Studium rekombinace H3+ ve vybranych kvantových stavech

Název práce: Studium rekombinace H3 + ve vybranych kvantových stavech Autor: Jozef Varju Katedra / Ústav: Katedry fyziky povrchů a plazmatu Vedoucí doktorské práce: Prof. RNDr. Juraj Glosík, DrSc., Katedry fyziky povrchů a plazmatu Abstrakt: V tejto práci su prezentované merania effektívnej rýchlostnej konšntanty rekombinacie v H3 + dominovanej plazme a ovladanej rekombináciou pri 77 K a 145 K. Populácia para-H3 + v študovanej plazme bola menená použitím H2 s obohatenou populaciou para stavov ako reaktantu popri normálnom H2. Časovo rozlíšená CRDS v blízkej infračervenej oblasti bola použita na in-situ meranie vývoja hustoty dvoch najnižších rotačných stavov H3 + . Merania pri rôzných pomeroch para ku orto H3 + , pri inač identických podmienkach, umožnili extrapolovanie effektivnej rýchlostnej konštanty rekombinácie čistého para-H3 + a orto-H3 + . S nameraných závislosti na hustote nosného plynu boli učené hodnoty rýchlostnej konštanty rekombinácie binárneho a ternárneho kanálu pre para-H3 + a ortho-H3 + . Klíčová slova: rekombinace, spektroskopie, H3 + , para H2Title: Study of H3 + recombination in selected quantum states Author: Jozef Varju Department : Department of Surface and Plasma Science Supervisor of the doctoral thesis: Prof. RNDr. Juraj Glosík, DrSc., Department of Surface and Plasma Science Abstract: In this work measurement of the effective recombination rate coefficient of H3 + dominated and recombination governed afterglow plasma at 77 K and 145 K are presented. Population of para-H3 + in the studied plasma has been varied by using para enriched H2 as a precursor along with normal H2. Time resolved NIR-CRDS was used to in-situ measure the number density evolution of the two lowest rotational states of H3 + . Measurements at different para to ortho H3 + ratios, at otherwise identical conditions, allowed for extrapolation of the effective recombination rate coefficient of pure para-H3 + and ortho-H3 + . From measured dependences on the buffer gas densities the values of the recombination rate coefficients for the binary and ternary channel are determined of para-H3 + and ortho-H3 + . Keywords: recombination, spectroscopy, H3 + , para H2Department of Surface and Plasma ScienceKatedra fyziky povrchů a plazmatuFaculty of Mathematics and PhysicsMatematicko-fyzikální fakult

Study of H3+ recombination in selected quantum states

Title: Study of H3 + recombination in selected quantum states Author: Jozef Varju Department : Department of Surface and Plasma Science Supervisor of the doctoral thesis: Prof. RNDr. Juraj Glosík, DrSc., Department of Surface and Plasma Science Abstract: In this work measurement of the effective recombination rate coefficient of H3 + dominated and recombination governed afterglow plasma at 77 K and 145 K are presented. Population of para-H3 + in the studied plasma has been varied by using para enriched H2 as a precursor along with normal H2. Time resolved NIR-CRDS was used to in-situ measure the number density evolution of the two lowest rotational states of H3 + . Measurements at different para to ortho H3 + ratios, at otherwise identical conditions, allowed for extrapolation of the effective recombination rate coefficient of pure para-H3 + and ortho-H3 + . From measured dependences on the buffer gas densities the values of the recombination rate coefficients for the binary and ternary channel are determined of para-H3 + and ortho-H3 + . Keywords: recombination, spectroscopy, H3 + , para H

Rekombinace a reakce iontů v plazmatu

One of the most interesting questions in contemporary interstellar chemistry is the HCN/HNC abundance ratio observed in dense interstellar clouds. The observed ratios vary from 80:1 to 1:5 depending on the object under observation. These ratios represent a striking deviation from thermochemical equilibrium. Dissociative recombination of HCNH+ has been invoked to explain these observations. It is suggested to study details of this recombination using FALP apparatus equipped with NIR Cavity Ringdown Absorption Spectrometer (IR - CRDS). In the presented work we have developed kinetic model describing formation of HCNH+/e- plasma and consequent production of HCN and HNC. Analysed and discussed are conditions of experiment and applicability of IR - CRDS for the proposed study. To confirm our analyses the preliminary experiments were carried out using microwave discharge cell equipped with IR - CRDS. Studies of H3O+ and H2D+ ions were carried out to put together the experiment. The absorption spectra in a plasma containing He/N2/CH4 were measured in order to determine transition frequencies for study of products of recombination of CNH+ ions

Rekombinace a reakce iontů v plazmatu

One of the most interesting questions in contemporary interstellar chemistry is the HCN/HNC abundance ratio observed in dense interstellar clouds. The observed ratios vary from 80:1 to 1:5 depending on the object under observation. These ratios represent a striking deviation from thermochemical equilibrium. Dissociative recombination of HCNH+ has been invoked to explain these observations. It is suggested to study details of this recombination using FALP apparatus equipped with NIR Cavity Ringdown Absorption Spectrometer (IR - CRDS). In the presented work we have developed kinetic model describing formation of HCNH+/e- plasma and consequent production of HCN and HNC. Analysed and discussed are conditions of experiment and applicability of IR - CRDS for the proposed study. To confirm our analyses the preliminary experiments were carried out using microwave discharge cell equipped with IR - CRDS. Studies of H3O+ and H2D+ ions were carried out to put together the experiment. The absorption spectra in a plasma containing He/N2/CH4 were measured in order to determine transition frequencies for study of products of recombination of CNH+ ions

