M. Bernert
A5063429139- Magnetic confinement fusion research
- Fusion materials and technologies
- Ionosphere and magnetosphere dynamics
- Superconducting Materials and Applications
- Nuclear reactor physics and engineering
- Particle accelerators and beam dynamics
- Laser-Plasma Interactions and Diagnostics
- Plasma Diagnostics and Applications
- Solar and Space Plasma Dynamics
- Nuclear Physics and Applications
- Nuclear Materials and Properties
- Particle Accelerators and Free-Electron Lasers
- Particle Detector Development and Performance
- Atomic and Subatomic Physics Research
- Laser-induced spectroscopy and plasma
- High-Energy Particle Collisions Research
- Nuclear Engineering Thermal-Hydraulics
- Spacecraft and Cryogenic Technologies
- Geophysics and Gravity Measurements
- Ion-surface interactions and analysis
- Advanced Electron Microscopy Techniques and Applications
- Atomic and Molecular Physics
- Metal and Thin Film Mechanics
- Computer Graphics and Visualization Techniques
- Anomaly Detection Techniques and Applications
Max Planck Institute for Plasma Physics
2016-2025
Culham Science Centre
2024
Culham Centre for Fusion Energy
2024
Max Planck Society
2012-2021
National Centre for Nuclear Research
2021
Royal Military Academy
2020
Fusion (United States)
2019
Fusion Academy
2019
A future fusion reactor is expected to have all-metal plasma facing materials (PFMs) ensure low erosion rates, tritium retention and stability against high neutron fluences. As a consequence, intrinsic radiation losses in the edge divertor are comparison devices with carbon PFMs. To avoid localized overheating divertor, low-Z medium-Z impurities be inserted into convert major part of power flux facilitate partial detachment. For burning conditions ITER, which operates not far above L–H...
Detachment of high power discharges is obtained in ASDEX Upgrade by simultaneous feedback control core radiation and divertor or thermoelectric currents the injection radiating impurities. So far 2/3 ITER normalized heat flux Psep/R = 15 MW m−1 has been under partially detached conditions with a peak target well below 10 m−2. When detachment further pronounced towards lower at target, substantial changes edge localized mode (ELM) behaviour, density distribution occur. The time-averaged both...
Abstract The JET 2019–2020 scientific and technological programme exploited the results of years concerted engineering work, including ITER-like wall (ILW: Be W divertor) installed in 2010, improved diagnostic capabilities now fully available, a major neutral beam injection upgrade providing record power 2019–2020, tested technical procedural preparation for safe operation with tritium. Research along three complementary axes yielded wealth new results. Firstly, plasma delivered scenarios...
Abstract In 2021 JET exploited its unique capabilities to operate with T and D–T fuel an ITER-like Be/W wall (JET-ILW). This second major campaign (DTE2), after DTE1 in 1997, represented the culmination of a series enhancements—new fusion diagnostics, new injection capabilities, refurbishment plant, increased auxiliary heating, in-vessel calibration 14 MeV neutron yield monitors—as well as significant advances plasma theory modelling community. DTE2 was complemented by sequence isotope...
The 2014–2016 JET results are reviewed in the light of their significance for optimising ITER research plan active and non-active operation. More than 60 h plasma operation with first wall materials successfully took place since its installation 2011. New multi-machine scaling type I-ELM divertor energy flux density to is supported by principle modelling. relevant disruption experiments modelling reported a set three mitigation valves mimicking setup. Insights L–H power threshold Deuterium...
The first stable completely detached H-mode plasma in the full tungsten ASDEX Upgrade has been achieved. Complete detachment of both targets is induced by nitrogen seeding into divertor. Two new phases are added to classification described Potzel et al (2014 Nucl. Fusion 54 013001): first, line integrated density increases about 15% with partial outer Second, complete correlated appearance intense, strongly localized, radiation at X-point. Radiated power fractions, frad, increase from 50%...
In the European fusion roadmap, ITER is followed by a demonstration power reactor (DEMO), for which conceptual design under development. This paper reports first results of coherent effort to develop relevant physics knowledge that (DEMO Physics Basis), carried out experts. The program currently includes investigations in areas scenario modeling, transport, MHD, heating & current drive, fast particles, plasma wall interaction and disruptions.
In this paper, a new experimental classification of divertor detachment in ASDEX Upgrade is presented. For purpose, series ohmic and L-mode density ramp discharges at different heating powers, magnetic field directions plasma species were carried out. the first time electron volume occurrence recombination measured by means spectroscopy. It shown that not continuously evolving process but rather undergoes three distinct states while characteristics inner outer are strongly coupled. Before...
Experimental investigations carried out in the ASDEX Upgrade tokamak under various conditions demonstrate that ion heat flux at plasma edge plays a key role L-H transition physics, while electron does not seem to play any role.This is due fact governs radial electric field well induced by main ions which responsible for turbulence stabilization causing transition.The experiments have been low density branch of power threshold where and channels can be separated.In plasmas heated heating, has...
Operation of DEMO in comparison to ITER will be significantly more demanding, as various additional limitations physical and technical nature have respected. In particular a set extremely restrictive boundary conditions on divertor operation during between ELMs It is high importance describe these order consider them early possible the ongoing development concept design. This paper extrapolates existing physics basis power particle exhaust DEMO.
