Self-generated surface magnetic fields inhibit laser-driven sheath acceleration of high-energy protons.
Self-generated surface magnetic fields inhibit laser-driven sheath acceleration of high-energy protons.
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自生成的表面磁场抑制了高能质子的激光驱动的鞘加速度。
DOI：
10.1038/s41467-017-02436-w
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发表时间：
2018-01-18
影响因子：
16.6
通讯作者：
Fuchs J
中科院分区：
文献类型：
--
作者：
Nakatsutsumi M;Sentoku Y;Korzhimanov A;Chen SN;Buffechoux S;Kon A;Atherton B;Audebert P;Geissel M;Hurd L;Kimmel M;Rambo P;Schollmeier M;Schwarz J;Starodubtsev M;Gremillet L;Kodama R;Fuchs J
高强度激光与固体箔相互作用产生大量的相对论电子，这反过来又在靶周围产生强大的鞘电场。在这样的领域加速的质子束具有显着的属性，使超快等离子体现象或等容加热的致密材料的射线照相。鉴于长期的多学科目的（例如，尽管质子能量可以用于放射性中子源或癌症治疗），但目前的挑战是实现远超过100 MeV的质子能量，这通常被认为是可能的，通过提高靶上激光强度。在这里，我们提出的实验和数值计算结果表明，静磁场在目标表面上自生可能会造成一个基本的限制鞘层驱动的离子加速足够高的激光强度。这些场可以足够强（在激光强度~1021 W cm-2时~105 T），以磁化鞘电子并使质子偏离加速区域，从而降低后者可以获得的最大能量。近年来，随着超强激光的发展，激光离子加速受到越来越多的关注。在这里，作者证明了自生磁场对离子加速的作用和激光强度对能量标度的限制。
High-intensity lasers interacting with solid foils produce copious numbers of relativistic electrons, which in turn create strong sheath electric fields around the target. The proton beams accelerated in such fields have remarkable properties, enabling ultrafast radiography of plasma phenomena or isochoric heating of dense materials. In view of longer-term multidisciplinary purposes (e.g., spallation neutron sources or cancer therapy), the current challenge is to achieve proton energies well in excess of 100 MeV, which is commonly thought to be possible by raising the on-target laser intensity. Here we present experimental and numerical results demonstrating that magnetostatic fields self-generated on the target surface may pose a fundamental limit to sheath-driven ion acceleration for high enough laser intensities. Those fields can be strong enough (~105 T at laser intensities ~1021 W cm–2) to magnetize the sheath electrons and deflect protons off the accelerating region, hence degrading the maximum energy the latter can acquire. Laser-generated ion acceleration has received increasing attention due to recent progress in super-intense lasers. Here the authors demonstrate the role of the self-generated magnetic field on the ion acceleration and limitations on the energy scaling with laser intensity.
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影响因子：
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通讯作者：
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