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Tytuł:
First dedicated observations of runaway electrons in the COMPASS tokama
Autorzy:
Vlainić, M.
Mlynář, J.
Weinzettl, V.
Papřok, R.
Imríšek, M.
Ficker, O.
Vondráček, P.
Havlíček, J.
Powiązania:
https://bibliotekanauki.pl/articles/971514.pdf
Data publikacji:
2015
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
plasma diagnostics
runaway electrons
tokamak
Opis:
Runaway electrons present an important part of the present efforts in nuclear fusion research with respect to the potential damage of the in-vessel components. The COMPASS tokamak a suitable tool for the studies of runaway electrons, due to its relatively low vacuum safety constraints, high experimental flexibility and the possibility of reaching the H-mode D-shaped plasmas. In this work, results from the first experimental COMPASS campaign dedicated to runaway electrons are presented and discussed in preliminary way. In particular, the first observation of synchrotron radiation and rather interesting raw magnetic data are shown.
Źródło:
Nukleonika; 2015, 60, 2; 249-255
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Main aspects and lessons from the ITER project governance
Autorzy:
Varandas, C.
Powiązania:
https://bibliotekanauki.pl/articles/147838.pdf
Data publikacji:
2012
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
fusion reactor
governance
ITER
tokamak
Opis:
ITER (International Tokamak Experimental Reactor), presently under construction at Cadarache, is a very important project in the path towards a nuclear fusion power plant. This paper addresses the main key aspects of the ITER governance, trying to take lessons for future international projects to be carried out in a world dominated by a global economy.
Źródło:
Nukleonika; 2012, 57, 2; 139-146
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Nuclear fusion and its large potential for the future world energy supply
Autorzy:
Ongena, J.
Powiązania:
https://bibliotekanauki.pl/articles/147328.pdf
Data publikacji:
2016
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
energy
nuclear fusion
tokamak
stellarator
Opis:
An overview of the energy problem in the world is presented. The colossal task of ‘decarbonizing’ the current energy system, with ~85% of the primary energy produced from fossil sources is discussed. There are at the moment only two options that can contribute to a solution: renewable energy (sun, wind, hydro, etc.) or nuclear fission. Their contributions, ~2% for sun and wind, ~6% for hydro and ~5% for fission, will need to be enormously increased in a relatively short time, to meet the targets set by policy makers. The possible role and large potential for fusion to contribute to a solution in the future as a safe, nearly inexhaustible and environmentally compatible energy source is discussed. The principles of magnetic and inertial confinement are outlined, and the two main options for magnetic confi nement, tokamak and stellarator, are explained. The status of magnetic fusion is summarized and the next steps in fusion research, ITER and DEMO, briefly presented.
Źródło:
Nukleonika; 2016, 61, 4; 425-432
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
COREDIV modelling of JET ILW discharges with different impurity seeding: nitrogen, neon, argon and krypton
Autorzy:
Ivanova-Stanik, I.
Zagórski, R.
Powiązania:
https://bibliotekanauki.pl/articles/148412.pdf
Data publikacji:
2017
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
impurity seeding
integrated modelling
tokamak
Opis:
Numerical simulations with the COREDIV code of JET H-mode discharges with 25 MW of auxiliary heating in the ITER-like wall (ILW) configuration with different impurity seedings – nitrogen (N), neon (Ne), argon (Ar) and krypton (Kr) – are presented. All simulations have been performed with the same transport model and input discharge parameters like auxiliary heating, volume average plasma density, confi nement factor. Only the seeded impurity puff rate was changed in the calculations. It appears that for the considered heating power of 25 MW and relatively low volume electron average density = 6.2 × 1019 m–3, impurity seeding is necessary. It has been found that for every gas at the maximum level of the seeding rate, allowed by the code convergence, the power to the plate is reduced up to 2–4 MW, with electron temperature at the plate of about 2 eV, indicating semi-detached conditions in the divertor region. It should be noted, however, that in cases with low and medium Z impurity (N, Ne and Ar), tungsten radiation is a signifi cant part of radiation losses and stays above 22–32% of the total energy losses, but for high Z impurity (Kr) it is reduced up to 10% of the total losses. The maximum of the Kr radiation is between the pedestal region and separatrix, showing that radiative mantle can be created, which might have a strong influence on the plasma parameters in the pedestal region.
