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Topic: Plasma diagnostics

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In the News (Wed 26 Jun 19)

  Plasma diagnostics - Wikipedia, the free encyclopedia
Plasma diagnostics are experimental techniques used to measure properties of a plasma such as temperature and density.
This means that the electric field caused by the difference between the potential of the probe and the plasma potential at the place where the probe is located is limited to the volume inside the probe sheath boundary.
If the plasma (or one ionic component of the plasma) is flowing in the direction of the line of sight to the observer, emission lines will be seen at a different frequency due to the Doppler effect.
en.wikipedia.org /wiki/Plasma_diagnostics   (731 words)

 Plasma (physics) - Wikipedia, the free encyclopedia
Plasma frequency: The electron plasma frequency (measuring plasma oscillations of the electrons) is large compared to the electron-neutral collision frequency (measuring frequency of collisions between electrons and neutral particles).
Plasma temperature is commonly measured in Kelvin or electron volts, and is (roughly speaking) a measure of the thermal kinetic energy per particle.
The dynamics of plasmas interacting with external and self-generated magnetic fields are studied in the academic discipline of magnetohydrodynamics.
en.wikipedia.org /wiki/Plasma_(physics)   (3917 words)

 Encyclopedia :: encyclopedia : Plasma physics   (Site not responding. Last check: 2007-10-31)
In physics and chemistry, a plasma is an ionized gas, and is usually considered to be a distinct phase of matter.
Since the space between the stars is filled with a plasma, although a very sparse one (see interstellar and intergalactic medium), essentially the entire volume of the universe is plasma.
The ion temperature in a cold plasma is often near the ambient temperature.
www.hallencyclopedia.com /Plasma_physics   (2904 words)

 Plasma Diagnostics   (Site not responding. Last check: 2007-10-31)
We have developed a diagnostic technique to determine the density and velocity distribution of the alpha particles, based on the scattering of 10 micron light generated by a CO laser from alpha particles in the plasma.
In a high temperature plasma all of the atoms of the filling gas, deuterium and tritium in the case of a fusion reactor, are completely ionized and will remain so if the temperature is maintained.
To properly simulate CTS for alpha particle measurements, a proof-of-principle test was performed which relies on scattering from plasma electrons at large shifts from the pulsed laser frequency near the electron plasma resonance.
www.ornl.gov /sci/lasers_optics_diagnostics/alot/plasma.htm   (526 words)

 Learn more about Plasma physics in the online encyclopedia.   (Site not responding. Last check: 2007-10-31)
Plasma physics is the field of physics which studies the dynamic behaviour of plasmas.
A common fluid treatment of plasmas comes from a combination of the Navier Stokes Equations of fluid mechanics and Maxwell's equations of electromagnetism.
Plasma physics is important in astrophysics in that many astronomical objects including stars, accretion disks, nebula, and the interstellar medium consist of plasma.
www.onlineencyclopedia.org /p/pl/plasma_physics.html   (288 words)

 NASA - Plasma Diagnostics
A standardized plasma diagnostic reactor, known as the "GEC Cell" is equipped with a wide range of diagnostics for measuring and understanding plasma physics and chemistry for a variety of low temperature plasmas.
This system has been used to study a variety of plasma systems, and may be applied to studies of a variety of other processes, including etch processes for sensors, plasma enhanced deposition processes of novel materials, and plasma sterilization/treatment of surfaces for flight hardware and mission diagnostics.
However, diagnostics of plasma is not always a straightforward exercise in and of itself.
www.nasa.gov /lb/centers/ames/research/technology-onepagers/plasma_diagnostics.html   (615 words)

 Plasma Diagnostics
Plasma density determination by microwave cut-off and by microwave or laser interferometer.
We have a plasma and inside the plasma we put two floating probes with the same area S and which are connected to each other by small resistor R.
In the case of absence of the plasma we have to adjust by attenuator and by phase rotator or by changing the distance (phase shift equal p) two MW signals in such a manner that the resulting signal will be equal zero.
plasma-gate.weizmann.ac.il /IPSTA/Course2001/Notes/YK/YK1_2.html   (1822 words)

