D. Hathiramani
A5005247520- Magnetic confinement fusion research
- Atomic and Molecular Physics
- Mass Spectrometry Techniques and Applications
- Superconducting Materials and Applications
- Ion-surface interactions and analysis
- Fusion materials and technologies
- Particle accelerators and beam dynamics
- X-ray Spectroscopy and Fluorescence Analysis
- Laser-Plasma Interactions and Diagnostics
- Advancements in Solid Oxide Fuel Cells
- Fullerene Chemistry and Applications
- Electromagnetic Launch and Propulsion Technology
- Astronomical Observations and Instrumentation
- High-Temperature Coating Behaviors
- Laser-induced spectroscopy and plasma
- Ionosphere and magnetosphere dynamics
- Geomagnetism and Paleomagnetism Studies
- Particle Accelerators and Free-Electron Lasers
- Solar and Space Plasma Dynamics
- Catalytic Processes in Materials Science
- Spacecraft and Cryogenic Technologies
- Electronic and Structural Properties of Oxides
- Fuel Cells and Related Materials
- Advanced Chemical Physics Studies
- Nuclear Materials and Properties
Max Planck Institute for Plasma Physics - Greifswald
2012-2024
Max Planck Institute for Plasma Physics
2012-2021
Max Planck Society
2009-2020
Australian National University
2016
Oak Ridge National Laboratory
2016
Physikalisch-Technische Bundesanstalt
2016
University of Opole
2016
CEA Cadarache
2016
National Institute for Fusion Science
2016
Culham Science Centre
2016
Abstract Fusion energy research has in the past 40 years focused primarily on tokamak concept, but recent advances plasma theory and computational power have led to renewed interest stellarators. The largest most sophisticated stellarator world, Wendelstein 7-X (W7-X), just started operation, with aim show that earlier weaknesses of this concept been addressed successfully, intrinsic advantages persist, also at parameters approaching those a future fusion plant. Here we first physics...
The next step in the Wendelstein stellarator line is large superconducting device 7-X, currently under construction Greifswald, Germany. Steady-state operation an intrinsic feature of stellarators, and one key element 7-X mission to demonstrate steady-state plasma conditions relevant for a fusion power plant. device, on hand, requires implementation special technologies, giving rise technical challenges during design, fabrication assembly such device. On other also physics development at...
Wendelstein 7-X aims at quasi-steady state operation with up to 10 MW of heating power for 30 min. Power exhaust will be handled predominantly via actively water cooled CFC (carbon-fiber-reinforced carbon) based divertor units designed withstand loads MW/m2 locally in steady state. If local exceed this value, a risk delamination the and failure entire modules arises. Infrared endoscopes monitor all main plasma facing components are being prepared, near real time software tools under...
The Wendelstein 7-X (W7-X) optimized stellarator fusion experiment, which went into operation in 2015, has been operating since 2017 with an un-cooled modular graphite divertor. This allowed first divertor physics studies to be performed at pulse energies up 80 MJ, as opposed 4 MJ the phase, where five inboard limiters were installed instead of a This, and number other upgrades device capabilities, extension regimes higher plasma density, heating power, performance overall, e.g. setting new...
Wendelstein 7-X, a superconducting optimized stellarator built in Greifswald/Germany, started its first plasmas with the last closed flux surface (LCFS) defined by 5 uncooled graphite limiters December 2015. At end of 10 weeks long experimental campaign (OP1.1) more than 20 independent diagnostic systems were operation, allowing detailed studies many interesting plasma phenomena. For example, fast neutral gas manometers supported video cameras (including one fast-frame camera frame rates...
The magnetic diagnostic system at the Wendelstein 7-X stellarator includes three diamagnetic loops to measure flux changes in plasma. Their signals are directly related plasma energy. design with respect materials, component cooling and data acquisition is built be fully steady-state capable within harsh environment of a fusion device. During first operational phase, two have been put into operation, each them close one up-down symmetric main planes column bean-shaped triangular-shaped...
Wendelstein 7-X (W7-X) is a large optimized stellarator (B=2.5T, V=30m3) aiming at demonstrating the reactor relevance of stellarators. In 2015 W7-X will begin its first operation phase (OP1.1) with five inertially cooled inboard limiters made graphite. Assuming heat loads can be spread out evenly between limiters, 1 second discharges 2 MW ECRH heating power could run in OP1.1. The expected plasma parameters sufficient to demonstrate readiness installed diagnostics and even physics program....
For the first time absolute cross sections for electron impact ionization of hydrogen-like ions B4+, C5+, N6+ and O7+ at energies from below threshold up to about 6 keV have been measured using crossed-beams technique. All are in very good agreement with available distorted-wave exchange calculations semiempirical Lotz formula. The behaviour classically scaled along hydrogen isoelectronic sequence is discussed. A recently developed scaling technique allows us predict all non-relativistic on an scale.
The C2 fragmentation of fullerene ions C(q+)(60) (q = 1,2,3) induced by electron impact was studied for the first time. cross sections loss a fragment indicate presence two different processes. At low energies projectile leads to direct excitation giant plasmon resonance. larger than 100 eV can be described as an unsuccessful ionization. Only this second part section shows dependence on charge state q precursor ion.
The objective of Wendelstein 7-X is to demonstrate steady-state operation at β -values up 5%, ion temperatures several keV and plasma densities 2 × 1020 m−3. second operational phase foresees a fully high heat flux (HHF) divertor. Preparations are underway cope with residual bootstrap currents, either by electron cyclotron current drive or HHF protection elements. main heating system an resonance facility. Various technical improvements the gyrotrons have been implemented recently. They...
The first fast ion experiments in Wendelstein 7-X were performed 2018. They are one of the steps demonstrating optimised confinement stellarator. ions produced with a neutral beam injection (NBI) system and detected infrared cameras (IR), loss detector (FILD), charge exchange spectroscopy (FIDA), post-mortem analysis plasma facing components. distribution function at wall is being modelled ASCOT suite codes. calculate ionisation injected neutrals consecutive slowing down process ions....
Cross sections for electron-impact double ionization of Wq+ ions in charge states q=1-6 as well triple q=1-4 have been measured using the crossed-beams technique. A new semiempirical formula multiple three or more target electrons is very good agreement with measurements. Together previously obtained experimental data single tungsten ions, cross are used to study influence on state evolution if atoms exposed an electron flux at 700 eV energy. It shown that significantly influenced by...
Cross sections for the electron-impact multiple ionization and fragmentation of negatively charged fullerene ions C(-)(n) ( n = 60, 70) to C(q+)(n-m) q 1,2,3 m 0,2,4) have been measured electron energies up 1 keV. In case pure all threshold are about 10 eV higher than values expected. This shift, however, is not observed fragment ions. The experimental data indicate that there no strong electron-electron interaction between incident attached electron. A novel mechanism proposed which can be...