentially affecting higher FI pitch angles. Scrape-off layer and edge physics. gas puff imaging systems characterised turbulent plasma ejection for several advanced divertor configurations, including NT. Combined diagnostic array divertor state analysis in detachment conditions was compared to modelling revealing an importance for molecular processes. Divertor physics. Internal gas baffles diversified to include shorter/longer structures on the high and/or low field side to probe compressive efficiency. Divertor studies concentrated upon mitigating target power, facilitating detachment and increasing the radiated power fraction employing alternative divertor geometries, optimised X-point radiator regimes and long-legged configurations. Smaller-than-expected improvements with total flux expansion were better modelled when including parallel flows. Peak outer target heat flux reduction was achieved (>50%) for high flux-expansion geometries, maintaining core performance ( H _98 > 1). A reduction in target heat loads and facilitated detachment access at lower core densities is reported. Real-time control. TCV’s real-time control upgrades employed MIMO gas injector control of stable, robust, partial detachment and plasma β feedback control avoiding neoclassical tearing modes with plasma confinement changes. Machine-learning enhancements include trajectory tracking disruption proximity and avoidance as well as a first-of-its-kind reinforcement learning-based controller for the plasma equilibrium trained entirely on a free-boundary simulator. Finally, a short description of TCV’s immediate future plans will be given.

Published
2024
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65. Overview of the EUROfusion Tokamak Exploitation programme in support of ITER and DEMO

