Stable dense plasma jets produced at laser power densities around 1014W∕cm2

Abstract

The results of investigations are presented that are connected with defocused laser beam–planar target interaction. Following the very large focus laser-plasma interaction experiments on the Nova [H. T. Powell, J. A. Caird, J. E. Murray, and C. E. Thompson, 1991 ICF Annual Report UCRL-LR-105820-91, p. 163 (1991)] and GEKKO-XII [C. Yamanaka, Y. Kato, Y. Izawa, K. Yoshida, T. Yamanaka, T. Sasaki, T. Nakatsuka, J. Kuroda, and S. Nakai, IEEE J. Quantum Electron. QE-17, 1639 (1981)] lasers, as well as on the National Ignition Facility (NIF) laser [W. J. Hogan, E. I. Moses, B. E. Warner, M. S. Sorem, and J. M. Soures, Nucl. Fusion 41, 567 (2001)] with generation of high Mach number jets, this paper is devoted to similar jet generation with very detailed measurements of density profiles by using high-power lasers at large focus conditions. The experiment was carried out with target materials of different mass densities (Al, Cu, Ag, Ta, and Pb) using the Prague Asterix Laser System (PALS) iodine laser [K. Jungwirth, A. Cejnarova, L. Juha, B. Kralikowa, J. Krasa, E. Krousky, P. Krupickova, L. Laska, K. Masek, A. Prag, O. Renner, K. Rohlena, B. Rus, J. Skala, P. Straka, and J. Ullschmied, Phys. Plasmas 8, 2495 (2001)]. The investigations were conducted for the laser radiation energy of 100J at two wavelengths of 1.315 and 0.438μm (the first and third harmonics of laser radiation), pulse duration of 0.4ns, and a focal spot radius of 300μm. Most of the experimental data were obtained by means of a three-frame laser interferometer and an x-ray streak camera; the crater parameters were obtained by using the crater replica technique. These investigations have shown that stable dense plasma jets can be produced in a simple configuration of laser beam–planar target interaction, provided that a proper target material is used.

Al plasma jet formation via ion stream compression by surrounding low-Z plasma envelope

“…In 2006 we reported a simple method of plasma jet generation based on irradiation of flat massive targets with atomic number Z ≥ 29 (Z = 29 corresponds to Cu) by the third harmonic of a single partly defocused laser beam [1]. Our experiments at the Prague Asterix Laser System (PALS) laser facility have proved that annular target irradiation plays a decisive role in the plasma jet forming [2].…”

Self‐focusing of an electromagnetic pulse in the ionosphere

“…The small longitudinal component of E, which is always present in finite size beams can be neglected [Cicchitelli et al, 1990] in the paraxial approximation, which is adopted in the present paper. [14] The electric vector E may be expressed as…”

Astrophysical jets: Observations, numerical simulations, and laboratory experiments

“…Nicolaï ͑University of Bordeaux͒ described experiments with laser-driven plasma jets. A jet formation method developed recently 34 allows the launching of a jet having a velocity around 400 km/ s and a density of ϳ10 18 cm −3 from a solid copper target using only a relatively small laser energy. Experimental, theoretical, and numerical studies have been conducted for the interaction of this fast jet with a gas placed in front of the target.…”