E. Rachlew | KTH Royal Institute of Technology (original) (raw)

Papers by E. Rachlew

Research paper thumbnail of Impact of ICRF on the scrape-off layer and on plasma wall interactions: From present experiments to fusion reactor

Nuclear Materials and Energy, 2019

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Research paper thumbnail of ELMs and Strike Point Jumps . ELMs and Strike Point Jumps

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Research paper thumbnail of Temperature

spectroscopic method to determine changes in the electron

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Research paper thumbnail of Injection o

ABSTRACT. Injection of Lower Hybrid Heating and Current Drive (LHCD) into the current ramp-up pha... more ABSTRACT. Injection of Lower Hybrid Heating and Current Drive (LHCD) into the current ramp-up phase of JET discharges can produce extremely reversed q-profiles characterized by a core region of near zero current density (within Motional Stark Effect diagnostic measurement errors). Non-inductive, off-axis co-current drive induces a back electromotive force inside the non-inductive current radius that drives a negative current in the plasma core. The core current density does not go negative, although current diffusion calculations indicate that there is sufficient LHCD to cause this. The clamping of the core current density near zero is consistent with n=0 reconnection events redistributing the core current soon after it goes negative. This is seen in reduced MHD simulations and in nonlinear resistive MHD simulations which predict that these

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Research paper thumbnail of IAEA-CN-116/EX/P1-3 ELMs, strike point jumps and SOL currents

Abstract. Plasma equilibria before and after ELMs in JET are investigated. ELMs could be associat... more Abstract. Plasma equilibria before and after ELMs in JET are investigated. ELMs could be associated with fragile equilibria and separatrix instabilities: previously closed field lines would open up, releasing plasma current and leading to the formation of a new, smaller separatrix. This model could explain experimental observations of sudden jumps and shifts in strike point positions. Novel instability mechanisms are discussed to explain the large transient jumps observed in the strike point position: positive X-point instability, due to positive toroidal current density at the X-point and diamagnetic instability, due to negative inboard toroidal current density. 1. Theoretical background: plasma equilibrium before the ELM Plasma force balance in a magnetic confinement device with closed field lines is given by the equation: j B × =∇pGG (1) where j is the total current density, B the magnetic field and p the pressure. In tokamak equilibrium, the pressure is usually considered as a m...

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Research paper thumbnail of Fragmentation of imidazole, pyrimidine and purine induced by core ionization: Significance of small-scale chemical environment

Journal of Photochemistry and Photobiology A: Chemistry, 2018

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Research paper thumbnail of Dimensionless scalings of confinement, heat transport and pedestal stability in JET-ILW and comparison with JET-C

Plasma Physics and Controlled Fusion, 2016

Three dimensionless scans in the normalized Larmor radius rho*, normalized collisionality nu* and... more Three dimensionless scans in the normalized Larmor radius rho*, normalized collisionality nu* and normalized plasma pressure beta have been performed in JET with the ITER-like wall (JET-ILW). The n ...

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Research paper thumbnail of Molecular dynamics of photodissociation: towards more complex systems

Journal of Physics: Conference Series, 2015

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Research paper thumbnail of Abe, M., T. Yanai, T. Nakajima and K. Hirao, A four-index transformation in Dirac’s four-component relativistic theory 388 (2004) 68 Abusara, Z., TS Sorensen and N. Moazzen-Ahmadi, Infrared laser spectroscopy of CCO: the m3 band of the ea1D electronic state and 3m3–2m3 band of the ground electron...