Author

E. Joffrin, M. Wischmeier, M. Baruzzo, A. Hakola, A. Kappatou, D. Keeling, B. Labit, E. Tsitrone, N. Vianello, the ASDEX Upgrade Team, JET Contributors, the MAST-U Team, the TCV Team, the WEST Team, the EUROfusion Tokamak Exploitation Team:, D. Abate, J. Adamek, M. Agostini, C. Albert, F.C.P. Albert Devasagayam, S. Aleiferis, E. Alessi, J. Alhage, S. Allan, J. Allcock, M. Alonzo, G. Anastasiou, E. Andersson Sunden, C. Angioni, Y. Anquetin, L. Appel, G.M. Apruzzese, M. Ariola, C. Arnas, J.F. Artaud, W. Arter, O. Asztalos, L. Aucone, M.H. Aumeunier, F. Auriemma, J. Ayllon, E. Aymerich, A. Baciero, F. Bagnato, L. Bähner, F. Bairaktaris, P. Balázs, L. Balbinot, I. Balboa, M. Balden, A. Balestri, M. Baquero Ruiz, T. Barberis, C. Barcellona, O. Bardsley, S. Benkadda, T. Bensadon, E. Bernard, M. Bernert, H. Betar, R. Bianchetti Morales, J. Bielecki, R. Bilato, P. Bilkova, W. Bin, G. Birkenmeier, R. Bisson, P. Blanchard, A. Bleasdale, V. Bobkov, A. Boboc, A. Bock, K. Bogar, P. Bohm, T. Bolzonella, F. Bombarda, N. Bonanomi, L. Boncagni, D. Bonfiglio, R. Bonifetto, M. Bonotto, D. Borodin, I. Borodkina, T.O.S.J. Bosman, C. Bourdelle, C. Bowman, S. Brezinsek, D. Brida, F. Brochard, R. Brunet, D. Brunetti, V. Bruno, R. Buchholz, J. Buermans, H. Bufferand, P. Buratti, A. Burckhart, J. Cai, R. Calado, J. Caloud, S. Cancelli, F. Cani, B. Cannas, M. Cappelli, S. Carcangiu, A. Cardinali, S. Carli, D. Carnevale, M. Carole, M. Carpita, D. Carralero, F. Caruggi, I.S. Carvalho, I. Casiraghi, A. Casolari, F.J. Casson, C. Castaldo, A. Cathey, F. Causa, J. Cavalier, M. Cavedon, J. Cazabonne, M. Cecconello, L. Ceelen, A. Celora, J. Cerovsky, C.D. Challis, R. Chandra, A. Chankin, B. Chapman, H. Chen, M. Chernyshova, A.G. Chiariello, P. Chmielewski, A. Chomiczewska, C. Cianfarani, G. Ciraolo, J. Citrin, F. Clairet, S. Coda, R. Coelho, J.W. Coenen, I.H. Coffey, C. Colandrea, L. Colas, S. Conroy, C. Contre, N.J. Conway, L. Cordaro, Y. Corre, D. Costa, S. Costea, D. Coster, X. Courtois, C. Cowley, T. Craciunescu, G. Croci, A.M. Croitoru, K. Crombe, D.J. Cruz Zabala, G. Cseh, T. Czarski, A. Da Ros, A. Dal Molin, M. Dalla Rosa, Y. Damizia, O. D’Arcangelo, P. David, M. De Angeli, E. De la Cal, E. De La Luna, G. De Tommasi, J. Decker, R. Dejarnac, D. Del Sarto, G. Derks, C. Desgranges, P. Devynck, S. Di Genova, L.E. di Grazia, A. Di Siena, M. Dicorato, M. Diez, M. Dimitrova, T. Dittmar, L. Dittrich, J.J. Domínguez Palacios Durán, P. Donnel, D. Douai, S. Dowson, S. Doyle, M. Dreval, P. Drews, L. Dubus, R. Dumont, D. Dunai, M. Dunne, A. Durif, F. Durodie, G. Durr Legoupil Nicoud, B. Duval, R. Dux, T. Eich, A. Ekedahl, S. Elmore, G. Ericsson, J. Eriksson, B. Eriksson, F. Eriksson, S. Ertmer, A. Escarguel, B. Esposito, T. Estrada, E. Fable, M. Faitsch, N. Fakhrayi Mofrad, A. Fanni, T. Farley, M. Farník, N. Fedorczak, F. Felici, X. Feng, J. Ferreira, D. Ferreira, N. Ferron, O. Fevrier, O. Ficker, A.R. Field, A. Figueiredo, N. Fil, D. Fiorucci, M. Firdaouss, R. Fischer, M. Fitzgerald, M. Flebbe, M. Fontana, J. Fontdecaba Climent, A. Frank, E. Fransson, L. Frassinetti, D. Frigione, S. Futatani, R. Futtersack, S. Gabriellini, D. Gadariya, D. Galassi, K. Galazka, J. Galdon, S. Galeani, D. Gallart, A. Gallo, C. Galperti, M. Gambrioli, S. Garavaglia, J. Garcia, M. Garcia Munoz, J. Gardarein, L. Garzotti, J. Gaspar, R. Gatto, P. Gaudio, M. Gelfusa, J. Gerardin, S.N. Gerasimov, R. Gerru Miguelanez, G. Gervasini, Z. Ghani, F.M. Ghezzi, G. Ghillardi, L. Giannone, S. Gibson, L. Gil, A. Gillgren, E. Giovannozzi, C. Giroud, G. Giruzzi, T. Gleiter, M. Gobbin, V. Goloborodko, A. González Ganzábal, T. Goodman, V. Gopakumar, G. Gorini, T. Görler, S. Gorno, G. Granucci, D. Greenhouse, G. Grenfell, M. Griener, W. Gromelski, M. Groth, O. Grover, M. Gruca, A. Gude, C. Guillemaut, R. Guirlet, J. Gunn, T. Gyergyek, L. Hagg, J. Hall, C.J. Ham, M. Hamed, T. Happel, G. Harrer, J. Harrison, D. Harting, N.C. Hawkes, P. Heinrich, S. Henderson, P. Hennequin, R. Henriques, S. Heuraux, J. Hidalgo Salaverri, J. Hillairet, J.C. Hillesheim, A. Hjalmarsson, A. Ho, J. Hobirk, E. Hodille, M. Hölzl, M. Hoppe, J. Horacek, N. Horsten, L. Horvath, M. Houry, K. Hromasova, J. Huang, Z. Huang, A. Huber, E. Huett, P. Huynh, A. Iantchenko, M. Imrisek, P. Innocente, C. Ionita Schrittwieser, H. Isliker, P. Ivanova, I. Ivanova Stanik, M. Jablczynska, S. Jachmich, A.S. Jacobsen, P. Jacquet, A. Jansen van Vuuren, A. Jardin, H. Järleblad, A. Järvinen, F. Jaulmes, T. Jensen, I. Jepu, S. Jessica, T. Johnson, A. Juven, J. Kalis, J. Karhunen, R. Karimov, A.N. Karpushov, S. Kasilov, Y. Kazakov, P.V. Kazantzidis, W. Kernbichler, HT. Kim, D.B. King, V.G. Kiptily, A. Kirjasuo, K.K. Kirov, A. Kirschner, A. Kit, T. Kiviniemi, F. Kjær, E. Klinkby, A. Knieps, U. Knoche, M. Kochan, F. Köchl, G. Kocsis, J.T.W. Koenders, L. Kogan, Y. Kolesnichenko, Y. Kominis, M. Komm, M. Kong, B. Kool, S.B. Korsholm, D. Kos, M. Koubiti, J. Kovacic, Y. Kovtun, E. Kowalska Strzeciwilk, K. Koziol, M. Kozulia, A. Krämer Flecken, A. Kreter, K. Krieger, U. Kruezi, O. Krutkin, O. Kudlacek, U. Kumar, H. Kumpulainen, M.H. Kushoro, R. Kwiatkowski, M. La Matina, M. Lacquaniti, L. Laguardia, P. Lainer, P. Lang, M. Larsen, E. Laszynska, K.D. Lawson, A. Lazaros, E. Lazzaro, M.Y.K. Lee, S. Leerink, M. Lehnen, M. Lennholm, E. Lerche, Y. Liang, A. Lier, J. Likonen, O. Linder, B. Lipschultz, A. Listopad, X. Litaudon, E. Litherland Smith, D. Liuzza, T. Loarer, P.J. Lomas, J. Lombardo, N. Lonigro, R. Lorenzini, C. Lowry, T. Luda di Cortemiglia, A. Ludvig Osipov, T. Lunt, V. Lutsenko, E. Macusova, R. Mäenpää, P. Maget, C.F. Maggi, J. Mailloux, S. Makarov, K. Malinowski, P. Manas, A. Mancini, D. Mancini, P. Mantica, M. Mantsinen, J. Manyer, M. Maraschek, G. Marceca, G. Marcer, C. Marchetto, S. Marchioni, A. Mariani, M. Marin, M. Markl, T. Markovic, D. Marocco, S. Marsden, L. Martellucci, P. Martin, C. Martin, F. Martinelli, L. Martinelli, J.R. Martin Solis, R. Martone, M. Maslov, R. Masocco, M. Mattei, G.F. Matthews, D. Matveev, E. Matveeva, M.L. Mayoral, D. Mazon, S. Mazzi, C. Mazzotta, G. McArdle, R. McDermott, K. McKay, A.G. Meigs, C. Meineri, A. Mele, V. Menkovski, S. Menmuir, A. Merle, H. Meyer, K. Mikszuta Michalik, D. Milanesio, F. Militello, A. Milocco, I.G. Miron, J. Mitchell, R. Mitteau, V. Mitterauer, J. Mlynar, V. Moiseenko, P. Molna, F. Mombelli, C. Monti, A. Montisci, J. Morales, P. Moreau, J.M. Moret, A. Moro, D. Moulton, P. Mulholland, M. Muraglia, A. Murari, A. Muraro, P. Muscente, D. Mykytchuk, F. Nabais, Y. Nakeva, F. Napoli, E. Nardon, M.F. Nave, R.D. Nem, A. Nielsen, S.K. Nielsen, M. Nocente, R. Nouailletas, S. Nowak, H. Nyström, R. Ochoukov, N. Offeddu, S. Olasz, C. Olde, F. Oliva, D. Oliveira, H.J.C. Oliver, P. Ollus, J. Ongena, F.P. Orsitto, N. Osborne, R. Otin, P. Oyola Dominguez, D.I. Palade, S. Palomba, O. Pan, N. Panadero, E. Panontin, A. Papadopoulos, P. Papagiannis, G. Papp, V.V. Parail, C. Pardanaud, J. Parisi, A. Parrott, K. Paschalidis, M. Passoni, F. Pastore, A. Patel, B. Patel, A. Pau, G. Pautasso, R. Pavlichenko, E. Pawelec, B. Pegourie, G. Pelka, E. Peluso, A. Perek, E. Perelli Cippo, C. Perez Von Thun, P. Petersson, G. Petravich, Y. Peysson, V. Piergotti, L. Pigatto, C. Piron, L. Piron, A. Pironti, F. Pisano, U. Plank, B. Ploeckl, V. Plyusnin, A. Podolnik, Y. Poels, G. Pokol, J. Poley, G. Por, M. Poradzinski, F. Porcelli, L. Porte, C. Possieri, A. Poulsen, I. Predebon, G. Pucella, M. Pueschel, P. Puglia, O. Putignano, T. Pütterich, V. Quadri, A. Quercia, M. Rabinski, L. Radovanovic, R. Ragona, H. Raj, M. Rasinski, J. Rasmussen, G. Ratta, S. Ratynskaia, R. Rayaprolu, M. Rebai, A. Redl, D. Rees, D. Refy, M. Reich, H. Reimerdes, B.C.G. Reman, O. Renders, C. Reux, D. Ricci, M. Richou, S. Rienacker, D. Rigamonti, F. Rigollet, F.G. Rimini, D. Ripamonti, N. Rispoli, N. Rivals, J.F. Rivero Rodriguez, C. Roach, G. Rocchi, S. Rode, P. Rodrigues, J. Romazanov, C.F. Romero Madrid, J. Rosato, R. Rossi, G. Rubino, J. Rueda Rueda, J. Ruiz Ruiz, P. Ryan, D. Ryan, S. Saarelma, R. Sabot, M. Salewski, A. Salmi, L. Sanchis, A. Sand, J. Santos, K. Särkimäki, M. Sassano, O. Sauter, G. Schettini, S. Schmuck, P. Schneider, N. Schoonheere, R. Schramm, R. Schrittwieser, C. Schuster, N. Schwarz, F. Sciortino, M. Scotto D’Abusco, S. Scully, A. Selce, L. Senni, M. Senstius, G. Sergienko, S.E. Sharapov, R. Sharma, A. Shaw, U. Sheikh, G. Sias, B. Sieglin, S.A. Silburn, C. Silva, A. Silva, D. Silvagni, B. Simmendefeldt Schmidt, L. Simons, J. Simpson, L. Singh, S. Sipilä, Y. Siusko, S. Smith, A. Snicker, E.R. Solano, V. Solokha, M. Sos, C. Sozzi, F. Spineanu, G. Spizzo, M. Spolaore, L. Spolladore, C. Srinivasan, A. Stagni, Z. Stancar, G. Stankunas, J. Stober, P. Strand, C.I. Stuart, F. Subba, G.Y. Sun, H.J. Sun, W. Suttrop, J. Svoboda, T. Szepesi, G. Szepesi, B. Tal, T. Tala, P. Tamain, G. Tardini, M. Tardocchi, D. Taylor, G. Telesca, A. Tenaglia, A. Terra, D. Terranova, D. Testa, C. Theiler, E. Tholerus, B. Thomas, E. Thoren, A. Thornton, A. Thrysoe, Q. TICHIT, W. Tierens, A. Titarenko, P. Tolias, E. Tomasina, M. Tomes, E. Tonello, A. Tookey, M. Toscano Jiménez, C. Tsironis, C. Tsui, A. Tykhyy, M. Ugoletti, M. Usoltseva, D.F. Valcarcel, A. Valentini, M. Valisa, M. Vallar, M. Valovic, SI. Valvis, M. van Berkel, D. Van Eester, S. Van Mulders, M. van Rossem, R. Vann, B. Vanovac, J. Varela Rodriguez, J. Varje, S. Vartanian, M. Vecsei, L. Velarde Gallardo, M. Veranda, T. Verdier, G. Verdoolaege, K. Verhaegh, L. Vermare, G. Verona Rinati, J. Vicente, E. Viezzer, L. Vignitchouk, F. Villone, B. Vincent, P. Vincenzi, M.O. Vlad, G. Vogel, I. Voitsekhovitch, I. Voldiner, P. Vondracek, N.M.T. VU, T. Vuoriheimo, C. Wade, E. Wang, T. Wauters, M. Weiland, H. Weisen, N. Wendler, D. Weston, A. Widdowson, S. Wiesen, M. Wiesenberger, T. Wijkamp, M. Willensdorfer, T. Wilson, A. Wojenski, C. Wuethrich, I. Wyss, L. Xiang, S. Xu, D. Yadykin, Y. Yakovenko, H. Yang, V. Yanovskiy, R. Yi, B. Zaar, G. Zadvitskiy, L. Zakharov, P. Zanca, D. Zarzoso, Y. Zayachuk, J. Zebrowski, M. Zerbini, P. Zestanakis, C. F. B. Zimmermann, M. Zlobinski, A. Zohar, V.K. Zotta, X. Zou, M. Zuin, M. Zurita, and I. Zychor

