Investigation on Plasma Based High Energy Proton Acceleration

该项目的目标是利用等离子体与高强度、超短激光脉冲的相互作用来开发一种质子加速器，预计这种加速器将比传统加速器更紧凑。我们提出了两种质子加速方法。通过数值模拟，证实了V_P×B和尾波场共同作用于质子加速的可能性。虽然每级能量增量不大，但加速度梯度比传统的射频加速方案大几百倍。似乎有一些改进的空间，包括新的加速方案。为了进一步提高加速效率，还需要进行更详细的讨论。我们将研制一台输出能量高达1 MeV的质子源，用于质子加速方法的原理验证实验。到目前为止，已经完成了能量为30keV的质子源的研制。为了将从质子源引出的能量为30keV的质子加速到1 MeV，我们正在设计IH(交指H模)直线加速器，作为使用激光和等离子体的加速器末级的注入器。目前，我们正在考虑包括腔体结构在内的设计参数，使用计算机模拟，如MAFIA。我们计划在完成IH加速器腔的设计后制作原型加速器。

The goal of this project is to develop a proton accelerator utilizing an interaction of a plasma with a high intensity, ultrashort laser pulse, which is expected to be more compact than the conventional accelerators. We have proposed two proton acceleration methods. The possibility of proton acceleration due to both the V_P x B and the wakefield has been confirmed by performing numerical simulations. Although the energy increment per stage is not large, the acceleration gradient is several hundred times larger than that in the conventional rf acceleration scheme. There seems to be some room for making improvements including new acceleration schemes. More detailed discussions are required for further improvement of the acceleration efficiency. We are going to develop a proton source with an output energy as high as 1 MeV for the proof-of-principle experiments of the proton acceleration methods. Development of the proton source with the energy 30 keV was finished so far. In order to accelerate protons with energy 30 keV extracted from the proton source up to 1 MeV, we are under designing IH (Interdigital H-mode) linear accelerator as the injector to the final stage of the accelerator which uses laser and plasma. At present, we are considering the design parameters including the cavity structure by using computer simulations, such as MAFIA. We plan to make prototype accelerator after finishing the design of the IH accelerator cavity.