Characterization of the axial plasma shock in a table top plasma focus after the pinch and its possible application to testing materials for fusion reactors

Soto, Leopoldo; Pavez, Cristian; Moreno, José; Inestrosa-Izurieta, M. J.; Veloso, Felipe; Gutiérrez, Gonzalo; Vergara, Julio; Clausse, Alejandro; Bruzzone, H.; Castillo, F.; Delgado‐Aparicio, L.

doi:10.1063/1.4903471

Cited by 56 publications

(46 citation statements)

References 12 publications

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“…These self-scale plasma devices can generate neutron pulses [2][3][4], work as a pulsed X-ray source [5], produce plasma shocks [6], supersonic plasma jets [7], plasma filamentation [8], scaled astrophysical experiments [7] and they can also be used as a source to test new materials for the first wall of future fusion devices [9].…”

Section: Introductionmentioning

confidence: 99%

Electromagnetic Burst Measurement System Based on Low Cost UHF Dipole Antenna

et al. 2017

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Non-linear high-power devices produce electromagnetic noise (EMN) sources of great intensity that can disrupt and damage the surrounding electrical equipment and devices. This radiative phenomenon is very common at facilities where pulsed power generators are required, particularly those that are needed to produce dense transient plasma experiments. These conditions are found at the Chilean Nuclear Energy Commission (CCHEN), due to the presence of pulsed power generators that switch large currents (kA-MA) in short times (10-100 ns). In order to characterize and establish conditions to mitigate the effects of the EMN on nearby devices, a measurement system based on an ultra-high frequency (UHF) dipole antenna was developed. We evaluated the system measuring the EMN emanated from a plasma focus device, the PF-400J. Measurements at the place indicated broadband and intense electric fields that can couple to nearby cables and equipment (10-300 MHz bandwidth, up to 350 V/MHz spectral intensity, 100 V coupled voltage). Based on these measurements a compact and simple protection system was designed, built and tested, capable of effectively mitigating the high levels of EMN. The proper EMN impact mitigation indicates the correct operation of the suggested system. The developed system can be of interest to the energy community by facilitating EMN measurement produced by arc discharges.

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Section: Introductionmentioning

confidence: 99%

Electromagnetic Burst Measurement System Based on Low Cost UHF Dipole Antenna

et al. 2017

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“…В литературе не было приведено очевидных подтверждений в пользу того, в ка-кой области и в какой момент формируются потоки. Также при исследовании процессов формирования потоков многие исследователи наблюдали второстепенные эффекты (например, формирование ударной волны [26][27][28]), но не выявляли самого потока.…”

Section: выводыunclassified

Investigation of Forming Plasma Flow Generated in Plasma Focus Discharge

Ananyev¹,

Krauz²,

Myalton³

et al. 2017

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The pinch forming stage, which is the source of the axial plasma flow, was studied on the plasma focus facility PF-3 by means a highspeed photorecording. We focused on the recording initial moment of the flow generation. The combination of multiple slotted streaks being placed in different directions and at different distances from the anode plane has allowed to recreate the spatial picture of the axial plasma flows formation. Axial substance flows dynamics at different heights above the anode was recorded. Substance lows spreading faster (1.310 7 cm/s) than plasma, displaced by magnetic plunger along the axis (0.510 7 cm/s) were detected . Most likely, these substance flows are observed at a considerable distance from the anode in the form of compact jets. ВВЕДЕНИЕИзвестно, что плазменные потоки широко используются в различных областях науки и техники. Одним из направлений использования плазменных потоков является лабораторное моделирование астрофизических процессов, а именно генерации и распространения джетов. Значительный прогресс в моделировании астрофизических джетов достигнут с помощью мощных лазеров [1] и Z-пинчей [2,3]. Установки типа «плазменный фокус», принцип действия которых основан на пинчевании неци-линдрической токонесущей плазменной оболочки на оси системы, также известны как источники интенсивных плазменных потоков [4]. Анализ параметров этих потоков показывает, что они могут быть эффективно использованы для моделирования джетов молодых звёздных объектов. В НИЦ «Курчатовский институт» ведётся цикл работ по моделированию астрофизических джетов [5, 6]. Основной акцент этих экспериментов сделан на моделировании распространения джета в межзвёз д-ной среде. Базовые эксперименты выполняются на установке ПФ-3 (рабочий энергозапас до 1 МДж, ток на нагрузку до 4 MA). Получены результаты по определению формы и структуры плазменного потока, плотности и температуры как самого потока, так и фоновой плазмы, распределения захва-ченных магнитных полей [7][8][9][10]. Исследована динамика торможения потока в фоновой плазме в зависимости от сорта рабочего газа при его распространении на значительные расстояния (до 100 см) [11]. Промоделирована динамика сжатия токонесущей плазменной оболочки (ТПО) на ось [12] с образованием плотного пинча.

