Dynamics of a dense laboratory plasma jet investigated using soft x-ray laser interferometry

Abstract

The formation and evolution of a collisional aluminum plasma jet created by optical laser irradiation of triangular grooves with pulses of 120ps duration at an intensity of 1x10(12)W cm(-2) were studied with experiments and simulations. Series of high-contrast soft x-ray laser interferograms obtained with a 46.9nm laser mapped the plasma density evolution of an initially narrow plasma jet that expands along the symmetry plane and evolves into a broader plasma plume with significant side lobes. Two-dimensional simulations performed using the radiation hydrodynamic code HYDRA reveal that the jet formation is initiated by accelerated material ablated from the vertex and is augmented by the continual sequential arrival of wall material along the symmetry plane, where it collides and is redirected outward. Radiative cooling is identified as an important process in maintaining the collimation of the jet. These results demonstrate that well collimated collisional plasma jets with parameters in a range of interest can be generated with low-energy laser pulses (<1J) , opening the possibility of studying relevant plasma phenomena in a small laboratory setting.

Influence of Cathode Shape on Vacuum Arc Thruster Performance and Operation

“…For example, custom cathode surface profiles have already been shown to have a significant effect on the emitted macroparticle distribution of a vacuum arc [5]. In addition, convergent plasma jet flows are generating increasing interest in research areas such as astrophysical jets [6], laser ablation [7], and nuclear fusion [8]. We propose to assess their feasibility in propulsion applications.…”

Modeling of annular-laser-beam-driven plasma jets from massive planar targets

“…Unfortunately, information about the early plasma dynamics was limited due to the high opacity of dense plasma to the probe. Recently, a table top capillary X-ray laser was applied to an investigation of jet dynamics when produced from grooved targets (Grava et al, 2008).…”

Optical interferometric analysis of colliding laser produced air plasmas

“…[1][2][3][4][5] The dynamics of laser induced plasma has been studied by various techniques, such as shadowgraph, 2,3 fast photography, 5,6 laser interferometry, [7][8][9] and laser induced fluorescence. 10 However, laser interferometry is the only tool that can be used to obtain three-dimensional ͑3D͒ density distribution.…”

“…In order to create a pair of colliding plasmas, a variety of beam-target configurations were employed, including dual beam/parallel planar targets, 16 split beam/single target, 8,15,17 and single beam/orthogonal-planar target. 7,18 However, because of the strong departure from cylindrical symmetry in these experimental schemes, it is difficult to retrieve the 3D distribution of the electron density. In order to overcome this problem, Smith et al 8,15 performed a tomographic technique with multiple two-dimensional ͑2D͒ phase maps to construct the 3D distribution of the electron density.…”