Experimental research in plasma and high energy density physics at ELI infrastructure will be mainly oriented to fundamental science. This will accumulate scientific knowledge of new regimes of laser and secondary source interactions with targets and investigate unique states of matter that can be prepared only with ELI infrastructure.

Research Activity Description

ELI will offer interaction areas with excellent parameters and complementary characteristics allowing experimental setups that are not feasible in any other existing laser laboratory. Experiments will profit from 2 basic distinctions:

1. superior focused laser intensity, and
2. synergy of laser and secondary sources.

The basic goal of this research activity is to identify an indicative list of the important directions of plasma and high energy density physics research at ELI. This list is intended as a guideline for the design of flexible target area facilities devoted to plasma and HEDP studies, and for the choice of basic on-site diagnostic equipment. Active diagnostic methods will be developed, examined and prepared for fielding in selected experiments. Experimental set-ups for preliminary experiments testing the experimental areas and on-site diagnostics will be elaborated. Theoretical analysis and numerical simulations will be carried out as a basis for the design of the selected anticipated initial experiments at ELI.

We will briefly summarize here an indicative list of the important directions of plasma and high energy physics research at ELI:

1. Nonlinear optics of plasmas and laser interactions with underdense plasmas
2. Relativistic HED plasma
3. Laser interaction with solid targets and dense matter
4. Laser interactions with clusters and mass-limited targets
5. Warm dense matter studies
6. Stopping of a proton beam in a pre-generated plasma
7. Testing of advanced nuclear fusion schemes

The above brief list indicates that the possibility to exploit at least 2 energetic femtosecond laser beams together with at least one beam with longer pulse (non-compressed nanosecond pulse or pulse compressed to ps range) would be vital for many experiments. It may be advantage for many experiments to exploit the advanced secondary sources available at ELI, i.e. coherent or incoherent x-rays, electron and ion beams generated in an extra target chamber. Consequently, special ports have to be available for the secondary sources and special equipment for pointing and focusing of secondary sources into experimental target chamber.

The interaction chamber(s) have to be prepared for various types of targets, such as gas jets of various forms, cryogenic gas jets producing clusters, micro-droplets produced by pulse nozzles, capillary targets for laser guiding, thin foils etc. High-precision automatic target manipulation and pointing must be provided.

The interaction chamber(s) must be equipped with the basic optical, x-ray and particle diagnostics. Active optical and x-ray diagnostics using shadowgraphy, interferometry and Thomson scattering must be possible. The interaction area(s) must be shielded properly.

The basic output for applications will include:

1. New and substantially enhanced schemes for x-ray, electron and ion beam sources. These schemes will be also applied in the ELI secondary sources. The potential improvements in their parameters will enhance their application potential significantly.
2. Key data for astrophysics (equations of state, opacities, transport properties of warm dense matter) will be well measured. Astrophysical phenomena will be explained using scalable laboratory experiments at ELI.
3. Physical issues of advanced fusion schemes will be addressed at ELI. A lot of data important for ICF, such as proton and ion ranges and stopping powers in dense plasmas, will be measured at ELI.
4. Interaction experiments will be directly used in material science, for example for understanding the aging process in construction materials, which are subject to extreme operating conditions.
5. Intense and short positron pulses produced at ELI may be used in several techniques of material analysis, for instance for construction of positron microscope.
6. Results of research performed at ELI could be used by other experimental groups as a basis for study of technologies for nuclear transmutation of long-lived radioactive isotopes into less radioactive or short-lived products.
7. Plasma lenses for focusing of charged particle beams will be investigated at ELI. They can be applied both in ELI secondary sources and in conventional accelerators.

Main outcomes of the Research Activity

Within this Research Activity, it will be built a unique infrastructure for plasma and high energy density studies. As an international large-scale user facility, the interaction areas at ELI must provide versatile, user-friendly environment for a broad range of plasma and high energy density physics experiments. Taking the advantage of inherent synchronization of all ELI lasers which originate from one master oscillator, it must be possible to perform various interaction experiments with preformed plasmas and pump-probe experiments. The on-site diagnostics equipment must be properly chosen and well tested.
Experimental research in plasma and high energy density physics at ELI infrastructure will accumulate scientific knowledge of new regimes of laser and secondary source interactions with targets and investigate unique states of matter that can be prepared only with ELI infrastructure. However, there is also a large application potential of the plasma and interaction physics investigated at ELI.