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Research paper thumbnail of First observation of photoelectron spectra emitted in the photoionization of a singly charged-ion beam with synchrotron radiation

Physical Review Letters, 1991

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Research paper thumbnail of Overview of JET results

Nuclear Fusion, 2009

Since the last IAEA conference, the scientific programme of JET has focused on the qualification ... more Since the last IAEA conference, the scientific programme of JET has focused on the qualification of the integrated operating scenarios for ITER and on physics issues essential for the consolidation of design choices and the efficient exploitation of ITER. Particular attention has been given to the characterization of the edge plasma, pedestal energy and edge localized modes (ELMs), and their

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Research paper thumbnail of Photoionization processes in NO in the threshold region

Chemical Physics Letters, 1997

ABSTRACT The photoion excitation spectrum of NO has been measured in the 9.26–13.8 eV region usin... more ABSTRACT The photoion excitation spectrum of NO has been measured in the 9.26–13.8 eV region using synchroton light and the isotopic targets 14N16O, 15N16O and 15N18O. The resulting complex spectra have been interpreted using ab initio results based on many-body theory. The ab initio predictions suggest that the structure follows from autoionizations of four repulsive valence states of 2Σ symmetry and interactions between an attractive 2δ valence state and Rydberg series converging to the NO+ ground state.

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Research paper thumbnail of Lyman and Balmer emission following core excitations in methane and ammonia molecules

Journal of Physics B: Atomic, Molecular and Optical Physics, 2007

Page 1. Lyman and Balmer emission following core excitations in methane and ammonia molecules Thi... more Page 1. Lyman and Balmer emission following core excitations in methane and ammonia molecules This article has been downloaded from IOPscience. Please scroll down to see the full text article. 2007 J. Phys. B: At. Mol. Opt. Phys. 40 1489 ...

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Research paper thumbnail of Oxygen impurity profile studies in the EXTRAP T2R reversed field pinch

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Research paper thumbnail of Overview of the JET results in support to ITER

Nuclear Fusion, 2017

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Research paper thumbnail of Temperature

spectroscopic method to determine changes in the electron

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Research paper thumbnail of 1 EXS / P 305 Observation of Confined Current Structures in JET High Temperature Pedestals and Transient ELM Suppression

We report the identification of a localized current structure inside the JET plasma. It is a fiel... more We report the identification of a localized current structure inside the JET plasma. It is a field aligned closed helical ribbon, carrying current in the same direction as the background current profile (co-current), rotating toroidally with the ion velocity (co-rotating). It appears to be located at an n=1 rational surface at a flat spot in the plasma pressure profile, at the top of the pedestal, and not in the gradient region. The current structure appears spontaneously in low density, high pedestal temperature, high rotation plasmas, and can last up to 1. s, a time comparable to a local resistive time. It considerably delays the appearance of the first ELM, and regulates transport across the separatrix.

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Research paper thumbnail of Effect of disorder on the unoccupied states of germanium telluride

Journal of Physics C: Solid State Physics, 1975

The Te L1 and L3 X-ray absorption spectra for some GeTe compounds in amorphous and crystalline fo... more The Te L1 and L3 X-ray absorption spectra for some GeTe compounds in amorphous and crystalline form are presented. No shifts of the Te core levels 2s and 2p3/2 were observed between the amorphous and crystalline phases or between the element and the compounds. The L3 but not the L1 spectra showed changes in structure about 5-10 eV above the Fermi level when amorphous GeTe crystallized. This is attributed to states about 6 eV above EF and it is concluded that these largely d-like states are more affected by the order-disorder transformation than the lower sp bands.

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Research paper thumbnail of Sustainable energy supply and consumption by 2050 and outlook towards the end of the century: Possible scientific breakthroughs

Ambio, 2016

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Research paper thumbnail of Ionization-site effects on the photofragmentation of chloro- and bromoacetic acid molecules

Physical Review A, 2015

Fragmentation of gas-phase chloro-and bromoacetic acid samples, particularly its dependency on th... more Fragmentation of gas-phase chloro-and bromoacetic acid samples, particularly its dependency on the atomic site of the initial core ionization, was studied in photoelectron-photoion-photoion coincidence (PEPIPICO) measurements. The fragmentation was investigated after ionizing carbon 1s and bromine 3d or chlorine 2p core orbitals. It was observed that the samples had many similar fragmentation pathways and that their relative weights depended strongly on the initial ionization site. Additional Auger PEPIPICO measurements revealed a clear dependence of fragment pair intensities on the kinetic energy of the emitted Auger electrons. The modeled and measured Auger electron spectra indicated that the average internal energy of the molecule was larger following the carbon 1s core-hole decay than after the decay of the halogen core hole. This difference in the internal energies was found to be the source of the site-dependent photofragmentation behavior.

