In order to study effect of Compton scattering on protons accelerated along the normal direction of the target back side in the plasma, based on the model of multi-photon nonlinear Compton scattering and plasma particle-in cell simulation, the accelerated protons were analyzed and simulated, and a new mechanism of protons accelerated by the electrostatic field formed by incident laser and Compton scattering on the plasma face was put forward, then some important data were given out. The results show that the energetic electron numbers induced by Compton scattering in plasma are increased so that the electrostatic field on the target face of the energetic electrons is increased, and higher accelerated energy is absorbed by the protons. The proton gets the accelerated energy from the plasma of the gradual density scale length by Compton scattering higher than the energy getting from the plasma of the steep density scale length, and the key cause is that the effect of the electrostatic field increased by Compton scattering effectively compensates the loss energy of the electron in the transporting energy to the plasma as the increasing of the laser modulation instability taking place under Compton scattering. Therefore, it is perfect to accelerate protons with plasma of the gradual density scale length under Compton scattering.%为了研究等离子体中Compton散射对靶背法向方向加速质子的影响,采用多光子非线性Compton散射模型和等离子体模拟方法,对Compton散射下等离子体中的质子加速进行了理论分析和数值模拟,提出了将入射光和Compton散射光作为在等离子体靶表面处形成的静电场加速质子的新机制,得到了质子加速的一些重要数据.结果表明,Compton散射使等离子体内产生的高能电子数增加,高能电子靶表面上所产生的静电场增强,从而使质子获得更高的加速能量;散射使静电场增强效应,有效地补偿了因激光调制不稳定性增强而造成电子在向等离子体输运过程中的能量损失,从而使质子从平缓密度标长等离子体中获得的加速能量高于从陡峭密度标长等离子体中获得的加速能量.因此,采用Compton散射下的平缓密度标长等离子体加速质子较为理想.
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