FTTF/Marianska/18/Program/index

Program 2018

Po 22. 1.

18:30 Vojtěch Svoboda - Tokamaku GOLEM v roce 2017

  • Shrnutí pokračujících prací a novinek na tokamaku. Shrnutí akcí na tokamaku GOLEM konané v loňském roce a jejich vyhodnocení. Využití mikrovlnné předionizace. Prezentace

Út 23. 1.

9:00 Peter Švihra - Fast optical cameras based on a new silicon pixel sensor

  • We describe here fast optical cameras based on a new silicon pixel sensor, which in combination with the Timepix chips, will provide nanosecond scale time resolution and high quantum efficiency for photons with wavelength between 400 and 1050nm. Prezentace

10:00 Ondřej Kudláček - Plasma control challenge: disruption avoidance

  • One of the major showstoppers on the way towards tokamak fusion power plant are events called disruptions. Disruption is a sudden termination of the tokamak discharge (within a few ms) caused by failure of the tokamak control system or physics limit violation. In bigger machines that will be built in future, the mechanical and thermal effects of disruptions are expected to be so severe that these events are unacceptable. At the same time, it will not be acceptable to stop the tokamak discharge unless absolutely necessary. On the top of that, the future fusion reactor will have to operate much closer to both technical and physics limits than present day devices.

Presently, most of the research effort is focused on detection of incoming disruption and mitigation of disruption consequences. Even though this research is vital for future big machines, it is not sufficient by itself for high performance and at the same time disruption free operation required by a fusion power plant.

This talk will introduce a broad strategy for disruption avoidance that will be adopted on future tokamaks. It will be based on multiple defense line strategy: 1. Each discharge program will be checked by a flight simulator and possible dangerous situations will be detected in advance. 2. Actions preempting dangerous events that can lead to disruptions will be routinely taken even if nothing goes wrong with the discharge. 3. Detect any off-normal events and prepare appropriate actions to return to the normal state of the discharge 4. If all above fails, detect incoming disruption early enough and switch off the discharge. If not possible, mitigate the consequences.

Prezentace

11:00 Radek Pánek - Poslední informace a novinky: COMPASS Upgrade

  • Poslední informace a novinky: COMPASS Upgrade

17:00 Sergei Kulkov - Relativistic transparency of solid targets in laser-plasma interactions through 1D simulations

  • The main goal of this thesis is to study relativistic transparency of solid targets in laser-plasma interactions through 1D simulations. The thesis summarizes theoretical basis of such interactions. The Particle-In-Cell method and the EPOCH code, which was used for 1D simulations, are described. The states of the targets and the laser pulse profiles after the laser-plasma interactions are studied, in particular, the impact of the target’s width on the profile of the laser pulse. Besides width, the target’s electron density, laser pulse intensity and duration, which has an effect on plasma’s expansion, are crucial for transparency. For laser pulse of intensity 1022 W*cm-2 and duration 60 fs a 50 nm wide target is 52% transparent and generates laser pulse with 3 times faster increase of electric field amplitude. Prezentace

18:00 Valeria Istokskaia - Proposal of X rays and gamma detector for experiments on laser-driven ion acceleration.

  • Laser-accelerated ion beams can be potentially applied in multidisciplinary fields, e.g. in nuclear Physics, radiology and hadrontherapy. For these purposes ion beam should be properly characterized and theory of laser plasma interaction should be completely understood. Energy spectrum and spacial distribution of so called hot electrons can provide one with an important information about it, such as accelerated ions energy and fraction of laser absorption into hot electrons. To recover the spectrum it is possible to measure bremsstrahlung radiation from the plasma with the help of electromagnetic calorimeters. The presentation gives an overview of calorimeters used nowadays, choosing a detector for ELIMAIA group experiments and describes a prototype of Helmholtz Zentrum Dresden Rossendorf group that will collaborate with ELIMAIA to test it. Prezentace

20:00 Petr Kulhánek - Příběh vody: vznik, výskyt, skupenství, fáze

  • Příběh vody: vznik, výskyt, skupenství, fáze. Prezentace

St 24. 1.

9:00 Ondřej Ficker - RE beams and Impurity Influx

  • The talk summarizes recent results in two different topics that the speaker has been working on: 1) The recent experimental results achieved during the massive gas injection into the plasmas of the COMPASS tokamak that resulted in the generation of runaway electron beam. This beam is a potential threat for future fusion reactors. Similarly to other exp to other experimental tokamaks it was shown that the toroidal magnetic field is a critical parameter for the generation of such a beam. 2) An example of application of soft X-ray radiation tomographic reconstruction on the impurity (in particular W) influx during the 1,1 kink mode at JET. This particular topic allows a comparison with the state-of-the art modelling conducted by colleagues at Swiss Plasma Center, Lausanne. The heavy impurity influx significantly decreases the performance of the fusion plasmas. Prezentace

9:30 Michal Shkut - Perspectives of using superconductors in tokamaks

  • The purpose of this study is to show how important the development of superconductors is for fusion. This study includes basic principles of low- and high-temperature superconductors, techniques of creating superconductors and examples of use of superconductors in fusion devices (ITER, HTS-ST25, etc.). Prezentace

10:00 Jaroslav Čeřovský - 3D full orbit full orbit simulation for support RE diagnostics

  • In the past years experiments focused on observation of runaway electrons were conducted at the COMPASS tokamak. Measurements with one of the few detectors, which are capable of direct observation of losses of runaway electrons, were performed during last experimental campaigns. The Cherenkov-type detector is useful diagnostic tool for investigation of runaway electrons also due to possibility of setting energy threshold for detection of incoming particles. Despite above mentioned facts, the Cherenkov detector suffers from complicated interpretations of its results. The aim of this work is a full orbit simulation of trajectories of runaway electrons, which are escaping of the plasma and hit the first wall of the tokamak or limiter. The first step to realized the simulation in order to determined parameters of runaway electrons, which can be detected by the Cherenkov detector were done. Prezentace

