Comprehensive experimental investigation of the region of low-threshold optical breakdown in a disperse gas medium

1984 ◽  
Vol 5 (2) ◽  
pp. 230-232
Author(s):  
I. Ya. Korolev ◽  
T. P. Kosoburd ◽  
�. M. Krikunova ◽  
Yu. M. Sorokin
Keyword(s):  
Experimental Investigation ◽  
Optical Breakdown ◽  
Low Threshold ◽  
Gas Medium

scholarly journals The Plant Nutrition from the Gas Medium in Greenhouses: Multilevel Simulation and Experimental Investigation

Plant Science ◽  
10.5772/53604 ◽  
2012 ◽  
Author(s):  
A.V. Vakhrushev ◽  
A.Yu. Fedotov ◽  
A.A. Vakhrushev ◽  
V.B. Golubchikov ◽  
E.V. Golubchikov
Keyword(s):  
Experimental Investigation ◽  
Plant Nutrition ◽  
Gas Medium

An Experimental Investigation of Natural Convection From an Isothermal Horizontal Plate

1989 ◽  
Vol 111 (4) ◽  
pp. 904-908 ◽  
Author(s):  
A. M. Clausing ◽  
J. J. Berton
Keyword(s):  
Experimental Investigation ◽  
Natural Convection ◽  
Rayleigh Number ◽  
Richardson Number ◽  
Horizontal Plate ◽  
Convection Regime ◽  
Variable Property ◽  
Nusselt Number Correlation ◽  
Gas Medium ◽  
Large Rayleigh Number

An investigation of natural convection from a heated, upward-facing, square, horizontal plate to a surrounding gas medium is described in this paper. The results of the experimental investigation provide an improved correlation for the natural convection regime by accounting for variable property effects and extend the applicable Rayleigh number (Ra) range of the correlation over previous research. The large Rayleigh number regime is emphasized. The value of the Richardson number (Ri) at which combined convection influences become important is also determined. The ratio of the plate wall temperature Tw to the ambient temperature T∞ is incorporated into the Nusselt number correlation in order to account for variable property influences. A cryogenic heat transfer tunnel, with test section temperatures that are varied between 80 K and 310 K, is used to help deduce the influences of the relevant parameters. The ranges of the dimensionless parameters investigated are 2 × 108 < Ra < 2 × 1011 and 1 < Tw/T∞ < 3.1.

scholarly journals Ambient fields generated by a laser spark

Nukleonika ◽  
2016 ◽  
Vol 61 (2) ◽  
pp. 119-124
Author(s):  
Karel Rohlena ◽  
Martin Mašek
Keyword(s):  
Magnetic Field ◽  
Optical Breakdown ◽  
Plasma Radiation ◽  
Nanosecond Laser ◽  
Gaseous Environment ◽  
Electric And Magnetic Fields ◽  
Laser Spark ◽  
Spark Plasma ◽  
Gas Medium ◽  
The Magnetic Field

Abstract The electric and magnetic fields surrounding a laser spark formed after an optical breakdown due to a focused nanosecond laser beam in a gaseous environment are examined in order to assess their possible influence on the processes going on in the gas medium, mainly chemical reactions triggered by the spark plasma radiation. The magnetic field is generated by the standard mechanism of crossed electron density and temperature gradients, the electric field is supposed to be produced by the plasma polarization due to its radial expansion across the self-generated magnetic field. A simple model of spark plasma formation near the tip of the focal cone is assumed, with a delayed breakdown, which allows the focused laser light to sweep the whole volume of the forming spark right down to the focal caustic and thus to form a centimeter long plasma cone. In this conical geometry, the value of plasma electric dipole moment is evaluated as a measurable quantity as well as approximate values of the electric and magnetic field near the focal caustic, where they both tend to grow in magnitude.

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