Źródło:
Nukleonika; 2017, 62, 1; 3-7
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
High kinetic energy dense plasma jet
Autorzy:
Voronin, A.
Gusev, V.
Petrov, Y.
Sakharov, N.
Abramova, K.
Hellblom, K.
Powiązania:
https://bibliotekanauki.pl/articles/147488.pdf
Data publikacji:
2006
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
plasma gun
spherical tokamak
fuelling system
Opis:
Researches on the plasma jet source and injection of hydrogen plasma and neutral gas jets into the Globus-M spherical tokamak are presented. A novel source of dense plasma with high directed velocity is designed, constructed and investigated. This is a double stage system consisting of an intense source utilizing titanium-hydride grains for neutral gas production and a conventional pulsed coaxial accelerator. Optimization of the accelerator parameters, so as to achieve a maximum possible flow velocity with a limited discharge current and a reasonable length of the coaxial electrodes is performed. The calculations are compared with the experiment. A test bed is used for investigation of the intense plasma jet generated by a plasma gun. Plasma jet parameters, among them pressure distribution across the jet, flow velocity, plasma density etc., were measured. Plasma jets with densities of up to 1022 m 3, total numbers of accelerated particles (1 5) . 1019, and flow velocities of 50 100 km/s were successfully injected into the plasma column of the Globus-M tokamak. Interferometric and Thomson scattering measurements confirmed a deep jet penetration and a fast density rise (<0.5 ms) at all spatial points up to the radius r H 0.3a. The injection did not result in plasma degradation.
Źródło:
Nukleonika; 2006, 51, 1; 85-92
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dense plasma source development and jet injection in Globus-M*
Autorzy:
Voronin, , V. A.
Gusev, V. K.
Petrov, Y. V.
Mukhin, E. E.
Tolstyakov, S. Y.
Kurskiev, G. S.
Kochergin, M. M.
Hellblom, K. G.
Powiązania:
https://bibliotekanauki.pl/articles/147768.pdf
Data publikacji:
2008
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
plasma gun
spherical tokamak
fuelling system
Opis:
Progress in the development of a plasma jet source and its utilization for injection of hydrogen plasma and neutral gas jets into the Globus-M spherical tokamak are presented. The latest version of the high kinetic energy gas and plasma jet source with titanium hydride grains is described. Reproducibility of the gas jet generation was increased due to automatic loading of fresh grains into the source before every shot. It allows producing stable gas release for many discharges. Impurity radiation intensity from the plasma jet was decreased by more than 100 times by preliminary processing titanium hydrate grains and developing a new filter. The result of special experiments on two colliding jets is discussed. It was confirmed that the plasma jet recombines into a gas jet after it escapes the source edge and has a kinetic energy higher than the hydrogen ionization potential. Hydrogen plasma jet with low impurity content has a density up to 2 × 1022 m-3, a total number of accelerated particles (1-5) × 1019 and a flow velocity of ~ 200 km/s. It was used as an instrument for density control in Globus-M. Jet injection into deuterium plasma core during current plateau phase led to fast density increase in all spatial points of the plasma column including the plasma central region. Such injection allowed density doubling in the tokamak plasma. The model predictions are consistent with the experimental observations of the density raise recorded by the interferometer and Thomson scattering.
Źródło:
Nukleonika; 2008, 53, 3; 103-109
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Selected methods of electronand ion-diagnostics in tokamak scrape-off-layer
Autorzy:
Sadowski, M. J.
Powiązania:
https://bibliotekanauki.pl/articles/146123.pdf
Data publikacji:
2015
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
diagnostics
electrons
ions
fusion products
probes
tokamak
Opis:
This invited paper considers reasons why exact measurements of fast electron and ion losses in tokamaks, and particularly i n a scrape-off-layer and near a divertor region, are necessary in order to master nuclear fusion energy production. Attention is also paid to direct measurements of escaping fusion products from D-D and D-T reactions, and in particular of fast alphas which might be used for plasma heating. The second part describes the generation of so-called runaway and ripple-born electrons which might induce high energy losses and cause severe damages of internal walls in fusion facilities. Advantages and disadvantages of different diagnostic methods applied for studies of such fast electrons are discussed. Particular attention is paid to development of a direct measuring technique based on the Cherenkov effect which might be induced by fast electrons in appropriate radiators. There are presented various versions of Cherenkov-type probes which have been developed by the NCBJ team and applied in different tokamak experiments. The third part is devoted to direct measurements of fast ions (including those produced by the nuclear fusion reactions) which can escape from a high-temperature plasma region. Investigation of fast fusion-produced protons from tokamak discharges is reported. New ion probes, which were developed by the NCBJ team, are also presented. For the fi rst time there is given a detailed description of an ion pinhole camera, which enables irradiation of several nuclear track detectors during a single tokamak discharge, and a miniature Thomson-type mass-spectrometer, which can be used for ion measurements at plasma borders.