Subjects
JET, ASDEX Upgrade, MAST-U, TCV, WEST, Tokamak Exploitation Task Force, Nuclear and particle physics. Atomic energy. Radioactivity, QC770-798
Abstract

Within the 9th European Framework programme, since 2021 EUROfusion is operating five tokamaks under the auspices of a single Task Force called ‘Tokamak Exploitation’. The goal is to benefit from the complementary capabilities of each machine in a coordinated way and help in developing a scientific output scalable to future largre machines. The programme of this Task Force ensures that ASDEX Upgrade, MAST-U, TCV, WEST and JET (since 2022) work together to achieve the objectives of Missions 1 and 2 of the EUROfusion Roadmap: i) demonstrate plasma scenarios that increase the success margin of ITER and satisfy the requirements of DEMO and, ii) demonstrate an integrated approach that can handle the large power leaving ITER and DEMO plasmas. The Tokamak Exploitation task force has therefore organized experiments on these two missions with the goal to strengthen the physics and operational basis for the ITER baseline scenario and for exploiting the recent plasma exhaust enhancements in all four devices (PEX: Plasma EXhaust) for exploring the solution for handling heat and particle exhaust in ITER and develop the conceptual solutions for DEMO. The ITER Baseline scenario has been developed in a similar way in ASDEX Upgrade, TCV and JET. Key risks for ITER such as disruptions and run-aways have been also investigated in TCV, ASDEX Upgrade and JET. Experiments have explored successfully different divertor configurations (standard, super-X, snowflakes) in MAST-U and TCV and studied tungsten melting in WEST and ASDEX Upgrade. The input from the smaller devices to JET has also been proven successful to set-up novel control schemes on disruption avoidance and detachment.