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Research paper thumbnail of Impact of ICRF on the scrape-off layer and on plasma wall interactions: From present experiments to fusion reactor

Nuclear Materials and Energy, 2019

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Research paper thumbnail of ELMs and Strike Point Jumps . ELMs and Strike Point Jumps

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Temperature

spectroscopic method to determine changes in the electron

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Injection o

ABSTRACT. Injection of Lower Hybrid Heating and Current Drive (LHCD) into the current ramp-up pha... more ABSTRACT. Injection of Lower Hybrid Heating and Current Drive (LHCD) into the current ramp-up phase of JET discharges can produce extremely reversed q-profiles characterized by a core region of near zero current density (within Motional Stark Effect diagnostic measurement errors). Non-inductive, off-axis co-current drive induces a back electromotive force inside the non-inductive current radius that drives a negative current in the plasma core. The core current density does not go negative, although current diffusion calculations indicate that there is sufficient LHCD to cause this. The clamping of the core current density near zero is consistent with n=0 reconnection events redistributing the core current soon after it goes negative. This is seen in reduced MHD simulations and in nonlinear resistive MHD simulations which predict that these

Bookmarks Related papers MentionsView impact

Research paper thumbnail of IAEA-CN-116/EX/P1-3 ELMs, strike point jumps and SOL currents

Abstract. Plasma equilibria before and after ELMs in JET are investigated. ELMs could be associat... more Abstract. Plasma equilibria before and after ELMs in JET are investigated. ELMs could be associated with fragile equilibria and separatrix instabilities: previously closed field lines would open up, releasing plasma current and leading to the formation of a new, smaller separatrix. This model could explain experimental observations of sudden jumps and shifts in strike point positions. Novel instability mechanisms are discussed to explain the large transient jumps observed in the strike point position: positive X-point instability, due to positive toroidal current density at the X-point and diamagnetic instability, due to negative inboard toroidal current density. 1. Theoretical background: plasma equilibrium before the ELM Plasma force balance in a magnetic confinement device with closed field lines is given by the equation: j B × =∇pGG (1) where j is the total current density, B the magnetic field and p the pressure. In tokamak equilibrium, the pressure is usually considered as a m...

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Research paper thumbnail of Fragmentation of imidazole, pyrimidine and purine induced by core ionization: Significance of small-scale chemical environment

Journal of Photochemistry and Photobiology A: Chemistry, 2018

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Dimensionless scalings of confinement, heat transport and pedestal stability in JET-ILW and comparison with JET-C

Plasma Physics and Controlled Fusion, 2016

Three dimensionless scans in the normalized Larmor radius rho*, normalized collisionality nu* and... more Three dimensionless scans in the normalized Larmor radius rho*, normalized collisionality nu* and normalized plasma pressure beta have been performed in JET with the ITER-like wall (JET-ILW). The n ...

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Molecular dynamics of photodissociation: towards more complex systems

Journal of Physics: Conference Series, 2015

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Abe, M., T. Yanai, T. Nakajima and K. Hirao, A four-index transformation in Dirac’s four-component relativistic theory 388 (2004) 68 Abusara, Z., TS Sorensen and N. Moazzen-Ahmadi, Infrared laser spectroscopy of CCO: the m3 band of the ea1D electronic state and 3m3–2m3 band of the ground electron...

Bookmarks Related papers MentionsView impact

Research paper thumbnail of First observation of photoelectron spectra emitted in the photoionization of a singly charged-ion beam with synchrotron radiation

Physical Review Letters, 1991

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Overview of JET results

Nuclear Fusion, 2009

Since the last IAEA conference, the scientific programme of JET has focused on the qualification ... more Since the last IAEA conference, the scientific programme of JET has focused on the qualification of the integrated operating scenarios for ITER and on physics issues essential for the consolidation of design choices and the efficient exploitation of ITER. Particular attention has been given to the characterization of the edge plasma, pedestal energy and edge localized modes (ELMs), and their

