Publications by Holger Reimerdes

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First of a kind SOLPS-ITER simulations on tokamak a configuration variable (TCV) that include nitrogen have been performed to model recent nitrogen seeded detachment experiments. Based on spectroscopic measurements, a nitrogen recycling coefficient R-p(N) ...

Most of the detachment experiments done to date on the tokamak a configuration variable (TCV), both in standard and alternative divertor geometries, focused on L-mode integrated core density ramps. In view of extending these studies to high-power, high-con ...

Multi-spectral imaging of helium atomic emission (HeMSI) has been used to create 2D poloidal maps of T-e and ne in TCV's divertor. To achieve these measurements, TCV's MANTIS multispectral cameras (Perek et al 2019 Rev. Sci. Instrum. 90 123514) simultaneou ...

The snowflake (SF) magnetic configuration is investigated as a potential power exhaust solution for a fusion reactor, but also to improve our understanding of divertor physics in general. Unlike a conventional single null (SN), it features an additional ne ...

Radial electric fields up to similar to 4 kV m(-1) are observed in the boundary between the private flux region (PFR) and the scrape-off layer (SOL) driving E X B drifts between the inner and outer targets at speeds up to 2.8 km s(-1) in the Tokamak a conf ...

The impact of plasma shaping on the properties of high density H-mode scrape-off layer (SOL) profiles and transport at the outer midplane has been investigated on Tokamaka configuration variable. The experimental dataset has been acquired by evolving the u ...

This paper reports on experimental observations on TCV with a scan in upper triangularity

{\delta }_{\mathrm{up}}

, including negative triangularity, focusing on the power fall-off length

{\lambda }_{{\rm{q}}}

in L-Mode. The upper triangularity is scann ...

Plasma exhaust has been identified as a major challenge towards the realisation of magnetic confinement fusion. To mitigate the risk that the single null divertor (SND) with a high radiation fraction in the scrape-of-layer (SOL) adopted for ITER will not e ...

Fusion power is the most significant prospects in the long-term future of energy in the sense that it composes a potentially clean, cheap, and unlimited power source that would substitute the widespread traditional nonrenewable energies, reducing the geogr ...

Building on prior analysis of ASDEX Upgrade (AUG) experiments (Henderson et al 2023 Nucl. Fusion 63 086024), this study compares simple analytical formula predictions for divertor detachment onset and reattachment timescales in JET experiments. Detachment ...

Fusion power may be seen as the energy of the future in the sense that it composes a potentially clean, cheap and unlimited power source that would reduce the worldwide dependency on non-renewable energies. Nevertheless, while nowadays the fusion reaction ...

There is currently both considerable interest in the physics of ELM transport in the scrape-off layer (SOL) and concern over the impact of the ELM power and particle loads on the divertor targets of future fusion reactors. This paper describes some experimental observations of the reaction of target floating potentials and currents during ELMS in TCV, relying principally on fast measurements of these parameters using tile embedded Langmuir probe arrays. Clear evidence is presented for rapid modifications in

A baffled snowflake minus low-field side (SF-LFS) is geometrically-optimised in tokamak a` configuration variable, increasing divertor neutral pressure, to evaluate the roles of divertor closure (comparing with an unbaffled SF-LFS) and magnetic geometry (c ...

Magnetohydrodynamic (MHD) instabilities can limit the performance and degrade the confinement of tokamak plasmas. The Tokamak à Configuration Variable (TCV), unique for its capability to produce a variety of poloidal plasma shapes, has been used to analyse various instabilities and compare their behaviour with theoretical predictions. These instabilities are perturbations of the magnetic field which usually extend to the plasma edge where they can be detected with magnetic pick-up coils as magnetic fluctuat

Tokamak à configuration variable (TCV), recently celebrating 30 years of near-continual operation, continues in its missions to advance outstanding key physics and operational scenario issues for ITER and the design of future power plants such as DEMO. The ...

Novel power exhaust solutions are being developed to address the challenge of integrating a high performance fusion core plasma with a well-protected divertor, if the single null configuration does not scale to a reactor device. This work aims to elucidate ...

Exhausting power from the hot fusion core to the plasma-facing components is one fusion energy's biggest challenges. The MAST Upgrade tokamak uniquely integrates strong containment of neutrals within the exhaust area (divertor) with extreme divertor shapin ...

This work presents the KINetic Deterministic NEutral Solver (KINDNES) and its first benchmark with EIRENE (Reiter et al., 2005). Neutral particle dynamics are crucial for fluid and gyrokinetic edge plasma simulations in magnetically confined devices. While most existing neutral models fall into either deterministic fluid approximations or Monte Carlo kinetic models, KINDNES offers the advantages of a kinetic model without the drawback of the statistical error inherent to Monte Carlo codes. KINDNES, original

The research programme performed on the Mega Amp Spherical Tokamak (MAST) Upgrade experiment has made significant advances in developing the physics understanding of low aspect ratio tokamaks in support of the operation of ITER and design of fusion powerplants. High performance plasma scenarios have been developed to facilitate a broad programme of experiments, in which confinement is constrained by the presence of m/n = 2/1 modes that cause substantial losses of fast ions. The onset of these modes coincide

The Swiss Plasma Center is upgrading the TCV tokamak to test a tightly baffled, long-legged divertor (TBLLD), a novel concept that promises to enhance power exhaust capabilities with minimal modification to the magnetic configuration [1,2]. Simulations using the SOLPS-ITER code indicate that a TBLLD can improve TCV’s power exhaust capability by an order of magnitude compared to the unbaffled configuration [2]. Tight baffling sustains a high poloidal neutral density gradient, thereby, increasing the neutral

Holger Reimerdes

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Comparison of high density and nitrogen seeded detachment using SOLPS-ITER simulations of the tokamak a configuration variable

Nitrogen-seeded divertor detachment in TCV L-mode plasmas

Validation of 2D T e and n e measurements made with Helium imaging spectroscopy in the volume of the TCV divertor

The effect of the secondary x-point on the scrape-off layer transport in the TCV snowflake minus divertor

Relevance of E x B drifts for particle and heat transport in divertors

The effect of plasma shaping on high density H-mode SOL profiles and fluctuations in TCV

Dependence of the L-Mode scrape-off layer power fall-off length on the upper triangularity in TCV

Assessment of alternative divertor configurations as an exhaust solution for DEMO

A Variable Structure Control Scheme Proposal for the Tokamak a Configuration Variable

Comparison of reduced model predictions for divertor detachment onset and reattachment timescales in ASDEX Upgrade and JET experiments

Sliding Surface Based Schemes for the Tokamak a Configuration Variable

ELM driven divertor target currents on TCV

Power exhaust and core-divertor compatibility of the baffled snowflake divertor in TCV

MHD stability limits in the TCV tokamak

Experimental research on the TCV tokamak

X-point radiator and power exhaust control in configurations with multiple X-points in TCV

Divertor Shaping with Neutral Baffling as a Solution to the Tokamak Power Exhaust Challenge

First benchmark between the KINetic Deterministic NEutral Solver (KINDNES) and EIRENE

Overview of the MAST Upgrade physics programme: testing novel concepts at low aspect ratio to inform future devices

Assessing the Tightly-Baffled, Long-Legged Divertor (TBLLD) concept in TCV