A5056360703- Plasma Diagnostics and Applications
- Laser-induced spectroscopy and plasma
- Plasma Applications and Diagnostics
- Magnetic confinement fusion research
- Electrohydrodynamics and Fluid Dynamics
- Metal and Thin Film Mechanics
- Atomic and Molecular Physics
- Particle Detector Development and Performance
- Mass Spectrometry Techniques and Applications
- Laser Design and Applications
- Particle accelerators and beam dynamics
- Advanced Data Storage Technologies
- Particle physics theoretical and experimental studies
- Distributed and Parallel Computing Systems
- Spectroscopy and Laser Applications
- Fusion materials and technologies
- Diamond and Carbon-based Materials Research
- Semiconductor materials and devices
- Particle Accelerators and Free-Electron Lasers
- Parallel Computing and Optimization Techniques
- Superconducting Materials and Applications
- Atomic and Subatomic Physics Research
- Ionosphere and magnetosphere dynamics
- Photonic and Optical Devices
- Solar and Space Plasma Dynamics
Culham Science Centre
2017-2024
Culham Centre for Fusion Energy
2024
United Kingdom Atomic Energy Authority
2022-2024
University of Liverpool
2015-2023
Royal Military Academy
2020
Fermi National Accelerator Laboratory
1990-2016
The Open University
2004-2015
Hong Kong Metropolitan University
2014
Plasma (Russia)
2005-2006
Eindhoven University of Technology
2003-2005
We report results from the first search for νμ→νe transitions by NOvA experiment. In an exposure equivalent to 2.74×1020 protons on target in upgraded NuMI beam at Fermilab, we observe 6 events Far Detector, compared a background expectation of 0.99±0.11(syst) based Near Detector measurement. A secondary analysis observes 11 with 1.07±0.14(syst). The 3.3σ excess observed primary disfavors 0.1π<δCP<0.5π inverted mass hierarchy 90% C.L.Received 19 January...
This paper reports the first measurement using NOvA detectors of ${\ensuremath{\nu}}_{\ensuremath{\mu}}$ disappearance in a beam. The analysis uses 14 kton-equivalent exposure $2.74\ifmmode\times\else\texttimes\fi{}{10}^{20}$ protons-on-target from Fermilab NuMI Assuming normal neutrino mass hierarchy, we measure $\mathrm{\ensuremath{\Delta}}{m}_{32}^{2}=({2.52}_{\ensuremath{-}0.18}^{+0.20})\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}3}\text{ }\text{ }{\mathrm{eV}}^{2}$ and...
In recent years, the method of incoherent Thomson scattering has been applied to make measurements electron properties glow discharges used for industrial applications. These plasmas have density order and temperature a few eV. This paper reviews progress in this research area. Details experimental systems are given examples made several different types presented. A which is combined with Rayleigh provide direct neutral also described an example given. The velocity energy distribution...
The DNA molecule is observed to be very susceptible short-term exposures an atmospheric pressure plasma jet. damage induced by plasma-generated species, i.e. excited atoms, charged particles, electrons and UV light determined.
The mechanisms responsible for the propagation of first anode directed ionization wave that occurs in a straight discharge tube during breakdown are studied by means fluid model. contains argon at pressure few Torr and is operated dc voltage with cathode heated to thermal electron emission temperatures. two-dimensional model incorporates continuity momentum equations electrons, several effective excited states ions, balance equation energy Poisson equation. capable describing front way...
Electron temperature, electron density, and neutral atom density were measured in a radio-frequency (rf) inductively coupled plasma using Thomson Rayleigh scattering of laser radiation. Measurements made an argon discharge for pressures from 1 to 20 mTorr input rf powers 100 500 W. Spatial distribution profiles discharges with different aspect ratios. temperature was found depend on pressure but only weakly power. depended strongly both The be significantly depleted the center this depletion...
Electron temperature Te and density ne in the source region of an electron cyclotron resonance discharge have been measured by incoherent Thomson scattering beam from a 0.5 J yttrium aluminum garnet laser. This is first experiment which this technique, routinely used on fusion plasmas, has applied to processing plasma. Measurements were made argon at pressures 0.3 2 mTorr microwave powers 250 1000 W. Velocity distributions both parallel perpendicular magnetic field slight anisotropy was...
The plasma needle is a small atmospheric, nonthermal, radio-frequency discharge, generated at the tip of needle, which can be used for localized disinfection biological tissues. Although several experiments have characterized various qualities discharge characteristics and electrical properties are still not well known. In order to provide initial estimates on quantities such as particle densities, we employed two-dimensional, time-dependent fluid model describe needle. this balance equation...
