Multi-University Center of Excellence for Pulsed-Power-Driven High-Energy Density Science: Mission

The mission of the Center is to carry out world class experimental, theoretical, and computational high energy density laboratory plasma (HEDLP) physics research, through fundamental studies and applications of magnetized high energy density (HED) plasmas produced by pulsed power machines, and to train the next generation of HEDLP research scientists. The Center of Excellence carries out experiments in a variety of configurations, all of which are current-driven, hot, dense plasmas that fit within the general name “dense Z-pinches.” The experiments are supported by computer simulations and theoretical modeling in order to help achieve an understanding of the experimental results and to help validate the computer simulations and theoretical models. Our work is fundamental HED physics and to applications of importance in Stewardship Sciences and in other fields. These applications include inertial confinement fusion, the development of intense plasma radiation sources, and understanding observed high energy astrophysical observations.

The Center has HED expertise and high quality facilities and will collaborate to address physics questions on magnetized HED plasmas of importance to the Stewardship Sciences Program. Specifically, we produce magnetized HED plasmas in a variety of configurations using gas puffs, thin foils or arrays of fine wires driven by 0.3 – 1.5 million ampere pulsed power generators that are in operation at Center partner institutions. The research is predominantly experimental, coupled with a substantial theory and simulation component to help achieve a better understanding of the physics of the experiments.

Participants

Principal Investigators

  • Professor David A. Hammer
  • Professor Bruce R. Kusse

Co-Principal Investigator

  • Professor Charles E. Seyler

Senior Research Associate

  • Dr. John Greenly

X-ray spectroscopic studies of X-pinch plasmas with 3-5 picosecond resolution: a quest for clear experimental evidence for radiative collapse

A cylindrical plasma carrying current along its axis is subject to a radially inward magnetic pressure that is proportional to the square of the current. If this inward pressure exceeds the outwardly directed plasma thermal pressure, the plasma to accelerates inward. This configuration is commonly known as a “Z-pinch,” referring to the Z-axis in a cylindrical coordinate system. Dense Z-pinch plasmas produced from current-carrying exploding wires frequently produce very brief (less than 0.1 nanosecond), intense, bursts of soft X-rays from tiny (about 1 micrometer), very hot (10-30 million K) regions of the plasma. This project addresses the physical processes that lead to those tiny high energy density plasmas.

Participants

Principal Investigator

  • Professor David A. Hammer

The Consequences of Rayleigh-Taylor Instabilities on Implosion Dynamics in Gas-puff Z-pinch Experiments

Gas-puff z-pinch experiments will be carried out in which the strength and character of the Rayleigh-Taylor Instabilities (RTI) will be varied by varying the gas species and initial gas density profile produced by a triple-nozzle gas-puff valve. The difference in the implosion.

Participants

Principal Investigator

  • Professor David A. Hammer

Relativistic Modeling Capabilities in PERSEUS Extended MHD Simulation Code
for HED Plasmas

Primary objective to self-consistently model relativistic high-energy-density (HED) laboratory and astrophysical phenomena. Electrons and ions in a plasma are generally modeled either as fluids using a two-fluid code or as particles using a Particle-In-Cell (PIC) code.

Participants

Principal Investigator

  • Professor Charles E. Seyler

Magnetized High-Energy-Density Plasma Flows Driven by Skin Effects
for HED Plasmas

This is a renewal proposal for our integrated program of experiments and simulations of HED plasma flows driven by skin effects. In our present program, “Experimental and Computational Studies of High Energy Density Plasma Streams Ablated from Fine Wires”, we have identified and begun to investigate a new regime of use of pulsed-power drivers in which the reversal of voltage after peak current is used to drive an “inverse skin effect” that produces high-velocity plasma outflows and shocks instead of imploding flows. Specifically, we have investigated a magnetic reconnection configuration that produces super-alfvenic and supersonic outflows bounded by radiative shocks at the separatrix. However, similar effects can also occur during the rise of current if the load inductance increases faster than a certain threshold, as is often true of imploding pinches. Furthermore, skin effects are ubiquitous in the initial breakdown and magnetization of pulsed-power driven loads such as cylindrical liners, wires and gas puffs, as well as the plasmas formed in power feeds and convolutes.

Participants

Principal Investigator

  • Dr. John B. Greenly

Co-Principal Investigator

  • Professor Charles E. Seyler