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Photoionization processes in NO in the threshold region

Chemical Physics Letters, 1997

ABSTRACT The photoion excitation spectrum of NO has been measured in the 9.26–13.8 eV region usin... more ABSTRACT The photoion excitation spectrum of NO has been measured in the 9.26–13.8 eV region using synchroton light and the isotopic targets 14N16O, 15N16O and 15N18O. The resulting complex spectra have been interpreted using ab initio results based on many-body theory. The ab initio predictions suggest that the structure follows from autoionizations of four repulsive valence states of 2Σ symmetry and interactions between an attractive 2δ valence state and Rydberg series converging to the NO+ ground state.

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Research paper thumbnail of Lyman and Balmer emission following core excitations in methane and ammonia molecules

Journal of Physics B: Atomic, Molecular and Optical Physics, 2007

Page 1. Lyman and Balmer emission following core excitations in methane and ammonia molecules Thi... more Page 1. Lyman and Balmer emission following core excitations in methane and ammonia molecules This article has been downloaded from IOPscience. Please scroll down to see the full text article. 2007 J. Phys. B: At. Mol. Opt. Phys. 40 1489 ...

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Research paper thumbnail of Oxygen impurity profile studies in the EXTRAP T2R reversed field pinch

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Overview of the JET results in support to ITER

Nuclear Fusion, 2017

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Temperature

spectroscopic method to determine changes in the electron

Bookmarks Related papers MentionsView impact

Research paper thumbnail of 1 EXS / P 305 Observation of Confined Current Structures in JET High Temperature Pedestals and Transient ELM Suppression

We report the identification of a localized current structure inside the JET plasma. It is a fiel... more We report the identification of a localized current structure inside the JET plasma. It is a field aligned closed helical ribbon, carrying current in the same direction as the background current profile (co-current), rotating toroidally with the ion velocity (co-rotating). It appears to be located at an n=1 rational surface at a flat spot in the plasma pressure profile, at the top of the pedestal, and not in the gradient region. The current structure appears spontaneously in low density, high pedestal temperature, high rotation plasmas, and can last up to 1. s, a time comparable to a local resistive time. It considerably delays the appearance of the first ELM, and regulates transport across the separatrix.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Effect of disorder on the unoccupied states of germanium telluride

Journal of Physics C: Solid State Physics, 1975

The Te L1 and L3 X-ray absorption spectra for some GeTe compounds in amorphous and crystalline fo... more The Te L1 and L3 X-ray absorption spectra for some GeTe compounds in amorphous and crystalline form are presented. No shifts of the Te core levels 2s and 2p3/2 were observed between the amorphous and crystalline phases or between the element and the compounds. The L3 but not the L1 spectra showed changes in structure about 5-10 eV above the Fermi level when amorphous GeTe crystallized. This is attributed to states about 6 eV above EF and it is concluded that these largely d-like states are more affected by the order-disorder transformation than the lower sp bands.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Sustainable energy supply and consumption by 2050 and outlook towards the end of the century: Possible scientific breakthroughs

Ambio, 2016

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Ionization-site effects on the photofragmentation of chloro- and bromoacetic acid molecules

Physical Review A, 2015

Fragmentation of gas-phase chloro-and bromoacetic acid samples, particularly its dependency on th... more Fragmentation of gas-phase chloro-and bromoacetic acid samples, particularly its dependency on the atomic site of the initial core ionization, was studied in photoelectron-photoion-photoion coincidence (PEPIPICO) measurements. The fragmentation was investigated after ionizing carbon 1s and bromine 3d or chlorine 2p core orbitals. It was observed that the samples had many similar fragmentation pathways and that their relative weights depended strongly on the initial ionization site. Additional Auger PEPIPICO measurements revealed a clear dependence of fragment pair intensities on the kinetic energy of the emitted Auger electrons. The modeled and measured Auger electron spectra indicated that the average internal energy of the molecule was larger following the carbon 1s core-hole decay than after the decay of the halogen core hole. This difference in the internal energies was found to be the source of the site-dependent photofragmentation behavior.

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