Źródło:
Nukleonika; 2015, 60, 2; 199-206
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optimization of soft X-ray tomography on the COMPASS tokamak
Autorzy:
Imríšek, M.
Mlynář, J.
Löffelmann, V.
Weinzettl, V.
Odstrčil, T.
Odstrčil, M.
Tomeš, M.
Powiązania:
https://bibliotekanauki.pl/articles/146251.pdf
Data publikacji:
2016
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
soft X-ray
tomography
Tikhonov regularization
tokamak
Opis:
The COMPASS tokamak is equipped with the soft X-ray (SXR) diagnostic system based on silicon photodiode arrays shielded by a thin beryllium foil. The diagnostic is composed of two pinhole cameras having 35 channels each and one vertical pinhole camera with 20 channels, which was installed recently to improve tomographic inversions. Lines of sight of the SXR detectors cover almost complete poloidal cross section of the COMPASS vessel with a spatial resolution of 1–2 cm and temporal resolution of about 3 s. Local emissivity is reconstructed via Tikhonov regularization constrained by minimum Fisher information that provides reliable and robust solution despite limited number of projections and ill-conditionality of this task. Improved border conditions and numerical differentiation matrices suppressing artifacts in reconstructed radiation were implemented in the code. Furthermore, a fast algorithm eliminating iterative processes was developed, and it is foreseen to be tested in real-time plasma control.
Źródło:
Nukleonika; 2016, 61, 4; 403-408
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Spektrometria aktywacyjna dla potrzeb drugiej kampanii deuterowo-trytowej na Tokamaku JET
The activation spectrometry for the purpose of the Second Deuterum-Tritium Experimental Campaign on JET tokamak
Autorzy:
Łaszyńska, E.
Jednoróg, S.
Powiązania:
https://bibliotekanauki.pl/articles/214258.pdf
Data publikacji:
2016
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
tokamak JET
metoda aktywacyjna
kalibracja diagnostyk neutronowych tokamaka JET
generator neutronów 14 MeV
wydajność neutronowa
JET tokamak
activation technique
alibration of neutron diagnostics for JET tokamak
14 MeV neutron
generator
neutron yield
Opis:
Metoda aktywacyjna stosowana do charakteryzacji różnych źródeł neutronów, należy do jednej z najstarszych metod stosowanych w neutronice. Pomimo tego jest wciąż ważna, gdyż prowadzi do otrzymywania wartości bezwzględnych wydajności neutronów, a czasami pozwala na dekonwolucje ich rozkładu energetycznego. Druga Deuterowo- Trytowa Kampania Eksperymentalna na Wspólnym Europejskim Tokamaku JET jest wielkim wyzwaniem. Po jej zakończeniu nastąpi zamknięcie i odstawienie JETa, a tym samym zakończenie jakże ważnego rozdziału w historii fizyki plazmy. Przed kampanią deuterowo-trytową nastąpi kalibracja diagnostyk neutronowych tokamaka i to z niepewnością niższą niż 5%. Technika aktywacyjna posłuży do charakteryzacji generatora neutronów, który będzie zastosowany, jako ustandaryzowane źródło neutronów 14 MeV, a następnie będzie zastosowana w czasie ostatniej kampanii eksperymentalnej do monitorowania wydajności neutronów.
The activation technique used for characterization of many different neutron sources belongs to the oldest one applied in neutronics area. It is still important because it leads to obtainment of obsolete value of neutron yield and from time to time allows neutron spectrum deconvolution. The Second Deuterium-Tritium Experimental Campaign that is held on Joint European Torus is a great challenge. After completing the above campaign the shut down and decommissioning of the JET is expected. Thus, the important chapter in history of plasma physics will be definitely closed. But before the deuterium-tritium campaign starts, the calibration of neutron diagnostic should be completed with uncertainty better than 5%. The activation technique is used for neutron diagnostics characterization that is chosen as the source of 14 MeV neutrons. Afterwards, the activation technique will be applied as neutron yield monitor during last experimental campaign on JET tokamak.
