In contrast to ion beams produced by conventional accelerators, ion beams accelerated by ultrashort intense laser pulses have advantages of ultrashort bunch duration and ultrahigh density, which are achieved in compact size. However, it is still challenging to simultaneously enhance their quality and yield for practical applications such as fast ion ignition of inertial confinement fusion. Compared with other mechanisms of laser-driven ion acceleration, the hole-boring radiation pressure acceleration has a special advantage in generating high-fluence ion beams suitable for the creation of high energy density state of matters. In this paper, we present a review on some theoretical and numerical studies of the hole-boring radiation pressure acceleration. First we discuss the typical field structure associated with this mechanism, its intrinsic feature of oscillations, and the underling physics. Then we will review some recently proposed schemes to enhance the beam quality and the efficiency in the hole-boring radiation pressure acceleration, such as matching laser intensity profile with target density profile, and using two-ion-species targets. Based on this, we propose an integrated scheme for efficient high-quality hole-boring radiation pressure acceleration, in which the longitudinal density profile of a composite target as well as the laser transverse intensity profile are tailored according to the matching condition.

Proton generation, transport and interaction with hollow cone targets are investigated by means of two-dimensional PIC simulations. A scaled-down hollow cone with gold walls, a carbon tip and a curved hydrogen foil inside the cone has been considered. Proton acceleration is driven by a 10²⁰ W?cm² and 1 ps laser pulse focused on the hydrogen foil. Simulations show an important surface current at the cone walls which generates a magnetic field. This magnetic field is dragged by the quasi-neutral plasma formed by fast protons and co-moving electrons when they propagate towards the cone tip. As a result, a tens of kT B_z field is set up at the cone tip, which is strong enough to deflect the protons and increase the beam divergence substantially. We propose using heavy materials at the cone tip and increasing the laser intensity in order to mitigate magnetic field generation and proton beam divergence.

介绍一种使用闪烁体耦合电子倍增电荷耦合器件（EMCCD）的方式对离子进行记录的汤姆逊能谱仪，可实现对离子能谱的实时单发测量。同时，该谱仪利用倾斜电极板对离子进行偏转，可减少由于离子打在电极板上产生的电磁噪声，能够提高实验结果的信噪比。该谱仪在北京大学4.5 MV静电加速器和2×6 MV串列加速器上进行了标定实验，测量了闪烁体将离子转化成光子后的探测效率，实验结果也验证了该谱仪的可行性和稳定性。该汤姆逊谱仪将用于北京大学激光加速器CLAPA对离子束流的测量研究。