An overview of the H-mode threshold power in ASDEX Upgrade which addresses impact tungsten versus graphite wall, dependences upon plasma current and density, as well influence ion mass is given.Results on H-L back transition are also presented.Dedicated L-H studies with electron heating at low enable a complete separation channels, reveal that heat flux key parameter physics mechanism through main pressure gradient itself contribution to radial electric field induced flow shearing edge.The...
Future fusion reactors require a safe, steady state divertor operation. A possible solution for the power exhaust challenge is detached operation in scenarios with high radiated fractions. The radiation can be increased by seeding impurities, such as N dominant scrape-off-layer radiation, Ne or Ar SOL and pedestal Kr core radiation. Recent experiments on two of all-metal tokamaks, ASDEX Upgrade (AUG) JET, demonstrate fractions fully-detached N, conventional vertical target geometry. For both...
Abstract A double radiative feedback technique has been developed on the ASDEX Upgrade tokamak for optimization of power exhaust with a standard vertical target divertor. The main chamber radiation is measured in real time by subset three foil bolometer channels and controlled argon injection outer midplane. heat flux addition nitrogen divertor private region using either thermoelectric sensor or scaled obtained channel No negative interference two controllers observed so far. combination...
Abstract For the past several years, JET scientific programme (Pamela et al 2007 Fusion Eng. Des . 82 590) has been engaged in a multi-campaign effort, including experiments D, H and T, leading up to 2020 first with 50%/50% D–T mixtures since 1997 ever plasmas ITER mix of plasma-facing component materials. this purpose, concerted physics technology was launched view prepare campaign (DTE2). This paper addresses key elements developed by directly contributing preparation. intense preparation...
Abstract Future fusion reactors require a safe, steady state divertor operation. The required detached operation is, in tokamaks with metal walls, usually achieved by seeding of impurities, such as nitrogen. With strong levels, the dominant radiation is emitted from small, poloidally localized volume inside confined region, vicinity X-point. location radiating observed to vary relative X-point depending on and power i.e. degree detachment. At ASDEX Upgrade tokamak, position radiator can be...
The understanding of divertor physics and the evolution detachment is crucial for developing capability to model power exhaust in current experiments reliably predict it future fusion devices. In simulations ASDEX Upgrade, an experimentally observed region high density field side scrape-off layer has been recovered. Validated modeling with SOLPS5.0 shows that a detailed match plasma not only important local parameters, but can lead strong changes global parameters. Drifts play role...
Abstract The tokamak à configuration variable (TCV) continues to leverage its unique shaping capabilities, flexible heating systems and modern control system address critical issues in preparation for ITER a fusion power plant. For the 2019–20 campaign configurational flexibility has been enhanced with installation of removable divertor gas baffles, diagnostic capabilities an extensive set upgrades new dual frequency gyrotrons. baffles reduce coupling between main chamber allow detailed...
Abstract Based on particle and energy balances, a reduced model is derived for the physical mechanisms leading to occurrence of stable unstable X-point radiators (XPRs), latter also known as marfes. The roles neutral deuterium density in divertor region initiating XPRs highlighted. An access condition formulated whose parameter dependencies are consistent with experimental observations which could apply process detachment. With an exponential increase recombination rate at low temperature,...
Future fusion reactors require a safe, steady-state divertor operation. With deep detachment, which is typically induced by impurity seeding, the radiation concentrates in small region at X-point or on closed flux surfaces above X-point. This so-called radiator (XPR) moves further inside confined with increasing seeding and location can be actively controlled. At AUG, parameter space for operation an XPR was significantly extended, using active feedback location. The observed nearly whole...
Abstract Since the publication of review Progress in ITER Physics Basis (PIPB) 2007, significant progress has been made understanding processes at plasma-material interface. This review, part ITPA Nuclear Fusion Special Issue On Path to Burning Plasma Operation , presents these developments, focusing on key areas such as physics plasma exhaust, interactions, and properties plasma-facing materials their evolution under exposure. The coordinated efforts Topical Group Scrape-Off Layer Divertor...
The W-transport in the core plasma of JET is investigated experimentally by deriving W-concentration profiles from modelling signals soft x-ray cameras. For case pure neutral beam heating W accumulates (r/a < 0.3) approaching W-concentrations 10−3 between sawtooth crashes, which flatten W-profile to a concentration about 3 × 10−5. When central Ion cyclotron resonant additionally applied decays phases that exhibit changed mode activity, while also electron temperature increases and density...
In the ASDEX Upgrade tokamak, a radiation measurement for wide spectral range, based on semiconductor detectors, with 256 lines of sight and time resolution 5μs was recently installed. combination foil bolometry, it is now possible to estimate absolutely calibrated radiated power plasma fast timescales. This work introduces this diagnostic AXUV (Absolute eXtended UltraViolet) n-on-p diodes made by International Radiation Detectors, Inc. The degradation in tokamak environment shown. Even...
The high confinement mode (H-mode) is the operational scenario foreseen for ITER, DEMO and future fusion power plants. At densities, which are favorable in order to maximize power, a back transition from H-mode low (L-mode) observed. In present tokamaks, this density limit (HDL) occurs at densities on of, but below, Greenwald density.