Źródło:
Postępy Techniki Jądrowej; 2016, 4; 21-29
0551-6846
Pojawia się w:
Postępy Techniki Jądrowej
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Generation and diagnostics of fast electrons within tokamak plasma
Autorzy:
Sadowski, M. J.
Powiązania:
https://bibliotekanauki.pl/articles/146620.pdf
Data publikacji:
2011
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
tokamak
runaway electrons
ripple-born electrons
Cherenkov detectors
Opis:
The first part of this invited paper is devoted to mechanisms of the production of fast electrons in plasma experiments involving magnetic traps of the tokamak type. The phenomenon of generation of the so-called runaway electrons - which may reach energies up to several dozen MeV - is considered and basic characteristics of such electrons are described. In particular, the orbits of the runaway electrons and their energy limits are presented. Problems related to the cross-field transport in tokamak plasmas and interactions of the relativistic electrons with plasma oscillations are also considered. Production of the so-called ripple-born electrons, which may be observed in the energy range from approximately 50 keV to several hundreds keV, is analyzed separately. In the second part of this paper various diagnostic methods used for investigation of the runaway and ripple-born electrons are presented. Various techniques are described, which are based on different reactions induced by the runaway electrons, e.g., the emission of X-rays or neutrons, or the synchrotron radiation. Finally, a modern technique of electron measurements is described, which was developed by the author's team at the Andrzej Sołtan Institute for Nuclear Studies (IPJ) in Świerk (Poland), and which is based on the use of Cherenkov-type detectors. Examples of applications of the discussed techniques in different tokamak experiments are described. Particular attention is paid to the Cherenkov detectors, which have already been used in experiments at the small-size CASTOR device in Prague (Czech Republic), the ISTTOK machine in Lisbon (Portugal), as well as in the larger TORE-SUPRA facility in Cadarache (France).
Źródło:
Nukleonika; 2011, 56, 2; 85-98
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Important problems of future thermonuclear reactors
Autorzy:
Sadowski, M. J.
Powiązania:
https://bibliotekanauki.pl/articles/148654.pdf
Data publikacji:
2015
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
fusion reactions
plasma
tokamak
power plant
thermonuclear reactor
Opis:
This paper concerns important and difficult problems connected with a design and construction of thermonuclear reactors, which have to use nuclear fusion reactions of heavy isotopes of hydrogen, i.e., deuterium (D) and tritium (T). There are described conditions in which such reactions can occur, and different methods of a high-temperature plasma generation, i.e., high-current electrical discharges, intense microwave pulses, and injection of energetic neutral atoms (NBI). There are also presented experimental facilities which can contain hot plasma for an appropriate period, and particularly so-called tokamaks. The second part presents the technical problems which must be solved in order to build a thermonuclear reactor, that might be used for energetic purposes. There are considered problems connected with a choice of constructional materials for a vacuum chamber, its internal parts, external windings generating a magnetic fi eld, and necessary shields. The next part considers the handling of radioactive tritium; the using of alpha particles (4He) for additional heating of plasma; recuperation of hydrogen isotopes absorbed in the tokamak internal parts, and a removal of a helium excess. There is presented a scheme of a future thermonuclear power plant and critical comments on a road map which should enable the construction of an industrial thermonuclear reactor (DEMO).
Źródło:
Nukleonika; 2015, 60, 2; 331-338
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mathematical Calculation of Material Reliability Using Surface Roughness Feature Based on Plasma Material Interaction Experiment Results
Autorzy:
Pahsa, Alper
Aydoğdu, Yıldırım
Göktaş, Fahrettin
Powiązania:
https://bibliotekanauki.pl/articles/27312789.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Polskie Naukowo-Techniczne Towarzystwo Eksploatacyjne PAN
Tematy:
tokamak
material reliability
Weibull
divertor
PMI
Plasma Material Interaction
Opis:
The choice of reactor structural material design must take into account the TOKAMAK fusion reactors' structural reliability. Due to their high levels of heat and energy, fusion reactions have significant deformation effects, which reduce the efficiency of energy production in reactors. Material selection, erosion and damage, heat and stress management, reliability analysis, maintenance, and inspection are crucial elements in determining how reliable fusion reactors are. The focus of this work is on material selection and reliability analysis based on these parameters. The most common wall materials used in fusion reactors are tungsten, beryllium, steel, or graphite. It is advised to utilize aluminum because harmful Beryllium dust limits the study of this element. For this purpose, a target of aluminum samples is established with a plasma of He ions created by glow discharge. The dependability of the samples is determined by calculating the Weibull Distribution and measuring the roughness of the sample surfaces following exposure.