Published
2024
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66. Kinetics and Thermodynamics of the Phase Transformation in the Nanocrystalline Substance—Gas Phase System

Author

Walerian Arabczyk, Rafał Pelka, Bartłomiej Wilk, and Zofia Lendzion-Bieluń

Subjects
chemical reaction model, diffusion, phase transformation, thermodynamics, kinetics, Crystallography, QD901-999
Abstract

This study presents a model of the reaction of a nanocrystalline substance within the gas phase, where diffusion of gas reactants in the volume of the nanocrystallites is a rate-limiting step. According to the model calculations carried out, the rate of diffusion across the phase boundary located on the nanocrystallite surface limits the rate of the process. It was stated that in chemical processes with a phase transformation, the critical concentration of absorbate depends on two factors: the specific active surface area of the adsorbent and the difference in chemical potentials between the gas phase and the equilibrium potential at which the phase transformation occurs. When the actual adsorbate potential in the gas phase is much greater than the equilibrium potential of the nanocrystallite with the largest specific active surface, nanocrystallites undergo phase changes in the order according to their specific active surfaces from the largest to the smallest. In a process where the actual adsorbate potential is close to an equilibrium one, nanocrystallites undergo phase transformation in the order of their specific active surface from the smallest to the largest.

Published
2024
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68. Classification of planar rational cuspidal curves. II. Log del Pezzo models

Author

Palka, Karol and Pełka, Tomasz

Subjects
Mathematics - Algebraic Geometry, Mathematics - Complex Variables, 14H50, 14J17, 14R25
Abstract

Let $E\subseteq \mathbb{P}^2$ be a complex curve homeomorphic to the projective line. The Negativity Conjecture asserts that the Kodaira-Iitaka dimension of $K_X+\frac{1}{2}D$, where $(X,D)\to (\mathbb{P}^{2},E)$ is a minimal log resolution, is negative. We prove structure theorems for curves satisfying this conjecture and we finish their classification up to a projective equivalence by describing the ones whose complement admits no $\mathbb{C}^{**}$-fibration. As a consequence, we show that they satisfy the Strong Rigidity Conjecture of Flenner-Zaidenberg. The proofs are based on the almost minimal model program. The obtained list contains one new series of bicuspidal curves., Comment: 50 pages

Published
2018
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69. Prime Number Decomposition using the Talbot Effect

Author

Pelka, Karl, Graf, Jasmin, Mehringer, Thomas, and von Zanthier, Joachim

Subjects
Physics - Optics
Abstract

We report on prime number decomposition by use of the Talbot effect, a well-known phenomenon in classical near field optics whose description is closely related to Gauss sums. The latter are a mathematical tool from number theory used to analyze the properties of prime numbers as well as to decompose composite numbers into their prime factors. We employ the well-established connection between the Talbot effect and Gauss sums to implement prime number decompositions with a novel approach, making use of the longitudinal intensity profile of the Talbot carpet. The new algorithm is experimentally verified and the limits of the approach are discussed., Comment: - 6 pages, 3 figures - 6 pages, 3 figures, added references in the introduction

Published
2018
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70. Observation of ultrafast solid-density plasma dynamics using femtosecond X-ray pulses from a free-electron laser

Author

Kluge, Thomas, Rödel, Melanie, Metzkes, Josefine, Pelka, Alexander, Garcia, Alejandro Laso, Prencipe, Irene, Rehwald, Martin, Nakatsutsumi, Motoaki, McBride, Emma E., Schönherr, Tommy, Garten, Marco, Hartley, Nicholas J., Zacharias, Malte, Erbe, Arthur, Georgiev, Yordan M., Galtier, Eric, Nam, Inhyuk, Lee, Hae Ja, Glenzer, Siegfried, Bussmann, Michael, Gutt, Christian, Zeil, Karl, Rödel, Christian, Hübner, Uwe, Schramm, Ulrich, and Cowan, Thomas E.

Subjects
Physics - Plasma Physics
Abstract

The complex physics of the interaction between short pulse high intensity lasers and solids is so far hardly accessible by experiments. As a result of missing experimental capabilities to probe the complex electron dynamics and competing instabilities, this impedes the development of compact laser-based next generation secondary radiation sources, e.g. for tumor therapy [Bulanov2002,ledingham2007], laboratory-astrophysics [Remington1999,Bulanov2015], and fusion [Tabak2014]. At present, the fundamental plasma dynamics that occur at the nanometer and femtosecond scales during the laser-solid interaction can only be elucidated by simulations. Here we show experimentally that small angle X-ray scattering of femtosecond X-ray free-electron laser pulses facilitates new capabilities for direct in-situ characterization of intense short-pulse laser plasma interaction at solid density that allows simultaneous nanometer spatial and femtosecond temporal resolution, directly verifying numerical simulations of the electron density dynamics during the short pulse high intensity laser irradiation of a solid density target. For laser-driven grating targets, we measure the solid density plasma expansion and observe the generation of a transient grating structure in front of the pre-inscribed grating, due to plasma expansion, which is an hitherto unknown effect. We expect that our results will pave the way for novel time-resolved studies, guiding the development of future laser-driven particle and photon sources from solid targets.

Published
2018
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72. High-pressure chemistry of hydrocarbons relevant to planetary interiors and inertial confinement fusion

Author

Kraus, D., Hartley, N. J, Frydrych, S., Schuster, A. K, Rohatsch, K., Rödel, M., Cowan, T. E, Brown, S., Cunningham, E., van Driel, T., Fletcher, L. B, Galtier, E., Gamboa, E. J, Laso Garcia, A., Gericke, D. O, Granados, E., Heimann, P. A, Lee, H. J, MacDonald, M. J, MacKinnon, A. J, McBride, E. E, Nam, I., Neumayer, P., Pak, A., Pelka, A., Prencipe, I., Ravasio, A., Redmer, R., Saunders, A. M, Schölmerich, M., Schörner, M., Sun, P., Turner, S. J, Zettl, A., Falcone, R. W, Glenzer, S. H, T. Döppner, T., and Vorberger, J.

Published
2018

73. Magnetism of a sigma-phase Fe60V40 alloy: magnetic susceptibilities and magnetocaloric effect studies

Author

Balanda, M., Dubiel, S. M., and Pelka, R.