19:00 Michal Farník - Diagnostika ubíhajících elektronů na tokamaku COMPASS pomocí EC emise

  • Byla představena metoda diagnostiky netermálních elektronů pomocí elektronové cyklotronní emise (ECE). Metoda využívá vertikálně zapojený radiometr o 16 kanálech s rozsahem 76,5 – 88,3 GHz. V prezentaci byly zmíněny základy teorie vzniku a šíření ECE z netermálních elektronů. Při splnění resonanční rovnice a podmínek pro správné měření jsme ze signálu schopní detekovat přítomnost RE. Proběhlo představení simulací, spolu s výsledky analýzy naměřených dat. Prezentace

20:00 Jakub Svoboda - Tomographic reconstruction of data, comparative analysis of data from tokamak JET

  • Presentation is focused on two topics. First is tomographic reconstruction of data from fast visible camera installed at COMPASS tokamak. Description of development and testing is given together with results from model data. Second topic is comparative analysis of data from tokamak JET. Specially created GUI for this purpose is described and preliminary results of comparative analysis are shown. Prezentace

Čt 25. 1.

9:00 Miroslav Šos - Optimisation of processing raw data from Thomson scattering diagnostic on the COMPASS tokamak

  • Assignment of presented diploma thesis progress status includes two main tasks, namely, development and implementation of raw data processing system for toka- mak diagnostics based on Thomson scattering (TS) and revision and check of necessary calibration routines. Firstly, theoretical background of Thomson scattering is presented and the realization of diagnostic on the COMPASS tokamak is used for illustration. Detection and data acquisition systems are shown, while the structure and content of acquired data is emphasised in order to describe the data processing algorithm properly. Current data processing system was analysed and detailed flow chart was created to identify particular segments. Raw data from fast digitisers are fitted using newly designed double Gaussian function to match the data more precisely. Obtained results are combined with the outcome of spectral, spatial and absolute calibration for the purpose of Thomson scattering spectrum reconstruction. Apart from the reconstruction itself, the whole process has been already implemented. Various optimisation methods have been implemented in order to provide more robust and modular data processing system. Prezentace

10:00 Ondřej Grover - Limit cycle oscillations and Reynolds stress measurements with Langmuir and ball-pen probes on COMPASS

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

11:00 Jaroslav Krbec - He-beam diagnostics

  • Svazky Helia v tokamacích - jejich využití, diagnostika Prezentace

19:00 Jana Brotánková - Projekty Joint Degree fúze a PlasmaLab@CTU

  • Seminář pojednává o dvou podporovaných projektech OP VVV. Jsou to: výzva 02_16_018 Rozvoj výzkumně zaměřených studijních programů (Joint Degree fúze) a výzva 02_16_017 Výzkumné infrastruktury pro vzdělávací účely – budování či modernizace (PlasmaLab@CTU). Projekty mají podporu v letech 2017 – 2022. Cílem projektu Joint degree fúze (plným názvem Mezinárodní doktorský program vysokoteplotního plazmatu a jaderné fúze) je akreditace joint degree s Univerzitou v Gentu. Cílem projektu PlasmaLab@CTU (plným názvem Laboratoř horkého plazmatu a fúzní techniky) je vybudovat vzdělávací laboratoř v oboru fyziky horkého plazmatu a techniky fúze v kombinaci s rozvojem tokamaku GOLEM. Prezentace shrne motivaci a cíle projektů, představí fázi, v jaké se nachází, a nastíní připravované úlohy. Presentace

20:00 Ján Uličný - Vehicle Detection Project

  • Perform a Histogram of Oriented Gradients (HOG) feature extraction on a labeled training set of images and train a classifier Linear SVM classifier Optionally, you can also apply a color transform and append binned color features, as well as histograms of color, to your HOG feature vector. Note: for those first two steps don’t forget to normalize your features and randomize a selection for training and testing. Implement a sliding-window technique and use your trained classifier to search for vehicles in images. Run your pipeline on a video stream (start with the test_video.mp4 and later implement on full project_video.mp4) and create a heat map of recurring detections frame by frame to reject outliers and follow detected vehicles. Estimate a bounding box for vehicles detected. Prezentace

Pá 26. 1.

9:00 Kateřina Jiráková - Třídění databáze výstřelů tokamaku COMPASS

  • Jakákoli statistická analýza na množině výstřelů tokamaku COMPASS vyžaduje nejprve, aby byla shromážděna co největší podmnožina použitelných výstřelů. Zde je na příkladu měření reciprokých sond představena detekce flat topu, reciprokace a správného měření ball-pen a Langmuirovy sondy. Sdílení výsledků této práce má potenciál prudce urychlit budoucí statistické analýzy. Prezentace

10:00 Jakub Veverka - Slitiny W s pasivačními vlastnostmi

  • Tungsten and its compounds belong to the fusion relevant materials, being the main candidates for the plasma facing components, for their good thermal conductivity, low sputtering yield and low tritium retention. However, poor mechanical properties, low recrystallization temperature and rapid oxidation might constitute a threat to the reactor safety. Regarding the oxidation behaviour, the so called “smart tungsten alloys” are currently investigated – compounds containing an element that form oxides even easier than tungsten. Therefore, after exposure to air, passivation layer is formed on the surface, preventing further tungsten oxidation connected with material degradation and radiation spreading. Prezentace

10:30 Vojtěch Svoboda - Shrnutí dosavadních výsledků a diskuse k dalšímu pokračování studentských vědeckých konferencí.

11:00 Zakončení konference