 VASIMR Plasma Diagnostics
Incremental improvements in the diagnostics are needed in certain areas to clarify ambiguities and to develop the capability of verifying plasma detachment.
Third, a mechanism for in situ axial transport of diagnostics as big as the multi-anode RPA head is required to follow the development of the exhaust plume from regions of high to low magnetic field and to make the measurements required to validate model predictions.
These tasks are characterizing the plasma that is produced within the engine, verifying and quantifying the details of the plasma detachment process, and measuring the momentum flux in the exhaust plume for comparison with thrust stand results.
www.uh.edu /research/spg/uhdiagnostics.html   (2144 words)

 Plasma diagnostics
The wavenumber resolution is achieved in the ES diagnostics by application of the time-of-flight technique developed recently (Gusakov and Piliya 1992; Arkhipenko et al.
In paper by Gusakov et al (2000) the CES diagnostics was further developed to study broadband (strong) turbulence and then applied for study ion acoustic turbulence in the helicon discharge Selenin et al (2002).
The possibility of CES diagnostics application for investigation of plasma poloidal rotation in tokamak was shown by Budnikov et al (2002).
www.ioffe.rssi.ru /HTPPL/PlasmaDiag/EMSproblems.html   (922 words)

 Plasma and Ion Beam Diagnostics:Principles & Applications
Plasma diagnostics are process specific, and process improvement requires understanding of the plasmas involved.
Plasma diagnostics provide the information needed to analyze and improve the desired processes.
It presents commonly used plasma diagnostics, such as the use of neutral particle detectors, electric and magnetic probes, microwave interferometry, and optical diagnostics instrumentation to measure density, temperature, and kinetic energy of the plasma particles.
www.avs.org /course.instructor.static.popup.aspx?FileName=plasmaion   (235 words)

 Theoretical Plasma Spectroscopy
A reliable plasma diagnostics requires both accurate measurements and solid theoretical support in interpretation of the experimental results.
In the low-density plasmas, for example, a non-neutral regions can exist, where the plasma particle-motion effects are negligible comparing to strong macro (external) electric fields, thus making emission spectra be affected mainly by the macro fields.
In the opposite case, the high-density regime, the plasma screening is almost entirely effective, and the main source of line broadening is the micro fields generated by the charges of the chaotically moving particles.
plasma-gate.weizmann.ac.il /theory.html   (719 words)

 Plasma Spectroscopy Group
The Plasma Spectroscopy Group is conducting research in the area of atomic processes mainly in high temperature-thermonuclear fusion plasmas and X-ray astrophysics.
We develop novel XUV diagnostics to address questions related to particle transport, confinement and MHD activity in both the hot core and the cooler edge of magnetically confined toroidal plasmas.
The plasmas studied are relevant for fusion edge plasma, astrophysics and for plasma processing applications.
physics-astronomy.jhu.edu /groups/plasma   (463 words)

 Plasma physics Article, Plasmaphysics Information   (Site not responding. Last check: 2007-10-31)
Plasma physics is the field of physics which studies the dynamicbehaviour of plasmas.
Sometimes called "thefourth state of matter" (besides solid, liquid,and gas), plasma in this context refers to a gas that has been subjected to enough energy to dissociate atoms from their electrons (ionization), producing a cloudof ions and electrons.
It is also importantin hypersonic aerodynamics, since at hypersonic speeds the interaction ofthe shock wave and the boundary layer creates enough heat to ionize the air surrounding a body.
www.anoca.org /fusion/gas/plasma_physics.html   (298 words)

 Plasma Diagnostics Group
Magnetic confinement fusion uses magnetic fields to hold a plasma in place while it is heated to ignition temperature by external sources.
The thrust of the UC Davis Plasma Diagnostic Group (PDG) is the development of advanced millimeter-wave plasma diagnostic instruments and techniques on relevant magnetic fusion devices, and obtaining important physics results with these diagnostics.
A further important mission is the training of the next generation of plasma physicists and engineers.
tempest.das.ucdavis.edu /pdg   (195 words)

 Plasma Conferences in 1999
PLASMA '99: Research and Applications of Plasmas, 7 - 9 July 1999, Space Research Center, Polish Academy of Sciences, Warsaw, Poland.
The Conference Workshop on applications of plasma physics, open to all registered participants, is scheduled for the afternoon of 11 July.
Plasma Turbulence and Energetic Particles in Astrophshysics, 6 - 10 September 1999, Kracow, Poland.
www.ewh.ieee.org /soc/nps/PlasConf/mtg99.html   (3985 words)

