Plasma Ionization Mass Research Articles

Ion beams from laser-generated plasmas

Space-charge-limited heavy ion beams have been produced by utilizing the plasma blowoffs generated by 20-MW bursts of 1.06-μ radiation from an active Q-switched Nd:Yag laser. Laser power densities near a moment 1011 W/cm2 on solid targets generate thermalized plasma plumes which drift to a 15-kV gridded extraction gap where the ions are extracted, accelerated, and subsequently electrostatically focused. The spatially defined ion beams are then magnetically analyzed to determine the charge-state content in the beams. Results are presented for the more significant amounts of charge states Z?5 contained in the beams formed from carbon, aluminum, copper, and lead targets. The extraction and acceleration technique preserves time-of-flight (TOF) information in the plasma drift region, which allows plasma ion temperatures and mass flow velocities to be determined from the Maxwellian ion curve TOF shapes for the individual charge species.

Impurity Transport in the FM-1 Spherator

The confinement of $Z=2$ barium test ions in a $Z=1$ plasma was found to be strongly dependent on density and background plasma ion mass. Most of the characteristics of the parametric dependence of the barium confinement could be related to the superposition of an anomalous outward and a classical inward diffusion.

Initial stages of hydrodynamic expansion of plasma heated by intense laser radiation

The hydrodynamic equations describing the average behavior of a one-dimensionally expanding plasma heated by laser radiation are solved analytically. For the small parameter approximation, the hydrodynamic expansion depends on the parameter (16P/9Ml02)1/3τL, where P is the laser power, M is the plasma mass, l0 is the initial plasma length, and τL is the laser pulse duration. With τL=τei, the electron ion relaxation time, it is possible to compute φmax (≈5.6×10−6n04l03miT−9/2, where mi is the plasma ion mass and T is the temperature), the maximum flux density below which the hydrodynamic expansion may be neglected. We find that a 5-kJ 75-ns neodymium glass laser is capable of acheiving break-even conditions for a 50% mixture of deuterium-tritium gas.