A5090386969- Magnetic confinement fusion research
- Particle accelerators and beam dynamics
- Fusion materials and technologies
- Ionosphere and magnetosphere dynamics
- Laser-Plasma Interactions and Diagnostics
- Atomic and Molecular Physics
- Plasma Diagnostics and Applications
- Nuclear Physics and Applications
- Ion-surface interactions and analysis
- Particle Accelerators and Free-Electron Lasers
- Metamaterials and Metasurfaces Applications
- Superconducting Materials and Applications
- Radiation Effects in Electronics
- Acoustic Wave Resonator Technologies
- Advanced Antenna and Metasurface Technologies
- Atomic and Subatomic Physics Research
- Radiation Therapy and Dosimetry
- Gyrotron and Vacuum Electronics Research
- Solar and Space Plasma Dynamics
- Quantum, superfluid, helium dynamics
- Advanced Frequency and Time Standards
- Electrohydrodynamics and Fluid Dynamics
- Optical Coatings and Gratings
- Nuclear physics research studies
- Fluid Dynamics and Turbulent Flows
University of Wisconsin–Madison
2012-2024
We report the first observation of global recycling coefficient R near 0.5 in Lithium Tokamak eXperiment-β (LTX-β), significantly below minimum previously reported other devices. In a series experiments with varied Li wall conditioning, estimates have been made using Lyman-α array and DEGAS2 modeling. A progressive reduction emission increased lithium an increase edge electron temperature are observed. It is also observed that increasing coating thickness, effective particle confinement time...
A comparison of three sets Lithium Tokamak Experiment-β (LTX-β) discharges is presented, each with progressively more lithium evaporatively deposited on the stainless steel plasma facing components (PFCs). Multiple observations independently indicate a reduction in recycling increasing deposition - current, discharge duration, density pumpout, and edge electron temperatures increase while neutral influx decrease. These measurements make use several new operational diagnostics upgrades that...
Abstract Recent experiments in the lithium tokamak experiment- β (LTX- ) have extended duration, performance, operating conditions, and diagnosis of flat-temperature profile, low-recycling regime first observed LTX. As expected, Li retains hydrogen suppresses edge neutral cooling, allowing increased electron temperature, roughly equal to core T e . Flat temperature profiles had been obtained transiently LTX, as plasma density decayed following cessation gas puffing. Careful control over...
Abstract We present observations, numerical simulations, and analysis from experiments in the Lithium Tokamak Experiment-Beta (LTX- β ) which electron temperature profile ( T e r )) shifts flat to peaked a tearing mode is also destabilized when average density n ave exceeds ∼10 19 m −3 . Flat obtained routinely LTX- , with lithium coated, low-recycling first wall, once external fueling stopped decays [Boyle et al 2023 Nucl. Fusion 63 056020]. In experiment, profiles can be sustained while...
Fast ions are well confined in the stochastic magnetic field of multiple-helicity (MH) reversed-field pinch (RFP), with fast ion confinement times routinely a factor 5 to 10 higher than thermal time. Recent experiments have examined behavior and beam-born three-dimensional (3D) helical RFP state. In lower current discharges, where onset state is uncertain, high power neutral beam injection (NBI) tends suppress transition single helicity mode. discharges (Ip ∼ 0.5 MA), n = quite robust, short...
Multiple bursty energetic-particle (EP) driven modes with fishbone-like structure are observed during 1 MW tangential neutral-beam injection in a reversed field pinch (RFP) device. The distinguishing features of the RFP, including large magnetic shear (tending to add stability) and weak toroidal (leading stronger drive), provide complementary environment tokamak stellarator configurations for exploring basic understanding EP instabilities. Detailed measurements mode characteristics...
In planar metamaterial lenses, the focal point moves with frequency.Here it is shown numerically that this movement can be controlled by properly engineering dimensions of metamaterialbased phase shifters constitute lens.In particular, such lenses designed to exhibit unusual chromatic aberration length increasing, rather than decreasing, frequency.It proposed an artificial "reverse" may optimize transverse resolution millimeter wave diagnostics plasmas and useful in compensating for natural...
Energetic ions are well confined in the core of reversed field pinch and a substantial population develops rapidly during tangential neutral beam injection. A saturated fast ion density is observed within several milliseconds coincides with onset energetic particle mode activity. First measurements fusion product profile determine pressure profiles, latter which when combined analysis energy distribution. These key explaining limiting behavior response to combination effects. Tearing...
While reconnection-driven ion heating is common in laboratory and astrophysical plasmas, the underlying mechanisms for converting magnetic to kinetic energy remain not fully understood. Reversed field pinch discharges are often characterized by rapid during impulsive reconnection, generating an distribution with enhanced bulk temperature, mainly perpendicular field. In Madison Symmetric Torus, a subset of strongest reconnection events develop very anisotropic, high tail parallel addition...
The neutron emissivity profile in the Madison Symmetric Torus is being reconstructed through use of a collimated detector. A scintillator-photomultiplier tube (PMT) system employed to detect fusion neutrons with plasma viewing volume defined by 55 cm deep, 5 diameter aperture. Effective detection from achieved moderation using 1300 lbs high density polyethylene shielding, which modeling predicts attenuates penetrating flux factor 104 or more. broad spectrum gamma radiation also present due...
An advanced neutral particle analyzer (ANPA) on the Madison Symmetric Torus measures deuterium ions of energy ranges 8-45 keV with an resolution 2-4 and time 10 μs. Three different experimental configurations measure distinct portions naturally occurring fast ion distributions: moving parallel, anti-parallel, or perpendicular to plasma current. On a radial-facing port, current have necessary pitch be measured by ANPA. With diagnostic positioned tangent line through core, chord integration...
A fast ion loss detector has been constructed and implemented on the Madison Symmetric Torus (MST) to investigate energetic losses transport due particle MHD instabilities. The discriminates orbits solely pitch consists of two thin-foil, collecting plates that are symmetric with respect device aperture. One plate collects signal, while second aids in minimization background noise effects. Initial measurements reported along suggestions for next design phase detector.