High-energy density physics (HEDP) at HIAF

High energy density matter, usually referred to the extreme state of matter interior energy density above 10¹¹J/m³ or equivalently pressure exceeding 1 Mbar. Such extreme states of matter are prevalent in the interior stars, giant planets and core of the earth, as well the implosion capsule in inertial confinement fusion process. It is very challenging to explain new phenomena with existing theoretical models, because of the strong coupling effect and the partially degenerate electron component. The equation-of-state, physical property of matter around critical point, phase transition, insulator-metal transition, hydrodynamic instability and transport properties are very interesting for scientists.      

High energy density matter driven by intense heavy ions at HIAF offers a new worldwide unique possibility to conduct the experimental research on extreme astrophysical conditions and the implosion process in ICF in laboratory. More than 160 kJ/g energy will be deposited into a a large volume solid target by using 10¹² ppp U⁹²⁺ with 2 GeV/u energy, 100 ns pulse length and 1 mm beam spot, which result in a volumetric heating up to ~10 eV and the density remains solid state. 2 in 1 shooting mode will be available in HIAF-upgrade phase, where two beams from the SRing and the BRing to firstly compress the target to a higher density and secondly directly heat it to a higher temperature, respectively. As a result, a more exotic state of matter will be produced. Many advanced diagnostic capabilities with high spatial and temporal resolution are proposed to experimentally investigate the dynamic events in HEDP at HIAF

Schematic illustration of HIAF and its upgrading. The HEDP terminal will update from the initial SRing region (HED-TI) to the middle position between BRing and SRing (HED-TII). Multi-beam-shooting modes are accessible at HED terminal: 1. one beam from SRing-1 to pre-compress target and the other from BRing-1 to heat the compressed target; 2. Sequenced hollow beams from SRing and BRing respectively to cascade compress the target to a ultra dense state; and so on.

[1] R. Cheng, et.al., Matter and Radiation at Extremes 3 (2018) 85-93

[2] R.Cheng, et.al., Science in China Series G-Physics, Mechanics & Astronomy (in Chinese), 50, 112011 (2020);

[3] Y.Zhao, et.al., Science in China Series G-Physics, Mechanics & Astronomy (in Chinese), 50, 112004 (2020);

Instruments/Diagnostics for HEDM    

HEDM will be generated by means of intense heavy ion beams at HED terminal at HIAF, where a large amount of energy will be deposited into target within 150 ns. Several kinds of instruments, including but not limited to streak camera, X-ray framing camera, VISAR, displacement interferometer, X-ray and XUV spectroscopy, high-energy-electron-radiography will be installed to diagnose the exotic state of matter and provide the importance experimental data to answer the questions on equitation of state. 

Meantime, all instruments are synchronized with beam shot and deliver the acquired data every shot, thus a control and data acquisition system is developed to store the data and eventually preprocessed in due time.

Kinds of high temporal and spatial resolution diagnostics will be installed around the target, including the streaked-optical-pyrometer，VISAR，displacement interferometer, X-ray framing camera, X-ray and XUV spectroscopy, high-energy-electron-radiography and so on.

[1]R.Cheng, et al., Laser and Particle beams 30 (2012) 679-706

[2] J.Xiao, et.al., Chin. Phys. B Vol. 27, No. 3 (2018) 035202

Strong-coupled ultracold neutral plasmas     

In recent years, ultracold neutral plasmas (UNPs), as strongly coupled plasma available in the laboratory, have gradually been the focus in the experimental and theoretical plasma physics studies ^[1]. We have built magneto-optical traps for the Rb atom and Ca atom, and produced the UNPs through photoionization of cold atoms. Some characteristic parameter, such as the potential well depth, the threshold ion number, the lifetime of UNP have been experimentally investigated ^[2]. Here, we propose to study the temperature of UNPs, as well as the Coulomb coupling parameter, through the state-of-the-art ion velocity map imaging (VMI) technique, which can measure the kinetic energy distribution of charged particles accurately ^[3]. In addition, we propose to study the cold collision dynamics between cold atoms and ions by a hybrid trap, which combines a MOT with a linear Paul trap overlapping in space.

Magneto-optical trap and Zeeman slower with consecutive coils for cooling and trapping atoms.

[1] T. C. Killian, Nature 429, 24 (2004); Nature 441, 18 (2006); Science 316, 4 (2007); Science 363, 61 (2019)

[2] Syed Zaheeruddin, Yufan Li, Dongmei Zhao, Xinwen Ma and Jie Yang  Plasma Sci. Technol. 20, 085001 (2018)

[3] Yu-Fan Li, Dong-Mei Zhao, Wen-Chang Zhou, Dong-Bin Qian, Jie Yang, Shao-Feng Zhang, Xiao-Long Zhu, Xin-Wen Ma, International Journal of Mass Spectrometry 442 (2019) 23-28

Microscopic mechanism of interaction between ion beam with dense matter or plasma

Interaction of ion beam with matter has always been a classical topic of atomic physics and plasma physics. The energy deposition in the low-energy range as well as interaction with degenerate matter is of importance for very intense heavy ion beams which eventually deliver a high-power-density deposition of energy to drive an inertial fusion target. The energy loss and charge exchange reactions of ion beams with hot, ionized matter play an important role in the researches of heavy-ion beam-driven high-energy-density physics in matter and inertial confinement fusion.

Based on the HIRFL, an experimental platform for ion beam-plasma interaction is completed to investigate the energy loss, charge state and wake field of plasma on beams.  Not only kinds of ions with different energy and initial charge state, but also several plasma devices: gas-discharged plasma, RF plasma, theta-pinch plasma and laser-plasma can be applied respectively, thus the systematical experiments can be performed. Meantime, the ab initial, numerical simulation and other theoretical calculations are developed in order to understand the interaction mechanism details.

Low energy regime ion beam-plasma interaction experimental setup at IMP. Kinds of ions accelerated from an ECR ion source transmit to the plasma target area, the energy loss and charge state distribution, as well as wake field effect are experimentally investigated.

[1] Cheng R et al, Laser and Particle Beams 36, 98–104 (2018).

[2] J.Ren, et.al., NATURE COMMUNICATIONS | (2020) 11:5157 |

[3]Y.N. Zhang, et.al., Phys. Plasmas 27, 093107 (2020);