scholarly journals Plasma density measurements using chirped pulse broad-band Raman amplification

2013 ◽  
Vol 103 (12) ◽  
pp. 121106 ◽  
Author(s):  
G. Vieux ◽  
B. Ersfeld ◽  
J. P. Farmer ◽  
M. S. Hur ◽  
R. C. Issac ◽  
...  
Keyword(s):  
Plasma Density ◽  
Broad Band ◽  
Raman Amplification ◽  
Density Measurements ◽  
Chirped Pulse

Combined influence of axial electron temperature and exponential plasma density ramp on the self-focusing of a chirped laser in plasma

2020 ◽  
Vol 75 (7) ◽  
pp. 671-675
Author(s):  
Niti Kant ◽  
Vishal Thakur
Keyword(s):  
Electron Temperature ◽  
Pulse Laser ◽  
Plasma Density ◽  
Beam Width ◽  
Spot Size ◽  
Higher Order ◽  
The Self ◽  
Chirped Pulse ◽  
Self Focusing ◽  
Paraxial Ray

AbstractAn analysis of the self-focusing of highly intense chirped pulse laser under exponential plasma density ramp with higher order value of axial electron temperature has been done. Beam width parameter is derived by using paraxial ray approximation and then solved numerically. It is seen that self-focusing of chirped pulse laser is intensely affected by the higher order values of axial electron temperature. Further, influence of exponential plasma density ramp is studied and it is concluded that self-focusing of laser enhances and occurs earlier. On the other hand defocusing of beam reduces to the great extent. It is noticed that the laser spot size reduces significantly under joint influence of the density ramp and the axial electron temperature. Present analysis may be useful for the analysis of quantum dots, the laser induced fusion and etc.

scholarly journals Solar flares observed by Rosetta at comet 67P/Churyumov-Gerasimenko

2019 ◽  
Vol 630 ◽  
pp. A49 ◽  
Author(s):  
N. J. T. Edberg ◽  
F. L. Johansson ◽  
A. I. Eriksson ◽  
D. J. Andrews ◽  
R. Hajra ◽  
...  
Keyword(s):  
Plasma Density ◽  
Solar Flares ◽  
Langmuir Probe ◽  
Extreme Ultraviolet ◽  
Vantage Point ◽  
Spectral Model ◽  
Time Of Arrival ◽  
Observable Effect ◽  
Density Measurements ◽  
Comet 67P

Context. The Rosetta spacecraft made continuous measurements of the coma of comet 67P/Churyumov-Gerasimenko (67P) for more than two years. The plasma in the coma appeared very dynamic, and many factors control its variability. Aims. We wish to identify the effects of solar flares on the comet plasma and also their effect on the measurements by the Langmuir Probe Instrument (LAP). Methods. To identify the effects of flares, we proceeded from an existing flare catalog of Earth-directed solar flares, from which a new list was created that only included Rosetta-directed flares. We also used measurements of flares at Mars when at similar longitudes as Rosetta. The flare irradiance spectral model (FISM v.1) and its Mars equivalent (FISM-M) produce an extreme-ultraviolet (EUV) irradiance (10–120 nm) of the flares at 1 min resolution. LAP data and density measurements obtained with the Mutual Impedence Probe (MIP) from the time of arrival of the flares at Rosetta were examined to determine the flare effects. Results. From the vantage point of Earth, 1504 flares directed toward Rosetta occurred during the mission. In only 24 of these, that is, 1.6%, was the increase in EUV irradiance large enough to cause an observable effect in LAP data. Twenty-four Mars-directed flares were also observed in Rosetta data. The effect of the flares was to increase the photoelectron current by typically 1–5 nA. We find little evidence that the solar flares increase the plasma density, at least not above the background variability. Conclusions. Solar flares have a small effect on the photoelectron current of the LAP instrument, and they are not significant in comparison to other factors that control the plasma density in the coma. The photoelectron current can only be used for flare detection during periods of calm plasma conditions.

First results from plasma density measurements in the FTU tokamak by means of a two-frequency pulsed time-of-flight refractometer

2012 ◽  
Vol 38 (4) ◽  
pp. 343-351 ◽  
Author(s):  
V. G. Petrov ◽  
A. Yu. Malyshev ◽  
V. K. Markov ◽  
A. A. Petrov ◽  
F. Avino ◽  
...  
Keyword(s):  
Plasma Density ◽  
Time Of Flight ◽  
Density Measurements ◽  
First Results
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