 UCD Plasma Diagnostics and Millimeter Wave Technology Group
At the main campus, the primary laboratory facilities include a far-infrared and millimeter wave magnetic fusion plasma diagnostics laboratory, a microwave/millimeter wave instrumentation and quasi-optics facility, high power microwave source and plasma interaction laboratory, and the synchrotron radiation light source laboratory comprising a total of 10,000 square feet.
Several large (~1-2m) plasma chambers permit the careful investigation of the physics associated with laser fusion by scaling the laser wavelength to the microwave region and consequently the micron-millimeter sized targets to meter scale lengths.
A variety of plasma simulation codes are available which range from 1-D electrostatic codes to a 2-D electromagnetic, particle code (ZOHAR) through 2-D hybrid codes, where the ions are represented as particles and the electrons as a fluid.
tempest.das.ucdavis.edu /facilities/davis.html   (1432 words)

 Plasma Processing   (Site not responding. Last check: 2007-10-31)
Fundamental understanding of plasma processes is now sufficient that plasma models are emerging as tools for the developing new plasma equipment and processes, as well as, the diagnosing process difficulties.
In addition, plasma diagnostics are now being implemented as process monitors, end point detectors, and process controllers to improve processing flexibility and reliability.
Studied the ion-enhance surface kinetics that are responsible for directional plasma etching using beams to simulate the fluxes which impinge on the surfaces during processing.
www.plasma-processing.com   (4334 words)

 Research Areas   (Site not responding. Last check: 2007-10-31)
West Virginia University's experimental plasma research program has concentrated on fundamental problems of plasma behavior that are also relevant to the understanding of processes that occur naturally in space plasmas and in man-made fusion plasmas.
The helicon source is also used to generate the plasma in a large space simulation chamber in which experiments on collisionless magnetic reconnection and the effects of the space plasma environment on scientific spacecraft are performed.
In addition, the plasma physics group has ongoing projects involving studies of sheath formation in space-relevant plasmas, the analysis of data from scientific spacecraft (Ulysses and Pioneer Venus Orbiter), the development of neutral atom imaging diagnostics for fusion and space experiments, and the investigation of nonlinear processes in low-temperature, optically pumped, plasmas.
www.as.wvu.edu /phys/plasma.htm   (397 words)

An example of a recent plasma diagnostic study is that of the gas temperature in an argon/hydrogen/methane plasma used for nanocrystalline diamond deposition.
A.K. Srivastava and J. Asmussen, "Comparison of the operational performance of a compact ECR plasma source at excitation frequencies of 2.45 GHz and MHz" J. of Vac.
A.K. Srivastava, J. Asmussen, T. Antaya and K. Harrison, "The study of a 2.45 GHz plasma source as a plasma generator for the SCECR Electron Cyclotron Ion Source," Rev. Sci.
www.egr.msu.edu /~hogant/Cleanroom/plasma_diagnostics.htm   (431 words)

In particular, we have developed plasma diagnostics for semiconductor processing discharges and have extensive experience in determining plasma kinetics.
A pyrex tube plasma system for easy generation and diagnostics of plasmas at a large variety of pressures and and in a large variety of gas mixtures.
A pinhole aperture to the plasma allows direct plasma ion detection of either positive or negative ions, and neutrals can be detected by using the filaments.
www.utdallas.edu /~overzet/PALab.html   (1249 words)

 CPST - Plasma Diagnostics
The rapid development of plasma technology and tailored sources require detailed understanding of underlying mechanisms.
Plasma diagnostics are the key to better insight, improved performance, and control.
In the CPST an exceptional wide range of diagnostics is available, and new techniques are continuously developed.
www.ruhr-uni-bochum.de /cpst/english/diagnostics.html   (86 words)

