Two neutral beam injectors (NBIs) were installed on the COMPASS tokamak as a main upgrade after its move from the UK to Prague. The thesis deals with general experimental specifications of additionally heated plasmas by the NBI under the wide range of conditions on the COMPASS tokamak. The geometrical parameters of the beams are determined from the spectro- scopic measurements. Consequently, the NBI power passing through the narrow duct connecting NBI and tokamak chamber is investigated. The passing fraction of the NBI power is confirmed by the power balance analysis, which provides information about the delivered power into the plasma based on the plasma parameters. Once the delivered power is well known a description of beams interaction with plasma via global parameters such as the plasma temperatures, the plasma density, the energy confinement time and neutron yield is given. It is shown, that the NBIs heat mostly ions, which can reach ∼ 1 keV in the plasma core. Moreover, the impact of the fast ions presence on the commonly observed MHD activities, the sawtooth instability and the edge localized modes (ELMs), is discussed and compared with results from other tokamaks. The sawtooth period is prolonged by the influence of the NBI from 2 ms up to 4.5 ms. The knowledge of the NBI passing power into...

Orientador: Munemasa Machida / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Física Gleb Wataghin / Made available in DSpace on 2018-08-17T22:07:56Z (GMT). No. of bitstreams: 1 Arsioli_BrunoSversut_M.pdf: 7832170 bytes, checksum: 4c771ec7e75b395d3088ed5f46d63820 (MD5) Previous issue date: 2011 / Resumo: O desenvolvimento deste trabalho ocorreu em duas frentes distintas relacionadas à grande área de pesquisa: Fusão Termonuclear Controlada em dispositivos do tipo tokamak. A primeira fase abordou estudos de espectroscopia, tendo como principal motivação o aprimoramento dos métodos de medida e tratamento de dados na área de diagnósticos de plasmas quentes. Os trabalhos consistem no diagnóstico por espectroscopia na região do ultravioleta do vácuo (UVV), realizados nos tokamaks TCABr-USP (Lab. Plasmas USP) e Nova-Unicamp (Lab. de Plasmas IFGW-UNICAMP), e concentraram-se na utilização do detector multicanal do tipo MCP-CCD, acoplado a um espectr ômetro de grade simples McPherson-225 operando na região espectral de 500 a 3200 °A, buscando ordens superiores de difração para o cálculo da temperatura iônica (Ti) via medida do alargamento Doppler (??D). A ideia para o cálculo da Ti é a utilização da relação entre os sinais de ordens superiores de difração (OSD), a fim de reduzir a influência do alargamento instrumental no cálculo do parâmetro ??D, do qual depende a medida de Ti. Também foram coletados dados com fotomultiplicadora, explorando a possibilidade de registrar a evolução temporal (com resolução de 1ms) da intensidade das emissões de algumas das principais impurezas presentes no plasma. Numa segunda fase, realizaram-se estudos do aquecimento do plasma por meio de injeção de partícula neutras (IPN) de alta energia (42-93 keV) no tokamak ASDEX Upgrade (Max-Planck-Institut fur Plasmaphysik; Garching- Alemanha). Tal atividade foi desenvolvida dentro do programa de mestrado em fusão nuclear da União Europeia, ErasmusMundus Fusion-EP, que esteve sob orientação de Dr. Ryter Fran¸cois, e supervisão de Prof. Dr. Stroth Ulrich (Universitat Stuttgart) e Jose Ramon Martin Solis (Universidad Carlos III de Madrid). O tokamak ASDEX Upgrade geralmente opera com plasma de Deutério, sendo a Injeção de Partículas Neutras de Deutério (IPN-D) a principal forma de aquecimento. Para este esquema de operação usual, os perfis de deposição de energia do feixe, ao longo da direção radial, foram extensivamente documentados por meio de cálculos com o código computacional FAFNER. Formulas gerais para os principais parâmetros relacionados à potência depositada e confinamento dos íons rápidos foram desenvolvidas e são rotineiramente utilizadas. No entanto, plasmas de Hélio aquecido por injeção de hidrogênio (IPN-H) e deutério (IPN-D), ocasionalmente são utilizados no ASDEX Upgrade. Uma das motivações para o estudo desse cenário reside na possibilidade de operação do ITER com plasma de hélio, ao menos na fase inicial de baixa ativação. Tal escolha permitiria comissionar os sistemas de controle e diagnóstico sem a necessidade de ativação radioativa das estruturas que compõe o reator, já que as taxas de fusão nuclear seriam mínimas. Até então, a documentação da deposição de potência por IPN em plasma de hélio no tokamak ASDEX Upgrade ainda não havia sido realizada. O objetivo do presente trabalho é a documentação das propriedades de aquecimento por IPN-H e IPN-D em plasma de hélio, utilizando o código FAFNER, sendo de grande interesse viabilizar o uso de uma nova base de dados chamada ADAS. Esta, contém tabelas com coeficientes de atenuação ?s??i adicionais, permitindo levar em conta a presença de átomos excitados no feixe de partículas neutras interagindo com o plasma, o que tem impacto direto sobre a deposição de potência por IPN / Abstract: The development