scholarly journals Modification of the electron density profile near the upper hybrid layer during radio wave heating of the ionosphere

2002 ◽  
Vol 29 (11) ◽  
Author(s):  
N. A. Gondarenko
Keyword(s):  
Radio Wave ◽  
Electron Density ◽  
Density Profile ◽  
Electron Density Profile ◽  
Hybrid Layer ◽  
Wave Heating

scholarly journals On the determination of ionospheric electron density profiles using multi-frequency riometry

2021 ◽  
Author(s):  
Derek McKay ◽  
Juha Vierinen ◽  
Antti Kero ◽  
Noora Partamies
Keyword(s):  
Radio Wave ◽  
Electron Density ◽  
Density Profile ◽  
Electron Density Profile ◽  
Cosmic Radio ◽  
Density Profiles ◽  
Wave Absorption ◽  
Altitude Profile ◽  
Radio Wave Absorption ◽  
Electron Density Profiles

Abstract. Radio wave absorption in the ionosphere is a function of electron density, collision frequency, radio wave polarisation, magnetic field and radio wave frequency. Several studies have used multi-frequency measurements of cosmic radio noise absorption to determine electron density profiles. Using the framework of statistical inverse problems, we investigated if an electron density altitude profile can be determined by using multi-frequency, dual-polarisation measurements. It was found that the altitude profile cannot be uniquely determined from a complete measurement of radio wave absorption for all frequencies and two polarisation modes. This implies that accurate electron density profile measurements cannot be ascertained using multi-frequency riometer data alone, but that the reconstruction requires a strong additional a priori assumption of the electron density profile, such as a parameterised model for the ionisation source. Nevertheless, the spectral index of the absorption could be used to determine if there is a significant component of hard precipitation that ionises the lower part of the D region, but it is not possible to infer the altitude distribution uniquely with this technique alone.

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

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

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

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.

Impurity effects on trapped electron modes in tokamak plasmas with inverted electron density profile

2021 ◽  
Vol 28 (5) ◽  
pp. 052510
Author(s):  
X. R. Zhang ◽  
J. Q. Dong ◽  
H. R. Du ◽  
J. Y. Liu ◽  
Y. Shen ◽  
...  
Keyword(s):  
Electron Density ◽  
Density Profile ◽  
Electron Density Profile ◽  
Tokamak Plasmas ◽  
Impurity Effects ◽  
Trapped Electron

Ultrashort pulse reflectometry for electron density profile measurements

1999 ◽  
Vol 70 (1) ◽  
pp. 1038-1041 ◽  
Author(s):  
C. W. Domier ◽  
Y. Roh ◽  
N. C. Luhmann
Keyword(s):  
Electron Density ◽  
Density Profile ◽  
Ultrashort Pulse ◽  
Electron Density Profile

Improved reflectometer electron density profile measurements on DIII-D

2003 ◽  
Vol 74 (3) ◽  
pp. 1525-1529 ◽  
Author(s):  
G. Wang ◽  
L. Zeng ◽  
E. J. Doyle ◽  
T. L. Rhodes ◽  
W. A. Peebles
Keyword(s):  
Electron Density ◽  
Density Profile ◽  
Electron Density Profile
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