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Hu TX, Wu D, Sheng ZM, Zhang J. Exact dispersion relation of the quantum Langmuir wave. Phys Rev E 2024; 109:065213. [PMID: 39020969 DOI: 10.1103/physreve.109.065213] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2024] [Accepted: 06/10/2024] [Indexed: 07/20/2024]
Abstract
The normal modes, i.e., the eigensolutions to the dispersion relation equation, are the most fundamental properties of a plasma. The real part indicates the intrinsic oscillation frequency while the imaginary part the Landau damping rate. In most of the literature, the normal modes of quantum plasmas are obtained by means of small damping approximation, which is invalid for high-k modes. In this paper, we solve the exact dispersion relations via the analytical continuation scheme, and, due to the multi-value nature of the Fermi-Dirac distribution, reformation of the complex Riemann surface is required. It is found that the topological shape of the root locus in quantum plasmas is quite different from classical ones, in which both real and imaginary frequencies of high-k modes increase with k steeper than the typical linear behavior in classical plasmas. As a result, the time-evolving behavior of a high-k initial perturbation becomes ballistic-like in quantum plasmas.
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Liang T, Wu D, Ning X, Shan L, Yuan Z, Cai H, Sheng Z, He X. Large-scale kinetic simulations of colliding plasmas within a hohlraum of indirect-drive inertial confinement fusion. Phys Rev E 2024; 109:035207. [PMID: 38632725 DOI: 10.1103/physreve.109.035207] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Accepted: 02/13/2024] [Indexed: 04/19/2024]
Abstract
The National Ignition Facility has recently achieved successful burning plasma and ignition using the inertial confinement fusion (ICF) approach. However, there are still many fundamental physics phenomena that are not well understood, including the kinetic processes in the hohlraum. Shan et al. [Phys. Rev. Lett. 120, 195001 (2018)0031-900710.1103/PhysRevLett.120.195001] utilized the energy spectra of neutrons to investigate the kinetic colliding plasma in a hohlraum of indirect drive ICF. However, due to the typical large spatial-temporal scales, this experiment could not be well simulated by using available codes at that time. Utilizing our advanced high-order implicit PIC code, LAPINS, we were able to successfully reproduce the experiment on a large scale of both spatial and temporal dimensions, in which the original computational scale was increased by approximately seven to eight orders of magnitude. Not only is the validity of the explanation of the experiment confirmed by our simulations, i.e., the abnormally large width of neutron spectra comes from beam-target nuclear fusions, but also a different physical insight into the source of energetic deuterium ions is provided. The acceleration of deuterium ions can be categorized into two components: one is propelled by a sheath electric field created by the charge separation at the onset, while the other is a result of the reflection of the potential of the shock wave. The robustness of the acceleration mechanism is analyzed with varying initial conditions, e.g., temperatures, drifting velocity, and ion components. This paper might serve as a reference for benchmark simulations of upcoming simulation codes and may be relevant for future research on mixtures and entropy increments at plasma interfaces.
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Affiliation(s)
- Tianyi Liang
- Institute for Fusion Theory and Simulation, School of Physics, Zhejiang University, Hangzhou 310058, China
| | - Dong Wu
- Key Laboratory for Laser Plasmas and School of Physics and Astronomy, and Collaborative Innovation Center of IFSA, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Xiaochuan Ning
- Institute for Fusion Theory and Simulation, School of Physics, Zhejiang University, Hangzhou 310058, China
| | - Lianqiang Shan
- National Key Laboratory of Plasma Physics, Research Center of Laser Fusion, CAEP, Mianyang 621900, China
| | - Zongqiang Yuan
- National Key Laboratory of Plasma Physics, Research Center of Laser Fusion, CAEP, Mianyang 621900, China
| | - Hongbo Cai
- Institute of Applied Physics and Computational Mathematics, Beijing 100094, China
| | - Zhengmao Sheng
- Institute for Fusion Theory and Simulation, School of Physics, Zhejiang University, Hangzhou 310058, China
| | - Xiantu He
- Institute for Fusion Theory and Simulation, School of Physics, Zhejiang University, Hangzhou 310058, China
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Hu TX, Liang JH, Sheng ZM, Wu D. Kinetic investigations of nonlinear electrostatic excitations in quantum plasmas. Phys Rev E 2022; 105:065203. [PMID: 35854485 DOI: 10.1103/physreve.105.065203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Accepted: 05/18/2022] [Indexed: 06/15/2023]
Abstract
For plasmas in an extremely high-density state, like stellar cores or compressed fuel in inertial fusion facilities, their behavior turns out to be quite different when compared with those plasmas in interstellar space or magnetic confinement devices. To figure out those differences and uncover the kinetic physics in electrostatic excitations, a quantum kinetic code solving Wigner-Poisson equations has been developed. Basic plasmon decay, Landau damping, and two-stream instability of extremely high-density plasmas are investigated by using our newly developed code. Numerical simulations show that in the linear region, the dispersion relations of intrinsic modes can be significantly affected by quantum effects, and such simulation results can be well described by the existing analytical theory. Especially in the nonlinear region, since the space-time scale of collective modes of plasmas is comparable to the electron de Broglie wavelength, their couplings produce some new physics: the energy exchange between the electron and the collective mode results in an abnormal oscillation that does not exist in classical plasmas.
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Affiliation(s)
- Tian-Xing Hu
- Institute for Fusion Theory and Simulation, School of Physics, Zhejiang University, Hangzhou 310027, China
| | - Jiong-Hang Liang
- Institute for Fusion Theory and Simulation, School of Physics, Zhejiang University, Hangzhou 310027, China
| | - Zheng-Mao Sheng
- Institute for Fusion Theory and Simulation, School of Physics, Zhejiang University, Hangzhou 310027, China
| | - Dong Wu
- Key Laboratory for Laser Plasmas and School of Physics and Astronomy, Collaborative Innovation Center of IFSA, Shanghai Jiao Tong University, Shanghai 200240, China
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