of the present work has happened in two frames strictly related with the research on Thermonuclear Fusion in tokamaks. The first phase was dedicated to studies with spectroscopy, which had as main motivation the development of measurement and data treatment methods concerning hot plasmas diagnostic. Basically, it consisted in UV spectroscopic measurements carried on at TCABr-USP (Lab. Plasmas USP - São Paulo, Brazil) and Nova-Unicamp (Lab. de Plasmas do IFGW-UNICAMP - Campinas, Brazil) tokamaks. The activities were concentrated on the use of a multichannel detector MCP-CCD type, coupled with a single grating spectrometer McPherson-225, allowing VUV spectroscopy at the 500 - 3200°A spectra. The main objective was to look for signals of high diffraction orders aiming to calculate ion temperature via Doppler broadening (??D). The idea for getting precise Ti measurements was to make a relation between high diffraction order (HDO) signals to reduce the influence of the instrumental broadening, which has been accomplished with success. A series of data with photomultiplier was collected at the UV region, exploring the possibility of getting the time evolution of the emission intensity of the main impurities from the plasma. All work carried out on spectroscopy in small size experiments like NOVA tokamak are of great importance. In a second phase, studies related with plasma heating by Neutral Beam Injection (NBI) 42-93 keV were carried out in ASDEX Upgrade tokamak (at Max-Planck-Institut fur Plasmaphysik; Garching-Germany). This activity was developed in the frame of European Union Master Program, ErasmusMundus Fusion-EP, oriented by Dr. Ryter Fran¸cois, and supervised by Prof. Dr. Stroth Ulrich (Universitat Stuttgart) and Prof. Dr.Jose Ramon Martin Solis (Universidad Carlos III de Madrid). The ASDEX Upgrade tokamak is generally operated in deuterium plasma with deuterium Neutral Beam Injection (D-NBI) as main heating. For this usual operation scheme, the heating power deposition has been extensively documented by calculations with the code FAFNER. General fit formulas for the most important parameters related to the power deposition and fast ion content have been developed and are routinely used. However, helium plasmas heated by H-NBI or D-NBI are also occasionally performed in ASDEX Upgrade. One of the motivation for using helium resides in the fact that the low activation phase of ITER might be, at least partly, carried out in helium plasmas. So far, the documentation of the NBI deposition in helium plasmas in ASDEX Upgrade has not been made. The aim of the present work was to document the heating properties of H-NBI and D-NBI for helium plasmas, using the FAFNER code, being of great interest to get FAFNER running with new libraries (ADAS) for the calculation of the stopping rate coefficients ?s??i, allowing to evaluate the influence of excited atoms in the neutral beam. The final goal was to provide a reliable estimate of the main quantities linked to NBI heating in a set of helium discharges, in particular absorbed power, fast ion losses and fast ion energy content / Mestrado / Física de Plasmas e Descargas Elétricas / Mestre em Física

This thesis concerns heating and current drive in tokamak plasmas using the fast magnetosonic wave in the ion cyclotron range of frequencies. Fast wave heating is a versatile heating method for thermonuclear fusion plasmas and can provide both ion and electron heating and non-inductive current drive. Predicting and interpreting realistic heating scenarios is however difficult due to the coupled evolution of the cyclotron resonant ion velocity distributions and the wave field. The SELFO code, which solves the coupled wave equation and Fokker-Planck equation for cyclotron resonant ion species in a self-consistent manner, has been upgraded to allow the study of more advanced fast wave heating and current drive scenarios in present day experiments and in preparation for the ITER tokamak. Theoretical and experimental studies related to fast wave heating and current drive with emphasis on fast ion effects are presented. Analysis of minority ion cyclotron current drive in ITER indicates that the use of a hydrogen minority rather than the proposed helium-3 minority results in substantially more efficient current drive. The parasitic losses of power to fusion born alpha particles and beam injected ions are concluded to be acceptably low. Experiments performed at the JET tokamak on polychromatic ion cyclotron resonance heating and on fast wave electron current drive are presented and analysed. Polychromatic heating is demonstrated to increase the bulk plasma ion to electron heating ratio, in line with theoretical expectations, but the fast wave electron current drive is found to be severely degraded by parasitic power losses outside of the plasma. A theoretical analysis of parasitic power losses at radio frequency antennas indicates that the losses can be significantly increased in scenarios with low wave damping and with narrow antenna spectra, such as in electron current drive scenarios. / QC 20100506