0000000000594139

AUTHOR

Thomas Sunn Pedersen

showing 3 related works from this author

Investigation of Space-Charge Phenomena in Gas-Filled Penning Traps

2009

The centering of ions in Penning traps by a quadrupolar radiofrequency excitation in the presence of a buffer gas has been studied in the regime of high charge‐densities. It is found to deviate significantly from the single‐particle situation. In particular, the efficiency of the cooling process is affected as well as the resolving power. The behavior has been studied experimentally at the preparation trap REXTRAP and the high‐precision Penning trap setup ISOLTRAP both located at the on‐line mass separator ISOLDE at CERN. In addition, the phenomenon has been investigated numerically by a custom‐designed simulation.

Condensed Matter::Quantum GasesChemistryBuffer gasSeparator (oil production)Physics::Atomic PhysicsIon trapAtomic physicsNuclear ExperimentPenning trapISOLTRAPSpace chargeExcitationIonAIP Conference Proceedings
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Overview of first Wendelstein 7-X high-performance operation

2019

Abstract The optimized superconducting stellarator device Wendelstein 7-X (with major radius , minor radius , and plasma volume) restarted operation after the assembly of a graphite heat shield and 10 inertially cooled island divertor modules. This paper reports on the results from the first high-performance plasma operation. Glow discharge conditioning and ECRH conditioning discharges in helium turned out to be important for density and edge radiation control. Plasma densities of with central electron temperatures were routinely achieved with hydrogen gas fueling, frequently terminated by a radiative collapse. In a first stage, plasma densities up to were reached with hydrogen pellet injec…

TechnologyCONFINEMENT01 natural sciencesimpurities010305 fluids & plasmaslaw.inventionECR heatingDivertorDENSITY LIMITlawData_FILESGeneralLiterature_REFERENCE(e.g.dictionariesencyclopediasglossaries)004 Datenverarbeitung; InformatikPhysicsGlow dischargeDivertorCondensed Matter PhysicsContent (measure theory)ComputingMethodologies_DOCUMENTANDTEXTPROCESSINGElectron temperatureAtomic physicsddc:620StellaratorImpuritiesNuclear and High Energy PhysicsTechnology and Engineeringplasma performancechemistry.chemical_elementAtmospheric-pressure plasmaPHYSICSstellaratorPhysics::Plasma PhysicsNBI heating0103 physical sciencesdivertor010306 general physicsHeliumStellaratorPlasma performanceturbulenceFísicaW7-XTurbulenceTheoryofComputation_MATHEMATICALLOGICANDFORMALLANGUAGESchemistryddc:004ddc:600Energy (signal processing)SYSTEMNuclear Fusion
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Confinement in Wendelstein 7-X limiter plasmas

2017

Observations on confinement in the first experimental campaign on the optimized Stellarator Wendelstein 7-X are summarized. In this phase W7-X was equipped with five inboard limiters only and thus the discharge length restricted to avoid local overheating. Stationary plasmas are limited to low densities <2–3 · 1019 m−3. With the available 4.3 MW ECR Heating core Te ~ 8 keV, Ti ~ 1–2 keV are achieved routinely resulting in energy confinement time τE between 80 ms to 150 ms. For these conditions the plasmas show characteristics of core electron root confinement with peaked Te-profiles and positive Er up to about half of the minor radius. Profiles and plasma currents respond to on- and off-axi…

PhysicsNuclear and High Energy Physicsstellaratorconfinement0103 physical sciences010306 general physicsCondensed Matter Physics01 natural sciencesenergy confinement010305 fluids & plasmasNuclear Fusion
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