Laser Acceleration of Ultrashort Ion Bunches and Femtosecond Neutron Sources
Laser Acceleration of Ultrashort Ion Bunches and Femtosecond Neutron Sources
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DOI：
10.1063/1.2195213
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发表时间：
2006-04
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影响因子：
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通讯作者：
A. Macchi;F. Cattani;T. Liseykina;F. Cornolti
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文献类型：
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作者：
A. Macchi;F. Cattani;T. Liseykina;F. Cornolti
我们从理论上研究了高强度圆偏振激光脉冲与过密等离子体相互作用中离子的加速。通过一维和二维粒子池（PIC）模拟，我们发现在激光-等离子体相互作用表面迅速产生高密度、短持续时间的离子束进入等离子体。这种机制与由快速电子驱动的离子加速机制在质量上有所不同，例如在目标后部的鞘层加速或在前面的激波加速，这些都发生在线极化中。一个简单的解析模型解释了数值观测，并提供了离子束速度和产生时间作为脉冲强度和等离子体密度函数的标度规律。目前基于激光脉冲圆偏振的机制导致离子能量适中（在100k - 1 MeV范围内），但离子密度很高，光束散度很低。这些离子束可能对压缩和…
We have theoretically investigated the acceleration of ions in the interaction of high intensity, circularly polarized laser pulses with overdense plasmas. By using 1D and 2D particle‐in‐cell (PIC) simulations we find that high‐density, short duration ion bunches moving into the plasma are promptly generated at the laser‐plasma interaction surface. This regime is qualitatively different from ion acceleration regimes driven by fast electrons, such as sheath acceleration at the back of the target or shock acceleration at the front, which occur for linear polarization. A simple analytical model accounts for the numerical observations and provides scaling laws for the ion bunch velocity and generation time as a function of pulse intensity and plasma density. The present mechanism based on circular polarization of the laser pulse leads to moderate ion energies (in the 100 keV–1 MeV range) but very high ion densities and low beam divergence. These ion bunches might be of interest for problems of compression and...