Laser driven terahertz generation in hot plasma with step density profile

2015 ◽  
Vol 22 (6) ◽  
pp. 063106 ◽  
Author(s):  
Manoj Kumar ◽  
Vipin Kumar Tripathi ◽  
Young Uk Jeong
2017 ◽  
Vol 35 (3) ◽  
pp. 528-533 ◽  
Author(s):  
K.L. Mann ◽  
V. Sajal ◽  
N.K. Sharma

AbstractA scheme of resonant terahertz (THz) radiation generation by non-linear beating of two lasers in hot magnetized plasma with step density profile is investigated. Beating lasers of frequency difference ω1 − ω2 ≈ ωp(~1 THz) is incident obliquely on plasma surface and exerts non-linear ponderomotive force on plasma electrons. The plasma electrons start oscillating in the plane of incidence and give rise to space charge field to maintain plasma neutrality. In turn, both ponderomotive force and space charge field excites a non-linear surface current, responsible for THz radiation generation on the reflection side. The coupling between plasma wave and electromagnetic wave present (inside the plasma as well as on reflection side) becomes stronger in the presence of the transverse DC magnetic field. THz radiation amplitude is optimized at an angle of incidence θ ~ 50–70°.


Author(s):  
K.R. Subramanian ◽  
A.H. King ◽  
H. Herman

Plasma spraying is a technique which is used to apply coatings to metallic substrates for a variety of purposes, including hardfacing, corrosion resistance and thermal barrier applications. Almost all of the applications of this somewhat esoteric fabrication technique involve materials in hostile environments and the integrity of the coatings is of paramount importance: the effects of process variables on such properties as adhesive strength, cohesive strength and hardness of the substrate/coating system, however, are poorly understood.Briefly, the plasma spraying process involves forming a hot plasma jet with a maximum flame temperature of approximately 20,000K and a gas velocity of about 40m/s. Into this jet the coating material is injected, in powder form, so it is heated and projected at the substrate surface. Relatively thick metallic or ceramic coatings may be speedily built up using this technique.


1997 ◽  
Vol 91 (4) ◽  
pp. 761-767 ◽  
Author(s):  
D. HENDERSON ◽  
S. SOKOŁOWSKI ◽  
R. ZAGORSKI ◽  
A. TROKHYMCHUK

1981 ◽  
Vol 64 (11) ◽  
pp. 68-74
Author(s):  
Isamu Nagano ◽  
Masayoshi Mambo ◽  
Tetsuo Fukami ◽  
Koji Namba ◽  
Iwane Kimura

1987 ◽  
Vol 48 (C9) ◽  
pp. C9-383-C9-386
Author(s):  
C. MÖLLER ◽  
R. Y. YIN ◽  
M. LAMOUREUX
Keyword(s):  
X Ray ◽  

1983 ◽  
Vol 100 ◽  
pp. 145-146
Author(s):  
A. H. Nelson ◽  
T. Matsuda ◽  
T. Johns

Numerical calculations of spiral shocks in the gas discs of galaxies (1,2,3) usually assume that the disc is flat, i.e. the gas motion is purely horizontal. However there is abundant evidence that the discs of galaxies are warped and corrugated (4,5,6) and it is therefore of interest to consider the effect of the consequent vertical motion on the structure of spiral shocks. If one uses the tightly wound spiral approximation to calculate the gas flow in a vertical cut around a circular orbit (i.e the ⊝ -z plane, see Nelson & Matsuda (7) for details), then for a gas disc with Gaussian density profile in the z-direction and initially zero vertical velocity a doubly periodic spiral potential modulation produces the steady shock structure shown in Fig. 1. The shock structure is independent of z, and only a very small vertical motion appears with anti-symmetry about the mid-plane.


Sign in / Sign up

Export Citation Format

Share Document