Geometriefaktoren von Hohlraumresonatoren zur Elektronendichte-, Dichteprofil- und Stoßfrequenzmessung von Plasmen

Geometry factors of cavity resonators for the determination of plasma electron density, density profile, and collision frequency Geometry factors of a number of cylindrical TEimn and TMimn cavity resonance modes are cal-culated as a function of the ratio of plasma and cavity radius and as a function of the radial electron density profile. In axial direction homogeneous and sinusoidal density profiles are assumed.Resonance modes with a small index l are suitable for the measurement of electron densities in narrow and dilute plasma columns; modes with an index l ≧ 2 are specially advantageous for measuring the density profile.Results of measurements of the electron density, density profile, and collision frequency in nitrogen are given.

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Der Einfluß des Entladungsgefäßes auf die Bestimmung der Plasmaelektronendichte mit Hohlraumresonatoren / The Influence of the Discharge Tube on the Determination of the Plasma Electron Density by Means of Cavity Resonators

Zeitschrift für Naturforschung A ◽

10.1515/zna-1972-0319 ◽

1972 ◽

Vol 27 (3) ◽

pp. 491-499 ◽

Cited By ~ 1

Author(s):

G Janzen

Keyword(s):

Electron Density ◽

Discharge Tube ◽

Plasma Electron ◽

Microwave Cavity ◽

Linear Perturbation ◽

Density Profiles ◽

Cavity Resonators ◽

Resonance Modes ◽

Linear Perturbation Theory ◽

Electron Density Profiles

AbstractThe eigenvalue equation of a plasma-discharge tube configuration in a cylindrical microwave cavity is derived and solved numerically by an exact theory for TMlm0 , TM0mn, and TE0mn resonance modes. The radial and axial electron density profiles are assumed to be homogeneous. The factors of proportionality between electron density and shift of the resonance frequency derived from the linear perturbation theory are compared with the exactly computed eigenvalues. Hence the range of validity of the linearly computed factors of proportionality (geometry factors) can be established. By considering the influence of the discharge tube the geometry factors are altered and consequently the sensitivity of the measurement. The influence of the discharge tube can be taken into account by means of suitable correction factors.

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Model-based real-time plasma electron density profile estimation and control on ASDEX Upgrade and TCV

Fusion Engineering and Design ◽

10.1016/j.fusengdes.2019.05.030 ◽

2019 ◽

Vol 147 ◽

pp. 111211 ◽

Cited By ~ 3

Author(s):

T.C. Blanken ◽

F. Felici ◽

C. Galperti ◽

O. Kudláček ◽

F. Janky ◽

...

Keyword(s):

Real Time ◽

Electron Density ◽

Density Profile ◽

Plasma Electron ◽

Electron Density Profile ◽

Model Based ◽

Estimation And Control ◽

And Control ◽

Profile Estimation ◽

Plasma Electron Density

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Estimation of the electron density profile in the D region from rocket measurement of VLF signals from a ground based transmitter

Electrical Engineering in Japan ◽

10.1002/ecja.4400641110 ◽

1981 ◽

Vol 64 (11) ◽

pp. 68-74

Author(s):

Isamu Nagano ◽

Masayoshi Mambo ◽

Tetsuo Fukami ◽

Koji Namba ◽

Iwane Kimura

Keyword(s):

Electron Density ◽

Density Profile ◽

Electron Density Profile ◽

Rocket Measurement ◽

D Region

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Radial density profile and stability of capillary discharge plasma waveguides of lengths up to 40 cm

High Power Laser Science and Engineering ◽

10.1017/hpl.2021.6 ◽

2021 ◽

Vol 9 ◽

Author(s):

M. Turner ◽

A. J. Gonsalves ◽

S. S. Bulanov ◽

C. Benedetti ◽

N. A. Bobrova ◽

...

Keyword(s):

Laser Pulse ◽

Electron Density ◽

Density Profile ◽

Pulse Propagation ◽

Spot Size ◽

Capillary Discharge ◽

Electron Density Profile ◽

Plasma Waveguide ◽

Wakefield Acceleration ◽

Plasma Wakefield

Abstract We measured the parameter reproducibility and radial electron density profile of capillary discharge waveguides with diameters of 650 $\mathrm{\mu} \mathrm{m}$ to 2 mm and lengths of 9 to 40 cm. To the best of the authors’ knowledge, 40 cm is the longest discharge capillary plasma waveguide to date. This length is important for $\ge$ 10 GeV electron energy gain in a single laser-driven plasma wakefield acceleration stage. Evaluation of waveguide parameter variations showed that their focusing strength was stable and reproducible to $<0.2$ % and their average on-axis plasma electron density to $<1$ %. These variations explain only a small fraction of laser-driven plasma wakefield acceleration electron bunch variations observed in experiments to date. Measurements of laser pulse centroid oscillations revealed that the radial channel profile rises faster than parabolic and is in excellent agreement with magnetohydrodynamic simulation results. We show that the effects of non-parabolic contributions on Gaussian pulse propagation were negligible when the pulse was approximately matched to the channel. However, they affected pulse propagation for a non-matched configuration in which the waveguide was used as a plasma telescope to change the focused laser pulse spot size.

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