ВЛИЯНИЕ ВНЕШНИХ УСЛОВИЙ НА ХАОС В ОБЪЕМНЫХ ЛАЗЕРАХ НА СВОБОДНЫХ ЭЛЕКТРОНАХ

The study of chaotic dynamics in the volume free electron laser (VFEL) under the influence of external incident on the VFEL grid resonator electromagnetic waves is proposed. The possibility of changes in the type and magnitude of the amplitude of the dynamic solutions, as well as the suppression of spurious modes in VFEL is demonstrated.Проведено исследование хаотической динамики в объемном лазере на свободных электронах (ОЛСЭ) под влиянием внешних падающих на сеточный резонатор ОЛСЭ электромагнитных волн. Показана возможность изменения типа и величины амплитуды динамического решения, а также подавления паразитных модв ОЛСЭ

Информационная система учета и контроля ядерного материала

A brief description of information system for nuclear material accounting developed for the national regulator in the field of nuclear and radiation safety - the Department for Nuclear and Radiation Safety of the Ministry of Emergency Situations of the Republic of Belarus (Gosatomnadzor) is given. The information system is a part of the Intellectual information system of a Gosatomnadzor employee to ensure control (supervision) in the field of nuclear and radiation safety. It is developed on the basis of free software. The system has been implemented in Gosatomnadzor and at present in the Republic of Belarus all nuclear material accounting with reporting to the IAEA is carried out with its help. The system, in full compliance with the IAEA requirements, provides automatic generation with all the necessary calculations based on the input data of the following reporting documents: physical inventory listing, inventory change report, material balance report, textual report, General Ledger. All reports are fully consistent each with other. An efficient mechanism has been developed for importing and exporting data from / to the system according to formats of fixed and labelled Code 10 required by the IAEA. All logs of the system describing reports contain a field “IAEA approved” (yes / no). If it set to “yes”, they are closed for editing and correction. A special tool has been developed for making adjustments to these documents in accordance with the IAEA rules. The system contains fully completed reference books (small journals referenced by all major journals in the database) with the necessary reference data in accordance with Code 10. The information system meets all the IAEA requirements for such systems of national regulators in the field of accounting, control and supervision of nuclear material. It can be easily translated into other languages and adapted for the needs of accounting and control of nuclear material in operating organizations.Дается краткое описание информационной системы учета ядерного материала, разработанной для национального регулятора в области ядерной и радиационной безопасности – Департамента по ядерной и радиационной безопасности Министерства по чрезвычайным ситуациям Республики Беларусь (Госатомнадзор). Информационная система является частью Интеллектуальной информационной системы сотрудника Госатомнадзора для обеспечения контроля (надзора) в области ядерной и радиационной безопасности, разработанной на основе свободного программного обеспечения. Система внедрена в Госатомнадзоре, и в настоящее время в Республике Беларусь весь учет ядерного материала с отчетностью перед МАГАТЭ ведется с ее помощью. Система в полном соответствии с требованиями МАГАТЭ обеспечивает автоматическую генерацию со всеми необходимыми расчетами на основании вводимых данных следующих отчетных документов: отчета о фактически наличном количестве материала; отчета об изменениях инвентарного количества материала; материально-балансового отчета; текстового отчета; главного журнала учета (General Ledger). Все отчеты полностью согласованы между собой. Разработан эффективный механизм импорта и экспорта данных из / в систему по требуемым МАГАТЭ форматам фиксированного и маркированного Кода 10. Все журналы системы, описывающие отчеты, содержат поле «Утвержден МАГАТЭ» (да / нет). При выборе значения «да» они закрываются для редактирования и корректировки. Разработан специальный инструмент внесения корректировок в данные документы в соответствии с правилами МАГАТЭ. Система содержит полностью заполненные справочники (небольшие журналы, на которые ссылаются все основные журналы базы данных) с необходимыми справочными данными в соответствии с типовым Кодом 10. Информационная система удовлетворяет всем требованиям МАГАТЭ для таких систем национальных регуляторов в области учета, контроля и надзора за ядерным материалом, может быть легко переведена на другие языки и адаптирована под нужды учета и контроля ядерного материала в эксплуатирующих организациях

Progress from ASDEX Upgrade experiments in preparing the physics basis of ITER operation and DEMO scenario development

