Tahir N A, Neumayer P, Lomonosov I V, Shutov A, Bagnoud V, Piriz A R, Piriz S A, Deutsch C
GSI Helmholtzzentrum für Schwerionenforschung, 64291 Darmstadt, Germany.
Institute of Problems of Chemical Physics, Russian Academy of Sciences, 142432 Chernogolovka, Russia and Lomonosov Moscow State University, GSP-1, Leninskie Gory, 119991 Moscow, Russia and Moscow Institute of Physics and Technology, 141701 Dolgoprudny, Russia.
Phys Rev E. 2020 Feb;101(2-1):023202. doi: 10.1103/PhysRevE.101.023202.
The work presented in this paper shows with the help of two-dimensional hydrodynamic simulations that intense heavy-ion beams are a very efficient tool to induce high energy density (HED) states in solid matter. These simulations have been carried out using a computer code BIG2 that is based on a Godunov-type numerical algorithm. This code includes ion beam energy deposition using the cold stopping model, which is a valid approximation for the temperature range accessed in these simulations. Different phases of matter achieved due to the beam heating are treated using a semiempirical equation-of-state (EOS) model. To take care of the solid material properties, the Prandl-Reuss model is used. The high specific power deposited by the projectile particles in the target leads to phase transitions on a timescale of the order of tens of nanosecond, which means that the sample material achieves thermodynamic equilibrium during the heating process. In these calculations we use Pb as the sample material that is irradiated by an intense uranium beam. The beam parameters including particle energy, focal spot size, bunch length, and bunch intensity are considered to be the same as the design parameters of the ion beam to be generated by the SIS100 heavy-ion synchrotron at the Facility for Antiprotons and Ion Research (FAIR), at Darmstadt. The purpose of this work is to propose experiments to measure the EOS properties of HED matter including studies of the processes of phase transitions at the FAIR facility. Our simulations have shown that depending on the specific energy deposition, solid lead will undergo phase transitions leading to an expanded hot liquid state, two-phase liquid-gas state, or the critical parameter regime. In a similar manner, other materials can be studied in such experiments, which will be a very useful addition to the knowledge in this important field of research.
本文所展示的工作借助二维流体动力学模拟表明，强重离子束是在固体物质中诱导高能量密度（HED）状态的一种非常有效的工具。这些模拟是使用基于戈东诺夫型数值算法的计算机代码BIG2进行的。该代码包括使用冷阻止模型的离子束能量沉积，这对于这些模拟所涉及的温度范围是一种有效的近似。由于束流加热而实现的物质不同相态，使用半经验状态方程（EOS）模型进行处理。为了考虑固体材料特性，采用了普朗特 - 罗伊斯模型。入射粒子在靶中沉积的高比功率导致在几十纳秒量级的时间尺度上发生相变，这意味着样品材料在加热过程中达到热力学平衡。在这些计算中，我们使用铅作为被强铀束辐照的样品材料。束流参数，包括粒子能量、焦斑尺寸、束团长度和束团强度，被认为与达姆施塔特反质子与离子研究设施（FAIR）的SIS100重离子同步加速器所产生的离子束的设计参数相同。这项工作的目的是提出实验来测量HED物质的EOS特性，包括在FAIR设施中对相变过程的研究。我们的模拟表明，取决于特定的能量沉积，固态铅将经历相变，导致形成膨胀的热液态、气液两相态或临界参数区域。以类似的方式，其他材料也可以在这样的实验中进行研究，这将是对这一重要研究领域知识的非常有用的补充。
