Irradiation damage on CrNbTaVWx high entropy alloys

ABSTRACT: CrNbTaVWx high-entropy alloys have been developed for plasma facing components to be applied in nuclear fusion reactors. The CrNbTaVWx (x = 1 and 1.7) compositions were prepared by ball milling and consolidated at 1600 degrees C under 90 MPa. To study the irradiation resistance of these materials, deuterium plasmas were used to irradiate the samples in the PF-1000U facility with 1 and 3 discharges. Structural changes before and after irradiation were analyzed by scanning electron microscopy coupled with energy dispersive X-ray spectroscopy. Nuclear reaction analysis was carried out with 1000 and 2300 keV 3He+ ion beams to evaluate the profile and amount of retained deuterium on the irradiated samples. After irradiation, the sample with higher W content revealed swelling and melting for all discharges, while in the case of CrNbTaVW only blisters were observed. The deuterium retention was higher for CrNbTaVW1.7 when compared with CrNbTaVW for 3 discharges applied.info:eu-repo/semantics/publishedVersio

Formation and Primary Heating of The Solar Corona - Theory and Simulation

An integrated Magneto-Fluid model, that accords full treatment to the Velocity fields associated with the directed plasma motion, is developed to investigate the dynamics of coronal structures. It is suggested that the interaction of the fluid and the magnetic aspects of plasma may be a crucial element in creating so much diversity in the solar atmosphere. It is shown that the structures which comprise the solar corona can be created by particle (plasma) flows observed near the Sun's surface - the primary heating of these structures is caused by the viscous dissipation of the flow kinetic energy.Comment: 46 pages including 7 pages of figures, Submitted to Phys.Plasma

Dense Plasma Focus: physics and applications (radiation material science, single-shot disclosure of hidden illegal objects, radiation biology and medicine, etc.)

The paper presents some outcomes obtained during the year of 2013 of the activity in the frame of the International Atomic Energy Agency Co-ordinated research project "Investigations of Materials under High Repetition and Intense Fusion-Relevant Pulses". The main results are related to the effects created at the interaction of powerful pulses of different types of radiation (soft and hard X-rays, hot plasma and fast ion streams, neutrons, etc. generated in Dense Plasma Focus (DPF) facilities) with various materials including those that are counted as perspective ones for their use in future thermonuclear reactors. Besides we discuss phenomena observed at the irradiation of biological test objects. We examine possible applications of nanosecond powerful pulses of neutrons to the aims of nuclear medicine and for disclosure of hidden illegal objects. Special attention is devoted to discussions of a possibility to create extremely large and enormously diminutive DPF devices and probabilities of their use in energetics, medicine and modern electronics

Experimental studies of the interaction of ion- and plasma-streams with carbon-based targets placed near a cathode of plasma-focus facility

The paper presents measuring techniques and results of experiments performed within the PF-1000 PlasmaFocus facility in order to investigate the interaction of high-energy deuteron beams (of ED >100 keV) and deuterium plasma streams (of vstr ≥ 10⁷ cm/s) with carbon-based materials, designed for the first wall of a future thermonuclear reactor of the ICF or MCF type. Particular attention was paid to the verification of diagnostic techniques, which might be used for time- and space-resolved studies of the interaction of ion- and plasmastreams with the targets placed near the cathode outlet inside the experimental device.У роботі описані вимірювальна техніка і результати експериментів, проведених на плазмовому фокусі PF-1000, спрямованих на вивчення взаємодії высокоенергетичних пучків дейтронів (ED >100 кэВ) і потоків водневої плазми (vstr ≥ 10⁷ см/с) з матеріалами на основі вуглецю, розробленими для використання в ролі першої стінки майбутнього термоядерного реактора на основі інерціального або магнітного утримання. Особлива увага була приділена перевірці працездатності діагностичного устаткування, використовуваного для дослідження з тимчасовим і просторовим дозволом взаємодії іонних і плазмових потоків з мішенями, розташованими поблизу торця катода експериментальної установки.В работе описаны измерительная техника и результаты экспериментов, проведенных на плазменном фокусе PF- 1000, направленных на изучение взаимодействия высокоэнергетичных пучков дейтронов (ED >100 кэВ) и потоков водородной плазмы (vstr ≥ 10⁷ cм/с) с материалами на основе углерода, разработанными для использования в качестве первой стенки будущего термоядерного реактора, на основе инерциального или магнитного удержания. Особое внимание было уделено проверке работоспособности диагностического оборудования, используемого для исследования с временным и пространственным разрешением взаимодействия ионных и плазменных потоков с мишенями, расположенными вблизи торца катода экспериментальной установки

On tuning mechanisms of DPF devices

A global instability theory of pinching plasmas allows us to justify the well-known empirical facts of the use of a mismatched dense plasma focus (DPF) and heavy inert gas admixtures. We assume that an instability of tangential discontinuity is responsible for the instability of a current-carrying plasma column. To inhibit development of a tangential discontinuity in a plasma focus, an array of insulator fibers or metallic wires placed on the anode near the axis of a discharge camera can be used