Subjects
Condensed Matter - Strongly Correlated Electrons
Abstract

Magnetic properties of a sigma-phase Fe60V40 intermetallic compound were studied by means of ac and dc magnetic susceptibility and magnetocaloric effect measurements. The compound is a soft magnet yet it was found to behave like a re-entrant spin-glass system. The magnetic ordering temperature was found to be T_C ca.170 K, while the spin-freezing temperature was ca.164 K. Its relative shift per decade of ac frequency was 0.002, a value smaller than that typical of canonical spin-glasses. Magnetic entropy change, DeltaS, in the vicinity of T_C was determined for magnetic field, H, ranging between 5 and 50 kOe. Analysis of DeltaS in terms of the power law yielded the critical exponent, n, vs. temperature with the minimum value of 0.75 at T_C, while from the analysis of a relative shift of the maximum value of DeltaS with the field a critical exponent Delta=1.7 was obtained. Based on scaling laws relationships values of other two exponents viz. betha=0.6 and gamma=1 were determined., Comment: 12 pages, 18 figures, 24 references

Published
2016
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74. Classification of planar rational cuspidal curves. I. C**-fibrations

Author

Palka, Karol and Pełka, Tomasz

Subjects
Mathematics - Algebraic Geometry, 14H50, 14J17, 14R25
Abstract

To classify complex rational cuspidal curves $E\subseteq \mathbb{P}^2$ it remains to classify the ones with complement of log general type, i.e. the ones for which $\kappa(K_X+D)=2$, where $(X,D)$ is a log resolution of $(\mathbb{P}^2,E)$. It is conjectured that $\kappa(K_X+\frac{1}{2}D)=-\infty$ and hence $\mathbb{P}^2\setminus E$ is $\mathbb{C}^{**}$-fibered, where $\mathbb{C}^{**}=\mathbb{C}^1\setminus\{0,1\}$, or $-(K_X+\frac{1}{2}D)$ is ample on some minimal model of $(X,\frac{1}{2}D)$. Here we classify, up to a projective equivalence, those rational cuspidal curves for which the complement is $\mathbb{C}^{**}$-fibered. From the rich list of known examples only very few are not of this type. We also discover a new infinite family of bicuspidal curves with unusual properties., Comment: 50 pages

Published
2016
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76. Electron-Ion Temperature Relaxation in Warm Dense Hydrogen Observed With Picosecond Resolved X-Ray Scattering

Author

L. B. Fletcher, J. Vorberger, W. Schumaker, C. Ruyer, S. Goede, E. Galtier, U. Zastrau, E. P. Alves, S. D. Baalrud, R. A. Baggott, B. Barbrel, Z. Chen, T. Döppner, M. Gauthier, E. Granados, J. B. Kim, D. Kraus, H. J. Lee, M. J. MacDonald, R. Mishra, A. Pelka, A. Ravasio, C. Roedel, A. R. Fry, R. Redmer, F. Fiuza, D. O. Gericke, and S. H. Glenzer

Subjects
non-equilibrium plasma, electron-ion equilibration, warm dense hydrogen, x-ray thomson scattering, ultrafast x-ray scattering, Physics, QC1-999
Abstract

Angularly resolved X-ray scattering measurements from fs-laser heated hydrogen have been used to determine the equilibration of electron and ion temperatures in the warm dense matter regime. The relaxation of rapidly heated cryogenic hydrogen is visualized using 5.5 keV X-ray pulses from the Linac Coherent Light (LCLS) source in a 1 Hz repetition rate pump-probe setting. We demonstrate that the electron-ion energy transfer is faster than quasi-classical Landau-Spitzer models that use ad hoc cutoffs in the Coulomb logarithm.

Published
2022
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77. Experimental demonstration of an inertial collimation mechanism in nested outflows

Author

Yurchak, R., Ravasio, A., Pelka, A., Pikuz Jr., S., Falize, E., Vinci, T., Koenig, M., Loupias, B., Benuzzi-Mounaix, A., Fatenejad, M., Tzeferacos, P., Lamb, D. Q., and Blackman, E. G.

Subjects
Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Astrophysics of Galaxies, Astrophysics - Solar and Stellar Astrophysics, Physics - Plasma Physics
Abstract

Interaction between a central outflow and a surrounding wind is common in astrophysical sources powered by accretion. Understanding how the interaction might help to collimate the inner central outflow is of interest for assessing astrophysical jet formation paradigms. In this context, we studied the interaction between two nested supersonic plasma flows generated by focusing a long pulse high-energy laser beam onto a solid target. A nested geometry was created by shaping the energy distribution at the focal spot with a dedicated phase plate. Optical and X-ray diagnostics were used to study the interacting flows. Experimental results and numerical hydrodynamic simulations indeed show the formation of strongly collimated jets. Our work experimentally confirms the "shock-focused inertial confinement" mechanism proposed in previous theoretical astrophysics investigations., Comment: 6 pages, 5 figures, 1 table; accepted by Physical Review Letters

Published
2014
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78. Measures of infection prevention and incidence of SARS-CoV-2 infections in cancer patients undergoing radiotherapy in Germany, Austria and Switzerland

Author

Matuschek, Christiane, Fischer, Johannes C., Combs, Stephanie E., Fietkau, Rainer, Corradini, Stefanie, Zänker, Kurt, Bölke, Edwin, Djiepmo-Njanang, Freddy-Joel, Tamaskovics, Balint, Fischer, Joachim E., Stuschke, Martin, Pöttgen, Christoph, Förster, Robert, Zwahlen, Daniel R., Papachristofilou, Alexandros, Ganswindt, Ute, Pelka, Rainer, Schneider, E. Marion, Feldt, Torsten, Jensen, Björn Erik Ole, Häussinger, Dieter, Knoefel, Wolfram Trudo, Kindgen-Milles, Detlef, Pedoto, Alessia, Grebe, Olaf, van Griensven, Martijn, Budach, Wilfried, and Haussmann, Jan

Published
2020
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79. Full susceptibility tensor for localized spin models with S=1, 3/2, 2, 5/2 and with rhombic anisotropy

Author

Pelka, R.

Subjects
Condensed Matter - Other Condensed Matter, Condensed Matter - Strongly Correlated Electrons
Abstract

A general discussion of the simulation procedure of the full susceptibility tensor and isothermal magnetization pseudovector for compounds comprising weakly-interacting magnetic centers is presented. A single-crystal-sample as well as a powder-sample case are considered. The procedure is used to obtain explicit expressions for the full susceptibility tensor for spins S=1, 3/2, 2, and 5/2 for non-vanishing rhombic local anisotropy and any form of spectroscopic tensor., Comment: 26 pages, 6 figures

Published
2013

80. Magnetic systems at criticality: different signatures of scaling

Author

Pelka, R., Konieczny, P., Fitta, M., Czapla, M., Zielinski, P. M., Balanda, M., Wasiutynski, T., Miyazaki, Y., Inaba, A., Pinkowicz, D., and Sieklucka, B.