 Plasma Diagnostics
These diagnostics have been carefully selected to take account of their feasibility and endurance and compatibility with the nuclear environment of ITER, to minimise their impact on machine integrity and reliability, and to minimise cost.
For all these diagnostics more than 220 professional years of effort in design, procurement monitoring and implementation during construction is envisaged in participating laboratories, outside the integration effort within the ITER project itself.
Further details on the overview of plasma diagnostics can be found in the ITER Technical Basis.
www.iter.org /diagnostics.htm   (170 words)

 Plasma Science and Technology
Magnetic confinement fusion devices are designed to confine hot, dense plasma for a sufficient period of time (a few seconds) for nuclei to fuse by overcoming their natural repulsive forces.
Due to the coupling of ionized particles and fields, any plasma system exhibits coherence and must be treated as an interactive system and not simply as an aggregate of parts.
The Plasma Laboratory, University of Tromso Tromso, Norway
www.plasmas.com /fusion-mag.htm   (1841 words)

 Session NR1 - Plasma Diagnostics III.
The plasma was irradiated by frequency-quadrupled (266nm) and frequency-doubled (532 nm) Nd:YAG laser beams originating from the same laser oscillator; the 266 nm beam causes photodetachment, while the 532 nm beam serves as the light source for Thomson scattering.
It was so arranged that the 266 nm laser pulse irradiates the plasma 10 ns (>laser pulse width) earlier than the 532 nm laser pulse and, in the observation region, the focused thin 532 nm beam forms the coaxial core of the unfocused 266 nm beam.
Measurements for inductively coupled NF_3(5%)/Ar and SF_6(5%)/Ar plasmas at 25 mTorr with electron densities of \sim 10^11 cm^-3 indicated that the negative ion density is of comparable magnitude to the electron density.
flux.aps.org /meetings/YR01/GEC01/abs/S210.html   (1433 words)

 Amazon.com: Laser Aided Diagnostics of Gases and Plasmas (Series on Plasma Physics): Books: K Muraoka,M Maeda   (Site not responding. Last check: 2007-10-31)
Professors Muraoka and Maeda are longtime pioneers in laser-aided diagnostics of plasmas and gases.
The first part presents a general introduction to the laser-aided study of gases and plasmas, including the various principles and hardware needed for each method, while the second part describes the applications of each general system in detail.
This chapter is an overview of some of the important features of gases and plasmas, and of the role that laser-aided diagnostics play in understanding them.
www.amazon.com /Aided-Diagnostics-Plasmas-Plasma-Physics/dp/0750306432   (752 words)

 Plasma Measurements and Diagnostics   (Site not responding. Last check: 2007-10-31)
Making comprehensive measurements of plasma parameters will be crucial to attainment and control of burning plasma conditions in ITER and to the conduct of the science and technology studies - detailed elsewhere within this site - to be conducted in this regime.
ITER must attain this same degree of plasma diagnostic excellence and must also address the further requirements - barely touched upon in present tokamaks - of providing detailed data on the birth, energy loss and eventual thermalization and exhaust of fusion-generated alpha-particles.
Requirements for ITER plasma measurements have received extensive scrutiny by the world fusion science and plasma diagnostics communities and both measurement requirements and likely solutions have been documented in the ITER Physics Basis.
fusion.gat.com /iter-ga/plasma_measurements.html   (202 words)

 Principles of Plasma Diagnostics - Cambridge University Press   (Site not responding. Last check: 2007-10-31)
It develops from first principles the concepts needed to plan, execute and interpret plasma measurements, making it a suitable book for graduate students and professionals with little plasma physics background.
The book will also be a valuable reference for seasoned plasma physicists, both experimental and theoretical, as well as those with an interest in space and astrophysical applications.
"Of the many texts on plasma diagnostics, none are as comprehensive and yet managable as this excellent book by Ian Hutchinson...I highly recommend it, both as a graduate classroom text, and as a reference text for specialists in all branches of plasma physics." La Physique au Canada
www.cambridge.org /us/catalogue/catalogue.asp?isbn=052167574X   (237 words)

 Plasma Science and Technology - Resources - Topics
Plasma science and technology has tremendous, largely untapped potential for 21st century applications over the full range of energy, time, and spatial scales.
plasma chemistry (produce active species to etch, coat, clean and otherwise modify materials)
laser and plasma wave undulators for femtosecond pulses of X-rays and gamma rays
www.plasmas.org /topics.htm   (287 words)

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