The frontiers of physical exploration have come down to understanding the infinitely small (quantum mechanics) and the infinitely large (astrophysics): the physics of extremes. Everything in between has now virtually been covered. The next step in ground-breaking discoveries faces a big challenge : studying matter that does not exist naturally on Earth because it is too dense to be stable at atmospheric pressures or much too large to fit in a laboratory. In the hope to solve this problem, scientists need to develop new instruments able to handle an even higher degree of energy density required to produce such matter. They also need new theories able to capture the behavior of matter is such exotic physical states. The terrain to cover is vast and the task is multi-generational. In the past years, two Grand Challenges of modern physics were formulated:
• What are the macroscopic properties (e.g. viscosity, conductivity)  of strongly interacting quantum systems?
• How do giant planets form and evolve?

HADES (the High Amperage Driver for Extreme States) offers a unique opportunity to to answer these questions by studying the properties of materials under millions of atmospheric pressure, conditions found no where on Earth or inside it). HADES will focus 250 GW of power inside a small material sample, the size of a pencil lead, a power equivalent to that of 250 commercial power plants. In a fraction of a second the material will be compressed to pressure only found in the core of Jupiter or at the surface of neutron stars.

This project is fully supported by the National Science Foundation (NSF). A description of the award can be found here. According to the NSF, HADES will "enable potentially transformative studies of extreme states of matter in a university environment, where students will have first-hand experience in both constructing and operating a world-class facility for high energy density science." HADES sprouted from a collaboration between the University of Rochester and several hghier education institutions namely, Cornell University, the University of Iowa, the University of Michigan, Stanford University, Idaho State University and Princeton University. A press release can be found here.

 HADES ipad

A perspective view of HADES showing the high energy density capacitors (white), capable of producing up to 250 GW of power and the load region (red and blue) visisble inside the vacuum vessel (gray). The whole machine can be controlled using an iPad, shown next to the vacuum vessel.

The table below give a summary of HADES capabilities:

Table summarizing HADES capabilities.

Design

The design of HADES follows a few critical principles:
• The geometry is open, side-on and end-on diagnostic access are necessary;
• The driver is movable. It can be transported and integrated into large x-ray source facilities.
Further, since all components are virtually identical, the current rise time repeatability is limited only by trigger jitter, which is less than 5 ns.

 

A brick made up with two capacitors is at the heart of HADES. HADES uses 130 bricks to generate 250 GW.

HADES' brick shown above forms the heart and soul of the machine. These bricks are arranged inside cavities know as linear transformer drivers or LTDs. This system was developed at by scientists at High Current Electronic Institute (HCEI), Tomsk, Russia and Sandia National Laboratories. LTDs have run successful research campaigns both at the University of Michigan and Imperial College in London, UK. More information regarding the design can be found here.

Research using HADES

Macroscopic quantum-degenerate matter: Understanding the formation and evolution of large rocky planets

Simulation of the compression of solid aluminum rod using HADES. The initial diameter of the rod is 1.2 mm in diameter (inductance 8 nH). At peak compression, 200 ns after current start, the rod is in a homogenous warm dense matter regime with a number density of 3.4x1030 m-3 and a temperature of 1 eV. Figure dimensions are in mm.

This project will enable the research team to study matter under extreme pressures under a variety of configurations. For instance, HADES will allow scientists to assemble matter only found at the center of gas giants or mega-Earths. HADES uses an electrical current to heat the sample and the resulting magnetic field compresses the sample, keeping the high pressure matter confined. The combination of heating and confinement eliminates the short time constraint required by conventional techniques. The power requirements are therefore reduced, reducing material strains of the driver while allowing an increase of the overall driver energy. When larger samples are produced, the signal-to-noise ratio greatly improves, reducing the stringent requirements imposed on x-ray sources. Isochoric heating requires the sample to be surrounded by a pre-ionized gas puff . We used the two-fluid MHD code PERSEUS to compute the properties at maximum compression and summarized in the figure above. The ultra-dense sample is relatively homogeneous. Using this technique, HADES can generate strongly coupled matter where quantum degeneracy dominates.

Supersonic flows under intense magnetic fields: Understanding the dynamics of astrophysical flows

Twisted pin experiment used to produce axial magnetic fields onto plasma jets using 1.2 MA current from HADES to produce magnetized plasma jet found near black holes.

Using HADES we will study the impact of magnetic fields on plasma outflows. In particular, we would like to discover the role of magnetic fields in particle and energy transport, the mechanisms responsible for flow collimation and stability, the resilience of magnetized and non-magnetized plasma jet to internal and external perturbations. We know that the jet shape can be influenced by the strength of the field. This issue was investigated in radial foil configurations where plasma is readily available at the base of the jet. In this case, the strength of the axial magnetic field cannot prevent the plasma from reaching the base of the jet since ablation happens everywhere on the foil. In the case of an high energy density plasma plasma accretion disk, the situation is different since the plasma has to travel across the disk before being injected in the jet. If the axial field is too strong, the plasma flows slowly across field lines and the influx of matter at the base of the jet is reduced, impacting the mass density of the outflow. We propose to study the extent to which axial magnetic fields can shape the outflow while keeping the mass flow rate unchanged. Further, the alignment of the field with the jet axis seems critical to the jet orientation . We will define to which extent the magnetic fields can bend outflows when they are not aligned with the jet axis. Numerical simulations will be used to show how gravitational pull and magnetic field shapes the jet together.

HADES will be built on campus, in the Extreme State Physics Laboratory (XSPL). HADES will be operated, at the XSPL, LLE and light sources at National Laboratories (e.g. LCLS and DCS).