Energy composition of high-energy neutral beams on the COMPASS tokamak

The COMPASS tokamak is equipped with two identical neutral beam injectors (NBI) for additional plasma heating. They provide a beam of deuterium atoms with a power of up to ~(2 × 300) kW. We show that the neutral beam is not monoenergetic but contains several energy components. An accurate knowledge of the neutral beam power in each individual energy component is essential for a detailed description of the beam- -plasma interaction and better understanding of the NBI heating processes in the COMPASS tokamak. This paper describes the determination of individual energy components in the neutral beam from intensities of the Doppler-shifted Dα lines, which are measured by a high-resolution spectrometer viewing the neutral beam-line at the exit of NBI. Furthermore, the divergence of beamlets escaping single aperture of the last accelerating grid is deduced from the width of the Doppler-shifted lines. Recently, one of the NBI systems was modified by the removal of the Faraday copper shield from the ion source. The comparison of the beam composition and the beamlet divergence before and after this modification is also presented

Energy composition of high-energy neutral beams on the COMPASS tokamak

The COMPASS tokamak is equipped with two identical neutral beam injectors (NBI) for additional plasma heating. They provide a beam of deuterium atoms with a power of up to ~(2 × 300) kW. We show that the neutral beam is not monoenergetic but contains several energy components. An accurate knowledge of the neutral beam power in each individual energy component is essential for a detailed description of the beam- -plasma interaction and better understanding of the NBI heating processes in the COMPASS tokamak. This paper describes the determination of individual energy components in the neutral beam from intensities of the Doppler-shifted Dα lines, which are measured by a high-resolution spectrometer viewing the neutral beam-line at the exit of NBI. Furthermore, the divergence of beamlets escaping single aperture of the last accelerating grid is deduced from the width of the Doppler-shifted lines. Recently, one of the NBI systems was modified by the removal of the Faraday copper shield from the ion source. The comparison of the beam composition and the beamlet divergence before and after this modification is also presented

Positioned agents in eco-grammar systems with border markers and pure regulated grammars

summary:In this paper we follow our previous research in the field of positioned agents in the eco-grammar systems and pure grammars. We extend model of the positioned eco-grammar systems by boundary markers and we introduce bordered positioned eco-grammar systems (BPEG systems, for short) and that way we show one of the possible answers to the question stated in [9]. Namely we compare generative power of the BPEG systems with three types of pure regulated grammars with appearance checking

Oxidation of Inconel 625 superalloy upon treatment with oxygen or hydrogen plasma at high temperature

International audienc

Overview of the COMPASS results

COMPASS addressed several physical processes that may explain the behaviour of important phenomena. This paper presents results related to the main fields of COMPASS research obtained in the recent two years, including studies of turbulence, L–H transition, plasma material interaction, runaway electron, and disruption physics: • Tomographic reconstruction of the edge/SOL turbulence observed by a fast visible camera allowed to visualize turbulent structures without perturbing the plasma. • Dependence of the power threshold on the X-point height was studied and related role of radial electric field in the edge/SOL plasma was identified. • The effect of high-field-side error fields on the L–H transition was investigated in order to assess the influence of the central solenoid misalignment and the possibility to compensate these error fields by low-field-side coils. • Results of fast measurements of electron temperature during ELMs show the ELM peak values at the divertor are around 80% of the initial temperature at the pedestal. • Liquid metals were used for the first time as plasma facing material in ELMy H-mode in the tokamak divertor. Good power handling capability was observed for heat fluxes up to 12 MW m−2 and no direct droplet ejection was observed. • Partial detachment regime was achieved by impurity seeding in the divertor. The evolution of the heat flux footprint at the outer target was studied. • Runaway electrons were studied using new unique systems—impact calorimetry, carbon pellet injection technique, wide variety of magnetic perturbations. Radial feedback control was imposed on the beam. • Forces during plasma disruptions were monitored by a number of new diagnostics for vacuum vessel (VV) motion in order to contribute to the scaling laws of sideways disruption forces for ITER. • Current flows towards the divertor tiles, incl. possible short-circuiting through PFCs, were investigated during the VDE experiments. The results support ATEC model and improve understanding of disruption loads

Preliminary design of the COMPASS upgrade tokamak

COMPASS Upgrade is a new medium size, high magnetic field tokamak (R = 0.9 m, Bt = 5 T, Ip = 2 MA) currently under design in the Czech Republic. It will provide unique capabilities for addressing some of the key challenges in plasma exhaust physics, advanced confinement modes and advanced plasma configurations as well as testing new plasma facing materials and liquid metal divertor concepts. This paper contains an overview of the preliminary engineering design of the main systems of the COMPASS Upgrade tokamak (vacuum vessel, central solenoid and poloidal field coils, toroidal field coils, support structure, cryostat, cryogenic system, power supply system and machine monitoring and protection system). The description of foreseen auxiliary plasma heating systems and plasma diagnostics is also provided as well as a summary of expected plasma performance and available plasma configurations