arXiv subjects

Xiuzhang Tang

Publications and source records attributed to Xiuzhang Tang.

4 recordsLinked to original sources

arXiv2011

Double-relativistic-electron-shell laser proton acceleration

A new laser-proton acceleration structure combined by two relativistic electron shells, a suprathermal electron shell and a thermal electron cloud is proposed for $a\gtrapprox80σ_0$, where a is the normalized laser field and $σ_0$ is the normalized plasma surface density. In the new region, a uniform energy distribution of several GeV and a monoenergetic hundreds-of-MeV proton beam have been obtained for $a=39.5$. The first relativistic electron shell maintains opaque for incident laser pulse in the whole process. A monoenergetic electron beam has been generated with energy hundreds of MeV and charge of hundreds of pC. It is proposed a stirring solution for relativistic laser-particle acceleration.

physics.plasm-ph↗

arXiv2008

Time-dependent energetic laser-ion acceleration by strong charge separation field

The laser-ion acceleration in the ultra-short and ultra-intense laser-matter interactions attracts more and more interest nowadays. Since electrons gain relativistic energy from laser pulse in a period of several femtoseconds and driven away by the ponderomotive force of laser pulse, a huge charge-separation field pulse is generated. In general cases, the ion acceleration is determined by this charge-separation field. A novel general time-dependent solution for laser-plasma isothermal expansions into a vacuum with different types of the scale length of the density gradient which correspond to different charge separation forms is obtained. The previous solutions are some special cases of our general solution. A series of new solutions have been proposed and may be used to predict new mechanisms of ion acceleration. However, many unaccounted idiographic solutions that may be used to reveal new acceleration mode of ions such as shock wave acceleration, may be deduced from our general solutions.

physics.plasm-ph↗

arXiv2008

Time-dependent energetic proton acceleration and scaling laws in ultra-intense laser pulses interactions with thin foils

A two-phase model, where the plasma expansion is an isothermal one when laser irradiates and a following adiabatic one after laser ends, has been proposed to predict the maximum energy of the proton beams induced in the ultra-intense laser-foil interactions. The hot-electron recirculation in the ultra-intense laser-solid interactions has been accounted in and described by the time-dependent hot-electron density continuously in this model. The dilution effect of electron density as electrons recirculate and spread laterally has been considered. With our model, the scaling laws of maximum ion energy have been achieved and the dependence of the scaling coefficients on laser intensity, pulse duration and target thickness have been obtained. Some interesting results have been predicted: the adiabatic expansion is an important process of the ion acceleration and cannot be neglected; the whole acceleration time is about 10-20 times of laser pulse duration; the larger the laser intensity, the more sensitive the maximum ion energy to the change of focus radius, and so on.

physics.plasm-ph↗

arXiv2008

Two-dimension plasma expansions with anisotropic pressure

A two-dimension self-similar solution is proposed for a plasma expansion with anisotropic pressure. With the solution, it depends on the relationship between the ratio of the longitudinal and the transverse temperature of the plasma, $κ^2$ and the electron-ion mass ratio, $μ$, that the plasma front is composed by a part of hyperbolic (or a plane) and a small pointed projection at the center or a part of an ellipse. Zhang and coworkers's experiments (PRL, 99, 167602 (2007))support our results for $κ^2\in(τ,1]$. For $κ^2\leqτ$, there is an anomalous high-energy plasma emission at the angle of near $90^{\text{o}}$ due to longitudinal Coulomb explosion.

physics.plasm-ph↗