Université Bordeaux-CEA-CNRS, Centre Lasers Intenses et Applications, UMR 5107, 351 Cours de la Libération, 33405 Talence, France.
GSI Helmholtzzentrum für Schwerionenforschung GmbH, Planckstrasse 1, 64291 Darmstadt, Germany.
Nat Commun. 2017 Jun 1;8:15693. doi: 10.1038/ncomms15693.
The energy deposition of ions in dense plasmas is a key process in inertial confinement fusion that determines the α-particle heating expected to trigger a burn wave in the hydrogen pellet and resulting in high thermonuclear gain. However, measurements of ion stopping in plasmas are scarce and mostly restricted to high ion velocities where theory agrees with the data. Here, we report experimental data at low projectile velocities near the Bragg peak, where the stopping force reaches its maximum. This parameter range features the largest theoretical uncertainties and conclusive data are missing until today. The precision of our measurements, combined with a reliable knowledge of the plasma parameters, allows to disprove several standard models for the stopping power for beam velocities typically encountered in inertial fusion. On the other hand, our data support theories that include a detailed treatment of strong ion-electron collisions.
离子在稠密等离子体中的能量沉积是惯性约束聚变中的一个关键过程，它决定了 α 粒子的加热，预计会在氢球体内引发燃烧波，并产生高的热核聚变增益。然而，对等离子体中离子阻止的测量很少，而且大多局限于高离子速度，在那里理论与数据相符。在这里，我们报告了在接近布拉格峰的低弹丸速度下的实验数据，在那里阻止力达到最大值。这个参数范围具有最大的理论不确定性，直到今天还缺少结论性的数据。我们测量的精度，结合对等离子体参数的可靠了解，使得可以否定几种标准的阻止力模型，这些模型通常用于惯性聚变中的束流速度。另一方面，我们的数据支持包括对强离子-电子碰撞的详细处理的理论。
