The Ultra high Intensity Roadmap is represented in Fig 2. It depicts the laser intensity as a function of years. The different regimes of interest are shown in different colors. The green is the relativistic regime where I > 1018W/cm2 with one MeV quiver energy. The laser field is large enough to accelerate the electron close to the speed of light. In the yellow region it is the proton that can be accelerated to the speed of light at energy of about 1GeV. In the same regime the vacuum nonlinearities starts to be observable up to the orange regime, where the laser field is strong enough to breakdown the vacuum. At present it is anticipated that only the lasers built as part of the Extreme Light Infrastructure will be able to deliver intensities at the threshold of the yellow region.
Figure 2 : Laser Intensity through the years. Note the steep slope in intensities that occurred during the 1960s. This period corresponded to the discovery of most nonlinear optical effects due to the bound electron. We are today experiencing a similar rapid increase in intensity opening up a new regime in optics dominated by the relativistic character of the electron. Note that a few years ago we called it high intensity when the electron in a quiver energy was around 1eV. Today high intensity corresponds to electron’s quiver energy of the order of mc² about 0.5 MeV where m is the mass of the electron at rest and c is the speed of light. The solid red line corresponds to what could be obtained with a significant increase in beam size or by increasing the number of beams. On the other hand the red-dashed line corresponds to the “short cut” obtained using the double-compression technique.
It is therefore IZEST’s main mission to develop the next generation of lasers required for the next level of fundamental physics research. IZEST draws on the existing competencies of partner research labs and institutions from around the world to further develop strategies in laser-plasma interactions. Ultimately the goal of IZEST is to implement fundamental research experiments based on the pulse compression of already-built, large-scale lasers like the Laser Megajoule (LMJ) or the National Ignition Facility (NIF). IZEST endeavors also to explore new ways where a modest amount of energy is compressed over an exceedingly short duration i.e in, the subattosecond range to reach the exawatt level.
In the preparatory phases much of the theoretical and experimental studies can be completed by scientists in collaborating countries, including France, USA, Russia, Germany, Italy, Sweden, Japan, China, and Taiwan. In addition much of the foundational experimental experience can be gained by testing the theories developed and performing proof-of-principle studies at smaller-scale partner laser facilities, see examples in Fig.1a.
Since its inception in late 2011, the IZEST consortium have implemented five primary programs namely:
- laser technology and amplification such as the C3 (C-cubed) ;
- zeptosecond compression and Laser acceleration in novel media ;
- particle acceleration which includes the 100-GeV Ascent project as well as the acceleration in solid density plasma ;
- High-Energy fundamental physics which includes the “Dark Fields” and Non linear QED group.
- Coherent Amplification Network(CAN) providing the possibility to produce simultaneously ; peak power, average power and efficiency. This type of laser is using a revolutionary laser based on the phasing of a large bundle of fiber amplifiers.
It is within these five divisions that the work and collaborations upon specific tasks pertaining to the overall themes of IZEST are envisioned and executed. Members of IZEST become associated within each area as their expertise and interests warrant. The C3 and 100-GeV projects will be quite familiar to laser and plasma scientists because, in many ways, they pertain to the expansion and improvement of laser and particle acceleration technologies. The CAN project providing average power and efficiency is of paramount importance for the applications. However, the Dark Fields project recognizes that laser intensities are reaching a point that allows for applications to High-Energy Physics, a realm typically employing traditional accelerators. As laser technology becomes complementary to this energy regime it becomes a new playground for theorists to explore and propose new tests for our understanding of fundamental physics.The following sections are brief summaries of each division within the IZEST consortium.