Generation of high-energy monoenergetic heavy ion beams by radiation pressure acceleration of ultra-intense laser pulses

A novel radiation pressure acceleration (RPA) regime of heavy ion beams from laser-irradiated ultrathin foils is proposed by self-consistently taking into account the ionization dynamics. In this regime, the laser intensity is required to match with the large ionization energy gap when the successive ionization of high-Z atoms passing the noble gas configurations [such as removing an electron from the helium-like charge state $(\text{Z}-2)^+$ to $(\text{Z}-1)^+$]. While the target ions in the laser wing region are ionized to low charge states and undergo rapid dispersions due to instabilities, a self-organized, stable RPA of highly-charged heavy ion beam near the laser axis is achieved. It is also found that a large supplement of electrons produced from ionization helps preserving stable acceleration. Two-dimensional particle-in-cell simulations show that a monoenergetic $\text{Al}^{13+}$ beam with peak energy $1\ \text{GeV}$ and energy spread of $5\%$ is obtained by lasers at intensity $7\times10^{20}\ \text{W}/\text{cm}^2$.Comment: 5 pages, 4 figure

Algebraic approach to the Hulthen potential

In this paper the energy eigenvalues and the corresponding eigenfunctions are calculated for Hulthen potential. Then we obtain the ladder operators and show that these operators satisfy SU(2) commutation relation.Comment: 8 Pages, 1 Tabl

Interaction of Close-in Planets with the Magnetosphere of their Host Stars I: Diffusion, Ohmic Dissipation of Time Dependent Field, Planetary Inflation, and Mass Loss

The unanticipated discovery of the first close-in planet around 51 Peg has rekindled the notion that shortly after their formation outside the snow line, some planets may have migrated to the proximity of their host stars because of their tidal interaction with their nascent disks. If these planets indeed migrated to their present-day location, their survival would require a halting mechanism in the proximity of their host stars. Most T Tauri stars have strong magnetic fields which can clear out a cavity in the innermost regions of their circumstellar disks and impose magnetic induction on the nearby young planets. Here we consider the possibility that a magnetic coupling between young stars and planets could quench the planet's orbital evolution. After a brief discussion of the complexity of the full problem, we focus our discussion on evaluating the permeation and ohmic dissipation of the time dependent component of the stellar magnetic field in the planet's interior. Adopting a model first introduced by C. G. Campbell for interacting binary stars, we determine the modulation of the planetary response to the tilted magnetic field of a non-synchronously spinning star. We first compute the conductivity in the young planets, which indicates that the stellar field can penetrate well into the planet's envelope in a synodic period. For various orbital configurations, we show that the energy dissipation rate inside the planet is sufficient to induce short-period planets to inflate. This process results in mass loss via Roche lobe overflow and in the halting of the planet's orbital migration.Comment: 47 pages, 12 figure

Quantum Thermalization With Couplings

We study the role of the system-bath coupling for the generalized canonical thermalization [S. Popescu, et al., Nature Physics 2,754(2006) and S. Goldstein et al., Phys. Rev. Lett. 96, 050403(2006)] that reduces almost all the pure states of the "universe" [formed by a system S plus its surrounding heat bath $B$] to a canonical equilibrium state of S. We present an exactly solvable, but universal model for this kinematic thermalization with an explicit consideration about the energy shell deformation due to the interaction between S and B. By calculating the state numbers of the "universe" and its subsystems S and B in various deformed energy shells, it is found that, for the overwhelming majority of the "universe" states (they are entangled at least), the diagonal canonical typicality remains robust with respect to finite interactions between S and B. Particularly, the kinematic decoherence is utilized here to account for the vanishing of the off-diagonal elements of the reduced density matrix of S. It is pointed out that the non-vanishing off-diagonal elements due to the finiteness of bath and the stronger system-bath interaction might offer more novelties of the quantum thermalization.Comment: 4 pages, 2 figure