The transverse instability induced transparency can be detrimental in the laser-driven radiation pressure acceleration (RPA) of ions. It is the primary source of increase in the energy spread of the accelerated ion beam. In this paper, through two-dimensional particle-in-cell simulations, we demonstrate the suppression of transparency and significant improvement in the energy spread of the accelerated proton beam. This is achieved by a modified target design where a relativistically under-dense thick (micrometer size) target is placed behind a thin (nano-meter size) accelerating foil undergoing radiation pressure acceleration (RPA). The return current provided by electrons inside the thick target plays a crucial role in transparency suppression by enhancing the density and reducing the transverse modulations in the target. Physical mechanism of instability suppression is discussed in detail.

中文翻译：

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抑制横向不稳定性引起的离子在激光驱动的辐射压力加速中的透明性

横向不稳定性引起的透明性可能对离子的激光驱动辐射压力加速（RPA）有害。它是加速离子束能量扩散增加的主要来源。在本文中，通过二维单元格内粒子模拟，我们证明了透明质子的抑制和加速质子束能量散布的显着改善。这是通过修改后的靶设计实现的，其中将相对论密度不足的厚（微米尺寸）靶放置在经受辐射压力加速（RPA）的薄（纳米尺寸）加速箔的后面。由厚靶内部的电子提供的返回电流通过提高靶的密度并减小靶的横向调制，在透明性抑制中起着至关重要的作用。