Subjects
Condensed Matter - Strongly Correlated Electrons
Abstract

Different aspects of critical behaviour of magnetic materials are presented and discussed. The scaling ideas are shown to arise in the context of purely magnetic properties as well as in that of thermal properties as demonstrated by magnetocaloric effect or combined scaling of excess entropy and order parameter. Two non-standard approaches to scaling phenomena are described. The presented concepts are exemplified by experimental data gathered on four representatives of molecular magnets., Comment: 33 pages, 16 figures

Published
2013
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81. Magnetocaloric effect in {[Fe(pyrazole)$_4$]$_2$[Nb(CN)$_8$]$\cdot$4H$_2$O}$_n$ molecular magnet

Author

Pelka, R., Konieczny, P., Zielinski, P. M., Wasiutynski, T., Miyazaki, Y., Inaba, A., Pinkowicz, D., and Sieklucka, B.

Subjects
Condensed Matter - Materials Science, Condensed Matter - Strongly Correlated Electrons
Abstract

Magnetocaloric effect in {[Fe(pyrazole)$_4$]$_2$[Nb(CN)$_8$]$\cdot$4H$_2$O}$_n$ molecular magnet is reported. It crystallizes in tetragonal I4$_1$/a space group. The compound exhibits a phase transition to a long range magnetically ordered state at $T_\mathrm{c}\approx$8.3 K. The magnetic entropy change $\Delta S_\mathrm{M}$ as well as the adiabatic temperature change $\Delta T_\mathrm{ad}$ due to applied field change $\mu_0\Delta H$=0.1, 0.2, 0.5, 1, 2, 5, 9 T as a function of temperature have been determined by the relaxation calorimetry measurements. The maximum value of $\Delta S_\mathrm{M}$ for $\mu_0\Delta H=5$ T is 4.9 J mol$^{-1}$ K$^{-1}$ (4.8 J kg$^{-1}$ K$^{-1}$) at 10.3 K. The corresponding maximum value of $\Delta T_\mathrm{ad}$ is 2.0 K at 8.9 K. The temperature dependence of the exponent $n$ characterizing the field dependence of $\Delta S_\mathrm{M}$ has been estimated. It attains the value of 0.64 at the transition temperature, which is consistent with the 3D Heisenberg universality class., Comment: 16 pages, 6 figures

Published
2013
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82. A New Player for Tackling Inequalities? Framing the Social Value and Impact of the Maker Movement

Author

Elisabeth Unterfrauner, Margit Hofer, Bastian Pelka, and Marthe Zirngiebl

Subjects
maker movement, maker space, social impact, social inclusion, social inequalities, Sociology (General), HM401-1281
Abstract

The Maker Movement has raised great expectations towards its potential for tackling social inequalities by mediating technology-related skills to everybody. Are maker spaces new players for social inclusion in digital societies? How can this potential impact be framed? While scientific discourse has so far identified broad value and impact dimensions of the Maker Movement, this article adds empirical insight into the potential for tackling social inequalities. The study is based on 39 interviews with makers and managers of maker initiatives and ten self-reporting surveys filled in by maker initiative managers throughout Europe, which have been analyzed qualitatively. We found four main domains in which makers address social inclusion: First, by mediating skills and competences not only in the field of digital technologies but in the broader sense of empowering people to “make” solutions for encountered problems. Second, we found that makers actively strive to provide democratized access to digital fabrication and the knowledge on how to use them. Third and fourth, we found different ambitions articulated by makers to change society and social practices towards a society providing better opportunities for individuals. As an entry point for further research and actions, we derived a maker typology that reflects the diverse and various types of relationships to be found in the maker community. This typology could be used for exploring further collaborations between social actors and the Maker Movement. We conclude with an outlook on potential trajectories of the Maker Movement and specify which could influence the inclusion of marginalized persons.

Published
2020
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84. ES-dRNN: A Hybrid Exponential Smoothing and Dilated Recurrent Neural Network Model for Short-Term Load Forecasting

Author

Smyl, Slawek, Dudek, Grzegorz, and Pelka, Pawel

Abstract

Short-term load forecasting (STLF) is challenging due to complex time series (TS) which express three seasonal patterns and a nonlinear trend. This article proposes a novel hybrid hierarchical deep-learning (DL) model that deals with multiple seasonality and produces both point forecasts and predictive intervals (PIs). It combines exponential smoothing (ES) and a recurrent neural network (RNN). ES extracts dynamically the main components of each individual TS and enables on-the-fly deseasonalization, which is particularly useful when operating on a relatively small dataset. A multilayer RNN is equipped with a new type of dilated recurrent cell designed to efficiently model both short and long-term dependencies in TS. To improve the internal TS representation and thus the model’s performance, RNN learns simultaneously both the ES parameters and the main mapping function transforming inputs into forecasts. We compare our approach against several baseline methods, including classical statistical methods and machine learning (ML) approaches, on STLF problems for 35 European countries. The empirical study clearly shows that the proposed model has high expressive power to solve nonlinear stochastic forecasting problems with TS including multiple seasonality and significant random fluctuations. In fact, it outperforms both statistical and state-of-the-art ML models in terms of accuracy.

Published
2024
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85. Disability in the Civil War Era

Author

Handley-Cousins, Sarah, Barclay, Jenifer L., Williams Eaton, Moyra, Franzino, Jean, Johnson, Allison M., and Pelka, Fred

Abstract

Abstract:This essay features a discussion among several scholars of disability in the Civil War era on the major themes and issues within this small field. The panelists, including both historians and literature scholars, reflect the interdisciplinary nature of disability studies and make the case for why disability analysis is critical to understanding of the Civil War era. Disability, they argue, enriches our studies of slavery and freedom, military service, federal power and bureaucracy, the home front and veteranhood. The panelists also consider paths for future research, such as increasing our use of material history and exploring disabled lives during Reconstruction.

Published
2024

86. Paired phases and Bose-Einstein condensation of spin-one bosons with attractive interaction

Author

Pelka, G., Byczuk, K., and Tworzydlo, J.