Using laser-induced fluorescence-dip Stark spectroscopy, we performed time-resolved, direct measurements of electric-field strengths during the breakdown phase a low-pressure, pulsed discharge in xenon. With this experimental technique could for first time quantitatively measure evolution driving force plasma process: electric field. Moving ionization fronts were measured with submicrosecond resolution. These sustained by spatially narrow, rapidly moving region strong
The temporal evolution of plasma density and electron temperature in high power impulse magnetron sputtering discharges has been measured using the Langmuir probe laser Thomson scattering techniques. Measurements were performed (nonsimultaneously) at two positions within plasma, low magnetic field strength region on discharge axis trap, for peak densities 450 W cm–2 900 cm−2, respectively. maximum temperatures 6.9 × 1019 m−3 3.7 eV pulse-on time, values decayed to 4.5 1017 0.1 times up 250...
The electron energy distribution function (eedf) in an inductively coupled plasma was studied using the method of laser Thomson scattering. eedfs were measured for various conditions, at different gas pressures, and input rf powers. In high density plasmas, eedf observed to be Maxwellian, while low a non-Maxwellian observed. transition between Maxwellian attributed thermalization population higher plasmas. order completely characterize eedf, spatial temporal dependencies measurements also...
A laser spectroscopic method for sensitive electric field measurements using krypton has been developed. The Stark effect of high Rydberg states the autoionizing series can be measured by a technique called fluorescence dip spectroscopy (FDS) with spatial and temporal resolution. Calibration have performed in reference cell known they agree very well numerical solutions Schrödinger's equation jl-coupled states. application this demonstrated sheath region capacitively coupled radiofrequency...
The electron energy distribution function (EEDF) in an argon planar inductively coupled plasma was measured by the method of laser Thomson scattering. In a low-pressure discharge, clear departure from Maxwellian observed; unambiguous measurement non-Maxwellian low-density glow discharge. EEDF became higher pressure These observations were attributed to lack randomizing collisions discharge and increase number these at pressure.
We report the development of a method for measurement electric fields in glow discharge plasmas, based on Stark spectroscopy argon atoms. The is laser excitation transitions atomic argon. key feature that field determined by matching experimentally obtained absorption spectra to theoretically calculated spectra. dependence positions energy levels atoms strength was solving Schrodinger equation atom. Measurements were made sheath region using optogalvanic spectroscopy. wavelength radiation...
The discharge behaviour of a dielectric barrier (DBD) in low-pressure argon gas was investigated by experiments and modelling. electrical characteristics light emission dynamics the were measured compared with results two-dimensional fluid model. Our investigations showed that consisted single, diffuse per voltage half-cycle. breakdown phase DBD (LPDBD) to be similar ignition glow without dielectrics, described Townsend theory. stable LPDBD also plasma structure features those classical...
Abstract JET, the world’s largest operating tokamak with unique Be/W wall and tritium handling capability, completed a Deuterium-Tritium (D-T) campaign in 2021 (Maggi et al 29th Fusion Energy Conf. ) following decade of preparatory experiments, dedicated enhancements, technical rehearsals training (Horton 2016 Eng. Des. 109–111 925). Operation raises significant technical, safety scientific challenges not encountered standard protium or deuterium operation. This contribution describes...
Laser Thomson scattering was successfully applied to measure electron temperature ( T e ) and density n in a micro-discharge plasma. This is the first time that this method has been used obtain otherwise inaccessible plasma information from near vicinity (0.3 mm) of material surface. The key success suppression strong stray laser light by using triple-grating spectrometer. Values were =(0.4–1.6) eV =(6–10)×10 18 m -3 , depending on beginning pulsed discharge. technique developed here readily...
We describe measurements of plasma properties pulsed, low pressure, capacitively coupled discharges operated in argon.The research aims to determine the effect modulating radiofrequency power during discharge part pulse cycle.Measurements local electron density and optical emission were made capacitively-coupled rf generated a Gaseous Electronics Conference (GEC) reference reactor.Gas pressure was range 7 -70 Pa, 1-100 W durations 10 µs -100 ms.The results indicate that ignition afterglow...
Electron property measurements made by Langmuir probes and laser Thomson scattering have been compared in weakly magnetized plasma conditions using a planar unbalanced magnetron with the aim of assessing accuracy probe diagnostic. The were performed at several locations within magnetic field configuration, null region (≲1 mT) on discharge axis inside last closed flux surface boundary fields up to 33 mT. There was good diagnostic agreement during High Power Impulse Magnetron Sputtering, but...
Abstract Using laser Thomson scattering (LTS) and 2D optical imaging, a fireball-like discharge is detected during the positive pulse period of bipolar voltage waveforms, for circular planar unbalanced magnetron with W target operating in argon. These reverse discharges, excited voltages V pp from 200 to 300 V, sit primarily on centreline. Their establishment delayed relative initiation pulse, delay time shortening increased : they are clearly attached (anode this phase) have lifetimes...
In recent years, the method of incoherent Thomson scattering has been used in study glow discharge plasmas to measure electron properties such as density and temperature. this paper, we report development a diagnostic system that is appropriate for measurements discharges containing reactive chemical species. The new based on low-pulse-energy, high-repetition-rate YAG laser, multipass cell laser beam, an ICCD camera simultaneous detection entire scattered spectrum. Measurements made...