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“…This device has received renewed interest due to its widespread applications [9] and attractive compact designs achieved [10] with scaling laws [11]. Nowadays some applications of plasma focus include: pulsed source of X rays and/or neutrons [12]- [16], the production of plasma shocks [17], [18], as ion beam accelerator [19] and irradiation of biological cells [20].…”

Section: Introductionmentioning

confidence: 99%

“…The phenomena developed in the discharge process can be explained in six stages [4], [6], [20], [21]: I, the discharge of the capacitor bank produces the dielectric breakdown of the gas forming a current sheath (CS) over the insulator; II, the rundown process where the CS moves upwards along the anode due to the magnetic force; III, the compression phase at the end of the anode where the CS start to compress ionized gas; IV, the pinch phase where maximum compression of the ionized gas produces a highly dense plasma column; V, disruption of the pinch that produces an axial plasma shock [17] and, in addition, plasma jets are emitted from the top of the anode, VI [21]. In plasma focus devices, the pinch is typically regarded as the phase of most interest [4], [6].…”

Section: Introductionmentioning

confidence: 99%

Inference of X-Ray Emission From a Plasma Focus Discharge: Comparison Between Characteristic Parameters and Neural Network Analyses

et al. 2020

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Pulsed plasma discharges, such as the plasma focus, are a source of pulsed X rays, therefore it is desirable to understand the relationship between this fast transient phenomena and the electrical variables of the discharge. Parameters from the electrical diagnostic signals are typically used to characterize the plasma focus discharge and for the correlations with X rays measurements via scatter plots. To further evaluate relevant information in the electrical signals, besides the characteristic parameters, an implementation of different types of machine learning algorithms, that included deep learning, was performed. A classification of pulses associated with an X rays measurement, in terms of the electrical signals data as input, was carried out. Two approaches were compared: the selection of the characteristic parameters and the use of the entire signals so the algorithms could find additional information for the classification task. The electrical diagnostic signals corresponded to: the voltage at the electrodes of the discharge chamber measured with a resistive voltage divider; time variation of the circuit current measured with a Rogowski coil and an inductive loop sensor; and the electromagnetic burst from the circuit measured with a Vivaldi antenna. The X rays measurement corresponded to the signal obtained from a scintillator-photomultiplier. In terms of the performance of the algorithms models in this classification problem, the results indicated that there is no significative improvements when using the entire signal or the selection of characteristic parameters. The best results were obtained when the following parameters were used: voltage at time of gas breakdown, voltage at time of pinch, current at time of pinch, time derivative of current at time of pinch, time from breakdown to pinch, and the Fast Fourier Transform of the part of the Vivaldi antenna signal related to the pinch event.

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Characterization of the axial plasma shock in a table top plasma focus after the pinch and its possible application to testing materials for fusion reactors

Cited by 56 publications

References 12 publications

Electromagnetic Burst Measurement System Based on Low Cost UHF Dipole Antenna

Electromagnetic Burst Measurement System Based on Low Cost UHF Dipole Antenna

Investigation of Forming Plasma Flow Generated in Plasma Focus Discharge

Inference of X-Ray Emission From a Plasma Focus Discharge: Comparison Between Characteristic Parameters and Neural Network Analyses

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