Observation of three-half harmonic radiation from plasmas irradiated by a 0·26 μm wavelength laser

1987 ◽  
Vol 38 (3) ◽  
pp. 445-451 ◽  
Author(s):  
C. Labaune ◽  
E. Fabre ◽  
G. Bonnaud
Keyword(s):  
Electron Density ◽  
Conversion Efficiency ◽  
Density Profile ◽  
Electron Density Profile ◽  
Light Energy ◽  
Two Dimensional ◽  
Density Profiles ◽  
Hydrodynamic Simulations ◽  
Profile Shape ◽  
Harmonic Radiation

Time-integrated measurements have been made of three-half harmonic light energy emitted from 0·26 μm laser-produced plasmas. The main results are the experimental dependence of 3/2ω0 conversion efficiency and threshold on electron density-profile shape. Various density profiles are achieved by irradiating different kinds of target; their shapes are estimated with the help of two-dimensional hydrodynamic simulations.

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.

scholarly journals Electron density profiles probed by radio occultation of FORMOSAT-7/COSMIC-2 at 520 and 800 km altitude

2015 ◽  
Vol 8 (2) ◽  
pp. 1615-1627
Author(s):  
J. Y. Liu ◽  
C. Y. Lin ◽  
H. F. Tsai
Keyword(s):  
Electron Density ◽  
Density Profile ◽  
Radio Occultation ◽  
System Simulation ◽  
Electron Density Profile ◽  
Abel Inversion ◽  
Simulation Experiments ◽  
Density Profiles ◽  
Satellite Altitude ◽  
Electron Density Profiles

Abstract. The FORMOSAT-7/COSMIC-2 (F7/C2) will ultimately place 12 satellites in orbit with two launches with 24° inclination and 520 km altitude in 2016 and with 72° inclination and 800 km altitude in 2019. In this study, we examine the electron density probed at the two satellite altitudes 500 and 800 km by means of FORMOSAT-3/COSMIC (F3/C) observations at the packing orbit 500 km altitude and mission orbit 800 km altitude, as well as observing system simulation experiments (OSSE). The electron density derived from 500 and 800 km satellite altitude of the F3/C observation and the OSSE confirm that the standard Abel inversion can correctly derive the electron density profile.

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.

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