An overview of recent results obtained at the tokamak ASDEX Upgrade (AUG) is given. A work flow for predictive profile modelling of AUG discharges was established which is able to reproduce experimental H-mode plasma profiles based on engineering parameters only. In the plasma center, theoretical predictions on plasma current redistribution by a dynamo effect were confirmed experimentally. For core transport, the stabilizing effect of fast ion distributions on turbulent transport is shown to be important to explain the core isotope effect and improves the description of hollow low-Z impurity profiles. The L-H power threshold of hydrogen plasmas is not affected by small helium admixtures and it increases continuously from the deuterium to the hydrogen level when the hydrogen concentration is raised from 0 to 100%. One focus of recent campaigns was the search for a fusion relevant integrated plasma scenario without large edge localised modes (ELMs). Results from six different ELM-free confinement regimes are compared with respect to reactor relevance: ELM suppression by magnetic perturbation coils could be attributed to toroidally asymmetric turbulent fluctuations in the vicinity of the separatrix. Stable improved confinement mode plasma phases with a detached inner divertor were obtained using a feedback control of the plasma β. The enhanced D α H-mode regime was extended to higher heating power by feedback controlled radiative cooling with argon. The quasi-coherent exhaust regime was developed into an integrated scenario at high heating power and energy confinement, with a detached divertor and without large ELMs. Small ELMs close to the separatrix lead to peeling-ballooning stability and quasi continuous power exhaust. Helium beam density fluctuation measurements confirm that transport close to the separatrix is important to achieve the different ELM-free regimes. Based on separatrix plasma parameters and interchange-drift-Alfvén turbulence, an analytic model was derived that reproduces the experimentally found important operational boundaries of the density limit and between L- and H-mode confinement. Feedback control for the X-point radiator (XPR) position was established as an important element for divertor detachment control. Stable and detached ELM-free phases with H-mode confinement quality were obtained when the XPR was moved 10 cm above the X-point. Investigations of the plasma in the future flexible snow-flake divertor of AUG by means of first SOLPS-ITER simulations with drifts activated predict beneficial detachment properties and the activation of an additional strike point by the drifts

Overview of physics studies on ASDEX Upgrade

The ASDEX Upgrade (AUG) programme, jointly run with the EUROfusion MST1 task force, continues to significantly enhance the physics base of ITER and DEMO. Here, the full tungsten wall is a key asset for extrapolating to future devices. The high overall heating power, flexible heating mix and comprehensive diagnostic set allows studies ranging from mimicking the scrape-off-layer and divertor conditions of ITER and DEMO at high density to fully non-inductive operation (q 95 = 5.5, ) at low density. Higher installed electron cyclotron resonance heating power 6 MW, new diagnostics and improved analysis techniques have further enhanced the capabilities of AUG. Stable high-density H-modes with MW m-1 with fully detached strike-points have been demonstrated. The ballooning instability close to the separatrix has been identified as a potential cause leading to the H-mode density limit and is also found to play an important role for the access to small edge-localized modes (ELMs). Density limit disruptions have been successfully avoided using a path-oriented approach to disruption handling and progress has been made in understanding the dissipation and avoidance of runaway electron beams. ELM suppression with resonant magnetic perturbations is now routinely achieved reaching transiently . This gives new insight into the field penetration physics, in particular with respect to plasma flows. Modelling agrees well with plasma response measurements and a helically localised ballooning structure observed prior to the ELM is evidence for the changed edge stability due to the magnetic perturbations. The impact of 3D perturbations on heat load patterns and fast-ion losses have been further elaborated. Progress has also been made in understanding the ELM cycle itself. Here, new fast measurements of and E r allow for inter ELM transport analysis confirming that E r is dominated by the diamagnetic term even for fast timescales. New analysis techniques allow detailed comparison of the ELM crash and are in good agreement with nonlinear MHD modelling. The observation of accelerated ions during the ELM crash can be seen as evidence for the reconnection during the ELM. As type-I ELMs (even mitigated) are likely not a viable operational regime in DEMO studies of 'natural' no ELM regimes have been extended. Stable I-modes up to have been characterised using -feedback. Core physics has been advanced by more detailed characterisation of the turbulence with new measurements such as the eddy tilt angle - measured for the first time - or the cross-phase angle of and fluctuations. These new data put strong constraints on gyro-kinetic turbulence modelling. In addition, carefully executed studies in different main species (H, D and He) and with different heating mixes highlight the importance of the collisional energy exchange for interpreting energy confinement. A new regime with a hollow profile now gives access to regimes mimicking aspects of burning plasma conditions and lead to nonlinear interactions of energetic particle modes despite the sub-Alfvénic beam energy. This will help to validate the fast-ion codes for predicting ITER and DEMO