Subjects
Condensed Matter - Quantum Gases
Abstract

We analyze paired phases of cold bosonic atoms with the hyper spin S=1 and with an attractive interaction. We derive mean-field self-consistent equations for the matrix order parameter describing such paired bosons on an optical lattice. The possible solutions are classified according to their symmetries. In particular, we find that the self-consistent equations for the SO(3) symmetric phase are of the same form as those for the scalar bosons with the attractive interaction. This singlet phase may exhibit either the BCS type pairing instability (BCS phase) or the BEC quasiparticle condensation together with the BCS type pairing (BEC phase) for an arbitrary attraction U_0 in the singlet channel of the two body interaction. We show that both condensate phases become stable if a repulsion U_2 in the quintet channel is above a critical value, which depends on U_0 and other thermodynamic parameters., Comment: 9 pages, 4 figures

Published
2010
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87. Structural and electron spin state changes in an x-ray heated iron carbonate system at the Earth's lower mantle pressures

Author

Johannes M. Kaa, Christian Sternemann, Karen Appel, Valerio Cerantola, Thomas R. Preston, Christian Albers, Mirko Elbers, Lélia Libon, Mikako Makita, Alexander Pelka, Sylvain Petitgirard, Christian Plückthun, Vladimir Roddatis, Christoph J. Sahle, Georg Spiekermann, Christian Schmidt, Anja Schreiber, Robin Sakrowski, Metin Tolan, Max Wilke, Ulf Zastrau, and Zuzana Konôpková

Subjects
Physics, QC1-999
Abstract

The determination of the spin state of iron-bearing compounds at high pressure and temperature is crucial for our understanding of chemical and physical properties of the deep Earth. Studies on the relationship between the coordination of iron and its electronic spin structure in iron-bearing oxides, silicates, carbonates, iron alloys, and other minerals found in the Earth's mantle and core are scarce because of the technical challenges to simultaneously probe the sample at high pressures and temperatures. We used the unique properties of a pulsed and highly brilliant x-ray free electron laser (XFEL) beam at the High Energy Density (HED) instrument of the European XFEL to x-ray heat and probe samples contained in a diamond anvil cell. We heated and probed with the same x-ray pulse train and simultaneously measured x-ray emission and x-ray diffraction of an FeCO_{3} sample at a pressure of 51 GPa with up to melting temperatures. We collected spin state sensitive Fe Kβ_{1,3} fluorescence spectra and detected the sample's structural changes via diffraction, observing the inverse volume collapse across the spin transition. During x-ray heating, the carbonate transforms into orthorhombic Fe_{4}C_{3}O_{12} and iron oxides. Incipient melting was also observed. This approach to collect information about the electronic state and structural changes from samples contained in a diamond anvil cell at melting temperatures and above will considerably improve our understanding of the structure and dynamics of planetary and exoplanetary interiors.

Published
2022
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90. In Mitosis You Are Not: The NIMA Family of Kinases in Aspergillus, Yeast, and Mammals

Author

Scott Bachus, Drayson Graves, Lauren Fulham, Nikolas Akkerman, Caelan Stephanson, Jessica Shieh, and Peter Pelka

Subjects
NIMA kinases, Nek, mitosis, cell cycle, DNA damage, ciliogenesis, Biology (General), QH301-705.5, Chemistry, QD1-999
Abstract

The Never in mitosis gene A (NIMA) family of serine/threonine kinases is a diverse group of protein kinases implicated in a wide variety of cellular processes, including cilia regulation, microtubule dynamics, mitotic processes, cell growth, and DNA damage response. The founding member of this family was initially identified in Aspergillus and was found to play important roles in mitosis and cell division. The yeast family has one member each, Fin1p in fission yeast and Kin3p in budding yeast, also with functions in mitotic processes, but, overall, these are poorly studied kinases. The mammalian family, the main focus of this review, consists of 11 members named Nek1 to Nek11. With the exception of a few members, the functions of the mammalian Neks are poorly understood but appear to be quite diverse. Like the prototypical NIMA, many members appear to play important roles in mitosis and meiosis, but their functions in the cell go well beyond these well-established activities. In this review, we explore the roles of fungal and mammalian NIMA kinases and highlight the most recent findings in the field.

Published
2022
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91. Perturbative expansion for the half-integer rectilinear disclination line in the Landau-de Gennes theory

Author

Arodz, H. and Pelka, R.

Subjects
Condensed Matter - Soft Condensed Matter
Abstract

The structure of the half-integer rectilinear disclination line within the framework of the Landau-de Gennes effective theory of nematic liquid crystals is investigated. The consistent perturbative expansion is constructed for the case of $L_2\neq 0$. It turns out that such expansion can be performed around only a discrete subset of an infinite set of the degenerate zeroth order solutions. These solutions correspond to the positive and negative wedge disclination lines and to four configurations of the twist disclination line. The first order corrections to both the order parameter field as well as the free energy of the disclination lines have been found. The results for the free energy are compared with the ones obtained in the Frank-Oseen-Zocher director description., Comment: 34 pages, 3 eps figures

Published
2003

92. Phase transition lowering in dynamically compressed silicon

Author

McBride, E. E., Krygier, A., Ehnes, A., Galtier, E., Harmand, M., Konôpková, Z., Lee, H. J., Liermann, H.-P., Nagler, B., Pelka, A., Rödel, M., Schropp, A., Smith, R. F., Spindloe, C., Swift, D., Tavella, F., Toleikis, S., Tschentscher, T., Wark, J. S., and Higginbotham, A.

Published
2019
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93. Remarks on the n=1/2 disclination line in Landau-de Gennes theory of nematic liquid crystals

Author

Arodź, H. and Pełka, R.

Subjects
Condensed Matter - Soft Condensed Matter
Abstract

Using Landau-de Gennes effective theory for nematic liquid crystals we analyse the structure of rectilinear n=1/2 smooth disclination line in the case of equal elastic constants. We find that at certain temperature there is an exact mathematical correspondence with a rectilinear vortex in superfluid $^4He$. With a help of polynomial approximation difference of free energies of the smooth and of a singular disclination lines is estimated. It turns out that the smooth disclination line is energetically preferred only if temperature is low enough. At higher temperatures a disordered core should be expected., Comment: 17 pages, 6 eps figures. Acknowledgement is added and certain parts of text are improved

Published
2001

94. Perturbations of planar interfaces in Ginzburg-Landau models

Author

Arodz, H., Pelka, R., and Stepien, L.

