Influence of working gas pulse injection and fluctuations of the magnetic field on the runaway electrons dynamics in Uragan-3M

Generation of runaway electrons in fusion experiments can drive to serious damage of plasma devices components. Injection of gas with a large mass number decreases the generation processes. Also, magnetic perturbations decrease generation of runaway electrons by increasing the loss rate. We investigated the influence of working gas pulse injection and natural fluctuations of the magnetic confining field on runaway electrons dynamics. The interaction of runaway electrons with an Alfven wave in plasma is noted.Генерація утікаючих електронів в експериментах синтезу може привести до серйозного пошкодження компонентів плазмових пристроїв. Інжекція важкого газу зменшує процеси генерації. Магнітні збурення також пригнічують генерацію утікаючих електронів за рахунок збільшення швидкості втрат. Досліджено вплив імпульсного напуску газу і природних флуктуацій утримуючого магнітного поля на динаміку утікаючих електронів. Відзначено взаємодія утікаючих електронів з альфвеновською хвилею в плазмі.Генерация убегающих электронов в экспериментах синтеза может привести к серьезному повреждению компонентов плазменных устройств. Инжекция тяжелого газа уменьшает процессы генерации. Магнитные возмущения также подавляют генерацию убегающих электронов за счет увеличения скорости потерь. Исследовалось влияние импульсного напускающего газа и естественных флуктуаций удерживающего магнитного поля на динамику убегающих электронов. Отмечено взаимодействие убегающих электронов с альфвеновской волной в плазме

Amplification of the runaway electrons flow in the Uragan-3М torsatron

In this work the results of amplification of the runaway electrons flow and interaction runaway electrons with RF-heating wave on the Uragan-3M torsatron are presented. Results described in the article confirm using runaway electrons for gas breakdown. The results allow making some recommendations for using of self-created flows of accelerated particles for stimulation of gas breakdown.Наведено результати експериментальних досліджень щодо посилення потоку утікаючих електронів, а також взаємодії потоку утікаючих електронів з електромагнітним полем хвилі, що збуджується високочастотним імпульсом у торсатроні Ураган-3М. Отримані результати підтверджують можливість пробою газу утікаючими електронами. Це дозволяє представити ряд рекомендацій по використанню потоків прискорених частинок для стимуляції високочастотного пробою.Приведены результаты экспериментальных исследований по усилению потока убегающих электронов, а также взаимодействию потока убегающих электронов с электромагнитным полем волны, возбуждаемой высокочастотным импульсом в торсатроне Ураган-3М. Полученные результаты подтверждают возможность пробоя газа убегающими электронами. Это позволяет представить ряд рекомендаций по использованию самопроизвольно формирующихся потоков ускоренных частиц для стимуляции высокочастотного пробоя

Partonic flow and ϕ\phi-meson production in Au+Au collisions at sNN\sqrt{s_{NN}} = 200 GeV

We present first measurements of the $\phi$-meson elliptic flow ($v_{2}(p_{T})$) and high statistics $p_{T}$ distributions for different centralities from $\sqrt{s_{NN}}$ = 200 GeV Au+Au collisions at RHIC. In minimum bias collisions the $v_{2}$ of the $\phi$ meson is consistent with the trend observed for mesons. The ratio of the yields of the $\Omega$ to those of the $\phi$ as a function of transverse momentum is consistent with a model based on the recombination of thermal $s$ quarks up to $p_{T}\sim 4$ GeV/$c$, but disagrees at higher momenta. The nuclear modification factor ($R_{CP}$) of $\phi$ follows the trend observed in the $K^{0}_{S}$ mesons rather than in $\Lambda$ baryons, supporting baryon-meson scaling. Since $\phi$-mesons are made via coalescence of seemingly thermalized $s$ quarks in central Au+Au collisions, the observations imply hot and dense matter with partonic collectivity has been formed at RHIC.Comment: 6 pages, 4 figures, submit to PR

Velocity-space sensitivity of the time-of-flight neutron spectrometer at JET

The velocity-space sensitivities of fast-ion diagnostics are often described by so-called weight functions. Recently, we formulated weight functions showing the velocity-space sensitivity of the often dominant beam-target part of neutron energy spectra. These weight functions for neutron emission spectrometry (NES) are independent of the particular NES diagnostic. Here we apply these NES weight functions to the time-of-flight spectrometer TOFOR at JET. By taking the instrumental response function of TOFOR into account, we calculate time-of-flight NES weight functions that enable us to directly determine the velocity-space sensitivity of a given part of a measured time-of-flight spectrum from TOFOR

Energy dependence of charged pion, proton and anti-proton transverse momentum spectra for Au+Au collisions at \sqrt{s_NN} = 62.4 and 200 GeV

We study the energy dependence of the transverse momentum (pT) spectra for charged pions, protons and anti-protons for Au+Au collisions at \sqrt{s_NN} = 62.4 and 200 GeV. Data are presented at mid-rapidity (|y| < 0.5) for 0.2 < pT < 12 GeV/c. In the intermediate pT region (2 < pT < 6 GeV/c), the nuclear modification factor is higher at 62.4 GeV than at 200 GeV, while at higher pT (pT >7 GeV/c) the modification is similar for both energies. The p/pi+ and pbar/pi- ratios for central collisions at \sqrt{s_NN} = 62.4 GeV peak at pT ~ 2 GeV/c. In the pT range where recombination is expected to dominate, the p/pi+ ratios at 62.4 GeV are larger than at 200 GeV, while the pbar/pi- ratios are smaller. For pT > 2 GeV/c, the pbar/pi- ratios at the two beam energies are independent of pT and centrality indicating that the dependence of the pbar/pi- ratio on pT does not change between 62.4 and 200 GeV. These findings challenge various models incorporating jet quenching and/or constituent quark coalescence.Comment: 19 pages and 6 figure

Relationship of edge localized mode burst times with divertor flux loop signal phase in JET

A phase relationship is identified between sequential edge localized modes (ELMs) occurrence times in a set of H-mode tokamak plasmas to the voltage measured in full flux azimuthal loops in the divertor region. We focus on plasmas in the Joint European Torus where a steady H-mode is sustained over several seconds, during which ELMs are observed in the Be II emission at the divertor. The ELMs analysed arise from intrinsic ELMing, in that there is no deliberate intent to control the ELMing process by external means. We use ELM timings derived from the Be II signal to perform direct time domain analysis of the full flux loop VLD2 and VLD3 signals, which provide a high cadence global measurement proportional to the voltage induced by changes in poloidal magnetic flux. Specifically, we examine how the time interval between pairs of successive ELMs is linked to the time-evolving phase of the full flux loop signals. Each ELM produces a clear early pulse in the full flux loop signals, whose peak time is used to condition our analysis. The arrival time of the following ELM, relative to this pulse, is found to fall into one of two categories: (i) prompt ELMs, which are directly paced by the initial response seen in the flux loop signals; and (ii) all other ELMs, which occur after the initial response of the full flux loop signals has decayed in amplitude. The times at which ELMs in category (ii) occur, relative to the first ELM of the pair, are clustered at times when the instantaneous phase of the full flux loop signal is close to its value at the time of the first ELM

Search for black holes and other new phenomena in high-multiplicity final states in proton-proton collisions at root s=13 TeV

Peer reviewe

Search for leptophobic Z ' bosons decaying into four-lepton final states in proton-proton collisions at root s=8 TeV

Peer reviewe

Measurements of differential production cross sections for a Z boson in association with jets in pp collisions at root s=8 TeV

Peer reviewe

Measurement of the mass difference between top quark and antiquark in pp collisions at root s=8 TeV

Peer reviewe