Źródło:
Eksploatacja i Niezawodność; 2023, 25, 3; art. no. 169815
1507-2711
Pojawia się w:
Eksploatacja i Niezawodność
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Impurity studies for the ITER half-field ICRF heating scenarios in hydrogen plasmas on JET
Autorzy:
Czarnecka, A.
Lerche, E.
Ongena, J.
Van Eester, D.
Figueiredo, A. C. A.
Coffey, I. H.
Zastrow, K. -D.
Powiązania:
https://bibliotekanauki.pl/articles/147692.pdf
Data publikacji:
2012
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
tokamak
impurities
ICRF heating
ITER scenario
VUV plasma spectroscopy
Opis:
Two ion cyclotron range of frequencies (ICRF) heating scenarios, proposed for the non-activated half-B0 phase of ITER in hydrogen plasmas, were investigated on the JET tokamak. This paper we present a detailed study of the impurity content in plasma when the fundamental H and the 2nd harmonic 3He ICRF heating scenarios are realized. The ICRF conditions for those heating scenarios on ITER - i.e. the frequency of 42 MHz for the fundamental H and 53 MHz for the 2nd harmonic 3He heating, and the magnetic field B0 = 2.65 T – were closely reproduced in dedicated experiments on JET. The impurity content of the plasma was determined by means of the spectroscopy in the VUV range. The release of C and Ni impurities during the ICRF heating is presented as a function of the total ICRF heating power supplied in those heating scenarios. The contribution of the Ni impurity to the effective charge of the plasma, Zeff, and the plasma dilution are estimated. We find that for the 3He ICRF heating scenario the impurity content and the plasma energy loss through radiation was higher than for the fundamental hydrogen heating scenario.
Źródło:
Nukleonika; 2012, 57, 1; 25-30
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Progress in theoretical models of the ICRF mode conversion
Autorzy:
Kazakov, Y. O.
Powiązania:
https://bibliotekanauki.pl/articles/147690.pdf
Data publikacji:
2012
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
ICRF heating
ion-ion hybrid resonance
mode conversion
tokamak
Opis:
The technique of heating the plasma with the electromagnetic waves in the ion cyclotron range of frequencies (ICRF) has many important applications that may lead to improved performance of tokamaks. Recently the heating efficiency of the ICRF mode conversion scenarios characterized by a narrow power deposition profiles received much attention. This paper highlights progress in the theoretical models of the ICRF mode conversion that allowed to achieve a successful experimental realisation of these scenarios in present-day tokamaks.
Źródło:
Nukleonika; 2012, 57, 1; 31-35
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Thermal-hydraulic analysis of LTS cables for the DEMO TF coil using simplifi ed models
Autorzy:
Lewandowska, M.
Dembkowska, A.
Powiązania:
https://bibliotekanauki.pl/articles/146243.pdf
Data publikacji:
2017
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
DEMO
tokamak
low Tc superconductors
toroidal field coil
thermal-hydraulic analysis
Opis:
The conceptual design activities for the DEMOnstration reactor (DEMO) – the prototype fusion power plant – are conducted in Europe by the EUROfusion Consortium. In 2015, three design concepts of the DEMO toroidal field (TF) coil were proposed by Swiss Plasma Center (EPFL-SPC, PSI Villigen), Italian National Agency for New Technologies (ENEA Frascati), and Atomic Energy and Alternative Energies Commission (CEA Cadarache). The proposed conductor designs were subjected to complete mechanical, electromagnetic, and thermal-hydraulic analyses. The present study is focused on the thermal-hydraulic analysis of the candidate conductor designs using simplifi ed models. It includes (a) hydraulic analysis, (b) heat removal analysis, and (c) assessment of the maximum temperature and the maximum pressure in each conductor during quench. The performed analysis, aimed at verification whether the proposed design concepts fulfil the established acceptance criteria, provides the information for further improvements of the coil and conductors design.
Źródło:
Nukleonika; 2017, 62, 1; 23-28
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł

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