Subjects
Condensed Matter - Soft Condensed Matter
Abstract

Certain dissipative Ginzburg-Landau models predict existence of planar interfaces moving with constant velocity. In most cases the interface solutions are hard to obtain because pertinent evolution equations are nonlinear. We present a systematic perturbative expansion which allows us to compute effects of small terms added to the free energy functional of a soluble model. As an example, we take the exactly soluble model with single order parameter $\phi$ and the potential $V_0(\phi) = A\phi^2 + B \phi^3 + \phi^4$, and we perturb it by adding $V_1(\phi) = {1/2} \epsilon_1 \phi^2 \partial_i \phi \partial_i \phi + 1/5 \epsilon_2 \phi^5 + 1/6 \epsilon_3 \phi^6. $ We discuss the corresponding changes of the velocity of the planar interface., Comment: 13 pages, no figures, LaTeX2e

Published
2001

95. Evolution of interfaces and expansion in width

Author

Arodz, H. and Pelka, R.

Subjects
Condensed Matter - Soft Condensed Matter, High Energy Physics - Theory
Abstract

Interfaces in a model with a single, real nonconserved order parameter and purely dissipative evolution equation are considered. We show that a systematic perturbative approach, called the expansion in width and developed for curved domain walls, can be generalized to the interfaces. Procedure for calculating curvature corrections is described. We also derive formulas for local velocity and local surface tension of the interface. As an example, evolution of spherical interfaces is discussed, including an estimate of critical size of small droplets., Comment: Discussion of stability of the interface is added, and the numerical estimates of width and velocity of the interface in the liquid crystal example are corrected. 25 pages, Latex2e

Published
2000
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96. Probing ultrafast laser plasma processes inside solids with resonant small-angle x-ray scattering

Author

Lennart Gaus, Lothar Bischoff, Michael Bussmann, Eric Cunningham, Chandra B. Curry, Juncheng E, Eric Galtier, Maxence Gauthier, Alejandro Laso García, Marco Garten, Siegfried Glenzer, Jörg Grenzer, Christian Gutt, Nicholas J. Hartley, Lingen Huang, Uwe Hübner, Dominik Kraus, Hae Ja Lee, Emma E. McBride, Josefine Metzkes-Ng, Bob Nagler, Motoaki Nakatsutsumi, Jan Nikl, Masato Ota, Alexander Pelka, Irene Prencipe, Lisa Randolph, Melanie Rödel, Youichi Sakawa, Hans-Peter Schlenvoigt, Michal Šmíd, Franziska Treffert, Katja Voigt, Karl Zeil, Thomas E. Cowan, Ulrich Schramm, and Thomas Kluge

Subjects
Physics, QC1-999
Abstract

Extreme states of matter exist throughout the universe, e.g., inside planetary cores, stars, or astrophysical jets. Such conditions can be generated in the laboratory in the interaction of powerful lasers with solids. Yet, the measurement of the subsequent plasma dynamics with regard to density, temperature, and ionization is a major experimental challenge. However, ultrashort x-ray pulses provided by x-ray free electron lasers (XFELs) allow for dedicated studies, which are highly relevant to study laboratory astrophysics, laser-fusion research, or laser-plasma-based particle acceleration. Here we report on experiments that employ a novel ultrafast method, which allows us to simultaneously access temperature, ionization state, and nanometer scale expansion dynamics in high-intensity, laser-driven, solid-density plasmas with a single x-ray detector. Using this method, we gain access to the expansion dynamics of a buried layer in compound samples, and we measure opacity changes arising from bound-bound resonance transitions in highly ionized copper. The presence of highly ionized copper leads to a temperature estimate of at least 2 million Kelvin already after the first 100 fs following the high-intensity laser irradiation. More specifically, we make use of asymmetries in small-angle x-ray scattering (SAXS) patterns, which arise from different spatial distributions of absorption and scattering cross sections in nanostructured grating samples when we tune an XFEL to atomic resonant energies of copper. Thereby, changes in asymmetry can be connected with the evolution of the plasma expansion and ionization dynamics. The potential of XFEL-based resonant SAXS to obtain three-dimensional ultrafast, nanoscopic information on density and opacity may offer a unique path for the characterization of dynamic processes in high energy density plasmas.

Published
2021
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97. Face masks: benefits and risks during the COVID-19 crisis

Author

Matuschek, Christiane, Moll, Friedrich, Fangerau, Heiner, Fischer, Johannes C., Zänker, Kurt, van Griensven, Martijn, Schneider, Marion, Kindgen-Milles, Detlef, Knoefel, Wolfram Trudo, Lichtenberg, Artur, Tamaskovics, Balint, Djiepmo-Njanang, Freddy Joel, Budach, Wilfried, Corradini, Stefanie, Häussinger, Dieter, Feldt, Torsten, Jensen, Björn, Pelka, Rainer, Orth, Klaus, Peiper, Matthias, Grebe, Olaf, Maas, Kitti, Gerber, Peter Arne, Pedoto, Alessia, Bölke, Edwin, and Haussmann, Jan

Published
2020
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99. The history and value of face masks

Author

Matuschek, Christiane, Moll, Friedrich, Fangerau, Heiner, Fischer, Johannes C., Zänker, Kurt, van Griensven, Martijn, Schneider, Marion, Kindgen-Milles, Detlef, Knoefel, Wolfram Trudo, Lichtenberg, Artur, Tamaskovics, Bálint, Djiepmo-Njanang, Freddy Joel, Budach, Wilfried, Corradini, Stefanie, Häussinger, Dieter, Feldt, Torsten, Jensen, Björn, Pelka, Rainer, Orth, Klaus, Peiper, Matthias, Grebe, Olaf, Maas, Kitti, Bölke, Edwin, and Haussmann, Jan

Published
2020
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100. Backreaction of excitations on a domain wall

Author

Pelka, R.

Subjects
High Energy Physics - Theory
Abstract

Backreaction of excitations on a planar domain wall in a real scalar field model is investigated in the cases of homogeneous, plane wave and wave packet type excitations. It is found that the excited domain wall radiates. The method of calculating backreaction for the general forms of excitations is also presented., Comment: 16 pages, LaTeX, no figures, to be published in Acta Physica Polonica B

Published
1997

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