Formation of laser plasma channels in a stationary gas

Abstract

The formation of plasma channels with nonuniformity of about ± 3.5% has been demonstrated. The channels had a density of 1.2×10 19 cm -3 with a radius of 15 µm and with length ≥ 2.5 mm. The channels were formed by 0.3 J, 100 ps laser pulses in a nonflowing gas, contained in a cylindrical chamber. The laser beam passed through the chamber along its axis via pinholes in the chamber walls. A plasma channel with an electron density on the order of 10 18 -10 19 cm -3 was formed in pure He, N 2 , Ar, and Xe. A uniform channel forms at proper time delays and in optimal pressure ranges, which depend on the sort of gas. The influence of the interaction of the laser beam with the gas leaking out of the chamber through the pinholes was found insignificant. However, the formation of an ablative plasma on the walls of the pinholes by the wings of the radial profile of the laser beam plays an important role in the plasma channel formation and its uniformity. A low current glow discharge initiated in the chamber slightly improves the uniformity of the plasma channel, while a high current arc discharge leads to the formation of overdense plasma near the front pinhole and further refraction of the laser beam. The obtained results show the feasibility of creating uniform plasma channels in non-flowing gas targets.

A pulsed-power implementation of “Laser Gate” for increasing laser energy coupling and fusion yield in magnetized liner inertial fusion (MagLIF)

“…Energy losses are believed to occur because of this LPI, energy absorption into the window material, and from window material mixing into the fuel (which leads to enhanced radiation loss). [5][6][7][8][9][10] To reduce these losses, the LEH window could be removed before the preheating laser passes through the LEH. This concept of early-time window removal is referred to as "Laser Gate".…”

Characterization of pulsed capillary channel gas puff target using EUV shadowgraphy

“…Those targets were allow possibility to develop capillary discharge EUV laser used in many experiments, such as holography [13], interferometry [14], lithography [15] and microscopy [16]. There are many other possible application of capillary targets, such as plasma channel formation [17], a medium for high energy electron acceleration [18] or amplification of X-ray pulses, [19].…”

Laser plasma channel formation in barium vapor based on superelastic heating of electrons

“…In this work, more detailed references to the literature describing the state of research on this problem can also be found. However, laboratory investigations of plasma channels formation in stationary gas [5] are of great importance nowadays.…”

“…Impulses of high power and short duration are utilized for the formation of plasma channels in gaseous media [4,5]. A method of plasma creation based on the superelastic electron heating effect under the photoexcitation by laser radiation of resonant atoms [6][7][8][9] can be considered as an alternative to this method.…”